Add 'u' format modifier for unsigned int/hex

core/string/ustring.cpp

@@ -4842,6 +4842,7 @@ String String::sprintf(const Array &values, bool *error) const {
 	bool pad_with_zeros = false;
 	bool left_justified = false;
 	bool show_sign = false;
+	bool as_unsigned = false;
 
 	if (error) {
 		*error = true;
@@ -4882,16 +4883,27 @@ String String::sprintf(const Array &values, bool *error) const {
 						case 'x':
 							break;
 						case 'X':
-							base = 16;
 							capitalize = true;
 							break;
 					}
 					// Get basic number.
-					String str = String::num_int64(ABS(value), base, capitalize);
+					String str;
+					if (!as_unsigned) {
+						str = String::num_int64(ABS(value), base, capitalize);
+					} else {
+						uint64_t uvalue = *((uint64_t *)&value);
+						// In unsigned hex, if the value fits in 32 bits, trim it down to that.
+						if (base == 16 && value < 0 && value >= INT32_MIN) {
+							uvalue &= 0xffffffff;
+						}
+						str = String::num_uint64(uvalue, base, capitalize);
+					}
 					int number_len = str.length();
 
+					bool negative = value < 0 && !as_unsigned;
+
 					// Padding.
-					int pad_chars_count = (value < 0 || show_sign) ? min_chars - 1 : min_chars;
+					int pad_chars_count = (negative || show_sign) ? min_chars - 1 : min_chars;
 					String pad_char = pad_with_zeros ? String("0") : String(" ");
 					if (left_justified) {
 						str = str.rpad(pad_chars_count, pad_char);
@@ -4900,8 +4912,8 @@ String String::sprintf(const Array &values, bool *error) const {
 					}
 
 					// Sign.
-					if (show_sign || value < 0) {
-						String sign_char = value < 0 ? "-" : "+";
+					if (show_sign || negative) {
+						String sign_char = negative ? "-" : "+";
 						if (left_justified) {
 							str = str.insert(0, sign_char);
 						} else {
@@ -5094,6 +5106,10 @@ String String::sprintf(const Array &values, bool *error) const {
 					show_sign = true;
 					break;
 				}
+				case 'u': { // Treat as unsigned (for int/hex).
+					as_unsigned = true;
+					break;
+				}
 				case '0':
 				case '1':
 				case '2':