nginx 0.9.0 *) Feature: the "keepalive_disable" directive. *) Feature: the "map" directive supports variables as value of a defined variable. *) Feature: the "map" directive supports empty strings as value of the first parameter. *) Feature: the "map" directive supports expressions as the first parameter. *) Feature: nginx(8) manual page. Thanks to Sergey Osokin. *) Feature: Linux accept4() support. Thanks to Simon Liu. *) Workaround: elimination of Linux linker warning about "sys_errlist" and "sys_nerr"; the warning had appeared in 0.8.35. *) Bugfix: a segmentation fault might occur in a worker process, if the "auth_basic" directive was used. Thanks to Michail Laletin. *) Bugfix: compatibility with ngx_http_eval_module; the bug had appeared in 0.8.42.

/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_CRC_H_INCLUDED_
#define _NGX_CRC_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


/* 32-bit crc16 */

static ngx_inline uint32_t
ngx_crc(u_char *data, size_t len)
{
    uint32_t  sum;

    for (sum = 0; len; len--) {

        /*
         * gcc 2.95.2 x86 and icc 7.1.006 compile
         * that operator into the single "rol" opcode,
         * msvc 6.0sp2 compiles it into four opcodes.
         */
        sum = sum >> 1 | sum << 31;

        sum += *data++;
    }

    return sum;
}


#endif /* _NGX_CRC_H_INCLUDED_ */