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Annotation of embedaddon/nginx/src/core/ngx_crc.h, revision 1.1

1.1     ! misho       1: 
        !             2: /*
        !             3:  * Copyright (C) Igor Sysoev
        !             4:  * Copyright (C) Nginx, Inc.
        !             5:  */
        !             6: 
        !             7: 
        !             8: #ifndef _NGX_CRC_H_INCLUDED_
        !             9: #define _NGX_CRC_H_INCLUDED_
        !            10: 
        !            11: 
        !            12: #include <ngx_config.h>
        !            13: #include <ngx_core.h>
        !            14: 
        !            15: 
        !            16: /* 32-bit crc16 */
        !            17: 
        !            18: static ngx_inline uint32_t
        !            19: ngx_crc(u_char *data, size_t len)
        !            20: {
        !            21:     uint32_t  sum;
        !            22: 
        !            23:     for (sum = 0; len; len--) {
        !            24: 
        !            25:         /*
        !            26:          * gcc 2.95.2 x86 and icc 7.1.006 compile
        !            27:          * that operator into the single "rol" opcode,
        !            28:          * msvc 6.0sp2 compiles it into four opcodes.
        !            29:          */
        !            30:         sum = sum >> 1 | sum << 31;
        !            31: 
        !            32:         sum += *data++;
        !            33:     }
        !            34: 
        !            35:     return sum;
        !            36: }
        !            37: 
        !            38: 
        !            39: #endif /* _NGX_CRC_H_INCLUDED_ */