gtkradiant/libs/string/pooledstring.h

#if !defined(INCLUDED_POOLEDSTRING_H)
#define INCLUDED_POOLEDSTRING_H

#include <map>
#include "generic/static.h"
#include "string/string.h"
#include "container/hashtable.h"
#include "container/hashfunc.h"

/// \brief The string pool class.
class StringPool : public HashTable<char*, std::size_t, RawStringHash, RawStringEqual>
{
};

inline void StringPool_analyse(StringPool& pool)
{
  typedef std::multimap<std::size_t, const char*> Ordered;
  Ordered ordered;
  std::size_t total = 0;
  std::size_t pooled = 0;
  for(StringPool::iterator i = pool.begin(); i != pool.end(); ++i)
  {
    std::size_t size =  string_length((*i).key) + 1;
    total += size * (*i).value;
    pooled += size + 20;
    ordered.insert(Ordered::value_type((*i).value, (*i).key));
  }
  globalOutputStream() << "total: " << Unsigned(total) << " pooled:" << Unsigned(pooled) << "\n";
  for(Ordered::iterator i = ordered.begin(); i != ordered.end(); ++i)
  {
    globalOutputStream() << (*i).second << " " << Unsigned((*i).first) << "\n";
  }
}


/// \brief A string which can be copied with zero memory cost and minimal runtime cost.
///
/// \param PoolContext The string pool context to use.
template<typename PoolContext>
class PooledString
{
  StringPool::iterator m_i;
  static StringPool::iterator increment(StringPool::iterator i)
  {
    ++(*i).value;
    return i;
  }
  static StringPool::iterator insert(const char* string)
  {
    StringPool::iterator i = PoolContext::instance().find(const_cast<char*>(string));
    if(i == PoolContext::instance().end())
    {
      return PoolContext::instance().insert(string_clone(string), 1);
    }
    return increment(i);
  }
  static void erase(StringPool::iterator i)
  {
    if(--(*i).value == 0)
    {
      char* string = (*i).key;
      PoolContext::instance().erase(i);
      string_release(string, string_length(string));
    }
  }
public:
  PooledString() : m_i(insert(""))
  {
  }
  PooledString(const PooledString& other) : m_i(increment(other.m_i))
  {
  }
  PooledString(const char* string) : m_i(insert(string))
  {
  }
  ~PooledString()
  {
    erase(m_i);
  }
  PooledString& operator=(const PooledString& other)
  {
    PooledString tmp(other);
    tmp.swap(*this);
    return *this;
  }
  PooledString& operator=(const char* string)
  {
    PooledString tmp(string);
    tmp.swap(*this);
    return *this;
  }
  void swap(PooledString& other)
  {
    std::swap(m_i, other.m_i);
  }
  bool operator==(const PooledString& other) const
  {
    return m_i == other.m_i;
  }
  const char* c_str() const
  {
    return (*m_i).key;
  }
};


#endif