<?php

if (!defined('ENT_SUBSTITUTE')) {
    define('ENT_SUBSTITUTE', 8);
}

/*
 * This file is part of Twig.
 *
 * (c) 2009 Fabien Potencier
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
class Twig_Extension_Core extends Twig_Extension
{
    protected $dateFormats = array('F j, Y H:i', '%d days');
    protected $numberFormat = array(0, '.', ',');
    protected $timezone = null;

    /**
     * Sets the default format to be used by the date filter.
     *
     * @param string $format             The default date format string
     * @param string $dateIntervalFormat The default date interval format string
     */
    public function setDateFormat($format = null, $dateIntervalFormat = null)
    {
        if (null !== $format) {
            $this->dateFormats[0] = $format;
        }

        if (null !== $dateIntervalFormat) {
            $this->dateFormats[1] = $dateIntervalFormat;
        }
    }

    /**
     * Gets the default format to be used by the date filter.
     *
     * @return array The default date format string and the default date interval format string
     */
    public function getDateFormat()
    {
        return $this->dateFormats;
    }

    /**
     * Sets the default timezone to be used by the date filter.
     *
     * @param DateTimeZone|string $timezone  The default timezone string or a DateTimeZone object
     */
    public function setTimezone($timezone)
    {
        $this->timezone = $timezone instanceof DateTimeZone ? $timezone : new DateTimeZone($timezone);
    }

    /**
     * Gets the default timezone to be used by the date filter.
     *
     * @return DateTimeZone The default timezone currently in use
     */
    public function getTimezone()
    {
        return $this->timezone;
    }

    /**
     * Sets the default format to be used by the number_format filter.
     *
     * @param integer $decimal The number of decimal places to use.
     * @param string $decimalPoint The character(s) to use for the decimal point.
     * @param string $thousandSep The character(s) to use for the thousands separator.
     */
    public function setNumberFormat($decimal, $decimalPoint, $thousandSep)
    {
        $this->numberFormat = array($decimal, $decimalPoint, $thousandSep);
    }

    /**
     * Get the default format used by the number_format filter.
     *
     * @return array The arguments for number_format()
     */
    public function getNumberFormat()
    {
        return $this->numberFormat;
    }

    /**
     * Returns the token parser instance to add to the existing list.
     *
     * @return array An array of Twig_TokenParser instances
     */
    public function getTokenParsers()
    {
        return array(
            new Twig_TokenParser_For(),
            new Twig_TokenParser_If(),
            new Twig_TokenParser_Extends(),
            new Twig_TokenParser_Include(),
            new Twig_TokenParser_Block(),
            new Twig_TokenParser_Use(),
            new Twig_TokenParser_Filter(),
            new Twig_TokenParser_Macro(),
            new Twig_TokenParser_Import(),
            new Twig_TokenParser_From(),
            new Twig_TokenParser_Set(),
            new Twig_TokenParser_Spaceless(),
            new Twig_TokenParser_Flush(),
            new Twig_TokenParser_Do(),
        );
    }

    /**
     * Returns a list of filters to add to the existing list.
     *
     * @return array An array of filters
     */
    public function getFilters()
    {
        $filters = array(
            // formatting filters
            'date'          => new Twig_Filter_Function('twig_date_format_filter', array('needs_environment' => true)),
            'format'        => new Twig_Filter_Function('sprintf'),
            'replace'       => new Twig_Filter_Function('strtr'),
            'number_format' => new Twig_Filter_Function('twig_number_format_filter', array('needs_environment' => true)),

            // encoding
            'url_encode'       => new Twig_Filter_Function('twig_urlencode_filter'),
            'json_encode'      => new Twig_Filter_Function('twig_jsonencode_filter'),
            'convert_encoding' => new Twig_Filter_Function('twig_convert_encoding'),

            // string filters
            'title'      => new Twig_Filter_Function('twig_title_string_filter', array('needs_environment' => true)),
            'capitalize' => new Twig_Filter_Function('twig_capitalize_string_filter', array('needs_environment' => true)),
            'upper'      => new Twig_Filter_Function('strtoupper'),
            'lower'      => new Twig_Filter_Function('strtolower'),
            'striptags'  => new Twig_Filter_Function('strip_tags'),
            'nl2br'      => new Twig_Filter_Function('nl2br', array('pre_escape' => 'html', 'is_safe' => array('html'))),

            // array helpers
            'join'    => new Twig_Filter_Function('twig_join_filter'),
            'sort'    => new Twig_Filter_Function('twig_sort_filter'),
            'merge'   => new Twig_Filter_Function('twig_array_merge'),

            // string/array filters
            'reverse' => new Twig_Filter_Function('twig_reverse_filter', array('needs_environment' => true)),
            'length'  => new Twig_Filter_Function('twig_length_filter', array('needs_environment' => true)),
            'slice'   => new Twig_Filter_Function('twig_slice', array('needs_environment' => true)),

            // iteration and runtime
            'default' => new Twig_Filter_Node('Twig_Node_Expression_Filter_Default'),
            '_default' => new Twig_Filter_Function('_twig_default_filter'),

            'keys'    => new Twig_Filter_Function('twig_get_array_keys_filter'),

            // escaping
            'escape' => new Twig_Filter_Function('twig_escape_filter', array('needs_environment' => true, 'is_safe_callback' => 'twig_escape_filter_is_safe')),
            'e'      => new Twig_Filter_Function('twig_escape_filter', array('needs_environment' => true, 'is_safe_callback' => 'twig_escape_filter_is_safe')),
        );

        if (function_exists('mb_get_info')) {
            $filters['upper'] = new Twig_Filter_Function('twig_upper_filter', array('needs_environment' => true));
            $filters['lower'] = new Twig_Filter_Function('twig_lower_filter', array('needs_environment' => true));
        }

        return $filters;
    }

    /**
     * Returns a list of global functions to add to the existing list.
     *
     * @return array An array of global functions
     */
    public function getFunctions()
    {
        return array(
            'range'    => new Twig_Function_Function('range'),
            'constant' => new Twig_Function_Function('constant'),
            'cycle'    => new Twig_Function_Function('twig_cycle'),
            'random'   => new Twig_Function_Function('twig_random', array('needs_environment' => true)),
            'date'     => new Twig_Function_Function('twig_date_converter', array('needs_environment' => true)),
        );
    }

    /**
     * Returns a list of filters to add to the existing list.
     *
     * @return array An array of filters
     */
    public function getTests()
    {
        return array(
            'even'        => new Twig_Test_Node('Twig_Node_Expression_Test_Even'),
            'odd'         => new Twig_Test_Node('Twig_Node_Expression_Test_Odd'),
            'defined'     => new Twig_Test_Node('Twig_Node_Expression_Test_Defined'),
            'sameas'      => new Twig_Test_Node('Twig_Node_Expression_Test_Sameas'),
            'none'        => new Twig_Test_Node('Twig_Node_Expression_Test_Null'),
            'null'        => new Twig_Test_Node('Twig_Node_Expression_Test_Null'),
            'divisibleby' => new Twig_Test_Node('Twig_Node_Expression_Test_Divisibleby'),
            'constant'    => new Twig_Test_Node('Twig_Node_Expression_Test_Constant'),
            'empty'       => new Twig_Test_Function('twig_test_empty'),
        );
    }

    /**
     * Returns a list of operators to add to the existing list.
     *
     * @return array An array of operators
     */
    public function getOperators()
    {
        return array(
            array(
                'not' => array('precedence' => 50, 'class' => 'Twig_Node_Expression_Unary_Not'),
                '-'   => array('precedence' => 500, 'class' => 'Twig_Node_Expression_Unary_Neg'),
                '+'   => array('precedence' => 500, 'class' => 'Twig_Node_Expression_Unary_Pos'),
            ),
            array(
                'b-and'  => array('precedence' => 5, 'class' => 'Twig_Node_Expression_Binary_BitwiseAnd', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'b-xor'  => array('precedence' => 5, 'class' => 'Twig_Node_Expression_Binary_BitwiseXor', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'b-or'   => array('precedence' => 5, 'class' => 'Twig_Node_Expression_Binary_BitwiseOr', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'or'     => array('precedence' => 10, 'class' => 'Twig_Node_Expression_Binary_Or', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'and'    => array('precedence' => 15, 'class' => 'Twig_Node_Expression_Binary_And', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '=='     => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_Equal', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '!='     => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_NotEqual', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '<'      => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_Less', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '>'      => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_Greater', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '>='     => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_GreaterEqual', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '<='     => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_LessEqual', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'not in' => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_NotIn', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'in'     => array('precedence' => 20, 'class' => 'Twig_Node_Expression_Binary_In', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '..'     => array('precedence' => 25, 'class' => 'Twig_Node_Expression_Binary_Range', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '+'      => array('precedence' => 30, 'class' => 'Twig_Node_Expression_Binary_Add', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '-'      => array('precedence' => 30, 'class' => 'Twig_Node_Expression_Binary_Sub', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '~'      => array('precedence' => 40, 'class' => 'Twig_Node_Expression_Binary_Concat', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '*'      => array('precedence' => 60, 'class' => 'Twig_Node_Expression_Binary_Mul', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '/'      => array('precedence' => 60, 'class' => 'Twig_Node_Expression_Binary_Div', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '//'     => array('precedence' => 60, 'class' => 'Twig_Node_Expression_Binary_FloorDiv', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '%'      => array('precedence' => 60, 'class' => 'Twig_Node_Expression_Binary_Mod', 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'is'     => array('precedence' => 100, 'callable' => array($this, 'parseTestExpression'), 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                'is not' => array('precedence' => 100, 'callable' => array($this, 'parseNotTestExpression'), 'associativity' => Twig_ExpressionParser::OPERATOR_LEFT),
                '**'     => array('precedence' => 200, 'class' => 'Twig_Node_Expression_Binary_Power', 'associativity' => Twig_ExpressionParser::OPERATOR_RIGHT),
            ),
        );
    }

    public function parseNotTestExpression(Twig_Parser $parser, $node)
    {
        return new Twig_Node_Expression_Unary_Not($this->parseTestExpression($parser, $node), $parser->getCurrentToken()->getLine());
    }

    public function parseTestExpression(Twig_Parser $parser, $node)
    {
        $stream = $parser->getStream();
        $name = $stream->expect(Twig_Token::NAME_TYPE)->getValue();
        $arguments = null;
        if ($stream->test(Twig_Token::PUNCTUATION_TYPE, '(')) {
            $arguments = $parser->getExpressionParser()->parseArguments();
        }

        $class = $this->getTestNodeClass($parser->getEnvironment(), $name);

        return new $class($node, $name, $arguments, $parser->getCurrentToken()->getLine());
    }

    protected function getTestNodeClass(Twig_Environment $env, $name)
    {
        $testMap = $env->getTests();
        if (isset($testMap[$name]) && $testMap[$name] instanceof Twig_Test_Node) {
            return $testMap[$name]->getClass();
        }

        return 'Twig_Node_Expression_Test';
    }

    /**
     * Returns the name of the extension.
     *
     * @return string The extension name
     */
    public function getName()
    {
        return 'core';
    }
}

/**
 * Cycles over a value.
 *
 * @param ArrayAccess|array $values An array or an ArrayAccess instance
 * @param integer           $i      The cycle value
 *
 * @return string The next value in the cycle
 */
function twig_cycle($values, $i)
{
    if (!is_array($values) && !$values instanceof ArrayAccess) {
        return $values;
    }

    return $values[$i % count($values)];
}

/**
 * Returns a random value depending on the supplied parameter type:
 * - a random item from a Traversable or array
 * - a random character from a string
 * - a random integer between 0 and the integer parameter
 *
 * @param Twig_Environment             $env    A Twig_Environment instance
 * @param Traversable|array|int|string $values The values to pick a random item from
 *
 * @return mixed A random value from the given sequence
 */
function twig_random(Twig_Environment $env, $values = null)
{
    if (null === $values) {
        return mt_rand();
    }

    if (is_int($values) || is_float($values)) {
        return $values < 0 ? mt_rand($values, 0) : mt_rand(0, $values);
    }

    if ($values instanceof Traversable) {
        $values = iterator_to_array($values);
    } elseif (is_string($values)) {
        if (null !== $charset = $env->getCharset()) {
            if ('UTF-8' != $charset) {
                $values = twig_convert_encoding($values, 'UTF-8', $charset);
            }

            // unicode version of str_split()
            // split at all positions, but not after the start and not before the end
            $values = preg_split('/(?<!^)(?!$)/u', $values);

            if ('UTF-8' != $charset) {
                foreach ($values as $i => $value) {
                    $values[$i] = twig_convert_encoding($value, $charset, 'UTF-8');
                }
            }
        } else {
            return $values[mt_rand(0, strlen($values) - 1)];
        }
    }

    if (!is_array($values)) {
        return $values;
    }

    if (0 === count($values)) {
        throw new Twig_Error_Runtime('The random function cannot pick from an empty array.');
    }

    return $values[array_rand($values, 1)];
}

/**
 * Converts a date to the given format.
 *
 * <pre>
 *   {{ post.published_at|date("m/d/Y") }}
 * </pre>
 *
 * @param Twig_Environment             $env      A Twig_Environment instance
 * @param DateTime|DateInterval|string $date     A date
 * @param string                       $format   A format
 * @param DateTimeZone|string          $timezone A timezone
 *
 * @return string The formatter date
 */
function twig_date_format_filter(Twig_Environment $env, $date, $format = null, $timezone = null)
{
    if (null === $format) {
        $formats = $env->getExtension('core')->getDateFormat();
        $format = $date instanceof DateInterval ? $formats[1] : $formats[0];
    }

    if ($date instanceof DateInterval || $date instanceof DateTime) {
        return $date->format($format);
    }

    return twig_date_converter($env, $date, $timezone)->format($format);
}

/**
 * Converts an input to a DateTime instance.
 *
 * <pre>
 *    {% if date(user.created_at) < date('+2days') %}
 *      {# do something #}
 *    {% endif %}
 * </pre>
 *
 * @param Twig_Environment    $env      A Twig_Environment instance
 * @param DateTime|string     $date     A date
 * @param DateTimeZone|string $timezone A timezone
 *
 * @return DateTime A DateTime instance
 */
function twig_date_converter(Twig_Environment $env, $date = null, $timezone = null)
{
    if ($date instanceof DateTime) {
        return $date;
    }

    $asString = (string) $date;

    if (ctype_digit($asString) || (!empty($asString) && '-' === $asString[0] && ctype_digit(substr($asString, 1)))) {
        $date = new DateTime('@'.$date);
        $date->setTimezone(new DateTimeZone(date_default_timezone_get()));
    } else {
        $date = new DateTime($date);
    }

    // set Timezone
    if (null !== $timezone) {
        if (!$timezone instanceof DateTimeZone) {
            $timezone = new DateTimeZone($timezone);
        }

        $date->setTimezone($timezone);
    } elseif (($timezone = $env->getExtension('core')->getTimezone()) instanceof DateTimeZone) {
        $date->setTimezone($timezone);
    }

    return $date;
}

/**
 * Number format filter.
 *
 * All of the formatting options can be left null, in that case the defaults will
 * be used.  Supplying any of the parameters will override the defaults set in the
 * environment object.
 *
 * @param Twig_Environment    $env          A Twig_Environment instance
 * @param mixed               $number       A float/int/string of the number to format
 * @param int                 $decimal      The number of decimal points to display.
 * @param string              $decimalPoint The character(s) to use for the decimal point.
 * @param string              $thousandSep  The character(s) to use for the thousands separator.
 *
 * @return string The formatted number
 */
function twig_number_format_filter(Twig_Environment $env, $number, $decimal = null, $decimalPoint = null, $thousandSep = null)
{
    $defaults = $env->getExtension('core')->getNumberFormat();
    if (null === $decimal) {
        $decimal = $defaults[0];
    }

    if (null === $decimalPoint) {
        $decimalPoint = $defaults[1];
    }

    if (null === $thousandSep) {
        $thousandSep = $defaults[2];
    }

    return number_format((float) $number, $decimal, $decimalPoint, $thousandSep);
}

/**
 * URL encodes a string.
 *
 * @param string $url A URL
 * @param bool   $raw true to use rawurlencode() instead of urlencode
 *
 * @return string The URL encoded value
 */
function twig_urlencode_filter($url, $raw = false)
{
    if ($raw) {
        return rawurlencode($url);
    }

    return urlencode($url);
}

if (version_compare(PHP_VERSION, '5.3.0', '<')) {
    /**
     * JSON encodes a variable.
     *
     * @param mixed   $value   The value to encode.
     * @param integer $options Not used on PHP 5.2.x
     *
     * @return mixed The JSON encoded value
     */
    function twig_jsonencode_filter($value, $options = 0)
    {
        if ($value instanceof Twig_Markup) {
            $value = (string) $value;
        } elseif (is_array($value)) {
            array_walk_recursive($value, '_twig_markup2string');
        }

        return json_encode($value);
    }
} else {
    /**
     * JSON encodes a variable.
     *
     * @param mixed   $value   The value to encode.
     * @param integer $options Bitmask consisting of JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT
     *
     * @return mixed The JSON encoded value
     */
    function twig_jsonencode_filter($value, $options = 0)
    {
        if ($value instanceof Twig_Markup) {
            $value = (string) $value;
        } elseif (is_array($value)) {
            array_walk_recursive($value, '_twig_markup2string');
        }

        return json_encode($value, $options);
    }
}

function _twig_markup2string(&$value)
{
    if ($value instanceof Twig_Markup) {
        $value = (string) $value;
    }
}

/**
 * Merges an array with another one.
 *
 * <pre>
 *  {% set items = { 'apple': 'fruit', 'orange': 'fruit' } %}
 *
 *  {% set items = items|merge({ 'peugeot': 'car' }) %}
 *
 *  {# items now contains { 'apple': 'fruit', 'orange': 'fruit', 'peugeot': 'car' } #}
 * </pre>
 *
 * @param array $arr1 An array
 * @param array $arr2 An array
 *
 * @return array The merged array
 */
function twig_array_merge($arr1, $arr2)
{
    if (!is_array($arr1) || !is_array($arr2)) {
        throw new Twig_Error_Runtime('The merge filter only works with arrays or hashes.');
    }

    return array_merge($arr1, $arr2);
}

/**
 * Slices a variable.
 *
 * @param Twig_Environment $env    A Twig_Environment instance
 * @param mixed            $item   A variable
 * @param integer          $start  Start of the slice
 * @param integer          $length Size of the slice
 *
 * @return mixed The sliced variable
 */
function twig_slice(Twig_Environment $env, $item, $start, $length = null)
{
    if ($item instanceof Traversable) {
        $item = iterator_to_array($item, false);
    }

    if (is_array($item)) {
        return array_slice($item, $start, $length);
    }

    $item = (string) $item;

    if (function_exists('mb_get_info') && null !== $charset = $env->getCharset()) {
        return mb_substr($item, $start, null === $length ? mb_strlen($item, $charset) - $start : $length, $charset);
    }

    return null === $length ? substr($item, $start) : substr($item, $start, $length);
}

/**
 * Joins the values to a string.
 *
 * The separator between elements is an empty string per default, you can define it with the optional parameter.
 *
 * <pre>
 *  {{ [1, 2, 3]|join('|') }}
 *  {# returns 1|2|3 #}
 *
 *  {{ [1, 2, 3]|join }}
 *  {# returns 123 #}
 * </pre>
 *
 * @param array  $value An array
 * @param string $glue  The separator
 *
 * @return string The concatenated string
 */
function twig_join_filter($value, $glue = '')
{
    if ($value instanceof Traversable) {
        $value = iterator_to_array($value, false);
    }

    return implode($glue, (array) $value);
}

// The '_default' filter is used internally to avoid using the ternary operator
// which costs a lot for big contexts (before PHP 5.4). So, on average,
// a function call is cheaper.
function _twig_default_filter($value, $default = '')
{
    if (twig_test_empty($value)) {
        return $default;
    }

    return $value;
}

/**
 * Returns the keys for the given array.
 *
 * It is useful when you want to iterate over the keys of an array:
 *
 * <pre>
 *  {% for key in array|keys %}
 *      {# ... #}
 *  {% endfor %}
 * </pre>
 *
 * @param array $array An array
 *
 * @return array The keys
 */
function twig_get_array_keys_filter($array)
{
    if (is_object($array) && $array instanceof Traversable) {
        return array_keys(iterator_to_array($array));
    }

    if (!is_array($array)) {
        return array();
    }

    return array_keys($array);
}

/**
 * Reverses a variable.
 *
 * @param Twig_Environment         $env          A Twig_Environment instance
 * @param array|Traversable|string $item         An array, a Traversable instance, or a string
 * @param Boolean                  $preserveKeys Whether to preserve key or not
 *
 * @return mixed The reversed input
 */
function twig_reverse_filter(Twig_Environment $env, $item, $preserveKeys = false)
{
    if (is_object($item) && $item instanceof Traversable) {
        return array_reverse(iterator_to_array($item), $preserveKeys);
    }

    if (is_array($item)) {
        return array_reverse($item, $preserveKeys);
    }

    if (null !== $charset = $env->getCharset()) {
        $string = (string) $item;

        if ('UTF-8' != $charset) {
            $item = twig_convert_encoding($string, 'UTF-8', $charset);
        }

        preg_match_all('/./us', $item, $matches);

        $string = implode('', array_reverse($matches[0]));

        if ('UTF-8' != $charset) {
            $string = twig_convert_encoding($string, $charset, 'UTF-8');
        }

        return $string;
    }

    return strrev((string) $item);
}

/**
 * Sorts an array.
 *
 * @param array $array An array
 */
function twig_sort_filter($array)
{
    asort($array);

    return $array;
}

/* used internally */
function twig_in_filter($value, $compare)
{
    if (is_array($compare)) {
        return in_array($value, $compare);
    } elseif (is_string($compare)) {
        if (!strlen((string) $value)) {
            return empty($compare);
        }

        return false !== strpos($compare, (string) $value);
    } elseif (is_object($compare) && $compare instanceof Traversable) {
        return in_array($value, iterator_to_array($compare, false));
    }

    return false;
}

/**
 * Escapes a string.
 *
 * @param Twig_Environment $env        A Twig_Environment instance
 * @param string           $string     The value to be escaped
 * @param string           $type       The escaping strategy
 * @param string           $charset    The charset
 * @param Boolean          $autoescape Whether the function is called by the auto-escaping feature (true) or by the developer (false)
 */
function twig_escape_filter(Twig_Environment $env, $string, $type = 'html', $charset = null, $autoescape = false)
{
    if ($autoescape && is_object($string) && $string instanceof Twig_Markup) {
        return $string;
    }

    if (!is_string($string) && !(is_object($string) && method_exists($string, '__toString'))) {
        return $string;
    }

    if (null === $charset) {
        $charset = $env->getCharset();
    }

    $string = (string) $string;

    switch ($type) {
        case 'js':
            // escape all non-alphanumeric characters
            // into their \xHH or \uHHHH representations
            if ('UTF-8' != $charset) {
                $string = twig_convert_encoding($string, 'UTF-8', $charset);
            }

            if (null === $string = preg_replace_callback('#[^\p{L}\p{N} ]#u', '_twig_escape_js_callback', $string)) {
                throw new Twig_Error_Runtime('The string to escape is not a valid UTF-8 string.');
            }

            if ('UTF-8' != $charset) {
                $string = twig_convert_encoding($string, $charset, 'UTF-8');
            }

            return $string;

        case 'html':
            // see http://php.net/htmlspecialchars

            // Using a static variable to avoid initializing the array
            // each time the function is called. Moving the declaration on the
            // top of the function slow downs other escaping types.
            static $htmlspecialcharsCharsets = array(
                'iso-8859-1' => true, 'iso8859-1' => true,
                'iso-8859-15' => true, 'iso8859-15' => true,
                'utf-8' => true,
                'cp866' => true, 'ibm866' => true, '866' => true,
                'cp1251' => true, 'windows-1251' => true, 'win-1251' => true,
                '1251' => true,
                'cp1252' => true, 'windows-1252' => true, '1252' => true,
                'koi8-r' => true, 'koi8-ru' => true, 'koi8r' => true,
                'big5' => true, '950' => true,
                'gb2312' => true, '936' => true,
                'big5-hkscs' => true,
                'shift_jis' => true, 'sjis' => true, '932' => true,
                'euc-jp' => true, 'eucjp' => true,
                'iso8859-5' => true, 'iso-8859-5' => true, 'macroman' => true,
            );

            if (isset($htmlspecialcharsCharsets[strtolower($charset)])) {
                return htmlspecialchars($string, ENT_QUOTES | ENT_SUBSTITUTE, $charset);
            }

            $string = twig_convert_encoding($string, 'UTF-8', $charset);
            $string = htmlspecialchars($string, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');

            return twig_convert_encoding($string, $charset, 'UTF-8');

        default:
            throw new Twig_Error_Runtime(sprintf('Invalid escape type "%s".', $type));
    }
}

/* used internally */
function twig_escape_filter_is_safe(Twig_Node $filterArgs)
{
    foreach ($filterArgs as $arg) {
        if ($arg instanceof Twig_Node_Expression_Constant) {
            return array($arg->getAttribute('value'));
        }

        return array();
    }

    return array('html');
}

if (function_exists('iconv')) {
    function twig_convert_encoding($string, $to, $from)
    {
        return iconv($from, $to, $string);
    }
} elseif (function_exists('mb_convert_encoding')) {
    function twig_convert_encoding($string, $to, $from)
    {
        return mb_convert_encoding($string, $to, $from);
    }
} else {
    function twig_convert_encoding($string, $to, $from)
    {
        throw new Twig_Error_Runtime('No suitable convert encoding function (use UTF-8 as your encoding or install the iconv or mbstring extension).');
    }
}

function _twig_escape_js_callback($matches)
{
    $char = $matches[0];

    // \xHH
    if (!isset($char[1])) {
        return '\\x'.substr('00'.bin2hex($char), -2);
    }

    // \uHHHH
    $char = twig_convert_encoding($char, 'UTF-16BE', 'UTF-8');

    return '\\u'.substr('0000'.bin2hex($char), -4);
}

// add multibyte extensions if possible
if (function_exists('mb_get_info')) {
    /**
     * Returns the length of a variable.
     *
     * @param Twig_Environment $env   A Twig_Environment instance
     * @param mixed            $thing A variable
     *
     * @return integer The length of the value
     */
    function twig_length_filter(Twig_Environment $env, $thing)
    {
        return is_scalar($thing) ? mb_strlen($thing, $env->getCharset()) : count($thing);
    }

    /**
     * Converts a string to uppercase.
     *
     * @param Twig_Environment $env    A Twig_Environment instance
     * @param string           $string A string
     *
     * @return string The uppercased string
     */
    function twig_upper_filter(Twig_Environment $env, $string)
    {
        if (null !== ($charset = $env->getCharset())) {
            return mb_strtoupper($string, $charset);
        }

        return strtoupper($string);
    }

    /**
     * Converts a string to lowercase.
     *
     * @param Twig_Environment $env    A Twig_Environment instance
     * @param string           $string A string
     *
     * @return string The lowercased string
     */
    function twig_lower_filter(Twig_Environment $env, $string)
    {
        if (null !== ($charset = $env->getCharset())) {
            return mb_strtolower($string, $charset);
        }

        return strtolower($string);
    }

    /**
     * Returns a titlecased string.
     *
     * @param Twig_Environment $env    A Twig_Environment instance
     * @param string           $string A string
     *
     * @return string The titlecased string
     */
    function twig_title_string_filter(Twig_Environment $env, $string)
    {
        if (null !== ($charset = $env->getCharset())) {
            return mb_convert_case($string, MB_CASE_TITLE, $charset);
        }

        return ucwords(strtolower($string));
    }

    /**
     * Returns a capitalized string.
     *
     * @param Twig_Environment $env    A Twig_Environment instance
     * @param string           $string A string
     *
     * @return string The capitalized string
     */
    function twig_capitalize_string_filter(Twig_Environment $env, $string)
    {
        if (null !== ($charset = $env->getCharset())) {
            return mb_strtoupper(mb_substr($string, 0, 1, $charset), $charset).
                         mb_strtolower(mb_substr($string, 1, mb_strlen($string, $charset), $charset), $charset);
        }

        return ucfirst(strtolower($string));
    }
}
// and byte fallback
else
{
    /**
     * Returns the length of a variable.
     *
     * @param Twig_Environment $env   A Twig_Environment instance
     * @param mixed            $thing A variable
     *
     * @return integer The length of the value
     */
    function twig_length_filter(Twig_Environment $env, $thing)
    {
        return is_scalar($thing) ? strlen($thing) : count($thing);
    }

    /**
     * Returns a titlecased string.
     *
     * @param Twig_Environment $env    A Twig_Environment instance
     * @param string           $string A string
     *
     * @return string The titlecased string
     */
    function twig_title_string_filter(Twig_Environment $env, $string)
    {
        return ucwords(strtolower($string));
    }

    /**
     * Returns a capitalized string.
     *
     * @param Twig_Environment $env    A Twig_Environment instance
     * @param string           $string A string
     *
     * @return string The capitalized string
     */
    function twig_capitalize_string_filter(Twig_Environment $env, $string)
    {
        return ucfirst(strtolower($string));
    }
}

/* used internally */
function twig_ensure_traversable($seq)
{
    if (is_array($seq) || (is_object($seq) && $seq instanceof Traversable)) {
        return $seq;
    } else {
        return array();
    }
}

/**
 * Checks if a variable is empty.
 *
 * <pre>
 * {# evaluates to true if the foo variable is null, false, or the empty string #}
 * {% if foo is empty %}
 *     {# ... #}
 * {% endif %}
 * </pre>
 *
 * @param mixed $value A variable
 *
 * @return Boolean true if the value is empty, false otherwise
 */
function twig_test_empty($value)
{
    if ($value instanceof Countable) {
        return 0 == count($value);
    }

    return false === $value || (empty($value) && '0' != $value);
}
