working config file

src/string.c

@@ -0,0 +1,64 @@
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "string.h"
+
+char *string_concat(const char *s1, const char *s2) {
+  char *result;
+
+  result = malloc(strlen(s1) + strlen(s2) + 1); // +1 for the null-terminator
+
+  strcpy(result, s1);
+  strcat(result, s2);
+
+  return result;
+}
+
+unsigned int string_trim(char *str) {
+  // https://www.delftstack.com/howto/c/trim-string-in-c/
+  unsigned int start;
+  unsigned int end;
+
+  start = 0;
+  end = strlen(str) - 1;
+
+  if (end == 0) {
+    return 0;
+  }
+
+  // Remove leading whitespace
+  while (str[start] == ' ') {
+    start++;
+  }
+
+  // Remove trailing whitespace
+  while (end > start && str[end] == ' ') {
+    end--;
+  }
+
+  // If the string was trimmed, adjust the null terminator
+  if (start > 0 || end < (strlen(str) - 1)) {
+    memmove(str, str + start, end - start + 1);
+    str[end - start + 1] = '\0';
+  }
+
+  return end - start + 1;
+}
+
+static bool is_digit(char c) { return c >= '0' && c <= '9'; }
+
+bool string_is_number(char *value) {
+  unsigned long value_len;
+  unsigned int i;
+  if (value == NULL) {
+    return false;
+  }
+  value_len = strlen(value);
+  for (i = 0; i < value_len; i++) {
+    if (!is_digit(value[i])) {
+      return false;
+    }
+  }
+  return true;
+}