Improve error-handling in the tools

We don't need the jumps, but rather pass a nice function pointer to
libpng. The jump in libjpg was also useless.
We check each fwrite-call so there's an early bailout in case the output
file is full.
Flushing at the end worked as well, but it took too long for complex
images. We don't want to "block" a pipe here and the approach in jpg2ff
was better.
The iHDR-read was useless. Rather use the get*-functions in libpng,
saves us 2 local variables as well.

1 files changed, 22 insertions, 30 deletions

diff --git a/ff2png.c b/ff2png.c
index 62a00f2..a1276d7 100644
--- a/ff2png.c
+++ b/ff2png.c
@@ -2,7 +2,6 @@
 #include <arpa/inet.h>
 
 #include <errno.h>
-#include <setjmp.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -12,6 +11,15 @@
 
 #define HEADER "farbfeld########"
 
+static char *argv0;
+
+void
+pngerr(png_structp png_struct_p, png_const_charp msg)
+{
+	fprintf(stderr, "%s: libpng: %s\n", argv0, msg);
+	exit(1);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -19,38 +27,37 @@ main(int argc, char *argv[])
 	png_infop png_info_p;
 	png_size_t png_row_len, j;
 	png_uint_32 width, height, i;
-	int ret = 0;
 	uint16_t tmp16, *png_row;
 	uint8_t hdr[16];
 
-	if (argc > 1) {
-		fprintf(stderr, "usage: %s\n", argv[0]);
+	argv0 = argv[0], argc--, argv++;
+
+	if (argc) {
+		fprintf(stderr, "usage: %s\n", argv0);
 		return 1;
 	}
 
 	/* header */
 	if (fread(hdr, 1, strlen(HEADER), stdin) != strlen(HEADER)) {
-		fprintf(stderr, "%s: incomplete header\n", argv[0]);
+		fprintf(stderr, "%s: incomplete header\n", argv0);
 		return 1;
 	}
 	if (memcmp("farbfeld", hdr, strlen("farbfeld"))) {
-		fprintf(stderr, "%s: invalid magic value\n", argv[0]);
+		fprintf(stderr, "%s: invalid magic value\n", argv0);
 		return 1;
 	}
 	width = ntohl(*((uint32_t *)(hdr + 8)));
 	height = ntohl(*((uint32_t *)(hdr + 12)));
 
 	/* load png */
-	png_struct_p = png_create_write_struct(PNG_LIBPNG_VER_STRING,
-                                               NULL, NULL, NULL);
+	png_struct_p = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+	                                       pngerr, NULL);
 	png_info_p = png_create_info_struct(png_struct_p);
 
 	if (!png_struct_p || !png_info_p) {
-		fprintf(stderr, "%s: failed to initialize libpng\n", argv[0]);
+		fprintf(stderr, "%s: failed to initialize libpng\n", argv0);
 		return 1;
 	}
-	if (setjmp(png_jmpbuf(png_struct_p)))
-		return 1;
 	png_init_io(png_struct_p, stdout);
 	png_set_IHDR(png_struct_p, png_info_p, width, height, 16,
 	             PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
@@ -60,15 +67,13 @@ main(int argc, char *argv[])
 	/* write rows */
 	png_row_len = strlen("RGBA") * width * sizeof(uint16_t);
 	if (!(png_row = malloc(png_row_len))) {
-		fprintf(stderr, "%s: malloc: out of memory\n", argv[0]);
+		fprintf(stderr, "%s: malloc: out of memory\n", argv0);
 		return 1;
 	}
 	for (i = 0; i < height; ++i) {
 		for (j = 0; j < png_row_len / sizeof(uint16_t); ++j) {
-			if (fread(&tmp16, 1, sizeof(uint16_t), stdin) !=
-			    sizeof(uint16_t)) {
-				fprintf(stderr, "%s: unexpected EOF\n",
-				        argv[0]);
+			if (fread(&tmp16, sizeof(uint16_t), 1, stdin) != 1) {
+				fprintf(stderr, "%s: unexpected EOF\n", argv0);
 				return 1;
 			}
 			png_row[j] = tmp16;
@@ -76,20 +81,7 @@ main(int argc, char *argv[])
 		png_write_row(png_struct_p, (uint8_t *)png_row);
 	}
 	png_write_end(png_struct_p, NULL);
-
 	png_destroy_write_struct(&png_struct_p, NULL);
 
-	/* flush output */
-	if (fflush(stdout)) {
-		fprintf(stderr, "%s: fflush stdout: ", argv[0]);
-		perror(NULL);
-		ret = 1;
-	}
-	if (fclose(stdout) && !ret) {
-		fprintf(stderr, "%s: fclose stdout: ", argv[0]);
-		perror(NULL);
-		ret = 1;
-	}
-
-	return ret;
+	return 0;
 }