symbol_table.h

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/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http:///www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef PAGESPEED_KERNEL_BASE_SYMBOL_TABLE_H_
#define PAGESPEED_KERNEL_BASE_SYMBOL_TABLE_H_

#include <cstddef>
#include <list>
#include <vector>

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/atom.h"
#include "pagespeed/kernel/base/string_hash.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/base/dense_hash_map.h"

namespace net_instaweb {

template<class CharTransform> class SymbolTable {
 public:
  SymbolTable();
  ~SymbolTable() { Clear(); }

  void Clear();

  Atom Intern(const StringPiece& src);

  size_t string_bytes_allocated() const { return string_bytes_allocated_; }

 private:
  struct Comparator {
    bool operator()(const StringPiece& key_a, const StringPiece& key_b) const {
      if (key_a.length() == key_b.length()) {
        const char* a = key_a.data();
        const char* b = key_b.data();
        const char* a_end = a + key_a.length();
        while (a < a_end) {
          if (CharTransform::Normalize(*a) != CharTransform::Normalize(*b)) {
            return false;
          }
          ++a;
          ++b;
        }
        return true;
      } else {
        return false;
      }
    }
  };

  struct Hash {
    size_t operator()(const StringPiece& key) const {
      return HashString<CharTransform, size_t>(key.data(), key.length());
    }
  };

  typedef dense_hash_map<StringPiece, StringPiece*,
                         Hash, Comparator> SymbolMap;
  SymbolMap string_map_;

  std::list<StringPiece> pieces_;

  inline void NewStorage();

  std::vector<char*> storage_;
  char* next_ptr_; 
  size_t string_bytes_allocated_;

  
};

typedef SymbolTable<CaseFold> SymbolTableInsensitive;
typedef SymbolTable<CasePreserve> SymbolTableSensitive;

}  

#endif