src/marshal.h

   1 /* -*- mode: c; c-file-style: "openbsd" -*- */
   2 /*
   3  * Copyright (c) 2012 Vincent Bernat <bernat@luffy.cx>
   4  *
   5  * Permission to use, copy, modify, and/or distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #ifndef _MARSHAL_H
  19 #define _MARSHAL_H
  20
  21 #include <stddef.h>
  22 #include <sys/types.h>
  23
  24 struct marshal_info;
  25 enum marshal_subinfo_kind {
  26         pointer,
  27         substruct,
  28         ignore,
  29 };
  30 #define MARSHAL_INFO_POINTER 1
  31 #define MARSHAL_INFO_SUB     2
  32 struct marshal_subinfo {
  33         size_t offset;       /* Offset compared to parent structure */
  34         size_t offset2;      /* Ancillary offset (for related data) */
  35         enum marshal_subinfo_kind kind; /* Kind of substructure */
  36         struct  marshal_info *mi;
  37 };
  38 #define MARSHAL_SUBINFO_NULL { .offset = 0, .offset2 = 0, .kind = ignore, .mi = NULL }
  39 struct marshal_info {
  40         char   *name;           /* Name of structure */
  41         size_t  size;           /* Size of the structure */
  42 #if defined __GNUC__ && __GNUC__ < 3
  43         /* With gcc 2.96, flexible arrays are not supported, even with
  44          * -std=gnu99. And with gcc 3.x, zero-sized arrays cannot be statically
  45          * initialized (with more than one element). */
  46         struct marshal_subinfo pointers[0]; /* Pointer to other structures */
  47 #else
  48         struct marshal_subinfo pointers[]; /* Pointer to other structures */
  49 #endif
  50 };
  51 /* Special case for strings */
  52 extern struct marshal_info marshal_info_string;
  53 extern struct marshal_info marshal_info_fstring;
  54 extern struct marshal_info marshal_info_ignore;
  55
  56 /* Declare a new marshal_info struct named after the type we want to
  57    marshal. The marshalled type has to be a structure. */
  58 #define MARSHAL_INFO(type) marshal_info_##type
  59 #ifdef MARSHAL_EXPORT
  60 #define MARSHAL_BEGIN(type) struct marshal_info MARSHAL_INFO(type) =    \
  61         {                                                               \
  62                 .name = #type,                                          \
  63                 .size = sizeof(struct type),                            \
  64                 .pointers = {
  65 #define MARSHAL_ADD(_kind, type, subtype, member)               \
  66         { .offset = offsetof(struct type, member),              \
  67           .offset2 = 0,                                         \
  68           .kind = _kind,                                        \
  69           .mi = &MARSHAL_INFO(subtype) },
  70 #define MARSHAL_FSTR(type, member, len)                         \
  71         { .offset = offsetof(struct type, member),              \
  72           .offset2 = offsetof(struct type, len),                \
  73           .kind = pointer,                                      \
  74           .mi = &marshal_info_fstring },
  75 #define MARSHAL_END MARSHAL_SUBINFO_NULL }}
  76 #else
  77 #define MARSHAL_BEGIN(type) extern struct marshal_info MARSHAL_INFO(type)
  78 #define MARSHAL_ADD(...)
  79 #define MARSHAL_FSTR(...)
  80 #define MARSHAL_END
  81 #endif
  82 /* Shortcuts */
  83 #define MARSHAL_POINTER(...) MARSHAL_ADD(pointer, ##__VA_ARGS__)
  84 #define MARSHAL_SUBSTRUCT(...) MARSHAL_ADD(substruct, ##__VA_ARGS__)
  85 #define MARSHAL_STR(type, member) MARSHAL_ADD(pointer, type, string, member)
  86 #define MARSHAL_IGNORE(type, member) MARSHAL_ADD(ignore, type, ignore, member)
  87 #define MARSHAL_TQE(type, field)                         \
  88         MARSHAL_POINTER(type, type, field.tqe_next)      \
  89         MARSHAL_IGNORE(type, field.tqe_prev)
  90 /* Support for TAILQ list is partial. Access to last and previous
  91    elements is not available. Some operations are therefore not
  92    possible. However, TAILQ_FOREACH and TAILQ_REMOVE are still
  93    available. */
  94 #define MARSHAL_TQH(type, subtype)                       \
  95         MARSHAL_POINTER(type, subtype, tqh_first)        \
  96         MARSHAL_IGNORE(type, tqh_last)
  97 #define MARSHAL_SUBTQ(type, subtype, field)              \
  98         MARSHAL_POINTER(type, subtype, field.tqh_first)  \
  99         MARSHAL_IGNORE(type, field.tqh_last)
 100 #define MARSHAL(type)                   \
 101         MARSHAL_BEGIN(type)             \
 102         MARSHAL_END
 103 #define MARSHAL_TQ(type, subtype)       \
 104         MARSHAL_BEGIN(type)             \
 105         MARSHAL_TQH(type, subtype)      \
 106         MARSHAL_END
 107
 108 /* Serialization */
 109 size_t  marshal_serialize_(struct marshal_info *, void *, void **, int, void *, int);
 110 #define marshal_serialize(type, o, output) marshal_serialize_(&MARSHAL_INFO(type), o, output, 0, NULL, 0)
 111
 112 /* Unserialization */
 113 size_t  marshal_unserialize_(struct marshal_info *, void *, size_t, void **, void*, int, int);
 114 #define marshal_unserialize(type, o, l, input) \
 115         marshal_unserialize_(&MARSHAL_INFO(type), o, l, (void **)input, NULL, 0, 0)
 116
 117 #endif