1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ANDROID_RADIO_METADATA_HIDDEN_H
18 #define ANDROID_RADIO_METADATA_HIDDEN_H
19 
20 #include <stdbool.h>
21 #include <system/radio.h>
22 #include <system/radio_metadata.h>
23 
24 /* default size allocated for a metadata buffer in 32 bits units */
25 #define RADIO_METADATA_DEFAULT_SIZE 64
26 /* maximum size allocated for a metadata buffer in 32 bits units */
27 #define RADIO_METADATA_MAX_SIZE (RADIO_METADATA_DEFAULT_SIZE << 12)
28 
29 /* meta data entry in a meta data buffer */
30 typedef struct radio_metadata_entry {
31     radio_metadata_key_t    key;
32     radio_metadata_type_t   type;
33     unsigned int            size;
34     unsigned char           data[];
35 } radio_metadata_entry_t;
36 
37 
38 /**
39 * meta data buffer layout:
40 *
41 *   |    <---  32 bit   --->    |
42 *   |---------------------------|
43 *   | channel                   |
44 *   |---------------------------|
45 *   | sub_channel               |
46 *   |---------------------------|
47 *   | size_int                  | total size in 32 bit units including header and index
48 *   |---------------------------|
49 *   | count                     | number of entries
50 *   |---------------------------|<--+
51 *   | first entry               |   |
52 *   |                           |   |
53 *   |---------------------------|<+ |
54 *   | second entry              | | |
55 *   |                           | | |
56 *   |                           | | |
57 *   |---------------------------| | |
58 *   |     :                     | | |
59 *   |---------------------------| | |       \
60 *   | offset of next free space | | |       |
61 *   |---------------------------| | |       |
62 *   |     :                     | | |       |
63 *   |---------------------------| | |       >  index
64 *   | offset of second entry    |-+ |       |
65 *   |---------------------------|   |       |
66 *   | offset of first entry     |---+       |
67 *   |---------------------------|           /
68 *
69 *   A radio meta data buffer is allocated with radio_metadata_allocate() and released with
70 *   radio_metadata_deallocate().
71 *   Meta data entries are added with radio_metadata_add_xxx() where xxx is int, text or raw.
72 *   The buffer is allocated with a default size (RADIO_METADATA_DEFAULT_SIZE entries)
73 *   by radio_metadata_allocate() and reallocated if needed by radio_metadata_add_xxx()
74 */
75 
76 /* Radio meta data buffer header */
77 typedef struct radio_metadata_buffer {
78     unsigned int channel;       /* channel (frequency) this meta data is associated with */
79     unsigned int sub_channel;   /* sub channel this meta data is associated with */
80     unsigned int size_int;      /* Total size in 32 bit word units */
81     unsigned int count;         /* number of meta data entries */
82 } radio_metadata_buffer_t;
83 
84 
85 
86 #endif  // ANDROID_RADIO_METADATA_HIDDEN_H
87