Common: helpers/EscapeParser.php5 Source File

00001 <?php
00002 
00003 // TODO: make this not static
00012 abstract class EscapeParser {
00013     private static $source;
00014 
00015     const EOT = 0;
00016     const GT = 1;
00017     const LT = 2;
00018     const AMP = 3;
00019     const CB_START = 4;
00020     const CB_END = 5;
00021     const LIT_START = 6;
00022     const LIT_END = 7;
00023     const ENT_START = 9;
00024     const ENT_END = 10;
00025     const CMD = 11;
00026     const ID = 12;
00027     const ARG_START = 13;
00028     const ARG_END = 14;
00029     const EQUAL = 15;
00030     const COMMA = 16;
00031     const BLOCK_START = 17;
00032     const BLOCK_END = 5;    // same as CB_END
00033     const NORMAL = 18;
00034     const ENTITY = 19;
00035     const UNESC_ENTITY = 40;
00036 
00037     private static $pos = 0;
00038     private static $tokenType = self::EOT;
00039     private static $token = '';
00040     private static $curLine = 0;
00041     private static $lineOffset = 0;
00042     private static $lastToken = '';
00043     private static $blockStart = 0;
00044 
00045     private static $errors = array();
00046 
00056     public static function parseString($str, $preAppendErr = '') {
00057         self::$source = $str;
00058         self::$pos = 0;
00059         self::$tokenType = self::EOT;
00060         self::$token = '';
00061         self::$curLine = 1;
00062         self::$lineOffset = 0;
00063         self::$lastToken = '';
00064         self::$blockStart = 0;
00065         self::$errors = array();
00066 
00067         // short-circuit evaluation: only calls self::top() if self::advance() succeeds; if either fails, the errors
00068         //   are returned; note also that $ret is assigned in the if-statement and that is what is returned in the
00069         //   else-clause
00070         if(!self::advance() || ($ret = self::top()) === false) {
00071             $newErrors = array();
00072             foreach(self::$errors as $err)
00073                 $newErrors[] = $preAppendErr . $err;
00074             return $newErrors;
00075         }
00076         else
00077             return $ret;
00078     }
00079 
00087     private static function advance() {
00088         self::$lastToken = self::$token;
00089         if(self::$pos >= strlen(self::$source)) {
00090             self::$tokenType = self::EOT;
00091             self::$token = '';
00092             self::$pos++;
00093             return true;
00094         }
00095 
00096         if(self::$source{self::$pos} == '&') {
00097             self::$tokenType = self::UNESC_ENTITY;
00098             self::$token = '&';
00099             self::$pos++;
00100             return true;
00101         }
00102         else if(self::$source{self::$pos} == '[') {
00103             self::$tokenType = self::ARG_START;
00104             self::$token = '[';
00105             self::$pos++;
00106             return true;
00107         }
00108         else if(self::$source{self::$pos} == ']') {
00109             self::$tokenType = self::ARG_END;
00110             self::$token = ']';
00111             self::$pos++;
00112             return true;
00113         }
00114         else if(self::$source{self::$pos} == '{') {
00115             self::$tokenType = self::CB_START;
00116             self::$token = '{';
00117             self::$pos++;
00118             return true;
00119         }
00120         else if(self::$source{self::$pos} == ')') {
00121             self::$tokenType = self::ENT_END;
00122             self::$token = ')';
00123             self::$pos++;
00124             return true;
00125         }
00126         else if(self::$source{self::$pos} == ',') {
00127             self::$tokenType = self::COMMA;
00128             self::$token = ',';
00129             self::$pos++;
00130             return true;
00131         }
00132         else if(self::$source{self::$pos} == '=') {
00133             self::$tokenType = self::EQUAL;
00134             self::$token = '=';
00135             self::$pos++;
00136             return true;
00137         }
00138         else if(self::$source{self::$pos} != '\\') {
00139             self::$tokenType = self::ENTITY;
00140             self::$token = '';
00141             while(self::$pos < strlen(self::$source) &&
00142                     (self::$source{self::$pos} != '\\' && self::$source{self::$pos} != ')'
00143                     && self::$source{self::$pos} != ']' && self::$source{self::$pos} != ','
00144                     && self::$source{self::$pos} != '=' && self::$source{self::$pos} != '&')) {
00145                 if(self::$tokenType == self::ENTITY && (!ctype_alnum(self::$source{self::$pos})
00146                     && self::$source{self::$pos} != '_' && self::$source{self::$pos} != '#'
00147                     && self::$source{self::$pos} != '$'))
00148                     self::$tokenType = self::NORMAL;
00149                 if(self::$source{self::$pos} == "\n" || self::$source{self::$pos} == "\r") {
00150                     self::$lineOffset = self::$pos + 1;
00151                     self::$curLine++;
00152                 }
00153                 self::$token .= self::$source{self::$pos};
00154                 self::$pos++;
00155             }
00156             return true;
00157         }
00158 
00159         self::$pos++;
00160         if(self::$pos >= strlen(self::$source)) {
00161             self::$errors[] = 'Unexpected end of text on line ' . self::$curLine;
00162             return false;
00163         }
00164         if(self::$source{self::$pos} == "\n" || self::$source{self::$pos} == "\r") {
00165             self::$curLine++;
00166             self::$lineOffset = self::$pos + 1;
00167         }
00168 
00169         $chr = self::$source{self::$pos};
00170         self::$token = "\\$chr";
00171         switch($chr) {
00172             case '<':
00173                 self::$tokenType = self::LT;
00174                 break;
00175             case '>';
00176                 self::$tokenType = self::GT;
00177                 break;
00178             case '&';
00179                 self::$tokenType = self::AMP;
00180                 break;
00181             case '{':
00182                 self::$tokenType = self::CB_START;
00183                 break;
00184             case '}':
00185                 self::$tokenType = self::CB_END;
00186                 break;
00187             case '[':
00188                 self::$tokenType = self::LIT_START;
00189                 break;
00190             case ']':
00191                 self::$tokenType = self::LIT_END;
00192                 break;
00193             case '(':
00194                 self::$tokenType = self::ENT_START;
00195                 break;
00196             case ':':
00197                 self::$tokenType = self::CMD;
00198                 break;
00199             default:
00200                 if($chr == "\n" || $chr == "\r") {
00201                     self::$curLine++;
00202                     self::$lineOffset = self::$pos + 1;
00203                 }
00204                 self::$token = $chr;
00205                 self::$tokenType = self::NORMAL;
00206                 break;
00207         }
00208         self::$pos++;
00209 
00210         return true;
00211     }
00212 
00220     private static function top() {
00221         $collect = '';
00222         while(self::$tokenType != self::EOT) {
00223             switch(self::$tokenType) {
00224                 case self::UNESC_ENTITY:
00225                     self::$errors[] = "On line " . self::$curLine . " [column " . (self::$pos - self::$lineOffset)
00226                         . "]: Regular XML entities not supported!";
00227                     return false;
00228                     break;
00229                 case self::GT:
00230                     $collect .= '&amp;gt;';
00231                     if(!self::advance()) return false;
00232                     break;
00233                 case self::LT:
00234                     $collect .= '&amp;lt;';
00235                     if(!self::advance()) return false;
00236                     break;
00237                 case self::AMP:
00238                     $collect .= '&amp;amp;';
00239                     if(!self::advance()) return false;
00240                     break;
00241                 case self::ENT_START:
00242                     if(!self::advance()) return false;
00243                     $ret = self::parseEntity();
00244                     if($ret === false) return false;
00245                     $collect .= $ret;
00246                     break;
00247                 case self::LIT_START:
00248                     if(!self::advance()) return false;
00249                     $ret = self::parseLiteral();
00250                     if($ret === false) return false;
00251                     $collect .= $ret;
00252                     break;
00253                 case self::CB_START:
00254                     if(!self::advance()) return false;
00255                     $ret = self::parseCodeBlock();
00256                     if($ret === false) return false;
00257                     $collect .= $ret;
00258                     break;
00259                 case self::CMD:
00260                     if(!self::advanced()) return false;
00261                     $ret = self::parseCommand();
00262                     if($ret === false) return false;
00263                     $collect .= $ret;
00264                     break;
00265                 default:
00266                     $collect .= self::$token;
00267                     if(!self::advance()) return false;
00268                     break;
00269             }
00270         }
00271 
00272         return $collect;
00273     }
00274 
00282     private static function parseEntity() {
00283         if(self::$tokenType != self::ENTITY) {
00284             self::$errors[] = "On line " . self::$curLine . " [column " . (self::$pos - self::$lineOffset)
00285                     . "]: Entity expected after '<tt>\\(</tt>' (invalid: '" . htmlspecialchars(self::$token) . "')";
00286             return false;
00287         }
00288         $entity = self::$token;
00289         if(!self::advance()) return false;
00290         if(self::$tokenType != self::ENT_END) {
00291             self::$errors[] = "On line " . self::$curLine . " [column " . (self::$pos - self::$lineOffset)
00292                     . "]: Right parenthesis expected after entity ('<tt>\\(" . htmlspecialchars(self::$lastToken) . "</tt>')";
00293             return false;
00294         }
00295         if(!self::advance()) return false;
00296         return '&amp;' . $entity . ';';
00297     }
00298 
00306     private static function parseLiteral() {
00307         $collect = '';
00308         self::$blockStart = self::$curLine;
00309         while(self::$tokenType != self::LIT_END) {
00310             if(self::$tokenType == self::EOT) {
00311                 self::$errors[] = 'Unclosed literal string started on line ' . self::$blockStart . " [column "
00312                         . (self::$pos - self::$lineOffset) . "] (missing '<tt>\\]</tt>')";
00313                 return false;
00314             }
00315             $collect .= self::$token;
00316             if(!self::advance()) return false;
00317         }
00318         if(!self::advance()) return false;
00319         return '<span><![CDATA[' . base64_encode(htmlspecialchars($collect)) . ']]></span>';
00320     }
00321 
00329     private static function parseCodeBlock() {
00330         $collect = '';
00331         self::$blockStart = self::$curLine;
00332         while(self::$tokenType != self::CB_END) {
00333             if(self::$tokenType == self::EOT) {
00334                 self::$errors[] = 'Unclosed code block started on line ' . self::$blockStart . " [column "
00335                     . (self::$pos - self::$lineOffset) . "] (missing '<tt>\\}</tt>')";
00336                 return false;
00337             }
00338             $collect .= self::$token;
00339             if(!self::advance()) return false;
00340         }
00341         if(!self::advance()) return false;
00342         return '<p><pre><![CDATA[' . base64_encode(htmlspecialchars($collect)) . ']]></pre></p>';
00343     }
00344 
00352     private static function parseCommand() {
00353         self::$errors[] = 'Commands not supported yet!';
00354         return false;
00355     }
00356 }
00357 
00358 ?>