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(const lzma_filter *filters, lzma_allocator *allocator,
  18                 const uint8_t *in, size_t *in_pos, size_t in_size,
  19                 uint8_t *out, size_t *out_pos, size_t out_size)
  20 {
  21         // Validate what isn't validated later in filter_common.c.
  22         if (in == NULL || in_pos == NULL || *in_pos > in_size || out == NULL
  23                         || out_pos == NULL || *out_pos > out_size)
  24                 return LZMA_PROG_ERROR;
  25
  26         // Initialize the decoer.
  27         lzma_next_coder next = LZMA_NEXT_CODER_INIT;
  28         return_if_error(lzma_raw_decoder_init(&next, allocator, filters));
  29
  30         // Store the positions so that we can restore them if something
  31         // goes wrong.
  32         const size_t in_start = *in_pos;
  33         const size_t out_start = *out_pos;
  34
  35         // Do the actual decoding and free decoder's memory.
  36         lzma_ret ret = next.code(next.coder, allocator, in, in_pos, in_size,
  37                         out, out_pos, out_size, LZMA_FINISH);
  38
  39         if (ret == LZMA_STREAM_END) {
  40                 ret = LZMA_OK;
  41         } else {
  42                 if (ret == LZMA_OK) {
  43                         // Either the input was truncated or the
  44                         // output buffer was too small.
  45                         assert(*in_pos == in_size || *out_pos == out_size);
  46
  47                         if (*in_pos != in_size) {
  48                                 // Since input wasn't consumed completely,
  49                                 // the output buffer became full and is
  50                                 // too small.
  51                                 ret = LZMA_BUF_ERROR;
  52
  53                         } else if (*out_pos != out_size) {
  54                                 // Since output didn't became full, the input
  55                                 // has to be truncated.
  56                                 ret = LZMA_DATA_ERROR;
  57
  58                         } else {
  59                                 // All the input was consumed and output
  60                                 // buffer is full. Now we don't immediatelly
  61                                 // know the reason for the error. Try
  62                                 // decoding one more byte. If it succeeds,
  63                                 // then the output buffer was too small. If
  64                                 // we cannot get a new output byte, the input
  65                                 // is truncated.
  66                                 uint8_t tmp[1];
  67                                 size_t tmp_pos = 0;
  68                                 (void)next.code(next.coder, allocator,
  69                                                 in, in_pos, in_size,
  70                                                 tmp, &tmp_pos, 1, LZMA_FINISH);
  71
  72                                 if (tmp_pos == 1)
  73                                         ret = LZMA_BUF_ERROR;
  74                                 else
  75                                         ret = LZMA_DATA_ERROR;
  76                         }
  77                 }
  78
  79                 // Restore the positions.
  80                 *in_pos = in_start;
  81                 *out_pos = out_start;
  82         }
  83
  84         lzma_next_end(&next, allocator);
  85
  86         return ret;
  87 }