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f99fcffeb9
of search_lexer now accepts the parser argument by reference all... one time it's called :)
305 lines
9.5 KiB
PHP
305 lines
9.5 KiB
PHP
<?php // $Id$
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require_once($CFG->libdir.'/lexer.php');
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// Constants for the various types of tokens
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define("TOKEN_USER","0");
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define("TOKEN_META","1");
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define("TOKEN_EXACT","2");
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define("TOKEN_NEGATE","3");
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define("TOKEN_STRING","4");
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define("TOKEN_USERID","5");
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// Class to hold token/value pairs after they're parsed.
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class search_token {
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var $value;
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var $type;
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function search_token($type,$value){
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$this->type = $type;
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$this->value = $this->sanitize($value);
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}
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// Try to clean up user input to avoid potential security issues.
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// Need to think about this some more.
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function sanitize($userstring){
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return htmlentities(addslashes($userstring));
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}
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function getValue(){
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return $this->value;
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}
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function getType(){
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return $this->type;
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}
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}
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// This class does the heavy lifting of lexing the search string into tokens.
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// Using a full-blown lexer is probably overkill for this application, but
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// might be useful for other tasks.
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class search_lexer extends Lexer{
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function search_lexer(&$parser){
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// Call parent constructor.
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$this->Lexer($parser);
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//Set up the state machine and pattern matches for transitions.
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// Patterns to handle strings of the form userid:foo
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// If we see the string user: while in the base accept state, start
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// parsing a username and go to the inuserid state.
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$this->addEntryPattern("userid:\S+","accept","inuserid");
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// Snarf everything into the username until we see whitespace, then exit
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// back to the base accept state.
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$this->addExitPattern("\s","inuserid");
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// Patterns to handle strings of the form user:foo
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// If we see the string user: while in the base accept state, start
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// parsing a username and go to the inusername state.
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$this->addEntryPattern("user:\S+","accept","inusername");
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// Snarf everything into the username until we see whitespace, then exit
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// back to the base accept state.
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$this->addExitPattern("\s","inusername");
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// Patterns to handle strings of the form meta:foo
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// If we see the string meta: while in the base accept state, start
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// parsing a username and go to the inmeta state.
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$this->addEntryPattern("subject:\S+","accept","inmeta");
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// Snarf everything into the meta token until we see whitespace, then exit
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// back to the base accept state.
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$this->addExitPattern("\s","inmeta");
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// Patterns to handle required exact match strings (+foo) .
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// If we see a + sign while in the base accept state, start
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// parsing an exact match string and enter the inrequired state
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$this->addEntryPattern("\+\S+","accept","inrequired");
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// When we see white space, exit back to accept state.
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$this->addExitPattern("\s","inrequired");
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// Handle excluded strings (-foo)
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// If we see a - sign while in the base accept state, start
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// parsing an excluded string and enter the inexcluded state
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$this->addEntryPattern("\-\S+","accept","inexcluded");
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// When we see white space, exit back to accept state.
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$this->addExitPattern("\s","inexcluded");
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// Patterns to handle quoted strings.
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// If we see a quote while in the base accept state, start
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// parsing a quoted string and enter the inquotedstring state.
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// Grab everything until we see the closing quote.
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$this->addEntryPattern("\"[^\"]+","accept","inquotedstring");
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// When we see a closing quote, reenter the base accept state.
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$this->addExitPattern("\"","inquotedstring");
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// Patterns to handle ordinary, nonquoted words.
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// When we see non-whitespace, snarf everything into the nonquoted word
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// until we see whitespace again.
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$this->addEntryPattern("\S+","accept","plainstring");
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// Once we see whitespace, reenter the base accept state.
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$this->addExitPattern("\s","plainstring");
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}
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}
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// This class takes care of sticking the proper token type/value pairs into
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// the parsed token array.
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// Most functions in this class should only be called by the lexer, the
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// one exception being getParseArray() which returns the result.
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class search_parser {
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var $tokens;
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// This function is called by the code that's interested in the result of the parse operation.
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function get_parsed_array(){
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return $this->tokens;
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}
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/*
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* Functions below this are part of the state machine for the parse
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* operation and should not be called directly.
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*/
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// Base state. No output emitted.
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function accept() {
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return true;
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}
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// State for handling userid:foo constructs. Potentially emits a token.
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function inuserid($content){
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if (strlen($content) < 8) { // State exit or missing parameter.
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return true;
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}
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// Strip off the userid: part and add the reminder to the parsed token array
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$param = trim(substr($content,7));
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$this->tokens[] = new search_token(TOKEN_USERID,$param);
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return true;
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}
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// State for handling user:foo constructs. Potentially emits a token.
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function inusername($content){
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if (strlen($content) < 6) { // State exit or missing parameter.
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return true;
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}
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// Strip off the user: part and add the reminder to the parsed token array
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$param = trim(substr($content,5));
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$this->tokens[] = new search_token(TOKEN_USER,$param);
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return true;
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}
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// State for handling meta:foo constructs. Potentially emits a token.
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function inmeta($content){
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if (strlen($content) < 9) { // Missing parameter.
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return true;
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}
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// Strip off the meta: part and add the reminder to the parsed token array.
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$param = trim(substr($content,8));
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$this->tokens[] = new search_token(TOKEN_META,$param);
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return true;
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}
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// State entered when we've seen a required string (+foo). Potentially
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// emits a token.
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function inrequired($content){
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if (strlen($content) < 2) { // State exit or missing parameter, don't emit.
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return true;
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}
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// Strip off the + sign and add the reminder to the parsed token array.
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$this->tokens[] = new search_token(TOKEN_EXACT,substr($content,1));
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return true;
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}
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// State entered when we've seen an excluded string (-foo). Potentially
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// emits a token.
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function inexcluded($content){
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if (strlen($content) < 2) { // State exit or missing parameter.
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return true;
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}
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// Strip off the -sign and add the reminder to the parsed token array.
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$this->tokens[] = new search_token(TOKEN_NEGATE,substr($content,1));
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return true;
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}
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// State entered when we've seen a quoted string. Potentially emits a token.
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function inquotedstring($content){
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if (strlen($content) < 2) { // State exit or missing parameter.
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return true;
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}
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// Strip off the opening quote and add the reminder to the parsed token array.
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$this->tokens[] = new search_token(TOKEN_STRING,substr($content,1));
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return true;
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}
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// State entered when we've seen an ordinary, non-quoted word. Potentially
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// emits a token.
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function plainstring($content){
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if (ctype_space($content)) { // State exit
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return true;
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}
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// Add the string to the parsed token array.
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$this->tokens[] = new search_token(TOKEN_STRING,$content);
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return true;
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}
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}
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// Primitive function to generate a SQL string from a parse tree.
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// Parameters:
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//
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// $parsetree should be a parse tree generated by a
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// search_lexer/search_parser combination.
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// Other fields are database table names to search.
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function search_generate_SQL($parsetree, $datafield, $metafield, $mainidfield, $useridfield,
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$userfirstnamefield, $userlastnamefield) {
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global $CFG;
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if ($CFG->dbtype == "postgres7") {
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$LIKE = "ILIKE"; // case-insensitive
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$NOTLIKE = "NOT ILIKE"; // case-insensitive
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$REGEXP = "~*";
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$NOTREGEXP = "!~*";
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} else {
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$LIKE = "LIKE";
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$NOTLIKE = "NOT LIKE";
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$REGEXP = "REGEXP";
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$NOTREGEXP = "NOT REGEXP";
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}
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$ntokens = count($parsetree);
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if ($ntokens == 0) {
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return "";
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}
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$SQLString = '';
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for ($i=0; $i<$ntokens; $i++){
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if ($i > 0) {// We have more than one clause, need to tack on AND
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$SQLString .= ' AND ';
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}
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$type = $parsetree[$i]->getType();
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$value = $parsetree[$i]->getValue();
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switch($type){
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case TOKEN_STRING:
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$SQLString .= "(($datafield $LIKE '%$value%') OR ($metafield $LIKE '%$value%') )";
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break;
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case TOKEN_EXACT:
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$SQLString .= "(($datafield $REGEXP '[[:<:]]".$value."[[:>:]]') OR ($metafield $REGEXP '[[:<:]]".$value."[[:>:]]'))";
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break;
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case TOKEN_META:
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if ($metafield != '') {
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$SQLString .= "($metafield $LIKE '%$value%')";
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}
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break;
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case TOKEN_USER:
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$SQLString .= "(($mainidfield = $useridfield) AND (($userfirstnamefield $LIKE '%$value%') OR ($userlastnamefield $LIKE '%$value%')))";
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break;
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case TOKEN_USERID:
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$SQLString .= "($useridfield = $value)";
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break;
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case TOKEN_NEGATE:
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$SQLString .= "(NOT (($datafield $LIKE '%$value%') OR ($metafield $LIKE '%$value%')))";
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break;
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default:
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return '';
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}
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}
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return $SQLString;
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}
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?>
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