From ef35b890c16c9f2d3aff29ce8562a3323aeb3a43 Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Thu, 16 Jun 2022 22:48:07 +0200
Subject: Streamlined error handling in head

---
 head.c | 62 +++++++++++++++++++++++++++-----------------------------------
 1 file changed, 27 insertions(+), 35 deletions(-)

diff --git a/head.c b/head.c
index d5165e4..f4deca2 100644
--- a/head.c
+++ b/head.c
@@ -5,16 +5,14 @@
 #include <unistd.h>
 
 
-int head(int fd, int lines, const char * name)
+int head(const int fd, int lines)
 {
 	static const size_t SIZE = 1024 * 4;
 	char buffer[SIZE];
-	while (lines > 0) {
+	while (0 < lines) {
 		const ssize_t available = read(fd, buffer, SIZE);
-		if (-1 == available) {
-			perror(name);
+		if (-1 == available)
 			return 1;
-		}
 		if (0 == available)
 			return 0;
 		size_t offset = 0;
@@ -22,11 +20,9 @@ int head(int fd, int lines, const char * name)
 			if (buffer[n] == '\n') {
 				lines--;
 				if (0 <= lines) {
-					const ssize_t res = write(1, buffer + offset, 1 + n - offset);
-					if (-1 == res) {
-						perror(name);
+					const ssize_t result = write(1, buffer + offset, 1 + n - offset);
+					if (-1 == result)
 						return 1;
-					}
 					offset = 1 + n;
 				}
 				if (0 >= lines)
@@ -34,11 +30,9 @@ int head(int fd, int lines, const char * name)
 			}
 		}
 		if (0 < lines) {
-			const ssize_t res = write(1, buffer + offset, available - offset);
-			if (-1 == res) {
-				perror(name);
+			const ssize_t result = write(1, buffer + offset, available - offset);
+			if (-1 == result)
 				return 1;
-			}
 		}
 	}
 	return 0;
@@ -49,7 +43,7 @@ int main(int argc, char * argv[])
 {
 	int opt;
 	int lines = 10;
-	while (-1 != (opt = getopt(argc, argv, "n:"))) {
+	while (-1 != (opt=getopt(argc, argv, "n:"))) {
 		switch (opt) {
 		case 'n':
 			errno = 0;
@@ -66,28 +60,26 @@ int main(int argc, char * argv[])
 			return 1;
 		}
 	}
-	const unsigned int file_count = argc - optind;
-	int res = 0;
-	if (optind >= argc)
-		res |= head(0, lines, "-");
-	else for (int i = optind; i < argc; ++i) {
-		if (1 < file_count)
-			printf("==> %s <==\n", argv[i]);
-		const unsigned int is_stdin = '-' == argv[i][0] && 0 == argv[i][1];
-		const int fd = is_stdin ? 0 : open(argv[i], O_RDONLY);
-		if (-1 == fd) {
-			perror(argv[i]);
-			res = 1;
-			continue;
+	const int files_count = argc - optind;
+	int i = optind;
+	int overall = 0;
+	do {
+		const char * const path = argc == i ? "-" : argv[i];
+		const unsigned int is_stdin = '-' == path[0] && 0 == path[1];
+		const int fd = is_stdin ? 0 : open(path, O_RDONLY);
+		if (1 < files_count)
+			printf(optind == i ? "==> %s <==\n" : "\n==> %s <==\n", path);
+		if (0 <= fd) {
+			const int result = head(fd, lines) | is_stdin ? 0 : close(fd);
+			if (0 != result)
+				perror(path);
+			overall |= result;
 		}
-		res |= head(fd, lines, argv[i]);
-		if (!is_stdin) {
-			const int clr = close(fd);
-			if (-1 == clr) {
-				perror(argv[i]);
-				res = 1;
-			}
+		else {
+			perror(path);
+			overall = 1;
 		}
 	}
-	return res;
+	while (++i < argc);
+	return overall;
 }
-- 
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