Decoder::decodeBigUint() - Code Metrics - Inspection of "Connect geolite2 to Jetpack EU Cookie Law widget" - Automattic/jetpack - Measure and Improve Code Quality continuously with Scrutinizer

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created 2018-04-24 03:46 UTC

Decoder::decodeBigUint() B

↳ Parent: Decoder

Complexity

Conditions	6
Paths	6

Size

Total Lines	35
Code Lines	21

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	6
eloc	21
nc	6
nop	2
dl	0
loc	35
rs	8.439
c	0
b	0
f	0

<?php

namespace MaxMind\Db\Reader;

class Decoder
{
    private $fileStream;
    private $pointerBase;
    // This is only used for unit testing
    private $pointerTestHack;
    private $switchByteOrder;

    private $types = [
        0 => 'extended',
        1 => 'pointer',
        2 => 'utf8_string',
        3 => 'double',
        4 => 'bytes',
        5 => 'uint16',
        6 => 'uint32',
        7 => 'map',
        8 => 'int32',
        9 => 'uint64',
        10 => 'uint128',
        11 => 'array',
        12 => 'container',
        13 => 'end_marker',
        14 => 'boolean',
        15 => 'float',
    ];

    public function __construct(
        $fileStream,
        $pointerBase = 0,
        $pointerTestHack = false
    ) {
        $this->fileStream = $fileStream;
        $this->pointerBase = $pointerBase;
        $this->pointerTestHack = $pointerTestHack;

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

    public function decode($offset)
    {
        list(, $ctrlByte) = unpack(
            'C',
            Util::read($this->fileStream, $offset, 1)
        );
        $offset++;

        $type = $this->types[$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 === 'pointer') {
            list($pointer, $offset) = $this->decodePointer($ctrlByte, $offset);

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

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

            return [$result, $offset];
        }

        if ($type === 'extended') {
            list(, $nextByte) = unpack(
                'C',
                Util::read($this->fileStream, $offset, 1)
            );

            $typeNum = $nextByte + 7;

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

            $type = $this->types[$typeNum];
            $offset++;
        }

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

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

    private function decodeByType($type, $offset, $size)
    {
        switch ($type) {
            case 'map':
                return $this->decodeMap($size, $offset);
            case 'array':
                return $this->decodeArray($size, $offset);
            case 'boolean':
                return [$this->decodeBoolean($size), $offset];
        }

        $newOffset = $offset + $size;
        $bytes = Util::read($this->fileStream, $offset, $size);
        switch ($type) {
            case 'utf8_string':
                return [$this->decodeString($bytes), $newOffset];
            case 'double':
                $this->verifySize(8, $size);

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

                return [$this->decodeFloat($bytes), $newOffset];
            case 'bytes':
                return [$bytes, $newOffset];
            case 'uint16':
            case 'uint32':
                return [$this->decodeUint($bytes), $newOffset];
            case 'int32':
                return [$this->decodeInt32($bytes), $newOffset];
            case 'uint64':
            case 'uint128':
                return [$this->decodeBigUint($bytes, $size), $newOffset];
            default:
                throw new InvalidDatabaseException(
                    'Unknown or unexpected type: ' . $type
                );
        }
    }

    private function verifySize($expected, $actual)
    {
        if ($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)
    {
        $array = [];

        for ($i = 0; $i < $size; $i++) {
            list($value, $offset) = $this->decode($offset);
            array_push($array, $value);
        }

        return [$array, $offset];
    }

    private function decodeBoolean($size)
    {
        return $size === 0 ? false : true;
    }

    private function decodeDouble($bits)
    {
        // XXX - Assumes IEEE 754 double on platform
        list(, $double) = unpack('d', $this->maybeSwitchByteOrder($bits));

        return $double;
    }

    private function decodeFloat($bits)
    {
        // XXX - Assumes IEEE 754 floats on platform
        list(, $float) = unpack('f', $this->maybeSwitchByteOrder($bits));

        return $float;
    }

    private function decodeInt32($bytes)
    {
        $bytes = $this->zeroPadLeft($bytes, 4);
        list(, $int) = unpack('l', $this->maybeSwitchByteOrder($bytes));

        return $int;
    }

    private function decodeMap($size, $offset)
    {
        $map = [];

        for ($i = 0; $i < $size; $i++) {
            list($key, $offset) = $this->decode($offset);
            list($value, $offset) = $this->decode($offset);
            $map[$key] = $value;
        }

        return [$map, $offset];
    }

    private $pointerValueOffset = [
        1 => 0,
        2 => 2048,
        3 => 526336,
        4 => 0,
    ];

    private function decodePointer($ctrlByte, $offset)
    {
        $pointerSize = (($ctrlByte >> 3) & 0x3) + 1;

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

        $packed = $pointerSize === 4
            ? $buffer
            : (pack('C', $ctrlByte & 0x7)) . $buffer;

        $unpacked = $this->decodeUint($packed);
        $pointer = $unpacked + $this->pointerBase
            + $this->pointerValueOffset[$pointerSize];

        return [$pointer, $offset];
    }

    private function decodeUint($bytes)
    {
        list(, $int) = unpack('N', $this->zeroPadLeft($bytes, 4));

        return $int;
    }

    private function decodeBigUint($bytes, $byteLength)
    {
        $maxUintBytes = log(PHP_INT_MAX, 2) / 8;

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

        $numberOfLongs = ceil($byteLength / 4);
        $paddedLength = $numberOfLongs * 4;
        $paddedBytes = $this->zeroPadLeft($bytes, $paddedLength);
        $unpacked = array_merge(unpack("N$numberOfLongs", $paddedBytes));

        $integer = 0;

        // 2^32
        $twoTo32 = '4294967296';

        foreach ($unpacked as $part) {
            // We only use gmp or bcmath if the final value is too big
            if ($byteLength <= $maxUintBytes) {
                $integer = ($integer << 32) + $part;
            } elseif (extension_loaded('gmp')) {
                $integer = gmp_strval(gmp_add(gmp_mul($integer, $twoTo32), $part));
            } elseif (extension_loaded('bcmath')) {
                $integer = bcadd(bcmul($integer, $twoTo32), $part);
            } else {
                throw new \RuntimeException(
                    'The gmp or bcmath extension must be installed to read this database.'
                );
            }
        }

        return $integer;
    }

    private function decodeString($bytes)
    {
        // XXX - NOOP. As far as I know, the end user has to explicitly set the
        // encoding in PHP. Strings are just bytes.
        return $bytes;
    }

    private function sizeFromCtrlByte($ctrlByte, $offset)
    {
        $size = $ctrlByte & 0x1f;
        $bytesToRead = $size < 29 ? 0 : $size - 28;
        $bytes = Util::read($this->fileStream, $offset, $bytesToRead);
        $decoded = $this->decodeUint($bytes);

        if ($size === 29) {
            $size = 29 + $decoded;
        } elseif ($size === 30) {
            $size = 285 + $decoded;
        } elseif ($size > 30) {
            $size = ($decoded & (0x0FFFFFFF >> (32 - (8 * $bytesToRead))))
                + 65821;
        }

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

    private function zeroPadLeft($content, $desiredLength)
    {
        return str_pad($content, $desiredLength, "\x00", STR_PAD_LEFT);
    }

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

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

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


1			<?php
2
3			namespace MaxMind\Db\Reader;
4
5			class Decoder
6			{
7			private $fileStream;
8			private $pointerBase;
9			// This is only used for unit testing
10			private $pointerTestHack;
11			private $switchByteOrder;
12
13			private $types = [
14			0 => 'extended',
15			1 => 'pointer',
16			2 => 'utf8_string',
17			3 => 'double',
18			4 => 'bytes',
19			5 => 'uint16',
20			6 => 'uint32',
21			7 => 'map',
22			8 => 'int32',
23			9 => 'uint64',
24			10 => 'uint128',
25			11 => 'array',
26			12 => 'container',
27			13 => 'end_marker',
28			14 => 'boolean',
29			15 => 'float',
30			];
31
32			public function __construct(
33			$fileStream,
34			$pointerBase = 0,
35			$pointerTestHack = false
36			) {
37			$this->fileStream = $fileStream;
38			$this->pointerBase = $pointerBase;
39			$this->pointerTestHack = $pointerTestHack;
40
41			$this->switchByteOrder = $this->isPlatformLittleEndian();
42			}
43
44			public function decode($offset)
45			{
46			list(, $ctrlByte) = unpack(
47			'C',
48			Util::read($this->fileStream, $offset, 1)
49			);
50			$offset++;
51
52			$type = $this->types[$ctrlByte >> 5];
53
54			// Pointers are a special case, we don't read the next $size bytes, we
55			// use the size to determine the length of the pointer and then follow
56			// it.
57			if ($type === 'pointer') {
58			list($pointer, $offset) = $this->decodePointer($ctrlByte, $offset);
59
60			// for unit testing
61			if ($this->pointerTestHack) {
62			return [$pointer];
63			}
64
65			list($result) = $this->decode($pointer);
66
67			return [$result, $offset];
68			}
69
70			if ($type === 'extended') {
71			list(, $nextByte) = unpack(
72			'C',
73			Util::read($this->fileStream, $offset, 1)
74			);
75
76			$typeNum = $nextByte + 7;
77
78			if ($typeNum < 8) {
79			throw new InvalidDatabaseException(
80			'Something went horribly wrong in the decoder. An extended type '
81			. 'resolved to a type number < 8 ('
82			. $this->types[$typeNum]
83			. ')'
84			);
85			}
86
87			$type = $this->types[$typeNum];
88			$offset++;
89			}
90
91			list($size, $offset) = $this->sizeFromCtrlByte($ctrlByte, $offset);
92
93			return $this->decodeByType($type, $offset, $size);
94			}
95
96			private function decodeByType($type, $offset, $size)
97			{
98			switch ($type) {
99			case 'map':
100			return $this->decodeMap($size, $offset);
101			case 'array':
102			return $this->decodeArray($size, $offset);
103			case 'boolean':
104			return [$this->decodeBoolean($size), $offset];
105			}
106
107			$newOffset = $offset + $size;
108			$bytes = Util::read($this->fileStream, $offset, $size);
109			switch ($type) {
110			case 'utf8_string':
111			return [$this->decodeString($bytes), $newOffset];
112			case 'double':
113			$this->verifySize(8, $size);
114
115			return [$this->decodeDouble($bytes), $newOffset];
116			case 'float':
117			$this->verifySize(4, $size);
118
119			return [$this->decodeFloat($bytes), $newOffset];
120			case 'bytes':
121			return [$bytes, $newOffset];
122			case 'uint16':
123			case 'uint32':
124			return [$this->decodeUint($bytes), $newOffset];
125			case 'int32':
126			return [$this->decodeInt32($bytes), $newOffset];
127			case 'uint64':
128			case 'uint128':
129			return [$this->decodeBigUint($bytes, $size), $newOffset];
130			default:
131			throw new InvalidDatabaseException(
132			'Unknown or unexpected type: ' . $type
133			);
134			}
135			}
136
137			private function verifySize($expected, $actual)
138			{
139			if ($expected !== $actual) {
140			throw new InvalidDatabaseException(
141			"The MaxMind DB file's data section contains bad data (unknown data type or corrupt data)"
142			);
143			}
144			}
145
146			private function decodeArray($size, $offset)
147			{
148			$array = [];
149
150			for ($i = 0; $i < $size; $i++) {
151			list($value, $offset) = $this->decode($offset);
152			array_push($array, $value);
153			}
154
155			return [$array, $offset];
156			}
157
158			private function decodeBoolean($size)
159			{
160			return $size === 0 ? false : true;
161			}
162
163			private function decodeDouble($bits)
164			{
165			// XXX - Assumes IEEE 754 double on platform
166			list(, $double) = unpack('d', $this->maybeSwitchByteOrder($bits));
167
168			return $double;
169			}
170
171			private function decodeFloat($bits)
172			{
173			// XXX - Assumes IEEE 754 floats on platform
174			list(, $float) = unpack('f', $this->maybeSwitchByteOrder($bits));
175
176			return $float;
177			}
178
179			private function decodeInt32($bytes)
180			{
181			$bytes = $this->zeroPadLeft($bytes, 4);
182			list(, $int) = unpack('l', $this->maybeSwitchByteOrder($bytes));
183
184			return $int;
185			}
186
187			private function decodeMap($size, $offset)
188			{
189			$map = [];
190
191			for ($i = 0; $i < $size; $i++) {
192			list($key, $offset) = $this->decode($offset);
193			list($value, $offset) = $this->decode($offset);
194			$map[$key] = $value;
195			}
196
197			return [$map, $offset];
198			}
199
200			private $pointerValueOffset = [
201			1 => 0,
202			2 => 2048,
203			3 => 526336,
204			4 => 0,
205			];
206
207			private function decodePointer($ctrlByte, $offset)
208			{
209			$pointerSize = (($ctrlByte >> 3) & 0x3) + 1;
210
211			$buffer = Util::read($this->fileStream, $offset, $pointerSize);
212			$offset = $offset + $pointerSize;
213
214			$packed = $pointerSize === 4
215			? $buffer
216			: (pack('C', $ctrlByte & 0x7)) . $buffer;
217
218			$unpacked = $this->decodeUint($packed);
219			$pointer = $unpacked + $this->pointerBase
220			+ $this->pointerValueOffset[$pointerSize];
221
222			return [$pointer, $offset];
223			}
224
225			private function decodeUint($bytes)
226			{
227			list(, $int) = unpack('N', $this->zeroPadLeft($bytes, 4));
228
229			return $int;
230			}
231
232			private function decodeBigUint($bytes, $byteLength)
233			{
234			$maxUintBytes = log(PHP_INT_MAX, 2) / 8;
235
236			if ($byteLength === 0) {
237			return 0;
238			}
239
240			$numberOfLongs = ceil($byteLength / 4);
241			$paddedLength = $numberOfLongs * 4;
242			$paddedBytes = $this->zeroPadLeft($bytes, $paddedLength);
243			$unpacked = array_merge(unpack("N$numberOfLongs", $paddedBytes));
244
245			$integer = 0;
246
247			// 2^32
248			$twoTo32 = '4294967296';
249
250			foreach ($unpacked as $part) {
251			// We only use gmp or bcmath if the final value is too big
252			if ($byteLength <= $maxUintBytes) {
253			$integer = ($integer << 32) + $part;
254			} elseif (extension_loaded('gmp')) {
255			$integer = gmp_strval(gmp_add(gmp_mul($integer, $twoTo32), $part));
256			} elseif (extension_loaded('bcmath')) {
257			$integer = bcadd(bcmul($integer, $twoTo32), $part);
258			} else {
259			throw new \RuntimeException(
260			'The gmp or bcmath extension must be installed to read this database.'
261			);
262			}
263			}
264
265			return $integer;
266			}
267
268			private function decodeString($bytes)
269			{
270			// XXX - NOOP. As far as I know, the end user has to explicitly set the
271			// encoding in PHP. Strings are just bytes.
272			return $bytes;
273			}
274
275			private function sizeFromCtrlByte($ctrlByte, $offset)
276			{
277			$size = $ctrlByte & 0x1f;
278			$bytesToRead = $size < 29 ? 0 : $size - 28;
279			$bytes = Util::read($this->fileStream, $offset, $bytesToRead);
280			$decoded = $this->decodeUint($bytes);
281
282			if ($size === 29) {
283			$size = 29 + $decoded;
284			} elseif ($size === 30) {
285			$size = 285 + $decoded;
286			} elseif ($size > 30) {
287			$size = ($decoded & (0x0FFFFFFF >> (32 - (8 * $bytesToRead))))
288			+ 65821;
289			}
290
291			return [$size, $offset + $bytesToRead];
292			}
293
294			private function zeroPadLeft($content, $desiredLength)
295			{
296			return str_pad($content, $desiredLength, "\x00", STR_PAD_LEFT);
297			}
298
299			private function maybeSwitchByteOrder($bytes)
300			{
301			return $this->switchByteOrder ? strrev($bytes) : $bytes;
302			}
303
304			private function isPlatformLittleEndian()
305			{
306			$testint = 0x00FF;
307			$packed = pack('S', $testint);
308
309			return $testint === current(unpack('v', $packed));
310			}
311			}
312

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Decoder::decodeBigUint() B

Complexity

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