Make HashMap a template class to specify the allocation policy.

src/hashmap.cc

Index: src/hashmap.cc
===================================================================
--- src/hashmap.cc	(revision 10795)
+++ src/hashmap.cc	(working copy)
@@ -1,224 +0,0 @@
-// Copyright 2008 the V8 project authors. 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.
-
-#include "../include/v8stdint.h"
-#include "globals.h"
-#include "checks.h"
-#include "utils.h"
-#include "allocation.h"
-
-#include "hashmap.h"
-
-namespace v8 {
-namespace internal {
-
-Allocator* HashMap::DefaultAllocator = ::new Allocator();
-
-
-HashMap::HashMap(MatchFun match,
-                 Allocator* allocator,
-                 uint32_t initial_capacity) {
-  allocator_ = allocator;
-  match_ = match;
-  Initialize(initial_capacity);
-}
-
-
-HashMap::~HashMap() {
-  if (allocator_) {
-    allocator_->Delete(map_);
-  }
-}
-
-
-HashMap::Entry* HashMap::Lookup(void* key, uint32_t hash, bool insert) {
-  // Find a matching entry.
-  Entry* p = Probe(key, hash);
-  if (p->key != NULL) {
-    return p;
-  }
-
-  // No entry found; insert one if necessary.
-  if (insert) {
-    p->key = key;
-    p->value = NULL;
-    p->hash = hash;
-    occupancy_++;
-
-    // Grow the map if we reached >= 80% occupancy.
-    if (occupancy_ + occupancy_/4 >= capacity_) {
-      Resize();
-      p = Probe(key, hash);
-    }
-
-    return p;
-  }
-
-  // No entry found and none inserted.
-  return NULL;
-}
-
-
-void HashMap::Remove(void* key, uint32_t hash) {
-  // Lookup the entry for the key to remove.
-  Entry* p = Probe(key, hash);
-  if (p->key == NULL) {
-    // Key not found nothing to remove.
-    return;
-  }
-
-  // To remove an entry we need to ensure that it does not create an empty
-  // entry that will cause the search for another entry to stop too soon. If all
-  // the entries between the entry to remove and the next empty slot have their
-  // initial position inside this interval, clearing the entry to remove will
-  // not break the search. If, while searching for the next empty entry, an
-  // entry is encountered which does not have its initial position between the
-  // entry to remove and the position looked at, then this entry can be moved to
-  // the place of the entry to remove without breaking the search for it. The
-  // entry made vacant by this move is now the entry to remove and the process
-  // starts over.
-  // Algorithm from http://en.wikipedia.org/wiki/Open_addressing.
-
-  // This guarantees loop termination as there is at least one empty entry so
-  // eventually the removed entry will have an empty entry after it.
-  ASSERT(occupancy_ < capacity_);
-
-  // p is the candidate entry to clear. q is used to scan forwards.
-  Entry* q = p;  // Start at the entry to remove.
-  while (true) {
-    // Move q to the next entry.
-    q = q + 1;
-    if (q == map_end()) {
-      q = map_;
-    }
-
-    // All entries between p and q have their initial position between p and q
-    // and the entry p can be cleared without breaking the search for these
-    // entries.
-    if (q->key == NULL) {
-      break;
-    }
-
-    // Find the initial position for the entry at position q.
-    Entry* r = map_ + (q->hash & (capacity_ - 1));
-
-    // If the entry at position q has its initial position outside the range
-    // between p and q it can be moved forward to position p and will still be
-    // found. There is now a new candidate entry for clearing.
-    if ((q > p && (r <= p || r > q)) ||
-        (q < p && (r <= p && r > q))) {
-      *p = *q;
-      p = q;
-    }
-  }
-
-  // Clear the entry which is allowed to en emptied.
-  p->key = NULL;
-  occupancy_--;
-}
-
-
-void HashMap::Clear() {
-  // Mark all entries as empty.
-  const Entry* end = map_end();
-  for (Entry* p = map_; p < end; p++) {
-    p->key = NULL;
-  }
-  occupancy_ = 0;
-}
-
-
-HashMap::Entry* HashMap::Start() const {
-  return Next(map_ - 1);
-}
-
-
-HashMap::Entry* HashMap::Next(Entry* p) const {
-  const Entry* end = map_end();
-  ASSERT(map_ - 1 <= p && p < end);
-  for (p++; p < end; p++) {
-    if (p->key != NULL) {
-      return p;
-    }
-  }
-  return NULL;
-}
-
-
-HashMap::Entry* HashMap::Probe(void* key, uint32_t hash) {
-  ASSERT(key != NULL);
-
-  ASSERT(IsPowerOf2(capacity_));
-  Entry* p = map_ + (hash & (capacity_ - 1));
-  const Entry* end = map_end();
-  ASSERT(map_ <= p && p < end);
-
-  ASSERT(occupancy_ < capacity_);  // Guarantees loop termination.
-  while (p->key != NULL && (hash != p->hash || !match_(key, p->key))) {
-    p++;
-    if (p >= end) {
-      p = map_;
-    }
-  }
-
-  return p;
-}
-
-
-void HashMap::Initialize(uint32_t capacity) {
-  ASSERT(IsPowerOf2(capacity));
-  map_ = reinterpret_cast<Entry*>(allocator_->New(capacity * sizeof(Entry)));
-  if (map_ == NULL) {
-    v8::internal::FatalProcessOutOfMemory("HashMap::Initialize");
-    return;
-  }
-  capacity_ = capacity;
-  Clear();
-}
-
-
-void HashMap::Resize() {
-  Entry* map = map_;
-  uint32_t n = occupancy_;
-
-  // Allocate larger map.
-  Initialize(capacity_ * 2);
-
-  // Rehash all current entries.
-  for (Entry* p = map; n > 0; p++) {
-    if (p->key != NULL) {
-      Lookup(p->key, p->hash, true)->value = p->value;
-      n--;
-    }
-  }
-
-  // Delete old map.
-  allocator_->Delete(map);
-}
-
-
-} }  // namespace v8::internal