From c29cfeaa5c6ab5c7e0c39415fe3c9c103c8bdf64 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michael=20G=C3=B6hler?= <somebody.here@gmx.de>
Date: Sun, 17 Aug 2014 14:56:21 +0200
Subject: [PATCH] added getopts argument parsing + usage + debug mode

---
 .gdbinit |   2 +-
 tmp.c    | 103 ++++++++++++++++++++++++++++++++++++++-----------------
 2 files changed, 72 insertions(+), 33 deletions(-)

diff --git a/.gdbinit b/.gdbinit
index cd479e1..9733b15 100644
--- a/.gdbinit
+++ b/.gdbinit
@@ -1 +1 @@
-set args sample.md
+set args -d sample.md
diff --git a/tmp.c b/tmp.c
index 805cb3e..f2d7e32 100644
--- a/tmp.c
+++ b/tmp.c
@@ -1,22 +1,55 @@
+#include <errno.h>
+#include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <errno.h>
+#include <string.h>
 
 #include "include/markdown.h"
 
+void usage() {
+    fprintf(stderr, "Usage: tmp [OPTION]... [FILE]\n");
+    fprintf(stderr, "A command-line based markdown presentation tool.\n\n");
+    fprintf(stderr, "  -d, --debug   enable debug messages on STDERR\n");
+    fprintf(stderr, "  -h, --help    display this help and exit\n");
+    fprintf(stderr, "\nWith no FILE, or when FILE is -, read standard input.\n\n");
+    exit(EXIT_FAILURE);
+}
+
 int main(int argc, char *argv[]) {
 
-    FILE *input;
-    document_t *doc;
+    // define command-line options
+    struct option longopts[] = {
+        { "debug", no_argument, 0, 'd' },
+        { "help",  no_argument, 0, 'h' },
+        { 0, 0, 0, 0 }
+    };
 
-    if (argc > 1) {
-        if(!strcmp(argv[1], "-")) {
+    // parse command-line options
+    int opt, debug = 0;
+    while ((opt = getopt_long(argc, argv, ":dh", longopts, NULL)) != -1) {
+        switch(opt) {
+            case 'd': debug = 1; break;
+            case 'h': usage(); break;
+            case ':': fprintf(stderr, "%s: '%c' requires an argument\n", argv[0], optopt); usage(); break;
+            case '?':
+            default : fprintf(stderr, "%s: option '%c' is invalid\n", argv[0], optopt); usage(); break;
+        }
+    }
+
+    // open file or set input to STDIN
+    char *file;
+    FILE *input;
+    if (optind < argc) {
+        do {
+            file = argv[optind];
+        } while(++optind < argc);
+
+        if(!strcmp(file, "-")) {
             input = stdin;
         } else {
-            input = fopen(argv[1],"r");
+            input = fopen(file,"r");
             if(!input) {
-                fprintf(stderr, "Unable to open '%s': %s\n",
-                    argv[1], strerror(errno));
+                fprintf(stderr, "%s: %s: %s\n", argv[0], file, strerror(errno));
                 exit(EXIT_FAILURE);
             }
         }
@@ -24,35 +57,41 @@ int main(int argc, char *argv[]) {
         input = stdin;
     }
 
+    // load document object from input
+    document_t *doc;
     doc = markdown_load(input);
 
-    // test line/page load
-    int offset;
-    line_t *header;
-    if(doc->header) {
-        header = doc->header;
-        while(header &&
-              header->text->size > 0 &&
-              header->text->text[0] == '%') {
+    if(debug) {
+        // print header to STDERR
+        int offset;
+        line_t *header;
+        if(doc->header) {
+            header = doc->header;
+            while(header &&
+                header->text->size > 0 &&
+                header->text->text[0] == '%') {
 
-            offset = next_blank(header->text, 0) + 1;
-            printf("header: %s\n", &header->text->text[offset]);
-            header = header->next;
+                offset = next_blank(header->text, 0) + 1;
+                printf("header: %s\n", &header->text->text[offset]);
+                header = header->next;
+            }
         }
-    }
-    int cp = 0, cl = 0;
-    page_t *page = doc->page;
-    line_t *line;
-    while(page) {
-        cp++;
-        line = page->line;
-        cl = 0;
-        while(line) {
-            cl++;
-            line = line->next;
+
+        // print page/line count to STDERR
+        int cp = 0, cl = 0;
+        page_t *page = doc->page;
+        line_t *line;
+        while(page) {
+            cp++;
+            line = page->line;
+            cl = 0;
+            while(line) {
+                cl++;
+                line = line->next;
+            }
+            printf("page %i: %i lines\n", cp, cl);
+            page = page->next;
         }
-        printf("page %i: %i lines\n", cp, cl);
-        page = page->next;
     }
 }