GENMIDI.OP2 OPL2 sound bank: PHP parsing library

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

/**
 * GENMIDI.OP2 is a sound bank file used by players based on DMX sound
 * library to play MIDI files with General MIDI instruments using OPL2
 * sound chip (which was commonly installed on popular AdLib and Sound
 * Blaster sound cards).
 * 
 * Major users of DMX sound library include:
 * 
 * * Original Doom game engine (and games based on it: Heretic, Hexen, Strife, Chex Quest)
 * * Raptor: Call of the Shadows
 */

namespace {
    class GenmidiOp2 extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \Kaitai\Struct\Struct $_parent = null, \GenmidiOp2 $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_magic = $this->_io->readBytes(8);
            if (!($this->magic() == "\x23\x4F\x50\x4C\x5F\x49\x49\x23")) {
                throw new \Kaitai\Struct\Error\ValidationNotEqualError("\x23\x4F\x50\x4C\x5F\x49\x49\x23", $this->magic(), $this->_io(), "/seq/0");
            }
            $this->_m_instruments = [];
            $n = 175;
            for ($i = 0; $i < $n; $i++) {
                $this->_m_instruments[] = new \GenmidiOp2\InstrumentEntry($this->_io, $this, $this->_root);
            }
            $this->_m_instrumentNames = [];
            $n = 175;
            for ($i = 0; $i < $n; $i++) {
                $this->_m_instrumentNames[] = \Kaitai\Struct\Stream::bytesToStr(\Kaitai\Struct\Stream::bytesTerminate(\Kaitai\Struct\Stream::bytesStripRight($this->_io->readBytes(32), 0), 0, false), "ASCII");
            }
        }
        protected $_m_magic;
        protected $_m_instruments;
        protected $_m_instrumentNames;
        public function magic() { return $this->_m_magic; }
        public function instruments() { return $this->_m_instruments; }
        public function instrumentNames() { return $this->_m_instrumentNames; }
    }
}

namespace GenmidiOp2 {
    class InstrumentEntry extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \GenmidiOp2 $_parent = null, \GenmidiOp2 $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_flags = $this->_io->readU2le();
            $this->_m_finetune = $this->_io->readU1();
            $this->_m_note = $this->_io->readU1();
            $this->_m_instruments = [];
            $n = 2;
            for ($i = 0; $i < $n; $i++) {
                $this->_m_instruments[] = new \GenmidiOp2\Instrument($this->_io, $this, $this->_root);
            }
        }
        protected $_m_flags;
        protected $_m_finetune;
        protected $_m_note;
        protected $_m_instruments;
        public function flags() { return $this->_m_flags; }
        public function finetune() { return $this->_m_finetune; }

        /**
         * MIDI note for fixed instruments, 0 otherwise
         */
        public function note() { return $this->_m_note; }
        public function instruments() { return $this->_m_instruments; }
    }
}

namespace GenmidiOp2 {
    class Instrument extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \GenmidiOp2\InstrumentEntry $_parent = null, \GenmidiOp2 $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_op1 = new \GenmidiOp2\OpSettings($this->_io, $this, $this->_root);
            $this->_m_feedback = $this->_io->readU1();
            $this->_m_op2 = new \GenmidiOp2\OpSettings($this->_io, $this, $this->_root);
            $this->_m_unused = $this->_io->readU1();
            $this->_m_baseNote = $this->_io->readS2le();
        }
        protected $_m_op1;
        protected $_m_feedback;
        protected $_m_op2;
        protected $_m_unused;
        protected $_m_baseNote;
        public function op1() { return $this->_m_op1; }

        /**
         * Feedback/AM-FM (both operators)
         */
        public function feedback() { return $this->_m_feedback; }
        public function op2() { return $this->_m_op2; }
        public function unused() { return $this->_m_unused; }

        /**
         * Base note offset
         */
        public function baseNote() { return $this->_m_baseNote; }
    }
}

/**
 * OPL2 settings for one operator (carrier or modulator)
 */

namespace GenmidiOp2 {
    class OpSettings extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \GenmidiOp2\Instrument $_parent = null, \GenmidiOp2 $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_tremVibr = $this->_io->readU1();
            $this->_m_attDec = $this->_io->readU1();
            $this->_m_sustRel = $this->_io->readU1();
            $this->_m_wave = $this->_io->readU1();
            $this->_m_scale = $this->_io->readU1();
            $this->_m_level = $this->_io->readU1();
        }
        protected $_m_tremVibr;
        protected $_m_attDec;
        protected $_m_sustRel;
        protected $_m_wave;
        protected $_m_scale;
        protected $_m_level;

        /**
         * Tremolo/vibrato/sustain/KSR/multi
         */
        public function tremVibr() { return $this->_m_tremVibr; }

        /**
         * Attack rate/decay rate
         */
        public function attDec() { return $this->_m_attDec; }

        /**
         * Sustain level/release rate
         */
        public function sustRel() { return $this->_m_sustRel; }

        /**
         * Waveform select
         */
        public function wave() { return $this->_m_wave; }

        /**
         * Key scale level
         */
        public function scale() { return $this->_m_scale; }

        /**
         * Output level
         */
        public function level() { return $this->_m_level; }
    }
}