Method parseLength

java/org/apache/tomcat/util/buf/Asn1Parser.java:160–192

Parses an ASN.1 length field. @return the parsed length value

()

     * @return the parsed length value
     */
    public int parseLength() {
        int len = next();
        if (len > 127) {
            int bytes = len - 128;
            if (bytes > 4) {
                throw new IllegalArgumentException(sm.getString("asn1Parser.lengthInvalid", Integer.valueOf(-1),
                        Integer.valueOf(source.length - pos)));
            }
            len = 0;
            for (int i = 0; i < bytes; i++) {
                len = len << 8;
                len = len + next();
            }
            if (len < 0) {
                throw new IllegalArgumentException(sm.getString("asn1Parser.lengthInvalid", Integer.valueOf(-1),
                        Integer.valueOf(source.length - pos)));
            }
        }
        /*
         * If this is the first length parsed after a sequence has been added to the sequence nesting tracking mechanism
         * it must be the length of the sequence so update the entry to record the end position of the sequence. Note
         * that position recorded is actually the start of the first element after the sequence ends.
         */
        if (nestedSequenceEndPositions.peekLast() != null && nestedSequenceEndPositions.peekLast().intValue() == -1) {
            nestedSequenceEndPositions.pollLast();
            if (source.length - pos < len) {
                throw new IllegalArgumentException(sm.getString("asn1Parser.lengthInvalid", Integer.valueOf(-1),
                        Integer.valueOf(source.length - pos)));
            }
            nestedSequenceEndPositions.addLast(Integer.valueOf(pos + len));
        }
        return len;
    }


    /**