mcs/class/Mono.Cecil/Mono.Cecil.PE/ByteBuffer.cs

   1 //
   2 // ByteBuffer.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@gmail.com)
   6 //
   7 // Copyright (c) 2008 - 2010 Jb Evain
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30
  31 namespace Mono.Cecil.PE {
  32
  33         class ByteBuffer {
  34
  35                 internal byte [] buffer;
  36                 internal int length;
  37                 internal int position;
  38
  39                 public ByteBuffer ()
  40                 {
  41                         this.buffer = Empty<byte>.Array;
  42                 }
  43
  44                 public ByteBuffer (int length)
  45                 {
  46                         this.buffer = new byte [length];
  47                 }
  48
  49                 public ByteBuffer (byte [] buffer)
  50                 {
  51                         this.buffer = buffer ?? Empty<byte>.Array;
  52                         this.length = this.buffer.Length;
  53                 }
  54
  55                 public void Reset (byte [] buffer)
  56                 {
  57                         this.buffer = buffer ?? Empty<byte>.Array;
  58                         this.length = this.buffer.Length;
  59                 }
  60
  61                 public void Advance (int length)
  62                 {
  63                         position += length;
  64                 }
  65
  66                 public byte ReadByte ()
  67                 {
  68                         return buffer [position++];
  69                 }
  70
  71                 public sbyte ReadSByte ()
  72                 {
  73                         return (sbyte) ReadByte ();
  74                 }
  75
  76                 public byte [] ReadBytes (int length)
  77                 {
  78                         var bytes = new byte [length];
  79                         Buffer.BlockCopy (buffer, position, bytes, 0, length);
  80                         position += length;
  81                         return bytes;
  82                 }
  83
  84                 public ushort ReadUInt16 ()
  85                 {
  86                         ushort value = (ushort) (buffer [position]
  87                                 | (buffer [position + 1] << 8));
  88                         position += 2;
  89                         return value;
  90                 }
  91
  92                 public short ReadInt16 ()
  93                 {
  94                         return (short) ReadUInt16 ();
  95                 }
  96
  97                 public uint ReadUInt32 ()
  98                 {
  99                         uint value = (uint) (buffer [position]
 100                                 | (buffer [position + 1] << 8)
 101                                 | (buffer [position + 2] << 16)
 102                                 | (buffer [position + 3] << 24));
 103                         position += 4;
 104                         return value;
 105                 }
 106
 107                 public int ReadInt32 ()
 108                 {
 109                         return (int) ReadUInt32 ();
 110                 }
 111
 112                 public ulong ReadUInt64 ()
 113                 {
 114                         uint low = ReadUInt32 ();
 115                         uint high = ReadUInt32 ();
 116
 117                         return (((ulong) high) << 32) | low;
 118                 }
 119
 120                 public long ReadInt64 ()
 121                 {
 122                         return (long) ReadUInt64 ();
 123                 }
 124
 125                 public uint ReadCompressedUInt32 ()
 126                 {
 127                         byte first = ReadByte ();
 128                         if ((first & 0x80) == 0)
 129                                 return first;
 130
 131                         if ((first & 0x40) == 0)
 132                                 return ((uint) (first & ~0x80) << 8)
 133                                         | ReadByte ();
 134
 135                         return ((uint) (first & ~0xc0) << 24)
 136                                 | (uint) ReadByte () << 16
 137                                 | (uint) ReadByte () << 8
 138                                 | ReadByte ();
 139                 }
 140
 141                 public int ReadCompressedInt32 ()
 142                 {
 143                         var value = (int) ReadCompressedUInt32 ();
 144
 145                         return (value & 1) != 0
 146                                 ? -(value >> 1)
 147                                 : value >> 1;
 148                 }
 149
 150                 public float ReadSingle ()
 151                 {
 152                         if (!BitConverter.IsLittleEndian) {
 153                                 var bytes = ReadBytes (4);
 154                                 Array.Reverse (bytes);
 155                                 return BitConverter.ToSingle (bytes, 0);
 156                         }
 157
 158                         float value = BitConverter.ToSingle (buffer, position);
 159                         position += 4;
 160                         return value;
 161                 }
 162
 163                 public double ReadDouble ()
 164                 {
 165                         if (!BitConverter.IsLittleEndian) {
 166                                 var bytes = ReadBytes (8);
 167                                 Array.Reverse (bytes);
 168                                 return BitConverter.ToDouble (bytes, 0);
 169                         }
 170
 171                         double value = BitConverter.ToDouble (buffer, position);
 172                         position += 8;
 173                         return value;
 174                 }
 175
 176 #if !READ_ONLY
 177
 178                 public void WriteByte (byte value)
 179                 {
 180                         if (position == buffer.Length)
 181                                 Grow (1);
 182
 183                         buffer [position++] = value;
 184
 185                         if (position > length)
 186                                 length = position;
 187                 }
 188
 189                 public void WriteSByte (sbyte value)
 190                 {
 191                         WriteByte ((byte) value);
 192                 }
 193
 194                 public void WriteUInt16 (ushort value)
 195                 {
 196                         if (position + 2 > buffer.Length)
 197                                 Grow (2);
 198
 199                         buffer [position++] = (byte) value;
 200                         buffer [position++] = (byte) (value >> 8);
 201
 202                         if (position > length)
 203                                 length = position;
 204                 }
 205
 206                 public void WriteInt16 (short value)
 207                 {
 208                         WriteUInt16 ((ushort) value);
 209                 }
 210
 211                 public void WriteUInt32 (uint value)
 212                 {
 213                         if (position + 4 > buffer.Length)
 214                                 Grow (4);
 215
 216                         buffer [position++] = (byte) value;
 217                         buffer [position++] = (byte) (value >> 8);
 218                         buffer [position++] = (byte) (value >> 16);
 219                         buffer [position++] = (byte) (value >> 24);
 220
 221                         if (position > length)
 222                                 length = position;
 223                 }
 224
 225                 public void WriteInt32 (int value)
 226                 {
 227                         WriteUInt32 ((uint) value);
 228                 }
 229
 230                 public void WriteUInt64 (ulong value)
 231                 {
 232                         if (position + 8 > buffer.Length)
 233                                 Grow (8);
 234
 235                         buffer [position++] = (byte) value;
 236                         buffer [position++] = (byte) (value >> 8);
 237                         buffer [position++] = (byte) (value >> 16);
 238                         buffer [position++] = (byte) (value >> 24);
 239                         buffer [position++] = (byte) (value >> 32);
 240                         buffer [position++] = (byte) (value >> 40);
 241                         buffer [position++] = (byte) (value >> 48);
 242                         buffer [position++] = (byte) (value >> 56);
 243
 244                         if (position > length)
 245                                 length = position;
 246                 }
 247
 248                 public void WriteInt64 (long value)
 249                 {
 250                         WriteUInt64 ((ulong) value);
 251                 }
 252
 253                 public void WriteCompressedUInt32 (uint value)
 254                 {
 255                         if (value < 0x80)
 256                                 WriteByte ((byte) value);
 257                         else if (value < 0x4000) {
 258                                 WriteByte ((byte) (0x80 | (value >> 8)));
 259                                 WriteByte ((byte) (value & 0xff));
 260                         } else {
 261                                 WriteByte ((byte) ((value >> 24) | 0xc0));
 262                                 WriteByte ((byte) ((value >> 16) & 0xff));
 263                                 WriteByte ((byte) ((value >> 8) & 0xff));
 264                                 WriteByte ((byte) (value & 0xff));
 265                         }
 266                 }
 267
 268                 public void WriteCompressedInt32 (int value)
 269                 {
 270                         WriteCompressedUInt32 ((uint) ((value < 0) ? ((-value) << 1) | 1 : value << 1));
 271                 }
 272
 273                 public void WriteBytes (byte [] bytes)
 274                 {
 275                         var length = bytes.Length;
 276                         if (position + length > buffer.Length)
 277                                 Grow (length);
 278
 279                         Buffer.BlockCopy (bytes, 0, buffer, position, length);
 280                         position += length;
 281
 282                         if (position > this.length)
 283                                 this.length = position;
 284                 }
 285
 286                 public void WriteBytes (int length)
 287                 {
 288                         if (position + length > buffer.Length)
 289                                 Grow (length);
 290
 291                         position += length;
 292
 293                         if (position > this.length)
 294                                 this.length = position;
 295                 }
 296
 297                 public void WriteBytes (ByteBuffer buffer)
 298                 {
 299                         if (position + buffer.length > this.buffer.Length)
 300                                 Grow (buffer.length);
 301
 302                         Buffer.BlockCopy (buffer.buffer, 0, this.buffer, position, buffer.length);
 303                         position += buffer.length;
 304
 305                         if (position > this.length)
 306                                 this.length = position;
 307                 }
 308
 309                 public void WriteSingle (float value)
 310                 {
 311                         var bytes = BitConverter.GetBytes (value);
 312
 313                         if (!BitConverter.IsLittleEndian)
 314                                 Array.Reverse (bytes);
 315
 316                         WriteBytes (bytes);
 317                 }
 318
 319                 public void WriteDouble (double value)
 320                 {
 321                         var bytes = BitConverter.GetBytes (value);
 322
 323                         if (!BitConverter.IsLittleEndian)
 324                                 Array.Reverse (bytes);
 325
 326                         WriteBytes (bytes);
 327                 }
 328
 329                 void Grow (int desired)
 330                 {
 331                         var current = this.buffer;
 332                         var current_length = current.Length;
 333
 334                         var buffer = new byte [System.Math.Max (current_length + desired, current_length * 2)];
 335                         Buffer.BlockCopy (current, 0, buffer, 0, current_length);
 336                         this.buffer = buffer;
 337                 }
 338
 339 #endif
 340
 341         }
 342 }