libsigrokdecode  0.5.2
sigrok protocol decoding library
instance.c
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1 /*
2  * This file is part of the libsigrokdecode project.
3  *
4  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
5  * Copyright (C) 2012 Bert Vermeulen <bert@biot.com>
6  *
7  * This program is free software: you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation, either version 3 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program. If not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include <config.h>
22 #include "libsigrokdecode-internal.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
23 #include "libsigrokdecode.h"
24 #include <glib.h>
25 #include <inttypes.h>
26 #include <stdlib.h>
27 #include <stdint.h>
28 
29 /** @cond PRIVATE */
30 
31 extern SRD_PRIV GSList *sessions;
32 
33 static void srd_inst_join_decode_thread(struct srd_decoder_inst *di);
34 static void srd_inst_reset_state(struct srd_decoder_inst *di);
35 SRD_PRIV void oldpins_array_seed(struct srd_decoder_inst *di);
36 SRD_PRIV void oldpins_array_free(struct srd_decoder_inst *di);
37 
38 /** @endcond */
39 
40 /**
41  * @file
42  *
43  * Decoder instance handling.
44  */
45 
46 /**
47  * @defgroup grp_instances Decoder instances
48  *
49  * Decoder instance handling.
50  *
51  * @{
52  */
53 
54 /**
55  * Set one or more options in a decoder instance.
56  *
57  * Handled options are removed from the hash.
58  *
59  * @param di Decoder instance.
60  * @param options A GHashTable of options to set.
61  *
62  * @return SRD_OK upon success, a (negative) error code otherwise.
63  *
64  * @since 0.1.0
65  */
67  GHashTable *options)
68 {
69  struct srd_decoder_option *sdo;
70  PyObject *py_di_options, *py_optval;
71  GVariant *value;
72  GSList *l;
73  double val_double;
74  gint64 val_int;
75  int ret;
76  const char *val_str;
77  PyGILState_STATE gstate;
78 
79  if (!di) {
80  srd_err("Invalid decoder instance.");
81  return SRD_ERR_ARG;
82  }
83 
84  if (!options) {
85  srd_err("Invalid options GHashTable.");
86  return SRD_ERR_ARG;
87  }
88 
89  gstate = PyGILState_Ensure();
90 
91  if (!PyObject_HasAttrString(di->decoder->py_dec, "options")) {
92  /* Decoder has no options. */
93  PyGILState_Release(gstate);
94  if (g_hash_table_size(options) == 0) {
95  /* No options provided. */
96  return SRD_OK;
97  } else {
98  srd_err("Protocol decoder has no options.");
99  return SRD_ERR_ARG;
100  }
101  return SRD_OK;
102  }
103 
104  ret = SRD_ERR_PYTHON;
105  py_optval = NULL;
106 
107  /*
108  * The 'options' tuple is a class variable, but we need to
109  * change it. Changing it directly will affect the entire class,
110  * so we need to create a new object for it, and populate that
111  * instead.
112  */
113  if (!(py_di_options = PyObject_GetAttrString(di->py_inst, "options")))
114  goto err_out;
115  Py_DECREF(py_di_options);
116  py_di_options = PyDict_New();
117  PyObject_SetAttrString(di->py_inst, "options", py_di_options);
118 
119  for (l = di->decoder->options; l; l = l->next) {
120  sdo = l->data;
121  if ((value = g_hash_table_lookup(options, sdo->id))) {
122  /* A value was supplied for this option. */
123  if (!g_variant_type_equal(g_variant_get_type(value),
124  g_variant_get_type(sdo->def))) {
125  srd_err("Option '%s' should have the same type "
126  "as the default value.", sdo->id);
127  goto err_out;
128  }
129  } else {
130  /* Use default for this option. */
131  value = sdo->def;
132  }
133  if (g_variant_is_of_type(value, G_VARIANT_TYPE_STRING)) {
134  val_str = g_variant_get_string(value, NULL);
135  if (!(py_optval = PyUnicode_FromString(val_str))) {
136  /* Some UTF-8 encoding error. */
137  PyErr_Clear();
138  srd_err("Option '%s' requires a UTF-8 string value.", sdo->id);
139  goto err_out;
140  }
141  } else if (g_variant_is_of_type(value, G_VARIANT_TYPE_INT64)) {
142  val_int = g_variant_get_int64(value);
143  if (!(py_optval = PyLong_FromLong(val_int))) {
144  /* ValueError Exception */
145  PyErr_Clear();
146  srd_err("Option '%s' has invalid integer value.", sdo->id);
147  goto err_out;
148  }
149  } else if (g_variant_is_of_type(value, G_VARIANT_TYPE_DOUBLE)) {
150  val_double = g_variant_get_double(value);
151  if (!(py_optval = PyFloat_FromDouble(val_double))) {
152  /* ValueError Exception */
153  PyErr_Clear();
154  srd_err("Option '%s' has invalid float value.",
155  sdo->id);
156  goto err_out;
157  }
158  }
159  if (PyDict_SetItemString(py_di_options, sdo->id, py_optval) == -1)
160  goto err_out;
161  /* Not harmful even if we used the default. */
162  g_hash_table_remove(options, sdo->id);
163  }
164  if (g_hash_table_size(options) != 0)
165  srd_warn("Unknown options specified for '%s'", di->inst_id);
166 
167  ret = SRD_OK;
168 
169 err_out:
170  Py_XDECREF(py_optval);
171  if (PyErr_Occurred()) {
172  srd_exception_catch("Stray exception in srd_inst_option_set()");
173  ret = SRD_ERR_PYTHON;
174  }
175  PyGILState_Release(gstate);
176 
177  return ret;
178 }
179 
180 /* Helper GComparefunc for g_slist_find_custom() in srd_inst_channel_set_all(). */
181 static gint compare_channel_id(const struct srd_channel *pdch,
182  const char *channel_id)
183 {
184  return strcmp(pdch->id, channel_id);
185 }
186 
187 /**
188  * Set all channels in a decoder instance.
189  *
190  * This function sets _all_ channels for the specified decoder instance, i.e.,
191  * it overwrites any channels that were already defined (if any).
192  *
193  * @param di Decoder instance.
194  * @param new_channels A GHashTable of channels to set. Key is channel name,
195  * value is the channel number. Samples passed to this
196  * instance will be arranged in this order.
197  *
198  * @return SRD_OK upon success, a (negative) error code otherwise.
199  *
200  * @since 0.4.0
201  */
203  GHashTable *new_channels)
204 {
205  GVariant *channel_val;
206  GList *l;
207  GSList *sl;
208  struct srd_channel *pdch;
209  int *new_channelmap, new_channelnum, num_required_channels, i;
210  char *channel_id;
211 
212  srd_dbg("Setting channels for instance %s with list of %d channels.",
213  di->inst_id, g_hash_table_size(new_channels));
214 
215  if (g_hash_table_size(new_channels) == 0)
216  /* No channels provided. */
217  return SRD_OK;
218 
219  if (di->dec_num_channels == 0) {
220  /* Decoder has no channels. */
221  srd_err("Protocol decoder %s has no channels to define.",
222  di->decoder->name);
223  return SRD_ERR_ARG;
224  }
225 
226  new_channelmap = g_malloc0(sizeof(int) * di->dec_num_channels);
227 
228  /*
229  * For now, map all indexes to channel -1 (can be overridden later).
230  * This -1 is interpreted as an unspecified channel later.
231  */
232  for (i = 0; i < di->dec_num_channels; i++)
233  new_channelmap[i] = -1;
234 
235  for (l = g_hash_table_get_keys(new_channels); l; l = l->next) {
236  channel_id = l->data;
237  channel_val = g_hash_table_lookup(new_channels, channel_id);
238  if (!g_variant_is_of_type(channel_val, G_VARIANT_TYPE_INT32)) {
239  /* Channel name was specified without a value. */
240  srd_err("No channel number was specified for %s.",
241  channel_id);
242  g_free(new_channelmap);
243  return SRD_ERR_ARG;
244  }
245  new_channelnum = g_variant_get_int32(channel_val);
246  if (!(sl = g_slist_find_custom(di->decoder->channels, channel_id,
247  (GCompareFunc)compare_channel_id))) {
248  /* Fall back on optional channels. */
249  if (!(sl = g_slist_find_custom(di->decoder->opt_channels,
250  channel_id, (GCompareFunc)compare_channel_id))) {
251  srd_err("Protocol decoder %s has no channel "
252  "'%s'.", di->decoder->name, channel_id);
253  g_free(new_channelmap);
254  return SRD_ERR_ARG;
255  }
256  }
257  pdch = sl->data;
258  new_channelmap[pdch->order] = new_channelnum;
259  srd_dbg("Setting channel mapping: %s (PD ch idx %d) = input data ch idx %d.",
260  pdch->id, pdch->order, new_channelnum);
261  }
262 
263  srd_dbg("Final channel map:");
264  num_required_channels = g_slist_length(di->decoder->channels);
265  for (i = 0; i < di->dec_num_channels; i++) {
266  GSList *ll = g_slist_nth(di->decoder->channels, i);
267  if (!ll)
268  ll = g_slist_nth(di->decoder->opt_channels,
269  i - num_required_channels);
270  pdch = ll->data;
271  srd_dbg(" - PD ch idx %d (%s) = input data ch idx %d (%s)", i,
272  pdch->id, new_channelmap[i],
273  (i < num_required_channels) ? "required" : "optional");
274  }
275 
276  /* Report an error if not all required channels were specified. */
277  for (i = 0; i < num_required_channels; i++) {
278  if (new_channelmap[i] != -1)
279  continue;
280  pdch = g_slist_nth(di->decoder->channels, i)->data;
281  srd_err("Required channel '%s' (index %d) was not specified.",
282  pdch->id, i);
283  g_free(new_channelmap);
284  return SRD_ERR;
285  }
286 
287  g_free(di->dec_channelmap);
288  di->dec_channelmap = new_channelmap;
289 
290  return SRD_OK;
291 }
292 
293 /**
294  * Create a new protocol decoder instance.
295  *
296  * @param sess The session holding the protocol decoder instance.
297  * Must not be NULL.
298  * @param decoder_id Decoder 'id' field.
299  * @param options GHashtable of options which override the defaults set in
300  * the decoder class. May be NULL.
301  *
302  * @return Pointer to a newly allocated struct srd_decoder_inst, or
303  * NULL in case of failure.
304  *
305  * @since 0.3.0
306  */
307 SRD_API struct srd_decoder_inst *srd_inst_new(struct srd_session *sess,
308  const char *decoder_id, GHashTable *options)
309 {
310  int i;
311  struct srd_decoder *dec;
312  struct srd_decoder_inst *di;
313  char *inst_id;
314  PyGILState_STATE gstate;
315 
316  i = 1;
317  srd_dbg("Creating new %s instance.", decoder_id);
318 
319  if (!sess)
320  return NULL;
321 
322  if (!(dec = srd_decoder_get_by_id(decoder_id))) {
323  srd_err("Protocol decoder %s not found.", decoder_id);
324  return NULL;
325  }
326 
327  di = g_malloc0(sizeof(struct srd_decoder_inst));
328 
329  di->decoder = dec;
330  di->sess = sess;
331 
332  if (options) {
333  inst_id = g_hash_table_lookup(options, "id");
334  if (inst_id)
335  di->inst_id = g_strdup(inst_id);
336  g_hash_table_remove(options, "id");
337  }
338 
339  /* Create a unique instance ID (as none was provided). */
340  if (!di->inst_id) {
341  di->inst_id = g_strdup_printf("%s-%d", decoder_id, i++);
342  while (srd_inst_find_by_id(sess, di->inst_id)) {
343  g_free(di->inst_id);
344  di->inst_id = g_strdup_printf("%s-%d", decoder_id, i++);
345  }
346  }
347 
348  /*
349  * Prepare a default channel map, where samples come in the
350  * order in which the decoder class defined them.
351  */
352  di->dec_num_channels = g_slist_length(di->decoder->channels) +
353  g_slist_length(di->decoder->opt_channels);
354  if (di->dec_num_channels) {
355  di->dec_channelmap =
356  g_malloc(sizeof(int) * di->dec_num_channels);
357  for (i = 0; i < di->dec_num_channels; i++)
358  di->dec_channelmap[i] = i;
359  /*
360  * Will be used to prepare a sample at every iteration
361  * of the instance's decode() method.
362  */
363  di->channel_samples = g_malloc(di->dec_num_channels);
364  }
365 
366  /* Default to the initial pins being the same as in sample 0. */
367  oldpins_array_seed(di);
368 
369  gstate = PyGILState_Ensure();
370 
371  /* Create a new instance of this decoder class. */
372  if (!(di->py_inst = PyObject_CallObject(dec->py_dec, NULL))) {
373  if (PyErr_Occurred())
374  srd_exception_catch("Failed to create %s instance",
375  decoder_id);
376  PyGILState_Release(gstate);
377  g_free(di->dec_channelmap);
378  g_free(di);
379  return NULL;
380  }
381 
382  PyGILState_Release(gstate);
383 
384  if (options && srd_inst_option_set(di, options) != SRD_OK) {
385  g_free(di->dec_channelmap);
386  g_free(di);
387  return NULL;
388  }
389 
390  di->condition_list = NULL;
391  di->match_array = NULL;
392  di->abs_start_samplenum = 0;
393  di->abs_end_samplenum = 0;
394  di->inbuf = NULL;
395  di->inbuflen = 0;
396  di->abs_cur_samplenum = 0;
397  di->thread_handle = NULL;
398  di->got_new_samples = FALSE;
399  di->handled_all_samples = FALSE;
400  di->want_wait_terminate = FALSE;
401  di->decoder_state = SRD_OK;
402 
403  /*
404  * Strictly speaking initialization of statically allocated
405  * condition and mutex variables (or variables allocated on the
406  * stack) is not required, but won't harm either. Explicitly
407  * running init() will better match subsequent clear() calls.
408  */
409  g_cond_init(&di->got_new_samples_cond);
410  g_cond_init(&di->handled_all_samples_cond);
411  g_mutex_init(&di->data_mutex);
412 
413  /* Instance takes input from a frontend by default. */
414  sess->di_list = g_slist_append(sess->di_list, di);
415  srd_dbg("Created new %s instance with ID %s.", decoder_id, di->inst_id);
416 
417  return di;
418 }
419 
420 static void srd_inst_join_decode_thread(struct srd_decoder_inst *di)
421 {
422  if (!di)
423  return;
424  if (!di->thread_handle)
425  return;
426 
427  srd_dbg("%s: Joining decoder thread.", di->inst_id);
428 
429  /*
430  * Terminate potentially running threads which still
431  * execute the decoder instance's decode() method.
432  */
433  srd_dbg("%s: Raising want_term, sending got_new.", di->inst_id);
434  g_mutex_lock(&di->data_mutex);
435  di->want_wait_terminate = TRUE;
436  g_cond_signal(&di->got_new_samples_cond);
437  g_mutex_unlock(&di->data_mutex);
438 
439  srd_dbg("%s: Running join().", di->inst_id);
440  (void)g_thread_join(di->thread_handle);
441  srd_dbg("%s: Call to join() done.", di->inst_id);
442  di->thread_handle = NULL;
443 
444  /*
445  * Reset condition and mutex variables, such that next
446  * operations on them will find them in a clean state.
447  */
448  g_cond_clear(&di->got_new_samples_cond);
449  g_cond_init(&di->got_new_samples_cond);
450  g_cond_clear(&di->handled_all_samples_cond);
451  g_cond_init(&di->handled_all_samples_cond);
452  g_mutex_clear(&di->data_mutex);
453  g_mutex_init(&di->data_mutex);
454 }
455 
456 static void srd_inst_reset_state(struct srd_decoder_inst *di)
457 {
458  if (!di)
459  return;
460 
461  srd_dbg("%s: Resetting decoder state.", di->inst_id);
462 
463  /* Reset internal state of the decoder. */
464  condition_list_free(di);
465  match_array_free(di);
466  di->abs_start_samplenum = 0;
467  di->abs_end_samplenum = 0;
468  di->inbuf = NULL;
469  di->inbuflen = 0;
470  di->abs_cur_samplenum = 0;
471  oldpins_array_free(di);
472  di->got_new_samples = FALSE;
473  di->handled_all_samples = FALSE;
474  di->want_wait_terminate = FALSE;
475  di->decoder_state = SRD_OK;
476  /* Conditions and mutex got reset after joining the thread. */
477 }
478 
479 /**
480  * Stack a decoder instance on top of another.
481  *
482  * @param sess The session holding the protocol decoder instances.
483  * Must not be NULL.
484  * @param di_bottom The instance on top of which di_top will be stacked.
485  * @param di_top The instance to go on top.
486  *
487  * @return SRD_OK upon success, a (negative) error code otherwise.
488  *
489  * @since 0.3.0
490  */
491 SRD_API int srd_inst_stack(struct srd_session *sess,
492  struct srd_decoder_inst *di_bottom,
493  struct srd_decoder_inst *di_top)
494 {
495  if (!sess)
496  return SRD_ERR_ARG;
497 
498  if (!di_bottom || !di_top) {
499  srd_err("Invalid from/to instance pair.");
500  return SRD_ERR_ARG;
501  }
502 
503  if (g_slist_find(sess->di_list, di_top)) {
504  /* Remove from the unstacked list. */
505  sess->di_list = g_slist_remove(sess->di_list, di_top);
506  }
507 
508  /* Stack on top of source di. */
509  di_bottom->next_di = g_slist_append(di_bottom->next_di, di_top);
510 
511  srd_dbg("Stacked %s onto %s.", di_top->inst_id, di_bottom->inst_id);
512 
513  return SRD_OK;
514 }
515 
516 /**
517  * Search a decoder instance and its stack for instance ID.
518  *
519  * @param[in] inst_id ID to search for.
520  * @param[in] stack A decoder instance, potentially with stacked instances.
521  *
522  * @return The matching instance, or NULL.
523  */
524 static struct srd_decoder_inst *srd_inst_find_by_id_stack(const char *inst_id,
525  struct srd_decoder_inst *stack)
526 {
527  const GSList *l;
528  struct srd_decoder_inst *tmp, *di;
529 
530  if (!strcmp(stack->inst_id, inst_id))
531  return stack;
532 
533  /* Otherwise, look recursively in our stack. */
534  di = NULL;
535  if (stack->next_di) {
536  for (l = stack->next_di; l; l = l->next) {
537  tmp = l->data;
538  if (!strcmp(tmp->inst_id, inst_id)) {
539  di = tmp;
540  break;
541  }
542  }
543  }
544 
545  return di;
546 }
547 
548 /**
549  * Find a decoder instance by its instance ID.
550  *
551  * This will recurse to find the instance anywhere in the stack tree of the
552  * given session.
553  *
554  * @param sess The session holding the protocol decoder instance.
555  * Must not be NULL.
556  * @param inst_id The instance ID to be found.
557  *
558  * @return Pointer to struct srd_decoder_inst, or NULL if not found.
559  *
560  * @since 0.3.0
561  */
562 SRD_API struct srd_decoder_inst *srd_inst_find_by_id(struct srd_session *sess,
563  const char *inst_id)
564 {
565  GSList *l;
566  struct srd_decoder_inst *tmp, *di;
567 
568  if (!sess)
569  return NULL;
570 
571  di = NULL;
572  for (l = sess->di_list; l; l = l->next) {
573  tmp = l->data;
574  if ((di = srd_inst_find_by_id_stack(inst_id, tmp)) != NULL)
575  break;
576  }
577 
578  return di;
579 }
580 
581 /**
582  * Set the list of initial (assumed) pin values.
583  *
584  * @param di Decoder instance to use. Must not be NULL.
585  * @param initial_pins A GArray of uint8_t values. Must not be NULL.
586  *
587  * @since 0.5.0
588  */
589 SRD_API int srd_inst_initial_pins_set_all(struct srd_decoder_inst *di, GArray *initial_pins)
590 {
591  int i;
592  GString *s;
593 
594  if (!di) {
595  srd_err("Invalid decoder instance.");
596  return SRD_ERR_ARG;
597  }
598 
599  if (!initial_pins)
600  return SRD_ERR_ARG;
601 
602  if (initial_pins->len != (guint)di->dec_num_channels) {
603  srd_err("Incorrect number of channels (need %d, got %d).",
604  di->dec_num_channels, initial_pins->len);
605  return SRD_ERR_ARG;
606  }
607 
608  /* Sanity-check initial pin state values. */
609  for (i = 0; i < di->dec_num_channels; i++) {
610  if (initial_pins->data[i] <= 2)
611  continue;
612  srd_err("Invalid initial channel %d pin state: %d.",
613  i, initial_pins->data[i]);
614  return SRD_ERR_ARG;
615  }
616 
617  s = g_string_sized_new(100);
618  oldpins_array_seed(di);
619  for (i = 0; i < di->dec_num_channels; i++) {
620  di->old_pins_array->data[i] = initial_pins->data[i];
621  g_string_append_printf(s, "%d, ", di->old_pins_array->data[i]);
622  }
623  s = g_string_truncate(s, s->len - 2);
624  srd_dbg("Initial pins: %s.", s->str);
625  g_string_free(s, TRUE);
626 
627  return SRD_OK;
628 }
629 
630 /** @private */
631 SRD_PRIV void oldpins_array_seed(struct srd_decoder_inst *di)
632 {
633  size_t count;
634  GArray *arr;
635 
636  if (!di)
637  return;
638  if (di->old_pins_array)
639  return;
640 
641  srd_dbg("%s: Seeding old pins, %s().", di->inst_id, __func__);
642  count = di->dec_num_channels;
643  arr = g_array_sized_new(FALSE, TRUE, sizeof(uint8_t), count);
644  g_array_set_size(arr, count);
645  memset(arr->data, SRD_INITIAL_PIN_SAME_AS_SAMPLE0, count);
646  di->old_pins_array = arr;
647 }
648 
649 /** @private */
650 SRD_PRIV void oldpins_array_free(struct srd_decoder_inst *di)
651 {
652  if (!di)
653  return;
654  if (!di->old_pins_array)
655  return;
656 
657  srd_dbg("%s: Releasing initial pin state.", di->inst_id);
658 
659  g_array_free(di->old_pins_array, TRUE);
660  di->old_pins_array = NULL;
661 }
662 
663 /** @private */
664 SRD_PRIV int srd_inst_start(struct srd_decoder_inst *di)
665 {
666  PyObject *py_res;
667  GSList *l;
668  struct srd_decoder_inst *next_di;
669  int ret;
670  PyGILState_STATE gstate;
671 
672  srd_dbg("Calling start() method on protocol decoder instance %s.",
673  di->inst_id);
674 
675  gstate = PyGILState_Ensure();
676 
677  /* Run self.start(). */
678  if (!(py_res = PyObject_CallMethod(di->py_inst, "start", NULL))) {
679  srd_exception_catch("Protocol decoder instance %s",
680  di->inst_id);
681  PyGILState_Release(gstate);
682  return SRD_ERR_PYTHON;
683  }
684  Py_DecRef(py_res);
685 
686  /* Set self.samplenum to 0. */
687  PyObject_SetAttrString(di->py_inst, "samplenum", PyLong_FromLong(0));
688 
689  /* Set self.matched to None. */
690  PyObject_SetAttrString(di->py_inst, "matched", Py_None);
691 
692  PyGILState_Release(gstate);
693 
694  /* Start all the PDs stacked on top of this one. */
695  for (l = di->next_di; l; l = l->next) {
696  next_di = l->data;
697  if ((ret = srd_inst_start(next_di)) != SRD_OK)
698  return ret;
699  }
700 
701  return SRD_OK;
702 }
703 
704 /**
705  * Check whether the specified sample matches the specified term.
706  *
707  * In the case of SRD_TERM_SKIP, this function can modify
708  * term->num_samples_already_skipped.
709  *
710  * @param old_sample The value of the previous sample (0/1).
711  * @param sample The value of the current sample (0/1).
712  * @param term The term that should be checked for a match. Must not be NULL.
713  *
714  * @retval TRUE The current sample matches the specified term.
715  * @retval FALSE The current sample doesn't match the specified term, or an
716  * invalid term was provided.
717  *
718  * @private
719  */
720 __attribute__((always_inline))
721 static inline gboolean sample_matches(uint8_t old_sample, uint8_t sample, struct srd_term *term)
722 {
723  /* Caller ensures term != NULL. */
724 
725  switch (term->type) {
726  case SRD_TERM_HIGH:
727  if (sample == 1)
728  return TRUE;
729  break;
730  case SRD_TERM_LOW:
731  if (sample == 0)
732  return TRUE;
733  break;
734  case SRD_TERM_RISING_EDGE:
735  if (old_sample == 0 && sample == 1)
736  return TRUE;
737  break;
738  case SRD_TERM_FALLING_EDGE:
739  if (old_sample == 1 && sample == 0)
740  return TRUE;
741  break;
742  case SRD_TERM_EITHER_EDGE:
743  if ((old_sample == 1 && sample == 0) || (old_sample == 0 && sample == 1))
744  return TRUE;
745  break;
746  case SRD_TERM_NO_EDGE:
747  if ((old_sample == 0 && sample == 0) || (old_sample == 1 && sample == 1))
748  return TRUE;
749  break;
750  case SRD_TERM_SKIP:
751  if (term->num_samples_already_skipped == term->num_samples_to_skip)
752  return TRUE;
753  term->num_samples_already_skipped++;
754  break;
755  default:
756  srd_err("Unknown term type %d.", term->type);
757  break;
758  }
759 
760  return FALSE;
761 }
762 
763 /** @private */
764 SRD_PRIV void match_array_free(struct srd_decoder_inst *di)
765 {
766  if (!di || !di->match_array)
767  return;
768 
769  g_array_free(di->match_array, TRUE);
770  di->match_array = NULL;
771 }
772 
773 /** @private */
774 SRD_PRIV void condition_list_free(struct srd_decoder_inst *di)
775 {
776  GSList *l, *ll;
777 
778  if (!di)
779  return;
780 
781  for (l = di->condition_list; l; l = l->next) {
782  ll = l->data;
783  if (ll)
784  g_slist_free_full(ll, g_free);
785  }
786 
787  di->condition_list = NULL;
788 }
789 
790 static gboolean have_non_null_conds(const struct srd_decoder_inst *di)
791 {
792  GSList *l, *cond;
793 
794  if (!di)
795  return FALSE;
796 
797  for (l = di->condition_list; l; l = l->next) {
798  cond = l->data;
799  if (cond)
800  return TRUE;
801  }
802 
803  return FALSE;
804 }
805 
806 static void update_old_pins_array(struct srd_decoder_inst *di,
807  const uint8_t *sample_pos)
808 {
809  uint8_t sample;
810  int i, byte_offset, bit_offset;
811 
812  if (!di || !di->dec_channelmap || !sample_pos)
813  return;
814 
815  oldpins_array_seed(di);
816  for (i = 0; i < di->dec_num_channels; i++) {
817  byte_offset = di->dec_channelmap[i] / 8;
818  bit_offset = di->dec_channelmap[i] % 8;
819  sample = *(sample_pos + byte_offset) & (1 << bit_offset) ? 1 : 0;
820  di->old_pins_array->data[i] = sample;
821  }
822 }
823 
824 static void update_old_pins_array_initial_pins(struct srd_decoder_inst *di)
825 {
826  uint8_t sample;
827  int i, byte_offset, bit_offset;
828  const uint8_t *sample_pos;
829 
830  if (!di || !di->dec_channelmap)
831  return;
832 
833  sample_pos = di->inbuf + ((di->abs_cur_samplenum - di->abs_start_samplenum) * di->data_unitsize);
834 
835  oldpins_array_seed(di);
836  for (i = 0; i < di->dec_num_channels; i++) {
838  continue;
839  byte_offset = di->dec_channelmap[i] / 8;
840  bit_offset = di->dec_channelmap[i] % 8;
841  sample = *(sample_pos + byte_offset) & (1 << bit_offset) ? 1 : 0;
842  di->old_pins_array->data[i] = sample;
843  }
844 }
845 
846 static gboolean term_matches(const struct srd_decoder_inst *di,
847  struct srd_term *term, const uint8_t *sample_pos)
848 {
849  uint8_t old_sample, sample;
850  int byte_offset, bit_offset, ch;
851 
852  /* Caller ensures di, di->dec_channelmap, term, sample_pos != NULL. */
853 
854  if (term->type == SRD_TERM_SKIP)
855  return sample_matches(0, 0, term);
856 
857  ch = term->channel;
858  byte_offset = di->dec_channelmap[ch] / 8;
859  bit_offset = di->dec_channelmap[ch] % 8;
860  sample = *(sample_pos + byte_offset) & (1 << bit_offset) ? 1 : 0;
861  old_sample = di->old_pins_array->data[ch];
862 
863  return sample_matches(old_sample, sample, term);
864 }
865 
866 static gboolean all_terms_match(const struct srd_decoder_inst *di,
867  const GSList *cond, const uint8_t *sample_pos)
868 {
869  const GSList *l;
870  struct srd_term *term;
871 
872  /* Caller ensures di, cond, sample_pos != NULL. */
873 
874  for (l = cond; l; l = l->next) {
875  term = l->data;
876  if (!term_matches(di, term, sample_pos))
877  return FALSE;
878  }
879 
880  return TRUE;
881 }
882 
883 static gboolean at_least_one_condition_matched(
884  const struct srd_decoder_inst *di, unsigned int num_conditions)
885 {
886  unsigned int i;
887 
888  /* Caller ensures di != NULL. */
889 
890  for (i = 0; i < num_conditions; i++) {
891  if (di->match_array->data[i])
892  return TRUE;
893  }
894 
895  return FALSE;
896 }
897 
898 static gboolean find_match(struct srd_decoder_inst *di)
899 {
900  uint64_t i, j, num_samples_to_process;
901  GSList *l, *cond;
902  const uint8_t *sample_pos;
903  unsigned int num_conditions;
904 
905  /* Caller ensures di != NULL. */
906 
907  /* Check whether the condition list is NULL/empty. */
908  if (!di->condition_list) {
909  srd_dbg("NULL/empty condition list, automatic match.");
910  return TRUE;
911  }
912 
913  /* Check whether we have any non-NULL conditions. */
914  if (!have_non_null_conds(di)) {
915  srd_dbg("Only NULL conditions in list, automatic match.");
916  return TRUE;
917  }
918 
919  num_samples_to_process = di->abs_end_samplenum - di->abs_cur_samplenum;
920  num_conditions = g_slist_length(di->condition_list);
921 
922  /* di->match_array is NULL here. Create a new GArray. */
923  di->match_array = g_array_sized_new(FALSE, TRUE, sizeof(gboolean), num_conditions);
924  g_array_set_size(di->match_array, num_conditions);
925 
926  /* Sample 0: Set di->old_pins_array for SRD_INITIAL_PIN_SAME_AS_SAMPLE0 pins. */
927  if (di->abs_cur_samplenum == 0)
928  update_old_pins_array_initial_pins(di);
929 
930  for (i = 0; i < num_samples_to_process; i++, (di->abs_cur_samplenum)++) {
931 
932  sample_pos = di->inbuf + ((di->abs_cur_samplenum - di->abs_start_samplenum) * di->data_unitsize);
933 
934  /* Check whether the current sample matches at least one of the conditions (logical OR). */
935  /* IMPORTANT: We need to check all conditions, even if there was a match already! */
936  for (l = di->condition_list, j = 0; l; l = l->next, j++) {
937  cond = l->data;
938  if (!cond)
939  continue;
940  /* All terms in 'cond' must match (logical AND). */
941  di->match_array->data[j] = all_terms_match(di, cond, sample_pos);
942  }
943 
944  update_old_pins_array(di, sample_pos);
945 
946  /* If at least one condition matched we're done. */
947  if (at_least_one_condition_matched(di, num_conditions))
948  return TRUE;
949  }
950 
951  return FALSE;
952 }
953 
954 /**
955  * Process available samples and check if they match the defined conditions.
956  *
957  * This function returns if there is an error, or when a match is found, or
958  * when all samples have been processed (whether a match was found or not).
959  * This function immediately terminates when the decoder's wait() method
960  * invocation shall get terminated.
961  *
962  * @param di The decoder instance to use. Must not be NULL.
963  * @param found_match Will be set to TRUE if at least one condition matched,
964  * FALSE otherwise. Must not be NULL.
965  *
966  * @retval SRD_OK No errors occured, see found_match for the result.
967  * @retval SRD_ERR_ARG Invalid arguments.
968  *
969  * @private
970  */
971 SRD_PRIV int process_samples_until_condition_match(struct srd_decoder_inst *di, gboolean *found_match)
972 {
973  if (!di || !found_match)
974  return SRD_ERR_ARG;
975 
976  *found_match = FALSE;
977  if (di->want_wait_terminate)
978  return SRD_OK;
979 
980  /* Check if any of the current condition(s) match. */
981  while (TRUE) {
982  /* Feed the (next chunk of the) buffer to find_match(). */
983  *found_match = find_match(di);
984 
985  /* Did we handle all samples yet? */
986  if (di->abs_cur_samplenum >= di->abs_end_samplenum) {
987  srd_dbg("Done, handled all samples (abs cur %" PRIu64
988  " / abs end %" PRIu64 ").",
990  return SRD_OK;
991  }
992 
993  /* If we didn't find a match, continue looking. */
994  if (!(*found_match))
995  continue;
996 
997  /* At least one condition matched, return. */
998  return SRD_OK;
999  }
1000 
1001  return SRD_OK;
1002 }
1003 
1004 /**
1005  * Worker thread (per PD-stack).
1006  *
1007  * @param data Pointer to the lowest-level PD's device instance.
1008  * Must not be NULL.
1009  *
1010  * @return NULL if there was an error.
1011  */
1012 static gpointer di_thread(gpointer data)
1013 {
1014  PyObject *py_res;
1015  struct srd_decoder_inst *di;
1016  int wanted_term;
1017  PyGILState_STATE gstate;
1018 
1019  if (!data)
1020  return NULL;
1021 
1022  di = data;
1023 
1024  srd_dbg("%s: Starting thread routine for decoder.", di->inst_id);
1025 
1026  gstate = PyGILState_Ensure();
1027 
1028  /*
1029  * Call self.decode(). Only returns if the PD throws an exception.
1030  * "Regular" termination of the decode() method is not expected.
1031  */
1032  Py_IncRef(di->py_inst);
1033  srd_dbg("%s: Calling decode() method.", di->inst_id);
1034  py_res = PyObject_CallMethod(di->py_inst, "decode", NULL);
1035  srd_dbg("%s: decode() method terminated.", di->inst_id);
1036 
1037  if (!py_res)
1038  di->decoder_state = SRD_ERR;
1039 
1040  /*
1041  * Make sure to unblock potentially pending srd_inst_decode()
1042  * calls in application threads after the decode() method might
1043  * have terminated, while it neither has processed sample data
1044  * nor has terminated upon request. This happens e.g. when "need
1045  * a samplerate to decode" exception is thrown.
1046  */
1047  g_mutex_lock(&di->data_mutex);
1048  wanted_term = di->want_wait_terminate;
1049  di->want_wait_terminate = TRUE;
1050  di->handled_all_samples = TRUE;
1051  g_cond_signal(&di->handled_all_samples_cond);
1052  g_mutex_unlock(&di->data_mutex);
1053 
1054  /*
1055  * Check for the termination cause of the decode() method.
1056  * Though this is mostly for information.
1057  */
1058  if (!py_res && wanted_term) {
1059  /*
1060  * Silently ignore errors upon return from decode() calls
1061  * when termination was requested. Terminate the thread
1062  * which executed this instance's decode() logic.
1063  */
1064  srd_dbg("%s: Thread done (!res, want_term).", di->inst_id);
1065  PyErr_Clear();
1066  PyGILState_Release(gstate);
1067  return NULL;
1068  }
1069  if (!py_res) {
1070  /*
1071  * The decode() invocation terminated unexpectedly. Have
1072  * the back trace printed, and terminate the thread which
1073  * executed the decode() method.
1074  */
1075  srd_dbg("%s: decode() terminated unrequested.", di->inst_id);
1076  srd_exception_catch("Protocol decoder instance %s: ", di->inst_id);
1077  srd_dbg("%s: Thread done (!res, !want_term).", di->inst_id);
1078  PyGILState_Release(gstate);
1079  return NULL;
1080  }
1081 
1082  /*
1083  * TODO: By design the decode() method is not supposed to terminate.
1084  * Nevertheless we have the thread joined, and srd backend calls to
1085  * decode() will re-start another thread transparently.
1086  */
1087  srd_dbg("%s: decode() terminated (req %d).", di->inst_id, wanted_term);
1088  Py_DecRef(py_res);
1089  PyErr_Clear();
1090 
1091  PyGILState_Release(gstate);
1092 
1093  srd_dbg("%s: Thread done (with res).", di->inst_id);
1094 
1095  return NULL;
1096 }
1097 
1098 /**
1099  * Decode a chunk of samples.
1100  *
1101  * The calls to this function must provide the samples that shall be
1102  * used by the protocol decoder
1103  * - in the correct order ([...]5, 6, 4, 7, 8[...] is a bug),
1104  * - starting from sample zero (2, 3, 4, 5, 6[...] is a bug),
1105  * - consecutively, with no gaps (0, 1, 2, 4, 5[...] is a bug).
1106  *
1107  * The start- and end-sample numbers are absolute sample numbers (relative
1108  * to the start of the whole capture/file/stream), i.e. they are not relative
1109  * sample numbers within the chunk specified by 'inbuf' and 'inbuflen'.
1110  *
1111  * Correct example (4096 samples total, 4 chunks @ 1024 samples each):
1112  * srd_inst_decode(di, 0, 1024, inbuf, 1024, 1);
1113  * srd_inst_decode(di, 1024, 2048, inbuf, 1024, 1);
1114  * srd_inst_decode(di, 2048, 3072, inbuf, 1024, 1);
1115  * srd_inst_decode(di, 3072, 4096, inbuf, 1024, 1);
1116  *
1117  * The chunk size ('inbuflen') can be arbitrary and can differ between calls.
1118  *
1119  * Correct example (4096 samples total, 7 chunks @ various samples each):
1120  * srd_inst_decode(di, 0, 1024, inbuf, 1024, 1);
1121  * srd_inst_decode(di, 1024, 1124, inbuf, 100, 1);
1122  * srd_inst_decode(di, 1124, 1424, inbuf, 300, 1);
1123  * srd_inst_decode(di, 1424, 1643, inbuf, 219, 1);
1124  * srd_inst_decode(di, 1643, 2048, inbuf, 405, 1);
1125  * srd_inst_decode(di, 2048, 3072, inbuf, 1024, 1);
1126  * srd_inst_decode(di, 3072, 4096, inbuf, 1024, 1);
1127  *
1128  * INCORRECT example (4096 samples total, 4 chunks @ 1024 samples each, but
1129  * the start- and end-samplenumbers are not absolute):
1130  * srd_inst_decode(di, 0, 1024, inbuf, 1024, 1);
1131  * srd_inst_decode(di, 0, 1024, inbuf, 1024, 1);
1132  * srd_inst_decode(di, 0, 1024, inbuf, 1024, 1);
1133  * srd_inst_decode(di, 0, 1024, inbuf, 1024, 1);
1134  *
1135  * @param di The decoder instance to call. Must not be NULL.
1136  * @param abs_start_samplenum The absolute starting sample number for the
1137  * buffer's sample set, relative to the start of capture.
1138  * @param abs_end_samplenum The absolute ending sample number for the
1139  * buffer's sample set, relative to the start of capture.
1140  * @param inbuf The buffer to decode. Must not be NULL.
1141  * @param inbuflen Length of the buffer. Must be > 0.
1142  * @param unitsize The number of bytes per sample. Must be > 0.
1143  *
1144  * @return SRD_OK upon success, a (negative) error code otherwise.
1145  *
1146  * @private
1147  */
1148 SRD_PRIV int srd_inst_decode(struct srd_decoder_inst *di,
1149  uint64_t abs_start_samplenum, uint64_t abs_end_samplenum,
1150  const uint8_t *inbuf, uint64_t inbuflen, uint64_t unitsize)
1151 {
1152  /* Return an error upon unusable input. */
1153  if (!di) {
1154  srd_dbg("empty decoder instance");
1155  return SRD_ERR_ARG;
1156  }
1157  if (!inbuf) {
1158  srd_dbg("NULL buffer pointer");
1159  return SRD_ERR_ARG;
1160  }
1161  if (inbuflen == 0) {
1162  srd_dbg("empty buffer");
1163  return SRD_ERR_ARG;
1164  }
1165  if (unitsize == 0) {
1166  srd_dbg("unitsize 0");
1167  return SRD_ERR_ARG;
1168  }
1169 
1172  srd_dbg("Incorrect sample numbers: start=%" PRIu64 ", cur=%"
1173  PRIu64 ", end=%" PRIu64 ".", abs_start_samplenum,
1175  return SRD_ERR_ARG;
1176  }
1177 
1178  di->data_unitsize = unitsize;
1179 
1180  srd_dbg("Decoding: abs start sample %" PRIu64 ", abs end sample %"
1181  PRIu64 " (%" PRIu64 " samples, %" PRIu64 " bytes, unitsize = "
1182  "%d), instance %s.", abs_start_samplenum, abs_end_samplenum,
1184  di->inst_id);
1185 
1186  /* If this is the first call, start the worker thread. */
1187  if (!di->thread_handle) {
1188  srd_dbg("No worker thread for this decoder stack "
1189  "exists yet, creating one: %s.", di->inst_id);
1190  di->thread_handle = g_thread_new(di->inst_id,
1191  di_thread, di);
1192  }
1193 
1194  /* Push the new sample chunk to the worker thread. */
1195  g_mutex_lock(&di->data_mutex);
1198  di->inbuf = inbuf;
1199  di->inbuflen = inbuflen;
1200  di->got_new_samples = TRUE;
1201  di->handled_all_samples = FALSE;
1202 
1203  /* Signal the thread that we have new data. */
1204  g_cond_signal(&di->got_new_samples_cond);
1205  g_mutex_unlock(&di->data_mutex);
1206 
1207  /* When all samples in this chunk were handled, return. */
1208  g_mutex_lock(&di->data_mutex);
1209  while (!di->handled_all_samples && !di->want_wait_terminate)
1210  g_cond_wait(&di->handled_all_samples_cond, &di->data_mutex);
1211  g_mutex_unlock(&di->data_mutex);
1212 
1213  if (di->want_wait_terminate)
1214  return SRD_ERR_TERM_REQ;
1215 
1216  return SRD_OK;
1217 }
1218 
1219 /**
1220  * Terminate current decoder work, prepare for re-use on new input data.
1221  *
1222  * Terminates all decoder operations in the specified decoder instance
1223  * and the instances stacked on top of it. Resets internal state such
1224  * that the previously constructed stack can process new input data that
1225  * is not related to previously processed input data. This avoids the
1226  * expensive and complex re-construction of decoder stacks.
1227  *
1228  * Callers are expected to follow up with start, metadata, and decode
1229  * calls like they would for newly constructed decoder stacks.
1230  *
1231  * @param di The decoder instance to call. Must not be NULL.
1232  *
1233  * @return SRD_OK upon success, a (negative) error code otherwise.
1234  *
1235  * @private
1236  */
1237 SRD_PRIV int srd_inst_terminate_reset(struct srd_decoder_inst *di)
1238 {
1239  PyGILState_STATE gstate;
1240  PyObject *py_ret;
1241  GSList *l;
1242  int ret;
1243 
1244  if (!di)
1245  return SRD_ERR_ARG;
1246 
1247  /*
1248  * Request termination and wait for previously initiated
1249  * background operation to finish. Reset internal state, but
1250  * do not start releasing resources yet. This shall result in
1251  * decoders' state just like after creation. This block handles
1252  * the C language library side.
1253  */
1254  srd_dbg("Terminating instance %s", di->inst_id);
1255  srd_inst_join_decode_thread(di);
1256  srd_inst_reset_state(di);
1257 
1258  /*
1259  * Have the Python side's .reset() method executed (if the PD
1260  * implements it). It's assumed that .reset() assigns variables
1261  * very much like __init__() used to do in the past. Thus memory
1262  * that was allocated in previous calls gets released by Python
1263  * as it's not referenced any longer.
1264  */
1265  gstate = PyGILState_Ensure();
1266  if (PyObject_HasAttrString(di->py_inst, "reset")) {
1267  srd_dbg("Calling .reset() of instance %s", di->inst_id);
1268  py_ret = PyObject_CallMethod(di->py_inst, "reset", NULL);
1269  Py_XDECREF(py_ret);
1270  }
1271  PyGILState_Release(gstate);
1272 
1273  /* Pass the "restart" request to all stacked decoders. */
1274  for (l = di->next_di; l; l = l->next) {
1275  ret = srd_inst_terminate_reset(l->data);
1276  if (ret != SRD_OK)
1277  return ret;
1278  }
1279 
1280  return di->decoder_state;
1281 }
1282 
1283 /** @private */
1284 SRD_PRIV void srd_inst_free(struct srd_decoder_inst *di)
1285 {
1286  GSList *l;
1287  struct srd_pd_output *pdo;
1288  PyGILState_STATE gstate;
1289 
1290  srd_dbg("Freeing instance %s.", di->inst_id);
1291 
1292  srd_inst_join_decode_thread(di);
1293 
1294  srd_inst_reset_state(di);
1295 
1296  gstate = PyGILState_Ensure();
1297  Py_DecRef(di->py_inst);
1298  PyGILState_Release(gstate);
1299 
1300  g_free(di->inst_id);
1301  g_free(di->dec_channelmap);
1302  g_free(di->channel_samples);
1303  g_slist_free(di->next_di);
1304  for (l = di->pd_output; l; l = l->next) {
1305  pdo = l->data;
1306  g_free(pdo->proto_id);
1307  g_free(pdo);
1308  }
1309  g_slist_free(di->pd_output);
1310  g_free(di);
1311 }
1312 
1313 /** @private */
1314 SRD_PRIV void srd_inst_free_all(struct srd_session *sess)
1315 {
1316  if (!sess)
1317  return;
1318 
1319  g_slist_free_full(sess->di_list, (GDestroyNotify)srd_inst_free);
1320 }
1321 
1322 /** @} */
No error.
struct srd_decoder * decoder
Function argument error.
GThread * thread_handle
Handle for this PD stack&#39;s worker thread.
struct srd_decoder * srd_decoder_get_by_id(const char *id)
Get the decoder with the specified ID.
Definition: decoder.c:89
uint64_t abs_end_samplenum
Absolute end sample number.
struct srd_session * sess
int srd_inst_option_set(struct srd_decoder_inst *di, GHashTable *options)
Set one or more options in a decoder instance.
Definition: instance.c:66
gboolean want_wait_terminate
Requests termination of wait() and decode().
gboolean got_new_samples
Indicates whether new samples are available for processing.
uint64_t inbuflen
Length (in bytes) of the input sample buffer.
int order
The index of the channel, i.e.
Structure which contains information about one protocol decoder channel.
Termination requested.
#define SRD_API
const uint8_t * inbuf
Pointer to the buffer/chunk of input samples.
GArray * match_array
Array of booleans denoting which conditions matched.
Generic/unspecified error.
int decoder_state
Indicates the current state of the decoder stack.
GCond handled_all_samples_cond
GSList * opt_channels
List of optional channels for this decoder.
struct srd_decoder_inst * di
void * py_dec
sigrokdecode.Decoder class.
uint64_t abs_cur_samplenum
Absolute current samplenumber.
char * id
The ID of the channel.
GArray * old_pins_array
Array of "old" (previous sample) pin values.
The public libsigrokdecode header file to be used by frontends.
uint64_t abs_start_samplenum
Absolute start sample number.
GSList * condition_list
List of conditions a PD wants to wait for.
int srd_inst_stack(struct srd_session *sess, struct srd_decoder_inst *di_bottom, struct srd_decoder_inst *di_top)
Stack a decoder instance on top of another.
Definition: instance.c:491
char * name
The (short) decoder name.
GSList * options
List of decoder options.
struct srd_decoder_inst * srd_inst_find_by_id(struct srd_session *sess, const char *inst_id)
Find a decoder instance by its instance ID.
Definition: instance.c:562
gboolean handled_all_samples
Indicates whether the worker thread has handled all samples.
#define SRD_PRIV
GSList * channels
List of channels required by this decoder.
struct srd_decoder_inst * srd_inst_new(struct srd_session *sess, const char *decoder_id, GHashTable *options)
Create a new protocol decoder instance.
Definition: instance.c:307
int srd_inst_channel_set_all(struct srd_decoder_inst *di, GHashTable *new_channels)
Set all channels in a decoder instance.
Definition: instance.c:202
int srd_inst_initial_pins_set_all(struct srd_decoder_inst *di, GArray *initial_pins)
Set the list of initial (assumed) pin values.
Definition: instance.c:589
Python C API error.
uint8_t * channel_samples