src/pcm/pcm_alaw.c

   1 /*
   2  *  PCM - A-Law conversion
   3  *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
   4  *
   5  *
   6  *   This library is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU Library General Public License as
   8  *   published by the Free Software Foundation; either version 2 of
   9  *   the License, or (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU Library General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU Library General Public
  17  *   License along with this library; if not, write to the Free Software
  18  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  *
  20  */
  21
  22 #include <byteswap.h>
  23 #include "pcm_local.h"
  24 #include "pcm_plugin.h"
  25
  26 typedef void (*alaw_f)(const snd_pcm_channel_area_t *src_areas,
  27                         snd_pcm_uframes_t src_offset,
  28                         const snd_pcm_channel_area_t *dst_areas,
  29                         snd_pcm_uframes_t dst_offset,
  30                         unsigned int channels, snd_pcm_uframes_t frames, int getputidx);
  31
  32 typedef struct {
  33         /* This field need to be the first */
  34         snd_pcm_plugin_t plug;
  35         int getput_idx;
  36         alaw_f func;
  37         int sformat;
  38 } snd_pcm_alaw_t;
  39
  40 static inline int val_seg(int val)
  41 {
  42         int r = 1;
  43         val >>= 8;
  44         if (val & 0xf0) {
  45                 val >>= 4;
  46                 r += 4;
  47         }
  48         if (val & 0x0c) {
  49                 val >>= 2;
  50                 r += 2;
  51         }
  52         if (val & 0x02)
  53                 r += 1;
  54         return r;
  55 }
  56
  57 /*
  58  * s16_to_alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
  59  *
  60  * s16_to_alaw() accepts an 16-bit integer and encodes it as A-law data.
  61  *
  62  *              Linear Input Code       Compressed Code
  63  *      ------------------------        ---------------
  64  *      0000000wxyza                    000wxyz
  65  *      0000001wxyza                    001wxyz
  66  *      000001wxyzab                    010wxyz
  67  *      00001wxyzabc                    011wxyz
  68  *      0001wxyzabcd                    100wxyz
  69  *      001wxyzabcde                    101wxyz
  70  *      01wxyzabcdef                    110wxyz
  71  *      1wxyzabcdefg                    111wxyz
  72  *
  73  * For further information see John C. Bellamy's Digital Telephony, 1982,
  74  * John Wiley & Sons, pps 98-111 and 472-476.
  75  */
  76
  77 static unsigned char s16_to_alaw(int pcm_val)
  78 {
  79         int             mask;
  80         int             seg;
  81         unsigned char   aval;
  82
  83         if (pcm_val >= 0) {
  84                 mask = 0xD5;
  85         } else {
  86                 mask = 0x55;
  87                 pcm_val = -pcm_val;
  88                 if (pcm_val > 0x7fff)
  89                         pcm_val = 0x7fff;
  90         }
  91
  92         if (pcm_val < 256)
  93                 aval = pcm_val >> 4;
  94         else {
  95                 /* Convert the scaled magnitude to segment number. */
  96                 seg = val_seg(pcm_val);
  97                 aval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0x0f);
  98         }
  99         return aval ^ mask;
 100 }
 101
 102 /*
 103  * alaw_to_s16() - Convert an A-law value to 16-bit linear PCM
 104  *
 105  */
 106 static int alaw_to_s16(unsigned char a_val)
 107 {
 108         int             t;
 109         int             seg;
 110
 111         a_val ^= 0x55;
 112         t = a_val & 0x7f;
 113         if (t < 16)
 114                 t = (t << 4) + 8;
 115         else {
 116                 seg = (t >> 4) & 0x07;
 117                 t = ((t & 0x0f) << 4) + 0x108;
 118                 t <<= seg -1;
 119         }
 120         return ((a_val & 0x80) ? t : -t);
 121 }
 122
 123 static void alaw_decode(const snd_pcm_channel_area_t *src_areas,
 124                         snd_pcm_uframes_t src_offset,
 125                         const snd_pcm_channel_area_t *dst_areas,
 126                         snd_pcm_uframes_t dst_offset,
 127                         unsigned int channels, snd_pcm_uframes_t frames, int putidx)
 128 {
 129 #define PUT16_LABELS
 130 #include "plugin_ops.h"
 131 #undef PUT16_LABELS
 132         void *put = put16_labels[putidx];
 133         unsigned int channel;
 134         for (channel = 0; channel < channels; ++channel) {
 135                 char *src;
 136                 char *dst;
 137                 int src_step, dst_step;
 138                 snd_pcm_uframes_t frames1;
 139                 const snd_pcm_channel_area_t *src_area = &src_areas[channel];
 140                 const snd_pcm_channel_area_t *dst_area = &dst_areas[channel];
 141 #if 0
 142                 if (!src_area->enabled) {
 143                         if (dst_area->wanted)
 144                                 snd_pcm_area_silence(&dst_areas[channel], dst_offset, frames, dst_sfmt);
 145                         dst_area->enabled = 0;
 146                         continue;
 147                 }
 148                 dst_area->enabled = 1;
 149 #endif
 150                 src = snd_pcm_channel_area_addr(src_area, src_offset);
 151                 dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
 152                 src_step = snd_pcm_channel_area_step(src_area);
 153                 dst_step = snd_pcm_channel_area_step(dst_area);
 154                 frames1 = frames;
 155                 while (frames1-- > 0) {
 156                         int16_t sample = alaw_to_s16(*src);
 157                         goto *put;
 158 #define PUT16_END after
 159 #include "plugin_ops.h"
 160 #undef PUT16_END
 161                 after:
 162                         src += src_step;
 163                         dst += dst_step;
 164                 }
 165         }
 166 }
 167
 168 static void alaw_encode(const snd_pcm_channel_area_t *src_areas,
 169                          snd_pcm_uframes_t src_offset,
 170                          const snd_pcm_channel_area_t *dst_areas,
 171                          snd_pcm_uframes_t dst_offset,
 172                          unsigned int channels, snd_pcm_uframes_t frames, int getidx)
 173 {
 174 #define GET16_LABELS
 175 #include "plugin_ops.h"
 176 #undef GET16_LABELS
 177         void *get = get16_labels[getidx];
 178         unsigned int channel;
 179         int16_t sample = 0;
 180         for (channel = 0; channel < channels; ++channel) {
 181                 char *src;
 182                 char *dst;
 183                 int src_step, dst_step;
 184                 snd_pcm_uframes_t frames1;
 185                 const snd_pcm_channel_area_t *src_area = &src_areas[channel];
 186                 const snd_pcm_channel_area_t *dst_area = &dst_areas[channel];
 187 #if 0
 188                 if (!src_area->enabled) {
 189                         if (dst_area->wanted)
 190                                 snd_pcm_area_silence(&dst_area->area, 0, frames, dst_sfmt);
 191                         dst_area->enabled = 0;
 192                         continue;
 193                 }
 194                 dst_area->enabled = 1;
 195 #endif
 196                 src = snd_pcm_channel_area_addr(src_area, src_offset);
 197                 dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
 198                 src_step = snd_pcm_channel_area_step(src_area);
 199                 dst_step = snd_pcm_channel_area_step(dst_area);
 200                 frames1 = frames;
 201                 while (frames1-- > 0) {
 202                         goto *get;
 203 #define GET16_END after
 204 #include "plugin_ops.h"
 205 #undef GET16_END
 206                 after:
 207                         *dst = s16_to_alaw(sample);
 208                         src += src_step;
 209                         dst += dst_step;
 210                 }
 211         }
 212 }
 213
 214 static int snd_pcm_alaw_hw_refine_cprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
 215 {
 216         snd_pcm_alaw_t *alaw = pcm->private;
 217         int err;
 218         mask_t *access_mask = alloca(mask_sizeof());
 219         mask_load(access_mask, SND_PCM_ACCBIT_PLUGIN);
 220         err = _snd_pcm_hw_param_mask(params, SND_PCM_HW_PARAM_ACCESS,
 221                                      access_mask);
 222         if (err < 0)
 223                 return err;
 224         if (alaw->sformat == SND_PCM_FORMAT_A_LAW) {
 225                 mask_t *format_mask = alloca(mask_sizeof());
 226                 mask_load(format_mask, SND_PCM_FMTBIT_LINEAR);
 227                 err = _snd_pcm_hw_param_mask(params, SND_PCM_HW_PARAM_FORMAT,
 228                                              format_mask);
 229         } else {
 230                 err = _snd_pcm_hw_param_set(params,
 231                                             SND_PCM_HW_PARAM_FORMAT,
 232                                             SND_PCM_FORMAT_A_LAW, 0);
 233         }
 234         if (err < 0)
 235                 return err;
 236         err = _snd_pcm_hw_param_set(params, SND_PCM_HW_PARAM_SUBFORMAT,
 237                                      SND_PCM_SUBFORMAT_STD, 0);
 238         if (err < 0)
 239                 return err;
 240         params->info &= ~(SND_PCM_INFO_MMAP | SND_PCM_INFO_MMAP_VALID);
 241         return 0;
 242 }
 243
 244 static int snd_pcm_alaw_hw_refine_sprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *sparams)
 245 {
 246         snd_pcm_alaw_t *alaw = pcm->private;
 247         mask_t *saccess_mask = alloca(mask_sizeof());
 248         mask_load(saccess_mask, SND_PCM_ACCBIT_MMAP);
 249         _snd_pcm_hw_params_any(sparams);
 250         _snd_pcm_hw_param_mask(sparams, SND_PCM_HW_PARAM_ACCESS,
 251                                 saccess_mask);
 252         _snd_pcm_hw_param_set(sparams, SND_PCM_HW_PARAM_FORMAT,
 253                               alaw->sformat, 0);
 254         _snd_pcm_hw_param_set(sparams, SND_PCM_HW_PARAM_SUBFORMAT,
 255                               SND_PCM_SUBFORMAT_STD, 0);
 256         return 0;
 257 }
 258
 259 static int snd_pcm_alaw_hw_refine_schange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,
 260                                             snd_pcm_hw_params_t *sparams)
 261 {
 262         int err;
 263         unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS |
 264                               SND_PCM_HW_PARBIT_RATE |
 265                               SND_PCM_HW_PARBIT_PERIOD_SIZE |
 266                               SND_PCM_HW_PARBIT_BUFFER_SIZE |
 267                               SND_PCM_HW_PARBIT_PERIODS |
 268                               SND_PCM_HW_PARBIT_PERIOD_TIME |
 269                               SND_PCM_HW_PARBIT_BUFFER_TIME |
 270                               SND_PCM_HW_PARBIT_TICK_TIME);
 271         err = _snd_pcm_hw_params_refine(sparams, links, params);
 272         if (err < 0)
 273                 return err;
 274         return 0;
 275 }
 276
 277 static int snd_pcm_alaw_hw_refine_cchange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,
 278                                             snd_pcm_hw_params_t *sparams)
 279 {
 280         int err;
 281         unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS |
 282                               SND_PCM_HW_PARBIT_RATE |
 283                               SND_PCM_HW_PARBIT_PERIOD_SIZE |
 284                               SND_PCM_HW_PARBIT_BUFFER_SIZE |
 285                               SND_PCM_HW_PARBIT_PERIODS |
 286                               SND_PCM_HW_PARBIT_PERIOD_TIME |
 287                               SND_PCM_HW_PARBIT_BUFFER_TIME |
 288                               SND_PCM_HW_PARBIT_TICK_TIME);
 289         err = _snd_pcm_hw_params_refine(params, links, sparams);
 290         if (err < 0)
 291                 return err;
 292         return 0;
 293 }
 294
 295 static int snd_pcm_alaw_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
 296 {
 297         return snd_pcm_hw_refine_slave(pcm, params,
 298                                        snd_pcm_alaw_hw_refine_cprepare,
 299                                        snd_pcm_alaw_hw_refine_cchange,
 300                                        snd_pcm_alaw_hw_refine_sprepare,
 301                                        snd_pcm_alaw_hw_refine_schange,
 302                                        snd_pcm_plugin_hw_refine_slave);
 303 }
 304
 305 static int snd_pcm_alaw_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params)
 306 {
 307         snd_pcm_alaw_t *alaw = pcm->private;
 308         int err = snd_pcm_hw_params_slave(pcm, params,
 309                                           snd_pcm_alaw_hw_refine_cchange,
 310                                           snd_pcm_alaw_hw_refine_sprepare,
 311                                           snd_pcm_alaw_hw_refine_schange,
 312                                           snd_pcm_plugin_hw_params_slave);
 313         if (err < 0)
 314                 return err;
 315
 316         if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
 317                 if (alaw->sformat == SND_PCM_FORMAT_A_LAW) {
 318                         alaw->getput_idx = get_index(snd_pcm_hw_param_value(params, SND_PCM_HW_PARAM_FORMAT, 0), SND_PCM_FORMAT_S16);
 319                         alaw->func = alaw_encode;
 320                 } else {
 321                         alaw->getput_idx = put_index(SND_PCM_FORMAT_S16, alaw->sformat);
 322                         alaw->func = alaw_decode;
 323                 }
 324         } else {
 325                 if (alaw->sformat == SND_PCM_FORMAT_A_LAW) {
 326                         alaw->getput_idx = put_index(SND_PCM_FORMAT_S16, snd_pcm_hw_param_value(params, SND_PCM_HW_PARAM_FORMAT, 0));
 327                         alaw->func = alaw_decode;
 328                 } else {
 329                         alaw->getput_idx = get_index(alaw->sformat, SND_PCM_FORMAT_S16);
 330                         alaw->func = alaw_encode;
 331                 }
 332         }
 333         return 0;
 334 }
 335
 336 static snd_pcm_sframes_t snd_pcm_alaw_write_areas(snd_pcm_t *pcm,
 337                                         const snd_pcm_channel_area_t *areas,
 338                                         snd_pcm_uframes_t offset,
 339                                         snd_pcm_uframes_t size,
 340                                         snd_pcm_uframes_t *slave_sizep)
 341 {
 342         snd_pcm_alaw_t *alaw = pcm->private;
 343         snd_pcm_t *slave = alaw->plug.slave;
 344         snd_pcm_uframes_t xfer = 0;
 345         snd_pcm_sframes_t err = 0;
 346         if (slave_sizep && *slave_sizep < size)
 347                 size = *slave_sizep;
 348         assert(size > 0);
 349         while (xfer < size) {
 350                 snd_pcm_uframes_t frames = snd_pcm_mmap_playback_xfer(slave, size - xfer);
 351                 alaw->func(areas, offset,
 352                             snd_pcm_mmap_areas(slave), snd_pcm_mmap_offset(slave),
 353                             pcm->channels, frames,
 354                             alaw->getput_idx);
 355                 err = snd_pcm_mmap_forward(slave, frames);
 356                 if (err < 0)
 357                         break;
 358                 assert((snd_pcm_uframes_t)err == frames);
 359                 offset += err;
 360                 xfer += err;
 361                 snd_pcm_mmap_hw_forward(pcm, err);
 362         }
 363         if (xfer > 0) {
 364                 if (slave_sizep)
 365                         *slave_sizep = xfer;
 366                 return xfer;
 367         }
 368         return err;
 369 }
 370
 371 static snd_pcm_sframes_t snd_pcm_alaw_read_areas(snd_pcm_t *pcm,
 372                                        const snd_pcm_channel_area_t *areas,
 373                                        snd_pcm_uframes_t offset,
 374                                        snd_pcm_uframes_t size,
 375                                        snd_pcm_uframes_t *slave_sizep)
 376 {
 377         snd_pcm_alaw_t *alaw = pcm->private;
 378         snd_pcm_t *slave = alaw->plug.slave;
 379         snd_pcm_uframes_t xfer = 0;
 380         snd_pcm_sframes_t err = 0;
 381         if (slave_sizep && *slave_sizep < size)
 382                 size = *slave_sizep;
 383         assert(size > 0);
 384         while (xfer < size) {
 385                 snd_pcm_uframes_t frames = snd_pcm_mmap_capture_xfer(slave, size - xfer);
 386                 alaw->func(snd_pcm_mmap_areas(slave), snd_pcm_mmap_offset(slave),
 387                            areas, offset,
 388                            pcm->channels, frames,
 389                            alaw->getput_idx);
 390                 err = snd_pcm_mmap_forward(slave, frames);
 391                 if (err < 0)
 392                         break;
 393                 assert((snd_pcm_uframes_t)err == frames);
 394                 offset += err;
 395                 xfer += err;
 396                 snd_pcm_mmap_hw_forward(pcm, err);
 397         }
 398         if (xfer > 0) {
 399                 if (slave_sizep)
 400                         *slave_sizep = xfer;
 401                 return xfer;
 402         }
 403         return err;
 404 }
 405
 406 static void snd_pcm_alaw_dump(snd_pcm_t *pcm, snd_output_t *out)
 407 {
 408         snd_pcm_alaw_t *alaw = pcm->private;
 409         snd_output_printf(out, "A-Law conversion PCM (%s)\n",
 410                 snd_pcm_format_name(alaw->sformat));
 411         if (pcm->setup) {
 412                 snd_output_printf(out, "Its setup is:\n");
 413                 snd_pcm_dump_setup(pcm, out);
 414         }
 415         snd_output_printf(out, "Slave: ");
 416         snd_pcm_dump(alaw->plug.slave, out);
 417 }
 418
 419 snd_pcm_ops_t snd_pcm_alaw_ops = {
 420         close: snd_pcm_plugin_close,
 421         card: snd_pcm_plugin_card,
 422         info: snd_pcm_plugin_info,
 423         hw_refine: snd_pcm_alaw_hw_refine,
 424         hw_params: snd_pcm_alaw_hw_params,
 425         hw_free: snd_pcm_plugin_hw_free,
 426         sw_params: snd_pcm_plugin_sw_params,
 427         channel_info: snd_pcm_plugin_channel_info,
 428         dump: snd_pcm_alaw_dump,
 429         nonblock: snd_pcm_plugin_nonblock,
 430         async: snd_pcm_plugin_async,
 431         mmap: snd_pcm_plugin_mmap,
 432         munmap: snd_pcm_plugin_munmap,
 433 };
 434
 435 int snd_pcm_alaw_open(snd_pcm_t **pcmp, char *name, int sformat, snd_pcm_t *slave, int close_slave)
 436 {
 437         snd_pcm_t *pcm;
 438         snd_pcm_alaw_t *alaw;
 439         assert(pcmp && slave);
 440         if (snd_pcm_format_linear(sformat) != 1 &&
 441             sformat != SND_PCM_FORMAT_A_LAW)
 442                 return -EINVAL;
 443         alaw = calloc(1, sizeof(snd_pcm_alaw_t));
 444         if (!alaw) {
 445                 return -ENOMEM;
 446         }
 447         alaw->sformat = sformat;
 448         alaw->plug.read = snd_pcm_alaw_read_areas;
 449         alaw->plug.write = snd_pcm_alaw_write_areas;
 450         alaw->plug.slave = slave;
 451         alaw->plug.close_slave = close_slave;
 452
 453         pcm = calloc(1, sizeof(snd_pcm_t));
 454         if (!pcm) {
 455                 free(alaw);
 456                 return -ENOMEM;
 457         }
 458         if (name)
 459                 pcm->name = strdup(name);
 460         pcm->type = SND_PCM_TYPE_ALAW;
 461         pcm->stream = slave->stream;
 462         pcm->mode = slave->mode;
 463         pcm->ops = &snd_pcm_alaw_ops;
 464         pcm->op_arg = pcm;
 465         pcm->fast_ops = &snd_pcm_plugin_fast_ops;
 466         pcm->fast_op_arg = pcm;
 467         pcm->private = alaw;
 468         pcm->poll_fd = slave->poll_fd;
 469         pcm->hw_ptr = &alaw->plug.hw_ptr;
 470         pcm->appl_ptr = &alaw->plug.appl_ptr;
 471         *pcmp = pcm;
 472
 473         return 0;
 474 }
 475
 476 int _snd_pcm_alaw_open(snd_pcm_t **pcmp, char *name,
 477                          snd_config_t *conf,
 478                          int stream, int mode)
 479 {
 480         snd_config_iterator_t i;
 481         char *sname = NULL;
 482         int err;
 483         snd_pcm_t *spcm;
 484         int sformat = -1;
 485         snd_config_foreach(i, conf) {
 486                 snd_config_t *n = snd_config_entry(i);
 487                 if (strcmp(n->id, "comment") == 0)
 488                         continue;
 489                 if (strcmp(n->id, "type") == 0)
 490                         continue;
 491                 if (strcmp(n->id, "stream") == 0)
 492                         continue;
 493                 if (strcmp(n->id, "sname") == 0) {
 494                         err = snd_config_string_get(n, &sname);
 495                         if (err < 0) {
 496                                 ERR("Invalid type for %s", n->id);
 497                                 return -EINVAL;
 498                         }
 499                         continue;
 500                 }
 501                 if (strcmp(n->id, "sformat") == 0) {
 502                         char *f;
 503                         err = snd_config_string_get(n, &f);
 504                         if (err < 0) {
 505                                 ERR("Invalid type for %s", n->id);
 506                                 return -EINVAL;
 507                         }
 508                         sformat = snd_pcm_format_value(f);
 509                         if (sformat < 0) {
 510                                 ERR("Unknown sformat");
 511                                 return -EINVAL;
 512                         }
 513                         if (snd_pcm_format_linear(sformat) != 1 &&
 514                             sformat != SND_PCM_FORMAT_A_LAW) {
 515                                 ERR("Invalid sformat");
 516                                 return -EINVAL;
 517                         }
 518                         continue;
 519                 }
 520                 ERR("Unknown field %s", n->id);
 521                 return -EINVAL;
 522         }
 523         if (!sname) {
 524                 ERR("sname is not defined");
 525                 return -EINVAL;
 526         }
 527         if (sformat < 0) {
 528                 ERR("sformat is not defined");
 529                 return -EINVAL;
 530         }
 531         /* This is needed cause snd_config_update may destroy config */
 532         sname = strdup(sname);
 533         if (!sname)
 534                 return  -ENOMEM;
 535         err = snd_pcm_open(&spcm, sname, stream, mode);
 536         free(sname);
 537         if (err < 0)
 538                 return err;
 539         err = snd_pcm_alaw_open(pcmp, name, sformat, spcm, 1);
 540         if (err < 0)
 541                 snd_pcm_close(spcm);
 542         return err;
 543 }
 544
 545