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 fecdev_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 #define NUM_FEC_GROUPS 3
  22 #define INPUT_BUFFER_SIZE 16384
  23
  24 /** size of the output buffer */
  25 #define FECDEC_OUTBUF_SIZE 81920
  26
  27 struct fec_header {
  28         uint8_t slices_per_group;
  29         uint8_t data_slices_per_group;
  30         uint32_t audio_header_size;
  31
  32         uint32_t group_num;
  33         uint32_t group_bytes;
  34
  35         uint8_t slice_num;
  36         uint16_t slice_bytes;
  37 };
  38
  39 struct fec_group {
  40         struct fec_header h;
  41         int num_received_slices;
  42         int num_slices;
  43         int *idx;
  44         unsigned char **data;
  45 };
  46
  47 struct private_fecdec_data {
  48         struct fec_parms *fec;
  49         struct fec_group groups[NUM_FEC_GROUPS];
  50 };
  51
  52 #define FOR_EACH_FEC_GROUP(g, d) for (g = (d)->groups; \
  53         (g) - (d)->groups < NUM_FEC_GROUPS; (g)++)
  54
  55 #define UNUSED_GROUP_NUM 0xffffffff
  56
  57 static int group_complete(struct fec_group *fg)
  58 {
  59         if (fg->h.group_num == UNUSED_GROUP_NUM)
  60                 return 0;
  61         //PARA_INFO_LOG("received slices: %u, slices per group: %u\n", fg->num_received_slices, fg->h.data_slices_per_group);
  62         return fg->num_received_slices >= fg->h.data_slices_per_group;
  63 }
  64
  65 static int group_empty(struct fec_group *fg)
  66 {
  67         return fg->num_received_slices == 0;
  68 }
  69
  70 static void clear_group(struct fec_group *fg)
  71 {
  72         int i;
  73
  74         if (!group_complete(fg) && !group_empty(fg))
  75                 PARA_WARNING_LOG("Clearing incomplete group %d "
  76                         "(contains %d slices)\n", fg->h.group_num,
  77                         fg->num_received_slices);
  78         for (i = 0; i < fg->num_slices; i++) {
  79                 free(fg->data[i]);
  80                 fg->data[i] = NULL;
  81                 fg->idx[i] = -1;
  82         }
  83         free(fg->data);
  84         free(fg->idx);
  85         fg->num_slices = 0;
  86         memset(&fg->h, 0, sizeof(struct fec_header));
  87         fg->num_received_slices = 0;
  88         fg->h.group_num = UNUSED_GROUP_NUM;
  89 }
  90
  91 static int find_group(struct fec_header *h,
  92                 struct private_fecdec_data *pfd, struct fec_group **result)
  93 {
  94         struct fec_group *fg;
  95
  96         FOR_EACH_FEC_GROUP(fg, pfd) {
  97                 if (fg->h.group_num != h->group_num)
  98                         continue;
  99                 *result = fg;
 100                 return 1;
 101         }
 102         return 0;
 103 }
 104
 105 static struct fec_group *find_unused_group(struct private_fecdec_data *pfd)
 106 {
 107         struct fec_group *fg;
 108
 109         FOR_EACH_FEC_GROUP(fg, pfd) {
 110                 if (fg->num_received_slices == 0)
 111                         return fg;
 112         }
 113         return NULL;
 114 }
 115
 116 static struct fec_group *try_to_free_group(struct private_fecdec_data *pfd)
 117 {
 118         struct fec_group *fg;
 119
 120         FOR_EACH_FEC_GROUP(fg, pfd) {
 121                 if (!group_complete(fg))
 122                         continue;
 123                 clear_group(fg);
 124                 return fg;
 125         }
 126         return NULL;
 127 }
 128
 129 static struct fec_group *free_oldest_group(struct private_fecdec_data *pfd)
 130 {
 131         struct fec_group *fg, *oldest = NULL;
 132
 133         FOR_EACH_FEC_GROUP(fg, pfd) {
 134                 if (!oldest || oldest->h.group_num > fg->h.group_num)
 135                         oldest = fg;
 136         }
 137         clear_group(oldest);
 138         return oldest;
 139 }
 140
 141 static int get_group(struct fec_header *h, struct private_fecdec_data *pfd,
 142                 struct fec_group **result)
 143 {
 144         struct fec_group *fg;
 145         int ret = find_group(h, pfd, &fg);
 146
 147         if (ret < 0)
 148                 return ret;
 149         if (ret > 0) /* found group */
 150                 goto success;
 151         /* group not found */
 152         fg = find_unused_group(pfd);
 153         if (fg)
 154                 goto update_header;
 155         fg = try_to_free_group(pfd);
 156         if (fg)
 157                 goto update_header;
 158         fg = free_oldest_group(pfd);
 159 update_header:
 160         fg->h = *h;
 161 success:
 162         *result = fg;
 163         return 1;
 164 }
 165
 166 static int add_slice(char *buf, struct fec_group *fg)
 167 {
 168         int r, slice_num;
 169
 170         if (group_complete(fg))
 171                 return 0;
 172         slice_num = fg->h.slice_num;
 173         if (fg->num_slices == 0) {
 174                 fg->num_slices = fg->h.slices_per_group;
 175                 fg->idx = malloc(fg->num_slices * sizeof(int));
 176                 fg->data = malloc(fg->num_slices * sizeof(unsigned char *));
 177                 memset(fg->data, 0, fg->num_slices * sizeof(unsigned char *));
 178         }
 179         r = fg->num_received_slices;
 180         fg->idx[r] = slice_num;
 181         fg->data[r] = malloc(fg->h.slice_bytes);
 182         memcpy(fg->data[r], buf, fg->h.slice_bytes);
 183         fg->num_received_slices++;
 184         return 1;
 185 }
 186
 187 static int decode_group(struct fec_group *fg, struct filter_node *fn)
 188 {
 189         int i, ret, sb = fg->h.slice_bytes;
 190         size_t written = 0;
 191         struct private_fecdec_data *pfd = fn->private_data;
 192
 193         ret = fec_decode(pfd->fec, fg->data, fg->idx, sb);
 194         if (ret < 0)
 195                 return ret;
 196         PARA_DEBUG_LOG("writing group %d (%d/%d decoded data bytes)\n",
 197                 fg->h.group_num, fg->h.group_bytes,
 198                 fg->h.data_slices_per_group * sb);
 199         for (i = 0; i < fg->h.data_slices_per_group; i++) {
 200                 size_t n = sb;
 201                 if (n + written > fg->h.group_bytes)
 202                         n = fg->h.group_bytes - written;
 203                 if (fn->loaded + n > fn->bufsize)
 204                         return -E_FECDEC_OVERRUN;
 205                 memcpy(fn->buf + fn->loaded, fg->data[i], n);
 206                 fn->loaded += n;
 207                 written += n;
 208         }
 209         return 0;
 210 }
 211
 212 /**
 213  * Read a fec header from a buffer.
 214  *
 215  * \param buf The buffer to write to.
 216  * \param h The fec header to write.
 217  */
 218 static int read_fec_header(char *buf, size_t len, struct fec_header *h)
 219 {
 220         uint32_t magic;
 221
 222         if (len < FEC_HEADER_SIZE)
 223                 return 0;
 224         magic = read_u32(buf);
 225         if (magic != FEC_MAGIC)
 226                 return -E_BAD_FEC_HEADER;
 227         h->slices_per_group = read_u8(buf + 4);
 228         h->data_slices_per_group = read_u8(buf + 5);
 229         h->audio_header_size = read_u32(buf + 6);
 230
 231         h->group_num = read_u32(buf + 10);
 232         h->group_bytes = read_u32(buf + 14);
 233
 234         h->slice_num = read_u8(buf + 18);
 235         h->slice_bytes = read_u16(buf + 20);
 236         if (!h->group_bytes && & h->slice_bytes)
 237                 return -E_FECDEC_EOF;
 238 //      PARA_DEBUG_LOG("group %u, slize %u, slices per group: %u\n",
 239 //              h->group_num, h->slice_num, h->slices_per_group);
 240         return 1;
 241 }
 242
 243 static int dispatch_slice(char *buf, size_t len, struct fec_header *h,
 244                 struct filter_node *fn)
 245 {
 246         struct fec_group *fg;
 247         int ret;
 248         struct private_fecdec_data *pfd = fn->private_data;
 249
 250         if (h->slice_bytes > len) /* can not use the thing, try to read more */
 251                 return 0;
 252         ret = get_group(h, pfd, &fg);
 253         if (ret < 0)
 254                 return ret;
 255         if (group_complete(fg)) {
 256                 PARA_DEBUG_LOG("group complete, ignoring slice %d\n",
 257                         h->slice_num);
 258                 return 1;
 259         }
 260         fg->h = *h;
 261         ret = add_slice(buf, fg);
 262         if (ret < 0)
 263                 return ret;
 264         if (group_complete(fg)) {
 265                 if (!pfd->fec) {
 266                         int k = h->data_slices_per_group, n = h->slices_per_group;
 267                         PARA_NOTICE_LOG("init fec (%d, %d)\n", k, n);
 268                         ret = fec_new(k, n, &pfd->fec);
 269                         if (ret < 0)
 270                                 return ret;
 271                 }
 272                 ret = decode_group(fg, fn);
 273                 if (ret < 0)
 274                         return ret;
 275         }
 276         return 1;
 277 }
 278
 279 static int fecdec(char *buf, size_t len, struct filter_node *fn)
 280 {
 281         int ret;
 282         struct fec_header h;
 283
 284         ret = read_fec_header(buf, len, &h);
 285         if (ret <= 0)
 286                 return ret;
 287         if (h.slice_bytes > INPUT_BUFFER_SIZE)
 288                 return -E_BAD_SLICE_SIZE;
 289         if (h.slice_num > h.slices_per_group)
 290                 return -E_BAD_SLICE_NUM;
 291         ret = dispatch_slice(buf + FEC_HEADER_SIZE, len - FEC_HEADER_SIZE,
 292                 &h, fn);
 293         //PARA_INFO_LOG("ret: %d, len: %d, slice_bytes: %d\n", ret, len, h.slice_bytes);
 294         if (ret <= 0)
 295                 return ret;
 296         return FEC_HEADER_SIZE + h.slice_bytes;
 297 }
 298
 299 static void fecdec_close(struct filter_node *fn)
 300 {
 301         struct private_fecdec_data *pfd = fn->private_data;
 302         struct fec_group *fg;
 303
 304         FOR_EACH_FEC_GROUP(fg, pfd)
 305                 clear_group(fg);
 306         free(fn->buf);
 307         fn->buf = NULL;
 308         free(fn->private_data);
 309         fn->private_data = NULL;
 310 }
 311
 312 static void fecdec_open(struct filter_node *fn)
 313 {
 314         fn->bufsize = FECDEC_OUTBUF_SIZE;
 315         fn->buf = para_malloc(fn->bufsize);
 316         fn->private_data = para_calloc(sizeof(struct private_fecdec_data));
 317         fn->loaded = 0;
 318 }
 319
 320 /**
 321  * The init function of the fecdec filter.
 322  *
 323  * \param f struct to initialize.
 324  */
 325 void fecdec_filter_init(struct filter *f)
 326 {
 327         f->convert = fecdec;
 328         f->close = fecdec_close;
 329         f->open = fecdec_open;
 330 }