class CodedOutputStream

class CodedOutputStream {
    private $buffer;
    private $buffer_size;
    private $current;
    const MAX_VARINT64_BYTES = 10;
    public function __construct($size) {
        $this->current = 0;
        $this->buffer_size = $size;
        $this->buffer = str_repeat(chr(0), $this->buffer_size);
    }
    public function getData() {
        return $this->buffer;
    }
    public function writeVarint32($value, $trim) {
        $bytes = str_repeat(chr(0), self::MAX_VARINT64_BYTES);
        $size = self::writeVarintToArray($value, $bytes, $trim);
        return $this->writeRaw($bytes, $size);
    }
    public function writeVarint64($value) {
        $bytes = str_repeat(chr(0), self::MAX_VARINT64_BYTES);
        $size = self::writeVarintToArray($value, $bytes);
        return $this->writeRaw($bytes, $size);
    }
    public function writeLittleEndian32($value) {
        $bytes = str_repeat(chr(0), 4);
        $size = self::writeLittleEndian32ToArray($value, $bytes);
        return $this->writeRaw($bytes, $size);
    }
    public function writeLittleEndian64($value) {
        $bytes = str_repeat(chr(0), 8);
        $size = self::writeLittleEndian64ToArray($value, $bytes);
        return $this->writeRaw($bytes, $size);
    }
    public function writeTag($tag) {
        return $this->writeVarint32($tag, true);
    }
    public function writeRaw($data, $size) {
        if ($this->buffer_size < $size) {
            trigger_error("Output stream doesn't have enough buffer.");
            return false;
        }
        for ($i = 0; $i < $size; $i++) {
            $this->buffer[$this->current] = $data[$i];
            $this->current++;
            $this->buffer_size--;
        }
        return true;
    }
    public static function writeVarintToArray($value, &$buffer, $trim = false) {
        $current = 0;
        $high = 0;
        $low = 0;
        if (PHP_INT_SIZE == 4) {
            GPBUtil::divideInt64ToInt32($value, $high, $low, $trim);
        }
        else {
            $low = $value;
        }
        while ($low >= 0x80 || $low < 0 || $high != 0) {
            $buffer[$current] = chr($low | 0x80);
            $value = $value >> 7 & ~(0x7f << (PHP_INT_SIZE << 3) - 7);
            $carry = ($high & 0x7f) << (PHP_INT_SIZE << 3) - 7;
            $high = $high >> 7 & ~(0x7f << (PHP_INT_SIZE << 3) - 7);
            $low = $low >> 7 & ~(0x7f << (PHP_INT_SIZE << 3) - 7) | $carry;
            $current++;
        }
        $buffer[$current] = chr($low);
        return $current + 1;
    }
    private static function writeLittleEndian32ToArray($value, &$buffer) {
        $buffer[0] = chr($value & 0xff);
        $buffer[1] = chr($value >> 8 & 0xff);
        $buffer[2] = chr($value >> 16 & 0xff);
        $buffer[3] = chr($value >> 24 & 0xff);
        return 4;
    }
    private static function writeLittleEndian64ToArray($value, &$buffer) {
        $high = 0;
        $low = 0;
        if (PHP_INT_SIZE == 4) {
            GPBUtil::divideInt64ToInt32($value, $high, $low);
        }
        else {
            $low = $value & 0xffffffff;
            $high = $value >> 32 & 0xffffffff;
        }
        $buffer[0] = chr($low & 0xff);
        $buffer[1] = chr($low >> 8 & 0xff);
        $buffer[2] = chr($low >> 16 & 0xff);
        $buffer[3] = chr($low >> 24 & 0xff);
        $buffer[4] = chr($high & 0xff);
        $buffer[5] = chr($high >> 8 & 0xff);
        $buffer[6] = chr($high >> 16 & 0xff);
        $buffer[7] = chr($high >> 24 & 0xff);
        return 8;
    }

}