root/hash/hash_fnv.c

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DEFINITIONS

This source file includes following definitions.
  1. PHP_FNV132Init
  2. PHP_FNV132Update
  3. PHP_FNV1a32Update
  4. PHP_FNV132Final
  5. PHP_FNV164Init
  6. PHP_FNV164Update
  7. PHP_FNV1a64Update
  8. PHP_FNV164Final
  9. fnv_32_buf
  10. fnv_64_buf

/*
  +----------------------------------------------------------------------+
  | PHP Version 5                                                        |
  +----------------------------------------------------------------------+
  | Copyright (c) 1997-2013 The PHP Group                                |
  +----------------------------------------------------------------------+
  | This source file is subject to version 3.01 of the PHP license,      |
  | that is bundled with this package in the file LICENSE, and is        |
  | available through the world-wide-web at the following url:           |
  | http://www.php.net/license/3_01.txt                                  |
  | If you did not receive a copy of the PHP license and are unable to   |
  | obtain it through the world-wide-web, please send a note to          |
  | license@php.net so we can mail you a copy immediately.               |
  +----------------------------------------------------------------------+
  | Author: Michael Maclean <mgdm@php.net>                               |
  +----------------------------------------------------------------------+
*/

/* $Id$ */

/*  Based on the public domain algorithm found at
        http://www.isthe.com/chongo/tech/comp/fnv/index.html */

#include "php_hash.h"
#include "php_hash_fnv.h"

const php_hash_ops php_hash_fnv132_ops = {
        (php_hash_init_func_t) PHP_FNV132Init,
        (php_hash_update_func_t) PHP_FNV132Update,
        (php_hash_final_func_t) PHP_FNV132Final,
        (php_hash_copy_func_t) php_hash_copy,
        4,
        4,
        sizeof(PHP_FNV132_CTX)
};

        const php_hash_ops php_hash_fnv1a32_ops = {
        (php_hash_init_func_t) PHP_FNV132Init,
        (php_hash_update_func_t) PHP_FNV1a32Update,
        (php_hash_final_func_t) PHP_FNV132Final, 
        (php_hash_copy_func_t) php_hash_copy,
        4,
        4,
        sizeof(PHP_FNV132_CTX)
};

const php_hash_ops php_hash_fnv164_ops = {
        (php_hash_init_func_t) PHP_FNV164Init,
        (php_hash_update_func_t) PHP_FNV164Update,
        (php_hash_final_func_t) PHP_FNV164Final, 
        (php_hash_copy_func_t) php_hash_copy,
        8,
        4,
        sizeof(PHP_FNV164_CTX)
};

const php_hash_ops php_hash_fnv1a64_ops = {
        (php_hash_init_func_t) PHP_FNV164Init,
        (php_hash_update_func_t) PHP_FNV1a64Update,
        (php_hash_final_func_t) PHP_FNV164Final,  
        (php_hash_copy_func_t) php_hash_copy,
        8,
        4,
        sizeof(PHP_FNV164_CTX)
};

/* {{{ PHP_FNV132Init
 * 32-bit FNV-1 hash initialisation
 */
PHP_HASH_API void PHP_FNV132Init(PHP_FNV132_CTX *context)
{
        context->state = PHP_FNV1_32_INIT;
}
/* }}} */

PHP_HASH_API void PHP_FNV132Update(PHP_FNV132_CTX *context, const unsigned char *input,
                unsigned int inputLen)
{
        context->state = fnv_32_buf((void *)input, inputLen, context->state, 0);
}

PHP_HASH_API void PHP_FNV1a32Update(PHP_FNV132_CTX *context, const unsigned char *input,
                unsigned int inputLen)
{
        context->state = fnv_32_buf((void *)input, inputLen, context->state, 1);
}

PHP_HASH_API void PHP_FNV132Final(unsigned char digest[4], PHP_FNV132_CTX * context)
{
#ifdef WORDS_BIGENDIAN
        memcpy(digest, &context->state, 4);
#else
        int i = 0;
        unsigned char *c = (unsigned char *) &context->state;

        for (i = 0; i < 4; i++) {
                digest[i] = c[3 - i];
        }
#endif
}

/* {{{ PHP_FNV164Init
 * 64-bit FNV-1 hash initialisation
 */
PHP_HASH_API void PHP_FNV164Init(PHP_FNV164_CTX *context)
{
        context->state = PHP_FNV1_64_INIT;
}
/* }}} */

PHP_HASH_API void PHP_FNV164Update(PHP_FNV164_CTX *context, const unsigned char *input,
                unsigned int inputLen)
{
        context->state = fnv_64_buf((void *)input, inputLen, context->state, 0);
}

PHP_HASH_API void PHP_FNV1a64Update(PHP_FNV164_CTX *context, const unsigned char *input,
                unsigned int inputLen)
{
        context->state = fnv_64_buf((void *)input, inputLen, context->state, 1);
}

PHP_HASH_API void PHP_FNV164Final(unsigned char digest[8], PHP_FNV164_CTX * context)
{
#ifdef WORDS_BIGENDIAN
        memcpy(digest, &context->state, 8);
#else
        int i = 0;
        unsigned char *c = (unsigned char *) &context->state;

        for (i = 0; i < 8; i++) {
                digest[i] = c[7 - i];
        }
#endif
}


/*
 * fnv_32_buf - perform a 32 bit Fowler/Noll/Vo hash on a buffer
 *
 * input:
 *  buf - start of buffer to hash
 *  len - length of buffer in octets
 *  hval        - previous hash value or 0 if first call
 *  alternate - if > 0 use the alternate version
 *
 * returns:
 *  32 bit hash as a static hash type
 */
static php_hash_uint32
fnv_32_buf(void *buf, size_t len, php_hash_uint32 hval, int alternate)
{
        unsigned char *bp = (unsigned char *)buf;   /* start of buffer */
        unsigned char *be = bp + len;      /* beyond end of buffer */

        /*
         * FNV-1 hash each octet in the buffer
         */
        while (bp < be) {

                if (alternate == 0) {
                        /* multiply by the 32 bit FNV magic prime mod 2^32 */
                        hval *= PHP_FNV_32_PRIME;

                        /* xor the bottom with the current octet */
                        hval ^= (php_hash_uint32)*bp++;
                } else {
                        /* xor the bottom with the current octet */
                        hval ^= (php_hash_uint32)*bp++;

                        /* multiply by the 32 bit FNV magic prime mod 2^32 */
                        hval *= PHP_FNV_32_PRIME;
                }
        }

        /* return our new hash value */
        return hval;
}

/*
 * fnv_64_buf - perform a 64 bit Fowler/Noll/Vo hash on a buffer
 *
 * input:
 *  buf - start of buffer to hash
 *  len - length of buffer in octets
 *  hval        - previous hash value or 0 if first call
 *  alternate - if > 0 use the alternate version
 *
 * returns:
 *  64 bit hash as a static hash type
 */
static php_hash_uint64
fnv_64_buf(void *buf, size_t len, php_hash_uint64 hval, int alternate)
{
        unsigned char *bp = (unsigned char *)buf;   /* start of buffer */
        unsigned char *be = bp + len;      /* beyond end of buffer */

        /*
         * FNV-1 hash each octet of the buffer
         */
        while (bp < be) {

                if (alternate == 0) {
                        /* multiply by the 64 bit FNV magic prime mod 2^64 */
                        hval *= PHP_FNV_64_PRIME;

                        /* xor the bottom with the current octet */
                        hval ^= (php_hash_uint64)*bp++;
                 } else {
                        /* xor the bottom with the current octet */
                        hval ^= (php_hash_uint64)*bp++;

                        /* multiply by the 64 bit FNV magic prime mod 2^64 */
                        hval *= PHP_FNV_64_PRIME;
                 }
        }

        /* return our new hash value */
        return hval;
}

/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 * vim600: noet sw=4 ts=4 fdm=marker
 * vim<600: noet sw=4 ts=4
 */

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