xz/src/liblzma/common/block_buffer_decoder.c

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///////////////////////////////////////////////////////////////////////////////
//
/// \file block_buffer_decoder.c
/// \brief Single-call .xz Block decoder
//
// Author: Lasse Collin
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//
// This file has been put into the public domain.
// You can do whatever you want with this file.
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//
///////////////////////////////////////////////////////////////////////////////
#include "block_decoder.h"
extern LZMA_API(lzma_ret)
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lzma_block_buffer_decode(lzma_block *block, lzma_allocator *allocator,
const uint8_t *in, size_t *in_pos, size_t in_size,
uint8_t *out, size_t *out_pos, size_t out_size)
{
if (in_pos == NULL || (in == NULL && *in_pos != in_size)
|| *in_pos > in_size || out_pos == NULL
|| (out == NULL && *out_pos != out_size)
|| *out_pos > out_size)
return LZMA_PROG_ERROR;
// Initialize the Block decoder.
lzma_next_coder block_decoder = LZMA_NEXT_CODER_INIT;
lzma_ret ret = lzma_block_decoder_init(
&block_decoder, allocator, block);
if (ret == LZMA_OK) {
// Save the positions so that we can restore them in case
// an error occurs.
const size_t in_start = *in_pos;
const size_t out_start = *out_pos;
// Do the actual decoding.
ret = block_decoder.code(block_decoder.coder, allocator,
in, in_pos, in_size, out, out_pos, out_size,
LZMA_FINISH);
if (ret == LZMA_STREAM_END) {
ret = LZMA_OK;
} else {
if (ret == LZMA_OK) {
// Either the input was truncated or the
// output buffer was too small.
assert(*in_pos == in_size
|| *out_pos == out_size);
// If all the input was consumed, then the
// input is truncated, even if the output
// buffer is also full. This is because
// processing the last byte of the Block
// never produces output.
//
// NOTE: This assumption may break when new
// filters are added, if the end marker of
// the filter doesn't consume at least one
// complete byte.
if (*in_pos == in_size)
ret = LZMA_DATA_ERROR;
else
ret = LZMA_BUF_ERROR;
}
// Restore the positions.
*in_pos = in_start;
*out_pos = out_start;
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}
}
// Free the decoder memory. This needs to be done even if
// initialization fails, because the internal API doesn't
// require the initialization function to free its memory on error.
lzma_next_end(&block_decoder, allocator);
return ret;
}