<?php
/**
 * WordPress implementation for PHP functions either missing from older PHP versions or not included by default.
 *
 * @package PHP
 * @access private
 */

// If gettext isn't available
if ( !function_exists('_') ) {
    function _($string) {
        return $string;
    }
}

/**
 * Returns whether PCRE/u (PCRE_UTF8 modifier) is available for use.
 *
 * @ignore
 * @since 4.2.2
 * @access private
 *
 * @staticvar string $utf8_pcre
 *
 * @param bool $set - Used for testing only
 *             null   : default - get PCRE/u capability
 *             false  : Used for testing - return false for future calls to this function
 *             'reset': Used for testing - restore default behavior of this function
 */
function _wp_can_use_pcre_u( $set = null ) {
    static $utf8_pcre = 'reset';

    if ( null !== $set ) {
        $utf8_pcre = $set;
    }

    if ( 'reset' === $utf8_pcre ) {
        $utf8_pcre = @preg_match( '/^./u', 'a' );
    }

    return $utf8_pcre;
}

if ( ! function_exists( 'mb_substr' ) ) :
    /**
     * Compat function to mimic mb_substr().
     *
     * @ignore
     * @since 3.2.0
     *
     * @see _mb_substr()
     *
     * @param string      $str      The string to extract the substring from.
     * @param int         $start    Position to being extraction from in `$str`.
     * @param int|null    $length   Optional. Maximum number of characters to extract from `$str`.
     *                              Default null.
     * @param string|null $encoding Optional. Character encoding to use. Default null.
     * @return string Extracted substring.
     */
    function mb_substr( $str, $start, $length = null, $encoding = null ) {
        return _mb_substr( $str, $start, $length, $encoding );
    }
endif;

/**
 * Internal compat function to mimic mb_substr().
 *
 * Only understands UTF-8 and 8bit.  All other character sets will be treated as 8bit.
 * For $encoding === UTF-8, the $str input is expected to be a valid UTF-8 byte sequence.
 * The behavior of this function for invalid inputs is undefined.
 *
 * @ignore
 * @since 3.2.0
 *
 * @param string      $str      The string to extract the substring from.
 * @param int         $start    Position to being extraction from in `$str`.
 * @param int|null    $length   Optional. Maximum number of characters to extract from `$str`.
 *                              Default null.
 * @param string|null $encoding Optional. Character encoding to use. Default null.
 * @return string Extracted substring.
 */
function _mb_substr( $str, $start, $length = null, $encoding = null ) {
    if ( null === $encoding ) {
        $encoding = get_option( 'blog_charset' );
    }

    /*
     * The solution below works only for UTF-8, so in case of a different
     * charset just use built-in substr().
     */
    if ( ! in_array( $encoding, array( 'utf8', 'utf-8', 'UTF8', 'UTF-8' ) ) ) {
        return is_null( $length ) ? substr( $str, $start ) : substr( $str, $start, $length );
    }

    if ( _wp_can_use_pcre_u() ) {
        // Use the regex unicode support to separate the UTF-8 characters into an array.
        preg_match_all( '/./us', $str, $match );
        $chars = is_null( $length ) ? array_slice( $match[0], $start ) : array_slice( $match[0], $start, $length );
        return implode( '', $chars );
    }

    $regex = '/(
          [\x00-\x7F]                  # single-byte sequences   0xxxxxxx
        | [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx
        | \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2
        | [\xE1-\xEC][\x80-\xBF]{2}
        | \xED[\x80-\x9F][\x80-\xBF]
        | [\xEE-\xEF][\x80-\xBF]{2}
        | \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3
        | [\xF1-\xF3][\x80-\xBF]{3}
        | \xF4[\x80-\x8F][\x80-\xBF]{2}
    )/x';

    // Start with 1 element instead of 0 since the first thing we do is pop.
    $chars = array( '' );
    do {
        // We had some string left over from the last round, but we counted it in that last round.
        array_pop( $chars );

        /*
         * Split by UTF-8 character, limit to 1000 characters (last array element will contain
         * the rest of the string).
         */
        $pieces = preg_split( $regex, $str, 1000, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY );

        $chars = array_merge( $chars, $pieces );

    // If there's anything left over, repeat the loop.
    } while ( count( $pieces ) > 1 && $str = array_pop( $pieces ) );

    return join( '', array_slice( $chars, $start, $length ) );
}

if ( ! function_exists( 'mb_strlen' ) ) :
    /**
     * Compat function to mimic mb_strlen().
     *
     * @ignore
     * @since 4.2.0
     *
     * @see _mb_strlen()
     *
     * @param string      $str      The string to retrieve the character length from.
     * @param string|null $encoding Optional. Character encoding to use. Default null.
     * @return int String length of `$str`.
     */
    function mb_strlen( $str, $encoding = null ) {
        return _mb_strlen( $str, $encoding );
    }
endif;

/**
 * Internal compat function to mimic mb_strlen().
 *
 * Only understands UTF-8 and 8bit.  All other character sets will be treated as 8bit.
 * For $encoding === UTF-8, the `$str` input is expected to be a valid UTF-8 byte
 * sequence. The behavior of this function for invalid inputs is undefined.
 *
 * @ignore
 * @since 4.2.0
 *
 * @param string      $str      The string to retrieve the character length from.
 * @param string|null $encoding Optional. Character encoding to use. Default null.
 * @return int String length of `$str`.
 */
function _mb_strlen( $str, $encoding = null ) {
    if ( null === $encoding ) {
        $encoding = get_option( 'blog_charset' );
    }

    /*
     * The solution below works only for UTF-8, so in case of a different charset
     * just use built-in strlen().
     */
    if ( ! in_array( $encoding, array( 'utf8', 'utf-8', 'UTF8', 'UTF-8' ) ) ) {
        return strlen( $str );
    }

    if ( _wp_can_use_pcre_u() ) {
        // Use the regex unicode support to separate the UTF-8 characters into an array.
        preg_match_all( '/./us', $str, $match );
        return count( $match[0] );
    }

    $regex = '/(?:
          [\x00-\x7F]                  # single-byte sequences   0xxxxxxx
        | [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx
        | \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2
        | [\xE1-\xEC][\x80-\xBF]{2}
        | \xED[\x80-\x9F][\x80-\xBF]
        | [\xEE-\xEF][\x80-\xBF]{2}
        | \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3
        | [\xF1-\xF3][\x80-\xBF]{3}
        | \xF4[\x80-\x8F][\x80-\xBF]{2}
    )/x';

    // Start at 1 instead of 0 since the first thing we do is decrement.
    $count = 1;
    do {
        // We had some string left over from the last round, but we counted it in that last round.
        $count--;

        /*
         * Split by UTF-8 character, limit to 1000 characters (last array element will contain
         * the rest of the string).
         */
        $pieces = preg_split( $regex, $str, 1000 );

        // Increment.
        $count += count( $pieces );

    // If there's anything left over, repeat the loop.
    } while ( $str = array_pop( $pieces ) );

    // Fencepost: preg_split() always returns one extra item in the array.
    return --$count;
}

if ( !function_exists('hash_hmac') ):
/**
 * Compat function to mimic hash_hmac().
 *
 * @ignore
 * @since 3.2.0
 *
 * @see _hash_hmac()
 *
 * @param string $algo       Hash algorithm. Accepts 'md5' or 'sha1'.
 * @param string $data       Data to be hashed.
 * @param string $key        Secret key to use for generating the hash.
 * @param bool   $raw_output Optional. Whether to output raw binary data (true),
 *                           or lowercase hexits (false). Default false.
 * @return string|false The hash in output determined by `$raw_output`. False if `$algo`
 *                      is unknown or invalid.
 */
function hash_hmac($algo, $data, $key, $raw_output = false) {
    return _hash_hmac($algo, $data, $key, $raw_output);
}
endif;

/**
 * Internal compat function to mimic hash_hmac().
 *
 * @ignore
 * @since 3.2.0
 *
 * @param string $algo       Hash algorithm. Accepts 'md5' or 'sha1'.
 * @param string $data       Data to be hashed.
 * @param string $key        Secret key to use for generating the hash.
 * @param bool   $raw_output Optional. Whether to output raw binary data (true),
 *                           or lowercase hexits (false). Default false.
 * @return string|false The hash in output determined by `$raw_output`. False if `$algo`
 *                      is unknown or invalid.
 */
function _hash_hmac($algo, $data, $key, $raw_output = false) {
    $packs = array('md5' => 'H32', 'sha1' => 'H40');

    if ( !isset($packs[$algo]) )
        return false;

    $pack = $packs[$algo];

    if (strlen($key) > 64)
        $key = pack($pack, $algo($key));

    $key = str_pad($key, 64, chr(0));

    $ipad = (substr($key, 0, 64) ^ str_repeat(chr(0x36), 64));
    $opad = (substr($key, 0, 64) ^ str_repeat(chr(0x5C), 64));

    $hmac = $algo($opad . pack($pack, $algo($ipad . $data)));

    if ( $raw_output )
        return pack( $pack, $hmac );
    return $hmac;
}

if ( !function_exists('json_encode') ) {
    function json_encode( $string ) {
        global $wp_json;

        if ( ! ( $wp_json instanceof Services_JSON ) ) {
            require_once( ABSPATH . WPINC . '/class-json.php' );
            $wp_json = new Services_JSON();
        }

        return $wp_json->encodeUnsafe( $string );
    }
}

if ( !function_exists('json_decode') ) {
    /**
     * @global Services_JSON $wp_json
     * @param string $string
     * @param bool   $assoc_array
     * @return object|array
     */
    function json_decode( $string, $assoc_array = false ) {
        global $wp_json;

        if ( ! ($wp_json instanceof Services_JSON ) ) {
            require_once( ABSPATH . WPINC . '/class-json.php' );
            $wp_json = new Services_JSON();
        }

        $res = $wp_json->decode( $string );
        if ( $assoc_array )
            $res = _json_decode_object_helper( $res );
        return $res;
    }

    /**
     * @param object $data
     * @return array
     */
    function _json_decode_object_helper($data) {
        if ( is_object($data) )
            $data = get_object_vars($data);
        return is_array($data) ? array_map(__FUNCTION__, $data) : $data;
    }
}

if ( ! function_exists( 'hash_equals' ) ) :
/**
 * Timing attack safe string comparison
 *
 * Compares two strings using the same time whether they're equal or not.
 *
 * This function was added in PHP 5.6.
 *
 * Note: It can leak the length of a string when arguments of differing length are supplied.
 *
 * @since 3.9.2
 *
 * @param string $a Expected string.
 * @param string $b Actual, user supplied, string.
 * @return bool Whether strings are equal.
 */
function hash_equals( $a, $b ) {
    $a_length = strlen( $a );
    if ( $a_length !== strlen( $b ) ) {
        return false;
    }
    $result = 0;

    // Do not attempt to "optimize" this.
    for ( $i = 0; $i < $a_length; $i++ ) {
        $result |= ord( $a[ $i ] ) ^ ord( $b[ $i ] );
    }

    return $result === 0;
}
endif;

// JSON_PRETTY_PRINT was introduced in PHP 5.4
// Defined here to prevent a notice when using it with wp_json_encode()
if ( ! defined( 'JSON_PRETTY_PRINT' ) ) {
    define( 'JSON_PRETTY_PRINT', 128 );
}

if ( ! function_exists( 'json_last_error_msg' ) ) :
    /**
     * Retrieves the error string of the last json_encode() or json_decode() call.
     *
     * @since 4.4.0
     *
     * @internal This is a compatibility function for PHP <5.5
     *
     * @return bool|string Returns the error message on success, "No Error" if no error has occurred,
     *                     or false on failure.
     */
    function json_last_error_msg() {
        // See https://core.trac.wordpress.org/ticket/27799.
        if ( ! function_exists( 'json_last_error' ) ) {
            return false;
        }

        $last_error_code = json_last_error();

        // Just in case JSON_ERROR_NONE is not defined.
        $error_code_none = defined( 'JSON_ERROR_NONE' ) ? JSON_ERROR_NONE : 0;

        switch ( true ) {
            case $last_error_code === $error_code_none:
                return 'No error';

            case defined( 'JSON_ERROR_DEPTH' ) && JSON_ERROR_DEPTH === $last_error_code:
                return 'Maximum stack depth exceeded';

            case defined( 'JSON_ERROR_STATE_MISMATCH' ) && JSON_ERROR_STATE_MISMATCH === $last_error_code:
                return 'State mismatch (invalid or malformed JSON)';

            case defined( 'JSON_ERROR_CTRL_CHAR' ) && JSON_ERROR_CTRL_CHAR === $last_error_code:
                return 'Control character error, possibly incorrectly encoded';

            case defined( 'JSON_ERROR_SYNTAX' ) && JSON_ERROR_SYNTAX === $last_error_code:
                return 'Syntax error';

            case defined( 'JSON_ERROR_UTF8' ) && JSON_ERROR_UTF8 === $last_error_code:
                return 'Malformed UTF-8 characters, possibly incorrectly encoded';

            case defined( 'JSON_ERROR_RECURSION' ) && JSON_ERROR_RECURSION === $last_error_code:
                return 'Recursion detected';

            case defined( 'JSON_ERROR_INF_OR_NAN' ) && JSON_ERROR_INF_OR_NAN === $last_error_code:
                return 'Inf and NaN cannot be JSON encoded';

            case defined( 'JSON_ERROR_UNSUPPORTED_TYPE' ) && JSON_ERROR_UNSUPPORTED_TYPE === $last_error_code:
                return 'Type is not supported';

            default:
                return 'An unknown error occurred';
        }
    }
endif;

if ( ! interface_exists( 'JsonSerializable' ) ) {
    define( 'WP_JSON_SERIALIZE_COMPATIBLE', true );
    /**
     * JsonSerializable interface.
     *
     * Compatibility shim for PHP <5.4
     *
     * @link https://secure.php.net/jsonserializable
     *
     * @since 4.4.0
     */
    interface JsonSerializable {
        public function jsonSerialize();
    }
}

// random_int was introduced in PHP 7.0
if ( ! function_exists( 'random_int' ) ) {
    require COMMAND_ABSPATH . WPINC . '/random_compat/random.php';
}

if ( ! function_exists( 'array_replace_recursive' ) ) :
    /**
     * PHP-agnostic version of {@link array_replace_recursive()}.
     *
     * The array_replace_recursive() function is a PHP 5.3 function. WordPress
     * currently supports down to PHP 5.2, so this method is a workaround
     * for PHP 5.2.
     *
     * Note: array_replace_recursive() supports infinite arguments, but for our use-
     * case, we only need to support two arguments.
     *
     * Subject to removal once WordPress makes PHP 5.3.0 the minimum requirement.
     *
     * @since 4.5.3
     *
     * @see https://secure.php.net/manual/en/function.array-replace-recursive.php#109390
     *
     * @param  array $base         Array with keys needing to be replaced.
     * @param  array $replacements Array with the replaced keys.
     *
     * @return array
     */
    function array_replace_recursive( $base = array(), $replacements = array() ) {
        foreach ( array_slice( func_get_args(), 1 ) as $replacements ) {
            $bref_stack = array( &$base );
            $head_stack = array( $replacements );

            do {
                end( $bref_stack );

                $bref = &$bref_stack[ key( $bref_stack ) ];
                $head = array_pop( $head_stack );

                unset( $bref_stack[ key( $bref_stack ) ] );

                foreach ( array_keys( $head ) as $key ) {
                    if ( isset( $key, $bref ) &&
                         isset( $bref[ $key ] ) && is_array( $bref[ $key ] ) &&
                         isset( $head[ $key ] ) && is_array( $head[ $key ] )
                    ) {
                        $bref_stack[] = &$bref[ $key ];
                        $head_stack[] = $head[ $key ];
                    } else {
                        $bref[ $key ] = $head[ $key ];
                    }
                }
            } while ( count( $head_stack ) );
        }

        return $base;
    }
endif;