Remove an overambitious sanity check in the fecdec filter.
[paraslash.git] / fecdec_filter.c
1 /*
2 * Copyright (C) 2009 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 fec-decodes an audio stream. */
8
9 #include <dirent.h>
10 #include "para.h"
11 #include "error.h"
12 #include "list.h"
13 #include "sched.h"
14 #include "ggo.h"
15 #include "filter.h"
16 #include "string.h"
17 #include "portable_io.h"
18 #include "fec.h"
19 #include "fd.h"
20
21 /**
22 * How many FEC groups to store in memory.
23 *
24 * Packet reordering requires to keep more than one FEC group in memory because
25 * slices belonging to the next FEC group may arrive before the current FEC group
26 * is complete.
27 */
28 #define NUM_FEC_GROUPS 3
29
30 /** Size of the output buffer of the fecdec filter. */
31 #define FECDEC_OUTBUF_SIZE (1024 * 1024) /* FIXME: This has to depend on the fec params */
32
33 /** Data read from the header of a slice. */
34 struct fec_header {
35 /** Total number of slices in this group. */
36 uint8_t slices_per_group;
37 /** Number of slices needed to start decoding. */
38 uint8_t data_slices_per_group;
39 /** Size of the ogg vorbis header (zero for mp3, aac). */
40 uint32_t audio_header_size;
41 /** Number of the FEC group this slice belongs to. */
42 uint32_t group_num;
43 /** Size of the data in this FEC group. */
44 uint32_t group_bytes;
45 /** Number of this slice in the group. */
46 uint8_t slice_num;
47 /** Used data bytes of this slice. */
48 uint16_t slice_bytes;
49 /** Non-zero if this group is the beginning of the stream. */
50 uint8_t bos;
51 /** Non-zero if this stream embedds audio headers into fec groups. */
52 uint8_t header_stream;
53 };
54
55 /**
56 * The status of one partially received FEC group.
57 */
58 struct fecdec_group {
59 /** The header read from the last slice. */
60 struct fec_header h;
61 /** How many slices received so far. */
62 int num_received_slices;
63 /** The size of the \a idx and the \a data arrays below. */
64 int num_slices;
65 /** Array of indices of the received slices. */
66 int *idx;
67 /** Content of the received slices. */
68 unsigned char **data;
69 };
70
71 /**
72 * Data private to the fecdec filter.
73 */
74 struct private_fecdec_data {
75 /** Used by the fec core code. */
76 struct fec_parms *fec;
77 /** Keeps track of what was received so far. */
78 struct fecdec_group groups[NUM_FEC_GROUPS];
79 int have_header;
80 };
81
82 /** Iterate over all fecdec groups. */
83 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
84 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
85
86 static int group_complete(struct fecdec_group *fg)
87 {
88 return fg->num_received_slices >= fg->h.data_slices_per_group;
89 }
90
91 static int group_empty(struct fecdec_group *fg)
92 {
93 return fg->num_received_slices == 0;
94 }
95
96 static void clear_group(struct fecdec_group *fg)
97 {
98 int i;
99
100 for (i = 0; i < fg->num_slices; i++) {
101 free(fg->data[i]);
102 fg->data[i] = NULL;
103 fg->idx[i] = -1;
104 }
105 free(fg->data);
106 free(fg->idx);
107 fg->num_slices = 0;
108 memset(&fg->h, 0, sizeof(struct fec_header));
109 fg->num_received_slices = 0;
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 clear_group(fg);
154 return fg;
155 }
156 return NULL;
157 }
158
159 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
160 {
161 struct fecdec_group *fg, *oldest = NULL;
162
163 FOR_EACH_FECDEC_GROUP(fg, pfd) {
164 if (!oldest || oldest->h.group_num > fg->h.group_num)
165 oldest = fg;
166 }
167 if (!group_complete(oldest) && !group_empty(oldest))
168 PARA_WARNING_LOG("Clearing incomplete group %d "
169 "(contains %d slices)\n", oldest->h.group_num,
170 oldest->num_received_slices);
171 clear_group(oldest);
172 return oldest;
173 }
174
175 /* returns 1 if the group was found, 0 if not, negative on errors */
176 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
177 struct fecdec_group **result)
178 {
179 struct fecdec_group *fg;
180 int ret = find_group(h, pfd, &fg);
181
182 if (ret < 0)
183 return ret;
184 if (ret > 0) /* found group */
185 goto success;
186 /* group not found */
187 fg = find_unused_group(pfd);
188 if (fg)
189 goto success;
190 fg = try_to_free_group(pfd);
191 if (fg)
192 goto success;
193 fg = free_oldest_group(pfd);
194 ret = 0;
195 success:
196 fg->h = *h;
197 *result = fg;
198 return ret;
199 }
200
201 /*
202 * returns 1 if slice was added, zero otherwise (because the group was already
203 * complete). In any case the number of received slices is being increased by
204 * one.
205 */
206 static int add_slice(char *buf, struct fecdec_group *fg)
207 {
208 int r, slice_num;
209
210 if (group_complete(fg)) {
211 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
212 fg->h.slice_num);
213 fg->num_received_slices++;
214 return 0;
215 }
216 slice_num = fg->h.slice_num;
217 if (fg->num_slices == 0) {
218 fg->num_slices = fg->h.slices_per_group;
219 fg->idx = malloc(fg->num_slices * sizeof(int));
220 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
221 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
222 }
223 r = fg->num_received_slices;
224 fg->idx[r] = slice_num;
225 fg->data[r] = malloc(fg->h.slice_bytes);
226 memcpy(fg->data[r], buf, fg->h.slice_bytes);
227 fg->num_received_slices++;
228 return 1;
229 }
230
231 enum fec_group_usability {
232 FEC_GROUP_UNUSABLE,
233 FEC_GROUP_USABLE,
234 FEC_GROUP_USABLE_SKIP_HEADER,
235 };
236
237 static enum fec_group_usability group_is_usable(struct fecdec_group *fg,
238 struct private_fecdec_data *pfd)
239 {
240 struct fec_header *h = &fg->h;
241
242 if (!h->header_stream)
243 return FEC_GROUP_USABLE;
244 if (pfd->have_header) {
245 if (h->audio_header_size)
246 return FEC_GROUP_USABLE_SKIP_HEADER;
247 return FEC_GROUP_USABLE;
248 }
249 if (fg->h.bos)
250 return FEC_GROUP_USABLE;
251 if (fg->h.audio_header_size)
252 return FEC_GROUP_USABLE;
253 return FEC_GROUP_UNUSABLE;
254 }
255
256 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
257 {
258 int i, ret, sb = fg->h.slice_bytes;
259 size_t written = 0;
260 struct private_fecdec_data *pfd = fn->private_data;
261 enum fec_group_usability u = group_is_usable(fg, pfd);
262
263 if (u == FEC_GROUP_UNUSABLE) {
264 PARA_INFO_LOG("dropping unusable group %d\n", fg->h.group_num);
265 return 0;
266 }
267 PARA_DEBUG_LOG("decoding group %d %d slices\n", fg->h.group_num,
268 fg->h.data_slices_per_group);
269 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
270 if (ret < 0)
271 return ret;
272 pfd->have_header = 1;
273 i = 0;
274 if (u == FEC_GROUP_USABLE_SKIP_HEADER) {
275 i = ROUND_UP(fg->h.audio_header_size, fg->h.slice_bytes)
276 / fg->h.slice_bytes;
277 PARA_DEBUG_LOG("skipping %d header slices\n", i);
278 }
279 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
280 fg->h.group_num, fg->h.group_bytes,
281 fg->h.data_slices_per_group * sb);
282 for (; i < fg->h.data_slices_per_group; i++) {
283 size_t n = sb;
284 if (n + written > fg->h.group_bytes)
285 n = fg->h.group_bytes - written;
286 if (fn->loaded + n > fn->bufsize)
287 return -E_FECDEC_OVERRUN;
288 memcpy(fn->buf + fn->loaded, fg->data[i], n);
289 fn->loaded += n;
290 written += n;
291 }
292 return 0;
293 }
294
295 /**
296 * Read a fec header from a buffer.
297 *
298 * \param buf The buffer to write to.
299 * \param h The fec header to write.
300 */
301 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
302 {
303 uint32_t magic;
304
305 if (len < FEC_HEADER_SIZE)
306 return 0;
307 magic = read_u32(buf);
308 if (magic != FEC_MAGIC)
309 return -E_BAD_FEC_HEADER;
310 h->slices_per_group = read_u8(buf + 4);
311 h->data_slices_per_group = read_u8(buf + 5);
312 h->audio_header_size = read_u32(buf + 6);
313
314 h->group_num = read_u32(buf + 10);
315 h->group_bytes = read_u32(buf + 14);
316
317 h->slice_num = read_u8(buf + 18);
318 h->slice_bytes = read_u16(buf + 20);
319 h->bos = read_u8(buf + 22);
320 h->header_stream = read_u8(buf + 23);
321 if (!memcmp(buf, FEC_EOF_PACKET, FEC_EOF_PACKET_LEN))
322 return -E_FECDEC_EOF;
323 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
324 // h->group_num, h->slice_num, h->slices_per_group);
325 return 1;
326 }
327
328 /* returns 1 if we used the buffer, 0 if we didn't, negative on errors */
329 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
330 struct filter_node *fn)
331 {
332 struct fecdec_group *fg;
333 int ret;
334 struct private_fecdec_data *pfd = fn->private_data;
335
336 if (h->slice_bytes > len) /* can not use the thing, try to read more */
337 return 0;
338 ret = get_group(h, pfd, &fg);
339 if (ret < 0)
340 return ret;
341 if (!add_slice(buf, fg))
342 return 1;
343 if (group_complete(fg)) {
344 if (!pfd->fec) {
345 int k = h->data_slices_per_group, n = h->slices_per_group;
346 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
347 ret = fec_new(k, n, &pfd->fec);
348 if (ret < 0)
349 return ret;
350 }
351 ret = decode_group(fg, fn);
352 if (ret < 0)
353 return ret;
354 }
355 return 1;
356 }
357
358 static ssize_t fecdec(char *buf, size_t len, struct filter_node *fn)
359 {
360 int ret;
361 struct fec_header h;
362
363 ret = read_fec_header(buf, len, &h);
364 if (ret <= 0)
365 return ret;
366 if (!h.slice_bytes)
367 return -E_BAD_SLICE_SIZE;
368 if (h.slice_num > h.slices_per_group)
369 return -E_BAD_SLICE_NUM;
370 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
371 &h, fn);
372 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
373 if (ret <= 0)
374 return ret;
375 return FEC_HEADER_SIZE + h.slice_bytes;
376 }
377
378 static void fecdec_close(struct filter_node *fn)
379 {
380 struct private_fecdec_data *pfd = fn->private_data;
381 struct fecdec_group *fg;
382
383 FOR_EACH_FECDEC_GROUP(fg, pfd)
384 clear_group(fg);
385 free(fn->buf);
386 fn->buf = NULL;
387 fec_free(pfd->fec);
388 free(fn->private_data);
389 fn->private_data = NULL;
390 }
391
392 static void fecdec_open(struct filter_node *fn)
393 {
394 fn->bufsize = FECDEC_OUTBUF_SIZE;
395 fn->buf = para_malloc(fn->bufsize);
396 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
397 fn->loaded = 0;
398 }
399
400 /**
401 * The init function of the fecdec filter.
402 *
403 * \param f struct to initialize.
404 */
405 void fecdec_filter_init(struct filter *f)
406 {
407 f->convert = fecdec;
408 f->close = fecdec_close;
409 f->open = fecdec_open;
410 }