Better adler32.

1 files changed, 4 insertions, 3 deletions

diff --git a/lib/deflate.c b/lib/deflate.c
index 06d61e97..a418c21c 100644
--- a/lib/deflate.c
+++ b/lib/deflate.c
@@ -433,16 +433,17 @@ static void gzip_crc(struct deflate *dd, char *data, unsigned len)
 
 /*
 // Start with crc = 1, or pass in last crc to append more data
+// Deferred modulus good for paged size inputs (can't overflow for ~5500 bytes)
 unsigned adler32(char *buf, unsigned len, unsigned crc)
 {
   unsigned aa = crc&((1<<16)-1), bb = crc>>16;
 
   while (len--) {
-    aa = (aa+*buf)%65521;
-    bb = (bb+aa)%65521;
+    aa += *buf++;
+    bb += aa;
   }
 
-  return (bb<16)+aa;
+  return ((bb%65521)<<16)+aa%65521;
 }
 */