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pradosoft#835 TBitHelper::crc32 for continued running crc32 computation.
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PHPs crc32 only works on a $string.  this is a multi-tool.  it can crc32 a file path, or part of a file, and will work on streams when given a stream (similar to `stream_get_contents($stream, $length, $offset)` but `[$stream, $length, $offset]` is fed as $string).

One of the key features is that an existing $crc32 can be fed to this method and it will continue the CRC32 computation as if the new $string data (any source: string, file, file part, or stream) were appended to the prior data.
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@belisoful
belisoful committed May 25, 2023
1 parent 9f596b9 commit 55a6b89
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136 changes: 136 additions & 0 deletions framework/Util/Helpers/TBitHelper.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -121,6 +121,142 @@ public static function hasLongLong(): bool
return PHP_INT_SIZE >= 8;
}

/**
* This is a CRC32 replacement multi-tool. This acts exactly as crc32 with the
* added functionality that it accepts file paths (when $crc = true) which computes
* the CRC32 of the file. This also accepts a $crc computed from existing data and
* continues to update the $crc with new data form $string as if $string were appended.
*
* If an array is passed in $string, [0] is the string data, filepath, or stream
* resource, element [1] is the size to read, and element [2] is the startOffset.
* If an array is passed, $crc = true still means that the $string is a FilePath.
* If the $string is a stream-resource, it reads until fgetc returns false or '',
* or size is hit.
*
* If using this on a file (with $crc = true) then $crc2 can be used for the existing
* crc32 for continued computation.
*
* A continued CRC32 can also be generated with HashContext using {@link hash_init},
* {@link hash_update}, and {@link hash_update_stream}, and {@link hash_final}.
* @param mixed $string String of Data, File Path, Stream Resource, or array.
* An Array format is [0] => String Data, File Path, or Stream Resource, [1] is
* the total size to read, and [2] is the startOffset.
* @param bool|int $crc The running CRC32 to continue calculating. When true,
* this expects $string to be a File Path rather than data. Default 0 for normal
* crc32 function without any prior running data.
* @param ?int $crc2 The existing CRC to update when specifying $string as a file
* (with $crc = true). Default null for new initial $crc for a file.
*/
public static function crc32(mixed $string, bool|int $crc = 0, ?int $crc2 = null): false|int
{
static $crc_table = [
0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
];
$length = null;
$startOffset = 0;
$close = false;
if (is_array($string)) {
$startOffset = $string[2] ?? $string['offset'] ?? 0;
$length = $string[1] ?? $string['length'] ?? null;
$string = $string[0] ?? $string['source'] ?? null;
}
if ($crc === false) {
$crc = $crc2 === null ? 0 : $crc2;
}
if (is_string($string)) {
if (is_int($crc)) {
if ($length !== null || $startOffset) {
$string = substr($string, $startOffset, $length);
}
if ($crc === 0) {
return crc32($string);
}
$crc ^= 0xFFFFFFFF;
$length = strlen($string);
for ($i = 0; $i < $length; $i++) {
$crc = (($crc >> 8) & 0x00FFFFFF) ^ $crc_table[($crc & 0xFF) ^ ord($string[$i])];
}
$crc ^= 0xFFFFFFFF;
return $crc;
} elseif (realpath($string) || preg_match('/^[-+\.\w\d]{1,20}\:\/\//i', $string)) {
if ($length === null && !$startOffset && !$crc2) {
$hash = hash_file('crc32b', $string, true);
$value = unpack('N', $hash)[1];
if(PHP_INT_SIZE === 4 && $value > self::PHP_INT32_MAX) {
$value = (int) ($value - self::PHP_INT32_UMAX - 1);
}
return $value;
}
$string = fopen($string, 'rb');
if (!$string) {
return false;
}
$close = true;
}
}
if (is_resource($string) && get_resource_type($string) === 'stream') {
if ($crc === true) {
$crc = $crc2 === null ? 0 : $crc2;
}
if ($startOffset) {
$meta = stream_get_meta_data($string);
if ($meta['seekable']) {
fseek($string, $startOffset);
} else {
fread($string, $startOffset);
}
}
$crc ^= 0xFFFFFFFF;
while($length === null || $length > 0) {
$d = fgetc($string);
if ($d === false || strlen($d) === 0) {
break;
}
$crc = (($crc >> 8) & 0x00FFFFFF) ^ $crc_table[($crc & 0xFF) ^ ord($d)];
if ($length !== null) {
$length--;
}
}
$crc ^= 0xFFFFFFFF;
if ($close) {
fclose($string);
}
return $length === null || $length === 0 ? $crc : false;
}
return false;
}

/**
* This returns true with all negative floats, including -0.0. Normally "$float < 0"
* will not include -0.0, where this function does include -0.0.
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51 changes: 51 additions & 0 deletions tests/unit/Util/Helpers/TBitHelperTest.php
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,57 @@ public function testHasLongLong()
self::assertEquals(PHP_INT_SIZE >= 8, TBitHelper::hasLongLong());
}

public function testCrc32()
{
self::assertEquals(crc32(''), TBitHelper::crc32(''));
self::assertEquals(crc32(''), TBitHelper::crc32('', false));
self::assertEquals(crc32('test'), $crc = TBitHelper::crc32('test'));
self::assertEquals(crc32('1234'), TBitHelper::crc32('1234', false));
self::assertEquals(crc32('test1234'), TBitHelper::crc32('1234', $crc));
self::assertEquals(crc32('test1234'), TBitHelper::crc32('1234', false, $crc));
self::assertEquals(crc32('0123456789'), TBitHelper::crc32(['0123456789', null]));
self::assertEquals(crc32('012'), TBitHelper::crc32(['0123456789', 3]));
self::assertEquals(crc32('3456789'), TBitHelper::crc32(['0123456789', null, 3]));
self::assertEquals(crc32('345'), TBitHelper::crc32(['0123456789', 3, 3]));

$filename = realpath(__DIR__ . '/../../Web/data/pradoheader.gif');
$fileContents = file_get_contents($filename);

self::assertEquals($fileCrc32 = crc32($fileContents), TBitHelper::crc32($filename, true));
self::assertEquals(crc32(substr($fileContents, 0, 10)), TBitHelper::crc32([$filename, 10], true));
self::assertEquals(crc32(substr($fileContents, 2)), TBitHelper::crc32([$filename, null, 2], true));
self::assertEquals(crc32(substr($fileContents, 2, 10)), TBitHelper::crc32([$filename, 10, 2], true));
self::assertEquals(crc32('data' . substr($fileContents, 2, 10)), TBitHelper::crc32([$filename, 10, 2], true, crc32('data')));

$handle = fopen($filename, 'rb');
self::assertEquals($fileCrc32, TBitHelper::crc32($handle, true));
fclose($handle);

$handle = fopen($filename, 'rb');
self::assertEquals($fileCrc32, TBitHelper::crc32($handle));
fclose($handle);

$handle = fopen($filename, 'rb');
self::assertEquals($fileCrc32, TBitHelper::crc32($handle, false));
fclose($handle);

$handle = fopen($filename, 'rb');
self::assertEquals(crc32(substr($fileContents, 0, 10)), TBitHelper::crc32([$handle, 10]));
fclose($handle);

$handle = fopen($filename, 'rb');
self::assertEquals(crc32(substr($fileContents, 2)), TBitHelper::crc32([$handle, null, 2]));
fclose($handle);

$handle = fopen($filename, 'rb');
self::assertEquals(crc32(substr($fileContents, 2, 10)), TBitHelper::crc32([$handle, 10, 2]));
fclose($handle);

$handle = fopen($filename, 'rb');
self::assertEquals(crc32(substr($fileContents, 2, 10)), TBitHelper::crc32([$handle, 10, 2]));
fclose($handle);
}

public function testIsNegativeFloat()
{
self::assertEquals(false, TBitHelper::isNegativeFloat(0.0));
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