initial commit

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_ */