Imported Upstream version 5.0.0.42

Former-commit-id: fd56571888259555122d8a0f58c68838229cea2b

external/linker/cecil/symbols/pdb/Microsoft.Cci.Pdb/PdbFileHeader.cs

@@ -0,0 +1,95 @@
+//-----------------------------------------------------------------------------
+//
+// Copyright (c) Microsoft. All rights reserved.
+// This code is licensed under the Microsoft Public License.
+// THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
+// ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
+// IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
+// PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
+//
+//-----------------------------------------------------------------------------
+using System;
+using System.IO;
+using System.Text;
+
+namespace Microsoft.Cci.Pdb {
+  internal class PdbFileHeader {
+    //internal PdbFileHeader(int pageSize) {
+    //  this.magic = new byte[32] {
+    //            0x4D, 0x69, 0x63, 0x72, 0x6F, 0x73, 0x6F, 0x66, // "Microsof"
+    //            0x74, 0x20, 0x43, 0x2F, 0x43, 0x2B, 0x2B, 0x20, // "t C/C++ "
+    //            0x4D, 0x53, 0x46, 0x20, 0x37, 0x2E, 0x30, 0x30, // "MSF 7.00"
+    //            0x0D, 0x0A, 0x1A, 0x44, 0x53, 0x00, 0x00, 0x00  // "^^^DS^^^"
+    //        };
+    //  this.pageSize = pageSize;
+    //}
+
+    const string MAGIC = "Microsoft C/C++ MSF 7.00";
+
+    internal PdbFileHeader(Stream reader, BitAccess bits) {
+      bits.MinCapacity(56);
+      reader.Seek(0, SeekOrigin.Begin);
+      bits.FillBuffer(reader, 52);
+
+      this.magic = new byte[32];
+      bits.ReadBytes(this.magic);                 //   0..31
+      bits.ReadInt32(out this.pageSize);          //  32..35
+      bits.ReadInt32(out this.freePageMap);       //  36..39
+      bits.ReadInt32(out this.pagesUsed);         //  40..43
+      bits.ReadInt32(out this.directorySize);     //  44..47
+      bits.ReadInt32(out this.zero);              //  48..51
+
+      if (Magic != MAGIC) {
+        throw new InvalidOperationException("Magic is wrong.");
+      }
+      int directoryPages = ((((directorySize + pageSize - 1) / pageSize) * 4) + pageSize - 1) / pageSize;
+      this.directoryRoot = new int[directoryPages];
+      bits.FillBuffer(reader, directoryPages * 4);
+      bits.ReadInt32(this.directoryRoot);
+    }
+
+    string Magic {
+      get { return StringFromBytesUTF8(magic, 0, MAGIC.Length); }
+    }
+
+    //internal void Write(Stream writer, BitAccess bits) {
+    //  bits.MinCapacity(pageSize);
+    //  bits.WriteBytes(magic);                     //   0..31
+    //  bits.WriteInt32(pageSize);                  //  32..35
+    //  bits.WriteInt32(freePageMap);               //  36..39
+    //  bits.WriteInt32(pagesUsed);                 //  40..43
+    //  bits.WriteInt32(directorySize);             //  44..47
+    //  bits.WriteInt32(zero);                      //  48..51
+    //  bits.WriteInt32(directoryRoot);             //  52..55
+
+    //  writer.Seek(0, SeekOrigin.Begin);
+    //  bits.WriteBuffer(writer, pageSize);
+    //}
+
+    //////////////////////////////////////////////////// Helper Functions.
+    //
+    static string StringFromBytesUTF8(byte[] bytes) {
+      return StringFromBytesUTF8(bytes, 0, bytes.Length);
+    }
+
+    static string StringFromBytesUTF8(byte[] bytes, int offset, int length) {
+      for (int i = 0; i < length; i++) {
+        if (bytes[offset + i] < ' ') {
+          length = i;
+        }
+      }
+      return Encoding.UTF8.GetString(bytes, offset, length);
+    }
+
+    ////////////////////////////////////////////////////////////// Fields.
+    //
+    internal readonly byte[] magic;
+    internal readonly int pageSize;
+    internal int freePageMap;
+    internal int pagesUsed;
+    internal int directorySize;
+    internal readonly int zero;
+    internal int[] directoryRoot;
+  }
+
+}