Last active
December 4, 2019 17:55
-
-
Save jmwebservices/3cd9cb273ec52f835a6dd13d62b2bc76 to your computer and use it in GitHub Desktop.
Show that strpos() on a chunk using substr() is more efficient than on the whole for large strings.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| function find( ?string $string ) | |
| { | |
| static $found = 0; | |
| if( null === $string ) return $found; | |
| $found += 0 === strpos( $string, BOM_UTF8 ); | |
| $found += 0 === strpos( $string, BOM_UTF16_BE ); | |
| $found += 0 === strpos( $string, BOM_UTF16_LE ); | |
| $found += 0 === strpos( $string, BOM_UTF32_BE ); | |
| $found += 0 === strpos( $string, BOM_UTF32_LE ); | |
| } | |
| function random_string( int $length = 32, string $pool = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz', string $encoding = null ) : string | |
| { | |
| if( $length === 0 ) | |
| return ''; | |
| if( $length < 0 ) | |
| throw new DomainException( 'Length must be >= 0.' ); | |
| if( $pool === '' ) | |
| throw new DomainException( 'Pool cannot be an empty string.' ); | |
| $encoding = (array) $encoding; | |
| $maxKey = mb_strlen( $pool, ...$encoding ); | |
| if( $maxKey === false ) | |
| throw new DomainException( 'Invalid encoding specified.' ); | |
| for( --$maxKey, $random = ''; $length-- ; ) | |
| $random .= mb_substr( $pool, random_int( 0, $maxKey ), 1, ...$encoding ); | |
| return $random; | |
| } | |
| const BOM_UTF8 = "\xEF\xBB\xBF"; | |
| const BOM_UTF16_BE = "\xFE\xFF"; | |
| const BOM_UTF16_LE = "\xFF\xFE"; | |
| const BOM_UTF32_BE = "\x00\x00\xFE\xFF"; | |
| const BOM_UTF32_LE = "\xFF\xFE\x00\x00"; | |
| $bomLess = random_string( 1024 * 1024 ); | |
| $tests = 1; | |
| $full = -hrtime( true ); | |
| for( $i = 0; $i < $tests; ++$i ) | |
| find( $bomLess ); | |
| $full += hrtime( true ); | |
| $chunk = -hrtime( true ); | |
| for( $i = 0; $i < $tests; ++$i ) | |
| find( substr( $bomLess, 0, 4 ) ); | |
| $chunk += hrtime( true ); | |
| var_dump( | |
| 'Found: ' . find( null ), | |
| "Finding on full took: $full", | |
| "Finding on chunk took: $chunk" | |
| ); |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment