mcs/class/Mono.Profiler.Log/Mono.Profiler.Log/LogReader.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 using System;
   6 using System.IO;
   7 using System.Text;
   8
   9 namespace Mono.Profiler.Log {
  10
  11         sealed class LogReader : IDisposable {
  12
  13                 static readonly Encoding _encoding = Encoding.UTF8;
  14
  15                 readonly BinaryReader _reader;
  16
  17                 byte[] _stringBuffer = new byte [1024];
  18
  19                 public LogReader (Stream stream, bool leaveOpen)
  20                 {
  21                         _reader = new BinaryReader (stream, _encoding, leaveOpen);
  22                 }
  23
  24                 public void Dispose ()
  25                 {
  26                         _reader.Dispose ();
  27                 }
  28
  29                 public byte[] ReadBytes (int count)
  30                 {
  31                         var bytes = new byte [count];
  32
  33                         // BinaryReader.ReadBytes doesn't necessarily read the specified
  34                         // amount of bytes, so just do it this way.
  35                         for (var i = 0; i < bytes.Length; i++)
  36                                 bytes [i] = ReadByte ();
  37
  38                         return bytes;
  39                 }
  40
  41                 public byte ReadByte ()
  42                 {
  43                         return _reader.ReadByte ();
  44                 }
  45
  46                 public ushort ReadUInt16 ()
  47                 {
  48                         return _reader.ReadUInt16 ();
  49                 }
  50
  51                 public int ReadInt32 ()
  52                 {
  53                         return _reader.ReadInt32 ();
  54                 }
  55
  56                 public long ReadInt64 ()
  57                 {
  58                         return _reader.ReadInt64 ();
  59                 }
  60
  61                 public ulong ReadUInt64 ()
  62                 {
  63                         return _reader.ReadUInt64 ();
  64                 }
  65
  66                 public double ReadDouble ()
  67                 {
  68                         return _reader.ReadDouble ();
  69                 }
  70
  71                 public string ReadHeaderString ()
  72                 {
  73                         return _encoding.GetString (ReadBytes (ReadInt32 ()));
  74                 }
  75
  76                 public string ReadCString ()
  77                 {
  78                         var pos = 0;
  79
  80                         byte val;
  81
  82                         while ((val = ReadByte ()) != 0) {
  83                                 if (pos == _stringBuffer.Length)
  84                                         Array.Resize (ref _stringBuffer, System.Math.Max (_stringBuffer.Length * 2, pos + 1));
  85
  86                                 _stringBuffer [pos++] = val;
  87                         }
  88
  89                         return _encoding.GetString (_stringBuffer, 0, pos);
  90                 }
  91
  92                 public long ReadSLeb128 ()
  93                 {
  94                         long result = 0;
  95                         var shift = 0;
  96
  97                         while (true) {
  98                                 var b = ReadByte ();
  99
 100                                 result |= (long) (b & 0x7f) << shift;
 101                                 shift += 7;
 102
 103                                 if ((b & 0x80) != 0x80) {
 104                                         if (shift < sizeof (long) * 8 && (b & 0x40) == 0x40)
 105                                                 result |= -(1L << shift);
 106
 107                                         break;
 108                                 }
 109                         }
 110
 111                         return result;
 112                 }
 113
 114                 public ulong ReadULeb128 ()
 115                 {
 116                         ulong result = 0;
 117                         var shift = 0;
 118
 119                         while (true) {
 120                                 var b = ReadByte ();
 121
 122                                 result |= (ulong) (b & 0x7f) << shift;
 123
 124                                 if ((b & 0x80) != 0x80)
 125                                         break;
 126
 127                                 shift += 7;
 128                         }
 129
 130                         return result;
 131                 }
 132         }
 133 }