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 #include "bstr.h"
  23
  24 /// \defgroup OptionsStruct Options struct
  25 /// \ingroup Options
  26 /// An API to manipulate structs using m_option.
  27 ///@{
  28
  29 /// \file m_struct.h
  30
  31 struct m_option;
  32
  33 /// Struct definition
  34 typedef struct m_struct_st {
  35   /// For error messages and debugging
  36   const char* name;
  37   /// size of the whole struct
  38   unsigned int size;
  39   /// Pointer to a struct filled with the default settings
  40   const void* defaults;
  41   /// Field list.
  42   /** The p field of the \ref m_option struct must contain the offset
  43    *  of the member in the struct (use M_ST_OFF macro for this).
  44    */
  45   const struct m_option* fields;
  46 } m_struct_t;
  47
  48
  49 // From glib.h (modified ;-)
  50
  51 /// Get the offset of a struct field.
  52 /** \param struct_type Struct type.
  53  *  \param member Name of the field.
  54  *  \return The offset of the field in bytes.
  55  */
  56 #define M_ST_OFF(struct_type, member)    \
  57     ((void*) &((struct_type*) 0)->member)
  58
  59 /// Get a pointer to a struct field.
  60 /** \param struct_p Pointer to the struct.
  61  *  \param struct_offset Offset of the field in the struct.
  62  *  \return Pointer to the struct field.
  63  */
  64 #define M_ST_MB_P(struct_p, struct_offset)   \
  65     ((void *)((char *)(struct_p) + (unsigned long)(struct_offset)))
  66
  67 /// Access a struct field at a given offset.
  68 /** \param member_type Type of the field.
  69  *  \param struct_p Pointer to the struct.
  70  *  \param struct_offset Offset of the field in the struct.
  71  *  \return The struct field at the given offset.
  72  */
  73 #define M_ST_MB(member_type, struct_p, struct_offset)   \
  74     (*(member_type*) M_ST_MB_P ((struct_p), (struct_offset)))
  75
  76
  77
  78 /// Allocate the struct and set it to the defaults.
  79 /** \param st Struct definition.
  80  *  \return The newly allocated object set to default.
  81  */
  82 void*
  83 m_struct_alloc(const m_struct_t* st);
  84
  85 /// Set a field of the struct.
  86 /** \param st Struct definition.
  87  *  \param obj Pointer to the struct to set.
  88  *  \param field Name of the field to set.
  89  *  \param param New value of the field.
  90  *  \return 0 on error, 1 on success.
  91  */
  92 int m_struct_set(const m_struct_t *st, void *obj, const char *field,
  93                  struct bstr param);
  94
  95 /// Reset a field (or all if field == NULL) to defaults.
  96 /** \param st Struct definition.
  97  *  \param obj Pointer to the struct to set.
  98  *  \param field Name of the field to reset, if NULL all fields are reseted.
  99  */
 100 void
 101 m_struct_reset(const m_struct_t* st, void* obj, const char* field);
 102
 103 /// Create a copy of an existing struct.
 104 /** \param st Struct definition.
 105  *  \param obj Pointer to the struct to copy.
 106  *  \return Newly allocated copy of obj.
 107  */
 108 void*
 109 m_struct_copy(const m_struct_t* st, void* obj);
 110
 111 /// Free an allocated struct.
 112 /** \param st Struct definition.
 113  *  \param obj Pointer to the struct to copy.
 114  */
 115 void
 116 m_struct_free(const m_struct_t* st, void* obj);
 117
 118 /// Get a field description.
 119 /** \param st Struct definition.
 120  *  \param f Name of the field.
 121  *  \return The \ref m_option struct describing the field or NULL if not found.
 122  */
 123 const struct m_option*
 124 m_struct_get_field(const m_struct_t* st,const char* f);
 125
 126 ///@}
 127
 128 #endif /* MPLAYER_M_STRUCT_H */