includes/Fallback.php

   1 <?php
   2
   3 /**
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  17  * http://www.gnu.org/copyleft/gpl.html
  18  *
  19  */
  20
  21 /**
  22  * Fallback functions for PHP installed without mbstring support
  23  */
  24 class Fallback {
  25
  26         /**
  27          * @param $from
  28          * @param $to
  29          * @param $string
  30          * @return string
  31          */
  32         public static function iconv( $from, $to, $string ) {
  33                 if ( substr( $to, -8 ) == '//IGNORE' ) {
  34                         $to = substr( $to, 0, strlen( $to ) - 8 );
  35                 }
  36                 if( strcasecmp( $from, $to ) == 0 ) {
  37                         return $string;
  38                 }
  39                 if( strcasecmp( $from, 'utf-8' ) == 0 ) {
  40                         return utf8_decode( $string );
  41                 }
  42                 if( strcasecmp( $to, 'utf-8' ) == 0 ) {
  43                         return utf8_encode( $string );
  44                 }
  45                 return $string;
  46         }
  47
  48         /**
  49          * Fallback implementation for mb_substr, hardcoded to UTF-8.
  50          * Attempts to be at least _moderately_ efficient; best optimized
  51          * for relatively small offset and count values -- about 5x slower
  52          * than native mb_string in my testing.
  53          *
  54          * Larger offsets are still fairly efficient for Latin text, but
  55          * can be up to 100x slower than native if the text is heavily
  56          * multibyte and we have to slog through a few hundred kb.
  57          *
  58          * @param $str
  59          * @param $start
  60          * @param $count string
  61          *
  62          * @return string
  63          */
  64         public static function mb_substr( $str, $start, $count = 'end' ) {
  65                 if( $start != 0 ) {
  66                         $split = self::mb_substr_split_unicode( $str, intval( $start ) );
  67                         $str = substr( $str, $split );
  68                 }
  69
  70                 if( $count !== 'end' ) {
  71                         $split = self::mb_substr_split_unicode( $str, intval( $count ) );
  72                         $str = substr( $str, 0, $split );
  73                 }
  74
  75                 return $str;
  76         }
  77
  78         /**
  79          * @param $str
  80          * @param $splitPos
  81          * @return int
  82          */
  83         public static function mb_substr_split_unicode( $str, $splitPos ) {
  84                 if( $splitPos == 0 ) {
  85                         return 0;
  86                 }
  87
  88                 $byteLen = strlen( $str );
  89
  90                 if( $splitPos > 0 ) {
  91                         if( $splitPos > 256 ) {
  92                                 // Optimize large string offsets by skipping ahead N bytes.
  93                                 // This will cut out most of our slow time on Latin-based text,
  94                                 // and 1/2 to 1/3 on East European and Asian scripts.
  95                                 $bytePos = $splitPos;
  96                                 while ( $bytePos < $byteLen && $str[$bytePos] >= "\x80" && $str[$bytePos] < "\xc0" ) {
  97                                         ++$bytePos;
  98                                 }
  99                                 $charPos = mb_strlen( substr( $str, 0, $bytePos ) );
 100                         } else {
 101                                 $charPos = 0;
 102                                 $bytePos = 0;
 103                         }
 104
 105                         while( $charPos++ < $splitPos ) {
 106                                 ++$bytePos;
 107                                 // Move past any tail bytes
 108                                 while ( $bytePos < $byteLen && $str[$bytePos] >= "\x80" && $str[$bytePos] < "\xc0" ) {
 109                                         ++$bytePos;
 110                                 }
 111                         }
 112                 } else {
 113                         $splitPosX = $splitPos + 1;
 114                         $charPos = 0; // relative to end of string; we don't care about the actual char position here
 115                         $bytePos = $byteLen;
 116                         while( $bytePos > 0 && $charPos-- >= $splitPosX ) {
 117                                 --$bytePos;
 118                                 // Move past any tail bytes
 119                                 while ( $bytePos > 0 && $str[$bytePos] >= "\x80" && $str[$bytePos] < "\xc0" ) {
 120                                         --$bytePos;
 121                                 }
 122                         }
 123                 }
 124
 125                 return $bytePos;
 126         }
 127
 128         /**
 129          * Fallback implementation of mb_strlen, hardcoded to UTF-8.
 130          * @param string $str
 131          * @param string $enc optional encoding; ignored
 132          * @return int
 133          */
 134         public static function mb_strlen( $str, $enc = '' ) {
 135                 $counts = count_chars( $str );
 136                 $total = 0;
 137
 138                 // Count ASCII bytes
 139                 for( $i = 0; $i < 0x80; $i++ ) {
 140                         $total += $counts[$i];
 141                 }
 142
 143                 // Count multibyte sequence heads
 144                 for( $i = 0xc0; $i < 0xff; $i++ ) {
 145                         $total += $counts[$i];
 146                 }
 147                 return $total;
 148         }
 149
 150
 151         /**
 152          * Fallback implementation of mb_strpos, hardcoded to UTF-8.
 153          * @param $haystack String
 154          * @param $needle String
 155          * @param $offset String: optional start position
 156          * @param $encoding String: optional encoding; ignored
 157          * @return int
 158          */
 159         public static function mb_strpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
 160                 $needle = preg_quote( $needle, '/' );
 161
 162                 $ar = array();
 163                 preg_match( '/' . $needle . '/u', $haystack, $ar, PREG_OFFSET_CAPTURE, $offset );
 164
 165                 if( isset( $ar[0][1] ) ) {
 166                         return $ar[0][1];
 167                 } else {
 168                         return false;
 169                 }
 170         }
 171
 172         /**
 173          * Fallback implementation of mb_strrpos, hardcoded to UTF-8.
 174          * @param $haystack String
 175          * @param $needle String
 176          * @param $offset String: optional start position
 177          * @param $encoding String: optional encoding; ignored
 178          * @return int
 179          */
 180         public static function mb_strrpos( $haystack, $needle, $offset = 0, $encoding = '' ) {
 181                 $needle = preg_quote( $needle, '/' );
 182
 183                 $ar = array();
 184                 preg_match_all( '/' . $needle . '/u', $haystack, $ar, PREG_OFFSET_CAPTURE, $offset );
 185
 186                 if( isset( $ar[0] ) && count( $ar[0] ) > 0 &&
 187                         isset( $ar[0][count( $ar[0] ) - 1][1] ) ) {
 188                         return $ar[0][count( $ar[0] ) - 1][1];
 189                 } else {
 190                         return false;
 191                 }
 192         }
 193
 194         /**
 195          * Fallback implementation of stream_resolve_include_path()
 196          * Native stream_resolve_include_path is available for PHP 5 >= 5.3.2
 197          * @param $filename String
 198          * @return String
 199          */
 200         public static function stream_resolve_include_path( $filename ) {
 201                 $pathArray = explode( PATH_SEPARATOR, get_include_path() );
 202                 foreach ( $pathArray as $path ) {
 203                         $fullFilename = $path . DIRECTORY_SEPARATOR . $filename;
 204                         if ( file_exists( $fullFilename ) ) {
 205                                 return $fullFilename;
 206                         }
 207                 }
 208                 return false;
 209         }
 210
 211 }