<?php


> declare(strict_types=1);
namespace MaxMind\Db\Reader;
> 



// @codingStandardsIgnoreLine
use RuntimeException;

/**
 * @ignore
 *
 * We subtract 1 from the log to protect against precision loss.
 */
\define(__NAMESPACE__ . '\_MM_MAX_INT_BYTES', (log(PHP_INT_MAX, 2) - 1) / 8);

class Decoder
{

>     /**
    private $fileStream;
>      * @var resource
    private $pointerBase;
>      */


    private $pointerBaseByteSize;

>     /**
    // This is only used for unit testing
>      * @var int
    private $pointerTestHack;
>      */


    private $switchByteOrder;

>     /**

>      * @var float
    /** @ignore */
>      */



<     // This is only used for unit testing



>     /**
>      * This is only used for unit testing.
>      *
>      * @var bool
>      */


    /** @ignore */

>     /**
    const _POINTER = 1;
>      * @var bool
    /** @ignore */
>      */



<     /** @ignore */
<     const _EXTENDED = 0;
<     /** @ignore */
<     const _POINTER = 1;
<     /** @ignore */
<     const _UTF8_STRING = 2;
<     /** @ignore */
<     const _DOUBLE = 3;
<     /** @ignore */
<     const _BYTES = 4;
<     /** @ignore */
<     const _UINT16 = 5;
<     /** @ignore */
<     const _UINT32 = 6;
<     /** @ignore */
<     const _MAP = 7;
<     /** @ignore */
<     const _INT32 = 8;
<     /** @ignore */
<     const _UINT64 = 9;
<     /** @ignore */
<     const _UINT128 = 10;
<     /** @ignore */
<     const _ARRAY = 11;
<     /** @ignore */
<     const _CONTAINER = 12;
<     /** @ignore */
<     const _END_MARKER = 13;
<     /** @ignore */
<     const _BOOLEAN = 14;
<     /** @ignore */
<     const _FLOAT = 15;



>     private const _EXTENDED = 0;
>     private const _POINTER = 1;
>     private const _UTF8_STRING = 2;
>     private const _DOUBLE = 3;
>     private const _BYTES = 4;
>     private const _UINT16 = 5;
>     private const _UINT32 = 6;
>     private const _MAP = 7;
>     private const _INT32 = 8;
>     private const _UINT64 = 9;
>     private const _UINT128 = 10;
>     private const _ARRAY = 11;
>     private const _CONTAINER = 12;
>     private const _END_MARKER = 13;
>     private const _BOOLEAN = 14;
>     private const _FLOAT = 15;


    ) {

>     /**
        $this->fileStream = $fileStream;
>      * @param resource $fileStream
        $this->pointerBase = $pointerBase;
>      */



<         $pointerBase = 0,
<         $pointerTestHack = false



>         int $pointerBase = 0,
>         bool $pointerTestHack = false


        $this->pointerTestHack = $pointerTestHack;

        $this->switchByteOrder = $this->isPlatformLittleEndian();
    }


<     public function decode($offset)



>     public function decode(int $offset): array


    {
        $ctrlByte = \ord(Util::read($this->fileStream, $offset, 1));
        ++$offset;

        $type = $ctrlByte >> 5;

        // Pointers are a special case, we don't read the next $size bytes, we
        // use the size to determine the length of the pointer and then follow
        // it.
        if ($type === self::_POINTER) {

<             list($pointer, $offset) = $this->decodePointer($ctrlByte, $offset);



>             [$pointer, $offset] = $this->decodePointer($ctrlByte, $offset);



            // for unit testing
            if ($this->pointerTestHack) {
                return [$pointer];
            }


<             list($result) = $this->decode($pointer);



>             [$result] = $this->decode($pointer);



            return [$result, $offset];
        }

        if ($type === self::_EXTENDED) {
            $nextByte = \ord(Util::read($this->fileStream, $offset, 1));

            $type = $nextByte + 7;

            if ($type < 8) {
                throw new InvalidDatabaseException(
                    'Something went horribly wrong in the decoder. An extended type '
                    . 'resolved to a type number < 8 ('
                    . $type
                    . ')'
                );
            }

            ++$offset;
        }


<         list($size, $offset) = $this->sizeFromCtrlByte($ctrlByte, $offset);



>         [$size, $offset] = $this->sizeFromCtrlByte($ctrlByte, $offset);



        return $this->decodeByType($type, $offset, $size);
    }


<     private function decodeByType($type, $offset, $size)



>     private function decodeByType(int $type, int $offset, int $size): array


    {
        switch ($type) {
            case self::_MAP:
                return $this->decodeMap($size, $offset);
            case self::_ARRAY:
                return $this->decodeArray($size, $offset);
            case self::_BOOLEAN:
                return [$this->decodeBoolean($size), $offset];
        }

        $newOffset = $offset + $size;
        $bytes = Util::read($this->fileStream, $offset, $size);
        switch ($type) {
            case self::_BYTES:
            case self::_UTF8_STRING:
                return [$bytes, $newOffset];
            case self::_DOUBLE:
                $this->verifySize(8, $size);

                return [$this->decodeDouble($bytes), $newOffset];
            case self::_FLOAT:
                $this->verifySize(4, $size);

                return [$this->decodeFloat($bytes), $newOffset];
            case self::_INT32:
                return [$this->decodeInt32($bytes, $size), $newOffset];
            case self::_UINT16:
            case self::_UINT32:
            case self::_UINT64:
            case self::_UINT128:
                return [$this->decodeUint($bytes, $size), $newOffset];
            default:
                throw new InvalidDatabaseException(
                    'Unknown or unexpected type: ' . $type
                );
        }
    }


<     private function verifySize($expected, $actual)



>     private function verifySize(int $expected, int $actual): void


    {
        if ($expected !== $actual) {
            throw new InvalidDatabaseException(
                "The MaxMind DB file's data section contains bad data (unknown data type or corrupt data)"
            );
        }
    }


<     private function decodeArray($size, $offset)



>     private function decodeArray(int $size, int $offset): array


    {
        $array = [];

        for ($i = 0; $i < $size; ++$i) {

<             list($value, $offset) = $this->decode($offset);
<             array_push($array, $value);



>             [$value, $offset] = $this->decode($offset);
>             $array[] = $value;


        }

        return [$array, $offset];
    }


<     private function decodeBoolean($size)



>     private function decodeBoolean(int $size): bool


    {

<         return $size === 0 ? false : true;



>         return $size !== 0;


    }


<     private function decodeDouble($bits)



>     private function decodeDouble(string $bytes): float


    {
        // This assumes IEEE 754 doubles, but most (all?) modern platforms
        // use them.

<         //
<         // We are not using the "E" format as that was only added in
<         // 7.0.15 and 7.1.1. As such, we must switch byte order on
<         // little endian machines.
<         list(, $double) = unpack('d', $this->maybeSwitchByteOrder($bits));



>         [, $double] = unpack('E', $bytes);



        return $double;
    }


<     private function decodeFloat($bits)



>     private function decodeFloat(string $bytes): float


    {
        // This assumes IEEE 754 floats, but most (all?) modern platforms
        // use them.

<         //
<         // We are not using the "G" format as that was only added in
<         // 7.0.15 and 7.1.1. As such, we must switch byte order on
<         // little endian machines.
<         list(, $float) = unpack('f', $this->maybeSwitchByteOrder($bits));



>         [, $float] = unpack('G', $bytes);



        return $float;
    }


<     private function decodeInt32($bytes, $size)



>     private function decodeInt32(string $bytes, int $size): int


    {
        switch ($size) {
            case 0:
                return 0;
            case 1:
            case 2:
            case 3:
                $bytes = str_pad($bytes, 4, "\x00", STR_PAD_LEFT);
                break;
            case 4:
                break;
            default:
                throw new InvalidDatabaseException(
                    "The MaxMind DB file's data section contains bad data (unknown data type or corrupt data)"
                );
        }


<         list(, $int) = unpack('l', $this->maybeSwitchByteOrder($bytes));



>         [, $int] = unpack('l', $this->maybeSwitchByteOrder($bytes));



        return $int;
    }


<     private function decodeMap($size, $offset)



>     private function decodeMap(int $size, int $offset): array


    {
        $map = [];

        for ($i = 0; $i < $size; ++$i) {

<             list($key, $offset) = $this->decode($offset);
<             list($value, $offset) = $this->decode($offset);



>             [$key, $offset] = $this->decode($offset);
>             [$value, $offset] = $this->decode($offset);


            $map[$key] = $value;
        }

        return [$map, $offset];
    }


<     private function decodePointer($ctrlByte, $offset)



>     private function decodePointer(int $ctrlByte, int $offset): array


    {
        $pointerSize = (($ctrlByte >> 3) & 0x3) + 1;

        $buffer = Util::read($this->fileStream, $offset, $pointerSize);
        $offset = $offset + $pointerSize;

        switch ($pointerSize) {
            case 1:
                $packed = \chr($ctrlByte & 0x7) . $buffer;

<                 list(, $pointer) = unpack('n', $packed);



>                 [, $pointer] = unpack('n', $packed);


                $pointer += $this->pointerBase;
                break;
            case 2:
                $packed = "\x00" . \chr($ctrlByte & 0x7) . $buffer;

<                 list(, $pointer) = unpack('N', $packed);



>                 [, $pointer] = unpack('N', $packed);


                $pointer += $this->pointerBase + 2048;
                break;
            case 3:
                $packed = \chr($ctrlByte & 0x7) . $buffer;

                // It is safe to use 'N' here, even on 32 bit machines as the
                // first bit is 0.

<                 list(, $pointer) = unpack('N', $packed);



>                 [, $pointer] = unpack('N', $packed);


                $pointer += $this->pointerBase + 526336;
                break;
            case 4:
                // We cannot use unpack here as we might overflow on 32 bit
                // machines
                $pointerOffset = $this->decodeUint($buffer, $pointerSize);

                $byteLength = $pointerSize + $this->pointerBaseByteSize;

                if ($byteLength <= _MM_MAX_INT_BYTES) {
                    $pointer = $pointerOffset + $this->pointerBase;
                } elseif (\extension_loaded('gmp')) {
                    $pointer = gmp_strval(gmp_add($pointerOffset, $this->pointerBase));
                } elseif (\extension_loaded('bcmath')) {

<                     $pointer = bcadd($pointerOffset, $this->pointerBase);



>                     $pointer = bcadd($pointerOffset, (string) $this->pointerBase);


                } else {
                    throw new RuntimeException(
                        'The gmp or bcmath extension must be installed to read this database.'
                    );
                }

>                 break;
        }
>             default:

>                 throw new InvalidDatabaseException(
        return [$pointer, $offset];
>                     'Unexpected pointer size ' . $pointerSize
    }
>                 );




<     private function decodeUint($bytes, $byteLength)



>     private function decodeUint(string $bytes, int $byteLength)


    {
        if ($byteLength === 0) {
            return 0;
        }

        $integer = 0;

        for ($i = 0; $i < $byteLength; ++$i) {
            $part = \ord($bytes[$i]);

            // We only use gmp or bcmath if the final value is too big
            if ($byteLength <= _MM_MAX_INT_BYTES) {
                $integer = ($integer << 8) + $part;
            } elseif (\extension_loaded('gmp')) {

<                 $integer = gmp_strval(gmp_add(gmp_mul($integer, 256), $part));



>                 $integer = gmp_strval(gmp_add(gmp_mul((string) $integer, '256'), $part));


            } elseif (\extension_loaded('bcmath')) {

<                 $integer = bcadd(bcmul($integer, 256), $part);



>                 $integer = bcadd(bcmul((string) $integer, '256'), (string) $part);


            } else {
                throw new RuntimeException(
                    'The gmp or bcmath extension must be installed to read this database.'
                );
            }
        }

        return $integer;
    }


<     private function sizeFromCtrlByte($ctrlByte, $offset)



>     private function sizeFromCtrlByte(int $ctrlByte, int $offset): array


    {
        $size = $ctrlByte & 0x1f;

        if ($size < 29) {
            return [$size, $offset];
        }

        $bytesToRead = $size - 28;
        $bytes = Util::read($this->fileStream, $offset, $bytesToRead);

        if ($size === 29) {
            $size = 29 + \ord($bytes);
        } elseif ($size === 30) {

<             list(, $adjust) = unpack('n', $bytes);



>             [, $adjust] = unpack('n', $bytes);


            $size = 285 + $adjust;

<         } elseif ($size > 30) {
<             list(, $adjust) = unpack('N', "\x00" . $bytes);



>         } else {
>             [, $adjust] = unpack('N', "\x00" . $bytes);


            $size = $adjust + 65821;
        }

        return [$size, $offset + $bytesToRead];
    }


<     private function maybeSwitchByteOrder($bytes)



>     private function maybeSwitchByteOrder(string $bytes): string


    {
        return $this->switchByteOrder ? strrev($bytes) : $bytes;
    }


<     private function isPlatformLittleEndian()



>     private function isPlatformLittleEndian(): bool


    {
        $testint = 0x00FF;
        $packed = pack('S', $testint);

        return $testint === current(unpack('v', $packed));
    }
}