libtntdb-dev 1.3-4 / usr / include / tntdb / bits / value.h

/*
 * Copyright (C) 2005,2010 Tommi Maekitalo
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * As a special exception, you may use this file as part of a free
 * software library without restriction. Specifically, if other files
 * instantiate templates or use macros or inline functions from this
 * file, or you compile this file and link it with other files to
 * produce an executable, this file does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License. This exception does not however invalidate any other
 * reasons why the executable file might be covered by the GNU Library
 * General Public License.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef TNTDB_BITS_VALUE_H
#define TNTDB_BITS_VALUE_H

#include <tntdb/iface/ivalue.h>
#include <tntdb/date.h>
#include <tntdb/time.h>
#include <tntdb/datetime.h>
#include <tntdb/decimal.h>
#include <tntdb/blob.h>
#include <tntdb/config.h>
#include <cxxtools/smartptr.h>

namespace tntdb
{
  /**
   * The class Value represents a value, which is fetched from the database.
   */
  class Value
  {
      cxxtools::SmartPtr<IValue> value;

    public:
      explicit Value(IValue* value = 0)
        : value(value)
        { }

      //@{
      /**
       * Explicit data-access.
       * The getXXX-methods return the value in the requested type.
       * If the value can't be converted to the requested type, a exception of
       * type tntdb::TypeError is thrown.
       */
      /// return true, when value is null
      bool isNull() const                 { return !value || value->isNull(); }
      /// return true, when value represents boolean true.
      bool getBool() const                { return value->getBool(); }
      /// tries to convert value into an short.
      short getShort() const              { return value->getShort(); }
      /// tries to convert value into an int.
      int getInt() const                  { return value->getInt(); }
      /// tries to convert value into an long.
      long getLong() const                { return value->getLong(); }
      /// tries to convert value into an unsigned short.
      unsigned short getUnsignedShort() const { return value->getUnsignedShort(); }
      /// tries to convert value into an unsigned.
      unsigned getUnsigned() const        { return value->getUnsigned(); }
      /// tries to convert value into an unsigned long.
      unsigned long getUnsignedLong() const { return value->getUnsignedLong(); }
      /// tries to convert value into an int32_t.
      int32_t getInt32() const            { return value->getInt32(); }
      /// tries to convert value into an uint32_t.
      uint32_t getUnsigned32() const      { return value->getUnsigned32(); }
      /// tries to convert value into an int64_t.
      int64_t getInt64() const            { return value->getInt64(); }
      /// tries to convert value into an uint64_t.
      uint64_t getUnsigned64() const      { return value->getUnsigned64(); }
      /// tries to convert value into a Decimal.
      Decimal getDecimal() const          { return value->getDecimal(); }
      /// tries to convert value into an float.
      float getFloat() const              { return value->getFloat(); }
      /// tries to convert value into an double.
      double getDouble() const            { return value->getDouble(); }
      /// returns the first character of the text-representation.
      char getChar() const                { return value->getChar(); }
      /// returns the value as a string.
      std::string getString() const
        { std::string ret; value->getString(ret); return ret; }
      /// fills the passed string with the value.
      /// this might be slightly more efficient than just returning a new
      /// string since one copy is saved.
      void getString(std::string& ret) const
        { value->getString(ret); }
      /// returns the value as a unicode string.
      cxxtools::String getUString() const
        { cxxtools::String ret; value->getUString(ret); return ret; }
      void getUString(cxxtools::String& ret) const
        { value->getUString(ret); }
      /// Returns the value as a blob.
      /// This is more or less an alias to getString just to stress, that
      /// the data is truly binary and not some text value.
      Blob getBlob() const
        { Blob ret; value->getBlob(ret); return ret; }
      /// Returns the value as a blob.
      void getBlob(Blob& blob) const
        { value->getBlob(blob); }
      /// returns the value as a Date.
      Date getDate() const                { return value->getDate(); }
      /// returns the value as a Time.
      Time getTime() const                { return value->getTime(); }
      /// returns the value as a Datetime.
      Datetime getDatetime() const        { return value->getDatetime(); }
      //@}

      /**
       * Explicit data-access.
       * The get-template return false if the value is null. Otherwise the
       * passed reference is filled with the value.
       * If the value can't be converted to the requested type, a exception of
       * type tntdb::TypeError is thrown.
       *
       * In contrast to the getXXX-methods the type is not specified explictely
       * but determined by the passed reference.
       *
       * The extraction is actually done using the operator>> with a l-value of
       * const Value& and a r-value of a reference to the actual type. This
       * operator is defined for standard types and may be defined for user
       * defined types.
       */
      template <typename T>
      bool getValue(T& ret) const
        { return *this >> ret; }

      /// Shorter name for getValue.
      template <typename T>
      bool get(T& ret) const
        { return *this >> ret; }

      /// Returns true, if this class is not connected to a actual statement.
      bool operator!() const              { return !value; }
      ///  Returns the actual implementation-class.
      const IValue* getImpl() const       { return &*value; }
  };

  //@{
  /**
    Extraction operators for standard types.
   */
  inline bool operator>> (const Value& value, bool& out)
  {
    if (value.isNull())
      return false;

    out = value.getBool();
    return true;
  }

  inline bool operator>> (const Value& value, short& out)
  {
    if (value.isNull())
      return false;

    out = value.getShort();
    return true;
  }

  inline bool operator>> (const Value& value, int& out)
  {
    if (value.isNull())
      return false;

    out = value.getInt();
    return true;
  }

  inline bool operator>> (const Value& value, long& out)
  {
    if (value.isNull())
      return false;

    out = value.getLong();
    return true;
  }

  inline bool operator>> (const Value& value, unsigned short& out)
  {
    if (value.isNull())
      return false;

    out = value.getUnsignedShort();
    return true;
  }

  inline bool operator>> (const Value& value, unsigned& out)
  {
    if (value.isNull())
      return false;

    out = value.getUnsigned();
    return true;
  }

  inline bool operator>> (const Value& value, unsigned long& out)
  {
    if (value.isNull())
      return false;

    out = value.getUnsignedLong();
    return true;
  }

#if INT_INT32_T_CONFLICT != 1
  inline bool operator>> (const Value& value, int32_t& out)
  {
    if (value.isNull())
      return false;

    out = value.getInt32();
    return true;
  }
#endif

#if UNSIGNED_UINT32_T_CONFLICT != 1
  inline bool operator>> (const Value& value, uint32_t& out)
  {
    if (value.isNull())
      return false;

    out = value.getUnsigned32();
    return true;
  }
#endif

#if INT_INT64_T_CONFLICT != 1
  inline bool operator>> (const Value& value, int64_t& out)
  {
    if (value.isNull())
      return false;

    out = value.getInt64();
    return true;
  }
#endif

#if UNSIGNED_UINT64_T_CONFLICT != 1
  inline bool operator>> (const Value& value, uint64_t& out)
  {
    if (value.isNull())
      return false;

    out = value.getUnsigned64();
    return true;
  }
#endif

  inline bool operator>> (const Value& value, Decimal& out)
  {
    if (value.isNull())
      return false;

    out = value.getDecimal();
    return true;
  }

  inline bool operator>> (const Value& value, float& out)
  {
    if (value.isNull())
      return false;

    out = value.getFloat();
    return true;
  }

  inline bool operator>> (const Value& value, double& out)
  {
    if (value.isNull())
      return false;

    out = value.getDouble();
    return true;
  }

  inline bool operator>> (const Value& value, char& out)
  {
    if (value.isNull())
      return false;

    out = value.getChar();
    return true;
  }

  inline bool operator>> (const Value& value, std::string& out)
  {
    if (value.isNull())
      return false;

    value.getString(out);
    return true;
  }

  inline bool operator>> (const Value& value, cxxtools::String& out)
  {
    if (value.isNull())
      return false;

    value.getUString(out);
    return true;
  }

  inline bool operator>> (const Value& value, Blob& out)
  {
    if (value.isNull())
      return false;

    value.getBlob(out);
    return true;
  }

  inline bool operator>> (const Value& value, Date& out)
  {
    if (value.isNull())
      return false;

    out = value.getDate();
    return true;
  }

  inline bool operator>> (const Value& value, Time& out)
  {
    if (value.isNull())
      return false;

    out = value.getTime();
    return true;
  }

  inline bool operator>> (const Value& value, Datetime& out)
  {
    if (value.isNull())
      return false;

    out = value.getDatetime();
    return true;
  }
  //@}

}

#endif // TNTDB_BITS_VALUE_H