Merge pull request #33 from gsvgit/BlockResizeArray

Block resize array basic implementation

src/FSharpx.Collections.Experimental/BlockResizeArray.fs

@@ -0,0 +1,46 @@
+namespace FSharpx.Collections
+
+// Resize array fith fixed size block memory allocation.
+// Provide more optimal space usage for huge arrays than standard ResizeArray.
+// Basic version created by Avdyukhin Dmitry <dimonbv@gmail.com>
+
+type BlockResizeArray<'T> () =
+    let initArraysCount = 1
+    let mutable count = 0
+    let shift = 17
+    let blockSize = 1 <<< shift
+    let smallPart = blockSize - 1
+    let mutable arrays =    Array.init initArraysCount (fun _ -> Array.zeroCreate blockSize)
+    let mutable cap = blockSize * arrays.Length
+    let mutable nextAllocate = cap
+    member this.Add (x : 'T) =
+        if count = nextAllocate then
+            if count = cap then
+                let oldArrays = arrays
+                arrays <- Array.zeroCreate (arrays.Length * 2)
+                for i = 0 to oldArrays.Length-1 do
+                    arrays.[i] <- oldArrays.[i]
+                cap <- blockSize * arrays.Length
+            arrays.[count >>> shift] <- Array.zeroCreate blockSize
+            nextAllocate <- nextAllocate + blockSize
+        arrays.[count >>> shift].[count &&& smallPart] <- x
+        count <- count + 1
+
+    member this.Item i =
+        arrays.[i >>> shift].[i &&& smallPart]
+
+    member this.Set i value =
+        arrays.[i >>> shift].[i &&& smallPart] <- value
+
+    member this.DeleteBlock i = arrays.[i] <- null
+    member this.Count = count
+    member this.Shift = shift
+
+    member this.ToArray() =
+        let res = Array.zeroCreate count
+        for i = 0 to (count >>> shift) - 1 do
+            Array.blit arrays.[i] 0 res (i <<< shift) blockSize
+        if (count &&& smallPart) <> 0 then
+            let i = count >>> shift
+            Array.blit arrays.[i] 0 res (i <<< shift) (count &&& smallPart)
+        res

src/FSharpx.Collections.Experimental/FSharpx.Collections.Experimental.fsproj

@@ -158,6 +158,7 @@
     <Compile Include="SkewBinaryRandomAccessList.fs" />
     <Compile Include="TimeSeries.fs" />
     <Compile Include="CSharpCompat.fs" />
+    <Compile Include="BlockResizeArray.fs" />
     <None Include="paket.template" />
   </ItemGroup>
   <ItemGroup>

tests/FSharpx.Collections.Experimental.Tests/BlockResizeArrayTest.fs

@@ -0,0 +1,48 @@
+module FSharpx.Collections.Experimental.Tests.BlockResizeArrayTest
+
+open FSharpx.Collections
+open NUnit.Framework
+open FsUnit
+open FSharpx.Collections.TimeMeasurement
+
+let arraySize = 2048*2048*10
+let testIters = 10
+let x = 1000UL
+
+[<Test>]
+let ``allocation performance`` () =
+
+    averageTime testIters "ResizeArrayAlloc" (fun () -> 
+        let a = new ResizeArray<uint64>()
+        for i in 0..arraySize do a.Add x )    
+    averageTime testIters "BlockResizeArrayAlloc" (fun () -> 
+        let a = new BlockResizeArray<uint64>()
+        for i in 0..arraySize do a.Add x )  
+
+[<Test>]
+let ``random access performance`` () =
+    let rand = System.Random()
+    let access = [|for i in 0..arraySize-1 -> rand.Next(0, arraySize - 1)|]
+    let a = Array.init arraySize  (fun _ -> x)
+    let ra = new ResizeArray<uint64>()
+    for i in 0..arraySize do ra.Add x
+    let bra = new BlockResizeArray<uint64>()
+    for i in 0..arraySize do bra.Add x
+    let b = ref 0UL
+    averageTime testIters "ResizeArray random access" (fun () -> for i in access do ra.[i] <- 0UL) 
+    averageTime testIters "Array random access" (fun () -> for i in access do a.[i] <- 0UL)       
+    averageTime testIters "BlockResizeArray random access" (fun () -> for i in access do bra.Set i 0UL)
+
+[<Test>]
+let ``sequential access performance`` () =
+    let rand = System.Random()
+    let access = [|0..arraySize-1|]
+    let a = Array.init arraySize  (fun _ -> x)
+    let ra = new ResizeArray<uint64>()
+    for i in 0..arraySize do ra.Add x
+    let bra = new BlockResizeArray<uint64>()
+    for i in 0..arraySize do bra.Add x
+    let b = ref 0UL
+    averageTime testIters "ResizeArray sequential access" (fun () -> for i in access do ra.[i] <- 0UL)    
+    averageTime testIters "Array sequential access" (fun () -> for i in access do a.[i] <- 0UL)    
+    averageTime testIters "BlockResize sequential access" (fun () -> for i in access do bra.Set i 0UL)

tests/FSharpx.Collections.Experimental.Tests/FSharpx.Collections.Experimental.Tests.fsproj

@@ -104,6 +104,7 @@
     <Compile Include="RealTimeQueueTest.fs" />
     <Compile Include="RoseTreeTest.fs" />
     <Compile Include="TimeSeriesTest.fs" />
+    <Compile Include="BlockResizeArrayTest.fs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\FSharpx.Collections.Experimental\FSharpx.Collections.Experimental.fsproj">