mcs/tools/pdb2mdb/DataStream.cs

   1 //-----------------------------------------------------------------------------
   2 //
   3 // Copyright (C) Microsoft Corporation.  All Rights Reserved.
   4 //
   5 //-----------------------------------------------------------------------------
   6 using System;
   7 using System.IO;
   8
   9 namespace Microsoft.Cci.Pdb {
  10   internal class DataStream {
  11     internal DataStream() {
  12       this.contentSize = 0;
  13       this.pages = null;
  14     }
  15
  16     internal DataStream(int contentSize, BitAccess bits, int count) {
  17       this.contentSize = contentSize;
  18       if (count > 0) {
  19         this.pages = new int[count];
  20         bits.ReadInt32(this.pages);
  21       }
  22     }
  23
  24     internal void Read(PdbReader reader, BitAccess bits) {
  25       bits.MinCapacity(contentSize);
  26       Read(reader, 0, bits.Buffer, 0, contentSize);
  27     }
  28
  29     internal void Read(PdbReader reader, int position,
  30                      byte[] bytes, int offset, int data) {
  31       if (position + data > contentSize) {
  32         throw new PdbException("DataStream can't read off end of stream. " +
  33                                        "(pos={0},siz={1})",
  34                                position, data);
  35       }
  36       if (position == contentSize) {
  37         return;
  38       }
  39
  40       int left = data;
  41       int page = position / reader.pageSize;
  42       int rema = position % reader.pageSize;
  43
  44       // First get remained of first page.
  45       if (rema != 0) {
  46         int todo = reader.pageSize - rema;
  47         if (todo > left) {
  48           todo = left;
  49         }
  50
  51         reader.Seek(pages[page], rema);
  52         reader.Read(bytes, offset, todo);
  53
  54         offset += todo;
  55         left -= todo;
  56         page++;
  57       }
  58
  59       // Now get the remaining pages.
  60       while (left > 0) {
  61         int todo = reader.pageSize;
  62         if (todo > left) {
  63           todo = left;
  64         }
  65
  66         reader.Seek(pages[page], 0);
  67         reader.Read(bytes, offset, todo);
  68
  69         offset += todo;
  70         left -= todo;
  71         page++;
  72       }
  73     }
  74
  75     internal void Write(PdbWriter writer, byte[] bytes) {
  76       Write(writer, bytes, bytes.Length);
  77     }
  78
  79     internal void Write(PdbWriter writer, byte[] bytes, int data) {
  80       if (bytes == null || data == 0) {
  81         return;
  82       }
  83
  84       int left = data;
  85       int used = 0;
  86       int rema = contentSize % writer.pageSize;
  87       if (rema != 0) {
  88         int todo = writer.pageSize - rema;
  89         if (todo > left) {
  90           todo = left;
  91         }
  92
  93         int lastPage = pages[pages.Length - 1];
  94         writer.Seek(lastPage, rema);
  95         writer.Write(bytes, used, todo);
  96         used += todo;
  97         left -= todo;
  98       }
  99
 100       if (left > 0) {
 101         int count = (left + writer.pageSize - 1) / writer.pageSize;
 102         int page0 = writer.AllocatePages(count);
 103
 104         writer.Seek(page0, 0);
 105         writer.Write(bytes, used, left);
 106
 107         AddPages(page0, count);
 108       }
 109
 110       contentSize += data;
 111     }
 112
 113     private void AddPages(int page0, int count) {
 114       if (pages == null) {
 115         pages = new int[count];
 116         for (int i = 0; i < count; i++) {
 117           pages[i] = page0 + i;
 118         }
 119       } else {
 120         int[] old = pages;
 121         int used = old.Length;
 122
 123         pages = new int[used + count];
 124         Array.Copy(old, pages, used);
 125         for (int i = 0; i < count; i++) {
 126           pages[used + i] = page0 + i;
 127         }
 128       }
 129     }
 130
 131     internal int Pages {
 132       get { return pages == null ? 0 : pages.Length; }
 133     }
 134
 135     internal int Length {
 136       get { return contentSize; }
 137     }
 138
 139     internal int GetPage(int index) {
 140       return pages[index];
 141     }
 142
 143     internal int contentSize;
 144     internal int[] pages;
 145   }
 146 }