| 1 | #include <glib.h> |
| 2 | #include <stdio.h> |
| 3 | |
| 4 | #include "sstack.h" |
| 5 | |
| 6 | /* This is the implementation of sstack, a data structure that holds |
| 7 | * operations done on a stack in order to play them on a stack a short |
| 8 | * while later. They are played when dependencies are fulfilled. The |
| 9 | * operations are held in a queue. |
| 10 | * |
| 11 | * Operations include PUSH of data, POP, as well as other special markers. |
| 12 | * |
| 13 | * Stack operations are defined by a struct sstack_item. Each struct |
| 14 | * sstack_item has 3 flags: |
| 15 | * - finished |
| 16 | * - processable |
| 17 | * - deletable |
| 18 | * |
| 19 | * Finished is raised when all the dependencies of the operation are |
| 20 | * fulfilled. POPs are always created finished because they have no |
| 21 | * dependencies. PUSHes are marked finished when their corresponding |
| 22 | * POP is added to the queueit is the PUSHes |
| 23 | * that contain the and EVENTs are always created finished. |
| 24 | * |
| 25 | * Once an operation is finished |
| 26 | */ |
| 27 | |
| 28 | void (*print_sstack_item_data)(struct sstack_item *); |
| 29 | |
| 30 | /* Debugging function: print a queue item */ |
| 31 | |
| 32 | static void print_item(struct sstack_item *item) |
| 33 | { |
| 34 | char *label; |
| 35 | |
| 36 | if(item->data_type == SSTACK_TYPE_PUSH) { |
| 37 | label = "PUSH"; |
| 38 | } |
| 39 | else if(item->data_type == SSTACK_TYPE_POP) { |
| 40 | label = "POP"; |
| 41 | } |
| 42 | else { |
| 43 | label = "UNKNOWN"; |
| 44 | } |
| 45 | |
| 46 | printf("%-10s %-2u%-2u%-2u", label, item->finished, item->processable, item->deletable); |
| 47 | /* hack: call this external, application-dependant function to show the private data in the item */ |
| 48 | print_sstack_item_data(item); |
| 49 | } |
| 50 | |
| 51 | /* Debugging function: print the queue as it is now */ |
| 52 | |
| 53 | void print_stack(struct sstack *stack) |
| 54 | { |
| 55 | int i; |
| 56 | |
| 57 | printf("************************\n"); |
| 58 | printf("** %-10s F P D\n", "label"); |
| 59 | for(i=0; i<stack->array->len; i++) { |
| 60 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, i); |
| 61 | |
| 62 | printf("** %-3d- ", i); |
| 63 | print_item(item); |
| 64 | } |
| 65 | printf("\n"); |
| 66 | } |
| 67 | |
| 68 | static void try_start_deleting(struct sstack *stack) |
| 69 | { |
| 70 | int index = stack->array->len-1; |
| 71 | |
| 72 | while(index >= 0 && g_array_index(stack->array, struct sstack_item *, index)->deletable) { |
| 73 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, index); |
| 74 | |
| 75 | if(item->delete_data_val) |
| 76 | item->delete_data_val(item->data_val); |
| 77 | |
| 78 | //g_array_free(item->depends, FALSE); |
| 79 | //g_array_free(item->rev_depends, FALSE); |
| 80 | g_free(item); |
| 81 | |
| 82 | g_array_remove_index(stack->array, index); |
| 83 | index--; |
| 84 | } |
| 85 | |
| 86 | if(stack->proc_index > stack->array->len) |
| 87 | stack->proc_index = stack->array->len; |
| 88 | } |
| 89 | |
| 90 | /* An item is deletable as soon as it is processed. However, all the items after it |
| 91 | * in the list must be deleted before it can be deleted. |
| 92 | * |
| 93 | * After this function, try_start_deleting must be called. |
| 94 | */ |
| 95 | |
| 96 | static void mark_deletable(struct sstack *stack, int index) |
| 97 | { |
| 98 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, index); |
| 99 | |
| 100 | item->deletable = 1; |
| 101 | |
| 102 | // if(index == stack->array->len - 1) { |
| 103 | // start_deleting(stack); |
| 104 | // } |
| 105 | } |
| 106 | |
| 107 | #if 0 |
| 108 | /* Called to process an index of the queue */ |
| 109 | |
| 110 | static void process(struct sstack *stack, int index) |
| 111 | { |
| 112 | g_assert(stack->proc_index == index); |
| 113 | |
| 114 | //printf("sstack: starting to process\n"); |
| 115 | while(stack->proc_index < stack->array->len) { |
| 116 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, stack->proc_index); |
| 117 | |
| 118 | if(!item->processable) |
| 119 | break; |
| 120 | |
| 121 | //printf("sstack: processing "); |
| 122 | //print_item(item); |
| 123 | |
| 124 | if(stack->process_func) { |
| 125 | stack->process_func(stack->process_func_arg, item); |
| 126 | } |
| 127 | else { |
| 128 | printf("warning: no process func\n"); |
| 129 | } |
| 130 | |
| 131 | stack->proc_index++; |
| 132 | |
| 133 | mark_deletable(stack, stack->proc_index-1); |
| 134 | if(item->pushpop >= 0 && item->pushpop < stack->proc_index-1) { |
| 135 | mark_deletable(stack, item->pushpop); |
| 136 | } |
| 137 | try_start_deleting(stack); |
| 138 | } |
| 139 | //printf("sstack: stopping processing\n"); |
| 140 | } |
| 141 | |
| 142 | /* Called to mark an index of the queue as processable */ |
| 143 | |
| 144 | static void mark_processable(struct sstack *stack, int index) |
| 145 | { |
| 146 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, index); |
| 147 | |
| 148 | item->processable = 1; |
| 149 | |
| 150 | if(stack->proc_index <= stack->array->len && stack->proc_index == index) { |
| 151 | process(stack, index); |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | /* Called to check whether an index of the queue could be marked processable. If so, |
| 156 | * mark it processable. |
| 157 | * |
| 158 | * To be processable, an item must: |
| 159 | * - be finished |
| 160 | * - have its push/pop dependency fulfilled |
| 161 | * - have its other dependencies fulfilled |
| 162 | */ |
| 163 | |
| 164 | static void try_mark_processable(struct sstack *stack, int index) |
| 165 | { |
| 166 | int i; |
| 167 | int all_finished = 1; |
| 168 | |
| 169 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, index); |
| 170 | |
| 171 | //for(i=0; i<stack->array->len; i++) { |
| 172 | // if(!g_array_index(stack->array, struct sstack_item *, index)->finished) { |
| 173 | // all_finished = 0; |
| 174 | // break; |
| 175 | // } |
| 176 | //} |
| 177 | |
| 178 | /* Theoritically, we should confirm that the push/pop dependency is |
| 179 | * finished, but in practice, it's not necessary. If we are a push, the |
| 180 | * corresponding pop is always finished. If we are a pop and we exist, |
| 181 | * the corresponding push is necessarily finished. |
| 182 | */ |
| 183 | |
| 184 | //if(all_finished) { |
| 185 | if(item->finished) { |
| 186 | mark_processable(stack, index); |
| 187 | } |
| 188 | //} |
| 189 | } |
| 190 | |
| 191 | /* Called to mark an index of the queue as finished */ |
| 192 | |
| 193 | static void mark_finished(struct sstack *stack, int index) |
| 194 | { |
| 195 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, index); |
| 196 | |
| 197 | item->finished = 1; |
| 198 | |
| 199 | try_mark_processable(stack, index); |
| 200 | } |
| 201 | |
| 202 | #endif |
| 203 | /* --------------------- */ |
| 204 | |
| 205 | static void try_advance_processing(struct sstack *stack) |
| 206 | { |
| 207 | //g_assert(stack->proc_index == index); |
| 208 | |
| 209 | //printf("sstack: starting to process\n"); |
| 210 | while(stack->proc_index < stack->array->len) { |
| 211 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, stack->proc_index); |
| 212 | |
| 213 | //if(!item->finished) { |
| 214 | // break; |
| 215 | //} |
| 216 | |
| 217 | //printf("sstack: processing "); |
| 218 | //print_item(item); |
| 219 | |
| 220 | if(stack->process_func) { |
| 221 | stack->process_func(stack->process_func_arg, item); |
| 222 | } |
| 223 | else { |
| 224 | printf("warning: no process func\n"); |
| 225 | } |
| 226 | |
| 227 | stack->proc_index++; |
| 228 | |
| 229 | if(item->data_type == SSTACK_TYPE_POP) |
| 230 | mark_deletable(stack, stack->proc_index-1); |
| 231 | if(item->pushpop >= 0 && item->pushpop < stack->proc_index-1) { |
| 232 | mark_deletable(stack, item->pushpop); |
| 233 | } |
| 234 | } |
| 235 | try_start_deleting(stack); |
| 236 | //printf("sstack: stopping processing\n"); |
| 237 | } |
| 238 | |
| 239 | |
| 240 | /* Add an item to the queue */ |
| 241 | |
| 242 | void sstack_add_item(struct sstack *stack, struct sstack_item *item) |
| 243 | { |
| 244 | int index; |
| 245 | |
| 246 | g_array_append_val(stack->array, item); |
| 247 | |
| 248 | //printf("stack after adding\n"); |
| 249 | //print_stack(stack); |
| 250 | |
| 251 | index = stack->array->len-1; |
| 252 | |
| 253 | if(item->data_type == SSTACK_TYPE_PUSH) { |
| 254 | int top_of_wait_pop_stack; |
| 255 | |
| 256 | if(stack->wait_pop_stack->len && g_array_index(stack->wait_pop_stack, int, stack->wait_pop_stack->len-1)) { |
| 257 | /* if the preceding is a wait_for_pop (and there is a preceding), push a wait_for_pop */ |
| 258 | const int one=1; |
| 259 | g_array_append_val(stack->wait_pop_stack, one); |
| 260 | } |
| 261 | else { |
| 262 | /* otherwise, push what the item wants */ |
| 263 | g_array_append_val(stack->wait_pop_stack, item->wait_pop); |
| 264 | } |
| 265 | |
| 266 | top_of_wait_pop_stack = g_array_index(stack->wait_pop_stack, int, stack->wait_pop_stack->len-1); |
| 267 | |
| 268 | g_array_append_val(stack->pushes, index); |
| 269 | |
| 270 | //printf("after pushing:\n"); |
| 271 | //print_stack(stack); |
| 272 | if(top_of_wait_pop_stack == 0) { |
| 273 | try_advance_processing(stack); |
| 274 | /* ASSERT that we processed the whole sstack */ |
| 275 | } |
| 276 | //printf("after processing:\n"); |
| 277 | //print_stack(stack); |
| 278 | } |
| 279 | else if(item->data_type == SSTACK_TYPE_POP) { |
| 280 | item->finished = 1; |
| 281 | |
| 282 | if(stack->pushes->len > 0) { |
| 283 | /* FIXME: confirm we are popping what we expected to pop */ |
| 284 | item->pushpop = g_array_index(stack->pushes, int, stack->pushes->len-1); |
| 285 | g_array_index(stack->array, struct sstack_item *, item->pushpop)->pushpop = index; |
| 286 | g_array_index(stack->array, struct sstack_item *, item->pushpop)->finished = 1; |
| 287 | |
| 288 | g_array_remove_index(stack->pushes, stack->pushes->len-1); |
| 289 | } |
| 290 | |
| 291 | if(stack->wait_pop_stack->len > 0) { |
| 292 | int top_of_wait_pop_stack; |
| 293 | |
| 294 | g_array_remove_index(stack->wait_pop_stack, stack->wait_pop_stack->len-1); |
| 295 | |
| 296 | if(stack->wait_pop_stack->len > 0) { |
| 297 | top_of_wait_pop_stack = g_array_index(stack->wait_pop_stack, int, stack->wait_pop_stack->len-1); |
| 298 | |
| 299 | if(top_of_wait_pop_stack == 0) |
| 300 | try_advance_processing(stack); |
| 301 | } |
| 302 | else { |
| 303 | try_advance_processing(stack); |
| 304 | } |
| 305 | } |
| 306 | else { |
| 307 | try_advance_processing(stack); |
| 308 | } |
| 309 | } |
| 310 | |
| 311 | //printf("stack after processing\n"); |
| 312 | //print_stack(stack); |
| 313 | } |
| 314 | |
| 315 | /* Force processing of all items */ |
| 316 | |
| 317 | void sstack_force_flush(struct sstack *stack) |
| 318 | { |
| 319 | int i; |
| 320 | |
| 321 | for(i=0; i<stack->array->len; i++) { |
| 322 | struct sstack_item *item = g_array_index(stack->array, struct sstack_item *, i); |
| 323 | |
| 324 | if(!item->finished) { |
| 325 | item->finished = 1; |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | try_advance_processing(stack); |
| 330 | } |
| 331 | |
| 332 | /* Create a new sstack */ |
| 333 | |
| 334 | struct sstack *sstack_new(void) |
| 335 | { |
| 336 | struct sstack *retval; |
| 337 | |
| 338 | retval = (struct sstack *) g_malloc(sizeof(struct sstack)); |
| 339 | |
| 340 | retval->array = g_array_new(FALSE, FALSE, sizeof(struct sstack_item *)); |
| 341 | retval->pushes = g_array_new(FALSE, FALSE, sizeof(int)); |
| 342 | retval->wait_pop_stack = g_array_new(FALSE, FALSE, sizeof(int)); |
| 343 | retval->proc_index = 0; |
| 344 | retval->process_func = NULL; |
| 345 | |
| 346 | return retval; |
| 347 | } |
| 348 | |
| 349 | /* Create a new sstack_item. Normally not invoked directly. See other functions below. */ |
| 350 | |
| 351 | struct sstack_item *sstack_item_new(void) |
| 352 | { |
| 353 | struct sstack_item *retval; |
| 354 | |
| 355 | retval = (struct sstack_item *) g_malloc(sizeof(struct sstack_item)); |
| 356 | retval->finished = 0; |
| 357 | retval->processable = 0; |
| 358 | retval->deletable = 0; |
| 359 | retval->data_type = 0; |
| 360 | retval->data_val = NULL; |
| 361 | retval->delete_data_val = NULL; |
| 362 | retval->pushpop = -1; |
| 363 | retval->wait_pop = 0; |
| 364 | //retval->depends = g_array_new(FALSE, FALSE, sizeof(int)); |
| 365 | //retval->rev_depends = g_array_new(FALSE, FALSE, sizeof(int)); |
| 366 | |
| 367 | return retval; |
| 368 | } |
| 369 | |
| 370 | /* Create a new sstack_item that will represent a PUSH operation */ |
| 371 | |
| 372 | struct sstack_item *sstack_item_new_push(unsigned char wait_pop) |
| 373 | { |
| 374 | struct sstack_item *retval = sstack_item_new(); |
| 375 | |
| 376 | retval->data_type = SSTACK_TYPE_PUSH; |
| 377 | retval->wait_pop = wait_pop; |
| 378 | |
| 379 | return retval; |
| 380 | } |
| 381 | |
| 382 | /* Create a new sstack_item that will represent a POP operation */ |
| 383 | |
| 384 | struct sstack_item *sstack_item_new_pop(void) |
| 385 | { |
| 386 | struct sstack_item *retval = sstack_item_new(); |
| 387 | |
| 388 | retval->data_type = SSTACK_TYPE_POP; |
| 389 | retval->finished = 1; |
| 390 | |
| 391 | return retval; |
| 392 | } |
| 393 | |
| 394 | /* Create a new sstack_item that will represent an EVENT operation */ |
| 395 | |
| 396 | struct sstack_item *sstack_item_new_event(void) |
| 397 | { |
| 398 | struct sstack_item *retval = sstack_item_new(); |
| 399 | |
| 400 | retval->data_type = SSTACK_TYPE_EVENT; |
| 401 | retval->finished = 1; |
| 402 | retval->processable = 1; |
| 403 | retval->deletable = 1; |
| 404 | |
| 405 | return retval; |
| 406 | } |