xref: /isa-l_crypto/rolling_hash/rolling_hashx_internal.h (revision 1e0b122e090c8ad3a8d8c56e182f754ea26fe70d)

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/**
 *  @file  rolling_hashx_internal.h
 *  @brief Internal fingerprint functions based on rolling hash
 *
 *  rolling_hash2 - checks hash in a sliding window based on random 64-bit hash.
 */

#ifndef _ROLLING_INTERNAL_HASHX_H_
#define _ROLLING_INTERNAL_HASHX_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include "rolling_hashx.h"

/**
 * @brief Initialize state object for rolling hash2
 *
 * @param state Structure holding state info on current rolling hash
 * @param w     Window width (1 <= w <= 32)
 * @returns 0 - success, -1 - failure
 */
int
_rolling_hash2_init(struct isal_rh_state2 *state, uint32_t w);

/**
 * @brief Reset the hash state history
 *
 * @param state Structure holding state info on current rolling hash
 * @param init_bytes Optional window size buffer to pre-init hash
 * @returns none
 */
void
_rolling_hash2_reset(struct isal_rh_state2 *state, uint8_t *init_bytes);

/**
 * @brief Run rolling hash function until trigger met or max length reached
 *
 * Checks for trigger based on a random hash in a sliding window.
 * @param state   Structure holding state info on current rolling hash
 * @param buffer  Pointer to input buffer to run windowed hash on
 * @param max_len Max length to run over input
 * @param mask    Mask bits ORed with hash before test with trigger
 * @param trigger Match value to compare with windowed hash at each input byte
 * @param offset  Offset from buffer to match, set if match found
 * @returns ISAL_FINGERPRINT_RET_HIT - match found, ISAL_FINGERPRINT_RET_MAX - exceeded max length
 */
int
_rolling_hash2_run(struct isal_rh_state2 *state, uint8_t *buffer, uint32_t max_len, uint32_t mask,
                   uint32_t trigger, uint32_t *offset);

/**
 * @brief Generate an appropriate mask to target mean hit rate
 *
 * @param mean  Target chunk size in bytes
 * @param shift Bits to rotate result to get independent masks
 * @returns 32-bit mask value
 */
uint32_t
_rolling_hashx_mask_gen(long mean, int shift);

#ifdef __cplusplus
}
#endif

#endif // _ROLLING_INTERNAL_HASHX_H_