Add defaults to compare_exchange, small fix in printf. Disallow obviously wrong code that returns the pointer to a variable on the stack.

lib/std/net/net.c3

@@ -6,4 +6,40 @@ fault NetError
 	URL_TOO_LONG,
 	INVALID_SOCKET,
 	GENERAL_ERROR,
+	INVALID_IP_STRING,
+}
+
+fn uint! ipv4toint(String s)
+{
+	uint out;
+	int element;
+	int current = -1;
+	foreach (c : s)
+	{
+		if (c == '.')
+		{
+			if (current < 0) return NetError.INVALID_IP_STRING!;
+			out = out << 8 + current;
+			current = -1;
+			element++;
+			continue;
+		}
+		if (element > 3 || c < '0' || c > '9') return NetError.INVALID_IP_STRING!;
+		if (current < 0)
+		{
+			current = c - '0';
+			continue;
+		}
+		current = current * 10 + c - '0';
+	}
+	if (element != 3 || current < 0) return NetError.INVALID_IP_STRING!;
+	out = out << 8 + current;
+	return out;
+}
+
+fn String! inttoipv4(uint val, Allocator* allocator = mem::current_allocator())
+{
+	char[3 * 4 + 3 + 1] buffer;
+	String res = (String)io::bprintf(&buffer, "%d.%d.%d.%d", val >> 24, (val >> 16) & 0xFF, (val >> 8) & 0xFF, val & 0xFF)?;
+	return res.copyz(allocator);
 }