Improve command line interface.

source/commandline.cpp

@@ -0,0 +1,61 @@
+#include "commandline.h"
+
+std::map<char*, char*, compare_strings> cmd_get_args(int argc, char* argv[]) {
+    std::map<char*, char*, compare_strings> args;
+    for(int i = 0; i < argc; i++) {
+        if((strncmp(argv[i], "-", 1) == 0 || strncmp(argv[i], "--", 2) == 0) && argc != i + 1) {
+            args.insert(std::pair<char*, char*>(argv[i], argv[i + 1]));
+            i++;
+        }
+    }
+
+    return args;
+}
+
+char* cmd_find_arg(std::map<char*, char*, compare_strings> args, const char* shortOpt, const char* longOpt) {
+    char sopt[strlen(shortOpt) + 2];
+    sprintf(sopt, "-%s", shortOpt);
+    char lopt[strlen(longOpt) + 3];
+    sprintf(lopt, "--%s", longOpt);
+
+    std::map<char*, char*, compare_strings>::iterator match = args.find(sopt);
+    if(match != args.end()) {
+        return (*match).second;
+    }
+
+    match = args.find(lopt);
+    if(match != args.end()) {
+        return (*match).second;
+    }
+
+    return NULL;
+}
+
+void cmd_print_usage(const char* executedFrom) {
+    printf("Usage: %s <command> <args>\n", executedFrom);
+    cmd_print_commands();
+}
+
+void cmd_print_info(const char* command) {
+    if(strcmp(command, "makebanner") == 0) {
+        printf("makebanner - Creates a .bnr file.\n");
+        printf("  -i/--image: PNG file to use as the banner image.\n");
+        printf("  -a/--audio: Audio file to use as the banner's tune.\n");
+        printf("  -o/--output: File to output the created banner to.\n");
+    }
+}
+
+void cmd_print_commands() {
+    printf("Available commands:\n");
+    cmd_print_info("makebanner");
+}
+
+void cmd_missing_args(const char* command) {
+    printf("Missing arguments for command \"%s\".\n", command);
+    cmd_print_info(command);
+}
+
+void cmd_invalid_command(const char* command) {
+    printf("Invalid command \"%s\".\n", command);
+    cmd_print_commands();
+}