QuickHashStringIntHash::loadFromFile
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QuickHashStringIntHash::loadFromFile — This factory method creates a hash from a file
Description
$filename, int $size = 0, int $options = 0): QuickHashStringIntHash
This factory method creates a new hash from a definition file on disk. The
file format consists of a signature 'QH\0x21\0', the number of elements as
a 32 bit signed integer in system Endianness, an unsigned 32 bit integer
containing the number of element data to follow in characters. This element
data contains all the strings. The follows another signed 32 bit integer
containing the number of bucket lists. After the header and the strings,
the elements follow. They are ordered by bucket list so that the keys don't
have to be hashed in order to restore the hash. For each bucket list, the
following information is stored (all as 32 bit integers): the bucket list
index, the number of elements in that list, and then in pairs of two
unsigned 32 bit integers the elements, where the first one is the index
into the string list containing the keys, and the second one the value. An
example could be:
Example #1 QuickHash StringIntHash file format
00000000 51 48 21 00 02 00 00 00 09 00 00 00 40 00 00 00 |QH!.........@...| 00000010 4f 4e 45 00 4e 49 4e 45 00 07 00 00 00 01 00 00 |ONE.NINE........| 00000020 00 00 00 00 00 01 00 00 00 2f 00 00 00 01 00 00 |........./......| 00000030 00 04 00 00 00 03 00 00 00 |.........| 00000039
Example #2 QuickHash IntHash file format
header signature ('QH'; key type: 2; value type: 1; filler: \0x00)
00000000 51 48 21 00
number of elements:
00000004 02 00 00 00
length of string values (9 characters):
00000008 09 00 00 00
number of hash bucket lists (this is configured for hashes as argument to the
constructor normally, 64 in this case):
0000000C 40 00 00 00
string values:
00000010 4f 4e 45 00 4e 49 4e 45 00
bucket lists:
bucket list 1 (with key 7, and 1 element):
header:
07 00 00 00 01 00 00 00
elements (key index: 0 ('ONE'), value = 0):
00 00 00 00 01 00 00 00
bucket list 2 (with key 0x2f, and 1 element):
header:
2f 00 00 00 01 00 00 00
elements (key index: 4 ('NINE'), value = 3):
04 00 00 00 03 00 00 00
Parameters
-
filename -
The filename of the file to read the hash from.
-
size -
The amount of bucket lists to configure. The number you pass in will be automatically rounded up to the next power of two. It is also automatically limited from
4to4194304. -
options -
The same options that the class' constructor takes; except that the size option is ignored. It is read from the file format (unlike the QuickHashIntHash and QuickHashIntStringHash classes, where it is automatically calculated from the number of entries in the hash.)
Return Values
Returns a new QuickHashStringIntHash.
Examples
Example #3 QuickHashStringIntHash::loadFromFile() example
<?php
$file = dirname( __FILE__ ) . "/simple.hash.string";
$hash = QuickHashStringIntHash::loadFromFile(
$file,
QuickHashStringIntHash::DO_NOT_USE_ZEND_ALLOC
);
foreach( range( 0, 0x0f ) as $key )
{
$i = 48712 + $key * 1631;
$k = base_convert( $i, 10, 36 );
echo $k, ' => ', $hash->get( $k ), "\n";
}
?>The above example will output something similar to:
11l4 => 48712 12uf => 50343 143q => 51974 15d1 => 53605 16mc => 55236 17vn => 56867 194y => 58498 1ae9 => 60129 1bnk => 61760 1cwv => 63391 1e66 => 65022 1ffh => 66653 1gos => 68284 1hy3 => 69915 1j7e => 71546 1kgp => 73177
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