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<?php
/** @file
* The scanner.
*/
namespace QueryPath\CSS;
/**
* Scanner for CSS selector parsing.
*
* This provides a simple scanner for traversing an input stream.
*
* @ingroup querypath_css
*/
final class Scanner {
var $is = NULL;
public $value = NULL;
public $token = NULL;
var $recurse = FALSE;
var $it = 0;
/**
* Given a new input stream, tokenize the CSS selector string.
* @see InputStream
* @param InputStream $in
* An input stream to be scanned.
*/
public function __construct(InputStream $in) {
$this->is = $in;
}
/**
* Return the position of the reader in the string.
*/
public function position() {
return $this->is->position;
}
/**
* See the next char without removing it from the stack.
*
* @return char
* Returns the next character on the stack.
*/
public function peek() {
return $this->is->peek();
}
/**
* Get the next token in the input stream.
*
* This sets the current token to the value of the next token in
* the stream.
*
* @return int
* Returns an int value corresponding to one of the Token constants,
* or FALSE if the end of the string is reached. (Remember to use
* strong equality checking on FALSE, since 0 is a valid token id.)
*/
public function nextToken() {
$tok = -1;
++$this->it;
if ($this->is->isEmpty()) {
if ($this->recurse) {
throw new \QueryPath\Exception("Recursion error detected at iteration " . $this->it . '.');
exit();
}
//print "{$this->it}: All done\n";
$this->recurse = TRUE;
$this->token = FALSE;
return FALSE;
}
$ch = $this->is->consume();
//print __FUNCTION__ . " Testing $ch.\n";
if (ctype_space($ch)) {
$this->value = ' '; // Collapse all WS to a space.
$this->token = $tok = Token::white;
//$ch = $this->is->consume();
return $tok;
}
if (ctype_alnum($ch) || $ch == '-' || $ch == '_') {
// It's a character
$this->value = $ch; //strtolower($ch);
$this->token = $tok = Token::char;
return $tok;
}
$this->value = $ch;
switch($ch) {
case '*':
$tok = Token::star;
break;
case chr(ord('>')):
$tok = Token::rangle;
break;
case '.':
$tok = Token::dot;
break;
case '#':
$tok = Token::octo;
break;
case '[':
$tok = Token::lsquare;
break;
case ']':
$tok = Token::rsquare;
break;
case ':':
$tok = Token::colon;
break;
case '(':
$tok = Token::lparen;
break;
case ')':
$tok = Token::rparen;
break;
case '+':
$tok = Token::plus;
break;
case '~':
$tok = Token::tilde;
break;
case '=':
$tok = Token::eq;
break;
case '|':
$tok = Token::pipe;
break;
case ',':
$tok = Token::comma;
break;
case chr(34):
$tok = Token::quote;
break;
case "'":
$tok = Token::squote;
break;
case '\\':
$tok = Token::bslash;
break;
case '^':
$tok = Token::carat;
break;
case '$':
$tok = Token::dollar;
break;
case '@':
$tok = Token::at;
break;
}
// Catch all characters that are legal within strings.
if ($tok == -1) {
// TODO: This should be UTF-8 compatible, but PHP doesn't
// have a native UTF-8 string. Should we use external
// mbstring library?
$ord = ord($ch);
// Characters in this pool are legal for use inside of
// certain strings. Extended ASCII is used here, though I
// Don't know if these are really legal.
if (($ord >= 32 && $ord <= 126) || ($ord >= 128 && $ord <= 255)) {
$tok = Token::stringLegal;
}
else {
throw new ParseException('Illegal character found in stream: ' . $ord);
}
}
$this->token = $tok;
return $tok;
}
/**
* Get a name string from the input stream.
* A name string must be composed of
* only characters defined in Token:char: -_a-zA-Z0-9
*/
public function getNameString() {
$buf = '';
while ($this->token === Token::char) {
$buf .= $this->value;
$this->nextToken();
//print '_';
}
return $buf;
}
/**
* This gets a string with any legal 'string' characters.
* See CSS Selectors specification, section 11, for the
* definition of string.
*
* This will check for string1, string2, and the case where a
* string is unquoted (Oddly absent from the "official" grammar,
* though such strings are present as examples in the spec.)
*
* Note:
* Though the grammar supplied by CSS 3 Selectors section 11 does not
* address the contents of a pseudo-class value, the spec itself indicates
* that a pseudo-class value is a "value between parenthesis" [6.6]. The
* examples given use URLs among other things, making them closer to the
* definition of 'string' than to 'name'. So we handle them here as strings.
*/
public function getQuotedString() {
if ($this->token == Token::quote || $this->token == Token::squote || $this->token == Token::lparen) {
$end = ($this->token == Token::lparen) ? Token::rparen : $this->token;
$buf = '';
$escape = FALSE;
$this->nextToken(); // Skip the opening quote/paren
// The second conjunct is probably not necessary.
while ($this->token !== FALSE && $this->token > -1) {
//print "Char: $this->value \n";
if ($this->token == Token::bslash && !$escape) {
// XXX: The backslash (\) is removed here.
// Turn on escaping.
//$buf .= $this->value;
$escape = TRUE;
}
elseif ($escape) {
// Turn off escaping
$buf .= $this->value;
$escape = FALSE;
}
elseif ($this->token === $end) {
// At end of string; skip token and break.
$this->nextToken();
break;
}
else {
// Append char.
$buf .= $this->value;
}
$this->nextToken();
}
return $buf;
}
}
// Get the contents inside of a pseudoClass().
public function getPseudoClassString() {
if ($this->token == Token::quote || $this->token == Token::squote || $this->token == Token::lparen) {
$end = ($this->token == Token::lparen) ? Token::rparen : $this->token;
$buf = '';
$escape = FALSE;
$this->nextToken(); // Skip the opening quote/paren
// The second conjunct is probably not necessary.
while ($this->token !== FALSE && $this->token > -1) {
//print "Char: $this->value \n";
if ($this->token == Token::bslash && !$escape) {
// XXX: The backslash (\) is removed here.
// Turn on escaping.
//$buf .= $this->value;
$escape = TRUE;
}
elseif ($escape) {
// Turn off escaping
$buf .= $this->value;
$escape = FALSE;
}
// Allow nested pseudoclasses.
elseif ($this->token == Token::lparen) {
$buf .= "(";
$buf .= $this->getPseudoClassString();
$buf .= ")";
}
elseif ($this->token === $end) {
// At end of string; skip token and break.
$this->nextToken();
break;
}
else {
// Append char.
$buf .= $this->value;
}
$this->nextToken();
}
return $buf;
}
}
/**
* Get a string from the input stream.
* This is a convenience function for getting a string of
* characters that are either alphanumber or whitespace. See
* the Token::white and Token::char definitions.
*
* @deprecated This is not used anywhere in QueryPath.
*//*
public function getStringPlusWhitespace() {
$buf = '';
if($this->token === FALSE) {return '';}
while ($this->token === Token::char || $this->token == Token::white) {
$buf .= $this->value;
$this->nextToken();
}
return $buf;
}*/
}