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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 }