jodd-core/src/main/java/jodd/util/StringUtil.java
public static int indexOf(final String src, final char c, int startIndex, int endIndex) {
		if (startIndex < 0) {
			startIndex = 0;
		}
		int srclen = src.length();
		if (endIndex > srclen) {
			endIndex = srclen;
		}
		for (int i = startIndex; i < endIndex; i++) {
			if (src.charAt(i) == c) {
				return i;
			}
		}
		return -1;
	}
public static int indexOf(final String src, final char c, int startIndex, int endIndex) {
		if (startIndex < 0) {
			startIndex = 0;
		}
		int srclen = src.length();
		if (endIndex > srclen) {
			endIndex = srclen;
		}
		for (int i = startIndex; i < endIndex; i++) {
			if (src.charAt(i) == c) {
				return i;
			}
		}
		return -1;
	}
Finds the first occurrence of a character in the given source but within limited range (start, end].