flate

commit bc3229678243ab7844b5e6d8c9ac7ef348aed039
parent 76b3cac7919f6ea0663abb27e104a7c7a4235f56
Author: nsz <nszabolcs@gmail.com>
Date:   Fri, 21 Aug 2009 15:27:33 +0200

fix gzip checksum byte order
Diffstat:
sflate.c
 | 
27
+++++++++++++--------------

1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/sflate.c b/sflate.c
@@ -3,10 +3,6 @@
 #include <string.h>
 #include "flate.h"
 
-static int checkfooter(uchar *p, uint sum) {
-	return sum == ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
-}
-
 enum {
 	ZlibCM    = 7 << 4,
 	ZlibCINFO = 8,
@@ -46,7 +42,8 @@ int inflate_zlib_header(uchar *p, int n) {
 }
 
 int inflate_zlib_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
-	if (n < 4 || !checkfooter(p, sum))
+	if (n < 4 ||
+	    sum != ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]))
 		return FlateErr;
 	return 4;
 }
@@ -82,14 +79,14 @@ int deflate_gzip_header(uchar *p, int n) {
 int deflate_gzip_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
 	if (n < 8)
 		return FlateErr;
-	p[0] = sum >> 24;
-	p[1] = sum >> 16;
-	p[2] = sum >> 8;
-	p[3] = sum;
-	p[4] = len >> 24;
-	p[5] = len >> 16;
-	p[6] = len >> 8;
-	p[7] = len;
+	p[0] = sum;
+	p[1] = sum >> 8;
+	p[2] = sum >> 16;
+	p[3] = sum >> 24;
+	p[4] = len;
+	p[5] = len >> 8;
+	p[6] = len >> 16;
+	p[7] = len >> 24;
 	return 8;
 }
 
@@ -130,7 +127,9 @@ int inflate_gzip_header(uchar *p, int n) {
 }
 
 int inflate_gzip_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
-	if (n < 8 || !checkfooter(p, sum) || !checkfooter(p+4, len))
+	if (n < 8 ||
+	    sum != (p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24)) ||
+	    len != (p[4] | (p[5] << 8) | (p[6] << 16) | (p[7] << 24)))
 		return FlateErr;
 	return 8;
 }