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lzma
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check.h
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/** * \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;
