Merge remote-tracking branch 'refs/remotes/facebook/dev' into dev11

2017-01-27 10:26:33 +01:00 · 2017-01-27 10:26:33 +01:00 · f63042e278
commit f63042e278
parent 5022a18d51 717c65d690
32 changed files with 2010 additions and 273 deletions
--- a/.gitignore
+++ b/.gitignore
@ -15,6 +15,7 @@

 # Executables
 zstd
+zstdmt
 *.exe
 *.out
 *.app
--- a/.travis.yml
+++ b/.travis.yml
@ -87,7 +87,17 @@ matrix:
            - gcc-aarch64-linux-gnu
            - libc6-dev-arm64-cross

-    - env: Ubu=14.04 Cmd='make ppctest && make clean && make ppc64test'
+    - env: Ubu=14.04 Cmd='make ppctest'
+      dist: trusty
+      sudo: required
+      addons:
+        apt:
+          packages:
+            - qemu-system-ppc
+            - qemu-user-static
+            - gcc-powerpc-linux-gnu
+
+    - env: Ubu=14.04 Cmd='make ppc64test'
      dist: trusty
      sudo: required
      addons:
@ -96,7 +106,6 @@ matrix:
            - qemu-system-ppc
            - qemu-user-static
            - gcc-powerpc-linux-gnu
-            - libc6-dev-armel-cross

    - env: Ubu=14.04 Cmd='make -C lib all && CFLAGS="-O1 -g" make -C zlibWrapper valgrindTest && make -C tests valgrindTest'
      os: linux
@ -126,7 +135,7 @@ matrix:

    - env: Ubu=14.04 Cmd="make gpptest && make clean && make gnu90test && make clean
                       && make c99test && make clean && make gnu99test && make clean
-                       && make clangtest && make clean && make -C contrib/pzstd googletest32 
+                       && make clangtest && make clean && make -C contrib/pzstd googletest32
                       && make -C contrib/pzstd all32 && make -C contrib/pzstd check && make -C contrib/pzstd clean"
      os: linux
      dist: trusty
--- a/7
+++ b/7
@ -50,6 +50,11 @@ zstd:
 	@$(MAKE) -C $(PRGDIR) $@
 	cp $(PRGDIR)/zstd$(EXT) .

+.PHONY: zstdmt
+zstdmt:
+	@$(MAKE) -C $(PRGDIR) $@
+	cp $(PRGDIR)/zstd$(EXT) ./zstdmt$(EXT)
+
 .PHONY: zlibwrapper
 zlibwrapper:
 	$(MAKE) -C $(ZWRAPDIR) test
@ -65,7 +70,7 @@ clean:
 	@$(MAKE) -C $(TESTDIR) $@ > $(VOID)
 	@$(MAKE) -C $(ZWRAPDIR) $@ > $(VOID)
 	@$(MAKE) -C examples/ $@ > $(VOID)
-	@$(RM) zstd$(EXT) tmp*
+	@$(RM) zstd$(EXT) zstdmt$(EXT) tmp*
 	@echo Cleaning completed


--- a/build/VS2008/zstd/zstd.vcproj
+++ b/build/VS2008/zstd/zstd.vcproj
@ -380,6 +380,14 @@
 				RelativePath="..\..\..\lib\decompress\huf_decompress.c"
 				>
 			</File>
+			<File
+				RelativePath="..\..\..\lib\common\pool.c"
+				>
+			</File>
+			<File
+				RelativePath="..\..\..\lib\common\threading.c"
+				>
+			</File>
 			<File
 				RelativePath="..\..\..\lib\common\xxhash.c"
 				>
@ -432,6 +440,10 @@
 				RelativePath="..\..\..\programs\zstdcli.c"
 				>
 			</File>
+			<File
+				RelativePath="..\..\..\lib\compress\zstdmt_compress.c"
+				>
+			</File>
 		</Filter>
 		<Filter
 			Name="Header Files"
@ -450,10 +462,6 @@
 				RelativePath="..\..\..\lib\common\error_private.h"
 				>
 			</File>
-			<File
-				RelativePath="..\..\..\lib\common\zstd_errors.h"
-				>
-			</File>
 			<File
 				RelativePath="..\..\..\lib\common\fse.h"
 				>
@ -474,6 +482,14 @@
 				RelativePath="..\..\..\lib\common\mem.h"
 				>
 			</File>
+			<File
+				RelativePath="..\..\..\lib\common\pool.h"
+				>
+			</File>
+			<File
+				RelativePath="..\..\..\lib\common\threading.h"
+				>
+			</File>
 			<File
 				RelativePath="..\..\..\lib\common\xxhash.h"
 				>
@ -490,6 +506,10 @@
 				RelativePath="..\..\..\lib\zstd.h"
 				>
 			</File>
+			<File
+				RelativePath="..\..\..\lib\common\zstd_errors.h"
+				>
+			</File>
 			<File
 				RelativePath="..\..\..\lib\common\zstd_internal.h"
 				>
@ -534,6 +554,10 @@
 				RelativePath="..\..\..\lib\legacy\zstd_v07.h"
 				>
 			</File>
+			<File
+				RelativePath="..\..\..\lib\compress\zstdmt_compress.h"
+				>
+			</File>
 		</Filter>
 	</Files>
 	<Globals>
--- a/build/VS2010/zstd/zstd.vcxproj
+++ b/build/VS2010/zstd/zstd.vcxproj
@ -21,11 +21,14 @@
  <ItemGroup>
    <ClCompile Include="..\..\..\lib\common\entropy_common.c" />
    <ClCompile Include="..\..\..\lib\common\error_private.c" />
+    <ClCompile Include="..\..\..\lib\common\pool.c" />
+    <ClCompile Include="..\..\..\lib\common\threading.c" />
    <ClCompile Include="..\..\..\lib\common\xxhash.c" />
    <ClCompile Include="..\..\..\lib\common\zstd_common.c" />
    <ClCompile Include="..\..\..\lib\common\fse_decompress.c" />
    <ClCompile Include="..\..\..\lib\compress\fse_compress.c" />
    <ClCompile Include="..\..\..\lib\compress\huf_compress.c" />
+    <ClCompile Include="..\..\..\lib\compress\zstdmt_compress.c" />
    <ClCompile Include="..\..\..\lib\compress\zstd_compress.c" />
    <ClCompile Include="..\..\..\lib\decompress\huf_decompress.c" />
    <ClCompile Include="..\..\..\lib\decompress\zstd_decompress.c" />
@ -46,7 +49,10 @@
    <ClCompile Include="..\..\..\programs\zstdcli.c" />
  </ItemGroup>
  <ItemGroup>
+    <ClInclude Include="..\..\..\lib\common\pool.h" />
+    <ClInclude Include="..\..\..\lib\common\threading.h" />
    <ClInclude Include="..\..\..\lib\common\xxhash.h" />
+    <ClInclude Include="..\..\..\lib\compress\zstdmt_compress.h" />
    <ClInclude Include="..\..\..\lib\dictBuilder\zdict.h" />
    <ClInclude Include="..\..\..\lib\dictBuilder\divsufsort.h" />
    <ClInclude Include="..\..\..\lib\common\fse.h" />
@ -67,6 +73,7 @@
    <ClInclude Include="..\..\..\programs\datagen.h" />
    <ClInclude Include="..\..\..\programs\dibio.h" />
    <ClInclude Include="..\..\..\programs\fileio.h" />
+    <ClInclude Include="..\..\..\programs\platform.h" />
    <ClInclude Include="..\..\..\programs\util.h" />
  </ItemGroup>
  <ItemGroup>
@ -138,7 +145,7 @@
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
    <LinkIncremental>false</LinkIncremental>
-    <IncludePath>$(IncludePath);$(SolutionDir)..\..\lib;$(SolutionDir)..\..\lib\legacy;$(SolutionDir)..\..\lib\common;$(SolutionDir)..\..\lib\dictBuilder;$(UniversalCRT_IncludePath);</IncludePath>
+    <IncludePath>$(IncludePath);$(SolutionDir)..\..\lib;$(SolutionDir)..\..\lib\compress;$(SolutionDir)..\..\lib\legacy;$(SolutionDir)..\..\lib\common;$(SolutionDir)..\..\lib\dictBuilder;$(UniversalCRT_IncludePath);</IncludePath>
    <RunCodeAnalysis>false</RunCodeAnalysis>
    <LibraryPath>$(LibraryPath);</LibraryPath>
  </PropertyGroup>
@ -207,6 +214,7 @@
      <TreatWarningAsError>false</TreatWarningAsError>
      <EnablePREfast>false</EnablePREfast>
      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <AdditionalOptions>/DZSTD_MULTITHREAD %(AdditionalOptions)</AdditionalOptions>
    </ClCompile>
    <Link>
      <SubSystem>Console</SubSystem>
@ -219,4 +227,4 @@
  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
  <ImportGroup Label="ExtensionTargets">
  </ImportGroup>
-</Project>
+</Project>
--- a/build/cmake/lib/CMakeLists.txt
+++ b/build/cmake/lib/CMakeLists.txt
@ -1,30 +1,10 @@
 # ################################################################
-# zstd - Makefile
-# Copyright (C) Yann Collet 2014-2016
-# All rights reserved.
-#
-# BSD license
-#
-# Redistribution and use in source and binary forms, with or without modification,
-# are permitted provided that the following conditions are met:
-#
-# * Redistributions of source code must retain the above copyright notice, this
-#   list of conditions and the following disclaimer.
-#
-# * Redistributions in binary form must reproduce the above copyright notice, this
-#   list of conditions and the following disclaimer in the documentation and/or
-#   other materials provided with the distribution.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
-# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
-# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# * Copyright (c) 2014-present, Yann Collet, Facebook, Inc.
+# * All rights reserved.
+# *
+# * This source code is licensed under the BSD-style license found in the
+# * LICENSE file in the root directory of this source tree. An additional grant
+# * of patent rights can be found in the PATENTS file in the same directory.
 #
 # You can contact the author at :
 #  - zstd homepage : http://www.zstd.net/
@ -58,13 +38,16 @@ MESSAGE("ZSTD VERSION ${LIBVER_MAJOR}.${LIBVER_MINOR}.${LIBVER_RELEASE}")

 SET(Sources
        ${LIBRARY_DIR}/common/entropy_common.c
+        ${LIBRARY_DIR}/common/fse_decompress.c
+        ${LIBRARY_DIR}/common/threading.c
+        ${LIBRARY_DIR}/common/pool.c
        ${LIBRARY_DIR}/common/zstd_common.c
        ${LIBRARY_DIR}/common/error_private.c
        ${LIBRARY_DIR}/common/xxhash.c
-        ${LIBRARY_DIR}/common/fse_decompress.c
        ${LIBRARY_DIR}/compress/fse_compress.c
        ${LIBRARY_DIR}/compress/huf_compress.c
        ${LIBRARY_DIR}/compress/zstd_compress.c
+        ${LIBRARY_DIR}/compress/zstdmt_compress.c
        ${LIBRARY_DIR}/decompress/huf_decompress.c
        ${LIBRARY_DIR}/decompress/zstd_decompress.c
        ${LIBRARY_DIR}/dictBuilder/cover.c
--- a/build/cmake/programs/CMakeLists.txt
+++ b/build/cmake/programs/CMakeLists.txt
@ -1,30 +1,10 @@
 # ################################################################
-# zstd - Makefile
-# Copyright (C) Yann Collet 2014-2016
-# All rights reserved.
-#
-# BSD license
-#
-# Redistribution and use in source and binary forms, with or without modification,
-# are permitted provided that the following conditions are met:
-#
-# * Redistributions of source code must retain the above copyright notice, this
-#   list of conditions and the following disclaimer.
-#
-# * Redistributions in binary form must reproduce the above copyright notice, this
-#   list of conditions and the following disclaimer in the documentation and/or
-#   other materials provided with the distribution.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
-# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
-# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
-# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# * Copyright (c) 2015-present, Yann Collet, Facebook, Inc.
+# * All rights reserved.
+# *
+# * This source code is licensed under the BSD-style license found in the
+# * LICENSE file in the root directory of this source tree. An additional grant
+# * of patent rights can be found in the PATENTS file in the same directory.
 #
 # You can contact the author at :
 #  - zstd homepage : http://www.zstd.net/
@ -40,7 +20,7 @@ SET(ROOT_DIR ../../..)
 # Define programs directory, where sources and header files are located
 SET(LIBRARY_DIR ${ROOT_DIR}/lib)
 SET(PROGRAMS_DIR ${ROOT_DIR}/programs)
-INCLUDE_DIRECTORIES(${PROGRAMS_DIR} ${LIBRARY_DIR} ${LIBRARY_DIR}/common ${LIBRARY_DIR}/dictBuilder)
+INCLUDE_DIRECTORIES(${PROGRAMS_DIR} ${LIBRARY_DIR} ${LIBRARY_DIR}/common ${LIBRARY_DIR}/compression ${LIBRARY_DIR}/dictBuilder)

 IF (ZSTD_LEGACY_SUPPORT)
    SET(PROGRAMS_LEGACY_DIR ${PROGRAMS_DIR}/legacy)
--- a/lib/Makefile
+++ b/lib/Makefile
@ -38,6 +38,8 @@ CPPFLAGS  += -I./legacy -DZSTD_LEGACY_SUPPORT=1
 ZSTD_FILES+= $(wildcard legacy/*.c)
 endif

+ZSTD_OBJ   := $(patsubst %.c,%.o,$(ZSTD_FILES))
+
 # OS X linker doesn't support -soname, and use different extension
 # see : https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/DynamicLibraries/100-Articles/DynamicLibraryDesignGuidelines.html
 ifeq ($(shell uname), Darwin)
@ -62,10 +64,9 @@ default: lib
 all: lib

 libzstd.a: ARFLAGS = rcs
-libzstd.a: $(ZSTD_FILES)
+libzstd.a: $(ZSTD_OBJ)
 	@echo compiling static library
-	@$(CC) $(FLAGS) -c $^
-	@$(AR) $(ARFLAGS) $@ *.o
+	@$(AR) $(ARFLAGS) $@ $^

 $(LIBZSTD): LDFLAGS += -shared -fPIC -fvisibility=hidden
 $(LIBZSTD): $(ZSTD_FILES)
@ -86,7 +87,7 @@ lib: libzstd.a libzstd

 clean:
 	@$(RM) core *.o *.a *.gcda *.$(SHARED_EXT) *.$(SHARED_EXT).* libzstd.pc dll/libzstd.dll dll/libzstd.lib
-	@$(RM) decompress/*.o
+	@$(RM) common/*.o compress/*.o decompress/*.o dictBuilder/*.o legacy/*.o deprecated/*.o
 	@echo Cleaning library completed

 #-----------------------------------------------------------------------------
--- a/lib/common/pool.c
+++ b/lib/common/pool.c
@ -0,0 +1,194 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+
+/* ======   Dependencies   ======= */
+#include <stddef.h>  /* size_t */
+#include <stdlib.h>  /* malloc, calloc, free */
+#include "pool.h"
+
+/* ======   Compiler specifics   ====== */
+#if defined(_MSC_VER)
+#  pragma warning(disable : 4204)        /* disable: C4204: non-constant aggregate initializer */
+#endif
+
+
+#ifdef ZSTD_MULTITHREAD
+
+#include <threading.h>   /* pthread adaptation */
+
+/* A job is a function and an opaque argument */
+typedef struct POOL_job_s {
+  POOL_function function;
+  void *opaque;
+} POOL_job;
+
+struct POOL_ctx_s {
+    /* Keep track of the threads */
+    pthread_t *threads;
+    size_t numThreads;
+
+    /* The queue is a circular buffer */
+    POOL_job *queue;
+    size_t queueHead;
+    size_t queueTail;
+    size_t queueSize;
+    /* The mutex protects the queue */
+    pthread_mutex_t queueMutex;
+    /* Condition variable for pushers to wait on when the queue is full */
+    pthread_cond_t queuePushCond;
+    /* Condition variables for poppers to wait on when the queue is empty */
+    pthread_cond_t queuePopCond;
+    /* Indicates if the queue is shutting down */
+    int shutdown;
+};
+
+/* POOL_thread() :
+   Work thread for the thread pool.
+   Waits for jobs and executes them.
+   @returns : NULL on failure else non-null.
+*/
+static void* POOL_thread(void* opaque) {
+    POOL_ctx* const ctx = (POOL_ctx*)opaque;
+    if (!ctx) { return NULL; }
+    for (;;) {
+        /* Lock the mutex and wait for a non-empty queue or until shutdown */
+        pthread_mutex_lock(&ctx->queueMutex);
+        while (ctx->queueHead == ctx->queueTail && !ctx->shutdown) {
+            pthread_cond_wait(&ctx->queuePopCond, &ctx->queueMutex);
+        }
+        /* empty => shutting down: so stop */
+        if (ctx->queueHead == ctx->queueTail) {
+            pthread_mutex_unlock(&ctx->queueMutex);
+            return opaque;
+        }
+        /* Pop a job off the queue */
+        {   POOL_job const job = ctx->queue[ctx->queueHead];
+            ctx->queueHead = (ctx->queueHead + 1) % ctx->queueSize;
+            /* Unlock the mutex, signal a pusher, and run the job */
+            pthread_mutex_unlock(&ctx->queueMutex);
+            pthread_cond_signal(&ctx->queuePushCond);
+            job.function(job.opaque);
+        }
+    }
+    /* Unreachable */
+}
+
+POOL_ctx *POOL_create(size_t numThreads, size_t queueSize) {
+    POOL_ctx *ctx;
+    /* Check the parameters */
+    if (!numThreads || !queueSize) { return NULL; }
+    /* Allocate the context and zero initialize */
+    ctx = (POOL_ctx *)calloc(1, sizeof(POOL_ctx));
+    if (!ctx) { return NULL; }
+    /* Initialize the job queue.
+     * It needs one extra space since one space is wasted to differentiate empty
+     * and full queues.
+     */
+    ctx->queueSize = queueSize + 1;
+    ctx->queue = (POOL_job *)malloc(ctx->queueSize * sizeof(POOL_job));
+    ctx->queueHead = 0;
+    ctx->queueTail = 0;
+    pthread_mutex_init(&ctx->queueMutex, NULL);
+    pthread_cond_init(&ctx->queuePushCond, NULL);
+    pthread_cond_init(&ctx->queuePopCond, NULL);
+    ctx->shutdown = 0;
+    /* Allocate space for the thread handles */
+    ctx->threads = (pthread_t *)malloc(numThreads * sizeof(pthread_t));
+    ctx->numThreads = 0;
+    /* Check for errors */
+    if (!ctx->threads || !ctx->queue) { POOL_free(ctx); return NULL; }
+    /* Initialize the threads */
+    {   size_t i;
+        for (i = 0; i < numThreads; ++i) {
+            if (pthread_create(&ctx->threads[i], NULL, &POOL_thread, ctx)) {
+                ctx->numThreads = i;
+                POOL_free(ctx);
+                return NULL;
+        }   }
+        ctx->numThreads = numThreads;
+    }
+    return ctx;
+}
+
+/*! POOL_join() :
+    Shutdown the queue, wake any sleeping threads, and join all of the threads.
+*/
+static void POOL_join(POOL_ctx *ctx) {
+    /* Shut down the queue */
+    pthread_mutex_lock(&ctx->queueMutex);
+    ctx->shutdown = 1;
+    pthread_mutex_unlock(&ctx->queueMutex);
+    /* Wake up sleeping threads */
+    pthread_cond_broadcast(&ctx->queuePushCond);
+    pthread_cond_broadcast(&ctx->queuePopCond);
+    /* Join all of the threads */
+    {   size_t i;
+        for (i = 0; i < ctx->numThreads; ++i) {
+            pthread_join(ctx->threads[i], NULL);
+    }   }
+}
+
+void POOL_free(POOL_ctx *ctx) {
+    if (!ctx) { return; }
+    POOL_join(ctx);
+    pthread_mutex_destroy(&ctx->queueMutex);
+    pthread_cond_destroy(&ctx->queuePushCond);
+    pthread_cond_destroy(&ctx->queuePopCond);
+    if (ctx->queue) free(ctx->queue);
+    if (ctx->threads) free(ctx->threads);
+    free(ctx);
+}
+
+void POOL_add(void *ctxVoid, POOL_function function, void *opaque) {
+    POOL_ctx *ctx = (POOL_ctx *)ctxVoid;
+    if (!ctx) { return; }
+
+    pthread_mutex_lock(&ctx->queueMutex);
+    {   POOL_job const job = {function, opaque};
+        /* Wait until there is space in the queue for the new job */
+        size_t newTail = (ctx->queueTail + 1) % ctx->queueSize;
+        while (ctx->queueHead == newTail && !ctx->shutdown) {
+          pthread_cond_wait(&ctx->queuePushCond, &ctx->queueMutex);
+          newTail = (ctx->queueTail + 1) % ctx->queueSize;
+        }
+        /* The queue is still going => there is space */
+        if (!ctx->shutdown) {
+            ctx->queue[ctx->queueTail] = job;
+            ctx->queueTail = newTail;
+        }
+    }
+    pthread_mutex_unlock(&ctx->queueMutex);
+    pthread_cond_signal(&ctx->queuePopCond);
+}
+
+#else  /* ZSTD_MULTITHREAD  not defined */
+/* No multi-threading support */
+
+/* We don't need any data, but if it is empty malloc() might return NULL. */
+struct POOL_ctx_s {
+  int data;
+};
+
+POOL_ctx *POOL_create(size_t numThreads, size_t queueSize) {
+  (void)numThreads;
+  (void)queueSize;
+  return (POOL_ctx *)malloc(sizeof(POOL_ctx));
+}
+
+void POOL_free(POOL_ctx *ctx) {
+  if (ctx) free(ctx);
+}
+
+void POOL_add(void *ctx, POOL_function function, void *opaque) {
+  (void)ctx;
+  function(opaque);
+}
+
+#endif  /* ZSTD_MULTITHREAD */
--- a/lib/common/pool.h
+++ b/lib/common/pool.h
@ -0,0 +1,46 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#ifndef POOL_H
+#define POOL_H
+
+#include <stddef.h>   /* size_t */
+
+typedef struct POOL_ctx_s POOL_ctx;
+
+/*! POOL_create() :
+    Create a thread pool with at most `numThreads` threads.
+    `numThreads` must be at least 1.
+    The maximum number of queued jobs before blocking is `queueSize`.
+    `queueSize` must be at least 1.
+    @return : The POOL_ctx pointer on success else NULL.
+*/
+POOL_ctx *POOL_create(size_t numThreads, size_t queueSize);
+
+/*! POOL_free() :
+    Free a thread pool returned by POOL_create().
+*/
+void POOL_free(POOL_ctx *ctx);
+
+/*! POOL_function :
+    The function type that can be added to a thread pool.
+*/
+typedef void (*POOL_function)(void *);
+/*! POOL_add_function :
+    The function type for a generic thread pool add function.
+*/
+typedef void (*POOL_add_function)(void *, POOL_function, void *);
+
+/*! POOL_add() :
+    Add the job `function(opaque)` to the thread pool.
+    Possibly blocks until there is room in the queue.
+    Note : The function may be executed asynchronously, so `opaque` must live until the function has been completed.
+*/
+void POOL_add(void *ctx, POOL_function function, void *opaque);
+
+#endif
--- a/lib/common/threading.c
+++ b/lib/common/threading.c
@ -0,0 +1,79 @@
+
+/**
+ * Copyright (c) 2016 Tino Reichardt
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * You can contact the author at:
+ * - zstdmt source repository: https://github.com/mcmilk/zstdmt
+ */
+
+/**
+ * This file will hold wrapper for systems, which do not support pthreads
+ */
+
+/* ======   Compiler specifics   ====== */
+#if defined(_MSC_VER)
+#  pragma warning(disable : 4206)        /* disable: C4206: translation unit is empty (when ZSTD_MULTITHREAD is not defined) */
+#endif
+
+
+#if defined(ZSTD_MULTITHREAD) && defined(_WIN32)
+
+/**
+ * Windows minimalist Pthread Wrapper, based on :
+ * http://www.cse.wustl.edu/~schmidt/win32-cv-1.html
+ */
+
+
+/* ===  Dependencies  === */
+#include <process.h>
+#include <errno.h>
+#include "threading.h"
+
+
+/* ===  Implementation  === */
+
+static unsigned __stdcall worker(void *arg)
+{
+    pthread_t* const thread = (pthread_t*) arg;
+    thread->arg = thread->start_routine(thread->arg);
+    return 0;
+}
+
+int pthread_create(pthread_t* thread, const void* unused,
+            void* (*start_routine) (void*), void* arg)
+{
+    (void)unused;
+    thread->arg = arg;
+    thread->start_routine = start_routine;
+    thread->handle = (HANDLE) _beginthreadex(NULL, 0, worker, thread, 0, NULL);
+
+    if (!thread->handle)
+        return errno;
+    else
+        return 0;
+}
+
+int _pthread_join(pthread_t * thread, void **value_ptr)
+{
+    DWORD result;
+
+    if (!thread->handle) return 0;
+
+    result = WaitForSingleObject(thread->handle, INFINITE);
+    switch (result) {
+    case WAIT_OBJECT_0:
+        if (value_ptr) *value_ptr = thread->arg;
+        return 0;
+    case WAIT_ABANDONED:
+        return EINVAL;
+    default:
+        return GetLastError();
+    }
+}
+
+#endif   /* ZSTD_MULTITHREAD */
--- a/lib/common/threading.h
+++ b/lib/common/threading.h
@ -0,0 +1,104 @@
+
+/**
+ * Copyright (c) 2016 Tino Reichardt
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * You can contact the author at:
+ * - zstdmt source repository: https://github.com/mcmilk/zstdmt
+ */
+
+#ifndef THREADING_H_938743
+#define THREADING_H_938743
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+#if defined(ZSTD_MULTITHREAD) && defined(_WIN32)
+
+/**
+ * Windows minimalist Pthread Wrapper, based on :
+ * http://www.cse.wustl.edu/~schmidt/win32-cv-1.html
+ */
+#ifdef WINVER
+#  undef WINVER
+#endif
+#define WINVER       0x0600
+
+#ifdef _WIN32_WINNT
+#  undef _WIN32_WINNT
+#endif
+#define _WIN32_WINNT 0x0600
+
+#ifndef WIN32_LEAN_AND_MEAN
+#  define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>
+
+/* mutex */
+#define pthread_mutex_t           CRITICAL_SECTION
+#define pthread_mutex_init(a,b)   InitializeCriticalSection((a))
+#define pthread_mutex_destroy(a)  DeleteCriticalSection((a))
+#define pthread_mutex_lock(a)     EnterCriticalSection((a))
+#define pthread_mutex_unlock(a)   LeaveCriticalSection((a))
+
+/* condition variable */
+#define pthread_cond_t             CONDITION_VARIABLE
+#define pthread_cond_init(a, b)    InitializeConditionVariable((a))
+#define pthread_cond_destroy(a)    /* No delete */
+#define pthread_cond_wait(a, b)    SleepConditionVariableCS((a), (b), INFINITE)
+#define pthread_cond_signal(a)     WakeConditionVariable((a))
+#define pthread_cond_broadcast(a)  WakeAllConditionVariable((a))
+
+/* pthread_create() and pthread_join() */
+typedef struct {
+    HANDLE handle;
+    void* (*start_routine)(void*);
+    void* arg;
+} pthread_t;
+
+int pthread_create(pthread_t* thread, const void* unused,
+                   void* (*start_routine) (void*), void* arg);
+
+#define pthread_join(a, b) _pthread_join(&(a), (b))
+int _pthread_join(pthread_t* thread, void** value_ptr);
+
+/**
+ * add here more wrappers as required
+ */
+
+
+#elif defined(ZSTD_MULTITHREAD)   /* posix assumed ; need a better detection mathod */
+/* ===   POSIX Systems   === */
+#  include <pthread.h>
+
+#else  /* ZSTD_MULTITHREAD not defined */
+/* No multithreading support */
+
+#define pthread_mutex_t int   /* #define rather than typedef, as sometimes pthread support is implicit, resulting in duplicated symbols */
+#define pthread_mutex_init(a,b)
+#define pthread_mutex_destroy(a)
+#define pthread_mutex_lock(a)
+#define pthread_mutex_unlock(a)
+
+#define pthread_cond_t int
+#define pthread_cond_init(a,b)
+#define pthread_cond_destroy(a)
+#define pthread_cond_wait(a,b)
+#define pthread_cond_signal(a)
+#define pthread_cond_broadcast(a)
+
+/* do not use pthread_t */
+
+#endif /* ZSTD_MULTITHREAD */
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* THREADING_H_938743 */
--- a/lib/common/zstd_internal.h
+++ b/lib/common/zstd_internal.h
@ -267,4 +267,13 @@ MEM_STATIC U32 ZSTD_highbit32(U32 val)
 }


+/* hidden functions */
+
+/* ZSTD_invalidateRepCodes() :
+ * ensures next compression will not use repcodes from previous block.
+ * Note : only works with regular variant;
+ *        do not use with extDict variant ! */
+void ZSTD_invalidateRepCodes(ZSTD_CCtx* cctx);
+
+
 #endif   /* ZSTD_CCOMMON_H_MODULE */
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@ -60,10 +60,11 @@ struct ZSTD_CCtx_s {
    U32   nextToUpdate;     /* index from which to continue dictionary update */
    U32   nextToUpdate3;    /* index from which to continue dictionary update */
    U32   hashLog3;         /* dispatch table : larger == faster, more memory */
-    U32   loadedDictEnd;
+    U32   loadedDictEnd;    /* index of end of dictionary */
+    U32   forceWindow;      /* force back-references to respect limit of 1<<wLog, even for dictionary */
    ZSTD_compressionStage_e stage;
    U32   rep[ZSTD_REP_NUM];
-    U32   savedRep[ZSTD_REP_NUM];
+    U32   repToConfirm[ZSTD_REP_NUM];
    U32   dictID;
    ZSTD_parameters params;
    void* workSpace;
@ -100,7 +101,7 @@ ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
    cctx = (ZSTD_CCtx*) ZSTD_malloc(sizeof(ZSTD_CCtx), customMem);
    if (!cctx) return NULL;
    memset(cctx, 0, sizeof(ZSTD_CCtx));
-    memcpy(&(cctx->customMem), &customMem, sizeof(customMem));
+    cctx->customMem = customMem;
    return cctx;
 }

@ -118,6 +119,15 @@ size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx)
    return sizeof(*cctx) + cctx->workSpaceSize;
 }

+size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter param, unsigned value)
+{
+    switch(param)
+    {
+    case ZSTD_p_forceWindow : cctx->forceWindow = value>0; cctx->loadedDictEnd = 0; return 0;
+    default: return ERROR(parameter_unknown);
+    }
+}
+
 const seqStore_t* ZSTD_getSeqStore(const ZSTD_CCtx* ctx)   /* hidden interface */
 {
    return &(ctx->seqStore);
@ -317,6 +327,14 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
    }
 }

+/* ZSTD_invalidateRepCodes() :
+ * ensures next compression will not use repcodes from previous block.
+ * Note : only works with regular variant;
+ *        do not use with extDict variant ! */
+void ZSTD_invalidateRepCodes(ZSTD_CCtx* cctx) {
+    int i;
+    for (i=0; i<ZSTD_REP_NUM; i++) cctx->rep[i] = 0;
+}

 /*! ZSTD_copyCCtx() :
 *   Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
@ -734,12 +752,19 @@ _check_compressibility:
      if ((size_t)(op-ostart) >= maxCSize) return 0; }

    /* confirm repcodes */
-    { int i; for (i=0; i<ZSTD_REP_NUM; i++) zc->rep[i] = zc->savedRep[i]; }
+    { int i; for (i=0; i<ZSTD_REP_NUM; i++) zc->rep[i] = zc->repToConfirm[i]; }

    return op - ostart;
 }


+#if 0 /* for debug */
+#  define STORESEQ_DEBUG
+#include <stdio.h>   /* fprintf */
+U32 g_startDebug = 0;
+const BYTE* g_start = NULL;
+#endif
+
 /*! ZSTD_storeSeq() :
    Store a sequence (literal length, literals, offset code and match length code) into seqStore_t.
    `offsetCode` : distance to match, or 0 == repCode.
@ -747,13 +772,14 @@ _check_compressibility:
 */
 MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const void* literals, U32 offsetCode, size_t matchCode)
 {
-#if 0  /* for debug */
-    static const BYTE* g_start = NULL;
-    const U32 pos = (U32)((const BYTE*)literals - g_start);
-    if (g_start==NULL) g_start = (const BYTE*)literals;
-    //if ((pos > 1) && (pos < 50000))
-        printf("Cpos %6u :%5u literals & match %3u bytes at distance %6u \n",
-               pos, (U32)litLength, (U32)matchCode+MINMATCH, (U32)offsetCode);
+#ifdef STORESEQ_DEBUG
+    if (g_startDebug) {
+        const U32 pos = (U32)((const BYTE*)literals - g_start);
+        if (g_start==NULL) g_start = (const BYTE*)literals;
+        if ((pos > 1895000) && (pos < 1895300))
+            fprintf(stderr, "Cpos %6u :%5u literals & match %3u bytes at distance %6u \n",
+                   pos, (U32)litLength, (U32)matchCode+MINMATCH, (U32)offsetCode);
+    }
 #endif
    /* copy Literals */
    ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);
@ -1003,8 +1029,8 @@ void ZSTD_compressBlock_fast_generic(ZSTD_CCtx* cctx,
    }   }   }

    /* save reps for next block */
-    cctx->savedRep[0] = offset_1 ? offset_1 : offsetSaved;
-    cctx->savedRep[1] = offset_2 ? offset_2 : offsetSaved;
+    cctx->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
+    cctx->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;

    /* Last Literals */
    {   size_t const lastLLSize = iend - anchor;
@ -1118,7 +1144,7 @@ static void ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx* ctx,
    }   }   }

    /* save reps for next block */
-    ctx->savedRep[0] = offset_1; ctx->savedRep[1] = offset_2;
+    ctx->repToConfirm[0] = offset_1; ctx->repToConfirm[1] = offset_2;

    /* Last Literals */
    {   size_t const lastLLSize = iend - anchor;
@ -1272,8 +1298,8 @@ void ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx* cctx,
    }   }   }

    /* save reps for next block */
-    cctx->savedRep[0] = offset_1 ? offset_1 : offsetSaved;
-    cctx->savedRep[1] = offset_2 ? offset_2 : offsetSaved;
+    cctx->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
+    cctx->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;

    /* Last Literals */
    {   size_t const lastLLSize = iend - anchor;
@ -1422,7 +1448,7 @@ static void ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_CCtx* ctx,
    }   }   }

    /* save reps for next block */
-    ctx->savedRep[0] = offset_1; ctx->savedRep[1] = offset_2;
+    ctx->repToConfirm[0] = offset_1; ctx->repToConfirm[1] = offset_2;

    /* Last Literals */
    {   size_t const lastLLSize = iend - anchor;
@ -1954,8 +1980,8 @@ _storeSequence:
    }   }

    /* Save reps for next block */
-    ctx->savedRep[0] = offset_1 ? offset_1 : savedOffset;
-    ctx->savedRep[1] = offset_2 ? offset_2 : savedOffset;
+    ctx->repToConfirm[0] = offset_1 ? offset_1 : savedOffset;
+    ctx->repToConfirm[1] = offset_2 ? offset_2 : savedOffset;

    /* Last Literals */
    {   size_t const lastLLSize = iend - anchor;
@ -2149,7 +2175,7 @@ _storeSequence:
    }   }

    /* Save reps for next block */
-    ctx->savedRep[0] = offset_1; ctx->savedRep[1] = offset_2;
+    ctx->repToConfirm[0] = offset_1; ctx->repToConfirm[1] = offset_2;

    /* Last Literals */
    {   size_t const lastLLSize = iend - anchor;
@ -2408,12 +2434,14 @@ static size_t ZSTD_compressContinue_internal (ZSTD_CCtx* cctx,

    cctx->nextSrc = ip + srcSize;

-    {   size_t const cSize = frame ?
+    if (srcSize) {
+        size_t const cSize = frame ?
                             ZSTD_compress_generic (cctx, dst, dstCapacity, src, srcSize, lastFrameChunk) :
                             ZSTD_compressBlock_internal (cctx, dst, dstCapacity, src, srcSize);
        if (ZSTD_isError(cSize)) return cSize;
        return cSize + fhSize;
-    }
+    } else
+        return fhSize;
 }


@ -2449,7 +2477,7 @@ static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx* zc, const void* src, size_t
    zc->dictBase = zc->base;
    zc->base += ip - zc->nextSrc;
    zc->nextToUpdate = zc->dictLimit;
-    zc->loadedDictEnd = (U32)(iend - zc->base);
+    zc->loadedDictEnd = zc->forceWindow ? 0 : (U32)(iend - zc->base);

    zc->nextSrc = iend;
    if (srcSize <= HASH_READ_SIZE) return 0;
@ -2593,7 +2621,6 @@ static size_t ZSTD_compress_insertDictionary(ZSTD_CCtx* zc, const void* dict, si
    }
 }

-
 /*! ZSTD_compressBegin_internal() :
 *   @return : 0, or an error code */
 static size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
@ -2625,9 +2652,9 @@ size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t di
 }


-size_t ZSTD_compressBegin(ZSTD_CCtx* zc, int compressionLevel)
+size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel)
 {
-    return ZSTD_compressBegin_usingDict(zc, NULL, 0, compressionLevel);
+    return ZSTD_compressBegin_usingDict(cctx, NULL, 0, compressionLevel);
 }


@ -2815,7 +2842,7 @@ static ZSTD_parameters ZSTD_getParamsFromCDict(const ZSTD_CDict* cdict) {
    return ZSTD_getParamsFromCCtx(cdict->refContext);
 }

-size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict, U64 pledgedSrcSize)
+size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict, unsigned long long pledgedSrcSize)
 {
    if (cdict->dictContentSize) CHECK_F(ZSTD_copyCCtx(cctx, cdict->refContext, pledgedSrcSize))
    else CHECK_F(ZSTD_compressBegin_advanced(cctx, NULL, 0, cdict->refContext->params, pledgedSrcSize));
@ -2951,7 +2978,7 @@ size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
        if (zcs->outBuff == NULL) return ERROR(memory_allocation);
    }

-    if (dict) {
+    if (dict && dictSize >= 8) {
        ZSTD_freeCDict(zcs->cdictLocal);
        zcs->cdictLocal = ZSTD_createCDict_advanced(dict, dictSize, 0, params, zcs->customMem);
        if (zcs->cdictLocal == NULL) return ERROR(memory_allocation);
--- a/lib/compress/zstd_opt.h
+++ b/lib/compress/zstd_opt.h
@ -38,7 +38,7 @@ MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr, const BYTE* src, size_t src

    ssPtr->cachedLiterals = NULL;
    ssPtr->cachedPrice = ssPtr->cachedLitLength = 0;
-    ssPtr->staticPrices = 0; 
+    ssPtr->staticPrices = 0;

    if (ssPtr->litLengthSum == 0) {
        if (srcSize <= 1024) ssPtr->staticPrices = 1;
@ -56,7 +56,7 @@ MEM_STATIC void ZSTD_rescaleFreqs(seqStore_t* ssPtr, const BYTE* src, size_t src

        for (u=0; u<=MaxLit; u++) {
            ssPtr->litFreq[u] = 1 + (ssPtr->litFreq[u]>>ZSTD_FREQ_DIV);
-            ssPtr->litSum += ssPtr->litFreq[u]; 
+            ssPtr->litSum += ssPtr->litFreq[u];
        }
        for (u=0; u<=MaxLL; u++)
            ssPtr->litLengthFreq[u] = 1;
@ -634,7 +634,7 @@ _storeSequence:   /* cur, last_pos, best_mlen, best_off have to be set */
    }    }   /* for (cur=0; cur < last_pos; ) */

    /* Save reps for next block */
-    { int i; for (i=0; i<ZSTD_REP_NUM; i++) ctx->savedRep[i] = rep[i]; }
+    { int i; for (i=0; i<ZSTD_REP_NUM; i++) ctx->repToConfirm[i] = rep[i]; }

    /* Last Literals */
    {   size_t const lastLLSize = iend - anchor;
@ -907,7 +907,7 @@ _storeSequence:   /* cur, last_pos, best_mlen, best_off have to be set */
    }    }   /* for (cur=0; cur < last_pos; ) */

    /* Save reps for next block */
-    { int i; for (i=0; i<ZSTD_REP_NUM; i++) ctx->savedRep[i] = rep[i]; }
+    { int i; for (i=0; i<ZSTD_REP_NUM; i++) ctx->repToConfirm[i] = rep[i]; }

    /* Last Literals */
    {   size_t lastLLSize = iend - anchor;
--- a/lib/compress/zstdmt_compress.c
+++ b/lib/compress/zstdmt_compress.c
@ -0,0 +1,732 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+
+/* ======   Tuning parameters   ====== */
+#define ZSTDMT_NBTHREADS_MAX 128
+
+
+/* ======   Compiler specifics   ====== */
+#if defined(_MSC_VER)
+#  pragma warning(disable : 4204)        /* disable: C4204: non-constant aggregate initializer */
+#endif
+
+
+/* ======   Dependencies   ====== */
+#include <stdlib.h>   /* malloc */
+#include <string.h>   /* memcpy */
+#include <pool.h>     /* threadpool */
+#include "threading.h"  /* mutex */
+#include "zstd_internal.h"   /* MIN, ERROR, ZSTD_*, ZSTD_highbit32 */
+#include "zstdmt_compress.h"
+#define XXH_STATIC_LINKING_ONLY   /* XXH64_state_t */
+#include "xxhash.h"
+
+
+/* ======   Debug   ====== */
+#if 0
+
+#  include <stdio.h>
+#  include <unistd.h>
+#  include <sys/times.h>
+   static unsigned g_debugLevel = 3;
+#  define DEBUGLOGRAW(l, ...) if (l<=g_debugLevel) { fprintf(stderr, __VA_ARGS__); }
+#  define DEBUGLOG(l, ...) if (l<=g_debugLevel) { fprintf(stderr, __FILE__ ": "); fprintf(stderr, __VA_ARGS__); fprintf(stderr, " \n"); }
+
+#  define DEBUG_PRINTHEX(l,p,n) { \
+    unsigned debug_u;                   \
+    for (debug_u=0; debug_u<(n); debug_u++)           \
+        DEBUGLOGRAW(l, "%02X ", ((const unsigned char*)(p))[debug_u]); \
+    DEBUGLOGRAW(l, " \n");       \
+}
+
+static unsigned long long GetCurrentClockTimeMicroseconds()
+{
+   static clock_t _ticksPerSecond = 0;
+   if (_ticksPerSecond <= 0) _ticksPerSecond = sysconf(_SC_CLK_TCK);
+
+   struct tms junk; clock_t newTicks = (clock_t) times(&junk);
+   return ((((unsigned long long)newTicks)*(1000000))/_ticksPerSecond);
+}
+
+#define MUTEX_WAIT_TIME_DLEVEL 5
+#define PTHREAD_MUTEX_LOCK(mutex) \
+if (g_debugLevel>=MUTEX_WAIT_TIME_DLEVEL) { \
+   unsigned long long beforeTime = GetCurrentClockTimeMicroseconds(); \
+   pthread_mutex_lock(mutex); \
+   unsigned long long afterTime = GetCurrentClockTimeMicroseconds(); \
+   unsigned long long elapsedTime = (afterTime-beforeTime); \
+   if (elapsedTime > 1000) {  /* or whatever threshold you like; I'm using 1 millisecond here */ \
+      DEBUGLOG(MUTEX_WAIT_TIME_DLEVEL, "Thread took %llu microseconds to acquire mutex %s \n", \
+               elapsedTime, #mutex); \
+  } \
+} else pthread_mutex_lock(mutex);
+
+#else
+
+#  define DEBUGLOG(l, ...)      {}    /* disabled */
+#  define PTHREAD_MUTEX_LOCK(m) pthread_mutex_lock(m)
+#  define DEBUG_PRINTHEX(l,p,n) {}
+
+#endif
+
+
+/* =====   Buffer Pool   ===== */
+
+typedef struct buffer_s {
+    void* start;
+    size_t size;
+} buffer_t;
+
+static const buffer_t g_nullBuffer = { NULL, 0 };
+
+typedef struct ZSTDMT_bufferPool_s {
+    unsigned totalBuffers;
+    unsigned nbBuffers;
+    buffer_t bTable[1];   /* variable size */
+} ZSTDMT_bufferPool;
+
+static ZSTDMT_bufferPool* ZSTDMT_createBufferPool(unsigned nbThreads)
+{
+    unsigned const maxNbBuffers = 2*nbThreads + 2;
+    ZSTDMT_bufferPool* const bufPool = (ZSTDMT_bufferPool*)calloc(1, sizeof(ZSTDMT_bufferPool) + (maxNbBuffers-1) * sizeof(buffer_t));
+    if (bufPool==NULL) return NULL;
+    bufPool->totalBuffers = maxNbBuffers;
+    bufPool->nbBuffers = 0;
+    return bufPool;
+}
+
+static void ZSTDMT_freeBufferPool(ZSTDMT_bufferPool* bufPool)
+{
+    unsigned u;
+    if (!bufPool) return;   /* compatibility with free on NULL */
+    for (u=0; u<bufPool->totalBuffers; u++)
+        free(bufPool->bTable[u].start);
+    free(bufPool);
+}
+
+/* assumption : invocation from main thread only ! */
+static buffer_t ZSTDMT_getBuffer(ZSTDMT_bufferPool* pool, size_t bSize)
+{
+    if (pool->nbBuffers) {   /* try to use an existing buffer */
+        buffer_t const buf = pool->bTable[--(pool->nbBuffers)];
+        size_t const availBufferSize = buf.size;
+        if ((availBufferSize >= bSize) & (availBufferSize <= 10*bSize))   /* large enough, but not too much */
+            return buf;
+        free(buf.start);   /* size conditions not respected : scratch this buffer and create a new one */
+    }
+    /* create new buffer */
+    {   buffer_t buffer;
+        void* const start = malloc(bSize);
+        if (start==NULL) bSize = 0;
+        buffer.start = start;   /* note : start can be NULL if malloc fails ! */
+        buffer.size = bSize;
+        return buffer;
+    }
+}
+
+/* store buffer for later re-use, up to pool capacity */
+static void ZSTDMT_releaseBuffer(ZSTDMT_bufferPool* pool, buffer_t buf)
+{
+    if (buf.start == NULL) return;   /* release on NULL */
+    if (pool->nbBuffers < pool->totalBuffers) {
+        pool->bTable[pool->nbBuffers++] = buf;   /* store for later re-use */
+        return;
+    }
+    /* Reached bufferPool capacity (should not happen) */
+    free(buf.start);
+}
+
+
+/* =====   CCtx Pool   ===== */
+
+typedef struct {
+    unsigned totalCCtx;
+    unsigned availCCtx;
+    ZSTD_CCtx* cctx[1];   /* variable size */
+} ZSTDMT_CCtxPool;
+
+/* assumption : CCtxPool invocation only from main thread */
+
+/* note : all CCtx borrowed from the pool should be released back to the pool _before_ freeing the pool */
+static void ZSTDMT_freeCCtxPool(ZSTDMT_CCtxPool* pool)
+{
+    unsigned u;
+    for (u=0; u<pool->totalCCtx; u++)
+        ZSTD_freeCCtx(pool->cctx[u]);  /* note : compatible with free on NULL */
+    free(pool);
+}
+
+/* ZSTDMT_createCCtxPool() :
+ * implies nbThreads >= 1 , checked by caller ZSTDMT_createCCtx() */
+static ZSTDMT_CCtxPool* ZSTDMT_createCCtxPool(unsigned nbThreads)
+{
+    ZSTDMT_CCtxPool* const cctxPool = (ZSTDMT_CCtxPool*) calloc(1, sizeof(ZSTDMT_CCtxPool) + (nbThreads-1)*sizeof(ZSTD_CCtx*));
+    if (!cctxPool) return NULL;
+    cctxPool->totalCCtx = nbThreads;
+    cctxPool->availCCtx = 1;   /* at least one cctx for single-thread mode */
+    cctxPool->cctx[0] = ZSTD_createCCtx();
+    if (!cctxPool->cctx[0]) { ZSTDMT_freeCCtxPool(cctxPool); return NULL; }
+    DEBUGLOG(1, "cctxPool created, with %u threads", nbThreads);
+    return cctxPool;
+}
+
+static ZSTD_CCtx* ZSTDMT_getCCtx(ZSTDMT_CCtxPool* pool)
+{
+    if (pool->availCCtx) {
+        pool->availCCtx--;
+        return pool->cctx[pool->availCCtx];
+    }
+    return ZSTD_createCCtx();   /* note : can be NULL, when creation fails ! */
+}
+
+static void ZSTDMT_releaseCCtx(ZSTDMT_CCtxPool* pool, ZSTD_CCtx* cctx)
+{
+    if (cctx==NULL) return;   /* compatibility with release on NULL */
+    if (pool->availCCtx < pool->totalCCtx)
+        pool->cctx[pool->availCCtx++] = cctx;
+    else
+        /* pool overflow : should not happen, since totalCCtx==nbThreads */
+        ZSTD_freeCCtx(cctx);
+}
+
+
+/* =====   Thread worker   ===== */
+
+typedef struct {
+    buffer_t buffer;
+    size_t filled;
+} inBuff_t;
+
+typedef struct {
+    ZSTD_CCtx* cctx;
+    buffer_t src;
+    const void* srcStart;
+    size_t   srcSize;
+    size_t   dictSize;
+    buffer_t dstBuff;
+    size_t   cSize;
+    size_t   dstFlushed;
+    unsigned firstChunk;
+    unsigned lastChunk;
+    unsigned jobCompleted;
+    unsigned jobScanned;
+    pthread_mutex_t* jobCompleted_mutex;
+    pthread_cond_t* jobCompleted_cond;
+    ZSTD_parameters params;
+    ZSTD_CDict* cdict;
+    unsigned long long fullFrameSize;
+} ZSTDMT_jobDescription;
+
+/* ZSTDMT_compressChunk() : POOL_function type */
+void ZSTDMT_compressChunk(void* jobDescription)
+{
+    ZSTDMT_jobDescription* const job = (ZSTDMT_jobDescription*)jobDescription;
+    const void* const src = (const char*)job->srcStart + job->dictSize;
+    buffer_t const dstBuff = job->dstBuff;
+    DEBUGLOG(3, "job (first:%u) (last:%u) : dictSize %u, srcSize %u", job->firstChunk, job->lastChunk, (U32)job->dictSize, (U32)job->srcSize);
+    if (job->cdict) {
+        size_t const initError = ZSTD_compressBegin_usingCDict(job->cctx, job->cdict, job->fullFrameSize);
+        if (job->cdict) DEBUGLOG(3, "using CDict ");
+        if (ZSTD_isError(initError)) { job->cSize = initError; goto _endJob; }
+    } else {
+        size_t const initError = ZSTD_compressBegin_advanced(job->cctx, job->srcStart, job->dictSize, job->params, job->fullFrameSize);
+        if (ZSTD_isError(initError)) { job->cSize = initError; goto _endJob; }
+        ZSTD_setCCtxParameter(job->cctx, ZSTD_p_forceWindow, 1);
+    }
+    if (!job->firstChunk) {  /* flush frame header */
+        size_t const hSize = ZSTD_compressContinue(job->cctx, dstBuff.start, dstBuff.size, src, 0);
+        if (ZSTD_isError(hSize)) { job->cSize = hSize; goto _endJob; }
+        ZSTD_invalidateRepCodes(job->cctx);
+    }
+
+    DEBUGLOG(4, "Compressing : ");
+    DEBUG_PRINTHEX(4, job->srcStart, 12);
+    job->cSize = (job->lastChunk) ?   /* last chunk signal */
+                 ZSTD_compressEnd     (job->cctx, dstBuff.start, dstBuff.size, src, job->srcSize) :
+                 ZSTD_compressContinue(job->cctx, dstBuff.start, dstBuff.size, src, job->srcSize);
+    DEBUGLOG(3, "compressed %u bytes into %u bytes   (first:%u) (last:%u)", (unsigned)job->srcSize, (unsigned)job->cSize, job->firstChunk, job->lastChunk);
+
+_endJob:
+    PTHREAD_MUTEX_LOCK(job->jobCompleted_mutex);
+    job->jobCompleted = 1;
+    job->jobScanned = 0;
+    pthread_cond_signal(job->jobCompleted_cond);
+    pthread_mutex_unlock(job->jobCompleted_mutex);
+}
+
+
+/* ------------------------------------------ */
+/* =====   Multi-threaded compression   ===== */
+/* ------------------------------------------ */
+
+struct ZSTDMT_CCtx_s {
+    POOL_ctx* factory;
+    ZSTDMT_bufferPool* buffPool;
+    ZSTDMT_CCtxPool* cctxPool;
+    pthread_mutex_t jobCompleted_mutex;
+    pthread_cond_t jobCompleted_cond;
+    size_t targetSectionSize;
+    size_t inBuffSize;
+    size_t dictSize;
+    size_t targetDictSize;
+    inBuff_t inBuff;
+    ZSTD_parameters params;
+    XXH64_state_t xxhState;
+    unsigned nbThreads;
+    unsigned jobIDMask;
+    unsigned doneJobID;
+    unsigned nextJobID;
+    unsigned frameEnded;
+    unsigned allJobsCompleted;
+    unsigned overlapWrLog;
+    unsigned long long frameContentSize;
+    size_t sectionSize;
+    ZSTD_CDict* cdict;
+    ZSTD_CStream* cstream;
+    ZSTDMT_jobDescription jobs[1];   /* variable size (must lies at the end) */
+};
+
+ZSTDMT_CCtx *ZSTDMT_createCCtx(unsigned nbThreads)
+{
+    ZSTDMT_CCtx* cctx;
+    U32 const minNbJobs = nbThreads + 2;
+    U32 const nbJobsLog2 = ZSTD_highbit32(minNbJobs) + 1;
+    U32 const nbJobs = 1 << nbJobsLog2;
+    DEBUGLOG(5, "nbThreads : %u  ; minNbJobs : %u ;  nbJobsLog2 : %u ;  nbJobs : %u  \n",
+            nbThreads, minNbJobs, nbJobsLog2, nbJobs);
+    if ((nbThreads < 1) | (nbThreads > ZSTDMT_NBTHREADS_MAX)) return NULL;
+    cctx = (ZSTDMT_CCtx*) calloc(1, sizeof(ZSTDMT_CCtx) + nbJobs*sizeof(ZSTDMT_jobDescription));
+    if (!cctx) return NULL;
+    cctx->nbThreads = nbThreads;
+    cctx->jobIDMask = nbJobs - 1;
+    cctx->allJobsCompleted = 1;
+    cctx->sectionSize = 0;
+    cctx->overlapWrLog = 3;
+    cctx->factory = POOL_create(nbThreads, 1);
+    cctx->buffPool = ZSTDMT_createBufferPool(nbThreads);
+    cctx->cctxPool = ZSTDMT_createCCtxPool(nbThreads);
+    if (!cctx->factory | !cctx->buffPool | !cctx->cctxPool) {  /* one object was not created */
+        ZSTDMT_freeCCtx(cctx);
+        return NULL;
+    }
+    if (nbThreads==1) {
+        cctx->cstream = ZSTD_createCStream();
+        if (!cctx->cstream) {
+            ZSTDMT_freeCCtx(cctx); return NULL;
+    }   }
+    pthread_mutex_init(&cctx->jobCompleted_mutex, NULL);   /* Todo : check init function return */
+    pthread_cond_init(&cctx->jobCompleted_cond, NULL);
+    DEBUGLOG(4, "mt_cctx created, for %u threads \n", nbThreads);
+    return cctx;
+}
+
+/* ZSTDMT_releaseAllJobResources() :
+ * Ensure all workers are killed first. */
+static void ZSTDMT_releaseAllJobResources(ZSTDMT_CCtx* mtctx)
+{
+    unsigned jobID;
+    for (jobID=0; jobID <= mtctx->jobIDMask; jobID++) {
+        ZSTDMT_releaseBuffer(mtctx->buffPool, mtctx->jobs[jobID].dstBuff);
+        mtctx->jobs[jobID].dstBuff = g_nullBuffer;
+        ZSTDMT_releaseBuffer(mtctx->buffPool, mtctx->jobs[jobID].src);
+        mtctx->jobs[jobID].src = g_nullBuffer;
+        ZSTDMT_releaseCCtx(mtctx->cctxPool, mtctx->jobs[jobID].cctx);
+        mtctx->jobs[jobID].cctx = NULL;
+    }
+    memset(mtctx->jobs, 0, (mtctx->jobIDMask+1)*sizeof(ZSTDMT_jobDescription));
+    ZSTDMT_releaseBuffer(mtctx->buffPool, mtctx->inBuff.buffer);
+    mtctx->inBuff.buffer = g_nullBuffer;
+    mtctx->allJobsCompleted = 1;
+}
+
+size_t ZSTDMT_freeCCtx(ZSTDMT_CCtx* mtctx)
+{
+    if (mtctx==NULL) return 0;   /* compatible with free on NULL */
+    POOL_free(mtctx->factory);
+    if (!mtctx->allJobsCompleted) ZSTDMT_releaseAllJobResources(mtctx); /* stop workers first */
+    ZSTDMT_freeBufferPool(mtctx->buffPool);  /* release job resources into pools first */
+    ZSTDMT_freeCCtxPool(mtctx->cctxPool);
+    ZSTD_freeCDict(mtctx->cdict);
+    ZSTD_freeCStream(mtctx->cstream);
+    pthread_mutex_destroy(&mtctx->jobCompleted_mutex);
+    pthread_cond_destroy(&mtctx->jobCompleted_cond);
+    free(mtctx);
+    return 0;
+}
+
+size_t ZSTDMT_setMTCtxParameter(ZSTDMT_CCtx* mtctx, ZSDTMT_parameter parameter, unsigned value)
+{
+    switch(parameter)
+    {
+    case ZSTDMT_p_sectionSize :
+        mtctx->sectionSize = value;
+        return 0;
+    case ZSTDMT_p_overlapSectionRLog :
+        mtctx->overlapWrLog = value;
+        return 0;
+    default :
+        return ERROR(compressionParameter_unsupported);
+    }
+}
+
+
+/* ------------------------------------------ */
+/* =====   Multi-threaded compression   ===== */
+/* ------------------------------------------ */
+
+size_t ZSTDMT_compressCCtx(ZSTDMT_CCtx* mtctx,
+                           void* dst, size_t dstCapacity,
+                     const void* src, size_t srcSize,
+                           int compressionLevel)
+{
+    ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize, 0);
+    size_t const chunkTargetSize = (size_t)1 << (params.cParams.windowLog + 2);
+    unsigned const nbChunksMax = (unsigned)(srcSize / chunkTargetSize) + (srcSize < chunkTargetSize) /* min 1 */;
+    unsigned nbChunks = MIN(nbChunksMax, mtctx->nbThreads);
+    size_t const proposedChunkSize = (srcSize + (nbChunks-1)) / nbChunks;
+    size_t const avgChunkSize = ((proposedChunkSize & 0x1FFFF) < 0xFFFF) ? proposedChunkSize + 0xFFFF : proposedChunkSize;   /* avoid too small last block */
+    size_t remainingSrcSize = srcSize;
+    const char* const srcStart = (const char*)src;
+    size_t frameStartPos = 0;
+
+    DEBUGLOG(3, "windowLog : %2u => chunkTargetSize : %u bytes  ", params.cParams.windowLog, (U32)chunkTargetSize);
+    DEBUGLOG(2, "nbChunks  : %2u   (chunkSize : %u bytes)   ", nbChunks, (U32)avgChunkSize);
+    params.fParams.contentSizeFlag = 1;
+
+    if (nbChunks==1) {   /* fallback to single-thread mode */
+        ZSTD_CCtx* const cctx = mtctx->cctxPool->cctx[0];
+        return ZSTD_compressCCtx(cctx, dst, dstCapacity, src, srcSize, compressionLevel);
+    }
+
+    {   unsigned u;
+        for (u=0; u<nbChunks; u++) {
+            size_t const chunkSize = MIN(remainingSrcSize, avgChunkSize);
+            size_t const dstBufferCapacity = u ? ZSTD_compressBound(chunkSize) : dstCapacity;
+            buffer_t const dstAsBuffer = { dst, dstCapacity };
+            buffer_t const dstBuffer = u ? ZSTDMT_getBuffer(mtctx->buffPool, dstBufferCapacity) : dstAsBuffer;
+            ZSTD_CCtx* const cctx = ZSTDMT_getCCtx(mtctx->cctxPool);
+
+            if ((cctx==NULL) || (dstBuffer.start==NULL)) {
+                mtctx->jobs[u].cSize = ERROR(memory_allocation);   /* job result */
+                mtctx->jobs[u].jobCompleted = 1;
+                nbChunks = u+1;
+                break;   /* let's wait for previous jobs to complete, but don't start new ones */
+            }
+
+            mtctx->jobs[u].srcStart = srcStart + frameStartPos;
+            mtctx->jobs[u].srcSize = chunkSize;
+            mtctx->jobs[u].fullFrameSize = srcSize;
+            mtctx->jobs[u].params = params;
+            mtctx->jobs[u].dstBuff = dstBuffer;
+            mtctx->jobs[u].cctx = cctx;
+            mtctx->jobs[u].firstChunk = (u==0);
+            mtctx->jobs[u].lastChunk = (u==nbChunks-1);
+            mtctx->jobs[u].jobCompleted = 0;
+            mtctx->jobs[u].jobCompleted_mutex = &mtctx->jobCompleted_mutex;
+            mtctx->jobs[u].jobCompleted_cond = &mtctx->jobCompleted_cond;
+
+            DEBUGLOG(3, "posting job %u   (%u bytes)", u, (U32)chunkSize);
+            DEBUG_PRINTHEX(3, mtctx->jobs[u].srcStart, 12);
+            POOL_add(mtctx->factory, ZSTDMT_compressChunk, &mtctx->jobs[u]);
+
+            frameStartPos += chunkSize;
+            remainingSrcSize -= chunkSize;
+    }   }
+    /* note : since nbChunks <= nbThreads, all jobs should be running immediately in parallel */
+
+    {   unsigned chunkID;
+        size_t error = 0, dstPos = 0;
+        for (chunkID=0; chunkID<nbChunks; chunkID++) {
+            DEBUGLOG(3, "waiting for chunk %u ", chunkID);
+            PTHREAD_MUTEX_LOCK(&mtctx->jobCompleted_mutex);
+            while (mtctx->jobs[chunkID].jobCompleted==0) {
+                DEBUGLOG(4, "waiting for jobCompleted signal from chunk %u", chunkID);
+                pthread_cond_wait(&mtctx->jobCompleted_cond, &mtctx->jobCompleted_mutex);
+            }
+            pthread_mutex_unlock(&mtctx->jobCompleted_mutex);
+            DEBUGLOG(3, "ready to write chunk %u ", chunkID);
+
+            ZSTDMT_releaseCCtx(mtctx->cctxPool, mtctx->jobs[chunkID].cctx);
+            mtctx->jobs[chunkID].cctx = NULL;
+            mtctx->jobs[chunkID].srcStart = NULL;
+            {   size_t const cSize = mtctx->jobs[chunkID].cSize;
+                if (ZSTD_isError(cSize)) error = cSize;
+                if ((!error) && (dstPos + cSize > dstCapacity)) error = ERROR(dstSize_tooSmall);
+                if (chunkID) {   /* note : chunk 0 is already written directly into dst */
+                    if (!error) memcpy((char*)dst + dstPos, mtctx->jobs[chunkID].dstBuff.start, cSize);
+                    ZSTDMT_releaseBuffer(mtctx->buffPool, mtctx->jobs[chunkID].dstBuff);
+                    mtctx->jobs[chunkID].dstBuff = g_nullBuffer;
+                }
+                dstPos += cSize ;
+            }
+        }
+        if (!error) DEBUGLOG(3, "compressed size : %u  ", (U32)dstPos);
+        return error ? error : dstPos;
+    }
+
+}
+
+
+/* ====================================== */
+/* =======      Streaming API     ======= */
+/* ====================================== */
+
+static void ZSTDMT_waitForAllJobsCompleted(ZSTDMT_CCtx* zcs) {
+    while (zcs->doneJobID < zcs->nextJobID) {
+        unsigned const jobID = zcs->doneJobID & zcs->jobIDMask;
+        PTHREAD_MUTEX_LOCK(&zcs->jobCompleted_mutex);
+        while (zcs->jobs[jobID].jobCompleted==0) {
+            DEBUGLOG(4, "waiting for jobCompleted signal from chunk %u", zcs->doneJobID);   /* we want to block when waiting for data to flush */
+            pthread_cond_wait(&zcs->jobCompleted_cond, &zcs->jobCompleted_mutex);
+        }
+        pthread_mutex_unlock(&zcs->jobCompleted_mutex);
+        zcs->doneJobID++;
+    }
+}
+
+
+static size_t ZSTDMT_initCStream_internal(ZSTDMT_CCtx* zcs,
+                                    const void* dict, size_t dictSize, unsigned updateDict,
+                                    ZSTD_parameters params, unsigned long long pledgedSrcSize)
+{
+    ZSTD_customMem const cmem = { NULL, NULL, NULL };
+    DEBUGLOG(3, "Started new compression, with windowLog : %u", params.cParams.windowLog);
+    if (zcs->nbThreads==1) return ZSTD_initCStream_advanced(zcs->cstream, dict, dictSize, params, pledgedSrcSize);
+    if (zcs->allJobsCompleted == 0) {   /* previous job not correctly finished */
+        ZSTDMT_waitForAllJobsCompleted(zcs);
+        ZSTDMT_releaseAllJobResources(zcs);
+        zcs->allJobsCompleted = 1;
+    }
+    zcs->params = params;
+    if (updateDict) {
+        ZSTD_freeCDict(zcs->cdict); zcs->cdict = NULL;
+        if (dict && dictSize) {
+            zcs->cdict = ZSTD_createCDict_advanced(dict, dictSize, 0, params, cmem);
+            if (zcs->cdict == NULL) return ERROR(memory_allocation);
+    }   }
+    zcs->frameContentSize = pledgedSrcSize;
+    zcs->targetSectionSize = zcs->sectionSize ? zcs->sectionSize : (size_t)1 << (zcs->params.cParams.windowLog + 2);
+    zcs->targetSectionSize = MAX(ZSTDMT_SECTION_SIZE_MIN, zcs->targetSectionSize);
+    zcs->targetDictSize = zcs->overlapWrLog < 10 ? (size_t)1 << (zcs->params.cParams.windowLog - zcs->overlapWrLog) : 0;
+    zcs->inBuffSize = zcs->targetSectionSize + ((size_t)1 << zcs->params.cParams.windowLog) /* margin */ + zcs->targetDictSize;
+    zcs->inBuff.buffer = ZSTDMT_getBuffer(zcs->buffPool, zcs->inBuffSize);
+    if (zcs->inBuff.buffer.start == NULL) return ERROR(memory_allocation);
+    zcs->inBuff.filled = 0;
+    zcs->dictSize = 0;
+    zcs->doneJobID = 0;
+    zcs->nextJobID = 0;
+    zcs->frameEnded = 0;
+    zcs->allJobsCompleted = 0;
+    if (params.fParams.checksumFlag) XXH64_reset(&zcs->xxhState, 0);
+    return 0;
+}
+
+size_t ZSTDMT_initCStream_advanced(ZSTDMT_CCtx* zcs,
+                                const void* dict, size_t dictSize,
+                                ZSTD_parameters params, unsigned long long pledgedSrcSize)
+{
+    return ZSTDMT_initCStream_internal(zcs, dict, dictSize, 1, params, pledgedSrcSize);
+}
+
+/* ZSTDMT_resetCStream() :
+ * pledgedSrcSize is optional and can be zero == unknown */
+size_t ZSTDMT_resetCStream(ZSTDMT_CCtx* zcs, unsigned long long pledgedSrcSize)
+{
+    if (zcs->nbThreads==1) return ZSTD_resetCStream(zcs->cstream, pledgedSrcSize);
+    return ZSTDMT_initCStream_internal(zcs, NULL, 0, 0, zcs->params, pledgedSrcSize);
+}
+
+size_t ZSTDMT_initCStream(ZSTDMT_CCtx* zcs, int compressionLevel) {
+    ZSTD_parameters const params = ZSTD_getParams(compressionLevel, 0, 0);
+    return ZSTDMT_initCStream_internal(zcs, NULL, 0, 1, params, 0);
+}
+
+
+static size_t ZSTDMT_createCompressionJob(ZSTDMT_CCtx* zcs, size_t srcSize, unsigned endFrame)
+{
+    size_t const dstBufferCapacity = ZSTD_compressBound(srcSize);
+    buffer_t const dstBuffer = ZSTDMT_getBuffer(zcs->buffPool, dstBufferCapacity);
+    ZSTD_CCtx* const cctx = ZSTDMT_getCCtx(zcs->cctxPool);
+    unsigned const jobID = zcs->nextJobID & zcs->jobIDMask;
+
+    if ((cctx==NULL) || (dstBuffer.start==NULL)) {
+        zcs->jobs[jobID].jobCompleted = 1;
+        zcs->nextJobID++;
+        ZSTDMT_waitForAllJobsCompleted(zcs);
+        ZSTDMT_releaseAllJobResources(zcs);
+        return ERROR(memory_allocation);
+    }
+
+    DEBUGLOG(4, "preparing job %u to compress %u bytes with %u preload ", zcs->nextJobID, (U32)srcSize, (U32)zcs->dictSize);
+    zcs->jobs[jobID].src = zcs->inBuff.buffer;
+    zcs->jobs[jobID].srcStart = zcs->inBuff.buffer.start;
+    zcs->jobs[jobID].srcSize = srcSize;
+    zcs->jobs[jobID].dictSize = zcs->dictSize;   /* note : zcs->inBuff.filled is presumed >= srcSize + dictSize */
+    zcs->jobs[jobID].params = zcs->params;
+    if (zcs->nextJobID) zcs->jobs[jobID].params.fParams.checksumFlag = 0;  /* do not calculate checksum within sections, just keep it in header for first section */
+    zcs->jobs[jobID].cdict = zcs->nextJobID==0 ? zcs->cdict : NULL;
+    zcs->jobs[jobID].fullFrameSize = zcs->frameContentSize;
+    zcs->jobs[jobID].dstBuff = dstBuffer;
+    zcs->jobs[jobID].cctx = cctx;
+    zcs->jobs[jobID].firstChunk = (zcs->nextJobID==0);
+    zcs->jobs[jobID].lastChunk = endFrame;
+    zcs->jobs[jobID].jobCompleted = 0;
+    zcs->jobs[jobID].dstFlushed = 0;
+    zcs->jobs[jobID].jobCompleted_mutex = &zcs->jobCompleted_mutex;
+    zcs->jobs[jobID].jobCompleted_cond = &zcs->jobCompleted_cond;
+
+    /* get a new buffer for next input */
+    if (!endFrame) {
+        size_t const newDictSize = MIN(srcSize + zcs->dictSize, zcs->targetDictSize);
+        zcs->inBuff.buffer = ZSTDMT_getBuffer(zcs->buffPool, zcs->inBuffSize);
+        if (zcs->inBuff.buffer.start == NULL) {   /* not enough memory to allocate next input buffer */
+            zcs->jobs[jobID].jobCompleted = 1;
+            zcs->nextJobID++;
+            ZSTDMT_waitForAllJobsCompleted(zcs);
+            ZSTDMT_releaseAllJobResources(zcs);
+            return ERROR(memory_allocation);
+        }
+        DEBUGLOG(5, "inBuff filled to %u", (U32)zcs->inBuff.filled);
+        zcs->inBuff.filled -= srcSize + zcs->dictSize - newDictSize;
+        DEBUGLOG(5, "new job : filled to %u, with %u dict and %u src", (U32)zcs->inBuff.filled, (U32)newDictSize, (U32)(zcs->inBuff.filled - newDictSize));
+        memmove(zcs->inBuff.buffer.start, (const char*)zcs->jobs[jobID].srcStart + zcs->dictSize + srcSize - newDictSize, zcs->inBuff.filled);
+        DEBUGLOG(5, "new inBuff pre-filled");
+        zcs->dictSize = newDictSize;
+    } else {
+        zcs->inBuff.buffer = g_nullBuffer;
+        zcs->inBuff.filled = 0;
+        zcs->dictSize = 0;
+        zcs->frameEnded = 1;
+        if (zcs->nextJobID == 0)
+            zcs->params.fParams.checksumFlag = 0;   /* single chunk : checksum is calculated directly within worker thread */
+    }
+
+    DEBUGLOG(3, "posting job %u : %u bytes  (end:%u) (note : doneJob = %u=>%u)", zcs->nextJobID, (U32)zcs->jobs[jobID].srcSize, zcs->jobs[jobID].lastChunk, zcs->doneJobID, zcs->doneJobID & zcs->jobIDMask);
+    POOL_add(zcs->factory, ZSTDMT_compressChunk, &zcs->jobs[jobID]);   /* this call is blocking when thread worker pool is exhausted */
+    zcs->nextJobID++;
+    return 0;
+}
+
+
+/* ZSTDMT_flushNextJob() :
+ * output : will be updated with amount of data flushed .
+ * blockToFlush : if >0, the function will block and wait if there is no data available to flush .
+ * @return : amount of data remaining within internal buffer, 1 if unknown but > 0, 0 if no more, or an error code */
+static size_t ZSTDMT_flushNextJob(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output, unsigned blockToFlush)
+{
+    unsigned const wJobID = zcs->doneJobID & zcs->jobIDMask;
+    if (zcs->doneJobID == zcs->nextJobID) return 0;   /* all flushed ! */
+    PTHREAD_MUTEX_LOCK(&zcs->jobCompleted_mutex);
+    while (zcs->jobs[wJobID].jobCompleted==0) {
+        DEBUGLOG(5, "waiting for jobCompleted signal from job %u", zcs->doneJobID);
+        if (!blockToFlush) { pthread_mutex_unlock(&zcs->jobCompleted_mutex); return 0; }  /* nothing ready to be flushed => skip */
+        pthread_cond_wait(&zcs->jobCompleted_cond, &zcs->jobCompleted_mutex);  /* block when nothing available to flush */
+    }
+    pthread_mutex_unlock(&zcs->jobCompleted_mutex);
+    /* compression job completed : output can be flushed */
+    {   ZSTDMT_jobDescription job = zcs->jobs[wJobID];
+        if (!job.jobScanned) {
+            if (ZSTD_isError(job.cSize)) {
+                DEBUGLOG(5, "compression error detected ");
+                ZSTDMT_waitForAllJobsCompleted(zcs);
+                ZSTDMT_releaseAllJobResources(zcs);
+                return job.cSize;
+            }
+            ZSTDMT_releaseCCtx(zcs->cctxPool, job.cctx);
+            zcs->jobs[wJobID].cctx = NULL;
+            DEBUGLOG(5, "zcs->params.fParams.checksumFlag : %u ", zcs->params.fParams.checksumFlag);
+            if (zcs->params.fParams.checksumFlag) {
+                XXH64_update(&zcs->xxhState, (const char*)job.srcStart + job.dictSize, job.srcSize);
+                if (zcs->frameEnded && (zcs->doneJobID+1 == zcs->nextJobID)) {  /* write checksum at end of last section */
+                    U32 const checksum = (U32)XXH64_digest(&zcs->xxhState);
+                    DEBUGLOG(4, "writing checksum : %08X \n", checksum);
+                    MEM_writeLE32((char*)job.dstBuff.start + job.cSize, checksum);
+                    job.cSize += 4;
+                    zcs->jobs[wJobID].cSize += 4;
+            }   }
+            ZSTDMT_releaseBuffer(zcs->buffPool, job.src);
+            zcs->jobs[wJobID].srcStart = NULL;
+            zcs->jobs[wJobID].src = g_nullBuffer;
+            zcs->jobs[wJobID].jobScanned = 1;
+        }
+        {   size_t const toWrite = MIN(job.cSize - job.dstFlushed, output->size - output->pos);
+            DEBUGLOG(4, "Flushing %u bytes from job %u ", (U32)toWrite, zcs->doneJobID);
+            memcpy((char*)output->dst + output->pos, (const char*)job.dstBuff.start + job.dstFlushed, toWrite);
+            output->pos += toWrite;
+            job.dstFlushed += toWrite;
+        }
+        if (job.dstFlushed == job.cSize) {   /* output buffer fully flushed => move to next one */
+            ZSTDMT_releaseBuffer(zcs->buffPool, job.dstBuff);
+            zcs->jobs[wJobID].dstBuff = g_nullBuffer;
+            zcs->jobs[wJobID].jobCompleted = 0;
+            zcs->doneJobID++;
+        } else {
+            zcs->jobs[wJobID].dstFlushed = job.dstFlushed;
+        }
+        /* return value : how many bytes left in buffer ; fake it to 1 if unknown but >0 */
+        if (job.cSize > job.dstFlushed) return (job.cSize - job.dstFlushed);
+        if (zcs->doneJobID < zcs->nextJobID) return 1;   /* still some buffer to flush */
+        zcs->allJobsCompleted = zcs->frameEnded;   /* frame completed and entirely flushed */
+        return 0;   /* everything flushed */
+}   }
+
+
+size_t ZSTDMT_compressStream(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
+{
+    if (zcs->frameEnded) return ERROR(stage_wrong);   /* current frame being ended. Only flush is allowed. Restart with init */
+    if (zcs->nbThreads==1) return ZSTD_compressStream(zcs->cstream, output, input);
+
+    /* fill input buffer */
+    {   size_t const toLoad = MIN(input->size - input->pos, zcs->inBuffSize - zcs->inBuff.filled);
+        memcpy((char*)zcs->inBuff.buffer.start + zcs->inBuff.filled, input->src, toLoad);
+        input->pos += toLoad;
+        zcs->inBuff.filled += toLoad;
+    }
+
+    if ( (zcs->inBuff.filled == zcs->inBuffSize)  /* filled enough : let's compress */
+        && (zcs->nextJobID <= zcs->doneJobID + zcs->jobIDMask) ) {   /* avoid overwriting job round buffer */
+        CHECK_F( ZSTDMT_createCompressionJob(zcs, zcs->targetSectionSize, 0) );
+    }
+
+    /* check for data to flush */
+    CHECK_F( ZSTDMT_flushNextJob(zcs, output, (zcs->inBuff.filled == zcs->inBuffSize)) ); /* block if it wasn't possible to create new job due to saturation */
+
+    /* recommended next input size : fill current input buffer */
+    return zcs->inBuffSize - zcs->inBuff.filled;   /* note : could be zero when input buffer is fully filled and no more availability to create new job */
+}
+
+
+static size_t ZSTDMT_flushStream_internal(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output, unsigned endFrame)
+{
+    size_t const srcSize = zcs->inBuff.filled - zcs->dictSize;
+
+    if (srcSize) DEBUGLOG(4, "flushing : %u bytes left to compress", (U32)srcSize);
+    if ( ((srcSize > 0) || (endFrame && !zcs->frameEnded))
+       && (zcs->nextJobID <= zcs->doneJobID + zcs->jobIDMask) ) {
+        CHECK_F( ZSTDMT_createCompressionJob(zcs, srcSize, endFrame) );
+    }
+
+    /* check if there is any data available to flush */
+    DEBUGLOG(5, "zcs->doneJobID : %u  ; zcs->nextJobID : %u ", zcs->doneJobID, zcs->nextJobID);
+    return ZSTDMT_flushNextJob(zcs, output, 1);
+}
+
+
+size_t ZSTDMT_flushStream(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output)
+{
+    if (zcs->nbThreads==1) return ZSTD_flushStream(zcs->cstream, output);
+    return ZSTDMT_flushStream_internal(zcs, output, 0);
+}
+
+size_t ZSTDMT_endStream(ZSTDMT_CCtx* zcs, ZSTD_outBuffer* output)
+{
+    if (zcs->nbThreads==1) return ZSTD_endStream(zcs->cstream, output);
+    return ZSTDMT_flushStream_internal(zcs, output, 1);
+}
--- a/lib/compress/zstdmt_compress.h
+++ b/lib/compress/zstdmt_compress.h
@ -0,0 +1,64 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+
+/* Note : All prototypes defined in this file shall be considered experimental.
+ *        There is no guarantee of API continuity (yet) on any of these prototypes */
+
+/* ===   Dependencies   === */
+#include <stddef.h>   /* size_t */
+#define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_parameters */
+#include "zstd.h"     /* ZSTD_inBuffer, ZSTD_outBuffer, ZSTDLIB_API */
+
+
+/* ===   Simple one-pass functions   === */
+
+typedef struct ZSTDMT_CCtx_s ZSTDMT_CCtx;
+ZSTDLIB_API ZSTDMT_CCtx* ZSTDMT_createCCtx(unsigned nbThreads);
+ZSTDLIB_API size_t ZSTDMT_freeCCtx(ZSTDMT_CCtx* cctx);
+
+ZSTDLIB_API size_t ZSTDMT_compressCCtx(ZSTDMT_CCtx* cctx,
+                           void* dst, size_t dstCapacity,
+                     const void* src, size_t srcSize,
+                           int compressionLevel);
+
+
+/* ===   Streaming functions   === */
+
+ZSTDLIB_API size_t ZSTDMT_initCStream(ZSTDMT_CCtx* mtctx, int compressionLevel);
+ZSTDLIB_API size_t ZSTDMT_resetCStream(ZSTDMT_CCtx* mtctx, unsigned long long pledgedSrcSize);    /**< pledgedSrcSize is optional and can be zero == unknown */
+
+ZSTDLIB_API size_t ZSTDMT_compressStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
+
+ZSTDLIB_API size_t ZSTDMT_flushStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output);   /**< @return : 0 == all flushed; >0 : still some data to be flushed; or an error code (ZSTD_isError()) */
+ZSTDLIB_API size_t ZSTDMT_endStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output);     /**< @return : 0 == all flushed; >0 : still some data to be flushed; or an error code (ZSTD_isError()) */
+
+
+/* ===   Advanced functions and parameters  === */
+
+#ifndef ZSTDMT_SECTION_SIZE_MIN
+#  define ZSTDMT_SECTION_SIZE_MIN (1U << 20)   /* 1 MB - Minimum size of each compression job */
+#endif
+
+ZSTDLIB_API size_t ZSTDMT_initCStream_advanced(ZSTDMT_CCtx* mtctx, const void* dict, size_t dictSize,  /**< dict can be released after init, a local copy is preserved within zcs */
+                                          ZSTD_parameters params, unsigned long long pledgedSrcSize);  /**< pledgedSrcSize is optional and can be zero == unknown */
+
+/* ZSDTMT_parameter :
+ * List of parameters that can be set using ZSTDMT_setMTCtxParameter() */
+typedef enum {
+    ZSTDMT_p_sectionSize,        /* size of input "section". Each section is compressed in parallel. 0 means default, which is dynamically determined within compression functions */
+    ZSTDMT_p_overlapSectionRLog  /* reverse log of overlapped section; 0 == use a complete window, 3(default) == use 1/8th of window, values >=10 means no overlap */
+} ZSDTMT_parameter;
+
+/* ZSTDMT_setMTCtxParameter() :
+ * allow setting individual parameters, one at a time, among a list of enums defined in ZSTDMT_parameter.
+ * The function must be called typically after ZSTD_createCCtx().
+ * Parameters not explicitly reset by ZSTDMT_init*() remain the same in consecutive compression sessions.
+ * @return : 0, or an error code (which can be tested using ZSTD_isError()) */
+ZSTDLIB_API size_t ZSTDMT_setMTCtxParameter(ZSTDMT_CCtx* mtctx, ZSDTMT_parameter parameter, unsigned value);
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@ -1936,7 +1936,7 @@ size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t di
    zds->stage = zdss_loadHeader;
    zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
    ZSTD_freeDDict(zds->ddictLocal);
-    if (dict) {
+    if (dict && dictSize >= 8) {
        zds->ddictLocal = ZSTD_createDDict(dict, dictSize);
        if (zds->ddictLocal == NULL) return ERROR(memory_allocation);
    } else zds->ddictLocal = NULL;
@ -1973,7 +1973,7 @@ size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds,
    switch(paramType)
    {
        default : return ERROR(parameter_unknown);
-        case ZSTDdsp_maxWindowSize : zds->maxWindowSize = paramValue ? paramValue : (U32)(-1); break;
+        case DStream_p_maxWindowSize : zds->maxWindowSize = paramValue ? paramValue : (U32)(-1); break;
    }
    return 0;
 }
--- a/lib/zstd.h
+++ b/lib/zstd.h
@ -369,9 +369,9 @@ typedef struct {
 } ZSTD_compressionParameters;

 typedef struct {
-    unsigned contentSizeFlag; /**< 1: content size will be in frame header (if known). */
-    unsigned checksumFlag;    /**< 1: will generate a 32-bits checksum at end of frame, to be used for error detection by decompressor */
-    unsigned noDictIDFlag;    /**< 1: no dict ID will be saved into frame header (if dictionary compression) */
+    unsigned contentSizeFlag; /**< 1: content size will be in frame header (when known) */
+    unsigned checksumFlag;    /**< 1: generate a 32-bits checksum at end of frame, for error detection */
+    unsigned noDictIDFlag;    /**< 1: no dictID will be saved into frame header (if dictionary compression) */
 } ZSTD_frameParameters;

 typedef struct {
@ -401,6 +401,14 @@ ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
 *  Gives the amount of memory used by a given ZSTD_CCtx */
 ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);

+typedef enum {
+    ZSTD_p_forceWindow   /* Force back-references to remain < windowSize, even when referencing Dictionary content (default:0)*/
+} ZSTD_CCtxParameter;
+/*! ZSTD_setCCtxParameter() :
+ *  Set advanced parameters, selected through enum ZSTD_CCtxParameter
+ *  @result : 0, or an error code (which can be tested with ZSTD_isError()) */
+ZSTDLIB_API size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter param, unsigned value);
+
 /*! ZSTD_createCDict_byReference() :
 *  Create a digested dictionary for compression
 *  Dictionary content is simply referenced, and therefore stays in dictBuffer.
@ -510,7 +518,7 @@ ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
 /*=====   Advanced Streaming compression functions  =====*/
 ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
 ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize);   /**< pledgedSrcSize must be correct */
-ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel);
+ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); /**< note: a dict will not be used if dict == NULL or dictSize < 8 */
 ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
                                             ZSTD_parameters params, unsigned long long pledgedSrcSize);  /**< pledgedSrcSize is optional and can be zero == unknown */
 ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);  /**< note : cdict will just be referenced, and must outlive compression session */
@ -519,9 +527,9 @@ ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);


 /*=====   Advanced Streaming decompression functions  =====*/
-typedef enum { ZSTDdsp_maxWindowSize } ZSTD_DStreamParameter_e;
+typedef enum { DStream_p_maxWindowSize } ZSTD_DStreamParameter_e;
 ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem);
-ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize);
+ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); /**< note: a dict will not be used if dict == NULL or dictSize < 8 */
 ZSTDLIB_API size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue);
 ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict);  /**< note : ddict will just be referenced, and must outlive decompression session */
 ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds);  /**< re-use decompression parameters from previous init; saves dictionary loading */
@ -561,10 +569,10 @@ ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
    In which case, it will "discard" the relevant memory section from its history.

  Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum.
-  It's possible to use a NULL,0 src content, in which case, it will write a final empty block to end the frame,
-  Without last block mark, frames will be considered unfinished (broken) by decoders.
+  It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame.
+  Without last block mark, frames will be considered unfinished (corrupted) by decoders.

-  You can then reuse `ZSTD_CCtx` (ZSTD_compressBegin()) to compress some new frame.
+  `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress some new frame.
 */

 /*=====   Buffer-less streaming compression functions  =====*/
@ -572,6 +580,7 @@ ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
 ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
 ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize);
 ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize);
+ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict, unsigned long long pledgedSrcSize);
 ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
 ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);

--- a/programs/Makefile
+++ b/programs/Makefile
@ -1,5 +1,5 @@
 # ##########################################################################
-# Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+# Copyright (c) 2015-present, Yann Collet, Facebook, Inc.
 # All rights reserved.
 #
 # This Makefile is validated for Linux, macOS, *BSD, Hurd, Solaris, MSYS2 targets
@ -24,7 +24,7 @@ else
 ALIGN_LOOP =
 endif

-CPPFLAGS+= -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/dictBuilder
+CPPFLAGS+= -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/compress -I$(ZSTDDIR)/dictBuilder
 CFLAGS  ?= -O3
 CFLAGS  += -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow -Wstrict-aliasing=1 \
          -Wswitch-enum -Wdeclaration-after-statement -Wstrict-prototypes -Wundef \
@ -34,8 +34,8 @@ FLAGS    = $(CPPFLAGS) $(CFLAGS) $(LDFLAGS)


 ZSTDCOMMON_FILES := $(ZSTDDIR)/common/*.c
-ZSTDCOMP_FILES := $(ZSTDDIR)/compress/zstd_compress.c $(ZSTDDIR)/compress/fse_compress.c $(ZSTDDIR)/compress/huf_compress.c
-ZSTDDECOMP_FILES := $(ZSTDDIR)/decompress/huf_decompress.c
+ZSTDCOMP_FILES := $(ZSTDDIR)/compress/*.c
+ZSTDDECOMP_FILES := $(ZSTDDIR)/decompress/*.c
 ZSTD_FILES := $(ZSTDDECOMP_FILES) $(ZSTDCOMMON_FILES) $(ZSTDCOMP_FILES)
 ZDICT_FILES := $(ZSTDDIR)/dictBuilder/*.c
 ZSTDDECOMP_O = $(ZSTDDIR)/decompress/zstd_decompress.o
@ -49,6 +49,8 @@ CPPFLAGS  += -I$(ZSTDDIR)/legacy
 ZSTDLEGACY_FILES:= $(ZSTDDIR)/legacy/*.c
 endif

+ZSTDLIB_FILES := $(wildcard $(ZSTD_FILES)) $(wildcard $(ZSTDLEGACY_FILES)) $(wildcard $(ZDICT_FILES))
+ZSTDLIB_OBJ   := $(patsubst %.c,%.o,$(ZSTDLIB_FILES))

 # Define *.exe as extension for Windows systems
 ifneq (,$(filter Windows%,$(OS)))
@ -74,8 +76,7 @@ all: zstd
 $(ZSTDDECOMP_O): CFLAGS += $(ALIGN_LOOP)

 zstd  : CPPFLAGS += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
-zstd  : $(ZSTDDECOMP_O) $(ZSTD_FILES) $(ZSTDLEGACY_FILES) $(ZDICT_FILES) \
-        zstdcli.c fileio.c bench.c datagen.c dibio.c
+zstd  : $(ZSTDLIB_OBJ) zstdcli.o fileio.o bench.o datagen.o dibio.o
 ifneq (,$(filter Windows%,$(OS)))
 	windres/generate_res.bat
 endif
@ -83,8 +84,7 @@ endif


 zstd32 : CPPFLAGS += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
-zstd32 : $(ZSTDDIR)/decompress/zstd_decompress.c $(ZSTD_FILES) $(ZSTDLEGACY_FILES) $(ZDICT_FILES) \
-        zstdcli.c fileio.c bench.c datagen.c dibio.c
+zstd32 : $(ZSTDLIB_FILES) zstdcli.c fileio.c bench.c datagen.c dibio.c
 ifneq (,$(filter Windows%,$(OS)))
 	windres/generate_res.bat
 endif
@ -106,32 +106,33 @@ zstd-pgo : clean zstd
 	$(RM) $(ZSTDDECOMP_O)
 	$(MAKE) zstd MOREFLAGS=-fprofile-use

-zstd-frugal: $(ZSTDDECOMP_O) $(ZSTD_FILES) zstdcli.c fileio.c
+zstd-frugal: $(ZSTD_FILES) zstdcli.c fileio.c
 	$(CC) $(FLAGS) -DZSTD_NOBENCH -DZSTD_NODICT $^ -o zstd$(EXT)

-zstd-small: clean_decomp_o
-	ZSTD_LEGACY_SUPPORT=0 CFLAGS="-Os -s" $(MAKE) zstd-frugal
+zstd-small:
+	CFLAGS="-Os -s" $(MAKE) zstd-frugal

-zstd-decompress-clean: $(ZSTDDECOMP_O) $(ZSTDCOMMON_FILES) $(ZSTDDECOMP_FILES) zstdcli.c fileio.c
-	$(CC) $(FLAGS) -DZSTD_NOBENCH -DZSTD_NODICT -DZSTD_NOCOMPRESS $^ -o zstd-decompress$(EXT)
-
-zstd-decompress: clean_decomp_o
-	ZSTD_LEGACY_SUPPORT=0 $(MAKE) zstd-decompress-clean
+zstd-decompress: $(ZSTDCOMMON_FILES) $(ZSTDDECOMP_FILES) zstdcli.c fileio.c
+	$(CC) $(FLAGS) -DZSTD_NOBENCH -DZSTD_NODICT -DZSTD_NOCOMPRESS $^ -o $@$(EXT)

 zstd-compress: $(ZSTDCOMMON_FILES) $(ZSTDCOMP_FILES) zstdcli.c fileio.c
 	$(CC) $(FLAGS) -DZSTD_NOBENCH -DZSTD_NODICT -DZSTD_NODECOMPRESS $^ -o $@$(EXT)

-gzstd: clean_decomp_o
+gzstd:
 	@echo "int main(){}" | $(CC) -o have_zlib -x c - -lz && echo found zlib || echo did not found zlib
 	@if [ -s have_zlib ]; then \
        echo building gzstd with .gz decompression support \
-        && rm have_zlib$(EXT) \
+        && $(RM) have_zlib$(EXT) fileio.o \
        && CPPFLAGS=-DZSTD_GZDECOMPRESS LDFLAGS="-lz" $(MAKE) zstd; \
    else \
        echo "WARNING : no zlib, building gzstd with only .zst files support : NO .gz SUPPORT !!!" \
        && $(MAKE) zstd; \
    fi

+zstdmt: CPPFLAGS += -DZSTD_MULTITHREAD
+zstdmt: LDFLAGS += -lpthread
+zstdmt: zstd
+
 generate_res:
 	windres/generate_res.bat

@ -166,7 +167,7 @@ ifneq (,$(filter $(shell uname),OpenBSD FreeBSD NetBSD DragonFly SunOS))
 MANDIR  ?= $(PREFIX)/man/man1
 else
 MANDIR  ?= $(PREFIX)/share/man/man1
-endif 
+endif

 INSTALL_PROGRAM ?= $(INSTALL) -m 755
 INSTALL_SCRIPT  ?= $(INSTALL) -m 755
--- a/programs/bench.c
+++ b/programs/bench.c
@ -9,6 +9,14 @@



+/* **************************************
+*  Tuning parameters
+****************************************/
+#ifndef BMK_TIMETEST_DEFAULT_S   /* default minimum time per test */
+#define BMK_TIMETEST_DEFAULT_S 3
+#endif
+
+
 /* **************************************
 *  Compiler Warnings
 ****************************************/
@ -24,7 +32,7 @@
 #include "util.h"        /* UTIL_getFileSize, UTIL_sleep */
 #include <stdlib.h>      /* malloc, free */
 #include <string.h>      /* memset */
-#include <stdio.h>       /* fprintf, fopen, ftello64 */
+#include <stdio.h>       /* fprintf, fopen */
 #include <time.h>        /* clock_t, clock, CLOCKS_PER_SEC */

 #include "mem.h"
@ -43,7 +51,6 @@
 #  define ZSTD_GIT_COMMIT_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_GIT_COMMIT)
 #endif

-#define NBSECONDS             3
 #define TIMELOOP_MICROSEC     1*1000000ULL /* 1 second */
 #define ACTIVEPERIOD_MICROSEC 70*1000000ULL /* 70 seconds */
 #define COOLPERIOD_SEC        10
@ -92,8 +99,6 @@ static clock_t g_time = 0;
 /* *************************************
 *  Benchmark Parameters
 ***************************************/
-static U32 g_nbSeconds = NBSECONDS;
-static size_t g_blockSize = 0;
 static int g_additionalParam = 0;
 static U32 g_decodeOnly = 0;

@ -101,19 +106,30 @@ void BMK_setNotificationLevel(unsigned level) { g_displayLevel=level; }

 void BMK_setAdditionalParam(int additionalParam) { g_additionalParam=additionalParam; }

-void BMK_SetNbSeconds(unsigned nbSeconds)
+static U32 g_nbSeconds = BMK_TIMETEST_DEFAULT_S;
+void BMK_setNbSeconds(unsigned nbSeconds)
 {
    g_nbSeconds = nbSeconds;
-    DISPLAYLEVEL(3, "- test >= %u seconds per compression / decompression -\n", g_nbSeconds);
+    DISPLAYLEVEL(3, "- test >= %u seconds per compression / decompression - \n", g_nbSeconds);
 }

-void BMK_SetBlockSize(size_t blockSize)
+static size_t g_blockSize = 0;
+void BMK_setBlockSize(size_t blockSize)
 {
    g_blockSize = blockSize;
-    DISPLAYLEVEL(2, "using blocks of size %u KB \n", (U32)(blockSize>>10));
+    if (g_blockSize) DISPLAYLEVEL(2, "using blocks of size %u KB \n", (U32)(blockSize>>10));
+}
+
+void BMK_setDecodeOnlyMode(unsigned decodeFlag) { g_decodeOnly = (decodeFlag>0); }
+
+static U32 g_nbThreads = 1;
+void BMK_setNbThreads(unsigned nbThreads) {
+#ifndef ZSTD_MULTITHREAD
+    if (nbThreads > 1) DISPLAYLEVEL(2, "Note : multi-threading is disabled \n");
+#endif
+    g_nbThreads = nbThreads;
 }

-void BMK_setDecodeOnly(unsigned decodeFlag) { g_decodeOnly = (decodeFlag>0); }

 /* ********************************************************
 *  Bench functions
@ -132,6 +148,8 @@ typedef struct {
 #define MIN(a,b) ((a)<(b) ? (a) : (b))
 #define MAX(a,b) ((a)>(b) ? (a) : (b))

+#include "compress/zstdmt_compress.h"
+
 static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                        const char* displayName, int cLevel,
                        const size_t* fileSizes, U32 nbFiles,
@ -145,6 +163,7 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
    size_t const maxCompressedSize = ZSTD_compressBound(srcSize) + (maxNbBlocks * 1024);   /* add some room for safety */
    void* const compressedBuffer = malloc(maxCompressedSize);
    void* resultBuffer = malloc(srcSize);
+    ZSTDMT_CCtx* const mtctx = ZSTDMT_createCCtx(g_nbThreads);
    ZSTD_CCtx* const ctx = ZSTD_createCCtx();
    ZSTD_DCtx* const dctx = ZSTD_createDCtx();
    size_t const loadedCompressedSize = srcSize;
@ -212,7 +231,7 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
    /* Bench */
    {   U64 fastestC = (U64)(-1LL), fastestD = (U64)(-1LL);
        U64 const crcOrig = g_decodeOnly ? 0 : XXH64(srcBuffer, srcSize, 0);
-        UTIL_time_t coolTime;
+        UTIL_time_t coolTime, coolTick;
        U64 const maxTime = (g_nbSeconds * TIMELOOP_MICROSEC) + 1;
        U64 totalCTime=0, totalDTime=0;
        U32 cCompleted=g_decodeOnly, dCompleted=0;
@ -220,25 +239,27 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
        const char* const marks[NB_MARKS] = { " |", " /", " =",  "\\" };
        U32 markNb = 0;

+        UTIL_initTimer(&coolTick);
        UTIL_getTime(&coolTime);
        DISPLAYLEVEL(2, "\r%79s\r", "");
        while (!cCompleted || !dCompleted) {
-            UTIL_time_t clockStart;

            /* overheat protection */
-            if (UTIL_clockSpanMicro(coolTime, ticksPerSecond) > ACTIVEPERIOD_MICROSEC) {
+            if (UTIL_clockSpanMicro(coolTime, coolTick) > ACTIVEPERIOD_MICROSEC) {
                DISPLAYLEVEL(2, "\rcooling down ...    \r");
                UTIL_sleep(COOLPERIOD_SEC);
                UTIL_getTime(&coolTime);
            }

            if (!g_decodeOnly) {
+                UTIL_time_t clockTick, clockStart;
                /* Compression */
                DISPLAYLEVEL(2, "%2s-%-17.17s :%10u ->\r", marks[markNb], displayName, (U32)srcSize);
                if (!cCompleted) memset(compressedBuffer, 0xE5, maxCompressedSize);  /* warm up and erase result buffer */

                UTIL_sleepMilli(1);  /* give processor time to other processes */
                UTIL_waitForNextTick(ticksPerSecond);
+                UTIL_initTimer(&clockTick);
                UTIL_getTime(&clockStart);

                if (!cCompleted) {   /* still some time to do compression tests */
@ -265,19 +286,26 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                                                blockTable[blockNb].srcPtr,blockTable[blockNb].srcSize,
                                                cdict);
                            } else {
+#ifdef ZSTD_MULTITHREAD         /* note : limitation : MT single-pass does not support compression with dictionary */
+                                rSize = ZSTDMT_compressCCtx(mtctx,
+                                                blockTable[blockNb].cPtr,  blockTable[blockNb].cRoom,
+                                                blockTable[blockNb].srcPtr,blockTable[blockNb].srcSize,
+                                                cLevel);
+#else
                                rSize = ZSTD_compress_advanced (ctx,
                                                blockTable[blockNb].cPtr,  blockTable[blockNb].cRoom,
                                                blockTable[blockNb].srcPtr,blockTable[blockNb].srcSize, NULL, 0, zparams);
+#endif
                            }
                            if (ZSTD_isError(rSize)) EXM_THROW(1, "ZSTD_compress_usingCDict() failed : %s", ZSTD_getErrorName(rSize));
                            blockTable[blockNb].cSize = rSize;
                        }
                        nbLoops++;
-                    } while (UTIL_clockSpanMicro(clockStart, ticksPerSecond) < clockLoop);
+                    } while (UTIL_clockSpanMicro(clockStart, clockTick) < clockLoop);
                    ZSTD_freeCDict(cdict);
-                    {   U64 const clockSpan = UTIL_clockSpanMicro(clockStart, ticksPerSecond);
-                        if (clockSpan < fastestC*nbLoops) fastestC = clockSpan / nbLoops;
-                        totalCTime += clockSpan;
+                    {   U64 const clockSpanMicro = UTIL_clockSpanMicro(clockStart, clockTick);
+                        if (clockSpanMicro < fastestC*nbLoops) fastestC = clockSpanMicro / nbLoops;
+                        totalCTime += clockSpanMicro;
                        cCompleted = (totalCTime >= maxTime);
                }   }

@ -292,20 +320,24 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                memcpy(compressedBuffer, srcBuffer, loadedCompressedSize);
            }

-            (void)fastestD; (void)crcOrig;   /*  unused when decompression disabled */
-#if 1
+#if 0       /* disable decompression test */
+            dCompleted=1;
+            (void)totalDTime; (void)fastestD; (void)crcOrig;   /*  unused when decompression disabled */
+#else
            /* Decompression */
            if (!dCompleted) memset(resultBuffer, 0xD6, srcSize);  /* warm result buffer */

            UTIL_sleepMilli(1); /* give processor time to other processes */
            UTIL_waitForNextTick(ticksPerSecond);
-            UTIL_getTime(&clockStart);

            if (!dCompleted) {
                U64 clockLoop = g_nbSeconds ? TIMELOOP_MICROSEC : 1;
                U32 nbLoops = 0;
+                UTIL_time_t clockStart, clockTick;
                ZSTD_DDict* const ddict = ZSTD_createDDict(dictBuffer, dictBufferSize);
                if (!ddict) EXM_THROW(2, "ZSTD_createDDict() allocation failure");
+                UTIL_initTimer(&clockTick);
+                UTIL_getTime(&clockStart);
                do {
                    U32 blockNb;
                    for (blockNb=0; blockNb<nbBlocks; blockNb++) {
@ -314,19 +346,19 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                            blockTable[blockNb].cPtr, blockTable[blockNb].cSize,
                            ddict);
                        if (ZSTD_isError(regenSize)) {
-                            DISPLAY("ZSTD_decompress_usingDDict() failed on block %u : %s  \n",
-                                      blockNb, ZSTD_getErrorName(regenSize));
+                            DISPLAY("ZSTD_decompress_usingDDict() failed on block %u of size %u : %s  \n",
+                                      blockNb, (U32)blockTable[blockNb].cSize, ZSTD_getErrorName(regenSize));
                            clockLoop = 0;   /* force immediate test end */
                            break;
                        }
                        blockTable[blockNb].resSize = regenSize;
                    }
                    nbLoops++;
-                } while (UTIL_clockSpanMicro(clockStart, ticksPerSecond) < clockLoop);
+                } while (UTIL_clockSpanMicro(clockStart, clockTick) < clockLoop);
                ZSTD_freeDDict(ddict);
-                {   U64 const clockSpan = UTIL_clockSpanMicro(clockStart, ticksPerSecond);
-                    if (clockSpan < fastestD*nbLoops) fastestD = clockSpan / nbLoops;
-                    totalDTime += clockSpan;
+                {   U64 const clockSpanMicro = UTIL_clockSpanMicro(clockStart, clockTick);
+                    if (clockSpanMicro < fastestD*nbLoops) fastestD = clockSpanMicro / nbLoops;
+                    totalDTime += clockSpanMicro;
                    dCompleted = (totalDTime >= maxTime);
            }   }

@ -353,6 +385,17 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
                            pos = (U32)(u - bacc);
                            bNb = pos / (128 KB);
                            DISPLAY("(block %u, sub %u, pos %u) \n", segNb, bNb, pos);
+                            if (u>5) {
+                                int n;
+                                for (n=-5; n<0; n++) DISPLAY("%02X ", ((const BYTE*)srcBuffer)[u+n]);
+                                DISPLAY(" :%02X:  ", ((const BYTE*)srcBuffer)[u]);
+                                for (n=1; n<3; n++) DISPLAY("%02X ", ((const BYTE*)srcBuffer)[u+n]);
+                                DISPLAY(" \n");
+                                for (n=-5; n<0; n++) DISPLAY("%02X ", ((const BYTE*)resultBuffer)[u+n]);
+                                DISPLAY(" :%02X:  ", ((const BYTE*)resultBuffer)[u]);
+                                for (n=1; n<3; n++) DISPLAY("%02X ", ((const BYTE*)resultBuffer)[u+n]);
+                                DISPLAY(" \n");
+                            }
                            break;
                        }
                        if (u==srcSize-1) {  /* should never happen */
@ -378,6 +421,7 @@ static int BMK_benchMem(const void* srcBuffer, size_t srcSize,
    free(blockTable);
    free(compressedBuffer);
    free(resultBuffer);
+    ZSTDMT_freeCCtx(mtctx);
    ZSTD_freeCCtx(ctx);
    ZSTD_freeDCtx(dctx);
    return 0;
--- a/programs/bench.h
+++ b/programs/bench.h
@ -15,14 +15,15 @@
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
 #include "zstd.h"     /* ZSTD_compressionParameters */

-int BMK_benchFiles(const char** fileNamesTable, unsigned nbFiles,const char* dictFileName, 
+int BMK_benchFiles(const char** fileNamesTable, unsigned nbFiles,const char* dictFileName,
                   int cLevel, int cLevelLast, ZSTD_compressionParameters* compressionParams);

 /* Set Parameters */
-void BMK_SetNbSeconds(unsigned nbLoops);
-void BMK_SetBlockSize(size_t blockSize);
-void BMK_setAdditionalParam(int additionalParam);
+void BMK_setNbSeconds(unsigned nbLoops);
+void BMK_setBlockSize(size_t blockSize);
+void BMK_setNbThreads(unsigned nbThreads);
 void BMK_setNotificationLevel(unsigned level);
-void BMK_setDecodeOnly(unsigned decodeFlag);
+void BMK_setAdditionalParam(int additionalParam);
+void BMK_setDecodeOnlyMode(unsigned decodeFlag);

 #endif   /* BENCH_H_121279284357 */
--- a/programs/fileio.c
+++ b/programs/fileio.c
@ -7,6 +7,7 @@
 * of patent rights can be found in the PATENTS file in the same directory.
 */

+
 /* *************************************
 *  Compiler Options
 ***************************************/
@ -34,11 +35,14 @@
 #include "fileio.h"
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_magicNumber, ZSTD_frameHeaderSize_max */
 #include "zstd.h"
-#ifdef ZSTD_GZDECOMPRESS
-#include "zlib.h"
-#if !defined(z_const)
-    #define z_const
+#ifdef ZSTD_MULTITHREAD
+#  include "zstdmt_compress.h"
 #endif
+#ifdef ZSTD_GZDECOMPRESS
+#  include "zlib.h"
+#  if !defined(z_const)
+#    define z_const
+#  endif
 #endif


@ -103,7 +107,23 @@ static U32 g_removeSrcFile = 0;
 void FIO_setRemoveSrcFile(unsigned flag) { g_removeSrcFile = (flag>0); }
 static U32 g_memLimit = 0;
 void FIO_setMemLimit(unsigned memLimit) { g_memLimit = memLimit; }
-
+static U32 g_nbThreads = 1;
+void FIO_setNbThreads(unsigned nbThreads) {
+#ifndef ZSTD_MULTITHREAD
+    if (nbThreads > 1) DISPLAYLEVEL(2, "Note : multi-threading is disabled \n");
+#endif
+    g_nbThreads = nbThreads;
+}
+static U32 g_blockSize = 0;
+void FIO_setBlockSize(unsigned blockSize) {
+    if (blockSize && g_nbThreads==1)
+        DISPLAYLEVEL(2, "Setting block size is useless in single-thread mode \n");
+#ifdef ZSTD_MULTITHREAD
+    if (blockSize-1 < ZSTDMT_SECTION_SIZE_MIN-1)   /* intentional underflow */
+        DISPLAYLEVEL(2, "Note : minimum block size is %u KB \n", (ZSTDMT_SECTION_SIZE_MIN>>10));
+#endif
+    g_blockSize = blockSize;
+}


 /*-*************************************
@ -230,23 +250,34 @@ static size_t FIO_loadFile(void** bufferPtr, const char* fileName)
 *  Compression
 ************************************************************************/
 typedef struct {
+    FILE* srcFile;
+    FILE* dstFile;
    void*  srcBuffer;
    size_t srcBufferSize;
    void*  dstBuffer;
    size_t dstBufferSize;
+#ifdef ZSTD_MULTITHREAD
+    ZSTDMT_CCtx* cctx;
+#else
    ZSTD_CStream* cctx;
-    FILE* dstFile;
-    FILE* srcFile;
+#endif
 } cRess_t;

-static cRess_t FIO_createCResources(const char* dictFileName, int cLevel, 
+static cRess_t FIO_createCResources(const char* dictFileName, int cLevel,
                                    U64 srcSize, ZSTD_compressionParameters* comprParams)
 {
    cRess_t ress;
    memset(&ress, 0, sizeof(ress));

+#ifdef ZSTD_MULTITHREAD
+    ress.cctx = ZSTDMT_createCCtx(g_nbThreads);
+    if (ress.cctx == NULL) EXM_THROW(30, "zstd: allocation error : can't create ZSTD_CStream");
+    if (cLevel==ZSTD_maxCLevel())
+        ZSTDMT_setMTCtxParameter(ress.cctx, ZSTDMT_p_overlapSectionRLog, 0);   /* use complete window for overlap */
+#else
    ress.cctx = ZSTD_createCStream();
    if (ress.cctx == NULL) EXM_THROW(30, "zstd: allocation error : can't create ZSTD_CStream");
+#endif
    ress.srcBufferSize = ZSTD_CStreamInSize();
    ress.srcBuffer = malloc(ress.srcBufferSize);
    ress.dstBufferSize = ZSTD_CStreamOutSize();
@ -268,8 +299,14 @@ static cRess_t FIO_createCResources(const char* dictFileName, int cLevel,
            if (comprParams->searchLength) params.cParams.searchLength = comprParams->searchLength;
            if (comprParams->targetLength) params.cParams.targetLength = comprParams->targetLength;
            if (comprParams->strategy) params.cParams.strategy = (ZSTD_strategy)(comprParams->strategy - 1);
+#ifdef ZSTD_MULTITHREAD
+            {   size_t const errorCode = ZSTDMT_initCStream_advanced(ress.cctx, dictBuffer, dictBuffSize, params, srcSize);
+                if (ZSTD_isError(errorCode)) EXM_THROW(33, "Error initializing CStream : %s", ZSTD_getErrorName(errorCode));
+                ZSTDMT_setMTCtxParameter(ress.cctx, ZSTDMT_p_sectionSize, g_blockSize);
+#else
            {   size_t const errorCode = ZSTD_initCStream_advanced(ress.cctx, dictBuffer, dictBuffSize, params, srcSize);
                if (ZSTD_isError(errorCode)) EXM_THROW(33, "Error initializing CStream : %s", ZSTD_getErrorName(errorCode));
+#endif
        }   }
        free(dictBuffer);
    }
@ -281,7 +318,11 @@ static void FIO_freeCResources(cRess_t ress)
 {
    free(ress.srcBuffer);
    free(ress.dstBuffer);
+#ifdef ZSTD_MULTITHREAD
+    ZSTDMT_freeCCtx(ress.cctx);
+#else
    ZSTD_freeCStream(ress.cctx);   /* never fails */
+#endif
 }


@ -300,7 +341,11 @@ static int FIO_compressFilename_internal(cRess_t ress,
    U64 const fileSize = UTIL_getFileSize(srcFileName);

    /* init */
+#ifdef ZSTD_MULTITHREAD
+    {   size_t const resetError = ZSTDMT_resetCStream(ress.cctx, fileSize);
+#else
    {   size_t const resetError = ZSTD_resetCStream(ress.cctx, fileSize);
+#endif
        if (ZSTD_isError(resetError)) EXM_THROW(21, "Error initializing compression : %s", ZSTD_getErrorName(resetError));
    }

@ -312,31 +357,39 @@ static int FIO_compressFilename_internal(cRess_t ress,
        readsize += inSize;
        DISPLAYUPDATE(2, "\rRead : %u MB  ", (U32)(readsize>>20));

-        /* Compress using buffered streaming */
        {   ZSTD_inBuffer  inBuff = { ress.srcBuffer, inSize, 0 };
-            ZSTD_outBuffer outBuff= { ress.dstBuffer, ress.dstBufferSize, 0 };
-            { size_t const result = ZSTD_compressStream(ress.cctx, &outBuff, &inBuff);
-              if (ZSTD_isError(result)) EXM_THROW(23, "Compression error : %s ", ZSTD_getErrorName(result)); }
-            if (inBuff.pos != inBuff.size)
-                /* inBuff should be entirely consumed since buffer sizes are recommended ones */
-                EXM_THROW(24, "Compression error : input block not fully consumed");
+            while (inBuff.pos != inBuff.size) {   /* note : is there any possibility of endless loop ? for example, if outBuff is not large enough ? */
+                ZSTD_outBuffer outBuff= { ress.dstBuffer, ress.dstBufferSize, 0 };
+#ifdef ZSTD_MULTITHREAD
+                size_t const result = ZSTDMT_compressStream(ress.cctx, &outBuff, &inBuff);
+#else
+                size_t const result = ZSTD_compressStream(ress.cctx, &outBuff, &inBuff);
+#endif
+                if (ZSTD_isError(result)) EXM_THROW(23, "Compression error : %s ", ZSTD_getErrorName(result));

-            /* Write cBlock */
-            { size_t const sizeCheck = fwrite(ress.dstBuffer, 1, outBuff.pos, dstFile);
-              if (sizeCheck!=outBuff.pos) EXM_THROW(25, "Write error : cannot write compressed block into %s", dstFileName); }
-            compressedfilesize += outBuff.pos;
-        }
+                /* Write compressed stream */
+                if (outBuff.pos) {
+                    size_t const sizeCheck = fwrite(ress.dstBuffer, 1, outBuff.pos, dstFile);
+                    if (sizeCheck!=outBuff.pos) EXM_THROW(25, "Write error : cannot write compressed block into %s", dstFileName);
+                    compressedfilesize += outBuff.pos;
+        }   }   }
        DISPLAYUPDATE(2, "\rRead : %u MB  ==> %.2f%%   ", (U32)(readsize>>20), (double)compressedfilesize/readsize*100);
    }

    /* End of Frame */
-    {   ZSTD_outBuffer outBuff = { ress.dstBuffer, ress.dstBufferSize, 0 };
-        size_t const result = ZSTD_endStream(ress.cctx, &outBuff);
-        if (result!=0) EXM_THROW(26, "Compression error : cannot create frame end");
-
-        { size_t const sizeCheck = fwrite(ress.dstBuffer, 1, outBuff.pos, dstFile);
-          if (sizeCheck!=outBuff.pos) EXM_THROW(27, "Write error : cannot write frame end into %s", dstFileName); }
-        compressedfilesize += outBuff.pos;
+    {   size_t result = 1;
+        while (result!=0) {   /* note : is there any possibility of endless loop ? */
+            ZSTD_outBuffer outBuff = { ress.dstBuffer, ress.dstBufferSize, 0 };
+#ifdef ZSTD_MULTITHREAD
+            result = ZSTDMT_endStream(ress.cctx, &outBuff);
+#else
+            result = ZSTD_endStream(ress.cctx, &outBuff);
+#endif
+            if (ZSTD_isError(result)) EXM_THROW(26, "Compression error during frame end : %s", ZSTD_getErrorName(result));
+            { size_t const sizeCheck = fwrite(ress.dstBuffer, 1, outBuff.pos, dstFile);
+              if (sizeCheck!=outBuff.pos) EXM_THROW(27, "Write error : cannot write frame end into %s", dstFileName); }
+            compressedfilesize += outBuff.pos;
+        }
    }

    /* Status */
@ -486,7 +539,7 @@ static dRess_t FIO_createDResources(const char* dictFileName)
    /* Allocation */
    ress.dctx = ZSTD_createDStream();
    if (ress.dctx==NULL) EXM_THROW(60, "Can't create ZSTD_DStream");
-    ZSTD_setDStreamParameter(ress.dctx, ZSTDdsp_maxWindowSize, g_memLimit);
+    ZSTD_setDStreamParameter(ress.dctx, DStream_p_maxWindowSize, g_memLimit);
    ress.srcBufferSize = ZSTD_DStreamInSize();
    ress.srcBuffer = malloc(ress.srcBufferSize);
    ress.dstBufferSize = ZSTD_DStreamOutSize();
@ -637,7 +690,7 @@ unsigned long long FIO_decompressFrame(dRess_t* ress,
        if (ZSTD_isError(readSizeHint)) EXM_THROW(36, "Decoding error : %s", ZSTD_getErrorName(readSizeHint));

        /* Write block */
-        storedSkips = FIO_fwriteSparse(ress->dstFile, ress->dstBuffer, outBuff.pos, storedSkips);       
+        storedSkips = FIO_fwriteSparse(ress->dstFile, ress->dstBuffer, outBuff.pos, storedSkips);
        frameSize += outBuff.pos;
        DISPLAYUPDATE(2, "\rDecoded : %u MB...     ", (U32)((alreadyDecoded+frameSize)>>20) );

--- a/programs/fileio.h
+++ b/programs/fileio.h
@ -12,12 +12,13 @@
 #define FILEIO_H_23981798732

 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
-#include "zstd.h"     /* ZSTD_compressionParameters */
+#include "zstd.h"                  /* ZSTD_* */

 #if defined (__cplusplus)
 extern "C" {
 #endif

+
 /* *************************************
 *  Special i/o constants
 **************************************/
@ -40,6 +41,8 @@ void FIO_setDictIDFlag(unsigned dictIDFlag);
 void FIO_setChecksumFlag(unsigned checksumFlag);
 void FIO_setRemoveSrcFile(unsigned flag);
 void FIO_setMemLimit(unsigned memLimit);
+void FIO_setNbThreads(unsigned nbThreads);
+void FIO_setBlockSize(unsigned blockSize);


 /*-*************************************
--- a/programs/util.h
+++ b/programs/util.h
@ -95,18 +95,26 @@ extern "C" {
 /*-****************************************
 *  Time functions
 ******************************************/
-#if !defined(_WIN32)
-   typedef clock_t UTIL_time_t;
-   UTIL_STATIC void UTIL_initTimer(UTIL_time_t* ticksPerSecond) { *ticksPerSecond=0; }
-   UTIL_STATIC void UTIL_getTime(UTIL_time_t* x) { *x = clock(); }
-   UTIL_STATIC U64 UTIL_getSpanTimeMicro(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { (void)ticksPerSecond; return 1000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
-   UTIL_STATIC U64 UTIL_getSpanTimeNano(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { (void)ticksPerSecond; return 1000000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
-#else
+#if (PLATFORM_POSIX_VERSION >= 1)
+#include <unistd.h>
+#include <sys/times.h>   /* times */
+   typedef U64 UTIL_time_t;
+   UTIL_STATIC void UTIL_initTimer(UTIL_time_t* ticksPerSecond) { *ticksPerSecond=sysconf(_SC_CLK_TCK); }
+   UTIL_STATIC void UTIL_getTime(UTIL_time_t* x) { struct tms junk; clock_t newTicks = (clock_t) times(&junk); (void)junk; *x = (UTIL_time_t)newTicks; }
+   UTIL_STATIC U64 UTIL_getSpanTimeMicro(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000ULL * (clockEnd - clockStart) / ticksPerSecond; }
+   UTIL_STATIC U64 UTIL_getSpanTimeNano(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000000ULL * (clockEnd - clockStart) / ticksPerSecond; }
+#elif defined(_WIN32)   /* Windows */
   typedef LARGE_INTEGER UTIL_time_t;
   UTIL_STATIC void UTIL_initTimer(UTIL_time_t* ticksPerSecond) { if (!QueryPerformanceFrequency(ticksPerSecond)) fprintf(stderr, "ERROR: QueryPerformance not present\n"); }
   UTIL_STATIC void UTIL_getTime(UTIL_time_t* x) { QueryPerformanceCounter(x); }
   UTIL_STATIC U64 UTIL_getSpanTimeMicro(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000ULL*(clockEnd.QuadPart - clockStart.QuadPart)/ticksPerSecond.QuadPart; }
   UTIL_STATIC U64 UTIL_getSpanTimeNano(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000000ULL*(clockEnd.QuadPart - clockStart.QuadPart)/ticksPerSecond.QuadPart; }
+#else   /* relies on standard C (note : clock_t measurements can be wrong when using multi-threading) */
+   typedef clock_t UTIL_time_t;
+   UTIL_STATIC void UTIL_initTimer(UTIL_time_t* ticksPerSecond) { *ticksPerSecond=0; }
+   UTIL_STATIC void UTIL_getTime(UTIL_time_t* x) { *x = clock(); }
+   UTIL_STATIC U64 UTIL_getSpanTimeMicro(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { (void)ticksPerSecond; return 1000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
+   UTIL_STATIC U64 UTIL_getSpanTimeNano(UTIL_time_t ticksPerSecond, UTIL_time_t clockStart, UTIL_time_t clockEnd) { (void)ticksPerSecond; return 1000000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
 #endif


--- a/programs/zstdcli.c
+++ b/programs/zstdcli.c
@ -20,6 +20,7 @@
 #endif


+
 /*-************************************
 *  Dependencies
 **************************************/
@ -110,12 +111,16 @@ static int usage_advanced(const char* programName)
    DISPLAY( " -q     : suppress warnings; specify twice to suppress errors too\n");
    DISPLAY( " -c     : force write to standard output, even if it is the console\n");
 #ifdef UTIL_HAS_CREATEFILELIST
-    DISPLAY( " -r     : operate recursively on directories\n");
+    DISPLAY( " -r     : operate recursively on directories \n");
 #endif
 #ifndef ZSTD_NOCOMPRESS
    DISPLAY( "--ultra : enable levels beyond %i, up to %i (requires more memory)\n", ZSTDCLI_CLEVEL_MAX, ZSTD_maxCLevel());
    DISPLAY( "--no-dictID : don't write dictID into header (dictionary compression)\n");
-    DISPLAY( "--[no-]check : integrity check (default:enabled)\n");
+    DISPLAY( "--[no-]check : integrity check (default:enabled) \n");
+#ifdef ZSTD_MULTITHREAD
+    DISPLAY( " -T#    : use # threads for compression (default:1) \n");
+    DISPLAY( " -B#    : select size of independent sections (default:0==automatic) \n");
+#endif
 #endif
 #ifndef ZSTD_NODECOMPRESS
    DISPLAY( "--test  : test compressed file integrity \n");
@ -256,7 +261,10 @@ int main(int argCount, const char* argv[])
        nextArgumentIsDictID=0,
        nextArgumentsAreFiles=0,
        ultra=0,
-        lastCommand = 0;
+        lastCommand = 0,
+        nbThreads = 1;
+    unsigned bench_nbSeconds = 3;   /* would be better if this value was synchronized from bench */
+    size_t blockSize = 0;
    zstd_operation_mode operation = zom_compress;
    ZSTD_compressionParameters compressionParams;
    int cLevel = ZSTDCLI_CLEVEL_DEFAULT;
@ -393,7 +401,7 @@ int main(int argCount, const char* argv[])
                         /* Decoding */
                    case 'd':
 #ifndef ZSTD_NOBENCH
-                            if (operation==zom_bench) { BMK_setDecodeOnly(1); argument++; break; }  /* benchmark decode (hidden option) */
+                            if (operation==zom_bench) { BMK_setDecodeOnlyMode(1); argument++; break; }  /* benchmark decode (hidden option) */
 #endif
                            operation=zom_decompress; argument++; break;

@ -437,34 +445,38 @@ int main(int argCount, const char* argv[])

 #ifndef ZSTD_NOBENCH
                        /* Benchmark */
-                    case 'b': operation=zom_bench; argument++; break;
+                    case 'b':
+                        operation=zom_bench;
+                        argument++;
+                        break;

                        /* range bench (benchmark only) */
                    case 'e':
-                            /* compression Level */
-                            argument++;
-                            cLevelLast = readU32FromChar(&argument);
-                            break;
+                        /* compression Level */
+                        argument++;
+                        cLevelLast = readU32FromChar(&argument);
+                        break;

                        /* Modify Nb Iterations (benchmark only) */
                    case 'i':
                        argument++;
-                        {   U32 const iters = readU32FromChar(&argument);
-                            BMK_setNotificationLevel(displayLevel);
-                            BMK_SetNbSeconds(iters);
-                        }
+                        bench_nbSeconds = readU32FromChar(&argument);
                        break;

                        /* cut input into blocks (benchmark only) */
                    case 'B':
                        argument++;
-                        {   size_t const bSize = readU32FromChar(&argument);
-                            BMK_setNotificationLevel(displayLevel);
-                            BMK_SetBlockSize(bSize);
-                        }
+                        blockSize = readU32FromChar(&argument);
                        break;
+
 #endif   /* ZSTD_NOBENCH */

+                        /* nb of threads (hidden option) */
+                    case 'T':
+                        argument++;
+                        nbThreads = readU32FromChar(&argument);
+                        break;
+
                        /* Dictionary Selection level */
                    case 's':
                        argument++;
@ -553,6 +565,9 @@ int main(int argCount, const char* argv[])
    if (operation==zom_bench) {
 #ifndef ZSTD_NOBENCH
        BMK_setNotificationLevel(displayLevel);
+        BMK_setBlockSize(blockSize);
+        BMK_setNbThreads(nbThreads);
+        BMK_setNbSeconds(bench_nbSeconds);
        BMK_benchFiles(filenameTable, filenameIdx, dictFileName, cLevel, cLevelLast, &compressionParams);
 #endif
        goto _end;
@ -603,7 +618,7 @@ int main(int argCount, const char* argv[])
    }   }
 #endif

-    /* No warning message in pipe mode (stdin + stdout) or multi-files mode */
+    /* No status message in pipe mode (stdin - stdout) or multi-files mode */
    if (!strcmp(filenameTable[0], stdinmark) && outFileName && !strcmp(outFileName,stdoutmark) && (displayLevel==2)) displayLevel=1;
    if ((filenameIdx>1) & (displayLevel==2)) displayLevel=1;

@ -611,6 +626,8 @@ int main(int argCount, const char* argv[])
    FIO_setNotificationLevel(displayLevel);
    if (operation==zom_compress) {
 #ifndef ZSTD_NOCOMPRESS
+        FIO_setNbThreads(nbThreads);
+        FIO_setBlockSize((U32)blockSize);
        if ((filenameIdx==1) && outFileName)
          operationResult = FIO_compressFilename(outFileName, filenameTable[0], dictFileName, cLevel, &compressionParams);
        else
--- a/tests/.gitignore
+++ b/tests/.gitignore
@ -6,6 +6,7 @@ fuzzer32
 fuzzer-dll
 zbufftest
 zbufftest32
+zbufftest-dll
 zstreamtest
 zstreamtest32
 zstreamtest-dll
@ -15,6 +16,7 @@ paramgrill32
 roundTripCrash
 longmatch
 symbols
+pool
 invalidDictionaries

 # Tmp test directory
--- a/tests/Makefile
+++ b/tests/Makefile
@ -26,10 +26,10 @@ PYTHON ?= python3
 TESTARTEFACT := versionsTest namespaceTest


-CPPFLAGS+= -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/dictBuilder -I$(ZSTDDIR)/deprecated -I$(PRGDIR)
+CPPFLAGS+= -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/compress -I$(ZSTDDIR)/dictBuilder -I$(ZSTDDIR)/deprecated -I$(PRGDIR)
 CFLAGS  ?= -O3
-CFLAGS  += -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow -Wstrict-aliasing=1 \
-          -Wswitch-enum -Wdeclaration-after-statement -Wstrict-prototypes -Wundef
+CFLAGS  += -g -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow -Wstrict-aliasing=1 \
+           -Wswitch-enum -Wdeclaration-after-statement -Wstrict-prototypes -Wundef
 CFLAGS  += $(MOREFLAGS)
 FLAGS    = $(CPPFLAGS) $(CFLAGS) $(LDFLAGS)

@ -46,8 +46,10 @@ ZDICT_FILES := $(ZSTDDIR)/dictBuilder/*.c
 # Define *.exe as extension for Windows systems
 ifneq (,$(filter Windows%,$(OS)))
 EXT =.exe
+MULTITHREAD = -DZSTD_MULTITHREAD
 else
 EXT =
+MULTITHREAD = -pthread -DZSTD_MULTITHREAD
 endif

 VOID = /dev/null
@ -122,10 +124,10 @@ zbufftest-dll : $(ZSTDDIR)/common/xxhash.c $(PRGDIR)/datagen.c zbufftest.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@$(EXT)

 zstreamtest  : $(ZSTD_FILES) $(ZDICT_FILES) $(PRGDIR)/datagen.c zstreamtest.c
-	$(CC)      $(FLAGS) $^ -o $@$(EXT)
+	$(CC)      $(FLAGS) $(MULTITHREAD) $^ -o $@$(EXT)

 zstreamtest32 : $(ZSTD_FILES) $(ZDICT_FILES) $(PRGDIR)/datagen.c zstreamtest.c
-	$(CC) -m32  $(FLAGS) $^ -o $@$(EXT)
+	$(CC) -m32  $(FLAGS) $(MULTITHREAD) $^ -o $@$(EXT)

 zstreamtest-dll : LDFLAGS+= -L$(ZSTDDIR) -lzstd
 zstreamtest-dll : $(ZSTDDIR)/common/xxhash.c $(PRGDIR)/datagen.c zstreamtest.c
@ -156,6 +158,9 @@ else
 	$(CC) $(FLAGS) $^ -o $@$(EXT) -Wl,-rpath=$(ZSTDDIR) $(ZSTDDIR)/libzstd.so
 endif

+pool  : pool.c $(ZSTDDIR)/common/pool.c $(ZSTDDIR)/common/threading.c
+	$(CC)    $(FLAGS) $(MULTITHREAD) $^ -o $@$(EXT)
+
 namespaceTest:
 	if $(CC) namespaceTest.c ../lib/common/xxhash.c -o $@ ; then echo compilation should fail; exit 1 ; fi
 	$(RM) $@
@ -174,7 +179,7 @@ clean:
        fuzzer-dll$(EXT) zstreamtest-dll$(EXT) zbufftest-dll$(EXT)\
        zstreamtest$(EXT) zstreamtest32$(EXT) \
        datagen$(EXT) paramgrill$(EXT) roundTripCrash$(EXT) longmatch$(EXT) \
-        symbols$(EXT) invalidDictionaries$(EXT)
+        symbols$(EXT) invalidDictionaries$(EXT) pool$(EXT)
 	@echo Cleaning completed


@ -220,7 +225,7 @@ zstd-playTests: datagen
 	file $(ZSTD)
 	ZSTD="$(QEMU_SYS) $(ZSTD)" ./playTests.sh $(ZSTDRTTEST)

-test: test-zstd test-fullbench test-fuzzer test-zstream test-longmatch test-invalidDictionaries
+test: test-zstd test-fullbench test-fuzzer test-zstream test-longmatch test-invalidDictionaries test-pool

 test32: test-zstd32 test-fullbench32 test-fuzzer32 test-zstream32

@ -286,4 +291,7 @@ test-invalidDictionaries: invalidDictionaries
 test-symbols: symbols
 	$(QEMU_SYS) ./symbols

+test-pool: pool
+	$(QEMU_SYS) ./pool
+
 endif
--- a/tests/fuzzer.c
+++ b/tests/fuzzer.c
@ -755,6 +755,7 @@ static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxD
                CHECK (ZSTD_isError(errorCode), "ZSTD_copyCCtx error : %s", ZSTD_getErrorName(errorCode));
        }   }
        XXH64_reset(&xxhState, 0);
+        ZSTD_setCCtxParameter(ctx, ZSTD_p_forceWindow, FUZ_rand(&lseed) & 1);
        {   U32 const nbChunks = (FUZ_rand(&lseed) & 127) + 2;
            U32 n;
            for (totalTestSize=0, cSize=0, n=0 ; n<nbChunks ; n++) {
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@ -135,14 +135,14 @@ $ZSTD -c world.tmp > world.zstd
 cat hello.zstd world.zstd > helloworld.zstd
 $ZSTD -dc helloworld.zstd > result.tmp
 cat result.tmp
-sdiff helloworld.tmp result.tmp
+$DIFF helloworld.tmp result.tmp
 $ECHO "frame concatenation without checksum"
 $ZSTD -c hello.tmp > hello.zstd --no-check
 $ZSTD -c world.tmp > world.zstd --no-check
 cat hello.zstd world.zstd > helloworld.zstd
 $ZSTD -dc helloworld.zstd > result.tmp
 cat result.tmp
-sdiff helloworld.tmp result.tmp
+$DIFF helloworld.tmp result.tmp
 rm ./*.tmp ./*.zstd
 $ECHO "frame concatenation tests completed"

--- a/tests/pool.c
+++ b/tests/pool.c
@ -0,0 +1,70 @@
+#include "pool.h"
+#include "threading.h"
+#include <stddef.h>
+#include <stdio.h>
+
+#define ASSERT_TRUE(p)                                                         \
+  do {                                                                         \
+    if (!(p)) {                                                                \
+      return 1;                                                                \
+    }                                                                          \
+  } while (0)
+#define ASSERT_FALSE(p) ASSERT_TRUE(!(p))
+#define ASSERT_EQ(lhs, rhs) ASSERT_TRUE((lhs) == (rhs))
+
+struct data {
+  pthread_mutex_t mutex;
+  unsigned data[16];
+  size_t i;
+};
+
+void fn(void *opaque) {
+  struct data *data = (struct data *)opaque;
+  pthread_mutex_lock(&data->mutex);
+  data->data[data->i] = data->i;
+  ++data->i;
+  pthread_mutex_unlock(&data->mutex);
+}
+
+int testOrder(size_t numThreads, size_t queueSize) {
+  struct data data;
+  POOL_ctx *ctx = POOL_create(numThreads, queueSize);
+  ASSERT_TRUE(ctx);
+  data.i = 0;
+  pthread_mutex_init(&data.mutex, NULL);
+  {
+    size_t i;
+    for (i = 0; i < 16; ++i) {
+      POOL_add(ctx, &fn, &data);
+    }
+  }
+  POOL_free(ctx);
+  ASSERT_EQ(16, data.i);
+  {
+    size_t i;
+    for (i = 0; i < data.i; ++i) {
+      ASSERT_EQ(i, data.data[i]);
+    }
+  }
+  pthread_mutex_destroy(&data.mutex);
+  return 0;
+}
+
+int main(int argc, const char **argv) {
+  size_t numThreads;
+  for (numThreads = 1; numThreads <= 4; ++numThreads) {
+    size_t queueSize;
+    for (queueSize = 1; queueSize <= 2; ++queueSize) {
+      if (testOrder(numThreads, queueSize)) {
+        printf("FAIL: testOrder\n");
+        return 1;
+      }
+    }
+  }
+  printf("PASS: testOrder\n");
+  (void)argc;
+  (void)argv;
+  return (POOL_create(0, 1) || POOL_create(1, 0)) ? printf("FAIL: testInvalid\n"), 1
+                                                  : printf("PASS: testInvalid\n"), 0;
+  return 0;
+}
--- a/tests/zstreamtest.c
+++ b/tests/zstreamtest.c
@ -29,6 +29,7 @@
 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_maxCLevel, ZSTD_customMem, ZSTD_getDictID_fromFrame */
 #include "zstd.h"         /* ZSTD_compressBound */
 #include "zstd_errors.h"  /* ZSTD_error_srcSize_wrong */
+#include "zstdmt_compress.h"
 #include "zdict.h"        /* ZDICT_trainFromBuffer */
 #include "datagen.h"      /* RDG_genBuffer */
 #define XXH_STATIC_LINKING_ONLY   /* XXH64_state_t */
@ -184,7 +185,7 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
    cSize = skippableFrameSize + 8;

    /* Basic compression test */
-    DISPLAYLEVEL(4, "test%3i : compress %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH);
+    DISPLAYLEVEL(3, "test%3i : compress %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH);
    ZSTD_initCStream_usingDict(zc, CNBuffer, 128 KB, 1);
    outBuff.dst = (char*)(compressedBuffer)+cSize;
    outBuff.size = compressedBufferSize;
@ -198,16 +199,16 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
    { size_t const r = ZSTD_endStream(zc, &outBuff);
      if (r != 0) goto _output_error; }  /* error, or some data not flushed */
    cSize += outBuff.pos;
-    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/COMPRESSIBLE_NOISE_LENGTH*100);
+    DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/COMPRESSIBLE_NOISE_LENGTH*100);

-    DISPLAYLEVEL(4, "test%3i : check CStream size : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : check CStream size : ", testNb++);
    { size_t const s = ZSTD_sizeof_CStream(zc);
      if (ZSTD_isError(s)) goto _output_error;
-      DISPLAYLEVEL(4, "OK (%u bytes) \n", (U32)s);
+      DISPLAYLEVEL(3, "OK (%u bytes) \n", (U32)s);
    }

    /* skippable frame test */
-    DISPLAYLEVEL(4, "test%3i : decompress skippable frame : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress skippable frame : ", testNb++);
    ZSTD_initDStream_usingDict(zd, CNBuffer, 128 KB);
    inBuff.src = compressedBuffer;
    inBuff.size = cSize;
@ -218,45 +219,45 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
    { size_t const r = ZSTD_decompressStream(zd, &outBuff, &inBuff);
      if (r != 0) goto _output_error; }
    if (outBuff.pos != 0) goto _output_error;   /* skippable frame len is 0 */
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

    /* Basic decompression test */
    inBuff2 = inBuff;
-    DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH);
+    DISPLAYLEVEL(3, "test%3i : decompress %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH);
    ZSTD_initDStream_usingDict(zd, CNBuffer, 128 KB);
-    { size_t const r = ZSTD_setDStreamParameter(zd, ZSTDdsp_maxWindowSize, 1000000000);  /* large limit */
+    { size_t const r = ZSTD_setDStreamParameter(zd, DStream_p_maxWindowSize, 1000000000);  /* large limit */
      if (ZSTD_isError(r)) goto _output_error; }
    { size_t const remaining = ZSTD_decompressStream(zd, &outBuff, &inBuff);
      if (remaining != 0) goto _output_error; }  /* should reach end of frame == 0; otherwise, some data left, or an error */
    if (outBuff.pos != CNBufferSize) goto _output_error;   /* should regenerate the same amount */
    if (inBuff.pos != inBuff.size) goto _output_error;   /* should have read the entire frame */
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

    /* Re-use without init */
-    DISPLAYLEVEL(4, "test%3i : decompress again without init (re-use previous settings): ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress again without init (re-use previous settings): ", testNb++);
    outBuff.pos = 0;
    { size_t const remaining = ZSTD_decompressStream(zd, &outBuff, &inBuff2);
      if (remaining != 0) goto _output_error; }  /* should reach end of frame == 0; otherwise, some data left, or an error */
    if (outBuff.pos != CNBufferSize) goto _output_error;   /* should regenerate the same amount */
    if (inBuff.pos != inBuff.size) goto _output_error;   /* should have read the entire frame */
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

    /* check regenerated data is byte exact */
-    DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : check decompressed result : ", testNb++);
    {   size_t i;
        for (i=0; i<CNBufferSize; i++) {
            if (((BYTE*)decodedBuffer)[i] != ((BYTE*)CNBuffer)[i]) goto _output_error;
    }   }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

-    DISPLAYLEVEL(4, "test%3i : check DStream size : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : check DStream size : ", testNb++);
    { size_t const s = ZSTD_sizeof_DStream(zd);
      if (ZSTD_isError(s)) goto _output_error;
-      DISPLAYLEVEL(4, "OK (%u bytes) \n", (U32)s);
+      DISPLAYLEVEL(3, "OK (%u bytes) \n", (U32)s);
    }

    /* Byte-by-byte decompression test */
-    DISPLAYLEVEL(4, "test%3i : decompress byte-by-byte : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : decompress byte-by-byte : ", testNb++);
    {   /* skippable frame */
        size_t r = 1;
        ZSTD_initDStream_usingDict(zd, CNBuffer, 128 KB);
@ -282,18 +283,18 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
    }
    if (outBuff.pos != CNBufferSize) goto _output_error;   /* should regenerate the same amount */
    if (inBuff.pos != cSize) goto _output_error;   /* should have read the entire frame */
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

    /* check regenerated data is byte exact */
-    DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : check decompressed result : ", testNb++);
    {   size_t i;
        for (i=0; i<CNBufferSize; i++) {
            if (((BYTE*)decodedBuffer)[i] != ((BYTE*)CNBuffer)[i]) goto _output_error;;
    }   }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

    /* _srcSize compression test */
-    DISPLAYLEVEL(4, "test%3i : compress_srcSize %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH);
+    DISPLAYLEVEL(3, "test%3i : compress_srcSize %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH);
    ZSTD_initCStream_srcSize(zc, 1, CNBufferSize);
    outBuff.dst = (char*)(compressedBuffer);
    outBuff.size = compressedBufferSize;
@ -308,10 +309,10 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
      if (r != 0) goto _output_error; }  /* error, or some data not flushed */
    { unsigned long long origSize = ZSTD_getDecompressedSize(outBuff.dst, outBuff.pos);
      if ((size_t)origSize != CNBufferSize) goto _output_error; }  /* exact original size must be present */
-    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/COMPRESSIBLE_NOISE_LENGTH*100);
+    DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/COMPRESSIBLE_NOISE_LENGTH*100);

    /* wrong _srcSize compression test */
-    DISPLAYLEVEL(4, "test%3i : wrong srcSize : %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH-1);
+    DISPLAYLEVEL(3, "test%3i : wrong srcSize : %u bytes : ", testNb++, COMPRESSIBLE_NOISE_LENGTH-1);
    ZSTD_initCStream_srcSize(zc, 1, CNBufferSize-1);
    outBuff.dst = (char*)(compressedBuffer);
    outBuff.size = compressedBufferSize;
@ -324,10 +325,10 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
    if (inBuff.pos != inBuff.size) goto _output_error;   /* entire input should be consumed */
    { size_t const r = ZSTD_endStream(zc, &outBuff);
      if (ZSTD_getErrorCode(r) != ZSTD_error_srcSize_wrong) goto _output_error;    /* must fail : wrong srcSize */
-      DISPLAYLEVEL(4, "OK (error detected : %s) \n", ZSTD_getErrorName(r)); }
+      DISPLAYLEVEL(3, "OK (error detected : %s) \n", ZSTD_getErrorName(r)); }

    /* Complex context re-use scenario */
-    DISPLAYLEVEL(4, "test%3i : context re-use : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : context re-use : ", testNb++);
    ZSTD_freeCStream(zc);
    zc = ZSTD_createCStream_advanced(customMem);
    if (zc==NULL) goto _output_error;   /* memory allocation issue */
@ -361,10 +362,10 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
        { size_t const r = ZSTD_endStream(zc, &outBuff);
            if (r != 0) goto _output_error; }  /* error, or some data not flushed */
    }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

    /* CDict scenario */
-    DISPLAYLEVEL(4, "test%3i : digested dictionary : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : digested dictionary : ", testNb++);
    {   ZSTD_CDict* const cdict = ZSTD_createCDict(dictionary.start, dictionary.filled, 1);
        size_t const initError = ZSTD_initCStream_usingCDict(zc, cdict);
        if (ZSTD_isError(initError)) goto _output_error;
@ -382,13 +383,13 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
          if (r != 0) goto _output_error; }  /* error, or some data not flushed */
        cSize = outBuff.pos;
        ZSTD_freeCDict(cdict);
-        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBufferSize*100);
+        DISPLAYLEVEL(3, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBufferSize*100);
    }

-    DISPLAYLEVEL(4, "test%3i : check CStream size : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : check CStream size : ", testNb++);
    { size_t const s = ZSTD_sizeof_CStream(zc);
      if (ZSTD_isError(s)) goto _output_error;
-      DISPLAYLEVEL(4, "OK (%u bytes) \n", (U32)s);
+      DISPLAYLEVEL(3, "OK (%u bytes) \n", (U32)s);
    }

    DISPLAYLEVEL(4, "test%3i : check Dictionary ID : ", testNb++);
@ -398,7 +399,7 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
    }

    /* DDict scenario */
-    DISPLAYLEVEL(4, "test%3i : decompress %u bytes with digested dictionary : ", testNb++, (U32)CNBufferSize);
+    DISPLAYLEVEL(3, "test%3i : decompress %u bytes with digested dictionary : ", testNb++, (U32)CNBufferSize);
    {   ZSTD_DDict* const ddict = ZSTD_createDDict(dictionary.start, dictionary.filled);
        size_t const initError = ZSTD_initDStream_usingDDict(zd, ddict);
        if (ZSTD_isError(initError)) goto _output_error;
@ -413,19 +414,19 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
        if (outBuff.pos != CNBufferSize) goto _output_error;   /* should regenerate the same amount */
        if (inBuff.pos != inBuff.size) goto _output_error;   /* should have read the entire frame */
        ZSTD_freeDDict(ddict);
-        DISPLAYLEVEL(4, "OK \n");
+        DISPLAYLEVEL(3, "OK \n");
    }

    /* test ZSTD_setDStreamParameter() resilience */
-    DISPLAYLEVEL(4, "test%3i : wrong parameter for ZSTD_setDStreamParameter(): ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : wrong parameter for ZSTD_setDStreamParameter(): ", testNb++);
    { size_t const r = ZSTD_setDStreamParameter(zd, (ZSTD_DStreamParameter_e)999, 1);  /* large limit */
      if (!ZSTD_isError(r)) goto _output_error; }
-    DISPLAYLEVEL(4, "OK \n");
+    DISPLAYLEVEL(3, "OK \n");

    /* Memory restriction */
-    DISPLAYLEVEL(4, "test%3i : maxWindowSize < frame requirement : ", testNb++);
+    DISPLAYLEVEL(3, "test%3i : maxWindowSize < frame requirement : ", testNb++);
    ZSTD_initDStream_usingDict(zd, CNBuffer, 128 KB);
-    { size_t const r = ZSTD_setDStreamParameter(zd, ZSTDdsp_maxWindowSize, 1000);  /* too small limit */
+    { size_t const r = ZSTD_setDStreamParameter(zd, DStream_p_maxWindowSize, 1000);  /* too small limit */
      if (ZSTD_isError(r)) goto _output_error; }
    inBuff.src = compressedBuffer;
    inBuff.size = cSize;
@ -435,7 +436,7 @@ static int basicUnitTests(U32 seed, double compressibility, ZSTD_customMem custo
    outBuff.pos = 0;
    { size_t const r = ZSTD_decompressStream(zd, &outBuff, &inBuff);
      if (!ZSTD_isError(r)) goto _output_error;  /* must fail : frame requires > 100 bytes */
-      DISPLAYLEVEL(4, "OK (%s)\n", ZSTD_getErrorName(r)); }
+      DISPLAYLEVEL(3, "OK (%s)\n", ZSTD_getErrorName(r)); }


 _end:
@ -464,6 +465,11 @@ static size_t findDiff(const void* buf1, const void* buf2, size_t max)
    for (u=0; u<max; u++) {
        if (b1[u] != b2[u]) break;
    }
+    DISPLAY("Error at position %u / %u \n", (U32)u, (U32)max);
+    DISPLAY(" %02X %02X %02X  :%02X:  %02X %02X %02X %02X %02X \n",
+            b1[u-3], b1[u-2], b1[u-1], b1[u-0], b1[u+1], b1[u+2], b1[u+3], b1[u+4], b1[u+5]);
+    DISPLAY(" %02X %02X %02X  :%02X:  %02X %02X %02X %02X %02X \n",
+            b2[u-3], b2[u-2], b2[u-1], b2[u-0], b2[u+1], b2[u+2], b2[u+3], b2[u+4], b2[u+5]);
    return u;
 }

@ -712,6 +718,248 @@ _output_error:
 }


+/* Multi-threading version of fuzzer Tests */
+static int fuzzerTests_MT(U32 seed, U32 nbTests, unsigned startTest, double compressibility)
+{
+    static const U32 maxSrcLog = 24;
+    static const U32 maxSampleLog = 19;
+    size_t const srcBufferSize = (size_t)1<<maxSrcLog;
+    BYTE* cNoiseBuffer[5];
+    size_t const copyBufferSize= srcBufferSize + (1<<maxSampleLog);
+    BYTE*  const copyBuffer = (BYTE*)malloc (copyBufferSize);
+    size_t const cBufferSize   = ZSTD_compressBound(srcBufferSize);
+    BYTE*  const cBuffer = (BYTE*)malloc (cBufferSize);
+    size_t const dstBufferSize = srcBufferSize;
+    BYTE*  const dstBuffer = (BYTE*)malloc (dstBufferSize);
+    U32 result = 0;
+    U32 testNb = 0;
+    U32 coreSeed = seed;
+    ZSTDMT_CCtx* zc = ZSTDMT_createCCtx(2);   /* will be reset sometimes */
+    ZSTD_DStream* zd = ZSTD_createDStream();   /* will be reset sometimes */
+    ZSTD_DStream* const zd_noise = ZSTD_createDStream();
+    clock_t const startClock = clock();
+    const BYTE* dict=NULL;   /* can keep same dict on 2 consecutive tests */
+    size_t dictSize = 0;
+    U32 oldTestLog = 0;
+
+    /* allocations */
+    cNoiseBuffer[0] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[1] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[2] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[3] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[4] = (BYTE*)malloc (srcBufferSize);
+    CHECK (!cNoiseBuffer[0] || !cNoiseBuffer[1] || !cNoiseBuffer[2] || !cNoiseBuffer[3] || !cNoiseBuffer[4] ||
+           !copyBuffer || !dstBuffer || !cBuffer || !zc || !zd || !zd_noise ,
+           "Not enough memory, fuzzer tests cancelled");
+
+    /* Create initial samples */
+    RDG_genBuffer(cNoiseBuffer[0], srcBufferSize, 0.00, 0., coreSeed);    /* pure noise */
+    RDG_genBuffer(cNoiseBuffer[1], srcBufferSize, 0.05, 0., coreSeed);    /* barely compressible */
+    RDG_genBuffer(cNoiseBuffer[2], srcBufferSize, compressibility, 0., coreSeed);
+    RDG_genBuffer(cNoiseBuffer[3], srcBufferSize, 0.95, 0., coreSeed);    /* highly compressible */
+    RDG_genBuffer(cNoiseBuffer[4], srcBufferSize, 1.00, 0., coreSeed);    /* sparse content */
+    memset(copyBuffer, 0x65, copyBufferSize);                             /* make copyBuffer considered initialized */
+    ZSTD_initDStream_usingDict(zd, NULL, 0);  /* ensure at least one init */
+
+    /* catch up testNb */
+    for (testNb=1; testNb < startTest; testNb++)
+        FUZ_rand(&coreSeed);
+
+    /* test loop */
+    for ( ; (testNb <= nbTests) || (FUZ_GetClockSpan(startClock) < g_clockTime) ; testNb++ ) {
+        U32 lseed;
+        const BYTE* srcBuffer;
+        size_t totalTestSize, totalGenSize, cSize;
+        XXH64_state_t xxhState;
+        U64 crcOrig;
+        U32 resetAllowed = 1;
+        size_t maxTestSize;
+
+        /* init */
+        if (nbTests >= testNb) { DISPLAYUPDATE(2, "\r%6u/%6u    ", testNb, nbTests); }
+        else { DISPLAYUPDATE(2, "\r%6u          ", testNb); }
+        FUZ_rand(&coreSeed);
+        lseed = coreSeed ^ prime32;
+
+        /* states full reset (deliberately not synchronized) */
+        /* some issues can only happen when reusing states */
+        if ((FUZ_rand(&lseed) & 0xFF) == 131) {
+            U32 const nbThreads = (FUZ_rand(&lseed) % 6) + 1;
+            ZSTDMT_freeCCtx(zc);
+            zc = ZSTDMT_createCCtx(nbThreads);
+            resetAllowed=0;
+        }
+        if ((FUZ_rand(&lseed) & 0xFF) == 132) {
+            ZSTD_freeDStream(zd);
+            zd = ZSTD_createDStream();
+            ZSTD_initDStream_usingDict(zd, NULL, 0);  /* ensure at least one init */
+        }
+
+        /* srcBuffer selection [0-4] */
+        {   U32 buffNb = FUZ_rand(&lseed) & 0x7F;
+            if (buffNb & 7) buffNb=2;   /* most common : compressible (P) */
+            else {
+                buffNb >>= 3;
+                if (buffNb & 7) {
+                    const U32 tnb[2] = { 1, 3 };   /* barely/highly compressible */
+                    buffNb = tnb[buffNb >> 3];
+                } else {
+                    const U32 tnb[2] = { 0, 4 };   /* not compressible / sparse */
+                    buffNb = tnb[buffNb >> 3];
+            }   }
+            srcBuffer = cNoiseBuffer[buffNb];
+        }
+
+        /* compression init */
+        if ((FUZ_rand(&lseed)&1) /* at beginning, to keep same nb of rand */
+            && oldTestLog /* at least one test happened */ && resetAllowed) {
+            maxTestSize = FUZ_randomLength(&lseed, oldTestLog+2);
+            if (maxTestSize >= srcBufferSize) maxTestSize = srcBufferSize-1;
+            {   int const compressionLevel = (FUZ_rand(&lseed) % 5) + 1;
+                size_t const resetError = ZSTDMT_initCStream(zc, compressionLevel);
+                CHECK(ZSTD_isError(resetError), "ZSTDMT_initCStream error : %s", ZSTD_getErrorName(resetError));
+            }
+        } else {
+            U32 const testLog = FUZ_rand(&lseed) % maxSrcLog;
+            U32 const cLevel = (FUZ_rand(&lseed) % (ZSTD_maxCLevel() - (testLog/3))) + 1;
+            maxTestSize = FUZ_rLogLength(&lseed, testLog);
+            oldTestLog = testLog;
+            /* random dictionary selection */
+            dictSize  = ((FUZ_rand(&lseed)&63)==1) ? FUZ_randomLength(&lseed, maxSampleLog) : 0;
+            {   size_t const dictStart = FUZ_rand(&lseed) % (srcBufferSize - dictSize);
+                dict = srcBuffer + dictStart;
+            }
+            {   U64 const pledgedSrcSize = (FUZ_rand(&lseed) & 3) ? 0 : maxTestSize;
+                ZSTD_parameters params = ZSTD_getParams(cLevel, pledgedSrcSize, dictSize);
+                DISPLAYLEVEL(5, "Init with windowLog = %u \n", params.cParams.windowLog);
+                params.fParams.checksumFlag = FUZ_rand(&lseed) & 1;
+                params.fParams.noDictIDFlag = FUZ_rand(&lseed) & 1;
+                {   size_t const initError = ZSTDMT_initCStream_advanced(zc, dict, dictSize, params, pledgedSrcSize);
+                    CHECK (ZSTD_isError(initError),"ZSTDMT_initCStream_advanced error : %s", ZSTD_getErrorName(initError));
+        }   }   }
+
+        /* multi-segments compression test */
+        XXH64_reset(&xxhState, 0);
+        {   ZSTD_outBuffer outBuff = { cBuffer, cBufferSize, 0 } ;
+            U32 n;
+            for (n=0, cSize=0, totalTestSize=0 ; totalTestSize < maxTestSize ; n++) {
+                /* compress random chunks into randomly sized dst buffers */
+                {   size_t const randomSrcSize = FUZ_randomLength(&lseed, maxSampleLog);
+                    size_t const srcSize = MIN (maxTestSize-totalTestSize, randomSrcSize);
+                    size_t const srcStart = FUZ_rand(&lseed) % (srcBufferSize - srcSize);
+                    size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog);
+                    size_t const dstBuffSize = MIN(cBufferSize - cSize, randomDstSize);
+                    ZSTD_inBuffer inBuff = { srcBuffer+srcStart, srcSize, 0 };
+                    outBuff.size = outBuff.pos + dstBuffSize;
+
+                    DISPLAYLEVEL(5, "Sending %u bytes to compress \n", (U32)srcSize);
+                    { size_t const compressionError = ZSTDMT_compressStream(zc, &outBuff, &inBuff);
+                      CHECK (ZSTD_isError(compressionError), "compression error : %s", ZSTD_getErrorName(compressionError)); }
+                    DISPLAYLEVEL(5, "%u bytes read by ZSTDMT_compressStream \n", (U32)inBuff.pos);
+
+                    XXH64_update(&xxhState, srcBuffer+srcStart, inBuff.pos);
+                    memcpy(copyBuffer+totalTestSize, srcBuffer+srcStart, inBuff.pos);
+                    totalTestSize += inBuff.pos;
+                }
+
+                /* random flush operation, to mess around */
+                if ((FUZ_rand(&lseed) & 15) == 0) {
+                    size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog);
+                    size_t const adjustedDstSize = MIN(cBufferSize - cSize, randomDstSize);
+                    outBuff.size = outBuff.pos + adjustedDstSize;
+                    DISPLAYLEVEL(5, "Flushing into dst buffer of size %u \n", (U32)adjustedDstSize);
+                    {   size_t const flushError = ZSTDMT_flushStream(zc, &outBuff);
+                        CHECK (ZSTD_isError(flushError), "flush error : %s", ZSTD_getErrorName(flushError));
+            }   }   }
+
+            /* final frame epilogue */
+            {   size_t remainingToFlush = (size_t)(-1);
+                while (remainingToFlush) {
+                    size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog);
+                    size_t const adjustedDstSize = MIN(cBufferSize - cSize, randomDstSize);
+                    outBuff.size = outBuff.pos + adjustedDstSize;
+                    DISPLAYLEVEL(5, "Ending into dst buffer of size %u \n", (U32)adjustedDstSize);
+                    remainingToFlush = ZSTDMT_endStream(zc, &outBuff);
+                    CHECK (ZSTD_isError(remainingToFlush), "flush error : %s", ZSTD_getErrorName(remainingToFlush));
+                    DISPLAYLEVEL(5, "endStream : remainingToFlush : %u \n", (U32)remainingToFlush);
+            }   }
+            DISPLAYLEVEL(5, "Frame completed \n");
+            crcOrig = XXH64_digest(&xxhState);
+            cSize = outBuff.pos;
+        }
+
+        /* multi - fragments decompression test */
+        if (!dictSize /* don't reset if dictionary : could be different */ && (FUZ_rand(&lseed) & 1)) {
+            CHECK (ZSTD_isError(ZSTD_resetDStream(zd)), "ZSTD_resetDStream failed");
+        } else {
+            ZSTD_initDStream_usingDict(zd, dict, dictSize);
+        }
+        {   size_t decompressionResult = 1;
+            ZSTD_inBuffer  inBuff = { cBuffer, cSize, 0 };
+            ZSTD_outBuffer outBuff= { dstBuffer, dstBufferSize, 0 };
+            for (totalGenSize = 0 ; decompressionResult ; ) {
+                size_t const readCSrcSize = FUZ_randomLength(&lseed, maxSampleLog);
+                size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog);
+                size_t const dstBuffSize = MIN(dstBufferSize - totalGenSize, randomDstSize);
+                inBuff.size = inBuff.pos + readCSrcSize;
+                outBuff.size = inBuff.pos + dstBuffSize;
+                decompressionResult = ZSTD_decompressStream(zd, &outBuff, &inBuff);
+                CHECK (ZSTD_isError(decompressionResult), "decompression error : %s", ZSTD_getErrorName(decompressionResult));
+            }
+            CHECK (outBuff.pos != totalTestSize, "decompressed data : wrong size (%u != %u)", (U32)outBuff.pos, (U32)totalTestSize);
+            CHECK (inBuff.pos != cSize, "compressed data should be fully read (%u != %u)", (U32)inBuff.pos, (U32)cSize);
+            {   U64 const crcDest = XXH64(dstBuffer, totalTestSize, 0);
+                if (crcDest!=crcOrig) findDiff(copyBuffer, dstBuffer, totalTestSize);
+                CHECK (crcDest!=crcOrig, "decompressed data corrupted");
+        }   }
+
+        /*=====   noisy/erroneous src decompression test   =====*/
+
+        /* add some noise */
+        {   U32 const nbNoiseChunks = (FUZ_rand(&lseed) & 7) + 2;
+            U32 nn; for (nn=0; nn<nbNoiseChunks; nn++) {
+                size_t const randomNoiseSize = FUZ_randomLength(&lseed, maxSampleLog);
+                size_t const noiseSize  = MIN((cSize/3) , randomNoiseSize);
+                size_t const noiseStart = FUZ_rand(&lseed) % (srcBufferSize - noiseSize);
+                size_t const cStart = FUZ_rand(&lseed) % (cSize - noiseSize);
+                memcpy(cBuffer+cStart, srcBuffer+noiseStart, noiseSize);
+        }   }
+
+        /* try decompression on noisy data */
+        ZSTD_initDStream(zd_noise);   /* note : no dictionary */
+        {   ZSTD_inBuffer  inBuff = { cBuffer, cSize, 0 };
+            ZSTD_outBuffer outBuff= { dstBuffer, dstBufferSize, 0 };
+            while (outBuff.pos < dstBufferSize) {
+                size_t const randomCSrcSize = FUZ_randomLength(&lseed, maxSampleLog);
+                size_t const randomDstSize = FUZ_randomLength(&lseed, maxSampleLog);
+                size_t const adjustedDstSize = MIN(dstBufferSize - outBuff.pos, randomDstSize);
+                outBuff.size = outBuff.pos + adjustedDstSize;
+                inBuff.size  = inBuff.pos + randomCSrcSize;
+                {   size_t const decompressError = ZSTD_decompressStream(zd, &outBuff, &inBuff);
+                    if (ZSTD_isError(decompressError)) break;   /* error correctly detected */
+    }   }   }   }
+    DISPLAY("\r%u fuzzer tests completed   \n", testNb);
+
+_cleanup:
+    ZSTDMT_freeCCtx(zc);
+    ZSTD_freeDStream(zd);
+    ZSTD_freeDStream(zd_noise);
+    free(cNoiseBuffer[0]);
+    free(cNoiseBuffer[1]);
+    free(cNoiseBuffer[2]);
+    free(cNoiseBuffer[3]);
+    free(cNoiseBuffer[4]);
+    free(copyBuffer);
+    free(cBuffer);
+    free(dstBuffer);
+    return result;
+
+_output_error:
+    result = 1;
+    goto _cleanup;
+}
+
+
 /*-*******************************************************
 *  Command line
 *********************************************************/
@ -741,10 +989,11 @@ int main(int argc, const char** argv)
    int testNb = 0;
    int proba = FUZ_COMPRESSIBILITY_DEFAULT;
    int result=0;
-    U32 mainPause = 0;
-    const char* programName = argv[0];
-    ZSTD_customMem customMem = { allocFunction, freeFunction, NULL };
-    ZSTD_customMem customNULL = { NULL, NULL, NULL };
+    int mainPause = 0;
+    int mtOnly = 0;
+    const char* const programName = argv[0];
+    ZSTD_customMem const customMem = { allocFunction, freeFunction, NULL };
+    ZSTD_customMem const customNULL = { NULL, NULL, NULL };

    /* Check command line */
    for(argNb=1; argNb<argc; argNb++) {
@ -753,27 +1002,32 @@ int main(int argc, const char** argv)

        /* Parsing commands. Aggregated commands are allowed */
        if (argument[0]=='-') {
-            argument++;

+            if (!strcmp(argument, "--mt")) { mtOnly=1; continue; }
+
+            argument++;
            while (*argument!=0) {
                switch(*argument)
                {
                case 'h':
                    return FUZ_usage(programName);
+
                case 'v':
                    argument++;
-                    g_displayLevel=4;
+                    g_displayLevel++;
                    break;
+
                case 'q':
                    argument++;
                    g_displayLevel--;
                    break;
+
                case 'p': /* pause at the end */
                    argument++;
                    mainPause = 1;
                    break;

-                case 'i':
+                case 'i':   /* limit tests by nb of iterations (default) */
                    argument++;
                    nbTests=0; g_clockTime=0;
                    while ((*argument>='0') && (*argument<='9')) {
@ -783,7 +1037,7 @@ int main(int argc, const char** argv)
                    }
                    break;

-                case 'T':
+                case 'T':   /* limit tests by time */
                    argument++;
                    nbTests=0; g_clockTime=0;
                    while ((*argument>='0') && (*argument<='9')) {
@ -796,7 +1050,7 @@ int main(int argc, const char** argv)
                    g_clockTime *= CLOCKS_PER_SEC;
                    break;

-                case 's':
+                case 's':   /* manually select seed */
                    argument++;
                    seed=0;
                    seedset=1;
@ -807,7 +1061,7 @@ int main(int argc, const char** argv)
                    }
                    break;

-                case 't':
+                case 't':   /* select starting test number */
                    argument++;
                    testNb=0;
                    while ((*argument>='0') && (*argument<='9')) {
@ -851,12 +1105,12 @@ int main(int argc, const char** argv)
    if (testNb==0) {
        result = basicUnitTests(0, ((double)proba) / 100, customNULL);  /* constant seed for predictability */
        if (!result) {
-            DISPLAYLEVEL(4, "Unit tests using customMem :\n")
+            DISPLAYLEVEL(3, "Unit tests using customMem :\n")
            result = basicUnitTests(0, ((double)proba) / 100, customMem);  /* use custom memory allocation functions */
    }   }

-    if (!result)
-        result = fuzzerTests(seed, nbTests, testNb, ((double)proba) / 100);
+    if (!result && !mtOnly) result = fuzzerTests(seed, nbTests, testNb, ((double)proba) / 100);
+    if (!result) result = fuzzerTests_MT(seed, nbTests, testNb, ((double)proba) / 100);

    if (mainPause) {
        int unused;