mcs/class/Mono.PEToolkit/PEUtils.cs

   1
   2 //
   3 // Permission is hereby granted, free of charge, to any person obtaining
   4 // a copy of this software and associated documentation files (the
   5 // "Software"), to deal in the Software without restriction, including
   6 // without limitation the rights to use, copy, modify, merge, publish,
   7 // distribute, sublicense, and/or sell copies of the Software, and to
   8 // permit persons to whom the Software is furnished to do so, subject to
   9 // the following conditions:
  10 //
  11 // The above copyright notice and this permission notice shall be
  12 // included in all copies or substantial portions of the Software.
  13 //
  14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  15 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  16 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  17 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  18 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  19 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  20 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  21 //
  22 /*
  23  * Copyright (c) 2002 Sergey Chaban <serge@wildwestsoftware.com>
  24  */
  25
  26 using System;
  27 using System.IO;
  28 using System.Text;
  29 using System.Reflection;
  30 using System.Runtime.InteropServices;
  31
  32 namespace Mono.PEToolkit {
  33
  34         public sealed class PEUtils {
  35
  36                 private PEUtils()
  37                 {
  38                 }
  39
  40
  41                 unsafe internal static string GetString (sbyte* data, int start, int len, Encoding encoding)
  42                 {
  43                         byte[] data_array = new byte[len-start];
  44
  45                         for (int i=start; i<len; i++)
  46                                 data_array[i-start] = (byte)*data++;
  47
  48                         return encoding.GetString (data_array);
  49                 }
  50
  51                 /// <summary>
  52                 /// Reads structure from the input stream preserving its endianess.
  53                 /// </summary>
  54                 /// <param name="reader"></param>
  55                 /// <param name="pStruct"></param>
  56                 /// <param name="len"></param>
  57                 unsafe internal static void ReadStruct(BinaryReader reader, void* pStruct, int len)
  58                 {
  59                         byte* p = (byte*) pStruct;
  60
  61                         if (System.BitConverter.IsLittleEndian) {
  62                                 // On a little-endian machine read data in 64-bit chunks,
  63                                 // this won't work on big-endian machine because
  64                                 // BinaryReader APIs are little-endian while
  65                                 // memory writes are platform-native.
  66                                 // This seems faster than ReadBytes/Copy method
  67                                 // in the "else" clause, especially if used often
  68                                 // (no extra memory allocation for byte[]?).
  69                                 int whole = len >> 3;
  70                                 int rem = len & 7;
  71
  72                                 for (int i = whole; --i >= 0;) {
  73                                         long qw = reader.ReadInt64();
  74                                         Marshal.WriteInt64((IntPtr) p, qw);
  75                                         p += sizeof (long);
  76                                 }
  77                                 for (int i = rem; --i >= 0;) {
  78                                         *p++ = (byte) reader.ReadByte();
  79                                 }
  80                         } else {
  81                                 byte [] buff = reader.ReadBytes(len);
  82                                 Marshal.Copy(buff, 0, (IntPtr) p, len);
  83                         }
  84                 }
  85
  86                 /// <summary>
  87                 /// Reads structure from the input stream
  88                 /// changing its endianess if required
  89                 /// (if running on big-endian hardware).
  90                 /// </summary>
  91                 /// <param name="reader"></param>
  92                 /// <param name="pStruct"></param>
  93                 /// <param name="len"></param>
  94                 /// <param name="type"></param>
  95                 unsafe internal static void ReadStruct(BinaryReader reader, void* pStruct, int len, Type type)
  96                 {
  97                         ReadStruct(reader, pStruct, len);
  98                         if (!System.BitConverter.IsLittleEndian) {
  99                                 ChangeStructEndianess(pStruct, type);
 100                         }
 101                 }
 102
 103
 104                 unsafe private static int SwapByTypeCode(byte* p, TypeCode tcode)
 105                 {
 106                         int inc = 0;
 107                         switch (tcode) {
 108                                 case TypeCode.Int16 :
 109                                         short* sp = (short*) p;
 110                                         short sx = *sp;
 111                                         sx = LEBitConverter.SwapInt16(sx);
 112                                         *sp = sx;
 113                                         inc = sizeof (short);
 114                                         break;
 115                                 case TypeCode.UInt16 :
 116                                         ushort* usp = (ushort*) p;
 117                                         ushort usx = *usp;
 118                                         usx = LEBitConverter.SwapUInt16(usx);
 119                                         *usp = usx;
 120                                         inc = sizeof (ushort);
 121                                         break;
 122                                 case TypeCode.Int32 :
 123                                         int* ip = (int*) p;
 124                                         int ix = *ip;
 125                                         ix = LEBitConverter.SwapInt32(ix);
 126                                         *ip = ix;
 127                                         inc = sizeof (int);
 128                                         break;
 129                                 case TypeCode.UInt32 :
 130                                         uint* uip = (uint*) p;
 131                                         uint uix = *uip;
 132                                         uix = LEBitConverter.SwapUInt32(uix);
 133                                         *uip = uix;
 134                                         inc = sizeof (uint);
 135                                         break;
 136                                 case TypeCode.Int64 :
 137                                         long* lp = (long*) p;
 138                                         long lx = *lp;
 139                                         lx = LEBitConverter.SwapInt64(lx);
 140                                         *lp = lx;
 141                                         inc = sizeof (long);
 142                                         break;
 143                                 case TypeCode.UInt64 :
 144                                         ulong* ulp = (ulong*) p;
 145                                         ulong ulx = *ulp;
 146                                         ulx = LEBitConverter.SwapUInt64(ulx);
 147                                         *ulp = ulx;
 148                                         inc = sizeof (ulong);
 149                                         break;
 150                                 case TypeCode.Byte :
 151                                 case TypeCode.SByte :
 152                                         inc = sizeof (byte);
 153                                         break;
 154                                 default :
 155                                         break;
 156                         }
 157                         return inc;
 158                 }
 159
 160                 unsafe internal static int ChangeStructEndianess(void* pStruct, Type type)
 161                 {
 162                         if (type == null || !type.IsValueType) return 0;
 163                         if (!type.IsLayoutSequential && !type.IsExplicitLayout) {
 164                                 throw new Exception("Internal error: struct must have explicit or sequential layout.");
 165                         }
 166
 167                         bool seq = type.IsLayoutSequential;
 168                         byte* p = (byte*) pStruct;
 169                         int offs = 0;
 170                         int inc;
 171                         FieldInfo [] fields = type.GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
 172
 173                         foreach (FieldInfo fi in fields) {
 174                                 if (!seq) offs = Marshal.OffsetOf(type, fi.Name).ToInt32 ();
 175                                 Type ft = fi.FieldType;
 176                                 TypeCode tcode = Type.GetTypeCode(ft);
 177                                 if (tcode == TypeCode.Object) {
 178                                         // not a primitive type, process recursively.
 179                                         inc = ChangeStructEndianess(p + offs, ft);
 180                                 } else {
 181                                         inc = SwapByTypeCode(p + offs, tcode);
 182                                 }
 183                                 if (seq) offs += inc;
 184                         }
 185
 186                         return offs;
 187                 }
 188
 189         }
 190
 191 }
 192