xmlStringCurrentChar(xmlParserCtxtPtr ctxt, const xmlChar * cur, int *len)
{
    if ((len == NULL) || (cur == NULL)) return(0);
    if ((ctxt == NULL) || (ctxt->charset == XML_CHAR_ENCODING_UTF8)) {
        /*
         * We are supposed to handle UTF8, check it's valid
         * From rfc2044: encoding of the Unicode values on UTF-8:
         *
         * UCS-4 range (hex.)           UTF-8 octet sequence (binary)
         * 0000 0000-0000 007F   0xxxxxxx
         * 0000 0080-0000 07FF   110xxxxx 10xxxxxx
         * 0000 0800-0000 FFFF   1110xxxx 10xxxxxx 10xxxxxx
         *
         * Check for the 0x110000 limit too
         */
        unsigned char c;
        unsigned int val;

        c = *cur;
        if (c & 0x80) {
            if ((cur[1] & 0xc0) != 0x80)
                goto encoding_error;
            if ((c & 0xe0) == 0xe0) {

                if ((cur[2] & 0xc0) != 0x80)
                    goto encoding_error;
                if ((c & 0xf0) == 0xf0) {
                    if (((c & 0xf8) != 0xf0) || ((cur[3] & 0xc0) != 0x80))
                        goto encoding_error;
                    /* 4-byte code */
                    *len = 4;
                    val = (cur[0] & 0x7) << 18;
                    val |= (cur[1] & 0x3f) << 12;
                    val |= (cur[2] & 0x3f) << 6;
                    val |= cur[3] & 0x3f;
                } else {
                    /* 3-byte code */
                    *len = 3;
                    val = (cur[0] & 0xf) << 12;
                    val |= (cur[1] & 0x3f) << 6;
                    val |= cur[2] & 0x3f;
                }
            } else {
                /* 2-byte code */
                *len = 2;
                val = (cur[0] & 0x1f) << 6;
                val |= cur[1] & 0x3f;
            }
            if (!IS_CHAR(val)) {
	        xmlErrEncodingInt(ctxt, XML_ERR_INVALID_CHAR,
				  "Char 0x%X out of allowed range\n", val);
            }
            return (val);
        } else {
            /* 1-byte code */
            *len = 1;
            return ((int) *cur);
        }
    }
    /*
     * Assume it's a fixed length encoding (1) with
     * a compatible encoding for the ASCII set, since
     * XML constructs only use < 128 chars
     */
    *len = 1;
    return ((int) *cur);
encoding_error:

    /*
     * An encoding problem may arise from a truncated input buffer
     * splitting a character in the middle. In that case do not raise
     * an error but return 0 to endicate an end of stream problem
     */
    if ((ctxt == NULL) || (ctxt->input == NULL) ||
        (ctxt->input->end - ctxt->input->cur < 4)) {
	*len = 0;
	return(0);
    }
    /*
     * If we detect an UTF8 error that probably mean that the
     * input encoding didn't get properly advertised in the
     * declaration header. Report the error and switch the encoding
     * to ISO-Latin-1 (if you don't like this policy, just declare the
     * encoding !)
     */
    {
        char buffer[150];

	snprintf(buffer, 149, "Bytes: 0x%02X 0x%02X 0x%02X 0x%02X\n",
			ctxt->input->cur[0], ctxt->input->cur[1],
			ctxt->input->cur[2], ctxt->input->cur[3]);
	__xmlErrEncoding(ctxt, XML_ERR_INVALID_CHAR,
		     "Input is not proper UTF-8, indicate encoding !\n%s",
		     BAD_CAST buffer, NULL);
    }
    *len = 1;
    return ((int) *cur);
}
Unknown