PhpXmlRpc\Helper\XMLParser::guessEncoding()

Complexity

Conditions	11
Paths	14

Size

Total Lines	73
Code Lines	25

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	20
CRAP Score	11.5605

Importance

Changes	1
Bugs	0	Features	0

<?php
    public static function guessEncoding($httpHeader = '', $xmlChunk = '', $encodingPrefs = null)
    {
        // discussion: see http://www.yale.edu/pclt/encoding/
        // 1 - test if encoding is specified in HTTP HEADERS

        // Details:
        // LWS:           (\13\10)?( |\t)+
        // token:         (any char but excluded stuff)+
        // quoted string: " (any char but double quotes and control chars)* "
        // header:        Content-type = ...; charset=value(; ...)*
        //   where value is of type token, no LWS allowed between 'charset' and value
        // Note: we do not check for invalid chars in VALUE:
        //   this had better be done using pure ereg as below
        // Note 2: we might be removing whitespace/tabs that ought to be left in if
        //   the received charset is a quoted string. But nobody uses such charset names...

        /// @todo this test will pass if ANY header has charset specification, not only Content-Type. Fix it?
        $matches = array();
        if (preg_match('/;\s*charset\s*=([^;]+)/i', $httpHeader, $matches)) {
            return strtoupper(trim($matches[1], " \t\""));
        }

        // 2 - scan the first bytes of the data for a UTF-16 (or other) BOM pattern
        //     (source: http://www.w3.org/TR/2000/REC-xml-20001006)
        //     NOTE: actually, according to the spec, even if we find the BOM and determine
        //     an encoding, we should check if there is an encoding specified
        //     in the xml declaration, and verify if they match.
        /// @todo implement check as described above?
        /// @todo implement check for first bytes of string even without a BOM? (It sure looks harder than for cases WITH a BOM)
        if (preg_match('/^(\x00\x00\xFE\xFF|\xFF\xFE\x00\x00|\x00\x00\xFF\xFE|\xFE\xFF\x00\x00)/', $xmlChunk)) {
            return 'UCS-4';
        } elseif (preg_match('/^(\xFE\xFF|\xFF\xFE)/', $xmlChunk)) {
            return 'UTF-16';
        } elseif (preg_match('/^(\xEF\xBB\xBF)/', $xmlChunk)) {
            return 'UTF-8';
        }

        // 3 - test if encoding is specified in the xml declaration
        /// @todo this regexp will fail if $xmlChunk uses UTF-32/UCS-4, and most likely UTF-16/UCS-2 as well. In that
        ///       case we leave the guesswork up to mbstring - which seems to be able to detect it, starting with php 5.6.
        ///       For lower versions, we could attempt usage of mb_ereg...
        // Details:
        // SPACE:         (#x20 | #x9 | #xD | #xA)+ === [ \x9\xD\xA]+
        // EQ:            SPACE?=SPACE? === [ \x9\xD\xA]*=[ \x9\xD\xA]*
        if (preg_match('/^<\?xml\s+version\s*=\s*' . "((?:\"[a-zA-Z0-9_.:-]+\")|(?:'[a-zA-Z0-9_.:-]+'))" .
            '\s+encoding\s*=\s*' . "((?:\"[A-Za-z][A-Za-z0-9._-]*\")|(?:'[A-Za-z][A-Za-z0-9._-]*'))/",
            $xmlChunk, $matches)) {
            return strtoupper(substr($matches[2], 1, -1));
        }

        // 4 - if mbstring is available, let it do the guesswork
        if (function_exists('mb_detect_encoding')) {
            if ($encodingPrefs == null && PhpXmlRpc::$xmlrpc_detectencodings != null) {

It seems like you are loosely comparing $encodingPrefs of type null|string against null; this is ambiguous if the string can be empty. Consider using a strict comparison === instead.

                $encodingPrefs = PhpXmlRpc::$xmlrpc_detectencodings;
            }
            if ($encodingPrefs) {
                $enc = mb_detect_encoding($xmlChunk, $encodingPrefs);
            } else {
                $enc = mb_detect_encoding($xmlChunk);
            }
            // NB: mb_detect likes to call it ascii, xml parser likes to call it US_ASCII...
            // IANA also likes better US-ASCII, so go with it
            if ($enc == 'ASCII') {
                $enc = 'US-' . $enc;
            }

            return $enc;
        } else {
            // no encoding specified: as per HTTP1.1 assume it is iso-8859-1?
            // Both RFC 2616 (HTTP 1.1) and 1945 (HTTP 1.0) clearly state that for text/xxx content types
            // this should be the standard. And we should be getting text/xml as request and response.
            // BUT we have to be backward compatible with the lib, which always used UTF-8 as default...
            return PhpXmlRpc::$xmlrpc_defencoding;
        }