aboutsummaryrefslogtreecommitdiff
path: root/src/liblzma/api/lzma/check.h
blob: 6a243db0d7943a1df878928a3456ed7516789f66 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
/**
 * \file        lzma/check.h
 * \brief       Integrity checks
 */

/*
 * Author: Lasse Collin
 *
 * This file has been put into the public domain.
 * You can do whatever you want with this file.
 *
 * See ../lzma.h for information about liblzma as a whole.
 */

#ifndef LZMA_H_INTERNAL
#	error Never include this file directly. Use <lzma.h> instead.
#endif


/**
 * \brief       Type of the integrity check (Check ID)
 *
 * The .xz format supports multiple types of checks that are calculated
 * from the uncompressed data. They vary in both speed and ability to
 * detect errors.
 */
typedef enum {
	LZMA_CHECK_NONE     = 0,
		/**<
		 * No Check is calculated.
		 *
		 * Size of the Check field: 0 bytes
		 */

	LZMA_CHECK_CRC32    = 1,
		/**<
		 * CRC32 using the polynomial from the IEEE 802.3 standard
		 *
		 * Size of the Check field: 4 bytes
		 */

	LZMA_CHECK_CRC64    = 4,
		/**<
		 * CRC64 using the polynomial from the ECMA-182 standard
		 *
		 * Size of the Check field: 8 bytes
		 */

	LZMA_CHECK_SHA256   = 10
		/**<
		 * SHA-256
		 *
		 * Size of the Check field: 32 bytes
		 */
} lzma_check;


/**
 * \brief       Maximum valid Check ID
 *
 * The .xz file format specification specifies 16 Check IDs (0-15). Some
 * of them are only reserved, that is, no actual Check algorithm has been
 * assigned. When decoding, liblzma still accepts unknown Check IDs for
 * future compatibility. If a valid but unsupported Check ID is detected,
 * liblzma can indicate a warning; see the flags LZMA_TELL_NO_CHECK,
 * LZMA_TELL_UNSUPPORTED_CHECK, and LZMA_TELL_ANY_CHECK in container.h.
 */
#define LZMA_CHECK_ID_MAX 15


/**
 * \brief       Test if the given Check ID is supported
 *
 * Return true if the given Check ID is supported by this liblzma build.
 * Otherwise false is returned. It is safe to call this with a value that
 * is not in the range [0, 15]; in that case the return value is always false.
 *
 * You can assume that LZMA_CHECK_NONE and LZMA_CHECK_CRC32 are always
 * supported (even if liblzma is built with limited features).
 */
extern LZMA_API(lzma_bool) lzma_check_is_supported(lzma_check check)
		lzma_nothrow lzma_attr_const;


/**
 * \brief       Get the size of the Check field with the given Check ID
 *
 * Although not all Check IDs have a check algorithm associated, the size of
 * every Check is already frozen. This function returns the size (in bytes) of
 * the Check field with the specified Check ID. The values are:
 * { 0, 4, 4, 4, 8, 8, 8, 16, 16, 16, 32, 32, 32, 64, 64, 64 }
 *
 * If the argument is not in the range [0, 15], UINT32_MAX is returned.
 */
extern LZMA_API(uint32_t) lzma_check_size(lzma_check check)
		lzma_nothrow lzma_attr_const;


/**
 * \brief       Maximum size of a Check field
 */
#define LZMA_CHECK_SIZE_MAX 64


/**
 * \brief       Calculate CRC32
 *
 * Calculate CRC32 using the polynomial from the IEEE 802.3 standard.
 *
 * \param       buf     Pointer to the input buffer
 * \param       size    Size of the input buffer
 * \param       crc     Previously returned CRC value. This is used to
 *                      calculate the CRC of a big buffer in smaller chunks.
 *                      Set to zero when starting a new calculation.
 *
 * \return      Updated CRC value, which can be passed to this function
 *              again to continue CRC calculation.
 */
extern LZMA_API(uint32_t) lzma_crc32(
		const uint8_t *buf, size_t size, uint32_t crc)
		lzma_nothrow lzma_attr_pure;


/**
 * \brief       Calculate CRC64
 *
 * Calculate CRC64 using the polynomial from the ECMA-182 standard.
 *
 * This function is used similarly to lzma_crc32(). See its documentation.
 */
extern LZMA_API(uint64_t) lzma_crc64(
		const uint8_t *buf, size_t size, uint64_t crc)
		lzma_nothrow lzma_attr_pure;


/*
 * SHA-256 functions are currently not exported to public API.
 * Contact Lasse Collin if you think it should be.
 */


/**
 * \brief       Get the type of the integrity check
 *
 * This function can be called only immediately after lzma_code() has
 * returned LZMA_NO_CHECK, LZMA_UNSUPPORTED_CHECK, or LZMA_GET_CHECK.
 * Calling this function in any other situation has undefined behavior.
 */
extern LZMA_API(lzma_check) lzma_get_check(const lzma_stream *strm)
		lzma_nothrow;