BibTex.php

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<?php
/* vim: set ts=4 sw=4: */
require_once 'PEAR.php';
class Structures_BibTex {

        var $data;
        var $content;
        var $_delimiters;
        var $warnings;
        var $_options;
        var $rtfstring;
        var $htmlstring;
        var $allowedEntryTypes;
        var $authorstring;


        function Structures_BibTex($options = array()) {
                $this->_delimiters = array(
                        '"' => '"',
                        '{' => '}'
                );
                $this->data = array();
                $this->content = '';
                //$this->_stripDelimiter = $stripDel;
                //$this->_validate       = $val;
                $this->warnings = array();
                $this->_options = array(
                        'stripDelimiter' => true,
                        'validate' => true,
                        'unwrap' => false,
                        'wordWrapWidth' => false,
                        'wordWrapBreak' => "\n",
                        'wordWrapCut' => 0,
                        'removeCurlyBraces' => false,
                        'extractAuthors' => true,
                );
                foreach ($options as $option => $value) {
                        $test = $this->setOption($option, $value);
                        if (PEAR::isError($test)) {
                                //Currently nothing is done here, but it could for example raise an warning
                        }
                }
                $this->rtfstring = 'AUTHORS, "{\b TITLE}", {\i JOURNAL}, YEAR';
                $this->htmlstring = 'AUTHORS, "<strong>TITLE</strong>", <em>JOURNAL</em>, YEAR<br />';
                $this->allowedEntryTypes = array(
                        'article',
                        'book',
                        'booklet',
                        'confernce',
                        'inbook',
                        'incollection',
                        'inproceedings',
                        'manual',
                        'mastersthesis',
                        'misc',
                        'phdthesis',
                        'proceedings',
                        'techreport',
                        'unpublished'
                );
                $this->authorstring = 'VON LAST, JR, FIRST';
        }


        function setOption($option, $value) {
                $ret = true;
                if (array_key_exists($option, $this->_options)) {
                        $this->_options[$option] = $value;
                } else {
                        $ret = PEAR::raiseError('Unknown option ' . $option);
                }

                return $ret;
        }


        function loadFile($filename) {
                if (file_exists($filename)) {
                        if (($this->content = @file_get_contents($filename)) === false) {
                                return PEAR::raiseError('Could not open file ' . $filename);
                        } else {
                                $this->_pos = 0;
                                $this->_oldpos = 0;

                                return true;
                        }
                } else {
                        return PEAR::raiseError('Could not find file ' . $filename);
                }
        }


        function parse() {
                //The amount of opening braces is compared to the amount of closing braces
                //Braces inside comments are ignored
                $this->warnings = array();
                $this->data = array();
                $valid = true;
                $open = 0;
                $entry = false;
                $char = '';
                $lastchar = '';
                $buffer = '';
                for ($i = 0; $i < strlen($this->content); $i ++) {
                        $char = substr($this->content, $i, 1);
                        if ((0 != $open) && ('@' == $char)) {
                                if (! $this->_checkAt($buffer)) {
                                        $this->_generateWarning('WARNING_MISSING_END_BRACE', '', $buffer);
                                        //To correct the data we need to insert a closing brace
                                        $char = '}';
                                        $i --;
                                }
                        }
                        if ((0 == $open) && ('@' == $char)) { //The beginning of an entry
                                $entry = true;
                        } elseif ($entry && ('{' == $char)
                                && ('\\' != $lastchar)
                        ) { //Inside an entry and non quoted brace is opening
                                $open ++;
                        } elseif ($entry && ('}' == $char)
                                && ('\\' != $lastchar)
                        ) { //Inside an entry and non quoted brace is closing
                                $open --;
                                if ($open < 0) { //More are closed than opened
                                        $valid = false;
                                }
                                if (0 == $open) { //End of entry
                                        $entry = false;
                                        $entrydata = $this->_parseEntry($buffer);
                                        if (! $entrydata) {
                                        } else {
                                                $this->data[] = $entrydata;
                                        }
                                        $buffer = '';
                                }
                        }
                        if ($entry) { //Inside entry
                                $buffer .= $char;
                        }
                        $lastchar = $char;
                }
                //If open is one it may be possible that the last ending brace is missing
                if (1 == $open) {
                        $entrydata = $this->_parseEntry($buffer);
                        if (! $entrydata) {
                                $valid = false;
                        } else {
                                $this->data[] = $entrydata;
                                $buffer = '';
                                $open = 0;
                        }
                }
                //At this point the open should be zero
                if (0 != $open) {
                        $valid = false;
                }
                //Are there Multiple entries with the same cite?
                if ($this->_options['validate']) {
                        $cites = array();
                        foreach ($this->data as $entry) {
                                $cites[] = $entry['cite'];
                        }
                        $unique = array_unique($cites);
                        if (sizeof($cites) != sizeof($unique)) { //Some values have not been unique!
                                $notuniques = array();
                                for ($i = 0; $i < sizeof($cites); $i ++) {
                                        if ('' == $unique[$i]) {
                                                $notuniques[] = $cites[$i];
                                        }
                                }
                                $this->_generateWarning('WARNING_MULTIPLE_ENTRIES', implode(',', $notuniques));
                        }
                }
                if ($valid) {
                        $this->content = '';

                        return true;
                } else {
                        return PEAR::raiseError('Unbalanced parenthesis');
                }
        }


        function _parseEntry($entry) {
                $entrycopy = '';
                if ($this->_options['validate']) {
                        $entrycopy = $entry; //We need a copy for printing the warnings
                }
                $ret = array();
                if ('@string' == strtolower(substr($entry, 0, 7))) {
                        //String are not yet supported!
                        if ($this->_options['validate']) {
                                $this->_generateWarning('STRING_ENTRY_NOT_YET_SUPPORTED', '', $entry . '}');
                        }
                } elseif ('@preamble' == strtolower(substr($entry, 0, 9))) {
                        //Preamble not yet supported!
                        if ($this->_options['validate']) {
                                $this->_generateWarning('PREAMBLE_ENTRY_NOT_YET_SUPPORTED', '', $entry . '}');
                        }
                } else {
                        //Parsing all fields
                        while (strrpos($entry, '=') !== false) {
                                $position = strrpos($entry, '=');
                                //Checking that the equal sign is not quoted or is not inside a equation (For example in an abstract)
                                $proceed = true;
                                if (substr($entry, $position - 1, 1) == '\\') {
                                        $proceed = false;
                                }
                                if ($proceed) {
                                        $proceed = $this->_checkEqualSign($entry, $position);
                                }
                                while (! $proceed) {
                                        $substring = substr($entry, 0, $position);
                                        $position = strrpos($substring, '=');
                                        $proceed = true;
                                        if (substr($entry, $position - 1, 1) == '\\') {
                                                $proceed = false;
                                        }
                                        if ($proceed) {
                                                $proceed = $this->_checkEqualSign($entry, $position);
                                        }
                                }
                                $value = trim(substr($entry, $position + 1));
                                $entry = substr($entry, 0, $position);
                                if (',' == substr($value, strlen($value) - 1, 1)) {
                                        $value = substr($value, 0, - 1);
                                }
                                if ($this->_options['validate']) {
                                        $this->_validateValue($value, $entrycopy);
                                }
                                if ($this->_options['stripDelimiter']) {
                                        $value = $this->_stripDelimiter($value);
                                }
                                if ($this->_options['unwrap']) {
                                        $value = $this->_unwrap($value);
                                }
                                if ($this->_options['removeCurlyBraces']) {
                                        $value = $this->_removeCurlyBraces($value);
                                }
                                $position = strrpos($entry, ',');
                                $field = strtolower(trim(substr($entry, $position + 1)));
                                $ret[$field] = $value;
                                $entry = substr($entry, 0, $position);
                        }
                        //Parsing cite and entry type
                        $arr = explode('{', $entry);
                        $ret['cite'] = trim($arr[1]);
                        $ret['entryType'] = strtolower(trim($arr[0]));
                        if ('@' == $ret['entryType']{0}) {
                                $ret['entryType'] = substr($ret['entryType'], 1);
                        }
                        if ($this->_options['validate']) {
                                if (! $this->_checkAllowedEntryType($ret['entryType'])) {
                                        $this->_generateWarning('WARNING_NOT_ALLOWED_ENTRY_TYPE', $ret['entryType'], $entry . '}');
                                }
                        }
                        //Handling the authors
                        if (in_array('author', array_keys($ret)) && $this->_options['extractAuthors']) {
                                $ret['author'] = $this->_extractAuthors($ret['author']);
                        }
                }

                return $ret;
        }


        function _checkEqualSign($entry, $position) {
                $ret = true;
                //This is getting tricky
                //We check the string backwards until the position and count the closing an opening braces
                //If we reach the position the amount of opening and closing braces should be equal
                $length = strlen($entry);
                $open = 0;
                for ($i = $length - 1; $i >= $position; $i --) {
                        $precedingchar = substr($entry, $i - 1, 1);
                        $char = substr($entry, $i, 1);
                        if (('{' == $char) && ('\\' != $precedingchar)) {
                                $open ++;
                        }
                        if (('}' == $char) && ('\\' != $precedingchar)) {
                                $open --;
                        }
                }
                if (0 != $open) {
                        $ret = false;
                }
                //There is still the posibility that the entry is delimited by double quotes.
                //Then it is possible that the braces are equal even if the '=' is in an equation.
                if ($ret) {
                        $entrycopy = trim($entry);
                        $lastchar = $entrycopy{strlen($entrycopy) - 1};
                        if (',' == $lastchar) {
                                $lastchar = $entrycopy{strlen($entrycopy) - 2};
                        }
                        if ('"' == $lastchar) {
                                //The return value is set to false
                                //If we find the closing " before the '=' it is set to true again.
                                //Remember we begin to search the entry backwards so the " has to show up twice - ending and beginning delimiter
                                $ret = false;
                                $found = 0;
                                for ($i = $length; $i >= $position; $i --) {
                                        $precedingchar = substr($entry, $i - 1, 1);
                                        $char = substr($entry, $i, 1);
                                        if (('"' == $char) && ('\\' != $precedingchar)) {
                                                $found ++;
                                        }
                                        if (2 == $found) {
                                                $ret = true;
                                                break;
                                        }
                                }
                        }
                }

                return $ret;
        }


        function _checkAllowedEntryType($entry) {
                return in_array($entry, $this->allowedEntryTypes);
        }


        function _checkAt($entry) {
                $ret = false;
                $opening = array_keys($this->_delimiters);
                $closing = array_values($this->_delimiters);
                //Getting the value (at is only allowd in values)
                if (strrpos($entry, '=') !== false) {
                        $position = strrpos($entry, '=');
                        $proceed = true;
                        if (substr($entry, $position - 1, 1) == '\\') {
                                $proceed = false;
                        }
                        while (! $proceed) {
                                $substring = substr($entry, 0, $position);
                                $position = strrpos($substring, '=');
                                $proceed = true;
                                if (substr($entry, $position - 1, 1) == '\\') {
                                        $proceed = false;
                                }
                        }
                        $value = trim(substr($entry, $position + 1));
                        $open = 0;
                        $char = '';
                        $lastchar = '';
                        for ($i = 0; $i < strlen($value); $i ++) {
                                $char = substr($this->content, $i, 1);
                                if (in_array($char, $opening) && ('\\' != $lastchar)) {
                                        $open ++;
                                } elseif (in_array($char, $closing) && ('\\' != $lastchar)) {
                                        $open --;
                                }
                                $lastchar = $char;
                        }
                        //if open is grater zero were are inside an entry
                        if ($open > 0) {
                                $ret = true;
                        }
                }

                return $ret;
        }


        function _stripDelimiter($entry) {
                $beginningdels = array_keys($this->_delimiters);
                $length = strlen($entry);
                $firstchar = substr($entry, 0, 1);
                $lastchar = substr($entry, - 1, 1);
                while (in_array($firstchar, $beginningdels)) { //The first character is an opening delimiter
                        if ($lastchar == $this->_delimiters[$firstchar]) { //Matches to closing Delimiter
                                $entry = substr($entry, 1, - 1);
                        } else {
                                break;
                        }
                        $firstchar = substr($entry, 0, 1);
                        $lastchar = substr($entry, - 1, 1);
                }

                return $entry;
        }


        function _unwrap($entry) {
                $entry = preg_replace('/\s+/', ' ', $entry);

                return trim($entry);
        }


        function _wordwrap($entry) {
                if (('' != $entry) && (is_string($entry))) {
                        $entry = wordwrap($entry, $this->_options['wordWrapWidth'], $this->_options['wordWrapBreak'], $this->_options['wordWrapCut']);
                }

                return $entry;
        }


        function _extractAuthors($entry) {
                $entry = $this->_unwrap($entry);
                $authorarray = array();
                $authorarray = explode(' and ', $entry);
                for ($i = 0; $i < sizeof($authorarray); $i ++) {
                        $author = trim($authorarray[$i]);
                        /*The first version of how an author could be written (First von Last)
                         has no commas in it*/
                        $first = '';
                        $von = '';
                        $last = '';
                        $jr = '';
                        if (strpos($author, ',') === false) {
                                $tmparray = array();
                                //$tmparray = explode(' ', $author);
                                $tmparray = explode(' |~', $author);
                                $size = sizeof($tmparray);
                                if (1 == $size) { //There is only a last
                                        $last = $tmparray[0];
                                } elseif (2 == $size) { //There is a first and a last
                                        $first = $tmparray[0];
                                        $last = $tmparray[1];
                                } else {
                                        $invon = false;
                                        $inlast = false;
                                        for ($j = 0; $j < ($size - 1); $j ++) {
                                                if ($inlast) {
                                                        $last .= ' ' . $tmparray[$j];
                                                } elseif ($invon) {
                                                        $case = $this->_determineCase($tmparray[$j]);
                                                        if (PEAR::isError($case)) {
                                                                // IGNORE?
                                                        } elseif ((0 == $case) || (- 1 == $case)) { //Change from von to last
                                                                //You only change when there is no more lower case there
                                                                $islast = true;
                                                                for ($k = ($j + 1); $k < ($size - 1); $k ++) {
                                                                        $futurecase = $this->_determineCase($tmparray[$k]);
                                                                        if (PEAR::isError($case)) {
                                                                                // IGNORE?
                                                                        } elseif (0 == $futurecase) {
                                                                                $islast = false;
                                                                        }
                                                                }
                                                                if ($islast) {
                                                                        $inlast = true;
                                                                        if (- 1 == $case) { //Caseless belongs to the last
                                                                                $last .= ' ' . $tmparray[$j];
                                                                        } else {
                                                                                $von .= ' ' . $tmparray[$j];
                                                                        }
                                                                } else {
                                                                        $von .= ' ' . $tmparray[$j];
                                                                }
                                                        } else {
                                                                $von .= ' ' . $tmparray[$j];
                                                        }
                                                } else {
                                                        $case = $this->_determineCase($tmparray[$j]);
                                                        if (PEAR::isError($case)) {
                                                                // IGNORE?
                                                        } elseif (0 == $case) { //Change from first to von
                                                                $invon = true;
                                                                $von .= ' ' . $tmparray[$j];
                                                        } else {
                                                                $first .= ' ' . $tmparray[$j];
                                                        }
                                                }
                                        }
                                        //The last entry is always the last!
                                        $last .= ' ' . $tmparray[$size - 1];
                                }
                        } else { //Version 2 and 3
                                $tmparray = array();
                                $tmparray = explode(',', $author);
                                //The first entry must contain von and last
                                $vonlastarray = array();
                                $vonlastarray = explode(' ', $tmparray[0]);
                                $size = sizeof($vonlastarray);
                                if (1 == $size) { //Only one entry->got to be the last
                                        $last = $vonlastarray[0];
                                } else {
                                        $inlast = false;
                                        for ($j = 0; $j < ($size - 1); $j ++) {
                                                if ($inlast) {
                                                        $last .= ' ' . $vonlastarray[$j];
                                                } else {
                                                        if (0 != ($this->_determineCase($vonlastarray[$j]))) { //Change from von to last
                                                                $islast = true;
                                                                for ($k = ($j + 1); $k < ($size - 1); $k ++) {
                                                                        $this->_determineCase($vonlastarray[$k]);
                                                                        $case = $this->_determineCase($vonlastarray[$k]);
                                                                        if (PEAR::isError($case)) {
                                                                                // IGNORE?
                                                                        } elseif (0 == $case) {
                                                                                $islast = false;
                                                                        }
                                                                }
                                                                if ($islast) {
                                                                        $inlast = true;
                                                                        $last .= ' ' . $vonlastarray[$j];
                                                                } else {
                                                                        $von .= ' ' . $vonlastarray[$j];
                                                                }
                                                        } else {
                                                                $von .= ' ' . $vonlastarray[$j];
                                                        }
                                                }
                                        }
                                        $last .= ' ' . $vonlastarray[$size - 1];
                                }
                                //Now we check if it is version three (three entries in the array (two commas)
                                if (3 == sizeof($tmparray)) {
                                        $jr = $tmparray[1];
                                }
                                //Everything in the last entry is first
                                $first = $tmparray[sizeof($tmparray) - 1];
                        }
                        $authorarray[$i] = array(
                                'first' => trim($first),
                                'von' => trim($von),
                                'last' => trim($last),
                                'jr' => trim($jr)
                        );
                }

                return $authorarray;
        }


        function _determineCase($word) {
                $ret = - 1;
                $trimmedword = trim($word);
                /*We need this variable. Without the next of would not work
                 (trim changes the variable automatically to a string!)*/
                if (is_string($word) && (strlen($trimmedword) > 0)) {
                        $i = 0;
                        $found = false;
                        $openbrace = 0;
                        while (! $found && ($i <= strlen($word))) {
                                $letter = substr($trimmedword, $i, 1);
                                $ord = ord($letter);
                                if ($ord == 123) { //Open brace
                                        $openbrace ++;
                                }
                                if ($ord == 125) { //Closing brace
                                        $openbrace --;
                                }
                                if (($ord >= 65) && ($ord <= 90) && (0 == $openbrace)) { //The first character is uppercase
                                        $ret = 1;
                                        $found = true;
                                } elseif (($ord >= 97) && ($ord <= 122) && (0 == $openbrace)) { //The first character is lowercase
                                        $ret = 0;
                                        $found = true;
                                } else { //Not yet found
                                        $i ++;
                                }
                        }
                } else {
                        $ret = PEAR::raiseError('Could not determine case on word: ' . (string)$word);
                }

                return $ret;
        }


        function _validateValue($entry, $wholeentry) {
                //There is no @ allowed if the entry is enclosed by braces
                if (preg_match('/^{.*@.*}$/', $entry)) {
                        $this->_generateWarning('WARNING_AT_IN_BRACES', $entry, $wholeentry);
                }
                //No escaped " allowed if the entry is enclosed by double quotes
                if (preg_match('/^\".*\\".*\"$/', $entry)) {
                        $this->_generateWarning('WARNING_ESCAPED_DOUBLE_QUOTE_INSIDE_DOUBLE_QUOTES', $entry, $wholeentry);
                }
                //Amount of Braces is not correct
                $open = 0;
                $lastchar = '';
                $char = '';
                for ($i = 0; $i < strlen($entry); $i ++) {
                        $char = substr($entry, $i, 1);
                        if (('{' == $char) && ('\\' != $lastchar)) {
                                $open ++;
                        }
                        if (('}' == $char) && ('\\' != $lastchar)) {
                                $open --;
                        }
                        $lastchar = $char;
                }
                if (0 != $open) {
                        $this->_generateWarning('WARNING_UNBALANCED_AMOUNT_OF_BRACES', $entry, $wholeentry);
                }
        }


        function _removeCurlyBraces($value) {
                //First we save the delimiters
                $beginningdels = array_keys($this->_delimiters);
                $firstchar = substr($entry, 0, 1);
                $lastchar = substr($entry, - 1, 1);
                $begin = '';
                $end = '';
                while (in_array($firstchar, $beginningdels)) { //The first character is an opening delimiter
                        if ($lastchar == $this->_delimiters[$firstchar]) { //Matches to closing Delimiter
                                $begin .= $firstchar;
                                $end .= $lastchar;
                                $value = substr($value, 1, - 1);
                        } else {
                                break;
                        }
                        $firstchar = substr($value, 0, 1);
                        $lastchar = substr($value, - 1, 1);
                }
                //Now we get rid of the curly braces
                $pattern = '/([^\\\\])\{(.*?[^\\\\])\}/';
                $replacement = '$1$2';
                $value = preg_replace($pattern, $replacement, $value);
                //Reattach delimiters
                $value = $begin . $value . $end;

                return $value;
        }


        function _generateWarning($type, $entry, $wholeentry = '') {
                $warning['warning'] = $type;
                $warning['entry'] = $entry;
                $warning['wholeentry'] = $wholeentry;
                $this->warnings[] = $warning;
        }


        function clearWarnings() {
                $this->warnings = array();
        }


        function hasWarning() {
                if (sizeof($this->warnings) > 0) {
                        return true;
                } else {
                        return false;
                }
        }


        function amount() {
                return sizeof($this->data);
        }


        function _formatAuthor($array) {
                if (! array_key_exists('von', $array)) {
                        $array['von'] = '';
                } else {
                        $array['von'] = trim($array['von']);
                }
                if (! array_key_exists('last', $array)) {
                        $array['last'] = '';
                } else {
                        $array['last'] = trim($array['last']);
                }
                if (! array_key_exists('jr', $array)) {
                        $array['jr'] = '';
                } else {
                        $array['jr'] = trim($array['jr']);
                }
                if (! array_key_exists('first', $array)) {
                        $array['first'] = '';
                } else {
                        $array['first'] = trim($array['first']);
                }
                $ret = $this->authorstring;
                $ret = str_replace("VON", $array['von'], $ret);
                $ret = str_replace("LAST", $array['last'], $ret);
                $ret = str_replace("JR", $array['jr'], $ret);
                $ret = str_replace("FIRST", $array['first'], $ret);

                return trim($ret);
        }


        function bibTex() {
                $bibtex = '';
                foreach ($this->data as $entry) {
                        //Intro
                        $bibtex .= '@' . strtolower($entry['entryType']) . ' { ' . $entry['cite'] . ",\n";
                        //Other fields except author
                        foreach ($entry as $key => $val) {
                                if ($this->_options['wordWrapWidth'] > 0) {
                                        $val = $this->_wordWrap($val);
                                }
                                if (! in_array($key, array( 'cite', 'entryType', 'author' ))) {
                                        $bibtex .= "\t" . $key . ' = {' . $val . "},\n";
                                }
                        }
                        //Author
                        if (array_key_exists('author', $entry)) {
                                if ($this->_options['extractAuthors']) {
                                        $tmparray = array(); //In this array the authors are saved and the joind with an and
                                        foreach ($entry['author'] as $authorentry) {
                                                $tmparray[] = $this->_formatAuthor($authorentry);
                                        }
                                        $author = join(' and ', $tmparray);
                                } else {
                                        $author = $entry['author'];
                                }
                        } else {
                                $author = '';
                        }
                        $bibtex .= "\tauthor = {" . $author . "}\n";
                        $bibtex .= "}\n\n";
                }

                return $bibtex;
        }


        function addEntry($newentry) {
                $this->data[] = $newentry;
        }


        function getStatistic() {
                $ret = array();
                foreach ($this->data as $entry) {
                        if (array_key_exists($entry['entryType'], $ret)) {
                                $ret[$entry['entryType']] ++;
                        } else {
                                $ret[$entry['entryType']] = 1;
                        }
                }

                return $ret;
        }


        function rtf() {
                $ret = "{\\rtf\n";
                foreach ($this->data as $entry) {
                        $line = $this->rtfstring;
                        $title = '';
                        $journal = '';
                        $year = '';
                        $authors = '';
                        if (array_key_exists('title', $entry)) {
                                $title = $this->_unwrap($entry['title']);
                        }
                        if (array_key_exists('journal', $entry)) {
                                $journal = $this->_unwrap($entry['journal']);
                        }
                        if (array_key_exists('year', $entry)) {
                                $year = $this->_unwrap($entry['year']);
                        }
                        if (array_key_exists('author', $entry)) {
                                if ($this->_options['extractAuthors']) {
                                        $tmparray = array(); //In this array the authors are saved and the joind with an and
                                        foreach ($entry['author'] as $authorentry) {
                                                $tmparray[] = $this->_formatAuthor($authorentry);
                                        }
                                        $authors = join(', ', $tmparray);
                                } else {
                                        $authors = $entry['author'];
                                }
                        }
                        if (('' != $title) || ('' != $journal) || ('' != $year) || ('' != $authors)) {
                                $line = str_replace("TITLE", $title, $line);
                                $line = str_replace("JOURNAL", $journal, $line);
                                $line = str_replace("YEAR", $year, $line);
                                $line = str_replace("AUTHORS", $authors, $line);
                                $line .= "\n\\par\n";
                                $ret .= $line;
                        } else {
                                $this->_generateWarning('WARNING_LINE_WAS_NOT_CONVERTED', '', print_r($entry, 1));
                        }
                }
                $ret .= '}';

                return $ret;
        }


        function html() {
                $ret = "<p>\n";
                foreach ($this->data as $entry) {
                        $line = $this->htmlstring;
                        $title = '';
                        $journal = '';
                        $year = '';
                        $authors = '';
                        if (array_key_exists('title', $entry)) {
                                $title = $this->_unwrap($entry['title']);
                        }
                        if (array_key_exists('journal', $entry)) {
                                $journal = $this->_unwrap($entry['journal']);
                        }
                        if (array_key_exists('year', $entry)) {
                                $year = $this->_unwrap($entry['year']);
                        }
                        if (array_key_exists('author', $entry)) {
                                if ($this->_options['extractAuthors']) {
                                        $tmparray = array(); //In this array the authors are saved and the joind with an and
                                        foreach ($entry['author'] as $authorentry) {
                                                $tmparray[] = $this->_formatAuthor($authorentry);
                                        }
                                        $authors = join(', ', $tmparray);
                                } else {
                                        $authors = $entry['author'];
                                }
                        }
                        if (('' != $title) || ('' != $journal) || ('' != $year) || ('' != $authors)) {
                                $line = str_replace("TITLE", $title, $line);
                                $line = str_replace("JOURNAL", $journal, $line);
                                $line = str_replace("YEAR", $year, $line);
                                $line = str_replace("AUTHORS", $authors, $line);
                                $line .= "\n";
                                $ret .= $line;
                        } else {
                                $this->_generateWarning('WARNING_LINE_WAS_NOT_CONVERTED', '', print_r($entry, 1));
                        }
                }
                $ret .= "</p>\n";

                return $ret;
        }
}

?>