source: vbox/trunk/src/libs/liblzma-5.8.1/common/block_buffer_decoder.c@ 108911

// SPDX-License-Identifier: 0BSD

///////////////////////////////////////////////////////////////////////////////
//
/// \file       block_buffer_decoder.c
/// \brief      Single-call .xz Block decoder
//
//  Author:     Lasse Collin
//
///////////////////////////////////////////////////////////////////////////////

#include "block_decoder.h"


extern LZMA_API(lzma_ret)
lzma_block_buffer_decode(lzma_block *block, const 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;
                }
        }

        // 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;
}