fecdec_filter: Simplify clear_group().
[paraslash.git] / fecdec_filter.c
1 /*
2 * Copyright (C) 2009-2010 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file fecdec_filter.c A filter that fec-decodes an audio stream. */
8
9 #include <regex.h>
10 #include <stdbool.h>
11
12 #include <dirent.h>
13 #include "para.h"
14 #include "error.h"
15 #include "list.h"
16 #include "sched.h"
17 #include "ggo.h"
18 #include "buffer_tree.h"
19 #include "filter.h"
20 #include "string.h"
21 #include "portable_io.h"
22 #include "fec.h"
23 #include "fd.h"
24
25 /**
26 * How many FEC groups to store in memory.
27 *
28 * Packet reordering requires to keep more than one FEC group in memory because
29 * slices belonging to the next FEC group may arrive before the current FEC group
30 * is complete.
31 */
32 #define NUM_FEC_GROUPS 3
33
34 /** Data read from the header of a slice. */
35 struct fec_header {
36 /** Total number of slices in this group. */
37 uint8_t slices_per_group;
38 /** Number of slices needed to start decoding. */
39 uint8_t data_slices_per_group;
40 /** Size of the ogg vorbis/wma header (zero for mp3, aac). */
41 uint32_t audio_header_size;
42 /** Number of the FEC group this slice belongs to. */
43 uint32_t group_num;
44 /** Size of the data in this FEC group. */
45 uint32_t group_bytes;
46 /** Number of this slice in the group. */
47 uint8_t slice_num;
48 /** Used data bytes of this slice. */
49 uint16_t slice_bytes;
50 /** Non-zero if this group is the beginning of the stream. */
51 uint8_t bos;
52 /** Non-zero if this stream embedds audio headers into fec groups. */
53 uint8_t header_stream;
54 };
55
56 /**
57 * The status of one partially received FEC group.
58 */
59 struct fecdec_group {
60 /** The header read from the last slice. */
61 struct fec_header h;
62 /** How many slices received so far. */
63 int num_received_slices;
64 /** The size of the \a idx and the \a data arrays below. */
65 int num_slices;
66 /** Array of indices of the received slices. */
67 int *idx;
68 /** Content of the received slices. */
69 unsigned char **data;
70 };
71
72 /**
73 * Data private to the fecdec filter.
74 */
75 struct private_fecdec_data {
76 /** Used by the fec core code. */
77 struct fec_parms *fec;
78 /** Keeps track of what was received so far. */
79 struct fecdec_group groups[NUM_FEC_GROUPS];
80 /** Whether an audio file header was already received. */
81 int have_header;
82 /** Points to the first received group. */
83 struct fecdec_group *first_complete_group;
84 struct btr_pool *btrp;
85 };
86
87 /** Iterate over all fecdec groups. */
88 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
89 (g) < (d)->groups + NUM_FEC_GROUPS; (g)++)
90
91 static int group_complete(struct fecdec_group *fg)
92 {
93 return fg->num_received_slices >= fg->h.data_slices_per_group;
94 }
95
96 static int group_empty(struct fecdec_group *fg)
97 {
98 return fg->num_received_slices == 0;
99 }
100
101 static void clear_group(struct fecdec_group *fg)
102 {
103 int i;
104
105 for (i = 0; i < fg->num_slices; i++)
106 free(fg->data[i]);
107 free(fg->data);
108 free(fg->idx);
109 memset(fg, 0, sizeof(*fg));
110 }
111
112 static int find_group(struct fec_header *h,
113 struct private_fecdec_data *pfd, struct fecdec_group **result)
114 {
115 struct fecdec_group *fg;
116
117 FOR_EACH_FECDEC_GROUP(fg, pfd) {
118 if (fg->h.group_num != h->group_num)
119 continue;
120 if (fg->num_received_slices == 0)
121 goto success;
122 if (fg->h.slices_per_group != h->slices_per_group)
123 return -E_BAD_FEC_HEADER;
124 if (fg->h.data_slices_per_group != h->data_slices_per_group)
125 return -E_BAD_FEC_HEADER;
126 if (fg->h.group_bytes != h->group_bytes)
127 return -E_BAD_FEC_HEADER;
128 success:
129 *result = fg;
130 return 1;
131 }
132 return 0;
133 }
134
135 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
136 {
137 struct fecdec_group *fg;
138
139 FOR_EACH_FECDEC_GROUP(fg, pfd) {
140 if (fg->num_received_slices == 0)
141 return fg;
142 }
143 return NULL;
144 }
145
146 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
147 {
148 struct fecdec_group *fg;
149
150 FOR_EACH_FECDEC_GROUP(fg, pfd) {
151 if (!group_complete(fg))
152 continue;
153 /*
154 * Don't clear the first complete group if it has not yet been
155 * decoded.
156 */
157 if (fg == pfd->first_complete_group)
158 continue;
159 clear_group(fg);
160 return fg;
161 }
162 return NULL;
163 }
164
165 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
166 {
167 struct fecdec_group *fg, *oldest = NULL;
168
169 FOR_EACH_FECDEC_GROUP(fg, pfd) {
170 if (!oldest || oldest->h.group_num > fg->h.group_num)
171 oldest = fg;
172 }
173 if (!group_complete(oldest) && !group_empty(oldest))
174 PARA_WARNING_LOG("Clearing incomplete group %d "
175 "(contains %d slices)\n", oldest->h.group_num,
176 oldest->num_received_slices);
177 if (oldest == pfd->first_complete_group)
178 pfd->first_complete_group = NULL;
179 clear_group(oldest);
180 return oldest;
181 }
182
183 /* returns 1 if the group was found, 0 if not, negative on errors */
184 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
185 struct fecdec_group **result)
186 {
187 struct fecdec_group *fg;
188 int ret = find_group(h, pfd, &fg);
189
190 if (ret < 0)
191 return ret;
192 if (ret > 0) /* found group */
193 goto success;
194 /* group not found */
195 fg = find_unused_group(pfd);
196 if (fg)
197 goto success;
198 fg = try_to_free_group(pfd);
199 if (fg)
200 goto success;
201 fg = free_oldest_group(pfd);
202 ret = 0;
203 success:
204 fg->h = *h;
205 *result = fg;
206 return ret;
207 }
208
209 /*
210 * returns 1 if slice was added, zero otherwise (because the group was already
211 * complete). In any case the number of received slices is being increased by
212 * one.
213 */
214 static int add_slice(char *buf, struct fecdec_group *fg)
215 {
216 int r, slice_num;
217
218 if (group_complete(fg)) {
219 PARA_DEBUG_LOG("group %d complete, ignoring slice %d\n",
220 fg->h.group_num, fg->h.slice_num);
221 fg->num_received_slices++;
222 return 0;
223 }
224 slice_num = fg->h.slice_num;
225 if (fg->num_slices == 0) {
226 fg->num_slices = fg->h.slices_per_group;
227 fg->idx = para_malloc(fg->num_slices * sizeof(int));
228 fg->data = para_malloc(fg->num_slices * sizeof(unsigned char *));
229 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
230 }
231 r = fg->num_received_slices;
232 fg->idx[r] = slice_num;
233 fg->data[r] = para_malloc(fg->h.slice_bytes);
234 memcpy(fg->data[r], buf, fg->h.slice_bytes);
235 fg->num_received_slices++;
236 return 1;
237 }
238
239 /**
240 * The different states of a complete FEC group.
241 *
242 * Even if a FEC group has been received successfully, it probably can not be
243 * used right away because some streams (ogg, wma) need to receive an audio
244 * file header before decoding can start.
245 */
246 enum fec_group_usability {
247 /** Drop the group (because we did not receive the header yet). */
248 FEC_GROUP_UNUSABLE,
249 /** Use all data in the group. */
250 FEC_GROUP_USABLE,
251 /** Use the group, but drop its audio file header. */
252 FEC_GROUP_USABLE_SKIP_HEADER,
253 /** Use the group, including its header. */
254 FEC_GROUP_USABLE_WITH_HEADER
255 };
256
257 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
258 struct private_fecdec_data *pfd)
259 {
260 struct fec_header *h = &fg->h;
261
262 if (!h->header_stream)
263 return FEC_GROUP_USABLE;
264 if (pfd->have_header) {
265 if (h->audio_header_size)
266 return FEC_GROUP_USABLE_SKIP_HEADER;
267 return FEC_GROUP_USABLE;
268 }
269 if (fg->h.bos)
270 return FEC_GROUP_USABLE;
271 if (fg->h.audio_header_size)
272 return FEC_GROUP_USABLE_WITH_HEADER;
273 return FEC_GROUP_UNUSABLE;
274 }
275
276 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
277 {
278 int i, ret, sb = fg->h.slice_bytes;
279 size_t written, need;
280 struct private_fecdec_data *pfd = fn->private_data;
281 enum fec_group_usability u = group_is_usable(fg, pfd);
282 char *buf = NULL, *p;
283
284 if (u == FEC_GROUP_UNUSABLE) {
285 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
286 return 0;
287 }
288 PARA_DEBUG_LOG("decoding group %d (%d slices)\n", fg->h.group_num,
289 fg->h.data_slices_per_group);
290 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
291 if (ret < 0)
292 return ret;
293 pfd->have_header = 1;
294 i = 0;
295 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
296 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
297 / fg->h.slice_bytes;
298 PARA_DEBUG_LOG("skipping %d header slices\n", i);
299 }
300 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
301 fg->h.group_num, fg->h.group_bytes,
302 fg->h.data_slices_per_group * sb);
303 need = (fg->h.data_slices_per_group - i) * sb;
304 if (need > btr_pool_unused(pfd->btrp))
305 return -E_FECDEC_OVERRUN;
306 btr_pool_get_buffer(pfd->btrp, &buf);
307 p = buf;
308 if (u == FEC_GROUP_USABLE_WITH_HEADER) {
309 PARA_INFO_LOG("writing audio file header\n");
310 written = 0;
311 for (i = 0; i < fg->h.data_slices_per_group; i++) {
312 size_t n = sb;
313 if (written >= fg->h.audio_header_size)
314 break;
315 if (sb + written > fg->h.audio_header_size)
316 n = fg->h.audio_header_size - written;
317 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
318 written += n;
319 }
320 p += written;
321 }
322 written = 0;
323 for (; i < fg->h.data_slices_per_group; i++) {
324 size_t n = sb;
325 if (n + written > fg->h.group_bytes)
326 n = fg->h.group_bytes - written;
327 btr_copy(fg->data[i], n, pfd->btrp, fn->btrn);
328 written += n;
329 }
330 p += written;
331 return 0;
332 }
333
334 /**
335 * Read a fec header from a buffer.
336 *
337 * \param buf The buffer to write to.
338 * \param h The fec header to write.
339 */
340 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
341 {
342 uint32_t magic;
343
344 if (len < FEC_HEADER_SIZE)
345 return 0;
346 magic = read_u32(buf);
347 if (magic != FEC_MAGIC)
348 return -E_BAD_FEC_HEADER;
349 h->slices_per_group = read_u8(buf + 4);
350 h->data_slices_per_group = read_u8(buf + 5);
351 h->audio_header_size = read_u32(buf + 6);
352
353 h->group_num = read_u32(buf + 10);
354 h->group_bytes = read_u32(buf + 14);
355
356 h->slice_num = read_u8(buf + 18);
357 h->slice_bytes = read_u16(buf + 20);
358 h->bos = read_u8(buf + 22);
359 h->header_stream = read_u8(buf + 23);
360 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
361 return -E_FECDEC_EOF;
362 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
363 // h->group_num, h->slice_num, h->slices_per_group);
364 return 1;
365 }
366
367 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
368 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
369 struct filter_node *fn)
370 {
371 struct fecdec_group *fg;
372 int ret, k, n;
373 struct private_fecdec_data *pfd = fn->private_data;
374
375 if (h->slice_bytes > len) { /* can not use the thing, try to read more */
376 fn->min_iqs = h->slice_bytes + FEC_HEADER_SIZE;
377 return 0;
378 }
379 ret = get_group(h, pfd, &fg);
380 if (ret < 0)
381 return ret;
382 if (!add_slice(buf, fg)) /* group already complete */
383 return 1;
384 if (!group_complete(fg))
385 return 1;
386 /* this slice completed the group */
387 if (pfd->fec)
388 goto decode;
389 /* it's either the first or the second complete group */
390 if (!pfd->first_complete_group) { /* it's the first group */
391 enum fec_group_usability u = group_is_usable(fg, pfd);
392 assert(u != FEC_GROUP_USABLE_SKIP_HEADER);
393 if (u == FEC_GROUP_UNUSABLE) /* forget it */
394 return 1;
395 pfd->first_complete_group = fg; /* remember it */
396 return 1;
397 }
398 /* we have two complete groups, let's go */
399 k = h->data_slices_per_group;
400 n = h->slices_per_group;
401 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
402 ret = fec_new(k, n, &pfd->fec);
403 if (ret < 0)
404 return ret;
405 pfd->btrp = btr_pool_new("fecdec", 20 * k * h->slice_bytes);
406 /* decode and clear the first group */
407 ret = decode_group(pfd->first_complete_group, fn);
408 if (ret < 0)
409 return ret;
410 clear_group(pfd->first_complete_group);
411 pfd->first_complete_group = NULL;
412 decode:
413 ret = decode_group(fg, fn);
414 if (ret < 0)
415 return ret;
416 return 1;
417 }
418
419 static void fecdec_close(struct filter_node *fn)
420 {
421 struct private_fecdec_data *pfd = fn->private_data;
422 struct fecdec_group *fg;
423
424 FOR_EACH_FECDEC_GROUP(fg, pfd)
425 clear_group(fg);
426 fec_free(pfd->fec);
427 btr_pool_free(pfd->btrp);
428 free(fn->private_data);
429 fn->private_data = NULL;
430 }
431
432 static void fecdec_post_select(__a_unused struct sched *s, struct task *t)
433 {
434 struct filter_node *fn = container_of(t, struct filter_node, task);
435 struct btr_node *btrn = fn->btrn;
436 int ret;
437 struct fec_header h;
438 char *buf;
439 size_t len;
440
441 next_buffer:
442 ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
443 if (ret <= 0)
444 goto out;
445 btr_merge(btrn, fn->min_iqs);
446 len = btr_next_buffer(btrn, &buf);
447 ret = read_fec_header(buf, len, &h);
448 if (ret <= 0)
449 goto out;
450 ret = -E_BAD_SLICE_SIZE;
451 if (!h.slice_bytes)
452 goto out;
453 ret = -E_BAD_SLICE_NUM;
454 if (h.slice_num > h.slices_per_group)
455 goto out;
456 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
457 &h, fn);
458 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
459 if (ret <= 0)
460 goto out;
461 btr_consume(btrn, FEC_HEADER_SIZE + h.slice_bytes);
462 goto next_buffer;
463 out:
464 t->error = ret;
465 if (ret < 0)
466 btr_remove_node(btrn);
467 }
468
469 static void fecdec_open(struct filter_node *fn)
470 {
471 struct private_fecdec_data *pfd;
472 pfd = para_calloc(sizeof(*pfd));
473 fn->private_data = pfd;
474 fn->min_iqs = FEC_HEADER_SIZE;
475 }
476
477 /**
478 * The init function of the fecdec filter.
479 *
480 * \param f Struct to initialize.
481 */
482 void fecdec_filter_init(struct filter *f)
483 {
484 f->close = fecdec_close;
485 f->open = fecdec_open;
486 f->pre_select = generic_filter_pre_select;
487 f->post_select = fecdec_post_select;
488 }