diff -r 000000000000 -r 4f2f89ce4247 JavaScriptCore/wtf/TCPageMap.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/wtf/TCPageMap.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,316 @@
+// Copyright (c) 2005, Google Inc.
+// All rights reserved.
+// 
+// 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 Google Inc. 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.
+
+// ---
+// Author: Sanjay Ghemawat <opensource@google.com>
+//
+// A data structure used by the caching malloc.  It maps from page# to
+// a pointer that contains info about that page.  We use two
+// representations: one for 32-bit addresses, and another for 64 bit
+// addresses.  Both representations provide the same interface.  The
+// first representation is implemented as a flat array, the seconds as
+// a three-level radix tree that strips away approximately 1/3rd of
+// the bits every time.
+//
+// The BITS parameter should be the number of bits required to hold
+// a page number.  E.g., with 32 bit pointers and 4K pages (i.e.,
+// page offset fits in lower 12 bits), BITS == 20.
+
+#ifndef TCMALLOC_PAGEMAP_H__
+#define TCMALLOC_PAGEMAP_H__
+
+#if HAVE(STDINT_H)
+#include <stdint.h>
+#elif HAVE(INTTYPES_H)
+#include <inttypes.h>
+#else
+#include <sys/types.h>
+#endif
+
+#include <string.h>
+#include "Assertions.h"
+
+// Single-level array
+template <int BITS>
+class TCMalloc_PageMap1 {
+ private:
+  void** array_;
+
+ public:
+  typedef uintptr_t Number;
+
+  void init(void* (*allocator)(size_t)) {
+    array_ = reinterpret_cast<void**>((*allocator)(sizeof(void*) << BITS));
+    memset(array_, 0, sizeof(void*) << BITS);
+  }
+
+  // Ensure that the map contains initialized entries "x .. x+n-1".
+  // Returns true if successful, false if we could not allocate memory.
+  bool Ensure(Number x, size_t n) {
+    // Nothing to do since flat array was allocate at start
+    return true;
+  }
+
+  void PreallocateMoreMemory() {}
+
+  // REQUIRES "k" is in range "[0,2^BITS-1]".
+  // REQUIRES "k" has been ensured before.
+  //
+  // Return the current value for KEY.  Returns "Value()" if not
+  // yet set.
+  void* get(Number k) const {
+    return array_[k];
+  }
+
+  // REQUIRES "k" is in range "[0,2^BITS-1]".
+  // REQUIRES "k" has been ensured before.
+  //
+  // Sets the value for KEY.
+  void set(Number k, void* v) {
+    array_[k] = v;
+  }
+};
+
+// Two-level radix tree
+template <int BITS>
+class TCMalloc_PageMap2 {
+ private:
+  // Put 32 entries in the root and (2^BITS)/32 entries in each leaf.
+  static const int ROOT_BITS = 5;
+  static const int ROOT_LENGTH = 1 << ROOT_BITS;
+
+  static const int LEAF_BITS = BITS - ROOT_BITS;
+  static const int LEAF_LENGTH = 1 << LEAF_BITS;
+
+  // Leaf node
+  struct Leaf {
+    void* values[LEAF_LENGTH];
+  };
+
+  Leaf* root_[ROOT_LENGTH];             // Pointers to 32 child nodes
+  void* (*allocator_)(size_t);          // Memory allocator
+
+ public:
+  typedef uintptr_t Number;
+
+  void init(void* (*allocator)(size_t)) {
+    allocator_ = allocator;
+    memset(root_, 0, sizeof(root_));
+  }
+
+  void* get(Number k) const {
+    ASSERT(k >> BITS == 0);
+    const Number i1 = k >> LEAF_BITS;
+    const Number i2 = k & (LEAF_LENGTH-1);
+    return root_[i1]->values[i2];
+  }
+
+  void set(Number k, void* v) {
+    ASSERT(k >> BITS == 0);
+    const Number i1 = k >> LEAF_BITS;
+    const Number i2 = k & (LEAF_LENGTH-1);
+    root_[i1]->values[i2] = v;
+  }
+
+  bool Ensure(Number start, size_t n) {
+    for (Number key = start; key <= start + n - 1; ) {
+      const Number i1 = key >> LEAF_BITS;
+
+      // Make 2nd level node if necessary
+      if (root_[i1] == NULL) {
+        Leaf* leaf = reinterpret_cast<Leaf*>((*allocator_)(sizeof(Leaf)));
+        if (leaf == NULL) return false;
+        memset(leaf, 0, sizeof(*leaf));
+        root_[i1] = leaf;
+      }
+
+      // Advance key past whatever is covered by this leaf node
+      key = ((key >> LEAF_BITS) + 1) << LEAF_BITS;
+    }
+    return true;
+  }
+
+  void PreallocateMoreMemory() {
+    // Allocate enough to keep track of all possible pages
+    Ensure(0, 1 << BITS);
+  }
+
+#ifdef WTF_CHANGES
+  template<class Visitor, class MemoryReader>
+  void visitValues(Visitor& visitor, const MemoryReader& reader)
+  {
+    for (int i = 0; i < ROOT_LENGTH; i++) {
+      if (!root_[i])
+        continue;
+
+      Leaf* l = reader(reinterpret_cast<Leaf*>(root_[i]));
+      for (int j = 0; j < LEAF_LENGTH; j += visitor.visit(l->values[j]))
+        ;
+    }
+  }
+
+  template<class Visitor, class MemoryReader>
+  void visitAllocations(Visitor& visitor, const MemoryReader&) {
+    for (int i = 0; i < ROOT_LENGTH; i++) {
+      if (root_[i])
+        visitor.visit(root_[i], sizeof(Leaf));
+    }
+  }
+#endif
+};
+
+// Three-level radix tree
+template <int BITS>
+class TCMalloc_PageMap3 {
+ private:
+  // How many bits should we consume at each interior level
+  static const int INTERIOR_BITS = (BITS + 2) / 3; // Round-up
+  static const int INTERIOR_LENGTH = 1 << INTERIOR_BITS;
+
+  // How many bits should we consume at leaf level
+  static const int LEAF_BITS = BITS - 2*INTERIOR_BITS;
+  static const int LEAF_LENGTH = 1 << LEAF_BITS;
+
+  // Interior node
+  struct Node {
+    Node* ptrs[INTERIOR_LENGTH];
+  };
+
+  // Leaf node
+  struct Leaf {
+    void* values[LEAF_LENGTH];
+  };
+
+  Node* root_;                          // Root of radix tree
+  void* (*allocator_)(size_t);          // Memory allocator
+
+  Node* NewNode() {
+    Node* result = reinterpret_cast<Node*>((*allocator_)(sizeof(Node)));
+    if (result != NULL) {
+      memset(result, 0, sizeof(*result));
+    }
+    return result;
+  }
+
+ public:
+  typedef uintptr_t Number;
+
+  void init(void* (*allocator)(size_t)) {
+    allocator_ = allocator;
+    root_ = NewNode();
+  }
+
+  void* get(Number k) const {
+    ASSERT(k >> BITS == 0);
+    const Number i1 = k >> (LEAF_BITS + INTERIOR_BITS);
+    const Number i2 = (k >> LEAF_BITS) & (INTERIOR_LENGTH-1);
+    const Number i3 = k & (LEAF_LENGTH-1);
+    return reinterpret_cast<Leaf*>(root_->ptrs[i1]->ptrs[i2])->values[i3];
+  }
+
+  void set(Number k, void* v) {
+    ASSERT(k >> BITS == 0);
+    const Number i1 = k >> (LEAF_BITS + INTERIOR_BITS);
+    const Number i2 = (k >> LEAF_BITS) & (INTERIOR_LENGTH-1);
+    const Number i3 = k & (LEAF_LENGTH-1);
+    reinterpret_cast<Leaf*>(root_->ptrs[i1]->ptrs[i2])->values[i3] = v;
+  }
+
+  bool Ensure(Number start, size_t n) {
+    for (Number key = start; key <= start + n - 1; ) {
+      const Number i1 = key >> (LEAF_BITS + INTERIOR_BITS);
+      const Number i2 = (key >> LEAF_BITS) & (INTERIOR_LENGTH-1);
+
+      // Make 2nd level node if necessary
+      if (root_->ptrs[i1] == NULL) {
+        Node* n = NewNode();
+        if (n == NULL) return false;
+        root_->ptrs[i1] = n;
+      }
+
+      // Make leaf node if necessary
+      if (root_->ptrs[i1]->ptrs[i2] == NULL) {
+        Leaf* leaf = reinterpret_cast<Leaf*>((*allocator_)(sizeof(Leaf)));
+        if (leaf == NULL) return false;
+        memset(leaf, 0, sizeof(*leaf));
+        root_->ptrs[i1]->ptrs[i2] = reinterpret_cast<Node*>(leaf);
+      }
+
+      // Advance key past whatever is covered by this leaf node
+      key = ((key >> LEAF_BITS) + 1) << LEAF_BITS;
+    }
+    return true;
+  }
+
+  void PreallocateMoreMemory() {
+  }
+
+#ifdef WTF_CHANGES
+  template<class Visitor, class MemoryReader>
+  void visitValues(Visitor& visitor, const MemoryReader& reader) {
+    Node* root = reader(root_);
+    for (int i = 0; i < INTERIOR_LENGTH; i++) {
+      if (!root->ptrs[i])
+        continue;
+
+      Node* n = reader(root->ptrs[i]);
+      for (int j = 0; j < INTERIOR_LENGTH; j++) {
+        if (!n->ptrs[j])
+          continue;
+
+        Leaf* l = reader(reinterpret_cast<Leaf*>(n->ptrs[j]));
+        for (int k = 0; k < LEAF_LENGTH; k += visitor.visit(l->values[k]))
+          ;
+      }
+    }
+  }
+
+  template<class Visitor, class MemoryReader>
+  void visitAllocations(Visitor& visitor, const MemoryReader& reader) {
+    visitor.visit(root_, sizeof(Node));
+
+    Node* root = reader(root_);
+    for (int i = 0; i < INTERIOR_LENGTH; i++) {
+      if (!root->ptrs[i])
+        continue;
+
+      visitor.visit(root->ptrs[i], sizeof(Node));
+      Node* n = reader(root->ptrs[i]);
+      for (int j = 0; j < INTERIOR_LENGTH; j++) {
+        if (!n->ptrs[j])
+          continue;
+
+        visitor.visit(n->ptrs[j], sizeof(Leaf));
+      }
+    }
+  }
+#endif
+};
+
+#endif  // TCMALLOC_PAGEMAP_H__