dist/pdisk/media.h

   1 /*
   2  * media.h -
   3  *
   4  * Written by Eryk Vershen
   5  */
   6
   7 /*
   8  * Copyright 1997,1998 by Apple Computer, Inc.
   9  *              All Rights Reserved
  10  *
  11  * Permission to use, copy, modify, and distribute this software and
  12  * its documentation for any purpose and without fee is hereby granted,
  13  * provided that the above copyright notice appears in all copies and
  14  * that both the copyright notice and this permission notice appear in
  15  * supporting documentation.
  16  *
  17  * APPLE COMPUTER DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
  18  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  19  * FOR A PARTICULAR PURPOSE.
  20  *
  21  * IN NO EVENT SHALL APPLE COMPUTER BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
  22  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  23  * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
  24  * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  25  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  26  */
  27
  28 #ifndef __media__
  29 #define __media__
  30
  31
  32 /*
  33  * Media is an abstraction of a disk device.
  34  *
  35  * A media object has the following visible attributes:
  36  *
  37  *      a granularity       (e.g. 512, 1024, 1, etc.)
  38  *      a total size in bytes
  39  *
  40  *  And the following operations are available:
  41  *
  42  *      open
  43  *      read @ byte offset for size in bytes
  44  *      write @ byte offset for size in bytes
  45  *      close
  46  *
  47  * XXX Should really split public media interface from "protected" interface.
  48  */
  49
  50
  51 /*
  52  * Defines
  53  */
  54
  55
  56 /*
  57  * Types
  58  */
  59 /* those whose use media objects need just the pointer type */
  60 typedef struct media *MEDIA;
  61
  62 /* those who define media objects need the struct and internal routine types */
  63 typedef long (*media_read)(MEDIA m, long long offset, unsigned long count, void *address);
  64 typedef long (*media_write)(MEDIA m, long long offset, unsigned long count, void *address);
  65 typedef long (*media_close)(MEDIA m);
  66 typedef long (*media_os_reload)(MEDIA m);
  67
  68 struct media {
  69     long            kind;           /* kind of media - SCSI, IDE, etc. */
  70     unsigned long   grain;          /* granularity (offset & size) */
  71     long long       size_in_bytes;  /* offset granularity */
  72     media_read      do_read;        /* device specific routines */
  73     media_write     do_write;
  74     media_close     do_close;
  75     media_os_reload do_os_reload;
  76                                     /* specific media kinds will add extra info */
  77 };
  78
  79 /* those whose use media object iterators need just the pointer type */
  80 typedef struct media_iterator *MEDIA_ITERATOR;
  81
  82 /* those who define media object iterators need the struct and internal routine types */
  83 typedef void (*media_iterator_reset)(MEDIA_ITERATOR m);
  84 typedef char* (*media_iterator_step)(MEDIA_ITERATOR m);
  85 typedef void (*media_iterator_delete)(MEDIA_ITERATOR m);
  86
  87 typedef enum {
  88     kInit,
  89     kReset,
  90     kIterating,
  91     kEnd
  92 } media_iterator_state;
  93
  94 struct media_iterator {
  95     long                    kind;           /* kind of media - SCSI, IDE, etc. */
  96     media_iterator_state    state;          /* init, reset, iterating, at_end */
  97     media_iterator_reset    do_reset;       /* device specific routines */
  98     media_iterator_step     do_step;
  99     media_iterator_delete   do_delete;
 100                                             /* specific media kinds will add extra info */
 101 };
 102
 103
 104 /*
 105  * Global Constants
 106  */
 107
 108
 109 /*
 110  * Global Variables
 111  */
 112
 113
 114 /*
 115  * Forward declarations
 116  */
 117 /* those whose use media objects need these routines */
 118 unsigned long media_granularity(MEDIA m);
 119 long long media_total_size(MEDIA m);
 120 long read_media(MEDIA m, long long offset, unsigned long count, void *address);
 121 long write_media(MEDIA m, long long offset, unsigned long count, void *address);
 122 void close_media(MEDIA m);
 123 void os_reload_media(MEDIA m);
 124
 125 /* those who define media objects need these routines also */
 126 long allocate_media_kind(void);
 127 MEDIA new_media(long size);
 128 void delete_media(MEDIA m);
 129
 130 /* those whose use media object iterators need these routines */
 131 void reset_media_iterator(MEDIA_ITERATOR m);
 132 char *step_media_iterator(MEDIA_ITERATOR m);
 133 void delete_media_iterator(MEDIA_ITERATOR m);
 134
 135 /* those who define media object iterators need these routines also */
 136 MEDIA_ITERATOR new_media_iterator(long size);
 137 void private_delete_media_iterator(MEDIA_ITERATOR m);
 138
 139 #endif /* __media__ */