Add efread() and efwrite()

Given we have a util.c anyway it does not make any sense to duplicate
code here. This way, error handling and output is in one place and one
does not have to change things in multiple different files. This also
reduces code duplication by a lot.

It also solves an older bug where the error reporting was not on point:

   $ echo "farb" | ff2png
   ff2png: fread: Success

(It also lacked a newline)

Now it properly reports

   $ echo "farb" | ff2png
   ff2png: fread: Unexpected end of file

I also fixed some other minor details, for instance that all error
messages should begin with a capital letter.

1 files changed, 32 insertions, 17 deletions

diff --git a/util.c b/util.c
index f9cf33e..212f595 100644
--- a/util.c
+++ b/util.c
@@ -18,13 +18,10 @@ ff_read_header(uint32_t *width, uint32_t *height)
 {
 	uint32_t hdr[4];
 
-	if (fread(hdr, sizeof(*hdr), LEN(hdr), stdin) != LEN(hdr)) {
-		fprintf(stderr, "%s: fread: %s", argv0, strerror(errno));
-		exit(1);
-	}
+	efread(hdr, sizeof(*hdr), LEN(hdr), stdin);
 
 	if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
-		fprintf(stderr, "%s: invalid magic value\n", argv0);
+		fprintf(stderr, "%s: Invalid magic value\n", argv0);
 		exit(1);
 	}
 
@@ -40,16 +37,10 @@ ff_write_header(uint32_t width, uint32_t height)
 	fputs("farbfeld", stdout);
 
 	tmp = htonl(width);
-	if (fwrite(&tmp, sizeof(tmp), 1, stdout) != 1) {
-		fprintf(stderr, "%s: write: %s", argv0, strerror(errno));
-		exit(1);
-	}
+	efwrite(&tmp, sizeof(tmp), 1, stdout);
 
 	tmp = htonl(height);
-	if (fwrite(&tmp, sizeof(tmp), 1, stdout) != 1) {
-		fprintf(stderr, "%s: write: %s", argv0, strerror(errno));
-		exit(1);
-	}
+	efwrite(&tmp, sizeof(tmp), 1, stdout);
 }
 
 int
@@ -93,13 +84,13 @@ fshut(FILE *fp, const char *fname)
 	fflush(fp);
 
 	if (ferror(fp) && !ret) {
-		fprintf(stderr, "%s: ferror %s: %s\n", argv0, fname,
+		fprintf(stderr, "%s: ferror '%s': %s\n", argv0, fname,
 		        strerror(errno));
 		ret = 1;
 	}
 
 	if (fclose(fp) && !ret) {
-		fprintf(stderr, "%s: fclose %s: %s\n", argv0, fname,
+		fprintf(stderr, "%s: fclose '%s': %s\n", argv0, fname,
 		        strerror(errno));
 		ret = 1;
 	}
@@ -107,13 +98,37 @@ fshut(FILE *fp, const char *fname)
 	return ret;
 }
 
+void
+efread(void *p, size_t s, size_t n, FILE *f)
+{
+	if (fread(p, s, n, f) != n) {
+		if (ferror(f)) {
+			fprintf(stderr, "%s: fread: %s\n", argv0,
+			        strerror(errno));
+		} else {
+			fprintf(stderr, "%s: fread: Unexpected end of file\n",
+			        argv0);
+		}
+		exit(1);
+	}
+}
+
+void
+efwrite(const void *p, size_t s, size_t n, FILE *f)
+{
+	if (fwrite(p, s, n, f) != n) {
+		fprintf(stderr, "%s: fwrite: %s\n", argv0, strerror(errno));
+		exit(1);
+	}
+}
+
 void *
 ereallocarray(void *optr, size_t nmemb, size_t size)
 {
 	void *p;
 
 	if (!(p = reallocarray(optr, nmemb, size))) {
-		fprintf(stderr, "%s: reallocarray: out of memory\n", argv0);
+		fprintf(stderr, "%s: reallocarray: Out of memory\n", argv0);
 		exit(1);
 	}
 
@@ -128,7 +143,7 @@ estrtonum(const char *numstr, long long minval, long long maxval)
 
 	ll = strtonum(numstr, minval, maxval, &errstr);
 	if (errstr) {
-		fprintf(stderr, "%s: strtonum %s: %s\n", argv0, numstr, errstr);
+		fprintf(stderr, "%s: strtonum '%s': %s\n", argv0, numstr, errstr);
 		exit(1);
 	}