<?php
/**
* Token utilities.
*
* @package SqlParser
* @subpackage Utils
*/
namespace SqlParser\Utils;
use SqlParser\Lexer;
use SqlParser\Token;
use SqlParser\TokensList;
/**
* Token utilities.
*
* @category Token
* @package SqlParser
* @subpackage Utils
* @author Dan Ungureanu <udan1107@gmail.com>
* @license http://opensource.org/licenses/GPL-2.0 GNU Public License
*/
class Tokens
{
/**
* Checks if a pattern is a match for the specified token.
*
* @param Token $token The token to be matched.
* @param array $pattern The pattern to be matches.
*
* @return bool
*/
public static function match(Token $token, array $pattern)
{
// Token.
if ((isset($pattern['token']))
&& ($pattern['token'] !== $token->token)
) {
return false;
}
// Value.
if ((isset($pattern['value']))
&& ($pattern['value'] !== $token->value)
) {
return false;
}
if ((isset($pattern['value_str']))
&& (strcasecmp($pattern['value_str'], $token->value))
) {
return false;
}
// Type.
if ((isset($pattern['type']))
&& ($pattern['type'] !== $token->type)
) {
return false;
}
// Flags.
if ((isset($pattern['flags']))
&& (($pattern['flags'] & $token->flags) === 0)
) {
return false;
}
return true;
}
public static function replaceTokens($list, array $find, array $replace)
{
/**
* Whether the first parameter is a list.
*
* @var bool
*/
$isList = $list instanceof TokensList;
// Parsing the tokens.
if (!$isList) {
$list = Lexer::getTokens($list);
}
/**
* The list to be returned.
*
* @var array
*/
$newList = array();
/**
* The length of the find pattern is calculated only once.
*
* @var int
*/
$findCount = count($find);
/**
* The starting index of the pattern.
*
* @var int
*/
$i = 0;
while ($i < $list->count) {
// A sequence may not start with a comment.
if ($list->tokens[$i]->type === Token::TYPE_COMMENT) {
$newList[] = $list->tokens[$i];
++$i;
continue;
}
/**
* The index used to parse `$list->tokens`.
*
* This index might be running faster than `$k` because some tokens
* are skipped.
*
* @var int
*/
$j = $i;
/**
* The index used to parse `$find`.
*
* This index might be running slower than `$j` because some tokens
* are skipped.
*
* @var int
*/
$k = 0;
// Checking if the next tokens match the pattern described.
while (($j < $list->count) && ($k < $findCount)) {
// Comments are being skipped.
if ($list->tokens[$j]->type === Token::TYPE_COMMENT) {
++$j;
}
if (!static::match($list->tokens[$j], $find[$k])) {
// This token does not match the pattern.
break;
}
// Going to next token and segment of find pattern.
++$j;
++$k;
}
// Checking if the sequence was found.
if ($k === $findCount) {
// Inserting new tokens.
foreach ($replace as $token) {
$newList[] = $token;
}
// Skipping next `$findCount` tokens.
$i = $j;
} else {
// Adding the same token.
$newList[] = $list->tokens[$i];
++$i;
}
}
return $isList ?
new TokensList($newList) : TokensList::build($newList);
}
}
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