filter_buffer_decoder.c

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//
//
//  Author:     Lasse Collin
//
//  This file has been put into the public domain.
//  You can do whatever you want with this file.
//
 
#include "filter_decoder.h"
 
 
extern LZMA_API(lzma_ret)
lzma_raw_buffer_decode(
        const lzma_filter *filters, 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)
{
    // Validate what isn't validated later in filter_common.c.
    if (in == NULL || in_pos == NULL || *in_pos > in_size || out == NULL
            || out_pos == NULL || *out_pos > out_size)
        return LZMA_PROG_ERROR;
 
    // Initialize the decoer.
    lzma_next_coder next = LZMA_NEXT_CODER_INIT;
    return_if_error(lzma_raw_decoder_init(&next, allocator, filters));
 
    // Store the positions so that we can restore them if something
    // goes wrong.
    const size_t in_start = *in_pos;
    const size_t out_start = *out_pos;
 
    // Do the actual decoding and free decoder's memory.
    lzma_ret ret = next.code(next.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 (*in_pos != in_size) {
                // Since input wasn't consumed completely,
                // the output buffer became full and is
                // too small.
                ret = LZMA_BUF_ERROR;
 
            } else if (*out_pos != out_size) {
                // Since output didn't became full, the input
                // has to be truncated.
                ret = LZMA_DATA_ERROR;
 
            } else {
                // All the input was consumed and output
                // buffer is full. Now we don't immediately
                // know the reason for the error. Try
                // decoding one more byte. If it succeeds,
                // then the output buffer was too small. If
                // we cannot get a new output byte, the input
                // is truncated.
                uint8_t tmp[1];
                size_t tmp_pos = 0;
                (void)next.code(next.coder, allocator,
                        in, in_pos, in_size,
                        tmp, &tmp_pos, 1, LZMA_FINISH);
 
                if (tmp_pos == 1)
                    ret = LZMA_BUF_ERROR;
                else
                    ret = LZMA_DATA_ERROR;
            }
        }
 
        // Restore the positions.
        *in_pos = in_start;
        *out_pos = out_start;
    }
 
    lzma_next_end(&next, allocator);
 
    return ret;
}