xmlParseEncodingDecl(xmlParserCtxtPtr ctxt) {
    xmlChar *encoding = NULL;

    SKIP_BLANKS;
    if (CMP8(CUR_PTR, 'e', 'n', 'c', 'o', 'd', 'i', 'n', 'g')) {
	SKIP(8);
	SKIP_BLANKS;
	if (RAW != '=') {
	    xmlFatalErr(ctxt, XML_ERR_EQUAL_REQUIRED, NULL);
	    return(NULL);
        }
	NEXT;
	SKIP_BLANKS;
	if (RAW == '"') {
	    NEXT;
	    encoding = xmlParseEncName(ctxt);
	    if (RAW != '"') {
		xmlFatalErr(ctxt, XML_ERR_STRING_NOT_CLOSED, NULL);
		xmlFree((xmlChar *) encoding);
		return(NULL);
	    } else
	        NEXT;
	} else if (RAW == '\''){
	    NEXT;
	    encoding = xmlParseEncName(ctxt);
	    if (RAW != '\'') {
		xmlFatalErr(ctxt, XML_ERR_STRING_NOT_CLOSED, NULL);
		xmlFree((xmlChar *) encoding);
		return(NULL);
	    } else
	        NEXT;
	} else {
	    xmlFatalErr(ctxt, XML_ERR_STRING_NOT_STARTED, NULL);
	}

        /*
         * Non standard parsing, allowing the user to ignore encoding
         */
        if (ctxt->options & XML_PARSE_IGNORE_ENC) {
	    xmlFree((xmlChar *) encoding);
            return(NULL);
	}

	/*
	 * UTF-16 encoding stwich has already taken place at this stage,
	 * more over the little-endian/big-endian selection is already done
	 */
        if ((encoding != NULL) &&
	    ((!xmlStrcasecmp(encoding, BAD_CAST "UTF-16")) ||
	     (!xmlStrcasecmp(encoding, BAD_CAST "UTF16")))) {
	    /*
	     * If no encoding was passed to the parser, that we are
	     * using UTF-16 and no decoder is present i.e. the
	     * document is apparently UTF-8 compatible, then raise an
	     * encoding mismatch fatal error
	     */
	    if ((ctxt->encoding == NULL) &&
	        (ctxt->input->buf != NULL) &&
	        (ctxt->input->buf->encoder == NULL)) {
		xmlFatalErrMsg(ctxt, XML_ERR_INVALID_ENCODING,
		  "Document labelled UTF-16 but has UTF-8 content\n");
	    }
	    if (ctxt->encoding != NULL)
		xmlFree((xmlChar *) ctxt->encoding);
	    ctxt->encoding = encoding;
	}
	/*
	 * UTF-8 encoding is handled natively
	 */
        else if ((encoding != NULL) &&
	    ((!xmlStrcasecmp(encoding, BAD_CAST "UTF-8")) ||
	     (!xmlStrcasecmp(encoding, BAD_CAST "UTF8")))) {
	    if (ctxt->encoding != NULL)
		xmlFree((xmlChar *) ctxt->encoding);
	    ctxt->encoding = encoding;
	}
	else if (encoding != NULL) {
	    xmlCharEncodingHandlerPtr handler;

	    if (ctxt->input->encoding != NULL)
		xmlFree((xmlChar *) ctxt->input->encoding);
	    ctxt->input->encoding = encoding;

            handler = xmlFindCharEncodingHandler((const char *) encoding);
	    if (handler != NULL) {
		if (xmlSwitchToEncoding(ctxt, handler) < 0) {
		    /* failed to convert */
		    ctxt->errNo = XML_ERR_UNSUPPORTED_ENCODING;
		    return(NULL);
		}
	    } else {
		xmlFatalErrMsgStr(ctxt, XML_ERR_UNSUPPORTED_ENCODING,
			"Unsupported encoding %s\n", encoding);
		return(NULL);
	    }
	}
    }
    return(encoding);
}
Unknown