From 2ba01bfa755e47ff6af84a978e3c8d63d7d2775e Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Wed, 10 Sep 2008 00:27:02 +0300 Subject: [PATCH] Cleaned up Block encoder and moved the no longer shared code from block_private.h to block_decoder.c. Now the Block encoder doesn't need compressed_size and uncompressed_size from lzma_block structure to be initialized. --- src/liblzma/api/lzma/block.h | 3 - src/liblzma/common/Makefile.am | 1 - src/liblzma/common/block_decoder.c | 23 +++++++- src/liblzma/common/block_encoder.c | 92 ++++++++++++++---------------- src/liblzma/common/block_private.h | 47 --------------- 5 files changed, 66 insertions(+), 100 deletions(-) delete mode 100644 src/liblzma/common/block_private.h diff --git a/src/liblzma/api/lzma/block.h b/src/liblzma/api/lzma/block.h index 4504581..60ea97f 100644 --- a/src/liblzma/api/lzma/block.h +++ b/src/liblzma/api/lzma/block.h @@ -38,7 +38,6 @@ typedef struct { * Read by: * - lzma_block_header_encode() * - lzma_block_header_decode() - * - lzma_block_encoder() * - lzma_block_decoder() * * Written by: @@ -74,7 +73,6 @@ typedef struct { * Read by: * - lzma_block_header_size() * - lzma_block_header_encode() - * - lzma_block_encoder() * - lzma_block_decoder() * * Written by: @@ -103,7 +101,6 @@ typedef struct { * Read by: * - lzma_block_header_size() * - lzma_block_header_encode() - * - lzma_block_encoder() * - lzma_block_decoder() * * Written by: diff --git a/src/liblzma/common/Makefile.am b/src/liblzma/common/Makefile.am index 3ec2e27..ca38afc 100644 --- a/src/liblzma/common/Makefile.am +++ b/src/liblzma/common/Makefile.am @@ -28,7 +28,6 @@ libcommon_la_SOURCES = \ common.h \ bsr.h \ block_util.c \ - block_private.h \ filter_common.c \ filter_common.h \ index.c \ diff --git a/src/liblzma/common/block_decoder.c b/src/liblzma/common/block_decoder.c index eab25a8..9eb3365 100644 --- a/src/liblzma/common/block_decoder.c +++ b/src/liblzma/common/block_decoder.c @@ -18,7 +18,6 @@ /////////////////////////////////////////////////////////////////////////////// #include "block_decoder.h" -#include "block_private.h" #include "filter_decoder.h" #include "check.h" @@ -56,6 +55,28 @@ struct lzma_coder_s { }; +static inline bool +update_size(lzma_vli *size, lzma_vli add, lzma_vli limit) +{ + if (limit > LZMA_VLI_VALUE_MAX) + limit = LZMA_VLI_VALUE_MAX; + + if (limit < *size || limit - *size < add) + return true; + + *size += add; + + return false; +} + + +static inline bool +is_size_valid(lzma_vli size, lzma_vli reference) +{ + return reference == LZMA_VLI_VALUE_UNKNOWN || reference == size; +} + + static lzma_ret block_decode(lzma_coder *coder, lzma_allocator *allocator, const uint8_t *restrict in, size_t *restrict in_pos, diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c index 5aa3626..ee75033 100644 --- a/src/liblzma/common/block_encoder.c +++ b/src/liblzma/common/block_encoder.c @@ -18,11 +18,25 @@ /////////////////////////////////////////////////////////////////////////////// #include "block_encoder.h" -#include "block_private.h" #include "filter_encoder.h" #include "check.h" +/// The maximum size of a single Block is limited by the maximum size of +/// a Stream, which is 2^63 - 1 bytes (i.e. LZMA_VLI_VALUE_MAX). We could +/// take into account the headers etc. to determine the exact maximum size +/// of the Compressed Data field, but the complexity would give us nothing +/// useful. Instead, limit the size of Compressed Data so that even with +/// biggest possible Block Header and Check fields the total size of the +/// Block stays as valid VLI. This way we don't produce incorrect output +/// if someone will really try creating a Block of 8 EiB. +/// +/// ~LZMA_VLI_C(3) is to guarantee that if we need padding at the end of +/// the Compressed Data field, it will still stay in the proper limit. +#define COMPRESSED_SIZE_MAX ((LZMA_VLI_VALUE_MAX - LZMA_BLOCK_HEADER_SIZE_MAX \ + - LZMA_CHECK_SIZE_MAX) & ~LZMA_VLI_C(3)) + + struct lzma_coder_s { /// The filters in the chain; initialized with lzma_raw_decoder_init(). lzma_next_coder next; @@ -59,26 +73,9 @@ block_encode(lzma_coder *coder, lzma_allocator *allocator, size_t *restrict out_pos, size_t out_size, lzma_action action) { // Check that our amount of input stays in proper limits. - if (coder->options->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN) { - if (action == LZMA_FINISH) { - if (coder->options->uncompressed_size - - coder->uncompressed_size - != (lzma_vli)(in_size - *in_pos)) - return LZMA_PROG_ERROR; - } else { - if (coder->options->uncompressed_size - - coder->uncompressed_size - < (lzma_vli)(in_size - *in_pos)) - return LZMA_PROG_ERROR; - } - } else if (LZMA_VLI_VALUE_MAX - coder->uncompressed_size - < (lzma_vli)(in_size - *in_pos)) { + if (LZMA_VLI_VALUE_MAX - coder->uncompressed_size < in_size - *in_pos) return LZMA_PROG_ERROR; - } - // Main loop - while (*out_pos < out_size - && (*in_pos < in_size || action != LZMA_RUN)) switch (coder->sequence) { case SEQ_CODE: { const size_t in_start = *in_pos; @@ -91,12 +88,11 @@ block_encode(lzma_coder *coder, lzma_allocator *allocator, const size_t in_used = *in_pos - in_start; const size_t out_used = *out_pos - out_start; - // FIXME We must also check that Total Size doesn't get - // too big. - if (update_size(&coder->compressed_size, out_used, - coder->options->compressed_size)) + if (COMPRESSED_SIZE_MAX - coder->compressed_size < out_used) return LZMA_DATA_ERROR; + coder->compressed_size += out_used; + // No need to check for overflow because we have already // checked it at the beginning of this function. coder->uncompressed_size += in_used; @@ -108,31 +104,28 @@ block_encode(lzma_coder *coder, lzma_allocator *allocator, return ret; assert(*in_pos == in_size); + assert(action == LZMA_FINISH); + coder->sequence = SEQ_PADDING; - break; } + // Fall through + case SEQ_PADDING: // Pad Compressed Data to a multiple of four bytes. - if (coder->compressed_size & 3) { + while (coder->compressed_size & 3) { + if (*out_pos >= out_size) + return LZMA_OK; + out[*out_pos] = 0x00; ++*out_pos; - if (update_size(&coder->compressed_size, 1, - coder->options->compressed_size)) - return LZMA_DATA_ERROR; - - break; + // No need to use check for overflow here since we + // have already checked in SEQ_CODE that Compressed + // Size will stay in proper limits. + ++coder->compressed_size; } - // Compressed and Uncompressed Sizes are now at their final - // values. Verify that they match the values given to us. - if (!is_size_valid(coder->compressed_size, - coder->options->compressed_size) - || !is_size_valid(coder->uncompressed_size, - coder->options->uncompressed_size)) - return LZMA_DATA_ERROR; - // Copy the values into coder->options. The caller // may use this information to construct Index. coder->options->compressed_size = coder->compressed_size; @@ -146,21 +139,24 @@ block_encode(lzma_coder *coder, lzma_allocator *allocator, // Fall through - case SEQ_CHECK: - out[*out_pos] = coder->check.buffer.u8[coder->check_pos]; - ++*out_pos; + case SEQ_CHECK: { + const uint32_t check_size + = lzma_check_size(coder->options->check); - if (++coder->check_pos - == lzma_check_size(coder->options->check)) - return LZMA_STREAM_END; + while (*out_pos < out_size) { + out[*out_pos] = coder->check.buffer.u8[ + coder->check_pos]; + ++*out_pos; - break; + if (++coder->check_pos == check_size) + return LZMA_STREAM_END; + } - default: - return LZMA_PROG_ERROR; + return LZMA_OK; + } } - return LZMA_OK; + return LZMA_PROG_ERROR; } diff --git a/src/liblzma/common/block_private.h b/src/liblzma/common/block_private.h deleted file mode 100644 index 235e96b..0000000 --- a/src/liblzma/common/block_private.h +++ /dev/null @@ -1,47 +0,0 @@ -/////////////////////////////////////////////////////////////////////////////// -// -/// \file block_private.h -/// \brief Common stuff for Block encoder and decoder -// -// Copyright (C) 2007 Lasse Collin -// -// This library is free software; you can redistribute it and/or -// modify it under the terms of the GNU Lesser General Public -// License as published by the Free Software Foundation; either -// version 2.1 of the License, or (at your option) any later version. -// -// This library is distributed in the hope that it will be useful, -// but WITHOUT ANY WARRANTY; without even the implied warranty of -// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -// Lesser General Public License for more details. -// -/////////////////////////////////////////////////////////////////////////////// - -#ifndef LZMA_BLOCK_COMMON_H -#define LZMA_BLOCK_COMMON_H - -#include "common.h" - - -static inline bool -update_size(lzma_vli *size, lzma_vli add, lzma_vli limit) -{ - if (limit > LZMA_VLI_VALUE_MAX) - limit = LZMA_VLI_VALUE_MAX; - - if (limit < *size || limit - *size < add) - return true; - - *size += add; - - return false; -} - - -static inline bool -is_size_valid(lzma_vli size, lzma_vli reference) -{ - return reference == LZMA_VLI_VALUE_UNKNOWN || reference == size; -} - -#endif