pd.if.org Git - zpackage/blob - lzma/common/block_util.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       block_header.c
   4 /// \brief      Utility functions to handle lzma_block
   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 "common.h"
  14 #include "index.h"
  15
  16
  17 extern LZMA_API(lzma_ret)
  18 lzma_block_compressed_size(lzma_block *block, lzma_vli unpadded_size)
  19 {
  20         // Validate everything but Uncompressed Size and filters.
  21         if (lzma_block_unpadded_size(block) == 0)
  22                 return LZMA_PROG_ERROR;
  23
  24         const uint32_t container_size = block->header_size
  25                         + lzma_check_size(block->check);
  26
  27         // Validate that Compressed Size will be greater than zero.
  28         if (unpadded_size <= container_size)
  29                 return LZMA_DATA_ERROR;
  30
  31         // Calculate what Compressed Size is supposed to be.
  32         // If Compressed Size was present in Block Header,
  33         // compare that the new value matches it.
  34         const lzma_vli compressed_size = unpadded_size - container_size;
  35         if (block->compressed_size != LZMA_VLI_UNKNOWN
  36                         && block->compressed_size != compressed_size)
  37                 return LZMA_DATA_ERROR;
  38
  39         block->compressed_size = compressed_size;
  40
  41         return LZMA_OK;
  42 }
  43
  44
  45 extern LZMA_API(lzma_vli)
  46 lzma_block_unpadded_size(const lzma_block *block)
  47 {
  48         // Validate the values that we are interested in i.e. all but
  49         // Uncompressed Size and the filters.
  50         //
  51         // NOTE: This function is used for validation too, so it is
  52         // essential that these checks are always done even if
  53         // Compressed Size is unknown.
  54         if (block == NULL || block->version > 1
  55                         || block->header_size < LZMA_BLOCK_HEADER_SIZE_MIN
  56                         || block->header_size > LZMA_BLOCK_HEADER_SIZE_MAX
  57                         || (block->header_size & 3)
  58                         || !lzma_vli_is_valid(block->compressed_size)
  59                         || block->compressed_size == 0
  60                         || (unsigned int)(block->check) > LZMA_CHECK_ID_MAX)
  61                 return 0;
  62
  63         // If Compressed Size is unknown, return that we cannot know
  64         // size of the Block either.
  65         if (block->compressed_size == LZMA_VLI_UNKNOWN)
  66                 return LZMA_VLI_UNKNOWN;
  67
  68         // Calculate Unpadded Size and validate it.
  69         const lzma_vli unpadded_size = block->compressed_size
  70                                 + block->header_size
  71                                 + lzma_check_size(block->check);
  72
  73         assert(unpadded_size >= UNPADDED_SIZE_MIN);
  74         if (unpadded_size > UNPADDED_SIZE_MAX)
  75                 return 0;
  76
  77         return unpadded_size;
  78 }
  79
  80
  81 extern LZMA_API(lzma_vli)
  82 lzma_block_total_size(const lzma_block *block)
  83 {
  84         lzma_vli unpadded_size = lzma_block_unpadded_size(block);
  85
  86         if (unpadded_size != LZMA_VLI_UNKNOWN)
  87                 unpadded_size = vli_ceil4(unpadded_size);
  88
  89         return unpadded_size;
  90 }