findhex

commit fda2cdb74759d14a9c9c0644fb6e5bd2505e2639
parent 8fde78de2cf95793fe4aed00b899aca2695164b6
Author: Louis Burda <quent.burda@gmail.com>
Date:   Wed, 15 Feb 2023 19:11:53 +0100

Error handling with err() and simplified program

Diffstat:
M
Makefile
 | 
1
+
M
findhex.c
 | 
61
+++++++++++++++++++++++++++++--------------------------------

2 files changed, 30 insertions(+), 32 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,3 +1,4 @@
+CFLAGS = -Wunused-variable -Wunused-function
 
 all: findhex
 
diff --git a/findhex.c b/findhex.c
@@ -1,22 +1,8 @@
-#include <stdlib.h>
-#include <stdio.h>
+#include <err.h>
 #include <string.h>
 #include <stdint.h>
-#include <stdarg.h>
-
-#define MAX(a, b) ((a) > (b) ? (a) : (b))
-
-void
-die(const char *msg, ...)
-{
-	va_list ap;
-
-	va_start(ap, msg);
-	vfprintf(stderr, "%s\n", ap);
-	va_end(ap);
-
-	exit(1);
-}
+#include <stdio.h>
+#include <stdlib.h>
 
 int
 main(int argc, const char **argv)
@@ -33,32 +19,44 @@ main(int argc, const char **argv)
 
 	setvbuf(stdout, NULL, _IONBF, 0);
 
-	if (argc < 2 || argc > 3) die("Usage: findhex PATTERN [FILE]");
+	if (argc < 2 || argc > 3) {
+		printf("Usage: findhex PATTERN [FILE]\n");
+		return 0;
+	}
 
 	arglen = strlen(argv[1]);
-	if (!arglen || arglen % 2 != 0)
-		die("Pattern length invalid");
+	if (!arglen || arglen % 2 != 0) {
+		fprintf(stderr, "Pattern length invalid\n");
+		return 1;
+	}
 	patlen = arglen / 2;
 
-	pattern = calloc(patlen, 1);
-	pattern_mask = calloc(patlen, 1);
-	if (!pattern || !pattern_mask) die("Out of Memory");
+	pattern = malloc(patlen);
+	if (!pattern) err(1, "malloc");
+
+	pattern_mask = malloc(patlen);
+	if (!pattern_mask) err(1, "malloc");
+
+	buflen = 16 * 1024;
+	if (patlen * 2 > buflen)
+		buflen = patlen * 2;
 
-	buflen = MAX(patlen * 2, 16 * 1024);
 	buf = malloc(buflen);
-	if (!buf) die("Out of Memory");
+	if (!buf) err(1, "malloc");
 
 	for (i = 0; i < arglen; i += 2) {
 		if (!strncmp(argv[1] + i, "__", 2))
 			continue;
-		if (!sscanf(argv[1] + i, "%02hX", &pattern[i / 2]))
-			die("Invalid hex in pattern");
+		if (!sscanf(argv[1] + i, "%02hhx", &pattern[i / 2])) {
+			fprintf(stderr, "Invalid hex in pattern\n");
+			return 1;
+		}
 		pattern_mask[i / 2] = 0xff;
 	}
 
 	if (argc == 3) {
-		file = fopen(argv[1], "r");
-		if (!file) die("Failed to open file");
+		file = fopen(argv[2], "r");
+		if (!file) err(1, "fopen");
 	} else {
 		file = stdin;
 	}
@@ -70,8 +68,7 @@ main(int argc, const char **argv)
 	pos = 0;
 	while (1) {
 		nread = fread(buf + off, 1, buflen - off, file);
-		if (nread == 0) break;
-		if (nread < 0) die("%016llX: Read failed", pos);
+		if (nread <= 0) break;
 
 		for (i = 0; i <= nread + off - patlen; i++) {
 			for (k = 0; k < patlen; k++) {
@@ -81,7 +78,7 @@ main(int argc, const char **argv)
 					break;
 			}
 			if (k == patlen)
-				printf("%016llX\n", pos + i);
+				printf("%016lX\n", pos + i);
 		}
 
 		pos += nread;