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src/core/ngx_crc.h - nginx-1.7.10

Functions defined

Macros defined

Source code


  2. /*
  3. * Copyright (C) Igor Sysoev
  4. * Copyright (C) Nginx, Inc.
  5. */


  8. #ifndef _NGX_CRC_H_INCLUDED_
  9. ‌#define _NGX_CRC_H_INCLUDED_


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


  16. /* 32-bit crc16 */

  18. static ngx_inline uint32_t
  19. ‌ngx_crc(u_char *data, size_t len)
  20. {
  21.     uint32_t  sum;

  23.     for (sum = 0; len; len--) {

  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;

  32.         sum += *data++;
  33.     }

  35.     return sum;
  36. }


  39. #endif /* _NGX_CRC_H_INCLUDED_ */

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