File Source for Lexer.php

<?php
/**
* PHP_LexerGenerator, a php 5 lexer generator.
*
* This lexer generator translates a file in a format similar to
* re2c ({@link http://re2c.org}) and translates it into a PHP 5-based lexer
*
* PHP version 5
*
* LICENSE: This source file is subject to version 3.01 of the PHP license
* that is available through the world-wide-web at the following URI:
* http://www.php.net/license/3_01.txt. If you did not receive a copy of
* the PHP License and are unable to obtain it through the web, please
* send a note to license@php.net so we can mail you a copy immediately.
*
* @category php
* @package PHP_LexerGenerator
* @author Gregory Beaver <cellog@php.net>
* @copyright 2006 Gregory Beaver
* @license http://www.php.net/license/3_01.txt PHP License 3.01
* @version CVS: $Id$
* @since File available since Release 0.1.0
*/
require_once 'PHP/LexerGenerator/Parser.php';
/**
* Token scanner for plex files.
*
* This scanner detects comments beginning with "/*!lex2php" and
* then returns their components (processing instructions, patterns, strings
* action code, and regexes)
* @package PHP_LexerGenerator
* @author Gregory Beaver <cellog@php.net>
* @copyright 2006 Gregory Beaver
* @license http://www.php.net/license/3_01.txt PHP License 3.01
* @version @package_version@
* @since Class available since Release 0.1.0
*/
class PHP_LexerGenerator_Lexer
{
private $data;
private $N;
private $state;
/**
* Current line number in input
* @var int
*/
public $line;
/**
* Number of scanning errors detected
* @var int
*/
public $errors = 0;
/**
* integer identifier of the current token
* @var int
*/
public $token;
/**
* string content of current token
* @var string
*/
public $value;
const PHPCODE = PHP_LexerGenerator_Parser::PHPCODE;
const COMMENTSTART = PHP_LexerGenerator_Parser::COMMENTSTART;
const COMMENTEND = PHP_LexerGenerator_Parser::COMMENTEND;
const QUOTE = PHP_LexerGenerator_Parser::QUOTE;
const PATTERN = PHP_LexerGenerator_Parser::PATTERN;
const CODE = PHP_LexerGenerator_Parser::CODE;
const SUBPATTERN = PHP_LexerGenerator_Parser::SUBPATTERN;
const PI = PHP_LexerGenerator_Parser::PI;
/**
* prepare scanning
* @param string the input
*/
function __construct($data)
{
$this->data = str_replace("\r\n", "\n", $data);
$this->N = 0;
$this->line = 1;
$this->state = 'Start';
$this->errors = 0;
}
/**
* Output an error message
* @param string
*/
private function error($msg)
{
echo 'Error on line ' . $this->line . ': ' . $msg;
$this->errors++;
}
/**
* Initial scanning state lexer
* @return boolean
*/
private function lexStart()
{
if ($this->N >= strlen($this->data)) {
return false;
}
$a = strpos($this->data, '/*!lex2php' . "\n", $this->N);
if ($a === false) {
$this->value = substr($this->data, $this->N);
$this->N = strlen($this->data);
$this->token = self::PHPCODE;
return true;
}
if ($a > $this->N) {
$this->value = substr($this->data, $this->N, $a - $this->N);
$this->N = $a;
$this->token = self::PHPCODE;
return true;
}
$this->value = '/*!lex2php' . "\n";
$this->N += 11; // strlen("/*lex2php\n")
$this->token = self::COMMENTSTART;
$this->state = 'Declare';
return true;
}
/**
* lexer for top-level canning state after the initial declaration comment
* @return boolean
*/
private function lexStartNonDeclare()
{
if ($this->N >= strlen($this->data)) {
return false;
}
$a = strpos($this->data, '/*!lex2php' . "\n", $this->N);
if ($a === false) {
$this->value = substr($this->data, $this->N);
$this->N = strlen($this->data);
$this->token = self::PHPCODE;
return true;
}
if ($a > $this->N) {
$this->value = substr($this->data, $this->N, $a - $this->N);
$this->N = $a;
$this->token = self::PHPCODE;
return true;
}
$this->value = '/*!lex2php' . "\n";
$this->N += 11; // strlen("/*lex2php\n")
$this->token = self::COMMENTSTART;
$this->state = 'Rule';
return true;
}
/**
* lexer for declaration comment state
* @return boolean
*/
private function lexDeclare()
{
if ($this->data[$this->N] == '*' && $this->data[$this->N + 1] == '/') {
$this->state = 'StartNonDeclare';
$this->value = '*/';
$this->N += 2;
$this->token = self::COMMENTEND;
return true;
}
if (preg_match('/^%([a-z]+)/', substr($this->data, $this->N), $token)) {
$this->value = $token[1];
$this->N += strlen($token[1]) + 1;
$this->state = 'DeclarePI';
$this->token = self::PI;
return true;
}
if (preg_match('/^[a-zA-Z_]+/', substr($this->data, $this->N), $token)) {
$this->value = $token[0];
$this->token = self::PATTERN;
$this->N += strlen($token[0]);
$this->state = 'DeclareEquals';
return true;
} else {
$this->error('expecting declaration of sub-patterns');
return false;
}
}
/**
* lexer for processor instructions within declaration comment
* @return boolean
*/
private function lexDeclarePI()
{
while ($this->N < strlen($this->data) &&
($this->data[$this->N] == ' ' ||
$this->data[$this->N] == "\t")) {
$this->N++; // skip whitespace
}
if ($this->data[$this->N] == "\n") {
$this->N++;
$this->state = 'Declare';
$this->line++;
return $this->lexDeclare();
}
if ($this->data[$this->N] == '{') {
return $this->lexCode();
}
if (!preg_match("/[^\n]+/", substr($this->data, $this->N), $token)) {
$this->error('Unexpected end of file');
return false;
}
$this->value = $token[0];
$this->N += strlen($this->value);
$this->token = self::SUBPATTERN;
return true;
}
/**
* lexer for processor instructions inside rule comments
* @return boolean
*/
private function lexDeclarePIRule()
{
while ($this->N < strlen($this->data) &&
($this->data[$this->N] == ' ' ||
$this->data[$this->N] == "\t")) {
$this->N++; // skip whitespace
}
if ($this->data[$this->N] == "\n") {
$this->N++;
$this->state = 'Rule';
$this->line++;
return $this->lexRule();
}
if ($this->data[$this->N] == '{') {
return $this->lexCode();
}
if (!preg_match("/[^\n]+/", substr($this->data, $this->N), $token)) {
$this->error('Unexpected end of file');
return false;
}
$this->value = $token[0];
$this->N += strlen($this->value);
$this->token = self::SUBPATTERN;
return true;
}
/**
* lexer for the state representing scanning between a pattern and the "=" sign
* @return boolean
*/
private function lexDeclareEquals()
{
while ($this->N < strlen($this->data) &&
($this->data[$this->N] == ' ' || $this->data[$this->N] == "\t")) {
$this->N++; // skip whitespace
}
if ($this->N >= strlen($this->data)) {
$this->error('unexpected end of input, expecting "=" for sub-pattern declaration');
}
if ($this->data[$this->N] != '=') {
$this->error('expecting "=" for sub-pattern declaration');
return false;
}
$this->N++;
$this->state = 'DeclareRightside';
while ($this->N < strlen($this->data) &&
($this->data[$this->N] == ' ' || $this->data[$this->N] == "\t")) {
$this->N++; // skip whitespace
}
if ($this->N >= strlen($this->data)) {
$this->error('unexpected end of file, expecting right side of sub-pattern declaration');
return false;
}
return $this->lexDeclareRightside();
}
/**
* lexer for the right side of a pattern, detects quotes or regexes
* @return boolean
*/
private function lexDeclareRightside()
{
if ($this->data[$this->N] == "\n") {
$this->state = 'lexDeclare';
$this->N++;
$this->line++;
return $this->lexDeclare();
}
if ($this->data[$this->N] == '"') {
return $this->lexQuote();
}
while ($this->N < strlen($this->data) &&
($this->data[$this->N] == ' ' ||
$this->data[$this->N] == "\t")) {
$this->N++; // skip all whitespace
}
// match a pattern
$test = $this->data[$this->N];
$token = $this->N + 1;
$a = 0;
do {
if ($a++) {
$token++;
}
$token = strpos($this->data, $test, $token);
} while ($token !== false && ($this->data[$token - 1] == '\\'
&& $this->data[$token - 2] != '\\'));
if ($token === false) {
$this->error('Unterminated regex pattern (started with "' . $test . '"');
return false;
}
if (substr_count($this->data, "\n", $this->N, $token - $this->N)) {
$this->error('Regex pattern extends over multiple lines');
return false;
}
$this->value = substr($this->data, $this->N + 1, $token - $this->N - 1);
// unescape the regex marker
// we will re-escape when creating the final regex
$this->value = str_replace('\\' . $test, $test, $this->value);
$this->N = $token + 1;
$this->token = self::SUBPATTERN;
return true;
}
/**
* lexer for quoted literals
* @return boolean
*/
private function lexQuote()
{
$token = $this->N + 1;
$a = 0;
do {
if ($a++) {
$token++;
}
$token = strpos($this->data, '"', $token);
} while ($token !== false && $token < strlen($this->data) &&
($this->data[$token - 1] == '\\' && $this->data[$token - 2] != '\\'));
if ($token === false) {
$this->error('unterminated quote');
return false;
}
if (substr_count($this->data, "\n", $this->N, $token - $this->N)) {
$this->error('quote extends over multiple lines');
return false;
}
$this->value = substr($this->data, $this->N + 1, $token - $this->N - 1);
$this->value = str_replace('\\"', '"', $this->value);
$this->value = str_replace('\\\\', '\\', $this->value);
$this->N = $token + 1;
$this->token = self::QUOTE;
return true;
}
/**
* lexer for rules
* @return boolean
*/
private function lexRule()
{
while ($this->N < strlen($this->data) &&
($this->data[$this->N] == ' ' ||
$this->data[$this->N] == "\t" ||
$this->data[$this->N] == "\n")) {
if ($this->data[$this->N] == "\n") {
$this->line++;
}
$this->N++; // skip all whitespace
}
if ($this->N >= strlen($this->data)) {
$this->error('unexpected end of input, expecting rule declaration');
}
if ($this->data[$this->N] == '*' && $this->data[$this->N + 1] == '/') {
$this->state = 'StartNonDeclare';
$this->value = '*/';
$this->N += 2;
$this->token = self::COMMENTEND;
return true;
}
if (preg_match('/^%([a-z]+)/', substr($this->data, $this->N), $token)) {
$this->value = $token[1];
$this->N += strlen($token[1]) + 1;
$this->state = 'DeclarePIRule';
$this->token = self::PI;
return true;
}
if ($this->data[$this->N] == "{") {
return $this->lexCode();
}
if ($this->data[$this->N] == '"') {
return $this->lexQuote();
}
if (preg_match('/^[a-zA-Z_]+/', substr($this->data, $this->N), $token)) {
$this->value = $token[0];
$this->N += strlen($token[0]);
$this->token = self::SUBPATTERN;
return true;
} else {
$this->error('expecting token rule (quotes or sub-patterns)');
return false;
}
}
/**
* lexer for php code blocks
* @return boolean
*/
private function lexCode()
{
$cp = $this->N + 1;
for ($level = 1; $cp < strlen($this->data) && ($level > 1 || $this->data[$cp] != '}'); $cp++) {
if ($this->data[$cp] == '{') {
$level++;
} elseif ($this->data[$cp] == '}') {
$level--;
} elseif ($this->data[$cp] == '/' && $this->data[$cp + 1] == '/') {
/* Skip C++ style comments */
$cp += 2;
$z = strpos($this->data, "\n", $cp);
if ($z === false) {
$cp = strlen($this->data);
break;
}
$cp = $z;
} elseif ($this->data[$cp] == "'" || $this->data[$cp] == '"') {
/* String a character literals */
$startchar = $this->data[$cp];
$prevc = 0;
for ($cp++; $cp < strlen($this->data) && ($this->data[$cp] != $startchar || $prevc === '\\'); $cp++) {
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Source for file Lexer.php