summaryrefslogtreecommitdiff
path: root/Build/source/libs/unzip/crc32.c
diff options
context:
space:
mode:
Diffstat (limited to 'Build/source/libs/unzip/crc32.c')
-rw-r--r--Build/source/libs/unzip/crc32.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/Build/source/libs/unzip/crc32.c b/Build/source/libs/unzip/crc32.c
new file mode 100644
index 00000000000..ff2daa0c088
--- /dev/null
+++ b/Build/source/libs/unzip/crc32.c
@@ -0,0 +1,56 @@
+/* crc32.c -- compute the CRC-32 of a data stream
+ * Copyright (C) 1995 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+/* $Id: crc32.c,v 1.1 1999/02/01 04:22:50 mik Exp $ */
+
+#define __CRC32_C /* identifies this source module */
+
+#include "zip.h"
+
+#ifndef USE_ZLIB
+#ifndef ASM_CRC
+
+#ifndef ZCONST
+# define ZCONST const
+#endif
+
+#ifdef CRC32
+# undef CRC32
+#endif
+#define CRC32(c, b) (crc_table[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8))
+#define DO1(buf) crc = CRC32(crc, *buf++)
+#define DO2(buf) DO1(buf); DO1(buf)
+#define DO4(buf) DO2(buf); DO2(buf)
+#define DO8(buf) DO4(buf); DO4(buf)
+
+/* ========================================================================= */
+ulg crc32(crc, buf, len)
+ register ulg crc; /* crc shift register */
+ register ZCONST uch *buf; /* pointer to bytes to pump through */
+ extent len; /* number of bytes in buf[] */
+/* Run a set of bytes through the crc shift register. If buf is a NULL
+ pointer, then initialize the crc shift register contents instead.
+ Return the current crc in either case. */
+{
+ register ZCONST ulg near *crc_table;
+
+ if (buf == NULL) return 0L;
+
+ crc_table = get_crc_table();
+
+ crc = crc ^ 0xffffffffL;
+#ifndef NO_UNROLLED_LOOPS
+ while (len >= 8) {
+ DO8(buf);
+ len -= 8;
+ }
+#endif
+ if (len) do {
+ DO1(buf);
+ } while (--len);
+ return crc ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
+}
+#endif /* !ASM_CRC */
+#endif /* !USE_ZLIB */