refactor and xargs

1 files changed, 63 insertions, 79 deletions

diff --git a/src/commands/tail.c b/src/commands/tail.c
index 118a771..a611842 100644
--- a/src/commands/tail.c
+++ b/src/commands/tail.c
@@ -1,13 +1,13 @@
 #include "../command.h"
 
-struct Flags {
+static struct {
     bool lines;
     int count;
     bool print_headers;
     bool dont_print_headers;
     bool print_as_grow;
     int grow_wait;
-};
+} flags;
 
 static size_t tail_file_lines(FILE* file, unsigned int count, size_t skip) {
     char* ring[count];
@@ -83,7 +83,7 @@ static size_t tail_file_chars(FILE* file, unsigned int count, size_t skip) {
     return read;
 }
 
-static void help() {
+static void help(void) {
     printf("Usage: tail [OPTIONS] [FILE]...\n\n");
     printf("Print last 10 lines of FILEs (or stdin) to.\n");
     printf("With more than one FILE, precede each with a filename header.\n\n");
@@ -97,16 +97,9 @@ static void help() {
     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 {
@@ -114,26 +107,72 @@ static void print_header(char* path, struct Flags* flags, bool many) {
     }
 }
 
-static void tail_file(char* path, struct Flags* flags, bool many) {
+static void tail_file(char* path, bool many) {
     FILE* file = get_file(path, "r");
-    print_header(path, flags, many);
+    print_header(path, many);
     
     size_t skip = 0;
     while (true) {
-        if (flags->lines) {
-            skip = tail_file_lines(file, flags->count, skip);
+        if (flags.lines) {
+            skip = tail_file_lines(file, flags.count, skip);
         } else {
-            skip = tail_file_chars(file, flags->count, skip);
+            skip = tail_file_chars(file, flags.count, skip);
         }
-        if (!flags->print_as_grow) break;
-        sleep(flags->grow_wait);
+        if (!flags.print_as_grow) break;
+        sleep(flags.grow_wait);
         get_file(path, "r");
     };
 }
 
+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;
+        case 'f':
+            flags.print_as_grow = true;
+            break;
+        case 's': {
+            check_arg(next);
+            long int sec = get_number(next);
+            if (sec < 1) {
+                error("error: wait seconds cannot be less than 1");
+            }
+            flags.grow_wait = sec;
+            return ARG_USED;
+        }
+        default: {
+            error("error: unknown option -%c", c);
+        }
+    }
+    return ARG_UNUSED;
+}
+
 COMMAND(tail) {
 
-    struct Flags flags;
     flags.count = 10;
     flags.dont_print_headers = false;
     flags.print_headers = false;
@@ -141,62 +180,7 @@ COMMAND(tail) {
     flags.print_as_grow = false;
     flags.grow_wait = 10;
 
-    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;
-                case 'f':
-                    flags.print_as_grow = true;
-                    break;
-                case 's': {
-                    start++;
-                    char* arg = next_arg(argc, argv, ++i);
-                    long int sec = get_number(arg);
-                    if (sec < 1) {
-                        error("error: wait seconds cannot be less than 1");
-                    }
-                    flags.grow_wait = sec;
-                    break;
-                }
-                default: {
-                    error("error: unknown option -%c", c);
-                }
-            }
-        }
-    }
+    int start = parse_args(argc, argv, help, short_arg, NULL);
 
     int count = argc - start;
 
@@ -206,12 +190,12 @@ COMMAND(tail) {
     }
 
     if (count == 1) {
-        tail_file(argv[start], &flags, false);
+        tail_file(argv[start], false);
         return EXIT_SUCCESS;
     }
 
     for (int i = 0; i < count; i++) {
-        tail_file(argv[start + i], &flags, true);
+        tail_file(argv[start + i], true);
     }
 
     return EXIT_SUCCESS;