src/driver.h

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD 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.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file driver.h Base for all drivers (video, sound, music, etc). */
  11
  12 #ifndef DRIVER_H
  13 #define DRIVER_H
  14
  15 #include "core/enum_type.hpp"
  16 #include "core/string_compare_type.hpp"
  17 #include <map>
  18
  19 const char *GetDriverParam(const char * const *parm, const char *name);
  20 bool GetDriverParamBool(const char * const *parm, const char *name);
  21 int GetDriverParamInt(const char * const *parm, const char *name, int def);
  22
  23 /** A driver for communicating with the user. */
  24 class Driver {
  25 public:
  26         /**
  27          * Start this driver.
  28          * @param parm Parameters passed to the driver.
  29          * @return NULL if everything went okay, otherwise an error message.
  30          */
  31         virtual const char *Start(const char * const *parm) = 0;
  32
  33         /**
  34          * Stop this driver.
  35          */
  36         virtual void Stop() = 0;
  37
  38         virtual ~Driver() { }
  39
  40         /** The type of driver */
  41         enum Type {
  42                 DT_BEGIN = 0, ///< Helper for iteration
  43                 DT_MUSIC = 0, ///< A music driver, needs to be before sound to properly shut down extmidi forked music players
  44                 DT_SOUND,     ///< A sound driver
  45                 DT_VIDEO,     ///< A video driver
  46                 DT_END,       ///< Helper for iteration
  47         };
  48
  49         /**
  50          * Get the name of this driver.
  51          * @return The name of the driver.
  52          */
  53         virtual const char *GetName() const = 0;
  54 };
  55
  56 DECLARE_POSTFIX_INCREMENT(Driver::Type)
  57
  58
  59 /** Base for all driver factories. */
  60 class DriverFactoryBase {
  61 private:
  62         Driver::Type type;       ///< The type of driver.
  63         int priority;            ///< The priority of this factory.
  64         const char *name;        ///< The name of the drivers of this factory.
  65         const char *description; ///< The description of this driver.
  66
  67         typedef std::map<const char *, DriverFactoryBase *, StringCompare> Drivers; ///< Type for a map of drivers.
  68
  69         /**
  70          * Get the map with drivers.
  71          */
  72         static Drivers &GetDrivers()
  73         {
  74                 static Drivers &s_drivers = *new Drivers();
  75                 return s_drivers;
  76         }
  77
  78         /**
  79          * Get the active driver for the given type.
  80          * @param type The type to get the driver for.
  81          * @return The active driver.
  82          */
  83         static Driver **GetActiveDriver(Driver::Type type)
  84         {
  85                 static Driver *s_driver[3] = { NULL, NULL, NULL };
  86                 return &s_driver[type];
  87         }
  88
  89         /**
  90          * Get the driver type name.
  91          * @param type The type of driver to get the name of.
  92          * @return The name of the type.
  93          */
  94         static const char *GetDriverTypeName(Driver::Type type)
  95         {
  96                 static const char * const driver_type_name[] = { "music", "sound", "video" };
  97                 return driver_type_name[type];
  98         }
  99
 100 protected:
 101         DriverFactoryBase(Driver::Type type, int priority, const char *name, const char *description);
 102
 103         virtual ~DriverFactoryBase();
 104
 105 public:
 106         /**
 107          * Shuts down all active drivers
 108          */
 109         static void ShutdownDrivers()
 110         {
 111                 for (Driver::Type dt = Driver::DT_BEGIN; dt < Driver::DT_END; dt++) {
 112                         Driver *driver = *GetActiveDriver(dt);
 113                         if (driver != NULL) driver->Stop();
 114                 }
 115         }
 116
 117         static Driver *SelectDriver(const char *name, Driver::Type type);
 118         static char *GetDriversInfo(char *p, const char *last);
 119
 120         /**
 121          * Get a nice description of the driver-class.
 122          * @return The description.
 123          */
 124         const char *GetDescription() const
 125         {
 126                 return this->description;
 127         }
 128
 129         /**
 130          * Create an instance of this driver-class.
 131          * @return The instance.
 132          */
 133         virtual Driver *CreateInstance() const = 0;
 134 };
 135
 136 #endif /* DRIVER_H */