diff options
Diffstat (limited to 'app/nginx/src/core/ngx_crc.h')
-rw-r--r-- | app/nginx/src/core/ngx_crc.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/app/nginx/src/core/ngx_crc.h b/app/nginx/src/core/ngx_crc.h new file mode 100644 index 0000000..35981bc --- /dev/null +++ b/app/nginx/src/core/ngx_crc.h @@ -0,0 +1,39 @@ + +/* + * Copyright (C) Igor Sysoev + * Copyright (C) Nginx, Inc. + */ + + +#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_ */ |