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<?php
/**
* This file is part of PDepend.
*
* PHP Version 5
*
* Copyright (c) 2008-2017 Manuel Pichler <mapi@pdepend.org>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* * Neither the name of Manuel Pichler nor the names of his
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* @copyright 2008-2017 Manuel Pichler. All rights reserved.
* @license http://www.opensource.org/licenses/bsd-license.php BSD License
*/
namespace PDepend\Source\Parser;
/**
* This class provides a simple hashmap for name mappings done by the parser.
*
* @copyright 2008-2017 Manuel Pichler. All rights reserved.
* @license http://www.opensource.org/licenses/bsd-license.php BSD License
*/
class SymbolTable
{
/**
* Stack with all active scopes.
*
* @var array<array<string, string>>
*/
private $scopeStack = array();
/**
* The currently active scope.
*
* @var array<string, string>|null
*/
private $scope = array();
/**
* This method creates a new scope.
*
* @return void
*/
public function createScope()
{
// Add copy of last scope as new scope
array_push($this->scopeStack, $this->scope);
}
/**
* This method destroys the top most scope.
*
* @throws NoActiveScopeException
*
* @return void
*/
public function destroyScope()
{
$this->ensureActiveScopeExists();
// Destroy current active scope
$this->scope = null;
// Try to restore previously active scope
if (count($this->scopeStack) > 0) {
$this->scope = array_pop($this->scopeStack);
}
}
/**
* Adds a new value to the top most scope.
*
* @param string $key The key of this scope value.
* @param mixed $value A new scope value.
*
* @throws NoActiveScopeException
*
* @return void
*/
public function add($key, $value)
{
$this->ensureActiveScopeExists();
$this->scope[$this->normalizeKey($key)] = $value;
}
/**
* Resets the current scope
*
* @throws NoActiveScopeException
*
* @return void
*/
public function resetScope()
{
$this->ensureActiveScopeExists();
$this->scope = array();
}
/**
* This method will return the registered value for the given key, when it
* exists in the current scope. The returned value will <b>null</b> if no
* value exists for the given key.
*
* @param string $key The key for a searched scope value.
*
* @throws NoActiveScopeException
*
* @return string|null
*/
public function lookup($key)
{
$this->ensureActiveScopeExists();
$normalizedKey = $this->normalizeKey($key);
return isset($this->scope[$normalizedKey])
? $this->scope[$normalizedKey]
: null;
}
/**
* Checks if there is an active scope.
*
* @throws NoActiveScopeException if no active scope exists.
*
* @return void
*/
private function ensureActiveScopeExists()
{
if (null === $this->scope) {
throw new NoActiveScopeException();
}
}
/**
* Normalizes the <code>$key</code>, so it's the same for
* <code>add()</code> and <code>lookup()</code> operations.
*
* @param string $key
*
* @return string normalized key
*/
private function normalizeKey($key)
{
return strtolower($key);
}
}