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      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 
     17 package com.example.android.apis.os;
     18 
     19 /** Class that implements the text to morse code coversion */
     20 class MorseCodeConverter {
     21     private static final long SPEED_BASE = 100;
     22     static final long DOT = SPEED_BASE;
     23     static final long DASH = SPEED_BASE * 3;
     24     static final long GAP = SPEED_BASE;
     25     static final long LETTER_GAP = SPEED_BASE * 3;
     26     static final long WORD_GAP = SPEED_BASE * 7;
     27 
     28     /** The characters from 'A' to 'Z' */
     29     private static final long[][] LETTERS = new long[][] {
     30         /* A */ new long[] { DOT, GAP, DASH },
     31         /* B */ new long[] { DASH, GAP, DOT, GAP, DOT, GAP, DOT },
     32         /* C */ new long[] { DASH, GAP, DOT, GAP, DASH, GAP, DOT },
     33         /* D */ new long[] { DASH, GAP, DOT, GAP, DOT },
     34         /* E */ new long[] { DOT },
     35         /* F */ new long[] { DOT, GAP, DOT, GAP, DASH, GAP, DOT },
     36         /* G */ new long[] { DASH, GAP, DASH, GAP, DOT },
     37         /* H */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DOT },
     38         /* I */ new long[] { DOT, GAP, DOT },
     39         /* J */ new long[] { DOT, GAP, DASH, GAP, DASH, GAP, DASH },
     40         /* K */ new long[] { DASH, GAP, DOT, GAP, DASH },
     41         /* L */ new long[] { DOT, GAP, DASH, GAP, DOT, GAP, DOT },
     42         /* M */ new long[] { DASH, GAP, DASH },
     43         /* N */ new long[] { DASH, GAP, DOT },
     44         /* O */ new long[] { DASH, GAP, DASH, GAP, DASH },
     45         /* P */ new long[] { DOT, GAP, DASH, GAP, DASH, GAP, DOT },
     46         /* Q */ new long[] { DASH, GAP, DASH, GAP, DOT, GAP, DASH },
     47         /* R */ new long[] { DOT, GAP, DASH, GAP, DOT },
     48         /* S */ new long[] { DOT, GAP, DOT, GAP, DOT },
     49         /* T */ new long[] { DASH },
     50         /* U */ new long[] { DOT, GAP, DOT, GAP, DASH },
     51         /* V */ new long[] { DOT, GAP, DOT, GAP, DASH },
     52         /* W */ new long[] { DOT, GAP, DASH, GAP, DASH },
     53         /* X */ new long[] { DASH, GAP, DOT, GAP, DOT, GAP, DASH },
     54         /* Y */ new long[] { DASH, GAP, DOT, GAP, DASH, GAP, DASH },
     55         /* Z */ new long[] { DASH, GAP, DASH, GAP, DOT, GAP, DOT },
     56     };
     57 
     58     /** The characters from '0' to '9' */
     59     private static final long[][] NUMBERS = new long[][] {
     60         /* 0 */ new long[] { DASH, GAP, DASH, GAP, DASH, GAP, DASH, GAP, DASH },
     61         /* 1 */ new long[] { DOT, GAP, DASH, GAP, DASH, GAP, DASH, GAP, DASH },
     62         /* 2 */ new long[] { DOT, GAP, DOT, GAP, DASH, GAP, DASH, GAP, DASH },
     63         /* 3 */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DASH, GAP, DASH },
     64         /* 4 */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DOT, GAP, DASH },
     65         /* 5 */ new long[] { DOT, GAP, DOT, GAP, DOT, GAP, DOT, GAP, DOT },
     66         /* 6 */ new long[] { DASH, GAP, DOT, GAP, DOT, GAP, DOT, GAP, DOT },
     67         /* 7 */ new long[] { DASH, GAP, DASH, GAP, DOT, GAP, DOT, GAP, DOT },
     68         /* 8 */ new long[] { DASH, GAP, DASH, GAP, DASH, GAP, DOT, GAP, DOT },
     69         /* 9 */ new long[] { DASH, GAP, DASH, GAP, DASH, GAP, DASH, GAP, DOT },
     70     };
     71 
     72     private static final long[] ERROR_GAP = new long[] { GAP };
     73 
     74     /** Return the pattern data for a given character */
     75     static long[] pattern(char c) {
     76         if (c >= 'A' && c <= 'Z') {
     77             return LETTERS[c - 'A'];
     78         }
     79         if (c >= 'a' && c <= 'z') {
     80             return LETTERS[c - 'a'];
     81         }
     82         else if (c >= '0' && c <= '9') {
     83             return NUMBERS[c - '0'];
     84         }
     85         else {
     86             return ERROR_GAP;
     87         }
     88     }
     89 
     90     static long[] pattern(String str) {
     91         boolean lastWasWhitespace;
     92         int strlen = str.length();
     93 
     94         // Calculate how long our array needs to be.
     95         int len = 1;
     96         lastWasWhitespace = true;
     97         for (int i=0; i<strlen; i++) {
     98             char c = str.charAt(i);
     99             if (Character.isWhitespace(c)) {
    100                 if (!lastWasWhitespace) {
    101                     len++;
    102                     lastWasWhitespace = true;
    103                 }
    104             } else {
    105                 if (!lastWasWhitespace) {
    106                     len++;
    107                 }
    108                 lastWasWhitespace = false;
    109                 len += pattern(c).length;
    110             }
    111         }
    112 
    113         // Generate the pattern array.  Note that we put an extra element of 0
    114         // in at the beginning, because the pattern always starts with the pause,
    115         // not with the vibration.
    116         long[] result = new long[len+1];
    117         result[0] = 0;
    118         int pos = 1;
    119         lastWasWhitespace = true;
    120         for (int i=0; i<strlen; i++) {
    121             char c = str.charAt(i);
    122             if (Character.isWhitespace(c)) {
    123                 if (!lastWasWhitespace) {
    124                     result[pos] = WORD_GAP;
    125                     pos++;
    126                     lastWasWhitespace = true;
    127                 }
    128             } else {
    129                 if (!lastWasWhitespace) {
    130                     result[pos] = LETTER_GAP;
    131                     pos++;
    132                 }
    133                 lastWasWhitespace = false;
    134                 long[] letter = pattern(c);
    135                 System.arraycopy(letter, 0, result, pos, letter.length);
    136                 pos += letter.length;
    137             }
    138         }
    139         return result;
    140     }
    141 }
    142