path: root/src/liblzma/check/check.h

///////////////////////////////////////////////////////////////////////////////
//
/// \file       check.h
/// \brief      Internal API to different integrity check functions
//
//  This code has been put into the public domain.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//
///////////////////////////////////////////////////////////////////////////////

#ifndef LZMA_CHECK_H
#define LZMA_CHECK_H

#include "common.h"


// Index hashing needs the best possible hash function (preferably
// a cryptographic hash) for maximum reliability.
#if defined(HAVE_CHECK_SHA256)
#	define LZMA_CHECK_BEST LZMA_CHECK_SHA256
#elif defined(HAVE_CHECK_CRC64)
#	define LZMA_CHECK_BEST LZMA_CHECK_CRC64
#else
#	define LZMA_CHECK_BEST LZMA_CHECK_CRC32
#endif


/// \brief      Structure to hold internal state of the check being calculated
///
/// \note       This is not in the public API because this structure may
///             change in future if new integrity check algorithms are added.
typedef struct {
	/// Buffer to hold the final result and a temporary buffer for SHA256.
	union {
		uint8_t u8[64];
		uint32_t u32[16];
		uint64_t u64[8];
	} buffer;

	/// Check-specific data
	union {
		uint32_t crc32;
		uint64_t crc64;

		struct {
			/// Internal state
			uint32_t state[8];

			/// Size of the message excluding padding
			uint64_t size;
		} sha256;
	} state;

} lzma_check_state;


#ifdef HAVE_SMALL
extern uint32_t lzma_crc32_table[8][256];
extern uint64_t lzma_crc64_table[4][256];
#else
extern const uint32_t lzma_crc32_table[8][256];
extern const uint64_t lzma_crc64_table[4][256];
#endif


/// \brief      Initializes *check depending on type
///
/// \return     LZMA_OK on success. LZMA_UNSUPPORTED_CHECK if the type is not
///             supported by the current version or build of liblzma.
///             LZMA_PROG_ERROR if type > LZMA_CHECK_ID_MAX.
///
extern void lzma_check_init(lzma_check_state *check, lzma_check type);


/// \brief      Updates *check
///
extern void lzma_check_update(lzma_check_state *check, lzma_check type,
		const uint8_t *buf, size_t size);


/// \brief      Finishes *check
///
extern void lzma_check_finish(lzma_check_state *check, lzma_check type);


extern void lzma_crc32_init(void);


extern void lzma_crc64_init(void);


extern void lzma_sha256_init(lzma_check_state *check);

extern void lzma_sha256_update(
		const uint8_t *buf, size_t size, lzma_check_state *check);

extern void lzma_sha256_finish(lzma_check_state *check);

#endif