Rewrite a BRSTM as an HPS

<?

// open a brstm in binary mode as $fp

fseek($fp, 8, SEEK_SET);
$rstmSize = hexdec(bin2hex(fread($fp, 4)));
fseek($fp, 16, SEEK_SET);   // Reading section offsets
$rstmInfoOffset = hexdec(bin2hex(fread($fp, 4)));
$rstmInfoSize = hexdec(bin2hex(fread($fp, 4)));
$rstmSeekOffset = hexdec(bin2hex(fread($fp, 4)));
$rstmSeekSize = hexdec(bin2hex(fread($fp, 4)));
$rstmDataOffset = hexdec(bin2hex(fread($fp, 4)));
$rstmDataSize = hexdec(bin2hex(fread($fp, 4))) - 0x20;
fseek($fp, 0x60, SEEK_SET);
$format = hexdec(bin2hex(fread($fp, 1)));
$loopFlag = hexdec(bin2hex(fread($fp, 1)));
$channelCount = hexdec(bin2hex(fread($fp, 1)));
$nibbleCount = $rstmDataSize / $channelCount * 2;
fseek($fp, 1, SEEK_CUR);
$sampleRate = hexdec(bin2hex(fread($fp, 2)));
fseek($fp, 2, SEEK_CUR);
$loopStart = hexdec(bin2hex(fread($fp, 4)));
$loopStartNibbles = floor(($loopStart * $channelCount * 8 / 14));
$sampleCount = hexdec(bin2hex(fread($fp, 4)));
//$loopEndNibbles = $nibbleCount - 1;
$loopEndNibbles = floor(($sampleCount * $channelCount * 8 / 14) - 1);

// fetching coefficients, initial state, and loop context
fseek($fp, 0x5c, SEEK_SET);
$coeffPtr1 = hexdec(bin2hex(fread($fp, 4)));
fseek($fp, 0x50 + $coeffPtr1, SEEK_SET);
$coeffPtr2 = hexdec(bin2hex(fread($fp, 4)));
fseek($fp, 0x50 + $coeffPtr2, SEEK_SET);
$coeffL =  fread($fp, 0x30);
if ($channelCount == 2) {
    fseek($fp, 8, SEEK_CUR);
    $coeffR =  fread($fp, 0x30);
}
fseek($fp, 0x78, SEEK_SET);
$interleave = hexdec(bin2hex(fread($fp, 4)));
fseek($fp, 0x88, SEEK_SET);
$interleaveShortBlock = hexdec(bin2hex(fread($fp, 4)));

if ($downloadtype == "hps") {
    print(" HALPST" . pack("CNN", 0, $sampleRate, $channelCount));
    $firstBlockSize = $blockSize = 0x10000;
    // writing first channel
    print(pack("NNNN", $blockSize, $channelCount, $nibbleCount, 2) . substr($coeffL, 0, 0x28));
    if ($channelCount == 2)
        print(pack("NNNN", $blockSize, $channelCount, $nibbleCount, 2) . substr($coeffR, 0, 0x28));
    // Writing blocks
    if ($loopFlag) {
        $preLoopBlockCount = floor($loopStart/57344);
        if ($loopStart < 57344) {
            if ($loopStart)
                $preLoopBlockSize = $loopStart * 16/14 + 0x20;
            else
                $preLoopBlockSize = 0;
            $loopStartBlock = 0x80 + $preLoopBlockSize;
        }
        else if ($loopStart % 57344 == 0)
            $preLoopBlockSize = 0;

        else {
            $preLoopBlockSize = ($loopStart % 57344) * 16/14 + 0x20;
        }
        $loopStartBlock = 0x80 + $preLoopBlockCount * ($blockSize + 0x20) + $preLoopBlockSize;
    }
    else {
        $preLoopBlockCount = $preLoopBlockSize = 0;
        $loopStartBlock = 0xffffffff;
    }
    $blockCount = floor(($rstmDataSize - $loopStartNibbles - $interleaveShortBlock * 2) / 0x10000);
    $lastBlockSize = ($rstmDataSize - $loopStartNibbles) % 0x10000;
    $currentOffset = 0x80;
    header( 'Content-Length: ' . 0x80 + ($preLoopBlockCount + $blockCount) * ($blockSize + 0x20) + $preLoopBlockSize + 0x20 + $lastBlockSize + 0x20 );
    fseek($fp, $rstmDataOffset + 0x20, SEEK_SET);
    for ($i = 0; $i < $preLoopBlockCount; $i++) {
        print(pack("NNN", $blockSize, $blockSize-1, $currentOffset + $blockSize + 0x20) . substr($coeffL, 0x22, 6) . pack("n", 0) . substr($coeffR, 0x22, 6) . pack("nN", 0, 0));
        $currentOffset += $blockSize + 0x20;
        print(fread($fp, 0x2000));
        for ($j = 0; $j < ($blockSize / 0x4000 - 1); $j++) {
            fseek($fp, 0x2000, SEEK_CUR);
            print(fread($fp, 0x2000));
        }
        fseek($fp, -($j * 0x4000), SEEK_CUR);
        print(fread($fp, 0x2000));
        for ($j = 0; $j < ($blockSize / 0x4000 - 1); $j++) {
            fseek($fp, 0x2000, SEEK_CUR);
            print(fread($fp, 0x2000));
        }
    }
    // Printing block before loopStart
    if ($preLoopBlockSize) {
    print(pack("NNN", $preLoopBlockSize - 0x20, $preLoopBlockSize-0x21, $currentOffset + $preLoopBlockSize) . substr($coeffL, 0x22, 6) . pack("n", 0) . substr($coeffR, 0x22, 6) . pack("nN", 0, 0));
        $currentOffset += $preLoopBlockSize;
        print(fread($fp, 0x2000));
        for ($j = 0; $j < (($preLoopBlockSize-0x20) / 0x4000 - 1); $j++) {
            fseek($fp, 0x2000, SEEK_CUR);
            print(fread($fp, 0x2000));
        }
        fseek($fp, -($j * 0x4000), SEEK_CUR);
        print(fread($fp, 0x2000));
        for ($j = 0; $j < (($preLoopBlockSize-0x20) / 0x4000 - 1); $j++) {
            fseek($fp, 0x2000, SEEK_CUR);
            print(fread($fp, 0x2000));
        }
    }
    // Writing rest
    for ($i = 0; $i < $blockCount; $i++) {
        print(pack("NNN", $blockSize, $blockSize-1, $currentOffset + $blockSize + 0x20) . substr($coeffL, 0x22, 6) . pack("n", 0) . substr($coeffR, 0x22, 6) . pack("nN", 0, 0));
        $currentOffset += $blockSize + 0x20;
        print(fread($fp, 0x2000));
        fseek($fp, 0x2000, SEEK_CUR);
        print(fread($fp, 0x2000));
        fseek($fp, 0x2000, SEEK_CUR);
        print(fread($fp, 0x2000));
        fseek($fp, 0x2000, SEEK_CUR);
        print(fread($fp, 0x2000));
        fseek($fp, -0xc000, SEEK_CUR);
        print(fread($fp, 0x2000));
        fseek($fp, 0x2000, SEEK_CUR);
        print(fread($fp, 0x2000));
        fseek($fp, 0x2000, SEEK_CUR);
        print(fread($fp, 0x2000));
        fseek($fp, 0x2000, SEEK_CUR);
        print(fread($fp, 0x2000));
    }
    // Writing last block
    print(pack("NNN", $lastBlockSize, $lastBlockSize - 1, $loopStartBlock) . substr($coeffL, 0x22, 6) . pack("n", 0) . substr($coeffR, 0x22, 6) . pack("nN", 0, 0));
    $i = 0;
    fseek($fp, -($lastBlockSize), SEEK_END);
    if ($lastBlockSize >= 0x4000) {
        print(fread($fp, 0x2000));
        fseek($fp, 0x2000, SEEK_CUR);
        for ($i = 0; $i < (floor($lastBlockSize / 0x4000) - 1); $i++) {
            print(fread($fp, 0x2000));
            fseek($fp, 0x2000, SEEK_CUR);
        }
    }

    print(fread($fp, $interleaveShortBlock));

    fseek($fp, -$lastBlockSize, SEEK_END);
    if ($lastBlockSize >= 0x4000) {
        fseek($fp, 0x2000, SEEK_CUR);
        print(fread($fp, 0x2000));
        for ($i = 0; $i < (floor($lastBlockSize / 0x4000) - 1); $i++) {
            fseek($fp, 0x2000, SEEK_CUR);
            print(fread($fp, 0x2000));
        }
    }
    fseek($fp, -($interleaveShortBlock), SEEK_END);
    print(fread($fp, $interleaveShortBlock));
}

?>