1 /*
   2  * Copyright (c) 2016, 2017, 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 package jdk.tools.jaotc.binformat;
  25 
  26 import jdk.tools.jaotc.binformat.Symbol.Binding;
  27 import jdk.tools.jaotc.binformat.Symbol.Kind;
  28 import jdk.tools.jaotc.binformat.Container;
  29 
  30 import java.io.ByteArrayOutputStream;
  31 import java.nio.ByteBuffer;
  32 import java.nio.ByteOrder;
  33 import java.util.Arrays;
  34 
  35 /**
  36  * Base class that represents content of all sections with byte-level granularity. The ByteContainer
  37  * class is backed by a ByteArrayOutputStream. This class supports writing all desired byte content
  38  * to the container using the method {@code appendBytes} and accessing the byte array using the
  39  * method {@code getByteArray}.
  40  *
  41  * The method {@code putIntAt} updates the content of {@code contentBytes}. Changes are not
  42  * reflected in {@code contentStream}.
  43  */
  44 public class ByteContainer implements Container {
  45     /**
  46      * {@code ByteBuffer} representation of {@code BinaryContainer}.
  47      */
  48     private ByteBuffer contentBytes;
  49 
  50     /**
  51      * {@code ByteArrayoutputStream} to which all appends are done.
  52      */
  53     private ByteArrayOutputStream contentStream;
  54 
  55     /**
  56      * Boolean to indicate if contentBytes was modified.
  57      */
  58     private boolean bufferModified;
  59 
  60     /**
  61      * Boolean to indicate if this section contains any relocations.
  62      */
  63     private boolean hasRelocations;
  64 
  65     /**
  66      * Name of this container, used as section name.
  67      */
  68     private String containerName;
  69     private final SymbolTable symbolTable;
  70 
  71     /**
  72      * Contains a unique id.
  73      */
  74     private int sectionId = -1;
  75 
  76     /**
  77      * Construct a {@code ByteContainer} object.
  78      */
  79     public ByteContainer(String containerName, SymbolTable symbolTable) {
  80         this.containerName = containerName;
  81         this.symbolTable = symbolTable;
  82         this.contentBytes = null;
  83         this.bufferModified = false;
  84         this.hasRelocations = false;
  85         this.contentStream = new ByteArrayOutputStream();
  86     }
  87 
  88     /**
  89      * Update byte buffer to reflect the current contents of byte stream.
  90      *
  91      * @throws InternalError throws {@code InternalError} if buffer byte array was modified
  92      */
  93     private void updateByteBuffer() {
  94         if (!bufferModified) {
  95             contentBytes = ByteBuffer.wrap(contentStream.toByteArray());
  96             // Default byte order of ByteBuffer is BIG_ENDIAN.
  97             // Set it appropriately
  98             this.contentBytes.order(ByteOrder.nativeOrder());
  99         } else {
 100             throw new InternalError("Backing byte buffer no longer in sync with byte stream");
 101         }
 102     }
 103 
 104     /**
 105      * Get the byte array of {@code ByteContainer}.
 106      *
 107      * @return byte array
 108      * @throws InternalError throws {@code InternalError} if buffer byte array was modified
 109      */
 110     public byte[] getByteArray() {
 111         if (!bufferModified) {
 112             updateByteBuffer();
 113         }
 114         return contentBytes.array();
 115     }
 116 
 117     /**
 118      * Append to byte stream. It is an error to append to stream if the byte buffer version is
 119      * changed.
 120      *
 121      * @param newBytes new content
 122      * @param off offset start offset in {@code newBytes}
 123      * @param len length of data to write
 124      * @throws InternalError throws {@code InternalError} if buffer byte array was modified
 125      */
 126     public ByteContainer appendBytes(byte[] newBytes, int off, int len) {
 127         if (bufferModified) {
 128             throw new InternalError("Backing byte buffer no longer in sync with byte stream");
 129         }
 130         contentStream.write(newBytes, off, len);
 131         return this;
 132     }
 133 
 134     public ByteContainer appendBytes(byte[] newBytes) {
 135         appendBytes(newBytes, 0, newBytes.length);
 136         return this;
 137     }
 138 
 139     public ByteContainer appendInt(int i) {
 140         if (bufferModified) {
 141             throw new InternalError("Backing byte buffer no longer in sync with byte stream");
 142         }
 143         ByteBuffer b = ByteBuffer.allocate(Integer.BYTES);
 144         b.order(ByteOrder.nativeOrder());
 145         b.putInt(i);
 146         byte[] result = b.array();
 147         contentStream.write(result, 0, result.length);
 148         return this;
 149     }
 150 
 151     public ByteContainer appendInts(int[] newInts) {
 152         if (bufferModified) {
 153             throw new InternalError("Backing byte buffer no longer in sync with byte stream");
 154         }
 155         ByteBuffer b = ByteBuffer.allocate(Integer.BYTES * newInts.length).order(ByteOrder.nativeOrder());
 156         Arrays.stream(newInts).forEach(i -> b.putInt(i));
 157         byte[] result = b.array();
 158         contentStream.write(result, 0, result.length);
 159         return this;
 160     }
 161 
 162     public void appendLong(long l) {
 163         if (bufferModified) {
 164             throw new InternalError("Backing byte buffer no longer in sync with byte stream");
 165         }
 166         ByteBuffer b = ByteBuffer.allocate(8);
 167         b.order(ByteOrder.nativeOrder());
 168         b.putLong(l);
 169         byte[] result = b.array();
 170         contentStream.write(result, 0, result.length);
 171     }
 172 
 173     /**
 174      * Return the current size of byte stream backing the BinaryContainer.
 175      *
 176      * @return size of buffer stream
 177      */
 178     public int getByteStreamSize() {
 179         return contentStream.size();
 180     }
 181 
 182     /**
 183      * Return the name of this container.
 184      *
 185      * @return string containing name
 186      */
 187     public String getContainerName() {
 188         return containerName;
 189     }
 190 
 191     /**
 192      * Modify the byte buffer version of the byte output stream. Note that after calling this method
 193      * all further updates to BinaryContainer will be out of sync with byte buffer content.
 194      *
 195      * @param index index of byte to be changed
 196      * @param value new value
 197      */
 198     public void putIntAt(int index, int value) {
 199         if (!bufferModified) {
 200             updateByteBuffer();
 201         }
 202         contentBytes.putInt(index, value);
 203         bufferModified = true;
 204     }
 205 
 206     public void putLongAt(int index, long value) {
 207         if (!bufferModified) {
 208             updateByteBuffer();
 209         }
 210         contentBytes.putLong(index, value);
 211         bufferModified = true;
 212     }
 213 
 214     public void setSectionId(int id) {
 215         if (sectionId != -1) {
 216             throw new InternalError("Assigning new sectionId (old: " + sectionId + ", new: " + id + ")");
 217         }
 218         sectionId = id;
 219     }
 220 
 221     public int getSectionId() {
 222         if (sectionId == -1) {
 223             throw new InternalError("Using sectionId before assigned");
 224         }
 225         return sectionId;
 226     }
 227 
 228     public Symbol createSymbol(int offset, Kind kind, Binding binding, int size, String name) {
 229         Symbol symbol = new Symbol(offset, kind, binding, this, size, name);
 230         symbolTable.addSymbol(symbol);
 231         return symbol;
 232     }
 233 
 234     public GotSymbol createGotSymbol(String name) {
 235         GotSymbol symbol = new GotSymbol(Kind.OBJECT, Binding.LOCAL, this, name);
 236         symbolTable.addSymbol(symbol);
 237         return symbol;
 238     }
 239 
 240     public GotSymbol createGotSymbol(int offset, String name) {
 241         GotSymbol symbol = new GotSymbol(offset, Kind.OBJECT, Binding.LOCAL, this, name);
 242         symbolTable.addSymbol(symbol);
 243         return symbol;
 244     }
 245 
 246     public void clear() {
 247         this.contentBytes = null;
 248         this.contentStream = null;
 249     }
 250 
 251     public void setHasRelocations() {
 252         this.hasRelocations = true;
 253     }
 254 
 255     public boolean hasRelocations() {
 256         return this.hasRelocations;
 257     }
 258 }