fecdec_filter cleanups and documentation improvements.
[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 81920
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 };
50
51 /**
52 * The status of one partially received FEC group.
53 */
54 struct fecdec_group {
55 /** The header read from the last slice. */
56 struct fec_header h;
57 /** How many slices received so far. */
58 int num_received_slices;
59 /** The size of the \a idx and the \a data arrays below. */
60 int num_slices;
61 /** Array of indices of the received slices. */
62 int *idx;
63 /** Content of the received slices. */
64 unsigned char **data;
65 };
66
67 /**
68 * Data private to the fecdec filter.
69 */
70 struct private_fecdec_data {
71 /** Used by the fec core code. */
72 struct fec_parms *fec;
73 /** Keeps track of what was received so far. */
74 struct fecdec_group groups[NUM_FEC_GROUPS];
75 };
76
77 /** Iterate over all fecdec groups. */
78 #define FOR_EACH_FECDEC_GROUP(g, d) for (g = (d)->groups; \
79 (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
80
81 /** */
82 #define UNUSED_GROUP_NUM 0xffffffff
83
84 static int group_complete(struct fecdec_group *fg)
85 {
86 if (fg->h.group_num == UNUSED_GROUP_NUM)
87 return 0;
88 //PARA_INFO_LOG("received slices: %u, slices per group: %u\n", fg->num_received_slices, fg->h.data_slices_per_group);
89 return fg->num_received_slices >= fg->h.data_slices_per_group;
90 }
91
92 static int group_empty(struct fecdec_group *fg)
93 {
94 return fg->num_received_slices == 0;
95 }
96
97 static void clear_group(struct fecdec_group *fg)
98 {
99 int i;
100
101 if (!group_complete(fg) && !group_empty(fg))
102 PARA_WARNING_LOG("Clearing incomplete group %d "
103 "(contains %d slices)\n", fg->h.group_num,
104 fg->num_received_slices);
105 for (i = 0; i < fg->num_slices; i++) {
106 free(fg->data[i]);
107 fg->data[i] = NULL;
108 fg->idx[i] = -1;
109 }
110 free(fg->data);
111 free(fg->idx);
112 fg->num_slices = 0;
113 memset(&fg->h, 0, sizeof(struct fec_header));
114 fg->num_received_slices = 0;
115 fg->h.group_num = UNUSED_GROUP_NUM;
116 }
117
118 static int find_group(struct fec_header *h,
119 struct private_fecdec_data *pfd, struct fecdec_group **result)
120 {
121 struct fecdec_group *fg;
122
123 FOR_EACH_FECDEC_GROUP(fg, pfd) {
124 if (fg->h.group_num != h->group_num)
125 continue;
126 /* FIXME: Add some more sanity checks here */
127 *result = fg;
128 return 1;
129 }
130 return 0;
131 }
132
133 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
134 {
135 struct fecdec_group *fg;
136
137 FOR_EACH_FECDEC_GROUP(fg, pfd) {
138 if (fg->num_received_slices == 0)
139 return fg;
140 }
141 return NULL;
142 }
143
144 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
145 {
146 struct fecdec_group *fg;
147
148 FOR_EACH_FECDEC_GROUP(fg, pfd) {
149 if (!group_complete(fg))
150 continue;
151 clear_group(fg);
152 return fg;
153 }
154 return NULL;
155 }
156
157 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
158 {
159 struct fecdec_group *fg, *oldest = NULL;
160
161 FOR_EACH_FECDEC_GROUP(fg, pfd) {
162 if (!oldest || oldest->h.group_num > fg->h.group_num)
163 oldest = fg;
164 }
165 clear_group(oldest);
166 return oldest;
167 }
168
169 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
170 struct fecdec_group **result)
171 {
172 struct fecdec_group *fg;
173 int ret = find_group(h, pfd, &fg);
174
175 if (ret < 0)
176 return ret;
177 if (ret > 0) /* found group */
178 goto success;
179 /* group not found */
180 fg = find_unused_group(pfd);
181 if (fg)
182 goto update_header;
183 fg = try_to_free_group(pfd);
184 if (fg)
185 goto update_header;
186 fg = free_oldest_group(pfd);
187 update_header:
188 fg->h = *h;
189 success:
190 *result = fg;
191 return 1;
192 }
193
194 static int add_slice(char *buf, struct fecdec_group *fg)
195 {
196 int r, slice_num;
197
198 if (group_complete(fg))
199 return 0;
200 slice_num = fg->h.slice_num;
201 if (fg->num_slices == 0) {
202 fg->num_slices = fg->h.slices_per_group;
203 fg->idx = malloc(fg->num_slices * sizeof(int));
204 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
205 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
206 }
207 r = fg->num_received_slices;
208 fg->idx[r] = slice_num;
209 fg->data[r] = malloc(fg->h.slice_bytes);
210 memcpy(fg->data[r], buf, fg->h.slice_bytes);
211 fg->num_received_slices++;
212 return 1;
213 }
214
215 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
216 {
217 int i, ret, sb = fg->h.slice_bytes;
218 size_t written = 0;
219 struct private_fecdec_data *pfd = fn->private_data;
220
221 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
222 if (ret < 0)
223 return ret;
224 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
225 fg->h.group_num, fg->h.group_bytes,
226 fg->h.data_slices_per_group * sb);
227 for (i = 0; i < fg->h.data_slices_per_group; i++) {
228 size_t n = sb;
229 if (n + written > fg->h.group_bytes)
230 n = fg->h.group_bytes - written;
231 if (fn->loaded + n > fn->bufsize)
232 return -E_FECDEC_OVERRUN;
233 memcpy(fn->buf + fn->loaded, fg->data[i], n);
234 fn->loaded += n;
235 written += n;
236 }
237 return 0;
238 }
239
240 /**
241 * Read a fec header from a buffer.
242 *
243 * \param buf The buffer to write to.
244 * \param h The fec header to write.
245 */
246 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
247 {
248 uint32_t magic;
249
250 if (len < FEC_HEADER_SIZE)
251 return 0;
252 magic = read_u32(buf);
253 if (magic != FEC_MAGIC)
254 return -E_BAD_FEC_HEADER;
255 h->slices_per_group = read_u8(buf + 4);
256 h->data_slices_per_group = read_u8(buf + 5);
257 h->audio_header_size = read_u32(buf + 6);
258
259 h->group_num = read_u32(buf + 10);
260 h->group_bytes = read_u32(buf + 14);
261
262 h->slice_num = read_u8(buf + 18);
263 h->slice_bytes = read_u16(buf + 20);
264 if (!h->group_bytes && & h->slice_bytes)
265 return -E_FECDEC_EOF;
266 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
267 // h->group_num, h->slice_num, h->slices_per_group);
268 return 1;
269 }
270
271 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
272 struct filter_node *fn)
273 {
274 struct fecdec_group *fg;
275 int ret;
276 struct private_fecdec_data *pfd = fn->private_data;
277
278 if (h->slice_bytes > len) /* can not use the thing, try to read more */
279 return 0;
280 ret = get_group(h, pfd, &fg);
281 if (ret < 0)
282 return ret;
283 if (group_complete(fg)) {
284 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
285 h->slice_num);
286 return 1;
287 }
288 fg->h = *h;
289 ret = add_slice(buf, fg);
290 if (ret < 0)
291 return ret;
292 if (group_complete(fg)) {
293 if (!pfd->fec) {
294 int k = h->data_slices_per_group, n = h->slices_per_group;
295 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
296 ret = fec_new(k, n, &pfd->fec);
297 if (ret < 0)
298 return ret;
299 }
300 ret = decode_group(fg, fn);
301 if (ret < 0)
302 return ret;
303 }
304 return 1;
305 }
306
307 static int fecdec(char *buf, size_t len, struct filter_node *fn)
308 {
309 int ret;
310 struct fec_header h;
311
312 ret = read_fec_header(buf, len, &h);
313 if (ret <= 0)
314 return ret;
315 if (h.slice_bytes > fn->bufsize)
316 return -E_BAD_SLICE_SIZE;
317 if (h.slice_num > h.slices_per_group)
318 return -E_BAD_SLICE_NUM;
319 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
320 &h, fn);
321 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
322 if (ret <= 0)
323 return ret;
324 return FEC_HEADER_SIZE + h.slice_bytes;
325 }
326
327 static void fecdec_close(struct filter_node *fn)
328 {
329 struct private_fecdec_data *pfd = fn->private_data;
330 struct fecdec_group *fg;
331
332 FOR_EACH_FECDEC_GROUP(fg, pfd)
333 clear_group(fg);
334 free(fn->buf);
335 fn->buf = NULL;
336 free(fn->private_data);
337 fn->private_data = NULL;
338 }
339
340 static void fecdec_open(struct filter_node *fn)
341 {
342 fn->bufsize = FECDEC_OUTBUF_SIZE;
343 fn->buf = para_malloc(fn->bufsize);
344 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
345 fn->loaded = 0;
346 }
347
348 /**
349 * The init function of the fecdec filter.
350 *
351 * \param f struct to initialize.
352 */
353 void fecdec_filter_init(struct filter *f)
354 {
355 f->convert = fecdec;
356 f->close = fecdec_close;
357 f->open = fecdec_open;
358 }