shootout: move test/bench/shootout from Go distribution here

README is new; everything else is a verbatim copy.

For golang/go#13584.

Change-Id: I425b5f3aab235e4165cec0711a5029edcd1a56c3
Reviewed-on: https://go-review.googlesource.com/18319
Reviewed-by: Ian Lance Taylor <iant@golang.org>

shootout/README

@@ -0,0 +1,4 @@
+This directory holds programs from
+"The Computer Language Benchmarks Game".
+They used to be in the main Go distribution in test/bench/shootout
+but are now only of historical value.

shootout/binary-tree-freelist.go

@@ -0,0 +1,129 @@
+/*
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+    * Neither the name of "The Computer Language Benchmarks Game" nor the
+    name of "The Computer Language Shootout Benchmarks" nor the names of
+    its contributors may be used to endorse or promote products derived
+    from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* The Computer Language Benchmarks Game
+ * http://shootout.alioth.debian.org/
+ *
+ * contributed by The Go Authors.
+ * based on C program by Kevin Carson
+ */
+
+package main
+
+import (
+	"flag"
+	"fmt"
+)
+
+var n = flag.Int("n", 15, "depth")
+
+type Node struct {
+	item        int
+	left, right *Node
+}
+
+type Arena struct {
+	head *Node
+}
+
+var arena Arena
+
+func (n *Node) free() {
+	if n.left != nil {
+		n.left.free()
+	}
+	if n.right != nil {
+		n.right.free()
+	}
+	n.left = arena.head
+	arena.head = n
+}
+
+func (a *Arena) New(item int, left, right *Node) *Node {
+	if a.head == nil {
+		nodes := make([]Node, 3<<uint(*n))
+		for i := 0; i < len(nodes)-1; i++ {
+			nodes[i].left = &nodes[i+1]
+		}
+		a.head = &nodes[0]
+	}
+	n := a.head
+	a.head = a.head.left
+	n.item = item
+	n.left = left
+	n.right = right
+	return n
+}
+
+func bottomUpTree(item, depth int) *Node {
+	if depth <= 0 {
+		return arena.New(item, nil, nil)
+	}
+	return arena.New(item, bottomUpTree(2*item-1, depth-1), bottomUpTree(2*item, depth-1))
+}
+
+func (n *Node) itemCheck() int {
+	if n.left == nil {
+		return n.item
+	}
+	return n.item + n.left.itemCheck() - n.right.itemCheck()
+}
+
+const minDepth = 4
+
+func main() {
+	flag.Parse()
+
+	maxDepth := *n
+	if minDepth+2 > *n {
+		maxDepth = minDepth + 2
+	}
+	stretchDepth := maxDepth + 1
+
+	check := bottomUpTree(0, stretchDepth).itemCheck()
+	fmt.Printf("stretch tree of depth %d\t check: %d\n", stretchDepth, check)
+
+	longLivedTree := bottomUpTree(0, maxDepth)
+
+	for depth := minDepth; depth <= maxDepth; depth += 2 {
+		iterations := 1 << uint(maxDepth-depth+minDepth)
+		check = 0
+
+		for i := 1; i <= iterations; i++ {
+			t := bottomUpTree(i, depth)
+			check += t.itemCheck()
+			t.free()
+			t = bottomUpTree(-i, depth)
+			check += t.itemCheck()
+			t.free()
+		}
+		fmt.Printf("%d\t trees of depth %d\t check: %d\n", iterations*2, depth, check)
+	}
+	fmt.Printf("long lived tree of depth %d\t check: %d\n", maxDepth, longLivedTree.itemCheck())
+}

shootout/binary-tree-freelist.txt

@@ -0,0 +1,8 @@
+stretch tree of depth 16	 check: -1
+65536	 trees of depth 4	 check: -65536
+16384	 trees of depth 6	 check: -16384
+4096	 trees of depth 8	 check: -4096
+1024	 trees of depth 10	 check: -1024
+256	 trees of depth 12	 check: -256
+64	 trees of depth 14	 check: -64
+long lived tree of depth 15	 check: -1

shootout/binary-tree.c

@@ -0,0 +1,164 @@
+/*
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+    * Neither the name of "The Computer Language Benchmarks Game" nor the
+    name of "The Computer Language Shootout Benchmarks" nor the names of
+    its contributors may be used to endorse or promote products derived
+    from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* The Computer Language Shootout Benchmarks
+   http://shootout.alioth.debian.org/
+
+   contributed by Kevin Carson
+   compilation:
+       gcc -O3 -fomit-frame-pointer -funroll-loops -static binary-trees.c -lm
+       icc -O3 -ip -unroll -static binary-trees.c -lm
+*/
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+
+typedef struct tn {
+    struct tn*    left;
+    struct tn*    right;
+    long          item;
+} treeNode;
+
+
+treeNode* NewTreeNode(treeNode* left, treeNode* right, long item)
+{
+    treeNode*    new;
+
+    new = (treeNode*)malloc(sizeof(treeNode));
+
+    new->left = left;
+    new->right = right;
+    new->item = item;
+
+    return new;
+} /* NewTreeNode() */
+
+
+long ItemCheck(treeNode* tree)
+{
+    if (tree->left == NULL)
+        return tree->item;
+    else
+        return tree->item + ItemCheck(tree->left) - ItemCheck(tree->right);
+} /* ItemCheck() */
+
+
+treeNode* BottomUpTree(long item, unsigned depth)
+{
+    if (depth > 0)
+        return NewTreeNode
+        (
+            BottomUpTree(2 * item - 1, depth - 1),
+            BottomUpTree(2 * item, depth - 1),
+            item
+        );
+    else
+        return NewTreeNode(NULL, NULL, item);
+} /* BottomUpTree() */
+
+
+void DeleteTree(treeNode* tree)
+{
+    if (tree->left != NULL)
+    {
+        DeleteTree(tree->left);
+        DeleteTree(tree->right);
+    }
+
+    free(tree);
+} /* DeleteTree() */
+
+
+int main(int argc, char* argv[])
+{
+    unsigned   N, depth, minDepth, maxDepth, stretchDepth;
+    treeNode   *stretchTree, *longLivedTree, *tempTree;
+
+    N = atol(argv[1]);
+
+    minDepth = 4;
+
+    if ((minDepth + 2) > N)
+        maxDepth = minDepth + 2;
+    else
+        maxDepth = N;
+
+    stretchDepth = maxDepth + 1;
+
+    stretchTree = BottomUpTree(0, stretchDepth);
+    printf
+    (
+        "stretch tree of depth %u\t check: %li\n",
+        stretchDepth,
+        ItemCheck(stretchTree)
+    );
+
+    DeleteTree(stretchTree);
+
+    longLivedTree = BottomUpTree(0, maxDepth);
+
+    for (depth = minDepth; depth <= maxDepth; depth += 2)
+    {
+        long    i, iterations, check;
+
+        iterations = pow(2, maxDepth - depth + minDepth);
+
+        check = 0;
+
+        for (i = 1; i <= iterations; i++)
+        {
+            tempTree = BottomUpTree(i, depth);
+            check += ItemCheck(tempTree);
+            DeleteTree(tempTree);
+
+            tempTree = BottomUpTree(-i, depth);
+            check += ItemCheck(tempTree);
+            DeleteTree(tempTree);
+        } /* for(i = 1...) */
+
+        printf
+        (
+            "%li\t trees of depth %u\t check: %li\n",
+            iterations * 2,
+            depth,
+            check
+        );
+    } /* for(depth = minDepth...) */
+
+    printf
+    (
+        "long lived tree of depth %u\t check: %li\n",
+        maxDepth,
+        ItemCheck(longLivedTree)
+    );
+
+    return 0;
+} /* main() */