1 /*
   2  * Copyright (c) 1999, 2015, 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 com.sun.tools.javac.util;
  27 
  28 import com.sun.tools.javac.util.DefinedBy.Api;
  29 
  30 /** An abstraction for internal compiler strings. They are stored in
  31  *  Utf8 format. Names are stored in a Name.Table, and are unique within
  32  *  that table.
  33  *
  34  *  <p><b>This is NOT part of any supported API.
  35  *  If you write code that depends on this, you do so at your own risk.
  36  *  This code and its internal interfaces are subject to change or
  37  *  deletion without notice.</b>
  38  */
  39 public abstract class Name implements javax.lang.model.element.Name {
  40 
  41     public final Table table;
  42 
  43     protected Name(Table table) {
  44         this.table = table;
  45     }
  46 
  47     /**
  48      * {@inheritDoc}
  49      */
  50     @DefinedBy(Api.LANGUAGE_MODEL)
  51     public boolean contentEquals(CharSequence cs) {
  52         return toString().equals(cs.toString());
  53     }
  54 
  55     /**
  56      * {@inheritDoc}
  57      */
  58     public int length() {
  59         return toString().length();
  60     }
  61 
  62     /**
  63      * {@inheritDoc}
  64      */
  65     public char charAt(int index) {
  66         return toString().charAt(index);
  67     }
  68 
  69     /**
  70      * {@inheritDoc}
  71      */
  72     public CharSequence subSequence(int start, int end) {
  73         return toString().subSequence(start, end);
  74     }
  75 
  76     /** Return the concatenation of this name and name `n'.
  77      */
  78     public Name append(Name n) {
  79         int len = getByteLength();
  80         byte[] bs = new byte[len + n.getByteLength()];
  81         getBytes(bs, 0);
  82         n.getBytes(bs, len);
  83         return table.fromUtf(bs, 0, bs.length);
  84     }
  85 
  86     /** Return the concatenation of this name, the given ASCII
  87      *  character, and name `n'.
  88      */
  89     public Name append(char c, Name n) {
  90         int len = getByteLength();
  91         byte[] bs = new byte[len + 1 + n.getByteLength()];
  92         getBytes(bs, 0);
  93         bs[len] = (byte) c;
  94         n.getBytes(bs, len+1);
  95         return table.fromUtf(bs, 0, bs.length);
  96     }
  97 
  98     /** An arbitrary but consistent complete order among all Names.
  99      */
 100     public int compareTo(Name other) {
 101         return other.getIndex() - this.getIndex();
 102     }
 103 
 104     /** Return true if this is the empty name.
 105      */
 106     public boolean isEmpty() {
 107         return getByteLength() == 0;
 108     }
 109 
 110     /** Returns last occurrence of byte b in this name, -1 if not found.
 111      */
 112     public int lastIndexOf(byte b) {
 113         byte[] bytes = getByteArray();
 114         int offset = getByteOffset();
 115         int i = getByteLength() - 1;
 116         while (i >= 0 && bytes[offset + i] != b) i--;
 117         return i;
 118     }
 119 
 120     /** Does this name start with prefix?
 121      */
 122     public boolean startsWith(Name prefix) {
 123         byte[] thisBytes = this.getByteArray();
 124         int thisOffset   = this.getByteOffset();
 125         int thisLength   = this.getByteLength();
 126         byte[] prefixBytes = prefix.getByteArray();
 127         int prefixOffset   = prefix.getByteOffset();
 128         int prefixLength   = prefix.getByteLength();
 129 
 130         if (thisLength < prefixLength)
 131             return false;
 132 
 133         int i = 0;
 134         while (i < prefixLength &&
 135                thisBytes[thisOffset + i] == prefixBytes[prefixOffset + i])
 136             i++;
 137         return i == prefixLength;
 138     }
 139 
 140     /** Returns the sub-name starting at position start, up to and
 141      *  excluding position end.
 142      */
 143     public Name subName(int start, int end) {
 144         if (end < start) end = start;
 145         return table.fromUtf(getByteArray(), getByteOffset() + start, end - start);
 146     }
 147 
 148     /** Return the string representation of this name.
 149      */
 150     @Override
 151     public String toString() {
 152         return Convert.utf2string(getByteArray(), getByteOffset(), getByteLength());
 153     }
 154 
 155     /** Return the Utf8 representation of this name.
 156      */
 157     public byte[] toUtf() {
 158         byte[] bs = new byte[getByteLength()];
 159         getBytes(bs, 0);
 160         return bs;
 161     }
 162 
 163     /* Get a "reasonably small" value that uniquely identifies this name
 164      * within its name table.
 165      */
 166     public abstract int getIndex();
 167 
 168     /** Get the length (in bytes) of this name.
 169      */
 170     public abstract int getByteLength();
 171 
 172     /** Returns i'th byte of this name.
 173      */
 174     public abstract byte getByteAt(int i);
 175 
 176     /** Copy all bytes of this name to buffer cs, starting at start.
 177      */
 178     public void getBytes(byte cs[], int start) {
 179         System.arraycopy(getByteArray(), getByteOffset(), cs, start, getByteLength());
 180     }
 181 
 182     /** Get the underlying byte array for this name. The contents of the
 183      * array must not be modified.
 184      */
 185     public abstract byte[] getByteArray();
 186 
 187     /** Get the start offset of this name within its byte array.
 188      */
 189     public abstract int getByteOffset();
 190 
 191     /** An abstraction for the hash table used to create unique Name instances.
 192      */
 193     public static abstract class Table {
 194         /** Standard name table.
 195          */
 196         public final Names names;
 197 
 198         Table(Names names) {
 199             this.names = names;
 200         }
 201 
 202         /** Get the name from the characters in cs[start..start+len-1].
 203          */
 204         public abstract Name fromChars(char[] cs, int start, int len);
 205 
 206         /** Get the name for the characters in string s.
 207          */
 208         public Name fromString(String s) {
 209             char[] cs = s.toCharArray();
 210             return fromChars(cs, 0, cs.length);
 211         }
 212 
 213         /** Get the name for the bytes in array cs.
 214          *  Assume that bytes are in utf8 format.
 215          */
 216         public Name fromUtf(byte[] cs) {
 217             return fromUtf(cs, 0, cs.length);
 218         }
 219 
 220         /** get the name for the bytes in cs[start..start+len-1].
 221          *  Assume that bytes are in utf8 format.
 222          */
 223         public abstract Name fromUtf(byte[] cs, int start, int len);
 224 
 225         /** Release any resources used by this table.
 226          */
 227         public abstract void dispose();
 228 
 229         /** The hashcode of a name.
 230          */
 231         protected static int hashValue(byte bytes[], int offset, int length) {
 232             int h = 0;
 233             int off = offset;
 234 
 235             for (int i = 0; i < length; i++) {
 236                 h = (h << 5) - h + bytes[off++];
 237             }
 238             return h;
 239         }
 240 
 241         /** Compare two subarrays
 242          */
 243         protected static boolean equals(byte[] bytes1, int offset1,
 244                 byte[] bytes2, int offset2, int length) {
 245             int i = 0;
 246             while (i < length && bytes1[offset1 + i] == bytes2[offset2 + i]) {
 247                 i++;
 248             }
 249             return i == length;
 250         }
 251     }
 252 }