Decoder.php
2 weeks ago
InvalidDatabaseException.php
2 years ago
Metadata.php
2 weeks ago
Util.php
2 years ago
Decoder.php
333 lines
| 1 | <?php |
| 2 | |
| 3 | declare (strict_types=1); |
| 4 | namespace IAWPSCOPED\MaxMind\Db\Reader; |
| 5 | |
| 6 | // @codingStandardsIgnoreLine |
| 7 | /** @internal */ |
| 8 | class Decoder |
| 9 | { |
| 10 | /** |
| 11 | * @var resource |
| 12 | */ |
| 13 | private $fileStream; |
| 14 | /** |
| 15 | * @var int |
| 16 | */ |
| 17 | private $pointerBase; |
| 18 | /** |
| 19 | * This is only used for unit testing. |
| 20 | * |
| 21 | * @var bool |
| 22 | */ |
| 23 | private $pointerTestHack; |
| 24 | /** |
| 25 | * @var bool |
| 26 | */ |
| 27 | private $switchByteOrder; |
| 28 | private const _EXTENDED = 0; |
| 29 | private const _POINTER = 1; |
| 30 | private const _UTF8_STRING = 2; |
| 31 | private const _DOUBLE = 3; |
| 32 | private const _BYTES = 4; |
| 33 | private const _UINT16 = 5; |
| 34 | private const _UINT32 = 6; |
| 35 | private const _MAP = 7; |
| 36 | private const _INT32 = 8; |
| 37 | private const _UINT64 = 9; |
| 38 | private const _UINT128 = 10; |
| 39 | private const _ARRAY = 11; |
| 40 | // 12 is the container type |
| 41 | // 13 is the end marker type |
| 42 | private const _BOOLEAN = 14; |
| 43 | private const _FLOAT = 15; |
| 44 | /** |
| 45 | * @param resource $fileStream |
| 46 | */ |
| 47 | public function __construct($fileStream, int $pointerBase = 0, bool $pointerTestHack = \false) |
| 48 | { |
| 49 | $this->fileStream = $fileStream; |
| 50 | $this->pointerBase = $pointerBase; |
| 51 | $this->pointerTestHack = $pointerTestHack; |
| 52 | $this->switchByteOrder = $this->isPlatformLittleEndian(); |
| 53 | } |
| 54 | /** |
| 55 | * @return array<mixed> |
| 56 | */ |
| 57 | public function decode(int $offset) : array |
| 58 | { |
| 59 | $ctrlByte = \ord(Util::read($this->fileStream, $offset, 1)); |
| 60 | ++$offset; |
| 61 | $type = $ctrlByte >> 5; |
| 62 | // Pointers are a special case, we don't read the next $size bytes, we |
| 63 | // use the size to determine the length of the pointer and then follow |
| 64 | // it. |
| 65 | if ($type === self::_POINTER) { |
| 66 | [$pointer, $offset] = $this->decodePointer($ctrlByte, $offset); |
| 67 | // for unit testing |
| 68 | if ($this->pointerTestHack) { |
| 69 | return [$pointer]; |
| 70 | } |
| 71 | [$result] = $this->decode($pointer); |
| 72 | return [$result, $offset]; |
| 73 | } |
| 74 | if ($type === self::_EXTENDED) { |
| 75 | $nextByte = \ord(Util::read($this->fileStream, $offset, 1)); |
| 76 | $type = $nextByte + 7; |
| 77 | if ($type < 8) { |
| 78 | throw new InvalidDatabaseException('Something went horribly wrong in the decoder. An extended type ' . 'resolved to a type number < 8 (' . $type . ')'); |
| 79 | } |
| 80 | ++$offset; |
| 81 | } |
| 82 | [$size, $offset] = $this->sizeFromCtrlByte($ctrlByte, $offset); |
| 83 | return $this->decodeByType($type, $offset, $size); |
| 84 | } |
| 85 | /** |
| 86 | * @param int<0, max> $size |
| 87 | * |
| 88 | * @return array{0:mixed, 1:int} |
| 89 | */ |
| 90 | private function decodeByType(int $type, int $offset, int $size) : array |
| 91 | { |
| 92 | switch ($type) { |
| 93 | case self::_MAP: |
| 94 | return $this->decodeMap($size, $offset); |
| 95 | case self::_ARRAY: |
| 96 | return $this->decodeArray($size, $offset); |
| 97 | case self::_BOOLEAN: |
| 98 | return [$this->decodeBoolean($size), $offset]; |
| 99 | } |
| 100 | $newOffset = $offset + $size; |
| 101 | $bytes = Util::read($this->fileStream, $offset, $size); |
| 102 | switch ($type) { |
| 103 | case self::_BYTES: |
| 104 | case self::_UTF8_STRING: |
| 105 | return [$bytes, $newOffset]; |
| 106 | case self::_DOUBLE: |
| 107 | $this->verifySize(8, $size); |
| 108 | return [$this->decodeDouble($bytes), $newOffset]; |
| 109 | case self::_FLOAT: |
| 110 | $this->verifySize(4, $size); |
| 111 | return [$this->decodeFloat($bytes), $newOffset]; |
| 112 | case self::_INT32: |
| 113 | return [$this->decodeInt32($bytes, $size), $newOffset]; |
| 114 | case self::_UINT16: |
| 115 | case self::_UINT32: |
| 116 | case self::_UINT64: |
| 117 | case self::_UINT128: |
| 118 | return [$this->decodeUint($bytes, $size), $newOffset]; |
| 119 | default: |
| 120 | throw new InvalidDatabaseException('Unknown or unexpected type: ' . $type); |
| 121 | } |
| 122 | } |
| 123 | private function verifySize(int $expected, int $actual) : void |
| 124 | { |
| 125 | if ($expected !== $actual) { |
| 126 | throw new InvalidDatabaseException("The MaxMind DB file's data section contains bad data (unknown data type or corrupt data)"); |
| 127 | } |
| 128 | } |
| 129 | /** |
| 130 | * @return array{0:array<mixed>, 1:int} |
| 131 | */ |
| 132 | private function decodeArray(int $size, int $offset) : array |
| 133 | { |
| 134 | $array = []; |
| 135 | for ($i = 0; $i < $size; ++$i) { |
| 136 | [$value, $offset] = $this->decode($offset); |
| 137 | $array[] = $value; |
| 138 | } |
| 139 | return [$array, $offset]; |
| 140 | } |
| 141 | private function decodeBoolean(int $size) : bool |
| 142 | { |
| 143 | return $size !== 0; |
| 144 | } |
| 145 | private function decodeDouble(string $bytes) : float |
| 146 | { |
| 147 | // This assumes IEEE 754 doubles, but most (all?) modern platforms |
| 148 | // use them. |
| 149 | $rc = \unpack('E', $bytes); |
| 150 | if ($rc === \false) { |
| 151 | throw new InvalidDatabaseException('Could not unpack a double value from the given bytes.'); |
| 152 | } |
| 153 | [, $double] = $rc; |
| 154 | return $double; |
| 155 | } |
| 156 | private function decodeFloat(string $bytes) : float |
| 157 | { |
| 158 | // This assumes IEEE 754 floats, but most (all?) modern platforms |
| 159 | // use them. |
| 160 | $rc = \unpack('G', $bytes); |
| 161 | if ($rc === \false) { |
| 162 | throw new InvalidDatabaseException('Could not unpack a float value from the given bytes.'); |
| 163 | } |
| 164 | [, $float] = $rc; |
| 165 | return $float; |
| 166 | } |
| 167 | private function decodeInt32(string $bytes, int $size) : int |
| 168 | { |
| 169 | switch ($size) { |
| 170 | case 0: |
| 171 | return 0; |
| 172 | case 1: |
| 173 | case 2: |
| 174 | case 3: |
| 175 | $bytes = \str_pad($bytes, 4, "\x00", \STR_PAD_LEFT); |
| 176 | break; |
| 177 | case 4: |
| 178 | break; |
| 179 | default: |
| 180 | throw new InvalidDatabaseException("The MaxMind DB file's data section contains bad data (unknown data type or corrupt data)"); |
| 181 | } |
| 182 | $rc = \unpack('l', $this->maybeSwitchByteOrder($bytes)); |
| 183 | if ($rc === \false) { |
| 184 | throw new InvalidDatabaseException('Could not unpack a 32bit integer value from the given bytes.'); |
| 185 | } |
| 186 | [, $int] = $rc; |
| 187 | return $int; |
| 188 | } |
| 189 | /** |
| 190 | * @return array{0:array<string, mixed>, 1:int} |
| 191 | */ |
| 192 | private function decodeMap(int $size, int $offset) : array |
| 193 | { |
| 194 | $map = []; |
| 195 | for ($i = 0; $i < $size; ++$i) { |
| 196 | [$key, $offset] = $this->decode($offset); |
| 197 | [$value, $offset] = $this->decode($offset); |
| 198 | $map[$key] = $value; |
| 199 | } |
| 200 | return [$map, $offset]; |
| 201 | } |
| 202 | /** |
| 203 | * @return array{0:int, 1:int} |
| 204 | */ |
| 205 | private function decodePointer(int $ctrlByte, int $offset) : array |
| 206 | { |
| 207 | $pointerSize = ($ctrlByte >> 3 & 0x3) + 1; |
| 208 | $buffer = Util::read($this->fileStream, $offset, $pointerSize); |
| 209 | $offset += $pointerSize; |
| 210 | switch ($pointerSize) { |
| 211 | case 1: |
| 212 | $packed = \chr($ctrlByte & 0x7) . $buffer; |
| 213 | $rc = \unpack('n', $packed); |
| 214 | if ($rc === \false) { |
| 215 | throw new InvalidDatabaseException('Could not unpack an unsigned short value from the given bytes (pointerSize is 1).'); |
| 216 | } |
| 217 | [, $pointer] = $rc; |
| 218 | $pointer += $this->pointerBase; |
| 219 | break; |
| 220 | case 2: |
| 221 | $packed = "\x00" . \chr($ctrlByte & 0x7) . $buffer; |
| 222 | $rc = \unpack('N', $packed); |
| 223 | if ($rc === \false) { |
| 224 | throw new InvalidDatabaseException('Could not unpack an unsigned long value from the given bytes (pointerSize is 2).'); |
| 225 | } |
| 226 | [, $pointer] = $rc; |
| 227 | $pointer += $this->pointerBase + 2048; |
| 228 | break; |
| 229 | case 3: |
| 230 | $packed = \chr($ctrlByte & 0x7) . $buffer; |
| 231 | // It is safe to use 'N' here, even on 32 bit machines as the |
| 232 | // first bit is 0. |
| 233 | $rc = \unpack('N', $packed); |
| 234 | if ($rc === \false) { |
| 235 | throw new InvalidDatabaseException('Could not unpack an unsigned long value from the given bytes (pointerSize is 3).'); |
| 236 | } |
| 237 | [, $pointer] = $rc; |
| 238 | $pointer += $this->pointerBase + 526336; |
| 239 | break; |
| 240 | case 4: |
| 241 | // We cannot use unpack here as we might overflow on 32 bit |
| 242 | // machines |
| 243 | $pointerOffset = $this->decodeUint($buffer, $pointerSize); |
| 244 | $pointerBase = $this->pointerBase; |
| 245 | if (\PHP_INT_MAX - $pointerBase >= $pointerOffset) { |
| 246 | $pointer = $pointerOffset + $pointerBase; |
| 247 | } else { |
| 248 | throw new \RuntimeException('The database offset is too large to be represented on your platform.'); |
| 249 | } |
| 250 | break; |
| 251 | default: |
| 252 | throw new InvalidDatabaseException('Unexpected pointer size ' . $pointerSize); |
| 253 | } |
| 254 | return [$pointer, $offset]; |
| 255 | } |
| 256 | // @phpstan-ignore-next-line |
| 257 | private function decodeUint(string $bytes, int $byteLength) |
| 258 | { |
| 259 | if ($byteLength === 0) { |
| 260 | return 0; |
| 261 | } |
| 262 | // PHP integers are signed. PHP_INT_SIZE - 1 is the number of |
| 263 | // complete bytes that can be converted to an integer. However, |
| 264 | // we can convert another byte if the leading bit is zero. |
| 265 | $useRealInts = $byteLength <= \PHP_INT_SIZE - 1 || $byteLength === \PHP_INT_SIZE && (\ord($bytes[0]) & 0x80) === 0; |
| 266 | if ($useRealInts) { |
| 267 | $integer = 0; |
| 268 | for ($i = 0; $i < $byteLength; ++$i) { |
| 269 | $part = \ord($bytes[$i]); |
| 270 | $integer = ($integer << 8) + $part; |
| 271 | } |
| 272 | return $integer; |
| 273 | } |
| 274 | // We only use gmp or bcmath if the final value is too big |
| 275 | $integerAsString = '0'; |
| 276 | for ($i = 0; $i < $byteLength; ++$i) { |
| 277 | $part = \ord($bytes[$i]); |
| 278 | if (\extension_loaded('gmp')) { |
| 279 | $integerAsString = \gmp_strval(\gmp_add(\gmp_mul($integerAsString, '256'), $part)); |
| 280 | } elseif (\extension_loaded('bcmath')) { |
| 281 | $integerAsString = \bcadd(\bcmul($integerAsString, '256'), (string) $part); |
| 282 | } else { |
| 283 | throw new \RuntimeException('The gmp or bcmath extension must be installed to read this database.'); |
| 284 | } |
| 285 | } |
| 286 | return $integerAsString; |
| 287 | } |
| 288 | /** |
| 289 | * @return array{0:int, 1:int} |
| 290 | */ |
| 291 | private function sizeFromCtrlByte(int $ctrlByte, int $offset) : array |
| 292 | { |
| 293 | $size = $ctrlByte & 0x1f; |
| 294 | if ($size < 29) { |
| 295 | return [$size, $offset]; |
| 296 | } |
| 297 | $bytesToRead = $size - 28; |
| 298 | $bytes = Util::read($this->fileStream, $offset, $bytesToRead); |
| 299 | if ($size === 29) { |
| 300 | $size = 29 + \ord($bytes); |
| 301 | } elseif ($size === 30) { |
| 302 | $rc = \unpack('n', $bytes); |
| 303 | if ($rc === \false) { |
| 304 | throw new InvalidDatabaseException('Could not unpack an unsigned short value from the given bytes.'); |
| 305 | } |
| 306 | [, $adjust] = $rc; |
| 307 | $size = 285 + $adjust; |
| 308 | } else { |
| 309 | $rc = \unpack('N', "\x00" . $bytes); |
| 310 | if ($rc === \false) { |
| 311 | throw new InvalidDatabaseException('Could not unpack an unsigned long value from the given bytes.'); |
| 312 | } |
| 313 | [, $adjust] = $rc; |
| 314 | $size = $adjust + 65821; |
| 315 | } |
| 316 | return [$size, $offset + $bytesToRead]; |
| 317 | } |
| 318 | private function maybeSwitchByteOrder(string $bytes) : string |
| 319 | { |
| 320 | return $this->switchByteOrder ? \strrev($bytes) : $bytes; |
| 321 | } |
| 322 | private function isPlatformLittleEndian() : bool |
| 323 | { |
| 324 | $testint = 0xff; |
| 325 | $packed = \pack('S', $testint); |
| 326 | $rc = \unpack('v', $packed); |
| 327 | if ($rc === \false) { |
| 328 | throw new InvalidDatabaseException('Could not unpack an unsigned short value from the given bytes.'); |
| 329 | } |
| 330 | return $testint === \current($rc); |
| 331 | } |
| 332 | } |
| 333 |