<?php

namespace WPDT;

/**
 * Our in-house implementation of a parser.
 *
 * A pure PHP parser, DirectLex has absolutely no dependencies, making
 * it a reasonably good default for PHP4.  Written with efficiency in mind,
 * it can be four times faster than HTMLPurifier_Lexer_PEARSax3, although it
 * pales in comparison to HTMLPurifier_Lexer_DOMLex.
 *
 * @todo Reread XML spec and document differences.
 */
class HTMLPurifier_Lexer_DirectLex extends \WPDT\HTMLPurifier_Lexer
{
    /**
     * @type bool
     */
    public $tracksLineNumbers = \true;
    /**
     * Whitespace characters for str(c)spn.
     * @type string
     */
    protected $_whitespace = " \t\r\n";
    /**
     * Callback function for script CDATA fudge
     * @param array $matches, in form of array(opening tag, contents, closing tag)
     * @return string
     */
    protected function scriptCallback($matches)
    {
        return $matches[1] . \htmlspecialchars($matches[2], \ENT_COMPAT, 'UTF-8') . $matches[3];
    }
    /**
     * @param String $html
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return array|HTMLPurifier_Token[]
     */
    public function tokenizeHTML($html, $config, $context)
    {
        // special normalization for script tags without any armor
        // our "armor" heurstic is a < sign any number of whitespaces after
        // the first script tag
        if ($config->get('HTML.Trusted')) {
            $html = \preg_replace_callback('#(<script[^>]*>)(\\s*[^<].+?)(</script>)#si', array($this, 'scriptCallback'), $html);
        }
        $html = $this->normalize($html, $config, $context);
        $cursor = 0;
        // our location in the text
        $inside_tag = \false;
        // whether or not we're parsing the inside of a tag
        $array = array();
        // result array
        // This is also treated to mean maintain *column* numbers too
        $maintain_line_numbers = $config->get('Core.MaintainLineNumbers');
        if ($maintain_line_numbers === null) {
            // automatically determine line numbering by checking
            // if error collection is on
            $maintain_line_numbers = $config->get('Core.CollectErrors');
        }
        if ($maintain_line_numbers) {
            $current_line = 1;
            $current_col = 0;
            $length = \strlen($html);
        } else {
            $current_line = \false;
            $current_col = \false;
            $length = \false;
        }
        $context->register('CurrentLine', $current_line);
        $context->register('CurrentCol', $current_col);
        $nl = "\n";
        // how often to manually recalculate. This will ALWAYS be right,
        // but it's pretty wasteful. Set to 0 to turn off
        $synchronize_interval = $config->get('Core.DirectLexLineNumberSyncInterval');
        $e = \false;
        if ($config->get('Core.CollectErrors')) {
            $e =& $context->get('ErrorCollector');
        }
        // for testing synchronization
        $loops = 0;
        while (++$loops) {
            // $cursor is either at the start of a token, or inside of
            // a tag (i.e. there was a < immediately before it), as indicated
            // by $inside_tag
            if ($maintain_line_numbers) {
                // $rcursor, however, is always at the start of a token.
                $rcursor = $cursor - (int) $inside_tag;
                // Column number is cheap, so we calculate it every round.
                // We're interested at the *end* of the newline string, so
                // we need to add strlen($nl) == 1 to $nl_pos before subtracting it
                // from our "rcursor" position.
                $nl_pos = \strrpos($html, $nl, $rcursor - $length);
                $current_col = $rcursor - (\is_bool($nl_pos) ? 0 : $nl_pos + 1);
                // recalculate lines
                if ($synchronize_interval && $cursor > 0 && $loops % $synchronize_interval === 0) {
                    // time to synchronize!
                    $current_line = 1 + \substr_count($html, $nl, 0, $cursor);
                }
            }
            $position_next_lt = \strpos($html, '<', $cursor);
            $position_next_gt = \strpos($html, '>', $cursor);
            // triggers on "<b>asdf</b>" but not "asdf <b></b>"
            // special case to set up context
            if ($position_next_lt === $cursor) {
                $inside_tag = \true;
                $cursor++;
            }
            if (!$inside_tag && $position_next_lt !== \false) {
                // We are not inside tag and there still is another tag to parse
                $token = new \WPDT\HTMLPurifier_Token_Text($this->parseText(\substr($html, $cursor, $position_next_lt - $cursor), $config));
                if ($maintain_line_numbers) {
                    $token->rawPosition($current_line, $current_col);
                    $current_line += \substr_count($html, $nl, $cursor, $position_next_lt - $cursor);
                }
                $array[] = $token;
                $cursor = $position_next_lt + 1;
                $inside_tag = \true;
                continue;
            } elseif (!$inside_tag) {
                // We are not inside tag but there are no more tags
                // If we're already at the end, break
                if ($cursor === \strlen($html)) {
                    break;
                }
                // Create Text of rest of string
                $token = new \WPDT\HTMLPurifier_Token_Text($this->parseText(\substr($html, $cursor), $config));
                if ($maintain_line_numbers) {
                    $token->rawPosition($current_line, $current_col);
                }
                $array[] = $token;
                break;
            } elseif ($inside_tag && $position_next_gt !== \false) {
                // We are in tag and it is well formed
                // Grab the internals of the tag
                $strlen_segment = $position_next_gt - $cursor;
                if ($strlen_segment < 1) {
                    // there's nothing to process!
                    $token = new \WPDT\HTMLPurifier_Token_Text('<');
                    $cursor++;
                    continue;
                }
                $segment = \substr($html, $cursor, $strlen_segment);
                if ($segment === \false) {
                    // somehow, we attempted to access beyond the end of
                    // the string, defense-in-depth, reported by Nate Abele
                    break;
                }
                // Check if it's a comment
                if (\substr($segment, 0, 3) === '!--') {
                    // re-determine segment length, looking for -->
                    $position_comment_end = \strpos($html, '-->', $cursor);
                    if ($position_comment_end === \false) {
                        // uh oh, we have a comment that extends to
                        // infinity. Can't be helped: set comment
                        // end position to end of string
                        if ($e) {
                            $e->send(\E_WARNING, 'Lexer: Unclosed comment');
                        }
                        $position_comment_end = \strlen($html);
                        $end = \true;
                    } else {
                        $end = \false;
                    }
                    $strlen_segment = $position_comment_end - $cursor;
                    $segment = \substr($html, $cursor, $strlen_segment);
                    $token = new \WPDT\HTMLPurifier_Token_Comment(\substr($segment, 3, $strlen_segment - 3));
                    if ($maintain_line_numbers) {
                        $token->rawPosition($current_line, $current_col);
                        $current_line += \substr_count($html, $nl, $cursor, $strlen_segment);
                    }
                    $array[] = $token;
                    $cursor = $end ? $position_comment_end : $position_comment_end + 3;
                    $inside_tag = \false;
                    continue;
                }
                // Check if it's an end tag
                $is_end_tag = \strpos($segment, '/') === 0;
                if ($is_end_tag) {
                    $type = \substr($segment, 1);
                    $token = new \WPDT\HTMLPurifier_Token_End($type);
                    if ($maintain_line_numbers) {
                        $token->rawPosition($current_line, $current_col);
                        $current_line += \substr_count($html, $nl, $cursor, $position_next_gt - $cursor);
                    }
                    $array[] = $token;
                    $inside_tag = \false;
                    $cursor = $position_next_gt + 1;
                    continue;
                }
                // Check leading character is alnum, if not, we may
                // have accidently grabbed an emoticon. Translate into
                // text and go our merry way
                if (!\ctype_alpha($segment[0])) {
                    // XML:  $segment[0] !== '_' && $segment[0] !== ':'
                    if ($e) {
                        $e->send(\E_NOTICE, 'Lexer: Unescaped lt');
                    }
                    $token = new \WPDT\HTMLPurifier_Token_Text('<');
                    if ($maintain_line_numbers) {
                        $token->rawPosition($current_line, $current_col);
                        $current_line += \substr_count($html, $nl, $cursor, $position_next_gt - $cursor);
                    }
                    $array[] = $token;
                    $inside_tag = \false;
                    continue;
                }
                // Check if it is explicitly self closing, if so, remove
                // trailing slash. Remember, we could have a tag like <br>, so
                // any later token processing scripts must convert improperly
                // classified EmptyTags from StartTags.
                $is_self_closing = \strrpos($segment, '/') === $strlen_segment - 1;
                if ($is_self_closing) {
                    $strlen_segment--;
                    $segment = \substr($segment, 0, $strlen_segment);
                }
                // Check if there are any attributes
                $position_first_space = \strcspn($segment, $this->_whitespace);
                if ($position_first_space >= $strlen_segment) {
                    if ($is_self_closing) {
                        $token = new \WPDT\HTMLPurifier_Token_Empty($segment);
                    } else {
                        $token = new \WPDT\HTMLPurifier_Token_Start($segment);
                    }
                    if ($maintain_line_numbers) {
                        $token->rawPosition($current_line, $current_col);
                        $current_line += \substr_count($html, $nl, $cursor, $position_next_gt - $cursor);
                    }
                    $array[] = $token;
                    $inside_tag = \false;
                    $cursor = $position_next_gt + 1;
                    continue;
                }
                // Grab out all the data
                $type = \substr($segment, 0, $position_first_space);
                $attribute_string = \trim(\substr($segment, $position_first_space));
                if ($attribute_string) {
                    $attr = $this->parseAttributeString($attribute_string, $config, $context);
                } else {
                    $attr = array();
                }
                if ($is_self_closing) {
                    $token = new \WPDT\HTMLPurifier_Token_Empty($type, $attr);
                } else {
                    $token = new \WPDT\HTMLPurifier_Token_Start($type, $attr);
                }
                if ($maintain_line_numbers) {
                    $token->rawPosition($current_line, $current_col);
                    $current_line += \substr_count($html, $nl, $cursor, $position_next_gt - $cursor);
                }
                $array[] = $token;
                $cursor = $position_next_gt + 1;
                $inside_tag = \false;
                continue;
            } else {
                // inside tag, but there's no ending > sign
                if ($e) {
                    $e->send(\E_WARNING, 'Lexer: Missing gt');
                }
                $token = new \WPDT\HTMLPurifier_Token_Text('<' . $this->parseText(\substr($html, $cursor), $config));
                if ($maintain_line_numbers) {
                    $token->rawPosition($current_line, $current_col);
                }
                // no cursor scroll? Hmm...
                $array[] = $token;
                break;
            }
            break;
        }
        $context->destroy('CurrentLine');
        $context->destroy('CurrentCol');
        return $array;
    }
    /**
     * Takes the inside of an HTML tag and makes an assoc array of attributes.
     *
     * @param string $string Inside of tag excluding name.
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return array Assoc array of attributes.
     */
    public function parseAttributeString($string, $config, $context)
    {
        $string = (string) $string;
        // quick typecast
        if ($string == '') {
            return array();
        }
        // no attributes
        $e = \false;
        if ($config->get('Core.CollectErrors')) {
            $e =& $context->get('ErrorCollector');
        }
        // let's see if we can abort as quickly as possible
        // one equal sign, no spaces => one attribute
        $num_equal = \substr_count($string, '=');
        $has_space = \strpos($string, ' ');
        if ($num_equal === 0 && !$has_space) {
            // bool attribute
            return array($string => $string);
        } elseif ($num_equal === 1 && !$has_space) {
            // only one attribute
            list($key, $quoted_value) = \explode('=', $string);
            $quoted_value = \trim($quoted_value);
            if (!$key) {
                if ($e) {
                    $e->send(\E_ERROR, 'Lexer: Missing attribute key');
                }
                return array();
            }
            if (!$quoted_value) {
                return array($key => '');
            }
            $first_char = @$quoted_value[0];
            $last_char = @$quoted_value[\strlen($quoted_value) - 1];
            $same_quote = $first_char == $last_char;
            $open_quote = $first_char == '"' || $first_char == "'";
            if ($same_quote && $open_quote) {
                // well behaved
                $value = \substr($quoted_value, 1, \strlen($quoted_value) - 2);
            } else {
                // not well behaved
                if ($open_quote) {
                    if ($e) {
                        $e->send(\E_ERROR, 'Lexer: Missing end quote');
                    }
                    $value = \substr($quoted_value, 1);
                } else {
                    $value = $quoted_value;
                }
            }
            if ($value === \false) {
                $value = '';
            }
            return array($key => $this->parseAttr($value, $config));
        }
        // setup loop environment
        $array = array();
        // return assoc array of attributes
        $cursor = 0;
        // current position in string (moves forward)
        $size = \strlen($string);
        // size of the string (stays the same)
        // if we have unquoted attributes, the parser expects a terminating
        // space, so let's guarantee that there's always a terminating space.
        $string .= ' ';
        $old_cursor = -1;
        while ($cursor < $size) {
            if ($old_cursor >= $cursor) {
                throw new \Exception("Infinite loop detected");
            }
            $old_cursor = $cursor;
            $cursor += $value = \strspn($string, $this->_whitespace, $cursor);
            // grab the key
            $key_begin = $cursor;
            //we're currently at the start of the key
            // scroll past all characters that are the key (not whitespace or =)
            $cursor += \strcspn($string, $this->_whitespace . '=', $cursor);
            $key_end = $cursor;
            // now at the end of the key
            $key = \substr($string, $key_begin, $key_end - $key_begin);
            if (!$key) {
                if ($e) {
                    $e->send(\E_ERROR, 'Lexer: Missing attribute key');
                }
                $cursor += 1 + \strcspn($string, $this->_whitespace, $cursor + 1);
                // prevent infinite loop
                continue;
                // empty key
            }
            // scroll past all whitespace
            $cursor += \strspn($string, $this->_whitespace, $cursor);
            if ($cursor >= $size) {
                $array[$key] = $key;
                break;
            }
            // if the next character is an equal sign, we've got a regular
            // pair, otherwise, it's a bool attribute
            $first_char = @$string[$cursor];
            if ($first_char == '=') {
                // key="value"
                $cursor++;
                $cursor += \strspn($string, $this->_whitespace, $cursor);
                if ($cursor === \false) {
                    $array[$key] = '';
                    break;
                }
                // we might be in front of a quote right now
                $char = @$string[$cursor];
                if ($char == '"' || $char == "'") {
                    // it's quoted, end bound is $char
                    $cursor++;
                    $value_begin = $cursor;
                    $cursor = \strpos($string, $char, $cursor);
                    $value_end = $cursor;
                } else {
                    // it's not quoted, end bound is whitespace
                    $value_begin = $cursor;
                    $cursor += \strcspn($string, $this->_whitespace, $cursor);
                    $value_end = $cursor;
                }
                // we reached a premature end
                if ($cursor === \false) {
                    $cursor = $size;
                    $value_end = $cursor;
                }
                $value = \substr($string, $value_begin, $value_end - $value_begin);
                if ($value === \false) {
                    $value = '';
                }
                $array[$key] = $this->parseAttr($value, $config);
                $cursor++;
            } else {
                // boolattr
                if ($key !== '') {
                    $array[$key] = $key;
                } else {
                    // purely theoretical
                    if ($e) {
                        $e->send(\E_ERROR, 'Lexer: Missing attribute key');
                    }
                }
            }
        }
        return $array;
    }
}
// vim: et sw=4 sts=4
