1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.common;
18
19import android.text.InputFilter;
20import android.text.Spanned;
21import android.text.SpannableStringBuilder;
22
23/**
24 * Implements special address cleanup rules:
25 * The first space key entry following an "@" symbol that is followed by any combination
26 * of letters and symbols, including one+ dots and zero commas, should insert an extra
27 * comma (followed by the space).
28 *
29 * @hide
30 */
31public class Rfc822InputFilter implements InputFilter {
32
33    public CharSequence filter(CharSequence source, int start, int end, Spanned dest,
34        int dstart, int dend) {
35
36        // quick check - did they enter a single space?
37        if (end-start != 1 || source.charAt(start) != ' ') {
38            return null;
39        }
40
41        // determine if the characters before the new space fit the pattern
42        // follow backwards and see if we find a comma, dot, or @
43        int scanBack = dstart;
44        boolean dotFound = false;
45        while (scanBack > 0) {
46            char c = dest.charAt(--scanBack);
47            switch (c) {
48                case '.':
49                    dotFound = true;    // one or more dots are req'd
50                    break;
51                case ',':
52                    return null;
53                case '@':
54                    if (!dotFound) {
55                        return null;
56                    }
57                    // we have found a comma-insert case.  now just do it
58                    // in the least expensive way we can.
59                    if (source instanceof Spanned) {
60                        SpannableStringBuilder sb = new SpannableStringBuilder(",");
61                        sb.append(source);
62                        return sb;
63                    } else {
64                        return ", ";
65                    }
66                default:
67                    // just keep going
68            }
69        }
70
71        // no termination cases were found, so don't edit the input
72        return null;
73    }
74}
75