From 9416195221552d6fc8b44b899360d3d14f7401ea Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Wed, 27 Sep 2017 10:35:56 -0700
Subject: [PATCH] changed error code when pos<=size condition is not respected

Now pointing towards src_size or dst_size,
instead of error_GENERIC.
---
 lib/common/error_private.c       | 5 +++--
 lib/common/zstd_errors.h         | 3 ++-
 lib/decompress/zstd_decompress.c | 4 ++--
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/common/error_private.c b/lib/common/error_private.c
index 8045e445..11f7cdab 100644
--- a/lib/common/error_private.c
+++ b/lib/common/error_private.c
@@ -30,14 +30,15 @@ const char* ERR_getErrorString(ERR_enum code)
     case PREFIX(init_missing): return "Context should be init first";
     case PREFIX(memory_allocation): return "Allocation error : not enough memory";
     case PREFIX(stage_wrong): return "Operation not authorized at current processing stage";
-    case PREFIX(dstSize_tooSmall): return "Destination buffer is too small";
-    case PREFIX(srcSize_wrong): return "Src size is incorrect";
     case PREFIX(tableLog_tooLarge): return "tableLog requires too much memory : unsupported";
     case PREFIX(maxSymbolValue_tooLarge): return "Unsupported max Symbol Value : too large";
     case PREFIX(maxSymbolValue_tooSmall): return "Specified maxSymbolValue is too small";
     case PREFIX(dictionary_corrupted): return "Dictionary is corrupted";
     case PREFIX(dictionary_wrong): return "Dictionary mismatch";
     case PREFIX(dictionaryCreation_failed): return "Cannot create Dictionary from provided samples";
+    case PREFIX(dstSize_tooSmall): return "Destination buffer is too small";
+    case PREFIX(srcSize_wrong): return "Src size is incorrect";
+        /* following error codes are not stable and may be removed or changed in a future version */
     case PREFIX(frameIndex_tooLarge): return "Frame index is too large";
     case PREFIX(seekableIO): return "An I/O error occurred when reading/seeking";
     case PREFIX(maxCode):
diff --git a/lib/common/zstd_errors.h b/lib/common/zstd_errors.h
index bde4304c..4bcb7769 100644
--- a/lib/common/zstd_errors.h
+++ b/lib/common/zstd_errors.h
@@ -63,9 +63,10 @@ typedef enum {
   ZSTD_error_memory_allocation = 64,
   ZSTD_error_dstSize_tooSmall = 70,
   ZSTD_error_srcSize_wrong    = 72,
+  /* following error codes are not stable and may be removed or changed in a future version */
   ZSTD_error_frameIndex_tooLarge = 100,
   ZSTD_error_seekableIO          = 102,
-  ZSTD_error_maxCode = 120  /* never EVER use this value directly, it may change in future versions! Use ZSTD_isError() instead */
+  ZSTD_error_maxCode = 120  /* never EVER use this value directly, it can change in future versions! Use ZSTD_isError() instead */
 } ZSTD_ErrorCode;
 
 /*! ZSTD_getErrorCode() :
diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index 0380f6a1..332bf860 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -2407,12 +2407,12 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
     if (input->pos > input->size) {  /* forbidden */
         DEBUGLOG(5, "in: pos: %u   vs size: %u",
                     (U32)input->pos, (U32)input->size);
-        return ERROR(GENERIC);
+        return ERROR(srcSize_wrong);
     }
     if (output->pos > output->size) {  /* forbidden */
         DEBUGLOG(5, "out: pos: %u   vs size: %u",
                     (U32)output->pos, (U32)output->size);
-        return ERROR(GENERIC);
+        return ERROR(dstSize_tooSmall);
     }
     DEBUGLOG(5, "input size : %u", (U32)(input->size - input->pos));