Added argument parser and set all logs to STDERR

utils.c

@@ -0,0 +1,75 @@
+#include "utils.h"
+
+#include <stdio.h>
+#include <stddef.h>
+#include <string.h>
+
+/*
+ * Macros
+ */
+#define MAX_CLI_ARGS    (20)
+
+/*
+ * Type definitions
+ */
+typedef struct {
+    const char *key;
+    char *value;
+} cli_arg_t;
+
+/*
+ * Data
+ */
+static cli_arg_t _cli_args[MAX_CLI_ARGS];
+
+/*
+ * Public API
+ */
+void print_usage_text() {
+    printf("ipoim -M <mode> -A <address> -P <port> -C <carrier> ...\n");
+    printf(" --- MANDATORY ARGUMENTS ---\n");
+    printf("    -M <mode>           - operation mode ('provider' or 'last-mile')\n");
+    printf("    -A <address>        - IPv4 to listen on/connect to\n");
+    printf("    -P <port>           - port to listen on/connect to\n");
+    printf("    -E <carrier>        - extension to use, one of:\n");
+    printf("        * pipe          - use STDIN and STDOUT\n");
+    printf(" --- OPTIONAL ARGUMENTS ---\n");
+    printf("    +V                  - be verbose\n");
+}
+
+bool cli_arg_set(const char *key, char *value) {
+    int index_to_use = -1;
+    for (int i = 0; i < MAX_CLI_ARGS; ++i) {
+        // empty entry
+        if (_cli_args[i].key == NULL) {
+            // update index only if no place is found yet
+            if (index_to_use == -1)
+                index_to_use = i;
+        }
+        // entry with the same name
+        else if (!strcmp(_cli_args[i].key, key)) {
+            index_to_use = i;
+            break;
+        }
+    }
+    // no space for the argument
+    if (index_to_use == -1) {
+        return false;
+    }
+    _cli_args[index_to_use].key = key;
+    _cli_args[index_to_use].value = value;
+    return true;
+}
+
+const char *cli_arg_get(const char *key) {
+    for (int i = 0; i < MAX_CLI_ARGS; ++i) {
+        if (_cli_args[i].key == NULL) {
+            continue;
+        }
+        if (strcmp(_cli_args[i].key, key)) {
+            continue;
+        }
+        return _cli_args[i].value;
+    }
+    return NULL;
+}