public void MoveAfterSizeHasIncreased()
{
Debug.Assert(Size > NextInSize.Size);
var next = NextInSize;
var prev = PrevInSize;
if (prev != null)
{
prev.NextInSize = next;
}
else
{
Smallest = next;
}
next.PrevInSize = prev;
prev = next;
next = next.NextInSize;
while (next != null && next.Size < Size)
{
prev = next;
next = next.NextInSize;
}
PrevInSize = prev;
prev.NextInSize = this;
NextInSize = next;
if (next != null)
{
next.PrevInSize = this;
}
else
{
Largest = this;
}
}
public FreeChunk(PoolSegment segment, FreeChunk prevInSegment, FreeChunk nextInSegment, int index, int size)
{
Debug.Assert(index >= 0 && size > 0 && index + size <= segment.Size);
Segment = segment;
Index = index;
Size = size;
PrevInSegment = prevInSegment;
NextInSegment = nextInSegment;
if (prevInSegment != null)
{
Debug.Assert(prevInSegment.Index + prevInSegment.Size < index);
prevInSegment.NextInSegment = this;
}
else
{
Debug.Assert(segment.FirstFreeChunk == nextInSegment);
segment.FirstFreeChunk = this;
}
if (nextInSegment != null)
{
Debug.Assert(index + size < nextInSegment.Index);
nextInSegment.PrevInSegment = this;
}
InsertIntoSizeList();
}
// the following two methods are dual to each other,
// i.e. one can be transformed into the other by way of simple search & replace
public void MoveAfterSizeHasDecreased()
{
Debug.Assert(Size < PrevInSize.Size);
var prev = PrevInSize;
var next = NextInSize;
if (next != null)
{
next.PrevInSize = prev;
}
else
{
Largest = prev;
}
prev.NextInSize = next;
next = prev;
prev = prev.PrevInSize;
while (prev != null && prev.Size > Size)
{
next = prev;
prev = prev.PrevInSize;
}
NextInSize = next;
next.PrevInSize = this;
PrevInSize = prev;
if (prev != null)
{
prev.NextInSize = this;
}
else
{
Smallest = this;
}
}
public FreeChunk(PoolSegment segment, FreeChunk prevInSegment, FreeChunk nextInSegment, int index, int size) {
Debug.Assert(index >= 0 && size > 0 && index + size <= segment.Size);
Segment = segment;
Index = index;
Size = size;
PrevInSegment = prevInSegment;
NextInSegment = nextInSegment;
if (prevInSegment != null) {
Debug.Assert(prevInSegment.Index + prevInSegment.Size < index);
prevInSegment.NextInSegment = this;
} else {
Debug.Assert(segment.FirstFreeChunk == nextInSegment);
segment.FirstFreeChunk = this;
}
if (nextInSegment != null) {
Debug.Assert(index + size < nextInSegment.Index);
nextInSegment.PrevInSegment = this;
}
InsertIntoSizeList();
}
private void InsertIntoSizeList() {
var largest = FreeChunk.Largest;
if (largest != null) {
if (largest.Size <= Size) {
largest.NextInSize = this;
PrevInSize = largest;
FreeChunk.Largest = this;
} else {
NextInSize = largest;
var prev = largest.PrevInSize;
largest.PrevInSize = this;
if (prev != null) {
PrevInSize = prev;
prev.NextInSize = this;
if (Size < prev.Size) MoveAfterSizeHasDecreased();
} else FreeChunk.Smallest = this;
}
} else {
FreeChunk.Smallest = this;
FreeChunk.Largest = this;
}
}
private void InsertIntoSizeList()
{
var largest = FreeChunk.Largest;
if (largest != null)
{
if (largest.Size <= Size)
{
largest.NextInSize = this;
PrevInSize = largest;
FreeChunk.Largest = this;
}
else
{
NextInSize = largest;
var prev = largest.PrevInSize;
largest.PrevInSize = this;
if (prev != null)
{
PrevInSize = prev;
prev.NextInSize = this;
if (Size < prev.Size)
{
MoveAfterSizeHasDecreased();
}
}
else
{
FreeChunk.Smallest = this;
}
}
}
else
{
FreeChunk.Smallest = this;
FreeChunk.Largest = this;
}
}
public void Remove()
{
var prev = PrevInSegment;
var next = NextInSegment;
if (prev != null)
{
prev.NextInSegment = next;
}
else
{
Segment.FirstFreeChunk = next;
}
if (next != null)
{
next.PrevInSegment = prev;
}
prev = PrevInSize;
next = NextInSize;
if (prev != null)
{
prev.NextInSize = next;
}
else
{
Smallest = next;
}
if (next != null)
{
next.PrevInSize = prev;
}
else
{
Largest = prev;
}
}
public void Dispose()
{
int size = Length;
Length = -1;
if (size > 0)
{
lock (SyncRoot) {
Allocated -= size;
if (size <= MaxSegmentSize)
{
FreeChunk prev = null;
FreeChunk next = Segment.FirstFreeChunk;
while (next != null && Index > next.Index)
{
prev = next;
next = next.NextInSegment;
}
if (prev == null || prev.Index + prev.Size != Index)
{
if (next != null && Index + size == next.Index)
{
next.Index = Index;
next.Size += size;
var nextNext = next.NextInSize;
if (nextNext != null && next.Size > nextNext.Size)
{
next.MoveAfterSizeHasIncreased();
}
}
else
{
new FreeChunk(Segment, prev, next, Index, size); // inserts itself into the lists
}
}
else
{
if (next != null && Index + size == next.Index)
{
prev.Size += size + next.Size;
next.Remove();
}
else
{
prev.Size += size;
}
if (prev.NextInSize != null && prev.Size > prev.NextInSize.Size)
{
prev.MoveAfterSizeHasIncreased();
}
}
Segment.AssertIntegrity();
var first = Segment.FirstFreeChunk;
if (first.Size == Segment.Size && ++NumberOfUnusedSegments > MaxNumberOfUnusedSegments)
{
--NumberOfUnusedSegments;
first.Remove();
Segment.Dispose();
}
}
else // size > MaxSegmentSize
{
Debug.Assert(size == Segment.Size);
Segment.Dispose();
}
}
}
}
public static StringBuffer Create(int minLength)
{
int size = unchecked (minLength + (MinChunkSize - 1));
if (size > (MinChunkSize - 1)) // minLength > 0 && minLength <= System.Int32.MaxValue - (MinChunkSize - 1)
{
size -= (int)((uint)size % (uint)MinChunkSize); // round down to multiple of MinChunkSize
lock (SyncRoot) {
Allocated += size;
FreeChunk chunk = FreeChunk.Largest;
if (chunk != null) // find smallest free chunk that is large enough to hold the buffer
{
if (size > 10 * MinChunkSize)
{
var prev = chunk.PrevInSize;
while (prev != null && prev.Size >= size)
{
chunk = prev;
prev = prev.PrevInSize;
}
}
else
{
chunk = FreeChunk.Smallest;
var next = chunk.NextInSize;
while (chunk.Size < size && next != null)
{
chunk = next;
next = next.NextInSize;
}
}
if (size <= chunk.Size)
{
int index = chunk.Index;
if (index == 0 && chunk.Size == chunk.Segment.Size)
{
--NumberOfUnusedSegments;
}
if (size != chunk.Size)
{
chunk.Index += size;
chunk.Size -= size;
var prev = chunk.PrevInSize;
if (prev != null && chunk.Size < prev.Size)
{
chunk.MoveAfterSizeHasDecreased();
}
}
else
{
chunk.Remove();
}
chunk.Segment.AssertIntegrity();
return(new StringBuffer(chunk.Segment, index, size));
}
}
return(PoolSegment.AllocateStringBufferInNewSegment(size));
}
}
else
{
if (minLength < 0)
{
throw new ArgumentOutOfRangeException("minLength", "minLength is negative.");
}
else if (minLength > 0)
{
throw new ArgumentOutOfRangeException("minLength", "minLength is too large. The maximum string buffer length is approximately 2^30.");
}
return(new StringBuffer(null, 0, 0));
}
}
public void MoveAfterSizeHasIncreased() {
Debug.Assert(Size > NextInSize.Size);
var next = NextInSize;
var prev = PrevInSize;
if (prev != null) prev.NextInSize = next;
else Smallest = next;
next.PrevInSize = prev;
prev = next;
next = next.NextInSize;
while (next != null && next.Size < Size) {
prev = next;
next = next.NextInSize;
}
PrevInSize = prev;
prev.NextInSize = this;
NextInSize = next;
if (next != null) next.PrevInSize = this;
else Largest = this;
}
// the following two methods are dual to each other,
// i.e. one can be transformed into the other by way of simple search & replace
public void MoveAfterSizeHasDecreased() {
Debug.Assert(Size < PrevInSize.Size);
var prev = PrevInSize;
var next = NextInSize;
if (next != null) next.PrevInSize = prev;
else Largest = prev;
prev.NextInSize = next;
next = prev;
prev = prev.PrevInSize;
while (prev != null && prev.Size > Size) {
next = prev;
prev = prev.PrevInSize;
}
NextInSize = next;
next.PrevInSize = this;
PrevInSize = prev;
if (prev != null) prev.NextInSize = this;
else Smallest = this;
}
public void Remove() {
var prev = PrevInSegment;
var next = NextInSegment;
if (prev != null) prev.NextInSegment = next;
else Segment.FirstFreeChunk = next;
if (next != null) next.PrevInSegment = prev;
prev = PrevInSize;
next = NextInSize;
if (prev != null) prev.NextInSize = next;
else Smallest = next;
if (next != null) next.PrevInSize = prev;
else Largest = prev;
}
