1 /*
   2  * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.nio;
  27 
  28 import java.util.Objects;
  29 
  30 // ## If the sequence is a string, use reflection to share its array
  31 
  32 class StringCharBuffer                                  // package-private
  33     extends CharBuffer
  34 {
  35     CharSequence str;
  36 
  37     StringCharBuffer(CharSequence s, int start, int end) { // package-private
  38         super(-1, start, end, s.length(), null);
  39         int n = s.length();
  40         Objects.checkFromToIndex(start, end, n);
  41         str = s;
  42         this.isReadOnly = true;
  43     }
  44 
  45     public CharBuffer slice() {
  46         return new StringCharBuffer(str,
  47                                     -1,
  48                                     0,
  49                                     this.remaining(),
  50                                     this.remaining(),
  51                                     offset + this.position());
  52     }
  53 
  54     @Override
  55     public CharBuffer slice(int index, int length) {
  56         Objects.checkFromIndexSize(index, length, limit());
  57         return new StringCharBuffer(str,
  58                                     -1,
  59                                     0,
  60                                     length,
  61                                     length,
  62                                     offset + index);
  63     }
  64 
  65     private StringCharBuffer(CharSequence s,
  66                              int mark,
  67                              int pos,
  68                              int limit,
  69                              int cap,
  70                              int offset) {
  71         super(mark, pos, limit, cap, null, offset, null);
  72         str = s;
  73         this.isReadOnly = true;
  74     }
  75 
  76     public CharBuffer duplicate() {
  77         return new StringCharBuffer(str, markValue(),
  78                                     position(), limit(), capacity(), offset);
  79     }
  80 
  81     public CharBuffer asReadOnlyBuffer() {
  82         return duplicate();
  83     }
  84 
  85     public final char get() {
  86         return str.charAt(nextGetIndex() + offset);
  87     }
  88 
  89     public final char get(int index) {
  90         return str.charAt(checkIndex(index) + offset);
  91     }
  92 
  93     char getUnchecked(int index) {
  94         return str.charAt(index + offset);
  95     }
  96 
  97     // ## Override bulk get methods for better performance
  98 
  99     public final CharBuffer put(char c) {
 100         throw new ReadOnlyBufferException();
 101     }
 102 
 103     public final CharBuffer put(int index, char c) {
 104         throw new ReadOnlyBufferException();
 105     }
 106 
 107     public final CharBuffer compact() {
 108         throw new ReadOnlyBufferException();
 109     }
 110 
 111     public final boolean isReadOnly() {
 112         return true;
 113     }
 114 
 115     final String toString(int start, int end) {
 116         return str.subSequence(start + offset, end + offset).toString();
 117     }
 118 
 119     public final CharBuffer subSequence(int start, int end) {
 120         try {
 121             int pos = position();
 122             return new StringCharBuffer(str,
 123                                         -1,
 124                                         pos + checkIndex(start, pos),
 125                                         pos + checkIndex(end, pos),
 126                                         capacity(),
 127                                         offset);
 128         } catch (IllegalArgumentException x) {
 129             throw new IndexOutOfBoundsException();
 130         }
 131     }
 132 
 133     public boolean isDirect() {
 134         return false;
 135     }
 136 
 137     public ByteOrder order() {
 138         return ByteOrder.nativeOrder();
 139     }
 140 
 141     ByteOrder charRegionOrder() {
 142         return null;
 143     }
 144 
 145     public boolean equals(Object ob) {
 146         if (this == ob)
 147             return true;
 148         if (!(ob instanceof CharBuffer))
 149             return false;
 150         CharBuffer that = (CharBuffer)ob;
 151         if (this.remaining() != that.remaining())
 152             return false;
 153         return BufferMismatch.mismatch(this, this.position(),
 154                                        that, that.position(),
 155                                        this.remaining()) < 0;
 156     }
 157 
 158     public int compareTo(CharBuffer that) {
 159         int i = BufferMismatch.mismatch(this, this.position(),
 160                                         that, that.position(),
 161                                         Math.min(this.remaining(), that.remaining()));
 162         if (i >= 0) {
 163             return Character.compare(this.get(this.position() + i), that.get(that.position() + i));
 164         }
 165         return this.remaining() - that.remaining();
 166     }
 167 }