refactor and xargs

1 files changed, 54 insertions, 70 deletions

diff --git a/src/commands/head.c b/src/commands/head.c
index 018da5a..44bc45b 100644
--- a/src/commands/head.c
+++ b/src/commands/head.c
@@ -1,17 +1,17 @@
 #include "../command.h"
 
-struct Flags {
+static struct {
     int count;
     bool lines;
     bool print_headers;
     bool dont_print_headers;
-};
+} flags;
 
-static void head_file_lines(FILE* file, struct Flags* flags) {
+static void head_file_lines(FILE* file) {
     size_t len = 0;
     char* line = NULL;
 
-    int count = flags->count;
+    int count = flags.count;
     while(count > 0 && getline(&line, &len, file) != -1) {
         printf("%s", line);
         count--;
@@ -21,9 +21,9 @@ static void head_file_lines(FILE* file, struct Flags* flags) {
     fclose(file);
 }
 
-static void head_file_chars(FILE* file, struct Flags* flags) {
+static void head_file_chars(FILE* file) {
     char c;
-    int count = flags->count;
+    int count = flags.count;
     while(count > 0 && (c = getc(file)) != EOF) {
         putchar(c);
         count--;
@@ -32,7 +32,7 @@ static void head_file_chars(FILE* file, struct Flags* flags) {
     fclose(file);
 }
 
-static void help() {
+static void help(void) {
     printf("Usage: head [OPTIONS] [FILE]...\n\n");
     printf("Print first 10 lines of FILEs (or stdin)\n");
     printf("With more than one FILE, precede each with a filename header.\n\n");
@@ -41,19 +41,11 @@ static void help() {
 	printf("\t\t\t(b:*512 k:*1024 m:*1024^2)\n");
 	printf("\t-q\t\tNever print headers\n");
 	printf("\t-v\t\tAlways print headers\n");
-    exit(EXIT_SUCCESS);
 }
 
-static char* next_arg(int argc, char** argv, int index) {
-    if (index >= argc) {
-        error("error: expected another argument after option");
-    }
-    return argv[index];
-}
-
-static void print_header(char* path, struct Flags* flags, bool many) {
-    if (flags->dont_print_headers) return;
-    if (!many && !flags->print_headers) return;
+static void print_header(char* path, bool many) {
+    if (flags.dont_print_headers) return;
+    if (!many && !flags.print_headers) return;
     if (streql("-", path)) {
         printf("\n==> standard input <==\n");
     } else {
@@ -61,81 +53,73 @@ static void print_header(char* path, struct Flags* flags, bool many) {
     }
 }
 
-static void head_file(char* path, struct Flags* flags, bool many) {
+static void head_file(char* path, bool many) {
     FILE* file = get_file(path, "r");
-    print_header(path, flags, many);
-    if (flags->lines) {
-        head_file_lines(file, flags);
+    print_header(path, many);
+    if (flags.lines) {
+        head_file_lines(file);
     } else {
-        head_file_chars(file, flags);
+        head_file_chars(file);
+    }
+}
+
+static int short_arg(char c, char* next) {
+    switch(c) {
+        case 'c': {
+            flags.lines = false;
+            check_arg(next);
+            long int bkm = get_blkm(next);
+            if (bkm < 1) {
+                error("error: bkm cannot be less than 1");
+            }
+            flags.count = bkm;
+            return ARG_USED;
+        }
+        case 'n': {
+            flags.lines = true;
+            check_arg(next);
+            long int bkm = get_blkm(next);
+            if (bkm < 1) {
+                error("error: bkm cannot be less than 1");
+            }
+            flags.count = bkm;
+            return ARG_USED;
+        }
+        case 'q':
+            flags.dont_print_headers = true;
+            break;
+        case 'v':
+            flags.print_headers = true;
+            break;
+        default: {
+            error("error: unknown option -%c", c);
+        }
     }
+    return ARG_UNUSED;
 }
 
 COMMAND(head) {
-    struct Flags flags;
     flags.count = 10;
     flags.lines = true;
     flags.print_headers = false;
     flags.dont_print_headers = false;
 
-    int start = 0;
-    for (int i = 0; i < argc; i++) { 
-        if (!prefix("-", argv[i])) break;
-        if (streql(argv[0], "--help")) help();
-        start++;
-        int i_s = i;
-        for (size_t j = 1; j < strlen(argv[i_s]); j++) {
-            char c = argv[i_s][j];
-            switch(c) {
-                case 'c': {
-                    start++;
-                    flags.lines = false;
-                    char* arg = next_arg(argc, argv, ++i);
-                    long int bkm = get_blkm(arg);
-                    if (bkm < 1) {
-                        error("error: bkm cannot be less than 1");
-                    }
-                    flags.count = bkm;
-                    break;
-                }
-                case 'n': {
-                    start++;
-                    flags.lines = true;
-                    char* arg = next_arg(argc, argv, ++i);
-                    long int bkm = get_blkm(arg);
-                    if (bkm < 1) {
-                        error("error: bkm cannot be less than 1");
-                    }
-                    flags.count = bkm;
-                    break;
-                }
-                case 'q':
-                    flags.dont_print_headers = true;
-                    break;
-                case 'v':
-                    flags.print_headers = true;
-                    break;
-                default: {
-                    error("error: unknown option -%c", c);
-                }
-            }
-        }
-    }
+    int start = parse_args(argc, argv, help, short_arg, NULL);
 
     int count = argc - start;
 
     if (count < 1) {
-        head_file_lines(stdin, &flags);
+        head_file_lines(stdin);
         return EXIT_SUCCESS;
     }
 
     if (count == 1) {
-        head_file(argv[start], &flags, false);
+        head_file(argv[start], false);
         return EXIT_SUCCESS;
     }
 
     for (int i = 0; i < count; i++) {
-        head_file(argv[start + i], &flags, true);
+        head_file(argv[start + i], true);
     }
 
     return EXIT_SUCCESS;