| 1 | /* |
| 2 | * This file is part of lanterna (http://code.google.com/p/lanterna/). |
| 3 | * |
| 4 | * lanterna is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU Lesser General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public License |
| 15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | * |
| 17 | * Copyright (C) 2010-2015 Martin |
| 18 | */ |
| 19 | package com.googlecode.lanterna.input; |
| 20 | |
| 21 | import com.googlecode.lanterna.input.CharacterPattern.Matching; |
| 22 | |
| 23 | import java.io.BufferedReader; |
| 24 | import java.io.IOException; |
| 25 | import java.io.Reader; |
| 26 | import java.util.*; |
| 27 | |
| 28 | /** |
| 29 | * Used to read the input stream character by character and generate {@code Key} objects to be put in the input queue. |
| 30 | * |
| 31 | * @author Martin, Andreas |
| 32 | */ |
| 33 | public class InputDecoder { |
| 34 | private final Reader source; |
| 35 | private final List<CharacterPattern> bytePatterns; |
| 36 | private final List<Character> currentMatching; |
| 37 | private boolean seenEOF; |
| 38 | private int timeoutUnits; |
| 39 | |
| 40 | /** |
| 41 | * Creates a new input decoder using a specified Reader as the source to read characters from |
| 42 | * @param source Reader to read characters from, will be wrapped by a BufferedReader |
| 43 | */ |
| 44 | public InputDecoder(final Reader source) { |
| 45 | this.source = new BufferedReader(source); |
| 46 | this.bytePatterns = new ArrayList<CharacterPattern>(); |
| 47 | this.currentMatching = new ArrayList<Character>(); |
| 48 | this.seenEOF = false; |
| 49 | this.timeoutUnits = 0; // default is no wait at all |
| 50 | } |
| 51 | |
| 52 | /** |
| 53 | * Adds another key decoding profile to this InputDecoder, which means all patterns from the profile will be used |
| 54 | * when decoding input. |
| 55 | * @param profile Profile to add |
| 56 | */ |
| 57 | public void addProfile(KeyDecodingProfile profile) { |
| 58 | for (CharacterPattern pattern : profile.getPatterns()) { |
| 59 | synchronized(bytePatterns) { |
| 60 | //If an equivalent pattern already exists, remove it first |
| 61 | bytePatterns.remove(pattern); |
| 62 | bytePatterns.add(pattern); |
| 63 | } |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Returns a collection of all patterns registered in this InputDecoder. |
| 69 | * @return Collection of patterns in the InputDecoder |
| 70 | */ |
| 71 | public synchronized Collection<CharacterPattern> getPatterns() { |
| 72 | synchronized(bytePatterns) { |
| 73 | return new ArrayList<CharacterPattern>(bytePatterns); |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Removes one pattern from the list of patterns in this InputDecoder |
| 79 | * @param pattern Pattern to remove |
| 80 | * @return {@code true} if the supplied pattern was found and was removed, otherwise {@code false} |
| 81 | */ |
| 82 | public boolean removePattern(CharacterPattern pattern) { |
| 83 | synchronized(bytePatterns) { |
| 84 | return bytePatterns.remove(pattern); |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | /** |
| 89 | * Sets the number of 1/4-second units for how long to try to get further input |
| 90 | * to complete an escape-sequence for a special Key. |
| 91 | * |
| 92 | * Negative numbers are mapped to 0 (no wait at all), and unreasonably high |
| 93 | * values are mapped to a maximum of 240 (1 minute). |
| 94 | */ |
| 95 | public void setTimeoutUnits(int units) { |
| 96 | timeoutUnits = (units < 0) ? 0 : |
| 97 | (units > 240) ? 240 : |
| 98 | units; |
| 99 | } |
| 100 | /** |
| 101 | * queries the current timeoutUnits value. One unit is 1/4 second. |
| 102 | * @return The timeout this InputDecoder will use when waiting for additional input, in units of 1/4 seconds |
| 103 | */ |
| 104 | public int getTimeoutUnits() { |
| 105 | return timeoutUnits; |
| 106 | } |
| 107 | |
| 108 | /** |
| 109 | * Reads and decodes the next key stroke from the input stream |
| 110 | * @return Key stroke read from the input stream, or {@code null} if none |
| 111 | * @throws IOException If there was an I/O error when reading from the input stream |
| 112 | */ |
| 113 | public synchronized KeyStroke getNextCharacter(boolean blockingIO) throws IOException { |
| 114 | |
| 115 | KeyStroke bestMatch = null; |
| 116 | int bestLen = 0; |
| 117 | int curLen = 0; |
| 118 | |
| 119 | while(true) { |
| 120 | |
| 121 | if ( curLen < currentMatching.size() ) { |
| 122 | // (re-)consume characters previously read: |
| 123 | curLen++; |
| 124 | } |
| 125 | else { |
| 126 | // If we already have a bestMatch but a chance for a longer match |
| 127 | // then we poll for the configured number of timeout units: |
| 128 | // It would be much better, if we could just read with a timeout, |
| 129 | // but lacking that, we wait 1/4s units and check for readiness. |
| 130 | if (bestMatch != null) { |
| 131 | int timeout = getTimeoutUnits(); |
| 132 | while (timeout > 0 && ! source.ready() ) { |
| 133 | try { |
| 134 | timeout--; Thread.sleep(250); |
| 135 | } catch (InterruptedException e) { timeout = 0; } |
| 136 | } |
| 137 | } |
| 138 | // if input is available, we can just read a char without waiting, |
| 139 | // otherwise, for readInput() with no bestMatch found yet, |
| 140 | // we have to wait blocking for more input: |
| 141 | if ( source.ready() || ( blockingIO && bestMatch == null ) ) { |
| 142 | int readChar = source.read(); |
| 143 | if (readChar == -1) { |
| 144 | seenEOF = true; |
| 145 | if(currentMatching.isEmpty()) { |
| 146 | return new KeyStroke(KeyType.EOF); |
| 147 | } |
| 148 | break; |
| 149 | } |
| 150 | currentMatching.add( (char)readChar ); |
| 151 | curLen++; |
| 152 | } else { // no more available input at this time. |
| 153 | // already found something: |
| 154 | if (bestMatch != null) { |
| 155 | break; // it's something... |
| 156 | } |
| 157 | // otherwise: no KeyStroke yet |
| 158 | return null; |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | List<Character> curSub = currentMatching.subList(0, curLen); |
| 163 | Matching matching = getBestMatch( curSub ); |
| 164 | |
| 165 | // fullMatch found... |
| 166 | if (matching.fullMatch != null) { |
| 167 | bestMatch = matching.fullMatch; |
| 168 | bestLen = curLen; |
| 169 | |
| 170 | if (! matching.partialMatch) { |
| 171 | // that match and no more |
| 172 | break; |
| 173 | } else { |
| 174 | // that match, but maybe more |
| 175 | continue; |
| 176 | } |
| 177 | } |
| 178 | // No match found yet, but there's still potential... |
| 179 | else if ( matching.partialMatch ) { |
| 180 | continue; |
| 181 | } |
| 182 | // no longer match possible at this point: |
| 183 | else { |
| 184 | if (bestMatch != null ) { |
| 185 | // there was already a previous full-match, use it: |
| 186 | break; |
| 187 | } else { // invalid input! |
| 188 | // remove the whole fail and re-try finding a KeyStroke... |
| 189 | curSub.clear(); // or just 1 char? currentMatching.remove(0); |
| 190 | curLen = 0; |
| 191 | continue; |
| 192 | } |
| 193 | } |
| 194 | } |
| 195 | |
| 196 | //Did we find anything? Otherwise return null |
| 197 | if(bestMatch == null) { |
| 198 | if(seenEOF) { |
| 199 | currentMatching.clear(); |
| 200 | return new KeyStroke(KeyType.EOF); |
| 201 | } |
| 202 | return null; |
| 203 | } |
| 204 | |
| 205 | List<Character> bestSub = currentMatching.subList(0, bestLen ); |
| 206 | bestSub.clear(); // remove matched characters from input |
| 207 | return bestMatch; |
| 208 | } |
| 209 | |
| 210 | private Matching getBestMatch(List<Character> characterSequence) { |
| 211 | boolean partialMatch = false; |
| 212 | KeyStroke bestMatch = null; |
| 213 | synchronized(bytePatterns) { |
| 214 | for(CharacterPattern pattern : bytePatterns) { |
| 215 | Matching res = pattern.match(characterSequence); |
| 216 | if (res != null) { |
| 217 | if (res.partialMatch) { partialMatch = true; } |
| 218 | if (res.fullMatch != null) { bestMatch = res.fullMatch; } |
| 219 | } |
| 220 | } |
| 221 | } |
| 222 | return new Matching(partialMatch, bestMatch); |
| 223 | } |
| 224 | } |