contrib/xz/src/liblzma/common/filter_buffer_decoder.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       filter_buffer_decoder.c
   4 /// \brief      Single-call raw decoding
   5 //
   6 //  Author:     Lasse Collin
   7 //
   8 //  This file has been put into the public domain.
   9 //  You can do whatever you want with this file.
  10 //
  11 ///////////////////////////////////////////////////////////////////////////////
  12
  13 #include "filter_decoder.h"
  14
  15
  16 extern LZMA_API(lzma_ret)
  17 lzma_raw_buffer_decode(
  18                 const lzma_filter *filters, const lzma_allocator *allocator,
  19                 const uint8_t *in, size_t *in_pos, size_t in_size,
  20                 uint8_t *out, size_t *out_pos, size_t out_size)
  21 {
  22         // Validate what isn't validated later in filter_common.c.
  23         if (in == NULL || in_pos == NULL || *in_pos > in_size || out == NULL
  24                         || out_pos == NULL || *out_pos > out_size)
  25                 return LZMA_PROG_ERROR;
  26
  27         // Initialize the decoer.
  28         lzma_next_coder next = LZMA_NEXT_CODER_INIT;
  29         return_if_error(lzma_raw_decoder_init(&next, allocator, filters));
  30
  31         // Store the positions so that we can restore them if something
  32         // goes wrong.
  33         const size_t in_start = *in_pos;
  34         const size_t out_start = *out_pos;
  35
  36         // Do the actual decoding and free decoder's memory.
  37         lzma_ret ret = next.code(next.coder, allocator, in, in_pos, in_size,
  38                         out, out_pos, out_size, LZMA_FINISH);
  39
  40         if (ret == LZMA_STREAM_END) {
  41                 ret = LZMA_OK;
  42         } else {
  43                 if (ret == LZMA_OK) {
  44                         // Either the input was truncated or the
  45                         // output buffer was too small.
  46                         assert(*in_pos == in_size || *out_pos == out_size);
  47
  48                         if (*in_pos != in_size) {
  49                                 // Since input wasn't consumed completely,
  50                                 // the output buffer became full and is
  51                                 // too small.
  52                                 ret = LZMA_BUF_ERROR;
  53
  54                         } else if (*out_pos != out_size) {
  55                                 // Since output didn't became full, the input
  56                                 // has to be truncated.
  57                                 ret = LZMA_DATA_ERROR;
  58
  59                         } else {
  60                                 // All the input was consumed and output
  61                                 // buffer is full. Now we don't immediately
  62                                 // know the reason for the error. Try
  63                                 // decoding one more byte. If it succeeds,
  64                                 // then the output buffer was too small. If
  65                                 // we cannot get a new output byte, the input
  66                                 // is truncated.
  67                                 uint8_t tmp[1];
  68                                 size_t tmp_pos = 0;
  69                                 (void)next.code(next.coder, allocator,
  70                                                 in, in_pos, in_size,
  71                                                 tmp, &tmp_pos, 1, LZMA_FINISH);
  72
  73                                 if (tmp_pos == 1)
  74                                         ret = LZMA_BUF_ERROR;
  75                                 else
  76                                         ret = LZMA_DATA_ERROR;
  77                         }
  78                 }
  79
  80                 // Restore the positions.
  81                 *in_pos = in_start;
  82                 *out_pos = out_start;
  83         }
  84
  85         lzma_next_end(&next, allocator);
  86
  87         return ret;
  88 }