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 }