1 files changed, 75 insertions, 0 deletions
diff --git a/deps/zlib/adler32.c b/deps/zlib/adler32.c
new file mode 100644
index 0000000..cccb3a2
--- /dev/null
+++ b/deps/zlib/adler32.c
@@ -0,0 +1,75 @@
+/* adler32.c -- compute the Adler-32 checksum of a data stream
+ * Copyright (C) 1995-2003 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+/* @(#) $Id$ */
+
+#define ZLIB_INTERNAL
+#include <stdint.h>
+#include <stddef.h>
+#include "zutil.h"
+
+#define BASE 65521UL    /* largest prime smaller than 65536 */
+#define NMAX 5552
+/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
+
+#define DO1(buf,i)  {s1 += buf[i]; s2 += s1;}
+#define DO2(buf,i)  DO1(buf,i); DO1(buf,i+1);
+#define DO4(buf,i)  DO2(buf,i); DO2(buf,i+2);
+#define DO8(buf,i)  DO4(buf,i); DO4(buf,i+4);
+#define DO16(buf)   DO8(buf,0); DO8(buf,8);
+
+#ifdef NO_DIVIDE
+#  define MOD(a) \
+   do { \
+      if (a >= (BASE << 16)) a -= (BASE << 16); \
+      if (a >= (BASE << 15)) a -= (BASE << 15); \
+      if (a >= (BASE << 14)) a -= (BASE << 14); \
+      if (a >= (BASE << 13)) a -= (BASE << 13); \
+      if (a >= (BASE << 12)) a -= (BASE << 12); \
+      if (a >= (BASE << 11)) a -= (BASE << 11); \
+      if (a >= (BASE << 10)) a -= (BASE << 10); \
+      if (a >= (BASE << 9)) a -= (BASE << 9); \
+      if (a >= (BASE << 8)) a -= (BASE << 8); \
+      if (a >= (BASE << 7)) a -= (BASE << 7); \
+      if (a >= (BASE << 6)) a -= (BASE << 6); \
+      if (a >= (BASE << 5)) a -= (BASE << 5); \
+      if (a >= (BASE << 4)) a -= (BASE << 4); \
+      if (a >= (BASE << 3)) a -= (BASE << 3); \
+      if (a >= (BASE << 2)) a -= (BASE << 2); \
+      if (a >= (BASE << 1)) a -= (BASE << 1); \
+      if (a >= BASE) a -= BASE; \
+   } while (0)
+#else
+#  define MOD(a) a %= BASE
+#endif
+
+/* ========================================================================= */
+uLong adler32(uLong adler, const Bytef *buf, uInt len)
+{
+   uint32_t s1 = adler & 0xffff;
+   uint32_t s2 = (adler >> 16) & 0xffff;
+   int k;
+
+   if (buf == NULL)
+      return 1L;
+
+   while (len > 0) {
+      k = len < NMAX ? (int)len : NMAX;
+      len -= k;
+      while (k >= 16) {
+         DO16(buf);
+         buf += 16;
+         k -= 16;
+      }
+      if (k != 0) do {
+         s1 += *buf++;
+         s2 += s1;
+      } while (--k);
+      MOD(s1);
+      MOD(s2);
+   }
+   return (s2 << 16) | s1;
+}
+