| 49813 |
ripley |
1 |
///////////////////////////////////////////////////////////////////////////////
|
|
|
2 |
//
|
|
|
3 |
/// \file block_header_decoder.c
|
|
|
4 |
/// \brief Decodes Block Header from .xz files
|
|
|
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 "check.h"
|
|
|
15 |
|
|
|
16 |
|
|
|
17 |
static void
|
|
|
18 |
free_properties(lzma_block *block, lzma_allocator *allocator)
|
|
|
19 |
{
|
|
|
20 |
// Free allocated filter options. The last array member is not
|
|
|
21 |
// touched after the initialization in the beginning of
|
|
|
22 |
// lzma_block_header_decode(), so we don't need to touch that here.
|
|
|
23 |
for (size_t i = 0; i < LZMA_FILTERS_MAX; ++i) {
|
|
|
24 |
lzma_free(block->filters[i].options, allocator);
|
|
|
25 |
block->filters[i].id = LZMA_VLI_UNKNOWN;
|
|
|
26 |
block->filters[i].options = NULL;
|
|
|
27 |
}
|
|
|
28 |
|
|
|
29 |
return;
|
|
|
30 |
}
|
|
|
31 |
|
|
|
32 |
|
|
|
33 |
extern LZMA_API(lzma_ret)
|
|
|
34 |
lzma_block_header_decode(lzma_block *block,
|
|
|
35 |
lzma_allocator *allocator, const uint8_t *in)
|
|
|
36 |
{
|
|
|
37 |
// NOTE: We consider the header to be corrupt not only when the
|
|
|
38 |
// CRC32 doesn't match, but also when variable-length integers
|
|
|
39 |
// are invalid or over 63 bits, or if the header is too small
|
|
|
40 |
// to contain the claimed information.
|
|
|
41 |
|
|
|
42 |
// Initialize the filter options array. This way the caller can
|
|
|
43 |
// safely free() the options even if an error occurs in this function.
|
|
|
44 |
for (size_t i = 0; i <= LZMA_FILTERS_MAX; ++i) {
|
|
|
45 |
block->filters[i].id = LZMA_VLI_UNKNOWN;
|
|
|
46 |
block->filters[i].options = NULL;
|
|
|
47 |
}
|
|
|
48 |
|
|
|
49 |
// Always zero for now.
|
|
|
50 |
block->version = 0;
|
|
|
51 |
|
|
|
52 |
// Validate Block Header Size and Check type. The caller must have
|
|
|
53 |
// already set these, so it is a programming error if this test fails.
|
|
|
54 |
if (lzma_block_header_size_decode(in[0]) != block->header_size
|
|
|
55 |
|| (unsigned int)(block->check) > LZMA_CHECK_ID_MAX)
|
|
|
56 |
return LZMA_PROG_ERROR;
|
|
|
57 |
|
|
|
58 |
// Exclude the CRC32 field.
|
|
|
59 |
const size_t in_size = block->header_size - 4;
|
|
|
60 |
|
|
|
61 |
// Verify CRC32
|
| 53508 |
ripley |
62 |
if (lzma_crc32(in, in_size, 0) != unaligned_read32le(in + in_size))
|
| 49813 |
ripley |
63 |
return LZMA_DATA_ERROR;
|
|
|
64 |
|
|
|
65 |
// Check for unsupported flags.
|
|
|
66 |
if (in[1] & 0x3C)
|
|
|
67 |
return LZMA_OPTIONS_ERROR;
|
|
|
68 |
|
|
|
69 |
// Start after the Block Header Size and Block Flags fields.
|
|
|
70 |
size_t in_pos = 2;
|
|
|
71 |
|
|
|
72 |
// Compressed Size
|
|
|
73 |
if (in[1] & 0x40) {
|
|
|
74 |
return_if_error(lzma_vli_decode(&block->compressed_size,
|
|
|
75 |
NULL, in, &in_pos, in_size));
|
|
|
76 |
|
|
|
77 |
// Validate Compressed Size. This checks that it isn't zero
|
|
|
78 |
// and that the total size of the Block is a valid VLI.
|
|
|
79 |
if (lzma_block_unpadded_size(block) == 0)
|
|
|
80 |
return LZMA_DATA_ERROR;
|
|
|
81 |
} else {
|
|
|
82 |
block->compressed_size = LZMA_VLI_UNKNOWN;
|
|
|
83 |
}
|
|
|
84 |
|
|
|
85 |
// Uncompressed Size
|
|
|
86 |
if (in[1] & 0x80)
|
|
|
87 |
return_if_error(lzma_vli_decode(&block->uncompressed_size,
|
|
|
88 |
NULL, in, &in_pos, in_size));
|
|
|
89 |
else
|
|
|
90 |
block->uncompressed_size = LZMA_VLI_UNKNOWN;
|
|
|
91 |
|
|
|
92 |
// Filter Flags
|
|
|
93 |
const size_t filter_count = (in[1] & 3) + 1;
|
|
|
94 |
for (size_t i = 0; i < filter_count; ++i) {
|
|
|
95 |
const lzma_ret ret = lzma_filter_flags_decode(
|
|
|
96 |
&block->filters[i], allocator,
|
|
|
97 |
in, &in_pos, in_size);
|
|
|
98 |
if (ret != LZMA_OK) {
|
|
|
99 |
free_properties(block, allocator);
|
|
|
100 |
return ret;
|
|
|
101 |
}
|
|
|
102 |
}
|
|
|
103 |
|
|
|
104 |
// Padding
|
|
|
105 |
while (in_pos < in_size) {
|
|
|
106 |
if (in[in_pos++] != 0x00) {
|
|
|
107 |
free_properties(block, allocator);
|
|
|
108 |
|
|
|
109 |
// Possibly some new field present so use
|
|
|
110 |
// LZMA_OPTIONS_ERROR instead of LZMA_DATA_ERROR.
|
|
|
111 |
return LZMA_OPTIONS_ERROR;
|
|
|
112 |
}
|
|
|
113 |
}
|
|
|
114 |
|
|
|
115 |
return LZMA_OK;
|
|
|
116 |
}
|
The R Project SVN
R