utils-std

commit: 72625f923bf81fb977264cecb90ac8c0c86d8a94
parent efb556f123a37119d65cf0d3d9dadd2c24d41905
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Tue, 30 Jul 2024 04:37:52 +0200

cmd/echo: simplify via editing argv in place

Diffstat:
M
cmd/echo.c
58
+++++++++++++++++-----------------------------------------

1 file changed, 17 insertions(+), 41 deletions(-)
diff --git a/cmd/echo.c b/cmd/echo.c
@@ -3,31 +3,34 @@
 // SPDX-License-Identifier: MPL-2.0
 
 #define _POSIX_C_SOURCE 200809L
-#include <errno.h>
 #include <stdbool.h>
-#include <stdio.h>  // fprintf
-#include <stdlib.h> // malloc
-#include <string.h> // strerror, strlen
+#include <stdio.h>  // perror
+#include <string.h> // strlen
 #include <unistd.h> // write
 
 int
 main(int argc, char *argv[])
 {
 	size_t arg_len = 0;
-	char *buffer, *buffer_p;
-	int err = 0;
 	bool opt_n = false;
 
-	if((argc >= 2) && (strncmp(argv[1], "-n", 3) == 0))
+	argc--;
+	argv++;
+
+	if(argc > 0 && strncmp(*argv, "-n", 3) == 0)
 	{
 		opt_n = true;
 		argc--;
 		argv++;
 	}
 
-	for(int i = 1; i < argc; i++)
+	for(int i = 0; i < argc; i++)
 	{
-		arg_len += strlen(argv[i]) + 1; // str + space|newline
+		size_t len = strlen(argv[i]);
+
+		if(len > 0) argv[i][len] = (i + 1) == argc ? '\n' : ' ';
+
+		arg_len += len + 1; // str + space|newline
 	}
 
 	if(arg_len == 0)
@@ -36,7 +39,7 @@ main(int argc, char *argv[])
 
 		if(write(1, "\n", 1) < 1)
 		{
-			fprintf(stderr, "echo: Write error: %s\n", strerror(errno));
+			perror("echo: Write error");
 			return 1;
 		}
 
@@ -45,39 +48,12 @@ main(int argc, char *argv[])
 
 	if(opt_n) arg_len--; // no newline
 
-	buffer = malloc(arg_len);
-	if(buffer == NULL)
-	{
-		fprintf(stderr, "echo: Memory allocation error, malloc(%zu): %s\n", arg_len, strerror(errno));
-		return 1;
-	}
-
-	buffer_p = buffer;
-	for(int i = 1; i < argc; i++)
-	{
-		size_t len = strlen(argv[i]);
-		memcpy(buffer_p, argv[i], len);
-		buffer_p += len;
-
-		if(i < argc - 1)
-		{
-			*buffer_p++ = ' ';
-		}
-	}
-	if(!opt_n) *buffer_p++ = '\n';
-
-	ssize_t nwrite = write(1, buffer, arg_len);
+	ssize_t nwrite = write(1, *argv, arg_len);
 	if(nwrite < (ssize_t)arg_len)
 	{
-		fprintf(stderr,
-		        "echo: Write error, write(1, buffer, %zu) = %zd: %s\n",
-		        arg_len,
-		        nwrite,
-		        strerror(errno));
-		err++;
+		perror("echo: Write error");
+		return 1;
 	}
 
-	free(buffer);
-
-	return err;
+	return 0;
 }