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      1 /*
      2  * Copyright (C) 2006 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.android.internal.telephony;
     18 
     19 /**
     20  * {@hide}
     21  */
     22 public class ATResponseParser
     23 {
     24     /*************************** Instance Variables **************************/
     25 
     26     private String line;
     27     private int next = 0;
     28     private int tokStart, tokEnd;
     29 
     30     /***************************** Class Methods *****************************/
     31 
     32     public
     33     ATResponseParser (String line)
     34     {
     35         this.line = line;
     36     }
     37 
     38     public boolean
     39     nextBoolean()
     40     {
     41         // "\s*(\d)(,|$)"
     42         // \d is '0' or '1'
     43 
     44         nextTok();
     45 
     46         if (tokEnd - tokStart > 1) {
     47             throw new ATParseEx();
     48         }
     49         char c = line.charAt(tokStart);
     50 
     51         if (c == '0') return false;
     52         if (c ==  '1') return true;
     53         throw new ATParseEx();
     54     }
     55 
     56 
     57     /** positive int only */
     58     public int
     59     nextInt()
     60     {
     61         // "\s*(\d+)(,|$)"
     62         int ret = 0;
     63 
     64         nextTok();
     65 
     66         for (int i = tokStart ; i < tokEnd ; i++) {
     67             char c = line.charAt(i);
     68 
     69             // Yes, ASCII decimal digits only
     70             if (c < '0' || c > '9') {
     71                 throw new ATParseEx();
     72             }
     73 
     74             ret *= 10;
     75             ret += c - '0';
     76         }
     77 
     78         return ret;
     79     }
     80 
     81     public String
     82     nextString()
     83     {
     84         nextTok();
     85 
     86         return line.substring(tokStart, tokEnd);
     87     }
     88 
     89     public boolean
     90     hasMore()
     91     {
     92         return next < line.length();
     93     }
     94 
     95     private void
     96     nextTok()
     97     {
     98         int len = line.length();
     99 
    100         if (next == 0) {
    101             skipPrefix();
    102         }
    103 
    104         if (next >= len) {
    105             throw new ATParseEx();
    106         }
    107 
    108         try {
    109             // \s*("([^"]*)"|(.*)\s*)(,|$)
    110 
    111             char c = line.charAt(next++);
    112             boolean hasQuote = false;
    113 
    114             c = skipWhiteSpace(c);
    115 
    116             if (c == '"') {
    117                 if (next >= len) {
    118                     throw new ATParseEx();
    119                 }
    120                 c = line.charAt(next++);
    121                 tokStart = next - 1;
    122                 while (c != '"' && next < len) {
    123                     c = line.charAt(next++);
    124                 }
    125                 if (c != '"') {
    126                     throw new ATParseEx();
    127                 }
    128                 tokEnd = next - 1;
    129                 if (next < len && line.charAt(next++) != ',') {
    130                     throw new ATParseEx();
    131                 }
    132             } else {
    133                 tokStart = next - 1;
    134                 tokEnd = tokStart;
    135                 while (c != ',') {
    136                     if (!Character.isWhitespace(c)) {
    137                         tokEnd = next;
    138                     }
    139                     if (next == len) {
    140                         break;
    141                     }
    142                     c = line.charAt(next++);
    143                 }
    144             }
    145         } catch (StringIndexOutOfBoundsException ex) {
    146             throw new ATParseEx();
    147         }
    148     }
    149 
    150 
    151     /** Throws ATParseEx if whitespace extends to the end of string */
    152     private char
    153     skipWhiteSpace (char c)
    154     {
    155         int len;
    156         len = line.length();
    157         while (next < len && Character.isWhitespace(c)) {
    158             c = line.charAt(next++);
    159         }
    160 
    161         if (Character.isWhitespace(c)) {
    162             throw new ATParseEx();
    163         }
    164         return c;
    165     }
    166 
    167 
    168     private void
    169     skipPrefix()
    170     {
    171         // consume "^[^:]:"
    172 
    173         next = 0;
    174         int s = line.length();
    175         while (next < s){
    176             char c = line.charAt(next++);
    177 
    178             if (c == ':') {
    179                 return;
    180             }
    181         }
    182 
    183         throw new ATParseEx("missing prefix");
    184     }
    185 
    186 }
    187