src/com/googlecode/lanterna/input/EscapeSequenceCharacterPattern.java

   1 package com.googlecode.lanterna.input;
   2
   3 import static com.googlecode.lanterna.input.KeyDecodingProfile.ESC_CODE;
   4
   5 import java.util.HashMap;
   6 import java.util.List;
   7 import java.util.Map;
   8
   9 /**
  10  * This implementation of CharacterPattern matches two similar patterns
  11  * of Escape sequences, that many terminals produce for special keys.<p>
  12  *
  13  * These sequences all start with Escape, followed by either an open bracket
  14  * or a capital letter O (these two are treated as equivalent).<p>
  15  *
  16  * Then follows a list of zero or up to two decimals separated by a
  17  * semicolon, and a non-digit last character.<p>
  18  *
  19  * If the last character is a tilde (~) then the first number defines
  20  * the key (through stdMap), otherwise the last character itself defines
  21  * the key (through finMap).<p>
  22  *
  23  * The second number, if provided by the terminal, specifies the modifier
  24  * state (shift,alt,ctrl). The value is 1 + sum(modifiers), where shift is 1,
  25  * alt is 2 and ctrl is 4.<p>
  26  *
  27  * The two maps stdMap and finMap can be customized in subclasses to add,
  28  * remove or replace keys - to support non-standard Terminals.<p>
  29  *
  30  * Examples: (on a gnome terminal)<br>
  31  * ArrowUp is "Esc [ A"; Alt-ArrowUp is "Esc [ 1 ; 3 A"<br>
  32  * both are handled by finMap mapping 'A' to ArrowUp <br><br>
  33  * F6 is "Esc [ 1 7 ~"; Ctrl-Shift-F6 is "Esc [ 1 7 ; 6 R"<br>
  34  * both are handled by stdMap mapping 17 to F6 <br><br>
  35  *
  36  * @author Andreas
  37  *
  38  */
  39 public class EscapeSequenceCharacterPattern implements CharacterPattern {
  40     // state machine used to match key sequence:
  41     private enum State {
  42         START, INTRO, NUM1, NUM2, DONE
  43     }
  44     // bit-values for modifier keys: only used internally
  45     public static final int SHIFT = 1, ALT = 2, CTRL = 4;
  46
  47     /**
  48      *  Map of recognized "standard pattern" sequences:<br>
  49      *   e.g.: 24 -&gt; F12 : "Esc [ <b>24</b> ~"
  50      */
  51     protected final Map<Integer, KeyType>   stdMap = new HashMap<Integer, KeyType>();
  52     /**
  53      *  Map of recognized "finish pattern" sequences:<br>
  54      *   e.g.: 'A' -&gt; ArrowUp : "Esc [ <b>A</b>"
  55      */
  56     protected final Map<Character, KeyType> finMap = new HashMap<Character, KeyType>();
  57     /**
  58      *  A flag to control, whether an Esc-prefix for an Esc-sequence is to be treated
  59      *  as Alt-pressed. Some Terminals (e.g. putty) report the Alt-modifier like that.<p>
  60      *  If the application is e.g. more interested in seeing separate Escape and plain
  61      *  Arrow keys, then it should replace this class by a subclass that sets this flag
  62      *  to false. (It might then also want to remove the CtrlAltAndCharacterPattern.)
  63      */
  64     protected boolean useEscEsc = true;
  65
  66     /**
  67      * Create an instance with a standard set of mappings.
  68      */
  69     public EscapeSequenceCharacterPattern() {
  70         finMap.put('A', KeyType.ArrowUp);
  71         finMap.put('B', KeyType.ArrowDown);
  72         finMap.put('C', KeyType.ArrowRight);
  73         finMap.put('D', KeyType.ArrowLeft);
  74         finMap.put('E', KeyType.Unknown); // gnome-terminal center key on numpad
  75         finMap.put('G', KeyType.Unknown); // putty center key on numpad
  76         finMap.put('H', KeyType.Home);
  77         finMap.put('F', KeyType.End);
  78         finMap.put('P', KeyType.F1);
  79         finMap.put('Q', KeyType.F2);
  80         finMap.put('R', KeyType.F3);
  81         finMap.put('S', KeyType.F4);
  82         finMap.put('Z', KeyType.ReverseTab);
  83
  84         stdMap.put(1,  KeyType.Home);
  85         stdMap.put(2,  KeyType.Insert);
  86         stdMap.put(3,  KeyType.Delete);
  87         stdMap.put(4,  KeyType.End);
  88         stdMap.put(5,  KeyType.PageUp);
  89         stdMap.put(6,  KeyType.PageDown);
  90         stdMap.put(11, KeyType.F1);
  91         stdMap.put(12, KeyType.F2);
  92         stdMap.put(13, KeyType.F3);
  93         stdMap.put(14, KeyType.F4);
  94         stdMap.put(15, KeyType.F5);
  95         stdMap.put(16, KeyType.F5);
  96         stdMap.put(17, KeyType.F6);
  97         stdMap.put(18, KeyType.F7);
  98         stdMap.put(19, KeyType.F8);
  99         stdMap.put(20, KeyType.F9);
 100         stdMap.put(21, KeyType.F10);
 101         stdMap.put(23, KeyType.F11);
 102         stdMap.put(24, KeyType.F12);
 103         stdMap.put(25, KeyType.F13);
 104         stdMap.put(26, KeyType.F14);
 105         stdMap.put(28, KeyType.F15);
 106         stdMap.put(29, KeyType.F16);
 107         stdMap.put(31, KeyType.F17);
 108         stdMap.put(32, KeyType.F18);
 109         stdMap.put(33, KeyType.F19);
 110     }
 111
 112     /**
 113      * combines a KeyType and modifiers into a KeyStroke.
 114      * Subclasses can override this for customization purposes.
 115      *
 116      * @param key the KeyType as determined by parsing the sequence.
 117      *   It will be null, if the pattern looked like a key sequence but wasn't
 118      *   identified.
 119      * @param mods the bitmask of the modifer keys pressed along with the key.
 120      * @return either null (to report mis-match), or a valid KeyStroke.
 121      */
 122     protected KeyStroke getKeyStroke(KeyType key, int mods) {
 123         boolean bShift = false, bCtrl = false, bAlt = false;
 124         if (key == null) { return null; } // alternative: key = KeyType.Unknown;
 125         if (mods >= 0) { // only use when non-negative!
 126             bShift = (mods & SHIFT) != 0;
 127             bAlt   = (mods & ALT)   != 0;
 128             bCtrl  = (mods & CTRL)  != 0;
 129         }
 130         return new KeyStroke( key , bCtrl, bAlt, bShift);
 131     }
 132
 133     /**
 134      * combines the raw parts of the sequence into a KeyStroke.
 135      * This method does not check the first char, but overrides may do so.
 136      *
 137      * @param first  the char following after Esc in the sequence (either [ or O)
 138      * @param num1   the first decimal, or 0 if not in the sequence
 139      * @param num2   the second decimal, or 0 if not in the sequence
 140      * @param last   the terminating char.
 141      * @param bEsc   whether an extra Escape-prefix was found.
 142      * @return either null (to report mis-match), or a valid KeyStroke.
 143      */
 144     protected KeyStroke getKeyStrokeRaw(char first,int num1,int num2,char last,boolean bEsc) {
 145         KeyType kt = null; boolean bPuttyCtrl = false;
 146         if (last == '~' && stdMap.containsKey(num1)) {
 147             kt = stdMap.get(num1);
 148         } else if (finMap.containsKey(last)) {
 149             kt = finMap.get(last);
 150             // Putty sends ^[OA for ctrl arrow-up, ^[[A for plain arrow-up:
 151             // but only for A-D -- other ^[O... sequences are just plain keys
 152             if (first == 'O' && last >= 'A' && last <= 'D') { bPuttyCtrl = true; }
 153             // if we ever stumble into "keypad-mode", then it will end up inverted.
 154         } else {
 155             kt = null; // unknown key.
 156         }
 157         int mods = num2 - 1;
 158         if (bEsc) {
 159             if (mods >= 0) { mods |= ALT; }
 160             else { mods = ALT; }
 161         }
 162         if (bPuttyCtrl) {
 163             if (mods >= 0) { mods |= CTRL; }
 164             else { mods = CTRL; }
 165         }
 166         return getKeyStroke( kt, mods );
 167     }
 168
 169     @Override
 170     public Matching match(List<Character> cur) {
 171         State state = State.START;
 172         int num1 = 0, num2 = 0;
 173         char first = '\0', last = '\0';
 174         boolean bEsc = false;
 175
 176         for (char ch : cur) {
 177             switch (state) {
 178             case START:
 179                 if (ch != ESC_CODE) {
 180                     return null; // nope
 181                 }
 182                 state = State.INTRO;
 183                 continue;
 184             case INTRO:
 185                 // Recognize a second Escape to mean "Alt is pressed".
 186                 // (at least putty sends it that way)
 187                 if (useEscEsc && ch == ESC_CODE && ! bEsc) {
 188                     bEsc = true; continue;
 189                 }
 190
 191                 // Key sequences supported by this class must
 192                 //    start either with Esc-[ or Esc-O
 193                 if (ch != '[' && ch != 'O') {
 194                     return null; // nope
 195                 }
 196                 first = ch; state = State.NUM1;
 197                 continue;
 198             case NUM1:
 199                 if (ch == ';') {
 200                     state = State.NUM2;
 201                 } else if (Character.isDigit(ch)) {
 202                     num1 = num1 * 10 + Character.digit(ch, 10);
 203                 } else {
 204                     last = ch; state = State.DONE;
 205                 }
 206                 continue;
 207             case NUM2:
 208                 if (Character.isDigit(ch)) {
 209                     num2 = num2 * 10 + Character.digit(ch, 10);
 210                 } else {
 211                     last = ch; state = State.DONE;
 212                 }
 213                 continue;
 214             case DONE: // once done, extra characters spoil it
 215                 return null; // nope
 216             }
 217         }
 218         if (state == State.DONE) {
 219             KeyStroke ks = getKeyStrokeRaw(first,num1,num2,last,bEsc);
 220             return ks != null ? new Matching( ks ) : null; // depends
 221         } else {
 222             return Matching.NOT_YET; // maybe later
 223         }
 224     }
 225 }