1 /* 2 * Copyright (C) 2024 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN 24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 #define BTSTACK_FILE__ "btstack_hsm.c" 38 39 #include <stddef.h> 40 #include <string.h> 41 #include <stdbool.h> 42 43 #include "btstack_config.h" 44 #include "btstack_debug.h" 45 46 #include "btstack_hsm.h" 47 48 btstack_hsm_state_t btstack_hsm_transit(btstack_hsm_t * const me, btstack_hsm_state_handler_t const target) { 49 me->temp = target; 50 return BTSTACK_HSM_TRAN_STATUS; 51 } 52 53 btstack_hsm_state_t btstack_hsm_super(btstack_hsm_t * const me, btstack_hsm_state_handler_t const target) { 54 me->temp = target; 55 return BTSTACK_HSM_SUPER_STATUS; 56 } 57 58 btstack_hsm_state_t btstack_hsm_top(btstack_hsm_t * const me, btstack_hsm_event_t const * const e) { 59 UNUSED(me); 60 UNUSED(e); 61 return BTSTACK_HSM_IGNORED_STATUS; 62 } 63 64 void btstack_hsm_constructor(btstack_hsm_t * const me, btstack_hsm_state_handler_t initial, btstack_hsm_state_handler_t path[], int8_t depth) { 65 me->state = btstack_hsm_top; 66 me->temp = initial; 67 me->path = path; 68 me->depth = depth; 69 } 70 71 static btstack_hsm_state_t btstack_hsm_get_super( btstack_hsm_t * const me, btstack_hsm_state_handler_t const handler) { 72 // empty event to trigger default state action, a.k. the super state 73 static btstack_hsm_event_t const empty_evt = { BTSTACK_HSM_EMPTY_SIG }; 74 return handler( me, &empty_evt ); 75 } 76 77 static btstack_hsm_event_t const entry_evt = { BTSTACK_HSM_ENTRY_SIG }; 78 static btstack_hsm_event_t const exit_evt = { BTSTACK_HSM_EXIT_SIG }; 79 80 void btstack_hsm_init(btstack_hsm_t * const me, btstack_hsm_event_t const * const e) { 81 btstack_assert(me->state != NULL); 82 btstack_assert(me->temp != NULL); 83 btstack_hsm_state_handler_t target = me->state; 84 btstack_hsm_state_t status = me->temp(me, e); 85 btstack_assert( status == BTSTACK_HSM_TRAN_STATUS ); 86 static btstack_hsm_event_t const init_evt = { BTSTACK_HSM_INIT_SIG }; 87 88 int_fast8_t level; 89 btstack_hsm_state_handler_t *root_path = me->path; 90 memset(root_path, 0, sizeof(btstack_hsm_state_handler_t)*me->depth); 91 92 do { 93 level = 0; 94 btstack_hsm_state_handler_t current = me->temp; 95 for(; current != target; current=me->temp, level++ ) { 96 root_path[level] = current; 97 btstack_hsm_get_super( me, current ); 98 } 99 for(; level>0;) { 100 root_path[--level]( me, &entry_evt ); 101 } 102 target = root_path[0]; 103 status = target( me, &init_evt ); 104 } while (status == BTSTACK_HSM_TRAN_STATUS); 105 btstack_assert( status != BTSTACK_HSM_TRAN_STATUS ); 106 me->state = target; 107 } 108 109 static void btstack_hsm_handler_super_cache( btstack_hsm_t * const me, btstack_hsm_state_handler_t cache[], int idx, btstack_hsm_state_handler_t handler ) { 110 if( cache[idx] == NULL ) { 111 cache[idx] = handler; 112 btstack_hsm_get_super(me, handler); 113 } else { 114 me->temp = cache[idx]; 115 } 116 } 117 118 btstack_hsm_state_t btstack_hsm_dispatch(btstack_hsm_t * const me, btstack_hsm_event_t const * const e) { 119 btstack_hsm_state_t status; 120 btstack_hsm_state_handler_t current = me->state; 121 do { 122 status = current(me, e); 123 // if the state doesn't handle the event try at the super state too 124 if( status == BTSTACK_HSM_UNHANDLED_STATUS ) { 125 status = btstack_hsm_get_super( me, current ); 126 } 127 current = me->temp; 128 } while( status == BTSTACK_HSM_SUPER_STATUS ); 129 130 // if we don't switch states we are done now 131 if( status != BTSTACK_HSM_TRAN_STATUS ) { 132 return status; 133 } 134 btstack_hsm_state_handler_t source = me->state; 135 btstack_hsm_state_handler_t target = me->temp; 136 btstack_hsm_state_handler_t *root_path = me->path; 137 memset(root_path, 0, sizeof(btstack_hsm_state_handler_t)*me->depth); 138 139 // why should that be possible/necessary? 140 btstack_assert( source != target ); 141 142 // handle entry/exit edges 143 int_fast8_t level = 0; 144 bool lca_found = false; 145 // calculates the lowest common ancestor of the state graph 146 for(; source != btstack_hsm_top; source=me->temp) { 147 level = 0; 148 for(current=target; current != btstack_hsm_top; current=me->temp, ++level ) { 149 if( current == source ) { 150 lca_found = true; 151 break; 152 } 153 154 btstack_hsm_handler_super_cache( me, root_path, level, current ); 155 } 156 if( lca_found == true ) { 157 break; 158 } 159 source( me, &exit_evt ); 160 btstack_hsm_get_super( me, source ); 161 } 162 163 for(level--; level > 0; ) { 164 root_path[--level]( me, &entry_evt ); 165 } 166 me->state = target; 167 return status; 168 } 169 170