/
SequencePointCollection.cs
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/
SequencePointCollection.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection.Internal;
using System.Reflection.Metadata.Ecma335;
namespace System.Reflection.Metadata
{
public readonly struct SequencePointCollection : IEnumerable<SequencePoint>
{
private readonly MemoryBlock _block;
private readonly DocumentHandle _document;
internal SequencePointCollection(MemoryBlock block, DocumentHandle document)
{
_block = block;
_document = document;
}
public Enumerator GetEnumerator()
{
return new Enumerator(_block, _document);
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
IEnumerator<SequencePoint> IEnumerable<SequencePoint>.GetEnumerator()
{
return GetEnumerator();
}
public struct Enumerator : IEnumerator<SequencePoint>
{
private BlobReader _reader;
private SequencePoint _current;
private int _previousNonHiddenStartLine;
private ushort _previousNonHiddenStartColumn;
internal Enumerator(MemoryBlock block, DocumentHandle document)
{
_reader = new BlobReader(block);
_current = new SequencePoint(document, -1);
_previousNonHiddenStartLine = -1;
_previousNonHiddenStartColumn = 0;
}
public bool MoveNext()
{
if (_reader.RemainingBytes == 0)
{
return false;
}
DocumentHandle document = _current.Document;
int offset, deltaLines, deltaColumns, startLine;
ushort startColumn;
if (_reader.Offset == 0)
{
// header (skip local signature rid):
_reader.ReadCompressedInteger();
if (document.IsNil)
{
document = ReadDocumentHandle();
}
// IL offset:
offset = _reader.ReadCompressedInteger();
}
else
{
// skip all document records and update the current document accordingly:
int deltaOffset;
while ((deltaOffset = _reader.ReadCompressedInteger()) == 0)
{
document = ReadDocumentHandle();
}
// IL offset:
offset = AddOffsets(_current.Offset, deltaOffset);
}
ReadDeltaLinesAndColumns(out deltaLines, out deltaColumns);
// hidden
if (deltaLines == 0 && deltaColumns == 0)
{
_current = new SequencePoint(document, offset);
return true;
}
// delta Start Line & Column:
if (_previousNonHiddenStartLine < 0)
{
Debug.Assert(_previousNonHiddenStartColumn == 0);
startLine = ReadLine();
startColumn = ReadColumn();
}
else
{
startLine = AddLines(_previousNonHiddenStartLine, _reader.ReadCompressedSignedInteger());
startColumn = AddColumns(_previousNonHiddenStartColumn, _reader.ReadCompressedSignedInteger());
}
_previousNonHiddenStartLine = startLine;
_previousNonHiddenStartColumn = startColumn;
_current = new SequencePoint(
document,
offset,
startLine,
startColumn,
AddLines(startLine, deltaLines),
AddColumns(startColumn, deltaColumns));
return true;
}
private void ReadDeltaLinesAndColumns(out int deltaLines, out int deltaColumns)
{
deltaLines = _reader.ReadCompressedInteger();
deltaColumns = (deltaLines == 0) ? _reader.ReadCompressedInteger() : _reader.ReadCompressedSignedInteger();
}
private int ReadLine()
{
return _reader.ReadCompressedInteger();
}
private ushort ReadColumn()
{
int column = _reader.ReadCompressedInteger();
if (column > ushort.MaxValue)
{
Throw.SequencePointValueOutOfRange();
}
return (ushort)column;
}
private static int AddOffsets(int value, int delta)
{
int result = unchecked(value + delta);
if (result < 0)
{
Throw.SequencePointValueOutOfRange();
}
return result;
}
private static int AddLines(int value, int delta)
{
int result = unchecked(value + delta);
if (result < 0 || result >= SequencePoint.HiddenLine)
{
Throw.SequencePointValueOutOfRange();
}
return result;
}
private static ushort AddColumns(ushort value, int delta)
{
int result = unchecked(value + delta);
if (result < 0 || result >= ushort.MaxValue)
{
Throw.SequencePointValueOutOfRange();
}
return (ushort)result;
}
private DocumentHandle ReadDocumentHandle()
{
int rowId = _reader.ReadCompressedInteger();
if (rowId == 0 || !TokenTypeIds.IsValidRowId(rowId))
{
Throw.InvalidHandle();
}
return DocumentHandle.FromRowId(rowId);
}
public SequencePoint Current
{
get { return _current; }
}
object IEnumerator.Current
{
get { return _current; }
}
public void Reset()
{
_reader.Reset();
_current = default(SequencePoint);
}
void IDisposable.Dispose()
{
}
}
}
}