Use a header structure for reading / writing the header.

Author: Sam Price

bscommon.h

@@ -0,0 +1,12 @@
+#ifndef BS_COMMON_H
+#define BS_COMMON_H
+
+# include <stdint.h>
+
+#define HEADER_TXT ("ENDSLEY/BSDIFF43")
+typedef struct BSHeader{
+	char header_txt[sizeof(HEADER_TXT)];
+	uint8_t new_size[8];
+}BSHeader;
+
+#endif

bsdiff.c

@@ -26,7 +26,7 @@
  */
 
 #include "bsdiff.h"
-
+#include "bscommon.h"
 #include <limits.h>
 #include <string.h>
 
@@ -379,7 +379,7 @@ int main(int argc,char *argv[])
 	int bz2err;
 	uint8_t *old,*new;
 	off_t oldsize,newsize;
-	uint8_t buf[8];
+	BSHeader header;
 	FILE * pf;
 	struct bsdiff_stream stream;
 	BZFILE* bz2;
@@ -415,12 +415,11 @@ int main(int argc,char *argv[])
 		err(1, "%s", argv[3]);
 
 	/* Write header (signature+newsize)*/
-	offtout(newsize, buf);
-	if (fwrite("ENDSLEY/BSDIFF43", 16, 1, pf) != 1 ||
-		fwrite(buf, sizeof(buf), 1, pf) != 1)
+	strncpy(header.header_txt,HEADER_TXT, sizeof(header.header_txt));
+	offtout(newsize, header.new_size);
+	if(	fwrite(&header,sizeof(header),1,pf) != 1)
 		err(1, "Failed to write header");
 
-
 	if (NULL == (bz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)))
 		errx(1, "BZ2_bzWriteOpen, bz2err=%d", bz2err);
 

bspatch.c

@@ -106,7 +106,7 @@ int bspatch(const uint8_t* old, int64_t oldsize, uint8_t* new, int64_t newsize,
 #include <sys/stat.h>
 #include <unistd.h>
 #include <fcntl.h>
-
+#include "bscommon.h"
 static int bz2_read(const struct bspatch_stream* stream, void* buffer, int length)
 {
 	int n;
@@ -126,7 +126,7 @@ int main(int argc,char * argv[])
 	FILE * f;
 	int fd;
 	int bz2err;
-	uint8_t header[24];
+	BSHeader header;
 	uint8_t *old, *new;
 	int64_t oldsize, newsize;
 	BZFILE* bz2;
@@ -140,18 +140,18 @@ int main(int argc,char * argv[])
 		err(1, "fopen(%s)", argv[3]);
 
 	/* Read header */
-	if (fread(header, 1, 24, f) != 24) {
+	if (fread(&header, sizeof(header), 1 , f) != 1) {
 		if (feof(f))
 			errx(1, "Corrupt patch\n");
 		err(1, "fread(%s)", argv[3]);
 	}
 
 	/* Check for appropriate magic */
-	if (memcmp(header, "ENDSLEY/BSDIFF43", 16) != 0)
+	if (memcmp(header.header_txt, HEADER_TXT, sizeof(HEADER_TXT)) != 0)
 		errx(1, "Corrupt patch\n");
 
 	/* Read lengths from header */
-	newsize=offtin(header+16);
+	newsize=offtin(header.new_size);
 	if(newsize<0)
 		errx(1,"Corrupt patch\n");