src/data_internal.h

   1 /*
   2  * Copyright (c) 2009-2012 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 /*
  22  * IMPORTANT: This header file describes INTERNAL interfaces to libdispatch
  23  * which are subject to change in future releases of Mac OS X. Any applications
  24  * relying on these interfaces WILL break.
  25  */
  26
  27 #ifndef __DISPATCH_DATA_INTERNAL__
  28 #define __DISPATCH_DATA_INTERNAL__
  29
  30 #ifndef __DISPATCH_INDIRECT__
  31 #error "Please #include <dispatch/dispatch.h> instead of this file directly."
  32 #include <dispatch/base.h> // for HeaderDoc
  33 #endif
  34
  35 typedef struct range_record_s {
  36         dispatch_data_t data_object;
  37         size_t from;
  38         size_t length;
  39 } range_record;
  40
  41 #if USE_OBJC
  42 #if OS_OBJECT_USE_OBJC
  43 @interface DISPATCH_CLASS(data) : NSObject <DISPATCH_CLASS(data)>
  44 @end
  45 #endif
  46 DISPATCH_OBJC_CLASS_DECL(data);
  47 DISPATCH_OBJC_CLASS_DECL(data_empty);
  48 #define DISPATCH_DATA_CLASS DISPATCH_OBJC_CLASS(data)
  49 #define DISPATCH_DATA_EMPTY_CLASS DISPATCH_OBJC_CLASS(data_empty)
  50 #else // USE_OBJC
  51 DISPATCH_CLASS_DECL(data);
  52 #define DISPATCH_DATA_CLASS DISPATCH_VTABLE(data)
  53 #define DISPATCH_DATA_EMPTY_CLASS DISPATCH_VTABLE(data)
  54 #endif // USE_OBJC
  55
  56 struct dispatch_data_s {
  57 #if USE_OBJC
  58         const void *do_vtable;
  59         dispatch_queue_t do_targetq;
  60         void *ctxt;
  61         void *finalizer;
  62 #else // USE_OBJC
  63         DISPATCH_STRUCT_HEADER(data);
  64 #endif // USE_OBJC
  65         const void *buf;
  66         dispatch_block_t destructor;
  67         size_t size, num_records;
  68         range_record records[0];
  69 };
  70
  71 DISPATCH_ALWAYS_INLINE
  72 static inline bool
  73 _dispatch_data_leaf(struct dispatch_data_s *dd)
  74 {
  75         return dd->num_records == 0;
  76 }
  77
  78 /*
  79  * This is about the number of records required to hold that dispatch data
  80  * if it's not a leaf. Callers either want that value, or have to special
  81  * case the case when the dispatch data *is* a leaf before (and that the actual
  82  * embeded record count of that dispatch data is 0)
  83  */
  84 DISPATCH_ALWAYS_INLINE
  85 static inline size_t
  86 _dispatch_data_num_records(struct dispatch_data_s *dd)
  87 {
  88         return dd->num_records ?: 1;
  89 }
  90
  91 typedef dispatch_data_t (*dispatch_transform_t)(dispatch_data_t data);
  92
  93 struct dispatch_data_format_type_s {
  94         uint64_t type;
  95         uint64_t input_mask;
  96         uint64_t output_mask;
  97         dispatch_transform_t decode;
  98         dispatch_transform_t encode;
  99 };
 100
 101 void dispatch_data_init(dispatch_data_t data, const void *buffer, size_t size,
 102                 dispatch_block_t destructor);
 103 void _dispatch_data_dispose(dispatch_data_t data);
 104 size_t _dispatch_data_debug(dispatch_data_t data, char* buf, size_t bufsiz);
 105 const void*
 106 _dispatch_data_get_flattened_bytes(struct dispatch_data_s *dd);
 107
 108 #if !defined(__cplusplus)
 109 #if !__OBJC2__
 110 const dispatch_block_t _dispatch_data_destructor_inline;
 111 #define DISPATCH_DATA_DESTRUCTOR_INLINE (_dispatch_data_destructor_inline)
 112 #endif // !__OBJC2__
 113
 114 /*
 115  * the out parameters are about seeing "through" trivial subranges
 116  * so for something like this: dd = { subrange [ dd1, offset1 ] },
 117  * this will return { dd1, offset + offset1 }
 118  *
 119  * If the dispatch object isn't a trivial subrange, it returns { dd, offset }
 120  */
 121 DISPATCH_ALWAYS_INLINE
 122 static inline const void*
 123 _dispatch_data_map_direct(struct dispatch_data_s *dd, size_t offset,
 124                 struct dispatch_data_s **dd_out, size_t *from_out)
 125 {
 126         const void *buffer = NULL;
 127
 128         dispatch_assert(dd->size);
 129         if (slowpath(!_dispatch_data_leaf(dd)) &&
 130                         _dispatch_data_num_records(dd) == 1) {
 131                 offset += dd->records[0].from;
 132                 dd = (struct dispatch_data_s *)dd->records[0].data_object;
 133         }
 134
 135         if (fastpath(_dispatch_data_leaf(dd))) {
 136                 buffer = dd->buf + offset;
 137         } else {
 138                 buffer = dispatch_atomic_load((void **)&dd->buf, relaxed);
 139                 if (buffer) {
 140                         buffer += offset;
 141                 }
 142         }
 143         if (dd_out) *dd_out = dd;
 144         if (from_out) *from_out = offset;
 145         return buffer;
 146 }
 147
 148 #endif // !defined(__cplusplus)
 149
 150 #endif // __DISPATCH_DATA_INTERNAL__