001/****************************************************************
002 * Licensed to the Apache Software Foundation (ASF) under one   *
003 * or more contributor license agreements.  See the NOTICE file *
004 * distributed with this work for additional information        *
005 * regarding copyright ownership.  The ASF licenses this file   *
006 * to you under the Apache License, Version 2.0 (the            *
007 * "License"); you may not use this file except in compliance   *
008 * with the License.  You may obtain a copy of the License at   *
009 *                                                              *
010 *   http://www.apache.org/licenses/LICENSE-2.0                 *
011 *                                                              *
012 * Unless required by applicable law or agreed to in writing,   *
013 * software distributed under the License is distributed on an  *
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
015 * KIND, either express or implied.  See the License for the    *
016 * specific language governing permissions and limitations      *
017 * under the License.                                           *
018 ****************************************************************/
019
020package org.apache.james.mime4j.stream;
021
022import java.util.BitSet;
023
024import org.apache.james.mime4j.MimeException;
025import org.apache.james.mime4j.io.MaxHeaderLengthLimitException;
026import org.apache.james.mime4j.util.ByteArrayBuffer;
027
028/**
029 * Default implementation of {@link FieldBuilder}.
030 *
031 */
032public class DefaultFieldBuilder implements FieldBuilder {
033
034    private static final BitSet FIELD_CHARS = new BitSet();
035
036    static {
037        for (int i = 0x21; i <= 0x39; i++) {
038            FIELD_CHARS.set(i);
039        }
040        for (int i = 0x3b; i <= 0x7e; i++) {
041            FIELD_CHARS.set(i);
042        }
043    }
044
045    private final ByteArrayBuffer buf;
046    private final int maxlen;
047
048    public DefaultFieldBuilder(int maxlen) {
049        this.buf = new ByteArrayBuffer(1024);
050        this.maxlen = maxlen;
051    }
052
053    public void reset() {
054        this.buf.clear();
055    }
056
057    public void append(final ByteArrayBuffer line) throws MaxHeaderLengthLimitException {
058        if (line == null) {
059            return;
060        }
061        int len = line.length();
062        if (this.maxlen > 0 && this.buf.length() + len >= this.maxlen) {
063            throw new MaxHeaderLengthLimitException("Maximum header length limit exceeded");
064        }
065        this.buf.append(line.buffer(), 0, line.length());
066    }
067
068    public RawField build() throws MimeException {
069        int len = this.buf.length();
070        if (len > 0) {
071            if (this.buf.byteAt(len - 1) == '\n') {
072                len --;
073            }
074            if (this.buf.byteAt(len - 1) == '\r') {
075                len --;
076            }
077        }
078        ByteArrayBuffer copy = new ByteArrayBuffer(this.buf.buffer(), len, false);
079        RawField field = RawFieldParser.DEFAULT.parseField(copy);
080        String name = field.getName();
081        for (int i = 0; i < name.length(); i++) {
082            char ch = name.charAt(i);
083            if (!FIELD_CHARS.get(ch)) {
084                throw new MimeException("MIME field name contains illegal characters: "
085                        + field.getName());
086            }
087        }
088        return field;
089    }
090
091    public ByteArrayBuffer getRaw() {
092        return this.buf;
093    }
094
095}