BCD (Binary Coded Decimals): PHP parsing library

<?php
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

/**
 * BCD (Binary Coded Decimals) is a common way to encode integer
 * numbers in a way that makes human-readable output somewhat
 * simpler. In this encoding scheme, every decimal digit is encoded as
 * either a single byte (8 bits), or a nibble (half of a byte, 4
 * bits). This obviously wastes a lot of bits, but it makes translation
 * into human-readable string much easier than traditional
 * binary-to-decimal conversion process, which includes lots of
 * divisions by 10.
 * 
 * For example, encoding integer 31337 in 8-digit, 8 bits per digit,
 * big endian order of digits BCD format yields
 * 
 * ```
 * 00 00 00 03 01 03 03 07
 * ```
 * 
 * Encoding the same integer as 8-digit, 4 bits per digit, little
 * endian order BCD format would yield:
 * 
 * ```
 * 73 31 30 00
 * ```
 * 
 * Using this type of encoding in Kaitai Struct is pretty
 * straightforward: one calls for this type, specifying desired
 * encoding parameters, and gets result using either `as_int` or
 * `as_str` attributes.
 */

namespace {
    class Bcd extends \Kaitai\Struct\Struct {
        public function __construct(int $numDigits, int $bitsPerDigit, bool $isLe, \Kaitai\Struct\Stream $_io, \Kaitai\Struct\Struct $_parent = null, \Bcd $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_m_numDigits = $numDigits;
            $this->_m_bitsPerDigit = $bitsPerDigit;
            $this->_m_isLe = $isLe;
            $this->_read();
        }

        private function _read() {
            $this->_m_digits = [];
            $n = $this->numDigits();
            for ($i = 0; $i < $n; $i++) {
                switch ($this->bitsPerDigit()) {
                    case 4:
                        $this->_m_digits[] = $this->_io->readBitsIntBe(4);
                        break;
                    case 8:
                        $this->_m_digits[] = $this->_io->readU1();
                        break;
                }
            }
        }
        protected $_m_asInt;

        /**
         * Value of this BCD number as integer. Endianness would be selected based on `is_le` parameter given.
         */
        public function asInt() {
            if ($this->_m_asInt !== null)
                return $this->_m_asInt;
            $this->_m_asInt = ($this->isLe() ? $this->asIntLe() : $this->asIntBe());
            return $this->_m_asInt;
        }
        protected $_m_asIntLe;

        /**
         * Value of this BCD number as integer (treating digit order as little-endian).
         */
        public function asIntLe() {
            if ($this->_m_asIntLe !== null)
                return $this->_m_asIntLe;
            $this->_m_asIntLe = ($this->digits()[0] + ($this->numDigits() < 2 ? 0 : (($this->digits()[1] * 10) + ($this->numDigits() < 3 ? 0 : (($this->digits()[2] * 100) + ($this->numDigits() < 4 ? 0 : (($this->digits()[3] * 1000) + ($this->numDigits() < 5 ? 0 : (($this->digits()[4] * 10000) + ($this->numDigits() < 6 ? 0 : (($this->digits()[5] * 100000) + ($this->numDigits() < 7 ? 0 : (($this->digits()[6] * 1000000) + ($this->numDigits() < 8 ? 0 : ($this->digits()[7] * 10000000)))))))))))))));
            return $this->_m_asIntLe;
        }
        protected $_m_lastIdx;

        /**
         * Index of last digit (0-based).
         */
        public function lastIdx() {
            if ($this->_m_lastIdx !== null)
                return $this->_m_lastIdx;
            $this->_m_lastIdx = ($this->numDigits() - 1);
            return $this->_m_lastIdx;
        }
        protected $_m_asIntBe;

        /**
         * Value of this BCD number as integer (treating digit order as big-endian).
         */
        public function asIntBe() {
            if ($this->_m_asIntBe !== null)
                return $this->_m_asIntBe;
            $this->_m_asIntBe = ($this->digits()[$this->lastIdx()] + ($this->numDigits() < 2 ? 0 : (($this->digits()[($this->lastIdx() - 1)] * 10) + ($this->numDigits() < 3 ? 0 : (($this->digits()[($this->lastIdx() - 2)] * 100) + ($this->numDigits() < 4 ? 0 : (($this->digits()[($this->lastIdx() - 3)] * 1000) + ($this->numDigits() < 5 ? 0 : (($this->digits()[($this->lastIdx() - 4)] * 10000) + ($this->numDigits() < 6 ? 0 : (($this->digits()[($this->lastIdx() - 5)] * 100000) + ($this->numDigits() < 7 ? 0 : (($this->digits()[($this->lastIdx() - 6)] * 1000000) + ($this->numDigits() < 8 ? 0 : ($this->digits()[($this->lastIdx() - 7)] * 10000000)))))))))))))));
            return $this->_m_asIntBe;
        }
        protected $_m_digits;
        protected $_m_numDigits;
        protected $_m_bitsPerDigit;
        protected $_m_isLe;
        public function digits() { return $this->_m_digits; }

        /**
         * Number of digits in this BCD representation. Only values from 1 to 8 inclusive are supported.
         */
        public function numDigits() { return $this->_m_numDigits; }

        /**
         * Number of bits per digit. Only values of 4 and 8 are supported.
         */
        public function bitsPerDigit() { return $this->_m_bitsPerDigit; }

        /**
         * Endianness used by this BCD representation. True means little-endian, false is for big-endian.
         */
        public function isLe() { return $this->_m_isLe; }
    }
}