static boolean regionMatches()

in src/main/java/org/apache/commons/lang3/CharSequenceUtils.java [294:338]
33 lines of code
13 McCabe index (conditional complexity)

    static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int thisStart,
            final CharSequence substring, final int start, final int length)    {
        if (cs instanceof String && substring instanceof String) {
            return ((String) cs).regionMatches(ignoreCase, thisStart, (String) substring, start, length);
        }
        int index1 = thisStart;
        int index2 = start;
        int tmpLen = length;

        // Extract these first so we detect NPEs the same as the java.lang.String version
        final int srcLen = cs.length() - thisStart;
        final int otherLen = substring.length() - start;

        // Check for invalid parameters
        if (thisStart < 0 || start < 0 || length < 0) {
            return false;
        }

        // Check that the regions are long enough
        if (srcLen < length || otherLen < length) {
            return false;
        }

        while (tmpLen-- > 0) {
            final char c1 = cs.charAt(index1++);
            final char c2 = substring.charAt(index2++);

            if (c1 == c2) {
                continue;
            }

            if (!ignoreCase) {
                return false;
            }

            // The real same check as in String.regionMatches():
            final char u1 = Character.toUpperCase(c1);
            final char u2 = Character.toUpperCase(c2);
            if (u1 != u2 && Character.toLowerCase(u1) != Character.toLowerCase(u2)) {
                return false;
            }
        }

        return true;
    }