///////////////////////////////////////////////////////////////////////////////
//
/// \file block_decoder.c
/// \brief Decodes .lzma Blocks
//
// 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 "block_decoder.h"
#include "block_private.h"
#include "raw_decoder.h"
#include "check.h"
struct lzma_coder_s {
enum {
SEQ_CODE,
SEQ_CHECK,
SEQ_UNCOMPRESSED_SIZE,
SEQ_BACKWARD_SIZE,
SEQ_PADDING,
SEQ_END,
} sequence;
/// The filters in the chain; initialized with lzma_raw_decoder_init().
lzma_next_coder next;
/// Decoding options; we also write Total Size, Compressed Size, and
/// Uncompressed Size back to this structure when the encoding has
/// been finished.
lzma_options_block *options;
/// Position in variable-length integers (and in some other places).
size_t pos;
/// Check of the uncompressed data
lzma_check check;
/// Total Size calculated while encoding
lzma_vli total_size;
/// Compressed Size calculated while encoding
lzma_vli compressed_size;
/// Uncompressed Size calculated while encoding
lzma_vli uncompressed_size;
/// Maximum allowed total_size
lzma_vli total_limit;
/// Maximum allowed uncompressed_size
lzma_vli uncompressed_limit;
/// Temporary location for the Uncompressed Size and Backward Size
/// fields in Block Footer.
lzma_vli tmp;
/// Size of the Backward Size field - This is needed so that we
/// can verify the Backward Size and still keep updating total_size.
size_t size_of_backward_size;
};
static lzma_ret
update_sequence(lzma_coder *coder)
{
switch (coder->sequence) {
case SEQ_CODE:
if (coder->options->check != LZMA_CHECK_NONE) {
lzma_check_finish(&coder->check,
coder->options->check);
coder->sequence = SEQ_CHECK;
break;
}
// Fall through
case SEQ_CHECK:
if (coder->options->has_uncompressed_size_in_footer) {
coder->sequence = SEQ_UNCOMPRESSED_SIZE;
break;
}
// Fall through
case SEQ_UNCOMPRESSED_SIZE:
if (coder->options->has_backward_size) {
coder->sequence = SEQ_BACKWARD_SIZE;
break;
}
// Fall through
case SEQ_BACKWARD_SIZE:
if (coder->options->handle_padding) {
coder->sequence = SEQ_PADDING;
break;
}
case SEQ_PADDING:
if (!is_size_valid(coder->total_size,
coder->options->total_size)
|| !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->total_size = coder->total_size;
coder->options->compressed_size = coder->compressed_size;
coder->options->uncompressed_size = coder->uncompressed_size;
return LZMA_STREAM_END;
default:
assert(0);
return LZMA_PROG_ERROR;
}
return LZMA_OK;
}
static lzma_ret
block_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)
{
// Special case when the Block has only Block Header.
if (coder->sequence == SEQ_END)
return LZMA_STREAM_END;
// FIXME: Termination condition should work but could be cleaner.
while (*out_pos < out_size && (*in_pos < in_size
|| coder->sequence == SEQ_CODE))
switch (coder->sequence) {
case SEQ_CODE: {
const size_t in_start = *in_pos;
const size_t out_start = *out_pos;
lzma_ret ret = coder->next.code(coder->next.coder,
allocator, in, in_pos, in_size,
out, out_pos, out_size, action);
const size_t in_used = *in_pos - in_start;
const size_t out_used = *out_pos - out_start;
if (update_size(&coder->total_size, in_used,
coder->total_limit)
|| update_size(&coder->compressed_size,
in_used,
coder->options->compressed_size)
|| update_size(&coder->uncompressed_size,
out_used, coder->uncompressed_limit))
return LZMA_DATA_ERROR;
lzma_check_update(&coder->check, coder->options->check,
out + out_start, out_used);
if (ret != LZMA_STREAM_END)
return ret;
ret = update_sequence(coder);
if (ret != LZMA_OK)
return ret;
break;
}
case SEQ_CHECK:
switch (coder->options->check) {
case LZMA_CHECK_CRC32:
if (((coder->check.crc32 >> (coder->pos * 8))
& 0xFF) != in[*in_pos])
return LZMA_DATA_ERROR;
break;
case LZMA_CHECK_CRC64:
if (((coder->check.crc64 >> (coder->pos * 8))
& 0xFF) != in[*in_pos])
return LZMA_DATA_ERROR;
break;
case LZMA_CHECK_SHA256:
if (coder->check.sha256.buffer[coder->pos]
!= in[*in_pos])
return LZMA_DATA_ERROR;
break;
default:
assert(coder->options->check != LZMA_CHECK_NONE);
assert(coder->options->check <= LZMA_CHECK_ID_MAX);
break;
}
if (update_size(&coder->total_size, 1, coder->total_limit))
return LZMA_DATA_ERROR;
++*in_pos;
if (++coder->pos == lzma_check_sizes[coder->options->check]) {
const lzma_ret ret = update_sequence(coder);
if (ret != LZMA_OK)
return ret;
coder->pos = 0;
}
break;
case SEQ_UNCOMPRESSED_SIZE: {
const size_t in_start = *in_pos;
lzma_ret ret = lzma_vli_decode(&coder->tmp,
&coder->pos, in, in_pos, in_size);
if (update_size(&coder->total_size, *in_pos - in_start,
coder->total_limit))
return LZMA_DATA_ERROR;
if (ret != LZMA_STREAM_END)
return ret;
if (coder->tmp != coder->uncompressed_size)
return LZMA_DATA_ERROR;
coder->pos = 0;
coder->tmp = 0;
ret = update_sequence(coder);
if (ret != LZMA_OK)
return ret;
break;
}
case SEQ_BACKWARD_SIZE: {
const size_t in_start = *in_pos;
lzma_ret ret = lzma_vli_decode(&coder->tmp,
&coder->pos, in, in_pos, in_size);
const size_t in_used = *in_pos - in_start;
if (update_size(&coder->total_size, in_used,
coder->total_limit))
return LZMA_DATA_ERROR;
coder->size_of_backward_size += in_used;
if (ret != LZMA_STREAM_END)
return ret;
if (coder->tmp != coder->total_size
- coder->size_of_backward_size)
return LZMA_DATA_ERROR;
ret = update_sequence(coder);
if (ret != LZMA_OK)
return ret;
break;
}
case SEQ_PADDING:
if (in[*in_pos] == 0x00) {
if (update_size(&coder->total_size, 1,
coder->total_limit))
return LZMA_DATA_ERROR;
++*in_pos;
break;
}
return update_sequence(coder);
default:
return LZMA_PROG_ERROR;
}
return LZMA_OK;
}
static void
block_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
{
lzma_next_coder_end(&coder->next, allocator);
lzma_free(coder, allocator);
return;
}
extern lzma_ret
lzma_block_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
lzma_options_block *options)
{
// This is pretty similar to lzma_block_encoder_init().
// See comments there.
if (next->coder == NULL) {
next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
if (next->coder == NULL)
return LZMA_MEM_ERROR;
next->code = &block_decode;
next->end = &block_decoder_end;
next->coder->next = LZMA_NEXT_CODER_INIT;
}
if (!lzma_vli_is_valid(options->total_size)
|| !lzma_vli_is_valid(options->compressed_size)
|| !lzma_vli_is_valid(options->uncompressed_size)
|| !lzma_vli_is_valid(options->total_size)
|| !lzma_vli_is_valid(options->total_limit)
|| !lzma_vli_is_valid(options->uncompressed_limit)
|| (options->uncompressed_size
!= LZMA_VLI_VALUE_UNKNOWN
&& options->uncompressed_size
> options->uncompressed_limit)
|| (options->total_size != LZMA_VLI_VALUE_UNKNOWN
&& options->total_size
> options->total_limit)
|| (!options->has_eopm && options->uncompressed_size
== LZMA_VLI_VALUE_UNKNOWN)
|| options->header_size > options->total_size
|| (options->handle_padding
&& (options->has_uncompressed_size_in_footer
|| options->has_backward_size)))
return LZMA_PROG_ERROR;
return_if_error(lzma_check_init(&next->coder->check, options->check));
next->coder->sequence = SEQ_CODE;
next->coder->options = options;
next->coder->pos = 0;
next->coder->total_size = options->header_size;
next->coder->compressed_size = 0;
next->coder->uncompressed_size = 0;
next->coder->total_limit
= MIN(options->total_size, options->total_limit);
next->coder->uncompressed_limit = MIN(options->uncompressed_size,
options->uncompressed_limit);
next->coder->tmp = 0;
next->coder->size_of_backward_size = 0;
if (!options->has_eopm && options->uncompressed_size == 0) {
// The Compressed Data field is empty, thus we skip SEQ_CODE
// phase completely.
const lzma_ret ret = update_sequence(next->coder);
if (ret != LZMA_OK && ret != LZMA_STREAM_END)
return LZMA_PROG_ERROR;
}
return lzma_raw_decoder_init(&next->coder->next, allocator,
options->filters, options->has_eopm
? LZMA_VLI_VALUE_UNKNOWN
: options->uncompressed_size,
true);
}
extern LZMA_API lzma_ret
lzma_block_decoder(lzma_stream *strm, lzma_options_block *options)
{
lzma_next_strm_init(strm, lzma_block_decoder_init, options);
strm->internal->supported_actions[LZMA_RUN] = true;
strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
return LZMA_OK;
}
