X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/rigol/blobdiff_plain/e8e713c3a536c59f94d6402d852f353e34fac2de..7df76f49adf30ac260c99649678b084c9b6c282b:/png.c

diff --git a/png.c b/png.c
index 7606f2b..ac09767 100644
--- a/png.c
+++ b/png.c
@@ -68,7 +68,7 @@ unsigned char *lcd2png(unsigned char *lcd, int *len)
 	unsigned char lut[256][3];
 	unsigned char *screen_deflated;
 	int deflated_size;
-	unsigned char *image;
+	unsigned char *image = NULL;
 	unsigned char *outpos;
 	static const unsigned char png[] = {137, 80, 78, 71, 13, 10, 26, 10};
 	static unsigned char idat[] = {'I', 'D', 'A', 'T'};
@@ -117,6 +117,7 @@ unsigned char *lcd2png(unsigned char *lcd, int *len)
 	strm.next_in = screen_conv;
 
 	toalloc = 0;
+	strm.avail_out = 0;
 	screen_deflated = NULL;
 	flush = Z_NO_FLUSH;
 
@@ -147,7 +148,6 @@ unsigned char *lcd2png(unsigned char *lcd, int *len)
 
 	deflateEnd(&strm);
 
-
 	image = malloc(sizeof(png) +
 		sizeof(ihdr) + 8 + /* 8 = length, csum */
 		sizeof(idat) + deflated_size + 8 +
@@ -155,12 +155,16 @@ unsigned char *lcd2png(unsigned char *lcd, int *len)
 	
 	if (image == NULL) {
 		perror("malloc");
+		return NULL;
 	}
 	
 	outpos = image;
+
+	/* PNG signature */
 	memcpy(outpos, png, sizeof(png));
 	outpos += sizeof(png);
 
+	/* IHDR */
 	l = htonl(sizeof(ihdr) - 4); /* "IHDR" is not counted */
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);
@@ -170,6 +174,7 @@ unsigned char *lcd2png(unsigned char *lcd, int *len)
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);
 
+	/* IDAT */
 	l = htonl(deflated_size);
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);
@@ -182,6 +187,7 @@ unsigned char *lcd2png(unsigned char *lcd, int *len)
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);
 
+	/* IEND */
 	l = htonl(sizeof(iend) - 4); /* "IEND" is not counted */
 	memcpy(outpos, &l, sizeof(l));
 	outpos += sizeof(l);