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| 1 /** |
| 2 * \file lzma/check.h |
| 3 * \brief Integrity checks |
| 4 */ |
| 5 |
| 6 /* |
| 7 * Author: Lasse Collin |
| 8 * |
| 9 * This file has been put into the public domain. |
| 10 * You can do whatever you want with this file. |
| 11 * |
| 12 * See ../lzma.h for information about liblzma as a whole. |
| 13 */ |
| 14 |
| 15 #ifndef LZMA_H_INTERNAL |
| 16 # error Never include this file directly. Use <lzma.h> instead. |
| 17 #endif |
| 18 |
| 19 |
| 20 /** |
| 21 * \brief Type of the integrity check (Check ID) |
| 22 * |
| 23 * The .xz format supports multiple types of checks that are calculated |
| 24 * from the uncompressed data. They vary in both speed and ability to |
| 25 * detect errors. |
| 26 */ |
| 27 typedef enum { |
| 28 LZMA_CHECK_NONE = 0, |
| 29 /**< |
| 30 * No Check is calculated. |
| 31 * |
| 32 * Size of the Check field: 0 bytes |
| 33 */ |
| 34 |
| 35 LZMA_CHECK_CRC32 = 1, |
| 36 /**< |
| 37 * CRC32 using the polynomial from the IEEE 802.3 standard |
| 38 * |
| 39 * Size of the Check field: 4 bytes |
| 40 */ |
| 41 |
| 42 LZMA_CHECK_CRC64 = 4, |
| 43 /**< |
| 44 * CRC64 using the polynomial from the ECMA-182 standard |
| 45 * |
| 46 * Size of the Check field: 8 bytes |
| 47 */ |
| 48 |
| 49 LZMA_CHECK_SHA256 = 10 |
| 50 /**< |
| 51 * SHA-256 |
| 52 * |
| 53 * Size of the Check field: 32 bytes |
| 54 */ |
| 55 } lzma_check; |
| 56 |
| 57 |
| 58 /** |
| 59 * \brief Maximum valid Check ID |
| 60 * |
| 61 * The .xz file format specification specifies 16 Check IDs (0-15). Some |
| 62 * of them are only reserved, that is, no actual Check algorithm has been |
| 63 * assigned. When decoding, liblzma still accepts unknown Check IDs for |
| 64 * future compatibility. If a valid but unsupported Check ID is detected, |
| 65 * liblzma can indicate a warning; see the flags LZMA_TELL_NO_CHECK, |
| 66 * LZMA_TELL_UNSUPPORTED_CHECK, and LZMA_TELL_ANY_CHECK in container.h. |
| 67 */ |
| 68 #define LZMA_CHECK_ID_MAX 15 |
| 69 |
| 70 |
| 71 /** |
| 72 * \brief Test if the given Check ID is supported |
| 73 * |
| 74 * Return true if the given Check ID is supported by this liblzma build. |
| 75 * Otherwise false is returned. It is safe to call this with a value that |
| 76 * is not in the range [0, 15]; in that case the return value is always false. |
| 77 * |
| 78 * You can assume that LZMA_CHECK_NONE and LZMA_CHECK_CRC32 are always |
| 79 * supported (even if liblzma is built with limited features). |
| 80 */ |
| 81 extern LZMA_API(lzma_bool) lzma_check_is_supported(lzma_check check) |
| 82 lzma_nothrow lzma_attr_const; |
| 83 |
| 84 |
| 85 /** |
| 86 * \brief Get the size of the Check field with the given Check ID |
| 87 * |
| 88 * Although not all Check IDs have a check algorithm associated, the size of |
| 89 * every Check is already frozen. This function returns the size (in bytes) of |
| 90 * the Check field with the specified Check ID. The values are: |
| 91 * { 0, 4, 4, 4, 8, 8, 8, 16, 16, 16, 32, 32, 32, 64, 64, 64 } |
| 92 * |
| 93 * If the argument is not in the range [0, 15], UINT32_MAX is returned. |
| 94 */ |
| 95 extern LZMA_API(uint32_t) lzma_check_size(lzma_check check) |
| 96 lzma_nothrow lzma_attr_const; |
| 97 |
| 98 |
| 99 /** |
| 100 * \brief Maximum size of a Check field |
| 101 */ |
| 102 #define LZMA_CHECK_SIZE_MAX 64 |
| 103 |
| 104 |
| 105 /** |
| 106 * \brief Calculate CRC32 |
| 107 * |
| 108 * Calculate CRC32 using the polynomial from the IEEE 802.3 standard. |
| 109 * |
| 110 * \param buf Pointer to the input buffer |
| 111 * \param size Size of the input buffer |
| 112 * \param crc Previously returned CRC value. This is used to |
| 113 * calculate the CRC of a big buffer in smaller chunks. |
| 114 * Set to zero when starting a new calculation. |
| 115 * |
| 116 * \return Updated CRC value, which can be passed to this function |
| 117 * again to continue CRC calculation. |
| 118 */ |
| 119 extern LZMA_API(uint32_t) lzma_crc32( |
| 120 const uint8_t *buf, size_t size, uint32_t crc) |
| 121 lzma_nothrow lzma_attr_pure; |
| 122 |
| 123 |
| 124 /** |
| 125 * \brief Calculate CRC64 |
| 126 * |
| 127 * Calculate CRC64 using the polynomial from the ECMA-182 standard. |
| 128 * |
| 129 * This function is used similarly to lzma_crc32(). See its documentation. |
| 130 */ |
| 131 extern LZMA_API(uint64_t) lzma_crc64( |
| 132 const uint8_t *buf, size_t size, uint64_t crc) |
| 133 lzma_nothrow lzma_attr_pure; |
| 134 |
| 135 |
| 136 /* |
| 137 * SHA-256 functions are currently not exported to public API. |
| 138 * Contact Lasse Collin if you think it should be. |
| 139 */ |
| 140 |
| 141 |
| 142 /** |
| 143 * \brief Get the type of the integrity check |
| 144 * |
| 145 * This function can be called only immediately after lzma_code() has |
| 146 * returned LZMA_NO_CHECK, LZMA_UNSUPPORTED_CHECK, or LZMA_GET_CHECK. |
| 147 * Calling this function in any other situation has undefined behavior. |
| 148 */ |
| 149 extern LZMA_API(lzma_check) lzma_get_check(const lzma_stream *strm) |
| 150 lzma_nothrow; |
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