Move hashmap.h and hashmap.cc from the 'bin' directory to 'platform' directory so that it can be us…

bin/hashmap.cc

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-#include "bin/hashmap.h"
-
-#include "bin/builtin.h"
-#include "platform/utils.h"
-
-HashMap::HashMap(MatchFun match,
-                 uint32_t initial_capacity) {
-  match_ = match;
-  Initialize(initial_capacity);
-}
-
-
-HashMap::~HashMap() {
-  free(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* candidate = Probe(key, hash);
-  if (candidate->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_);
-
-  // "candidate" is the candidate entry to clear. "next" is used to scan
-  // forwards.
-  Entry* next = candidate;  // Start at the entry to remove.
-  while (true) {
-    // Move "next" to the next entry. Wrap when at the end of the array.
-    next = next + 1;
-    if (next == map_end()) {
-      next = map_;
-    }
-
-    // All entries between "candidate" and "next" have their initial position
-    // between candidate and entry and the entry candidate can be cleared
-    // without breaking the search for these entries.
-    if (next->key == NULL) {
-      break;
-    }
-
-    // Find the initial position for the entry at position "next". That is
-    // the entry where searching for the entry at position "next" will
-    // actually start.
-    Entry* start = map_ + (next->hash & (capacity_ - 1));
-
-    // If the entry at position "next" has its initial position outside the
-    // range between "candidate" and "next" it can be moved forward to
-    // position "candidate" and will still be found. There is now the new
-    // candidate entry for clearing.
-    if ((next > candidate && (start <= candidate || start > next)) ||
-        (next < candidate && (start <= candidate && start > next))) {
-      *candidate = *next;
-      candidate = next;
-    }
-  }
-
-  // Clear the candidate which will not break searching the hash table.
-  candidate->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(dart::Utils::IsPowerOfTwo(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(dart::Utils::IsPowerOfTwo(capacity));
-  map_ = reinterpret_cast<Entry*>(malloc(capacity * sizeof(Entry)));
-  if (map_ == NULL) {
-    // TODO(sgjesse): Handle out of memory.
-    FATAL("Cannot allocate memory for hashmap");
-    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.
-  free(map);
-}