# learnpress/4.1.6.9.4/inc/class-lp-compress-string.php

LearnPress – WordPress LMS Plugin for Create and Sell Online Courses, version 4.1.6.9.4. 164 lines.

- Page: https://pluginprobe.com/plugins/learnpress/4.1.6.9.4/code/inc/class-lp-compress-string.php
- Raw: https://pluginprobe.com/plugins/learnpress/4.1.6.9.4/raw/inc/class-lp-compress-string.php
- Modified: 2022-08-16T05:12:32+00:00

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```php
<?php
class LP_Compress_String {
	public static function decompressString( $compressed ) {
		$compressed = explode( ',', $compressed );
		$dictSize   = 256;
		$dictionary = array();
		for ( $i = 1; $i < 256; $i ++ ) {
			$dictionary[ $i ] = chr( $i );
		}
		$w      = chr( $compressed[0] );
		$result = $w;
		for ( $i = 1; $i < count( $compressed ); $i ++ ) {
			$entry = '';
			$k     = $compressed[ $i ];
			if ( isset( $dictionary[ $k ] ) ) {
				$entry = $dictionary[ $k ];
			} elseif ( $k == $dictSize ) {
				$entry = $w . self::charAt( $w, 0 );
			} else {
				return null;
			}
			$result                    .= $entry;
			$dictionary[ $dictSize ++ ] = $w . self::charAt( $entry, 0 );
			$w                          = $entry;
		}

		return $result;
	}

	public static function charAt( $string, $index ) {
		if ( $index < mb_strlen( $string ) ) {
			return mb_substr( $string, $index, 1 );
		} else {
			return - 1;
		}
	}

	public static function chr( $u ) {
		return mb_convert_encoding( '&#' . intval( $u ) . ';', 'UTF-8', 'HTML-ENTITIES' );
	}

	public static function toCharCodes( $c ) {
		$x = 'charCodeAt';
		$b = '';
		$e = array();
		$f = str_split( $c );
		$d = [];
		$a = $f[0];
		$g = 256;
		for ( $b = 1; $b < sizeof( $f ); $b ++ ) {
			$c = $f[ $b ];
			if ( null != $e[ $a . $c ] ) {
				$a .= $c;
			} else {
				//$d[]          = 1 < sizeof( $a ) ? $e[ $a ] : $a[ $x ]( 0 );
				$d[]          = 1 < mb_strlen( $a ) ? $e[ $a ] : self::utf8_char_code_at( $a, 0 );
				$e[ $a . $c ] = $g;
				$g ++;
				$a = $c;
			}
		}
		$d[] = 1 < mb_strlen( $a ) ? $e[ $a ] : self::utf8_char_code_at( $a, 0 );

		return $d;
	}

	public static function compressString( $c ) {

		$d = self::toCharCodes( $c );

		for ( $b = 0; $b < sizeof( $d ); $b ++ ) {
			$d[ $b ] = self::chr( $d[ $b ] );
		}

		return join( $d, '' );

		//      $dictSize   = 256;
		//      $dictionary = array();
		//      for ( $i = 0; $i < 256; $i ++ ) {
		//          $dictionary[ chr( $i ) ] = $i;
		//      }
		//      $w      = "";
		//      $result = "";
		//      for ( $i = 0; $i < strlen( $uncompressed ); $i ++ ) {
		//          $c  = self::charAt( $uncompressed, $i );
		//          $wc = $w . $c;
		//          if ( isset( $dictionary[ $wc ] ) ) {
		//              $w = $wc;
		//          } else {
		//              if ( $result != "" ) {
		//                  $result .= "," . $dictionary[ $w ];
		//              } else {
		//                  $result .= $dictionary[ $w ];
		//              }
		//              $dictionary[ $wc ] = $dictSize ++;
		//              $w                 = "" . $c;
		//          }
		//      }
		//      if ( $w != "" ) {
		//          if ( $result != "" ) {
		//              $result .= "," . $dictionary[ $w ];
		//          } else {
		//              $result .= $dictionary[ $w ];
		//
		//          }
		//
		//          return $result;
		//      }
	}

	public static function utf8_char_code_at( $str, $index ) {
		$char      = '';
		$str_index = 0;

		$str = self::utf8_scrub( $str );
		$len = strlen( $str );

		for ( $i = 0; $i < $len; $i += 1 ) {

			$char .= $str[ $i ];

			if ( self::utf8_check_encoding( $char ) ) {

				if ( $str_index === $index ) {
					return self::utf8_ord( $char );
				}

				$char       = '';
				$str_index += 1;
			}
		}

		return null;
	}

	public static function utf8_scrub( $str ) {
		return htmlspecialchars_decode( htmlspecialchars( $str, ENT_SUBSTITUTE, 'UTF-8' ) );
	}

	public static function utf8_check_encoding( $str ) {
		return $str === self::utf8_scrub( $str );
	}

	public static function utf8_ord( $char ) {
		$lead = ord( $char[0] );

		if ( $lead < 0x80 ) {
			return $lead;
		} elseif ( $lead < 0xE0 ) {
			return ( ( $lead & 0x1F ) << 6 )
				   | ( ord( $char[1] ) & 0x3F );
		} elseif ( $lead < 0xF0 ) {
			return ( ( $lead & 0xF ) << 12 )
				   | ( ( ord( $char[1] ) & 0x3F ) << 6 )
				   | ( ord( $char[2] ) & 0x3F );
		} else {
			return ( ( $lead & 0x7 ) << 18 )
				   | ( ( ord( $char[1] ) & 0x3F ) << 12 )
				   | ( ( ord( $char[2] ) & 0x3F ) << 6 )
				   | ( ord( $char[3] ) & 0x3F );
		}
	}
}

```