1 files changed, 56 insertions, 0 deletions
diff --git a/Build/source/extra/unzip/crc32.c b/Build/source/extra/unzip/crc32.c
new file mode 100644
index 00000000000..ff2daa0c088
--- /dev/null
+++ b/Build/source/extra/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 */