xref: /btstack/src/btstack_hid_parser.h (revision 0c7e4a253099699bdc9ba5a920d48e0bb18e6c70)
1 /*
2  * Copyright (C) 2017 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
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9  *    notice, this list of conditions and the following disclaimer.
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20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
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37 
38 /**
39  * @title HID Parser
40  *
41  * Single-pass HID Report Parser: HID Report is directly parsed without preprocessing HID Descriptor to minimize memory.
42  *
43  */
44 
45 #ifndef BTSTACK_HID_PARSER_H
46 #define BTSTACK_HID_PARSER_H
47 
48 #include <stdint.h>
49 #include "btstack_bool.h"
50 #include "btstack_hid.h"
51 
52 #if defined __cplusplus
53 extern "C" {
54 #endif
55 
56 typedef enum {
57     Main=0,
58     Global,
59     Local,
60     Reserved
61 } TagType;
62 
63 typedef enum {
64     Input=8,
65     Output,
66     Coll,
67     Feature,
68     EndColl
69 } MainItemTag;
70 
71 typedef enum {
72     UsagePage,
73     LogicalMinimum,
74     LogicalMaximum,
75     PhysicalMinimum,
76     PhysicalMaximum,
77     UnitExponent,
78     Unit,
79     ReportSize,
80     ReportID,
81     ReportCount,
82     Push,
83     Pop
84 } GlobalItemTag;
85 
86 typedef enum {
87     Usage,
88     UsageMinimum,
89     UsageMaximum,
90     DesignatorIndex,
91     DesignatorMinimum,
92     DesignatorMaximum,
93     StringIndex,
94     StringMinimum,
95     StringMaximum,
96     Delimiter
97 } LocalItemTag;
98 
99 typedef struct  {
100     int32_t  item_value;
101     uint16_t item_size;
102     uint8_t  item_type;
103     uint8_t  item_tag;
104     uint8_t  data_size;
105 } hid_descriptor_item_t;
106 
107 typedef enum {
108     BTSTACK_HID_PARSER_SCAN_FOR_REPORT_ITEM,
109     BTSTACK_HID_PARSER_USAGES_AVAILABLE,
110     BTSTACK_HID_PARSER_COMPLETE,
111 } btstack_hid_parser_state_t;
112 
113 typedef struct {
114     // Descriptor
115     const uint8_t * descriptor;
116     uint16_t        descriptor_pos;
117     uint16_t        descriptor_len;
118     // parsed item
119     bool            item_ready;
120     bool            valid;
121     hid_descriptor_item_t descriptor_item;
122 } btstack_hid_descriptor_iterator_t;
123 
124 typedef struct {
125 
126     // Descriptor
127     const uint8_t * descriptor;
128     uint16_t        descriptor_len;
129 
130     // Report
131     hid_report_type_t report_type;
132     const uint8_t * report;
133     uint16_t        report_len;
134 
135     // State
136     btstack_hid_parser_state_t state;
137 
138     hid_descriptor_item_t descriptor_item;
139 
140     uint16_t        descriptor_pos;
141     uint16_t        report_pos_in_bit;
142 
143     // usage pos and usage_page after last main item, used to find next usage
144     uint16_t        usage_pos;
145     uint16_t        usage_page;
146 
147     // usage generator
148     uint32_t        usage_minimum;
149     uint32_t        usage_maximum;
150     uint16_t        available_usages;
151     uint16_t        required_usages;
152     bool            usage_range;
153     uint8_t         active_record;
154 
155     // global
156     int32_t         global_logical_minimum;
157     int32_t         global_logical_maximum;
158     uint16_t        global_usage_page;
159     uint8_t         global_report_size;
160     uint8_t         global_report_count;
161     uint8_t         global_report_id;
162 } btstack_hid_parser_t;
163 
164 
165 /* API_START */
166 
167 /**
168  * @brief Init HID Descriptor iterator
169  * @param iterator
170  * @param hid_descriptor
171  * @param hid_descriptor_len
172  */
173 void btstack_hid_descriptor_iterator_init(btstack_hid_descriptor_iterator_t * iterator, const uint8_t * hid_descriptor, uint16_t hid_descriptor_len);
174 
175 /**
176  * @brief Check if HID Descriptor Items are available
177  * @param iterator
178  * @return
179  */
180 bool btstack_hid_descriptor_iterator_has_more(btstack_hid_descriptor_iterator_t * iterator);
181 
182 /**
183  * @brief Get next HID Descriptor Item
184  * @param iterator
185  * @return
186  */
187 const hid_descriptor_item_t * const btstack_hid_descriptor_iterator_get_item(btstack_hid_descriptor_iterator_t * iterator);
188 
189 /**
190  * @brief Returns if HID Descriptor was well formed
191  * @param iterator
192  * @return
193  */
194 bool btstack_hid_descriptor_iterator_valid(btstack_hid_descriptor_iterator_t * iterator);
195 
196 /**
197  * @brief Initialize HID Parser.
198  * @param parser state
199  * @param hid_descriptor
200  * @param hid_descriptor_len
201  * @param hid_report_type
202  * @param hid_report
203  * @param hid_report_len
204  */
205 void btstack_hid_parser_init(btstack_hid_parser_t * parser, const uint8_t * hid_descriptor, uint16_t hid_descriptor_len, hid_report_type_t hid_report_type, const uint8_t * hid_report, uint16_t hid_report_len);
206 
207 /**
208  * @brief Checks if more fields are available
209  * @param parser
210  */
211 bool btstack_hid_parser_has_more(btstack_hid_parser_t * parser);
212 
213 /**
214  * @brief Get next field
215  * @param parser
216  * @param usage_page
217  * @param usage
218  * @param value provided in HID report
219  */
220 void btstack_hid_parser_get_field(btstack_hid_parser_t * parser, uint16_t * usage_page, uint16_t * usage, int32_t * value);
221 
222 
223 /**
224  * @brief Parses descriptor item
225  * @param item
226  * @param hid_descriptor
227  * @param hid_descriptor_len
228  * @return true if item has been parsed successfully
229  */
230 bool btstack_hid_parse_descriptor_item(hid_descriptor_item_t * item, const uint8_t * hid_descriptor, uint16_t hid_descriptor_len);
231 
232 /**
233  * @brief Parses descriptor and returns report size for given report ID and report type
234  * @param report_id
235  * @param report_type
236  * @param hid_descriptor_len
237  * @param hid_descriptor
238  * @return report size in bytes or 0 on parsing error
239  */
240 int btstack_hid_get_report_size_for_id(int report_id, hid_report_type_t report_type, uint16_t hid_descriptor_len, const uint8_t * hid_descriptor);
241 
242 /**
243  * @brief Parses descriptor and returns status for given report ID
244  * @param report_id
245  * @param hid_descriptor_len
246  * @param hid_descriptor
247  * @return status for report id
248  */
249 hid_report_id_status_t btstack_hid_id_valid(int report_id, uint16_t hid_descriptor_len, const uint8_t * hid_descriptor);
250 
251 /**
252  * @brief Parses descriptor and returns true if report ID found
253  * @param hid_descriptor_len
254  * @param hid_descriptor
255  * @return true if report ID declared in descriptor
256  */
257 bool btstack_hid_report_id_declared(uint16_t hid_descriptor_len, const uint8_t * hid_descriptor);
258 
259 /* API_END */
260 
261 #if defined __cplusplus
262 }
263 #endif
264 
265 #endif // BTSTACK_HID_PARSER_H
266