nuclex-shared-dotnet/Nuclex.Support
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The deque's RemoveAt() method now shifts the objects in the direction that produces the least amount of work

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git-svn-id: file:///srv/devel/repo-conversion/nusu@161 d2e56fa2-650e-0410-a79f-9358c0239efd
This commit is contained in:
Markus Ewald 2009-07-13 20:22:59 +00:00
parent 58c3254260
commit 7885e86836
2 changed files with 31 additions and 25 deletions
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55
Source/Collections/Deque.Removal.cs
View File

@ -12,7 +12,9 @@ namespace Nuclex.Support.Collections {
throw new InvalidOperationException("Cannot remove items from empty deque");
}
// TODO: Zero removed array entry if array is kept
// This is necessary to make sure the deque doesn't hold dead objects alive
// in unreachable spaces of its memory.
this.blocks[0][this.firstBlockStartIndex] = default(ItemType);
++this.firstBlockStartIndex;
if(this.firstBlockStartIndex >= this.blockSize) { // Block became empty
@ -33,12 +35,15 @@ namespace Nuclex.Support.Collections {
throw new InvalidOperationException("Cannot remove items from empty deque");
}
// TODO: Zero removed array entry if array is kept
// This is necessary to make sure the deque doesn't hold dead objects alive
// in unreachable spaces of its memory.
int lastBlock = this.blocks.Count - 1;
this.blocks[lastBlock][this.lastBlockEndIndex - 1] = default(ItemType);
--this.lastBlockEndIndex;
if(this.lastBlockEndIndex == 0) { // Block became empty
if(this.count > 1) {
this.blocks.RemoveAt(this.blocks.Count - 1);
this.blocks.RemoveAt(lastBlock);
this.lastBlockEndIndex = this.blockSize;
} else { // Last block - do not remove
this.firstBlockStartIndex = 0;
@ -65,49 +70,49 @@ namespace Nuclex.Support.Collections {
/// </summary>
/// <param name="index">Index of the item that will be removed</param>
private void removeFromLeft(int index) {
if(index == this.count - 1) {
RemoveLast();
if(index == 0) {
RemoveFirst();
} else {
int blockIndex, subIndex;
findIndex(index, out blockIndex, out subIndex);
int lastBlock = this.blocks.Count - 1;
int startIndex;
int firstBlock = 0;
int endIndex;
if(blockIndex < lastBlock) {
if(blockIndex > firstBlock) {
Array.Copy(
this.blocks[blockIndex], subIndex + 1,
this.blocks[blockIndex], subIndex,
this.blockSize - subIndex - 1
this.blocks[blockIndex], 0,
this.blocks[blockIndex], 1,
subIndex
);
this.blocks[blockIndex][this.blockSize - 1] = this.blocks[blockIndex + 1][0];
this.blocks[blockIndex][0] = this.blocks[blockIndex - 1][this.blockSize - 1];
for(int tempIndex = blockIndex + 1; tempIndex < lastBlock; ++tempIndex) {
for(int tempIndex = blockIndex - 1; tempIndex > firstBlock; --tempIndex) {
Array.Copy(
this.blocks[tempIndex], 1,
this.blocks[tempIndex], 0,
this.blocks[tempIndex], 1,
this.blockSize - 1
);
this.blocks[tempIndex][this.blockSize - 1] = this.blocks[tempIndex + 1][0];
this.blocks[tempIndex][0] = this.blocks[tempIndex - 1][this.blockSize - 1];
}
startIndex = 0;
endIndex = this.blockSize - 1;
} else {
startIndex = subIndex;
endIndex = subIndex;
}
Array.Copy(
this.blocks[lastBlock], startIndex + 1,
this.blocks[lastBlock], startIndex,
this.lastBlockEndIndex - startIndex - 1
this.blocks[firstBlock], this.firstBlockStartIndex,
this.blocks[firstBlock], this.firstBlockStartIndex + 1,
endIndex - this.firstBlockStartIndex
);
if(this.lastBlockEndIndex == 1) {
this.blocks.RemoveAt(lastBlock);
this.lastBlockEndIndex = this.blockSize;
if(this.firstBlockStartIndex == this.blockSize - 1) {
this.blocks.RemoveAt(0);
this.firstBlockStartIndex = 0;
} else {
this.blocks[lastBlock][this.lastBlockEndIndex - 1] = default(ItemType);
--this.lastBlockEndIndex;
this.blocks[0][this.firstBlockStartIndex] = default(ItemType);
++this.firstBlockStartIndex;
}
--this.count;

1
Source/Collections/Deque.cs
View File

@ -126,6 +126,7 @@ namespace Nuclex.Support.Collections {
} else {
return (index - this.firstBlockStartIndex + lastBlock * this.blockSize);
}
}
}