m_struct.h

   1 /*
   2  * This file is part of MPlayer.
   3  *
   4  * MPlayer is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * MPlayer is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #ifndef MPLAYER_M_STRUCT_H
  20 #define MPLAYER_M_STRUCT_H
  21
  22 /// \defgroup OptionsStruct Options struct
  23 /// \ingroup Options
  24 /// An API to manipulate structs using m_option.
  25 ///@{
  26
  27 /// \file m_struct.h
  28
  29 struct m_option;
  30
  31 /// Struct definition
  32 typedef struct m_struct_st {
  33   /// For error messages and debugging
  34   const char* name;
  35   /// size of the whole struct
  36   unsigned int size;
  37   /// Pointer to a struct filled with the default settings
  38   const void* defaults;
  39   /// Field list.
  40   /** The p field of the \ref m_option struct must contain the offset
  41    *  of the member in the struct (use M_ST_OFF macro for this).
  42    */
  43   const struct m_option* fields;
  44 } m_struct_t;
  45
  46
  47 // From glib.h (modified ;-)
  48
  49 /// Get the offset of a struct field.
  50 /** \param struct_type Struct type.
  51  *  \param member Name of the field.
  52  *  \return The offset of the field in bytes.
  53  */
  54 #define M_ST_OFF(struct_type, member)    \
  55     ((void*) &((struct_type*) 0)->member)
  56
  57 /// Get a pointer to a struct field.
  58 /** \param struct_p Pointer to the struct.
  59  *  \param struct_offset Offset of the field in the struct.
  60  *  \return Pointer to the struct field.
  61  */
  62 #define M_ST_MB_P(struct_p, struct_offset)   \
  63     ((void *)((char *)(struct_p) + (unsigned long)(struct_offset)))
  64
  65 /// Access a struct field at a given offset.
  66 /** \param member_type Type of the field.
  67  *  \param struct_p Pointer to the struct.
  68  *  \param struct_offset Offset of the field in the struct.
  69  *  \return The struct field at the given offset.
  70  */
  71 #define M_ST_MB(member_type, struct_p, struct_offset)   \
  72     (*(member_type*) M_ST_MB_P ((struct_p), (struct_offset)))
  73
  74
  75
  76 /// Allocate the struct and set it to the defaults.
  77 /** \param st Struct definition.
  78  *  \return The newly allocated object set to default.
  79  */
  80 void*
  81 m_struct_alloc(const m_struct_t* st);
  82
  83 /// Set a field of the struct.
  84 /** \param st Struct definition.
  85  *  \param obj Pointer to the struct to set.
  86  *  \param field Name of the field to set.
  87  *  \param param New value of the field.
  88  *  \return 0 on error, 1 on success.
  89  */
  90 int
  91 m_struct_set(const m_struct_t* st, void* obj, const char* field, const char* param);
  92
  93 /// Reset a field (or all if field == NULL) to defaults.
  94 /** \param st Struct definition.
  95  *  \param obj Pointer to the struct to set.
  96  *  \param field Name of the field to reset, if NULL all fields are reseted.
  97  */
  98 void
  99 m_struct_reset(const m_struct_t* st, void* obj, const char* field);
 100
 101 /// Create a copy of an existing struct.
 102 /** \param st Struct definition.
 103  *  \param obj Pointer to the struct to copy.
 104  *  \return Newly allocated copy of obj.
 105  */
 106 void*
 107 m_struct_copy(const m_struct_t* st, void* obj);
 108
 109 /// Free an allocated struct.
 110 /** \param st Struct definition.
 111  *  \param obj Pointer to the struct to copy.
 112  */
 113 void
 114 m_struct_free(const m_struct_t* st, void* obj);
 115
 116 /// Get a field description.
 117 /** \param st Struct definition.
 118  *  \param f Name of the field.
 119  *  \return The \ref m_option struct describing the field or NULL if not found.
 120  */
 121 const struct m_option*
 122 m_struct_get_field(const m_struct_t* st,const char* f);
 123
 124 ///@}
 125
 126 #endif /* MPLAYER_M_STRUCT_H */