StringObject\StrObj::findUtf8CharAt()

Complexity

Conditions	17
Paths	17

Size

Total Lines	67
Code Lines	33

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	1

<?php
    protected function findUtf8CharAt($offset)
    {
        $byte = \ord($this->raw{$offset});

        if ($byte <= 0b01111111) {
            // ASCII passthru, 1 byte long
            return [$offset, 1, true, $byte];
        }

        if ($byte <= 0b10111111) {
            // either part of a UTF8 char, or an invalid UTF8 codepoint.
            // try to find start of UTF8 char
            $original = $offset;
            while ($offset > 0 && $original - $offset < 4) {
                $prev = \ord($this->raw{--$offset});

                if ($prev <= 0b01111111) {
                    // prev is plain ASCII so current char can't be valid
                    return [$original, 1, false, $byte];
                }

                if ($prev <= 0b10111111) {
                    // prev is also part of a UTF8 char, so keep looking
                    continue;
                }

                if ($prev == 0xC0 || $prev == 0xC1) {
                    // prev is an invalid UTF8 starter for overlong ASCII
                    return [$offset, 2, false, $byte];
                }

                if ($prev <= 0b11110100) {
                    // prev is valid start byte, validate length to check this char
                    if ($original < $offset + self::calcUtf8CharLength($prev)) {
                        return [$offset, $length, true, $byte];

The variable $length seems only to be defined at a later point. Did you maybe move this code here without moving the variable definition?

                    }
                }
                return [$original, 1, false, $byte];
            }
            return [$original, 1, false, $byte];
        }

        if ($byte <= 0b11110100) {
            // valid UTF8 start byte, find the rest, determine if length is valid
            $actual = $length = self::calcUtf8CharLength($byte);

            for ($i = 1; $i < $length; $i++) {
                if ($offset + $i >= $this->length()) {
                    $actual = $i - 1;
                    break;
                }
                $last = \ord($this->raw{$offset + $i});
                if ($last < 0b10000000 || $last > 0b10111111) {
                    $actual = $i;
                    break;
                }
            }

            if ($actual !== $length) {
                return [$offset, $actual, false, $byte];
            }
            return [$offset, $length, true, $byte];
        }

        // if 245 to 255, Windows-1252 passthru
        return [$offset, 1, false, $byte];
    }