fecdec.c: Add some more sanity checks to find_group().
[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 (128 * 1024)
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 static int group_complete(struct fecdec_group *fg)
82 {
83 return fg->num_received_slices >= fg->h.data_slices_per_group;
84 }
85
86 static int group_empty(struct fecdec_group *fg)
87 {
88 return fg->num_received_slices == 0;
89 }
90
91 static void clear_group(struct fecdec_group *fg)
92 {
93 int i;
94
95 for (i = 0; i < fg->num_slices; i++) {
96 free(fg->data[i]);
97 fg->data[i] = NULL;
98 fg->idx[i] = -1;
99 }
100 free(fg->data);
101 free(fg->idx);
102 fg->num_slices = 0;
103 memset(&fg->h, 0, sizeof(struct fec_header));
104 fg->num_received_slices = 0;
105 }
106
107 static int find_group(struct fec_header *h,
108 struct private_fecdec_data *pfd, struct fecdec_group **result)
109 {
110 struct fecdec_group *fg;
111
112 FOR_EACH_FECDEC_GROUP(fg, pfd) {
113 if (fg->h.group_num != h->group_num)
114 continue;
115 if (fg->h.slices_per_group != h->slices_per_group)
116 continue;
117 if (fg->h.data_slices_per_group != h->data_slices_per_group)
118 continue;
119 *result = fg;
120 return 1;
121 }
122 return 0;
123 }
124
125 static struct fecdec_group *find_unused_group(struct private_fecdec_data *pfd)
126 {
127 struct fecdec_group *fg;
128
129 FOR_EACH_FECDEC_GROUP(fg, pfd) {
130 if (fg->num_received_slices == 0)
131 return fg;
132 }
133 return NULL;
134 }
135
136 static struct fecdec_group *try_to_free_group(struct private_fecdec_data *pfd)
137 {
138 struct fecdec_group *fg;
139
140 FOR_EACH_FECDEC_GROUP(fg, pfd) {
141 if (!group_complete(fg))
142 continue;
143 clear_group(fg);
144 return fg;
145 }
146 return NULL;
147 }
148
149 static struct fecdec_group *free_oldest_group(struct private_fecdec_data *pfd)
150 {
151 struct fecdec_group *fg, *oldest = NULL;
152
153 FOR_EACH_FECDEC_GROUP(fg, pfd) {
154 if (!oldest || oldest->h.group_num > fg->h.group_num)
155 oldest = fg;
156 }
157 if (!group_complete(oldest) && !group_empty(oldest))
158 PARA_WARNING_LOG("Clearing incomplete group %d "
159 "(contains %d slices)\n", fg->h.group_num,
160 fg->num_received_slices);
161 clear_group(oldest);
162 return oldest;
163 }
164
165 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
166 struct fecdec_group **result)
167 {
168 struct fecdec_group *fg;
169 int ret = find_group(h, pfd, &fg);
170
171 if (ret < 0)
172 return ret;
173 if (ret > 0) /* found group */
174 goto success;
175 /* group not found */
176 fg = find_unused_group(pfd);
177 if (fg)
178 goto update_header;
179 fg = try_to_free_group(pfd);
180 if (fg)
181 goto update_header;
182 fg = free_oldest_group(pfd);
183 update_header:
184 fg->h = *h;
185 success:
186 *result = fg;
187 return 1;
188 }
189
190 static int add_slice(char *buf, struct fecdec_group *fg)
191 {
192 int r, slice_num;
193
194 if (group_complete(fg))
195 return 0;
196 slice_num = fg->h.slice_num;
197 if (fg->num_slices == 0) {
198 fg->num_slices = fg->h.slices_per_group;
199 fg->idx = malloc(fg->num_slices * sizeof(int));
200 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
201 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
202 }
203 r = fg->num_received_slices;
204 fg->idx[r] = slice_num;
205 fg->data[r] = malloc(fg->h.slice_bytes);
206 memcpy(fg->data[r], buf, fg->h.slice_bytes);
207 fg->num_received_slices++;
208 return 1;
209 }
210
211 static int decode_group(struct fecdec_group *fg, struct filter_node *fn)
212 {
213 int i, ret, sb = fg->h.slice_bytes;
214 size_t written = 0;
215 struct private_fecdec_data *pfd = fn->private_data;
216
217 ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
218 if (ret < 0)
219 return ret;
220 PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
221 fg->h.group_num, fg->h.group_bytes,
222 fg->h.data_slices_per_group * sb);
223 for (i = 0; i < fg->h.data_slices_per_group; i++) {
224 size_t n = sb;
225 if (n + written > fg->h.group_bytes)
226 n = fg->h.group_bytes - written;
227 if (fn->loaded + n > fn->bufsize)
228 return -E_FECDEC_OVERRUN;
229 memcpy(fn->buf + fn->loaded, fg->data[i], n);
230 fn->loaded += n;
231 written += n;
232 }
233 return 0;
234 }
235
236 /**
237 * Read a fec header from a buffer.
238 *
239 * \param buf The buffer to write to.
240 * \param h The fec header to write.
241 */
242 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
243 {
244 uint32_t magic;
245
246 if (len < FEC_HEADER_SIZE)
247 return 0;
248 magic = read_u32(buf);
249 if (magic != FEC_MAGIC)
250 return -E_BAD_FEC_HEADER;
251 h->slices_per_group = read_u8(buf + 4);
252 h->data_slices_per_group = read_u8(buf + 5);
253 h->audio_header_size = read_u32(buf + 6);
254
255 h->group_num = read_u32(buf + 10);
256 h->group_bytes = read_u32(buf + 14);
257
258 h->slice_num = read_u8(buf + 18);
259 h->slice_bytes = read_u16(buf + 20);
260 if (!h->group_bytes && & h->slice_bytes)
261 return -E_FECDEC_EOF;
262 // PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
263 // h->group_num, h->slice_num, h->slices_per_group);
264 return 1;
265 }
266
267 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
268 struct filter_node *fn)
269 {
270 struct fecdec_group *fg;
271 int ret;
272 struct private_fecdec_data *pfd = fn->private_data;
273
274 if (h->slice_bytes > len) /* can not use the thing, try to read more */
275 return 0;
276 ret = get_group(h, pfd, &fg);
277 if (ret < 0)
278 return ret;
279 if (group_complete(fg)) {
280 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
281 h->slice_num);
282 return 1;
283 }
284 fg->h = *h;
285 ret = add_slice(buf, fg);
286 if (ret < 0)
287 return ret;
288 if (group_complete(fg)) {
289 if (!pfd->fec) {
290 int k = h->data_slices_per_group, n = h->slices_per_group;
291 PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
292 ret = fec_new(k, n, &pfd->fec);
293 if (ret < 0)
294 return ret;
295 }
296 ret = decode_group(fg, fn);
297 if (ret < 0)
298 return ret;
299 }
300 return 1;
301 }
302
303 static int fecdec(char *buf, size_t len, struct filter_node *fn)
304 {
305 int ret;
306 struct fec_header h;
307
308 ret = read_fec_header(buf, len, &h);
309 if (ret <= 0)
310 return ret;
311 if (h.slice_bytes > fn->bufsize)
312 return -E_BAD_SLICE_SIZE;
313 if (h.slice_num > h.slices_per_group)
314 return -E_BAD_SLICE_NUM;
315 ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
316 &h, fn);
317 //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
318 if (ret <= 0)
319 return ret;
320 return FEC_HEADER_SIZE + h.slice_bytes;
321 }
322
323 static void fecdec_close(struct filter_node *fn)
324 {
325 struct private_fecdec_data *pfd = fn->private_data;
326 struct fecdec_group *fg;
327
328 FOR_EACH_FECDEC_GROUP(fg, pfd)
329 clear_group(fg);
330 free(fn->buf);
331 fn->buf = NULL;
332 free(fn->private_data);
333 fn->private_data = NULL;
334 }
335
336 static void fecdec_open(struct filter_node *fn)
337 {
338 fn->bufsize = FECDEC_OUTBUF_SIZE;
339 fn->buf = para_malloc(fn->bufsize);
340 fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
341 fn->loaded = 0;
342 }
343
344 /**
345 * The init function of the fecdec filter.
346 *
347 * \param f struct to initialize.
348 */
349 void fecdec_filter_init(struct filter *f)
350 {
351 f->convert = fecdec;
352 f->close = fecdec_close;
353 f->open = fecdec_open;
354 }