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