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      1 /*
      2  * Copyright (C) 2011 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.dx.io.instructions;
     18 
     19 import java.io.EOFException;
     20 
     21 /**
     22  * Base implementation of {@link CodeCursor}.
     23  */
     24 public abstract class BaseCodeCursor implements CodeCursor {
     25     /** base address map */
     26     private final AddressMap baseAddressMap;
     27 
     28     /** next index within {@link #array} to read from or write to */
     29     private int cursor;
     30 
     31     /**
     32      * Constructs an instance.
     33      */
     34     public BaseCodeCursor() {
     35         this.baseAddressMap = new AddressMap();
     36         this.cursor = 0;
     37     }
     38 
     39     /** @inheritDoc */
     40     public final int cursor() {
     41         return cursor;
     42     }
     43 
     44     /** @inheritDoc */
     45     public final int baseAddressForCursor() {
     46         int mapped = baseAddressMap.get(cursor);
     47         return (mapped >= 0) ? mapped : cursor;
     48     }
     49 
     50     /** @inheritDoc */
     51     public final void setBaseAddress(int targetAddress, int baseAddress) {
     52         baseAddressMap.put(targetAddress, baseAddress);
     53     }
     54 
     55     /**
     56      * Advance the cursor by the indicated amount.
     57      */
     58     protected final void advance(int amount) {
     59         cursor += amount;
     60     }
     61 }
     62