///////////////////////////////////////////////////////////////////////////////
//
/// \file stream_decoder.c
/// \brief Decodes .lzma Streams
//
// 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.
//
///////////////////////////////////////////////////////////////////////////////
#include "stream_common.h"
#include "check.h"
#include "stream_flags_decoder.h"
#include "block_decoder.h"
#include "metadata_decoder.h"
struct lzma_coder_s {
enum {
SEQ_STREAM_HEADER_CODE,
SEQ_BLOCK_HEADER_INIT,
SEQ_BLOCK_HEADER_CODE,
SEQ_METADATA_CODE,
SEQ_DATA_CODE,
SEQ_STREAM_TAIL_INIT,
SEQ_STREAM_TAIL_CODE,
} sequence;
/// Position in variable-length integers and in some other things.
size_t pos;
/// Block or Metadata decoder. This takes little memory and the same
/// data structure can be used to decode every Block Header, so it's
/// a good idea to have a separate lzma_next_coder structure for it.
lzma_next_coder block_decoder;
/// Block Header decoder; this is separate
lzma_next_coder block_header_decoder;
lzma_options_block block_options;
/// Information about the sizes of the Blocks
lzma_info *info;
/// Current Block in *info
lzma_info_iter iter;
/// Number of bytes not yet processed from Data Blocks in the Stream.
/// This can be LZMA_VLI_VALUE_UNKNOWN. If it is known, it is
/// decremented while decoding and verified to match the reality.
lzma_vli total_left;
/// Like uncompressed_left above but for uncompressed data from
/// Data Blocks.
lzma_vli uncompressed_left;
/// Stream Flags from Stream Header
lzma_stream_flags header_flags;
/// Stream Flags from Stream tail
lzma_stream_flags tail_flags;
/// Decoder for Stream Header and Stream tail. This takes very
/// little memory and the same data structure can be used for
/// both Header and tail, so it's a good idea to have a separate
/// lzma_next_coder structure for it.
lzma_next_coder flags_decoder;
/// Temporary destination for the decoded Metadata.
lzma_metadata metadata;
/// Pointer to application-supplied pointer where to store the list
/// of Extra Records from the Header Metadata Block.
lzma_extra **header_extra;
/// Same as above but Footer Metadata Block
lzma_extra **footer_extra;
};
static lzma_ret
metadata_init(lzma_coder *coder, lzma_allocator *allocator)
{
assert(coder->metadata.index == NULL);
assert(coder->metadata.extra == NULL);
// Single-Block Streams don't have Metadata Blocks.
if (!coder->header_flags.is_multi)
return LZMA_DATA_ERROR;
coder->block_options.total_limit = LZMA_VLI_VALUE_UNKNOWN;
// Limit the Uncompressed Size of a Metadata Block. This is to
// prevent security issues where input file would have very huge
// Metadata.
//
// FIXME: Hardcoded constant is ugly. Maybe we should provide
// some way to specify this from the application.
coder->block_options.uncompressed_limit = LZMA_VLI_C(1) << 23;
lzma_info_size size_type;
bool want_extra;
// If we haven't decoded any Data Blocks yet, this is Header
// Metadata Block.
if (lzma_info_index_count_get(coder->info) == 0) {
coder->block_options.has_backward_size = false;
coder->block_options.handle_padding = true;
size_type = LZMA_INFO_HEADER_METADATA;
want_extra = coder->header_extra != NULL;
} else {
if (lzma_info_index_finish(coder->info))
return LZMA_DATA_ERROR;
coder->block_options.has_backward_size = true;
coder->block_options.handle_padding = false;
size_type = LZMA_INFO_FOOTER_METADATA;
want_extra = coder->footer_extra != NULL;
}
coder->block_options.has_uncompressed_size_in_footer = false;
coder->block_options.total_size = lzma_info_size_get(
coder->info, size_type);
coder->sequence = SEQ_METADATA_CODE;
return lzma_metadata_decoder_init(&coder->block_decoder, allocator,
&coder->block_options, &coder->metadata, want_extra);
}
static lzma_ret
data_init(lzma_coder *coder, lzma_allocator *allocator)
{
return_if_error(lzma_info_iter_next(&coder->iter, allocator));
return_if_error(lzma_info_iter_set(
&coder->iter, LZMA_VLI_VALUE_UNKNOWN,
coder->block_options.uncompressed_size));
coder->block_options.total_size = coder->iter.total_size;
coder->block_options.uncompressed_size = coder->iter.uncompressed_size;
coder->block_options.total_limit = coder->total_left;
coder->block_options.uncompressed_limit = coder->uncompressed_left;
if (coder->header_flags.is_multi) {
coder->block_options.has_uncompressed_size_in_footer = false;
coder->block_options.has_backward_size = false;
coder->block_options.handle_padding = true;
} else {
coder->block_options.has_uncompressed_size_in_footer
= coder->iter.uncompressed_size
== LZMA_VLI_VALUE_UNKNOWN;
coder->block_options.has_backward_size = true;
coder->block_options.handle_padding = false;
}
coder->sequence = SEQ_DATA_CODE;
return lzma_block_decoder_init(&coder->block_decoder, allocator,
&coder->block_options);
}
static lzma_ret
stream_decode(lzma_coder *coder, lzma_allocator *allocator,
const uint8_t *restrict in, size_t *restrict in_pos,
size_t in_size, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size, lzma_action action)
{
while (*out_pos < out_size && (*in_pos < in_size
|| coder->sequence == SEQ_DATA_CODE))
switch (coder->sequence) {
case SEQ_STREAM_HEADER_CODE: {
const lzma_ret ret = coder->flags_decoder.code(
coder->flags_decoder.coder,
allocator, in, in_pos, in_size,
NULL, NULL, 0, LZMA_RUN);
if (ret != LZMA_STREAM_END)
return ret;
coder->sequence = SEQ_BLOCK_HEADER_INIT;
// Detect if the Check type is supported and give appropriate
// warning if it isn't. We don't warn every time a new Block
// is started.
lzma_check tmp;
if (lzma_check_init(&tmp, coder->header_flags.check))
return LZMA_UNSUPPORTED_CHECK;
break;
}
case SEQ_BLOCK_HEADER_INIT: {
coder->block_options.check = coder->header_flags.check;
coder->block_options.has_crc32 = coder->header_flags.has_crc32;
return_if_error(lzma_block_header_decoder_init(
&coder->block_header_decoder, allocator,
&coder->block_options));
coder->sequence = SEQ_BLOCK_HEADER_CODE;
}
// Fall through
case SEQ_BLOCK_HEADER_CODE: {
lzma_ret ret = coder->block_header_decoder.code(
coder->block_header_decoder.coder,
allocator, in, in_pos, in_size,
NULL, NULL, 0, LZMA_RUN);
if (ret != LZMA_STREAM_END)
return ret;
if (coder->block_options.is_metadata)
ret = metadata_init(coder, allocator);
else
ret = data_init(coder, allocator);
if (ret != LZMA_OK)
return ret;
break;
}
case SEQ_METADATA_CODE: {
lzma_ret ret = coder->block_decoder.code(
coder->block_decoder.coder, allocator,
in, in_pos, in_size, NULL, NULL, 0, LZMA_RUN);
if (ret != LZMA_STREAM_END)
return ret;
const bool is_header_metadata = lzma_info_index_count_get(
coder->info) == 0;
if (is_header_metadata) {
if (coder->header_extra != NULL) {
*coder->header_extra = coder->metadata.extra;
coder->metadata.extra = NULL;
}
if (lzma_info_size_set(coder->info,
LZMA_INFO_HEADER_METADATA,
coder->block_options.total_size)
!= LZMA_OK)
return LZMA_PROG_ERROR;
coder->sequence = SEQ_BLOCK_HEADER_INIT;
} else {
if (coder->footer_extra != NULL) {
*coder->footer_extra = coder->metadata.extra;
coder->metadata.extra = NULL;
}
coder->sequence = SEQ_STREAM_TAIL_INIT;
}
assert(coder->metadata.extra == NULL);
ret = lzma_info_metadata_set(coder->info, allocator,
&coder->metadata, is_header_metadata, true);
if (ret != LZMA_OK)
return ret;
// Intialize coder->total_size and coder->uncompressed_size
// from Header Metadata.
if (is_header_metadata) {
coder->total_left = lzma_info_size_get(
coder->info, LZMA_INFO_TOTAL);
coder->uncompressed_left = lzma_info_size_get(
coder->info, LZMA_INFO_UNCOMPRESSED);
}
break;
}
case SEQ_DATA_CODE: {
lzma_ret ret = coder->block_decoder.code(
coder->block_decoder.coder, allocator,
in, in_pos, in_size, out, out_pos, out_size,
action);
if (ret != LZMA_STREAM_END)
return ret;
ret = lzma_info_iter_set(&coder->iter,
coder->block_options.total_size,
coder->block_options.uncompressed_size);
if (ret != LZMA_OK)
return ret;
// These won't overflow since lzma_info_iter_set() succeeded.
if (coder->total_left != LZMA_VLI_VALUE_UNKNOWN)
coder->total_left -= coder->block_options.total_size;
if (coder->uncompressed_left != LZMA_VLI_VALUE_UNKNOWN)
coder->uncompressed_left -= coder->block_options
.uncompressed_size;
if (!coder->header_flags.is_multi) {
ret = lzma_info_index_finish(coder->info);
if (ret != LZMA_OK)
return ret;
coder->sequence = SEQ_STREAM_TAIL_INIT;
break;
}
coder->sequence = SEQ_BLOCK_HEADER_INIT;
break;
}
case SEQ_STREAM_TAIL_INIT: {
lzma_ret ret = lzma_info_index_finish(coder->info);
if (ret != LZMA_OK)
return ret;
ret = lzma_stream_tail_decoder_init(&coder->flags_decoder,
allocator, &coder->tail_flags);
if (ret != LZMA_OK)
return ret;
coder->sequence = SEQ_STREAM_TAIL_CODE;
}
// Fall through
case SEQ_STREAM_TAIL_CODE: {
const lzma_ret ret = coder->flags_decoder.code(
coder->flags_decoder.coder, allocator,
in, in_pos, in_size, NULL, NULL, 0, LZMA_RUN);
if (ret != LZMA_STREAM_END)
return ret;
if (!lzma_stream_flags_is_equal(
coder->header_flags, coder->tail_flags))
return LZMA_DATA_ERROR;
return LZMA_STREAM_END;
}
default:
return LZMA_PROG_ERROR;
}
return LZMA_OK;
}
static void
stream_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
{
lzma_next_coder_end(&coder->block_decoder, allocator);
lzma_next_coder_end(&coder->block_header_decoder, allocator);
lzma_next_coder_end(&coder->flags_decoder, allocator);
lzma_info_free(coder->info, allocator);
lzma_index_free(coder->metadata.index, allocator);
lzma_extra_free(coder->metadata.extra, allocator);
lzma_free(coder, allocator);
return;
}
static lzma_ret
stream_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
lzma_extra **header, lzma_extra **footer)
{
if (next->coder == NULL) {
next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
if (next->coder == NULL)
return LZMA_MEM_ERROR;
next->code = &stream_decode;
next->end = &stream_decoder_end;
next->coder->block_decoder = LZMA_NEXT_CODER_INIT;
next->coder->block_header_decoder = LZMA_NEXT_CODER_INIT;
next->coder->info = NULL;
next->coder->flags_decoder = LZMA_NEXT_CODER_INIT;
next->coder->metadata.index = NULL;
next->coder->metadata.extra = NULL;
} else {
lzma_index_free(next->coder->metadata.index, allocator);
next->coder->metadata.index = NULL;
lzma_extra_free(next->coder->metadata.extra, allocator);
next->coder->metadata.extra = NULL;
}
next->coder->info = lzma_info_init(next->coder->info, allocator);
if (next->coder->info == NULL)
return LZMA_MEM_ERROR;
lzma_info_iter_begin(next->coder->info, &next->coder->iter);
// Initialize Stream Header decoder.
return_if_error(lzma_stream_header_decoder_init(
&next->coder->flags_decoder, allocator,
&next->coder->header_flags));
// Reset the *foo_extra pointers to NULL. This way the caller knows
// if there were no Extra Records. (We don't support appending
// Records to Extra list.)
if (header != NULL)
*header = NULL;
if (footer != NULL)
*footer = NULL;
// Reset some variables.
next->coder->sequence = SEQ_STREAM_HEADER_CODE;
next->coder->pos = 0;
next->coder->uncompressed_left = LZMA_VLI_VALUE_UNKNOWN;
next->coder->total_left = LZMA_VLI_VALUE_UNKNOWN;
next->coder->header_extra = header;
next->coder->footer_extra = footer;
return LZMA_OK;
}
extern lzma_ret
lzma_stream_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
lzma_extra **header, lzma_extra **footer)
{
lzma_next_coder_init(
stream_decoder_init, next, allocator, header, footer);
}
extern LZMA_API lzma_ret
lzma_stream_decoder(lzma_stream *strm,
lzma_extra **header, lzma_extra **footer)
{
lzma_next_strm_init(strm, stream_decoder_init, header, footer);
strm->internal->supported_actions[LZMA_RUN] = true;
strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
return LZMA_OK;
}
