bool loadBlock(std::string &error) {
clearFilters();
position = -1;
//LOG_VERBOSE("seeking to offset %i", (int) iter->block.compressed_file_offset);
reader.seek(iter.block.compressed_file_offset);
strm.avail_in = 0; /* make sure we read new data after lseek */
if (!fill_input_buffer(error)) return false;
if (0 == strm.avail_in) {
error.assign("Unexpected end of file while trying to read block header");
return false;
}
block.version = 0;
block.check = iter.stream.flags->check;
block.header_size = lzma_block_header_size_decode(strm.next_in[0]);
if (block.header_size > strm.avail_in) {
error.assign("Unexpected end of file while trying to read block header");
return false;
}
// Decode the Block Header.
lzma_ret ret = lzma_block_header_decode(&block, NULL, strm.next_in);
if (LZMA_OK != ret) {
errnoLzmaToStr("decoding block header failed", ret, error);
return false;
}
ret = lzma_block_compressed_size(&block, iter.block.unpadded_size);
if (LZMA_OK != ret) {
errnoLzmaToStr("decoding block header failed, invalid compressed size", ret, error);
return false;
}
strm.next_in += block.header_size;
strm.avail_in -= block.header_size;
lzma_end(&strm);
ret = lzma_block_decoder(&strm, &block);
if (LZMA_OK != ret) {
errnoLzmaToStr("couldn't initialize block decoder", ret, error);
return false;
}
position = iter.block.uncompressed_file_offset;
return true;
}
/// \brief Parse the Block Header
///
/// The result is stored into *bhi. The caller takes care of initializing it.
///
/// \return False on success, true on error.
static bool
parse_block_header(file_pair *pair, const lzma_index_iter *iter,
block_header_info *bhi, xz_file_info *xfi)
{
#if IO_BUFFER_SIZE < LZMA_BLOCK_HEADER_SIZE_MAX
# error IO_BUFFER_SIZE < LZMA_BLOCK_HEADER_SIZE_MAX
#endif
// Get the whole Block Header with one read, but don't read past
// the end of the Block (or even its Check field).
const uint32_t size = my_min(iter->block.total_size
- lzma_check_size(iter->stream.flags->check),
LZMA_BLOCK_HEADER_SIZE_MAX);
io_buf buf;
if (io_pread(pair, &buf, size, iter->block.compressed_file_offset))
return true;
// Zero would mean Index Indicator and thus not a valid Block.
if (buf.u8[0] == 0)
goto data_error;
// Initialize the block structure and decode Block Header Size.
lzma_filter filters[LZMA_FILTERS_MAX + 1];
lzma_block block;
block.version = 0;
block.check = iter->stream.flags->check;
block.filters = filters;
block.header_size = lzma_block_header_size_decode(buf.u8[0]);
if (block.header_size > size)
goto data_error;
// Decode the Block Header.
switch (lzma_block_header_decode(&block, NULL, buf.u8)) {
case LZMA_OK:
break;
case LZMA_OPTIONS_ERROR:
message_error("%s: %s", pair->src_name,
message_strm(LZMA_OPTIONS_ERROR));
return true;
case LZMA_DATA_ERROR:
goto data_error;
default:
message_bug();
}
// Check the Block Flags. These must be done before calling
// lzma_block_compressed_size(), because it overwrites
// block.compressed_size.
bhi->flags[0] = block.compressed_size != LZMA_VLI_UNKNOWN
? 'c' : '-';
bhi->flags[1] = block.uncompressed_size != LZMA_VLI_UNKNOWN
? 'u' : '-';
bhi->flags[2] = '\0';
// Collect information if all Blocks have both Compressed Size
// and Uncompressed Size fields. They can be useful e.g. for
// multi-threaded decompression so it can be useful to know it.
xfi->all_have_sizes &= block.compressed_size != LZMA_VLI_UNKNOWN
&& block.uncompressed_size != LZMA_VLI_UNKNOWN;
// Validate or set block.compressed_size.
switch (lzma_block_compressed_size(&block,
iter->block.unpadded_size)) {
case LZMA_OK:
// Validate also block.uncompressed_size if it is present.
// If it isn't present, there's no need to set it since
// we aren't going to actually decompress the Block; if
// we were decompressing, then we should set it so that
// the Block decoder could validate the Uncompressed Size
// that was stored in the Index.
if (block.uncompressed_size == LZMA_VLI_UNKNOWN
|| block.uncompressed_size
== iter->block.uncompressed_size)
break;
// If the above fails, the file is corrupt so
// LZMA_DATA_ERROR is a good error code.
// Fall through
case LZMA_DATA_ERROR:
// Free the memory allocated by lzma_block_header_decode().
for (size_t i = 0; filters[i].id != LZMA_VLI_UNKNOWN; ++i)
free(filters[i].options);
goto data_error;
default:
message_bug();
}
// Copy the known sizes.
bhi->header_size = block.header_size;
bhi->compressed_size = block.compressed_size;
// Calculate the decoder memory usage and update the maximum
// memory usage of this Block.
bhi->memusage = lzma_raw_decoder_memusage(filters);
if (xfi->memusage_max < bhi->memusage)
xfi->memusage_max = bhi->memusage;
// Determine the minimum XZ Utils version that supports this Block.
//
// Currently the only thing that 5.0.0 doesn't support is empty
// LZMA2 Block. This decoder bug was fixed in 5.0.2.
{
size_t i = 0;
while (filters[i + 1].id != LZMA_VLI_UNKNOWN)
++i;
if (filters[i].id == LZMA_FILTER_LZMA2
&& iter->block.uncompressed_size == 0
&& xfi->min_version < 50000022U)
xfi->min_version = 50000022U;
}
// Convert the filter chain to human readable form.
message_filters_to_str(bhi->filter_chain, filters, false);
// Free the memory allocated by lzma_block_header_decode().
for (size_t i = 0; filters[i].id != LZMA_VLI_UNKNOWN; ++i)
free(filters[i].options);
return false;
data_error:
// Show the error message.
message_error("%s: %s", pair->src_name,
message_strm(LZMA_DATA_ERROR));
return true;
}
/// \brief Parse the Block Header
///
/// The result is stored into *bhi. The caller takes care of initializing it.
///
/// \return False on success, true on error.
static bool
parse_block_header(file_pair *pair, const lzma_index_iter *iter,
block_header_info *bhi, xz_file_info *xfi)
{
#if IO_BUFFER_SIZE < LZMA_BLOCK_HEADER_SIZE_MAX
# error IO_BUFFER_SIZE < LZMA_BLOCK_HEADER_SIZE_MAX
#endif
// Get the whole Block Header with one read, but don't read past
// the end of the Block (or even its Check field).
const uint32_t size = my_min(iter->block.total_size
- lzma_check_size(iter->stream.flags->check),
LZMA_BLOCK_HEADER_SIZE_MAX);
io_buf buf;
if (io_pread(pair, &buf, size, iter->block.compressed_file_offset))
return true;
// Zero would mean Index Indicator and thus not a valid Block.
if (buf.u8[0] == 0)
goto data_error;
lzma_block block;
lzma_filter filters[LZMA_FILTERS_MAX + 1];
// Initialize the pointers so that they can be passed to free().
for (size_t i = 0; i < ARRAY_SIZE(filters); ++i)
filters[i].options = NULL;
// Initialize the block structure and decode Block Header Size.
block.version = 0;
block.check = iter->stream.flags->check;
block.filters = filters;
block.header_size = lzma_block_header_size_decode(buf.u8[0]);
if (block.header_size > size)
goto data_error;
// Decode the Block Header.
switch (lzma_block_header_decode(&block, NULL, buf.u8)) {
case LZMA_OK:
break;
case LZMA_OPTIONS_ERROR:
message_error("%s: %s", pair->src_name,
message_strm(LZMA_OPTIONS_ERROR));
return true;
case LZMA_DATA_ERROR:
goto data_error;
default:
message_bug();
}
// Check the Block Flags. These must be done before calling
// lzma_block_compressed_size(), because it overwrites
// block.compressed_size.
bhi->flags[0] = block.compressed_size != LZMA_VLI_UNKNOWN
? 'c' : '-';
bhi->flags[1] = block.uncompressed_size != LZMA_VLI_UNKNOWN
? 'u' : '-';
bhi->flags[2] = '\0';
// Collect information if all Blocks have both Compressed Size
// and Uncompressed Size fields. They can be useful e.g. for
// multi-threaded decompression so it can be useful to know it.
xfi->all_have_sizes &= block.compressed_size != LZMA_VLI_UNKNOWN
&& block.uncompressed_size != LZMA_VLI_UNKNOWN;
// Validate or set block.compressed_size.
switch (lzma_block_compressed_size(&block,
iter->block.unpadded_size)) {
case LZMA_OK:
break;
case LZMA_DATA_ERROR:
goto data_error;
default:
message_bug();
}
// Copy the known sizes.
bhi->header_size = block.header_size;
bhi->compressed_size = block.compressed_size;
// Calculate the decoder memory usage and update the maximum
// memory usage of this Block.
bhi->memusage = lzma_raw_decoder_memusage(filters);
if (xfi->memusage_max < bhi->memusage)
xfi->memusage_max = bhi->memusage;
// Convert the filter chain to human readable form.
message_filters_to_str(bhi->filter_chain, filters, false);
// Free the memory allocated by lzma_block_header_decode().
for (size_t i = 0; filters[i].id != LZMA_VLI_UNKNOWN; ++i)
free(filters[i].options);
return false;
data_error:
// Show the error message.
message_error("%s: %s", pair->src_name,
message_strm(LZMA_DATA_ERROR));
// Free the memory allocated by lzma_block_header_decode().
// This is truly needed only if we get here after a succcessful
// call to lzma_block_header_decode() but it doesn't hurt to
// always do it.
for (size_t i = 0; filters[i].id != LZMA_VLI_UNKNOWN; ++i)
free(filters[i].options);
return true;
}