sound/core/pcm_misc.c

   1 /*
   2  *  PCM Interface - misc routines
   3  *  Copyright (c) 1998 by Jaroslav Kysela <perex@suse.cz>
   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <sound/driver.h>
  23 #include <linux/time.h>
  24 #include <sound/core.h>
  25 #include <sound/pcm.h>
  26 #define bswap_16 swab16
  27 #define bswap_32 swab32
  28 #define bswap_64 swab64
  29 #define SND_PCM_FORMAT_UNKNOWN (-1)
  30 #define snd_enum_to_int(v) (v)
  31 #define snd_int_to_enum(v) (v)
  32
  33 /**
  34  * snd_pcm_format_signed - Check the PCM format is signed linear
  35  * @format: the format to check
  36  *
  37  * Returns 1 if the given PCM format is signed linear, 0 if unsigned
  38  * linear, and a negative error code for non-linear formats.
  39  */
  40 int snd_pcm_format_signed(snd_pcm_format_t format)
  41 {
  42         switch (snd_enum_to_int(format)) {
  43         case SNDRV_PCM_FORMAT_S8:
  44         case SNDRV_PCM_FORMAT_S16_LE:
  45         case SNDRV_PCM_FORMAT_S16_BE:
  46         case SNDRV_PCM_FORMAT_S24_LE:
  47         case SNDRV_PCM_FORMAT_S24_BE:
  48         case SNDRV_PCM_FORMAT_S32_LE:
  49         case SNDRV_PCM_FORMAT_S32_BE:
  50         case SNDRV_PCM_FORMAT_S24_3LE:
  51         case SNDRV_PCM_FORMAT_S24_3BE:
  52         case SNDRV_PCM_FORMAT_S20_3LE:
  53         case SNDRV_PCM_FORMAT_S20_3BE:
  54         case SNDRV_PCM_FORMAT_S18_3LE:
  55         case SNDRV_PCM_FORMAT_S18_3BE:
  56                 return 1;
  57         case SNDRV_PCM_FORMAT_U8:
  58         case SNDRV_PCM_FORMAT_U16_LE:
  59         case SNDRV_PCM_FORMAT_U16_BE:
  60         case SNDRV_PCM_FORMAT_U24_LE:
  61         case SNDRV_PCM_FORMAT_U24_BE:
  62         case SNDRV_PCM_FORMAT_U32_LE:
  63         case SNDRV_PCM_FORMAT_U32_BE:
  64         case SNDRV_PCM_FORMAT_U24_3LE:
  65         case SNDRV_PCM_FORMAT_U24_3BE:
  66         case SNDRV_PCM_FORMAT_U20_3LE:
  67         case SNDRV_PCM_FORMAT_U20_3BE:
  68         case SNDRV_PCM_FORMAT_U18_3LE:
  69         case SNDRV_PCM_FORMAT_U18_3BE:
  70                 return 0;
  71         default:
  72                 return -EINVAL;
  73         }
  74 }
  75
  76 /**
  77  * snd_pcm_format_unsigned - Check the PCM format is unsigned linear
  78  * @format: the format to check
  79  *
  80  * Returns 1 if the given PCM format is unsigned linear, 0 if signed
  81  * linear, and a negative error code for non-linear formats.
  82  */
  83 int snd_pcm_format_unsigned(snd_pcm_format_t format)
  84 {
  85         int val;
  86
  87         val = snd_pcm_format_signed(format);
  88         if (val < 0)
  89                 return val;
  90         return !val;
  91 }
  92
  93 /**
  94  * snd_pcm_format_linear - Check the PCM format is linear
  95  * @format: the format to check
  96  *
  97  * Returns 1 if the given PCM format is linear, 0 if not.
  98  */
  99 int snd_pcm_format_linear(snd_pcm_format_t format)
 100 {
 101         return snd_pcm_format_signed(format) >= 0;
 102 }
 103
 104 /**
 105  * snd_pcm_format_little_endian - Check the PCM format is little-endian
 106  * @format: the format to check
 107  *
 108  * Returns 1 if the given PCM format is little-endian, 0 if
 109  * big-endian, or a negative error code if endian not specified.
 110  */
 111 int snd_pcm_format_little_endian(snd_pcm_format_t format)
 112 {
 113         switch (snd_enum_to_int(format)) {
 114         case SNDRV_PCM_FORMAT_S16_LE:
 115         case SNDRV_PCM_FORMAT_U16_LE:
 116         case SNDRV_PCM_FORMAT_S24_LE:
 117         case SNDRV_PCM_FORMAT_U24_LE:
 118         case SNDRV_PCM_FORMAT_S32_LE:
 119         case SNDRV_PCM_FORMAT_U32_LE:
 120         case SNDRV_PCM_FORMAT_FLOAT_LE:
 121         case SNDRV_PCM_FORMAT_FLOAT64_LE:
 122         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE:
 123         case SNDRV_PCM_FORMAT_S24_3LE:
 124         case SNDRV_PCM_FORMAT_S20_3LE:
 125         case SNDRV_PCM_FORMAT_S18_3LE:
 126         case SNDRV_PCM_FORMAT_U24_3LE:
 127         case SNDRV_PCM_FORMAT_U20_3LE:
 128         case SNDRV_PCM_FORMAT_U18_3LE:
 129                 return 1;
 130         case SNDRV_PCM_FORMAT_S16_BE:
 131         case SNDRV_PCM_FORMAT_U16_BE:
 132         case SNDRV_PCM_FORMAT_S24_BE:
 133         case SNDRV_PCM_FORMAT_U24_BE:
 134         case SNDRV_PCM_FORMAT_S32_BE:
 135         case SNDRV_PCM_FORMAT_U32_BE:
 136         case SNDRV_PCM_FORMAT_FLOAT_BE:
 137         case SNDRV_PCM_FORMAT_FLOAT64_BE:
 138         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE:
 139         case SNDRV_PCM_FORMAT_S24_3BE:
 140         case SNDRV_PCM_FORMAT_S20_3BE:
 141         case SNDRV_PCM_FORMAT_S18_3BE:
 142         case SNDRV_PCM_FORMAT_U24_3BE:
 143         case SNDRV_PCM_FORMAT_U20_3BE:
 144         case SNDRV_PCM_FORMAT_U18_3BE:
 145                 return 0;
 146         default:
 147                 return -EINVAL;
 148         }
 149 }
 150
 151 /**
 152  * snd_pcm_format_big_endian - Check the PCM format is big-endian
 153  * @format: the format to check
 154  *
 155  * Returns 1 if the given PCM format is big-endian, 0 if
 156  * little-endian, or a negative error code if endian not specified.
 157  */
 158 int snd_pcm_format_big_endian(snd_pcm_format_t format)
 159 {
 160         int val;
 161
 162         val = snd_pcm_format_little_endian(format);
 163         if (val < 0)
 164                 return val;
 165         return !val;
 166 }
 167
 168 /**
 169  * snd_pcm_format_cpu_endian - Check the PCM format is CPU-endian
 170  * @format: the format to check
 171  *
 172  * Returns 1 if the given PCM format is CPU-endian, 0 if
 173  * opposite, or a negative error code if endian not specified.
 174  */
 175 int snd_pcm_format_cpu_endian(snd_pcm_format_t format)
 176 {
 177 #ifdef SNDRV_LITTLE_ENDIAN
 178         return snd_pcm_format_little_endian(format);
 179 #else
 180         return snd_pcm_format_big_endian(format);
 181 #endif
 182 }
 183
 184 /**
 185  * snd_pcm_format_width - return the bit-width of the format
 186  * @format: the format to check
 187  *
 188  * Returns the bit-width of the format, or a negative error code
 189  * if unknown format.
 190  */
 191 int snd_pcm_format_width(snd_pcm_format_t format)
 192 {
 193         switch (snd_enum_to_int(format)) {
 194         case SNDRV_PCM_FORMAT_S8:
 195         case SNDRV_PCM_FORMAT_U8:
 196                 return 8;
 197         case SNDRV_PCM_FORMAT_S16_LE:
 198         case SNDRV_PCM_FORMAT_S16_BE:
 199         case SNDRV_PCM_FORMAT_U16_LE:
 200         case SNDRV_PCM_FORMAT_U16_BE:
 201                 return 16;
 202         case SNDRV_PCM_FORMAT_S18_3LE:
 203         case SNDRV_PCM_FORMAT_S18_3BE:
 204         case SNDRV_PCM_FORMAT_U18_3LE:
 205         case SNDRV_PCM_FORMAT_U18_3BE:
 206                 return 18;
 207         case SNDRV_PCM_FORMAT_S20_3LE:
 208         case SNDRV_PCM_FORMAT_S20_3BE:
 209         case SNDRV_PCM_FORMAT_U20_3LE:
 210         case SNDRV_PCM_FORMAT_U20_3BE:
 211                 return 20;
 212         case SNDRV_PCM_FORMAT_S24_LE:
 213         case SNDRV_PCM_FORMAT_S24_BE:
 214         case SNDRV_PCM_FORMAT_U24_LE:
 215         case SNDRV_PCM_FORMAT_U24_BE:
 216         case SNDRV_PCM_FORMAT_S24_3LE:
 217         case SNDRV_PCM_FORMAT_S24_3BE:
 218         case SNDRV_PCM_FORMAT_U24_3LE:
 219         case SNDRV_PCM_FORMAT_U24_3BE:
 220                 return 24;
 221         case SNDRV_PCM_FORMAT_S32_LE:
 222         case SNDRV_PCM_FORMAT_S32_BE:
 223         case SNDRV_PCM_FORMAT_U32_LE:
 224         case SNDRV_PCM_FORMAT_U32_BE:
 225         case SNDRV_PCM_FORMAT_FLOAT_LE:
 226         case SNDRV_PCM_FORMAT_FLOAT_BE:
 227                 return 32;
 228         case SNDRV_PCM_FORMAT_FLOAT64_LE:
 229         case SNDRV_PCM_FORMAT_FLOAT64_BE:
 230                 return 64;
 231         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE:
 232         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE:
 233                 return 24;
 234         case SNDRV_PCM_FORMAT_MU_LAW:
 235         case SNDRV_PCM_FORMAT_A_LAW:
 236                 return 8;
 237         case SNDRV_PCM_FORMAT_IMA_ADPCM:
 238                 return 4;
 239         default:
 240                 return -EINVAL;
 241         }
 242 }
 243
 244 /**
 245  * snd_pcm_format_physical_width - return the physical bit-width of the format
 246  * @format: the format to check
 247  *
 248  * Returns the physical bit-width of the format, or a negative error code
 249  * if unknown format.
 250  */
 251 int snd_pcm_format_physical_width(snd_pcm_format_t format)
 252 {
 253         switch (snd_enum_to_int(format)) {
 254         case SNDRV_PCM_FORMAT_S8:
 255         case SNDRV_PCM_FORMAT_U8:
 256                 return 8;
 257         case SNDRV_PCM_FORMAT_S16_LE:
 258         case SNDRV_PCM_FORMAT_S16_BE:
 259         case SNDRV_PCM_FORMAT_U16_LE:
 260         case SNDRV_PCM_FORMAT_U16_BE:
 261                 return 16;
 262         case SNDRV_PCM_FORMAT_S18_3LE:
 263         case SNDRV_PCM_FORMAT_S18_3BE:
 264         case SNDRV_PCM_FORMAT_U18_3LE:
 265         case SNDRV_PCM_FORMAT_U18_3BE:
 266         case SNDRV_PCM_FORMAT_S20_3LE:
 267         case SNDRV_PCM_FORMAT_S20_3BE:
 268         case SNDRV_PCM_FORMAT_U20_3LE:
 269         case SNDRV_PCM_FORMAT_U20_3BE:
 270         case SNDRV_PCM_FORMAT_S24_3LE:
 271         case SNDRV_PCM_FORMAT_S24_3BE:
 272         case SNDRV_PCM_FORMAT_U24_3LE:
 273         case SNDRV_PCM_FORMAT_U24_3BE:
 274                 return 24;
 275         case SNDRV_PCM_FORMAT_S24_LE:
 276         case SNDRV_PCM_FORMAT_S24_BE:
 277         case SNDRV_PCM_FORMAT_U24_LE:
 278         case SNDRV_PCM_FORMAT_U24_BE:
 279         case SNDRV_PCM_FORMAT_S32_LE:
 280         case SNDRV_PCM_FORMAT_S32_BE:
 281         case SNDRV_PCM_FORMAT_U32_LE:
 282         case SNDRV_PCM_FORMAT_U32_BE:
 283         case SNDRV_PCM_FORMAT_FLOAT_LE:
 284         case SNDRV_PCM_FORMAT_FLOAT_BE:
 285         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE:
 286         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE:
 287                 return 32;
 288         case SNDRV_PCM_FORMAT_FLOAT64_LE:
 289         case SNDRV_PCM_FORMAT_FLOAT64_BE:
 290                 return 64;
 291         case SNDRV_PCM_FORMAT_MU_LAW:
 292         case SNDRV_PCM_FORMAT_A_LAW:
 293                 return 8;
 294         case SNDRV_PCM_FORMAT_IMA_ADPCM:
 295                 return 4;
 296         default:
 297                 return -EINVAL;
 298         }
 299 }
 300
 301 /**
 302  * snd_pcm_format_size - return the byte size of samples on the given format
 303  * @format: the format to check
 304  *
 305  * Returns the byte size of the given samples for the format, or a
 306  * negative error code if unknown format.
 307  */
 308 ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples)
 309 {
 310         switch (snd_enum_to_int(format)) {
 311         case SNDRV_PCM_FORMAT_S8:
 312         case SNDRV_PCM_FORMAT_U8:
 313                 return samples;
 314         case SNDRV_PCM_FORMAT_S16_LE:
 315         case SNDRV_PCM_FORMAT_S16_BE:
 316         case SNDRV_PCM_FORMAT_U16_LE:
 317         case SNDRV_PCM_FORMAT_U16_BE:
 318                 return samples * 2;
 319         case SNDRV_PCM_FORMAT_S18_3LE:
 320         case SNDRV_PCM_FORMAT_S18_3BE:
 321         case SNDRV_PCM_FORMAT_U18_3LE:
 322         case SNDRV_PCM_FORMAT_U18_3BE:
 323         case SNDRV_PCM_FORMAT_S20_3LE:
 324         case SNDRV_PCM_FORMAT_S20_3BE:
 325         case SNDRV_PCM_FORMAT_U20_3LE:
 326         case SNDRV_PCM_FORMAT_U20_3BE:
 327         case SNDRV_PCM_FORMAT_S24_3LE:
 328         case SNDRV_PCM_FORMAT_S24_3BE:
 329         case SNDRV_PCM_FORMAT_U24_3LE:
 330         case SNDRV_PCM_FORMAT_U24_3BE:
 331                 return samples * 3;
 332         case SNDRV_PCM_FORMAT_S24_LE:
 333         case SNDRV_PCM_FORMAT_S24_BE:
 334         case SNDRV_PCM_FORMAT_U24_LE:
 335         case SNDRV_PCM_FORMAT_U24_BE:
 336         case SNDRV_PCM_FORMAT_S32_LE:
 337         case SNDRV_PCM_FORMAT_S32_BE:
 338         case SNDRV_PCM_FORMAT_U32_LE:
 339         case SNDRV_PCM_FORMAT_U32_BE:
 340         case SNDRV_PCM_FORMAT_FLOAT_LE:
 341         case SNDRV_PCM_FORMAT_FLOAT_BE:
 342                 return samples * 4;
 343         case SNDRV_PCM_FORMAT_FLOAT64_LE:
 344         case SNDRV_PCM_FORMAT_FLOAT64_BE:
 345                 return samples * 8;
 346         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE:
 347         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE:
 348                 return samples * 4;
 349         case SNDRV_PCM_FORMAT_MU_LAW:
 350         case SNDRV_PCM_FORMAT_A_LAW:
 351                 return samples;
 352         case SNDRV_PCM_FORMAT_IMA_ADPCM:
 353                 if (samples & 1)
 354                         return -EINVAL;
 355                 return samples / 2;
 356         default:
 357                 return -EINVAL;
 358         }
 359 }
 360
 361 /**
 362  * snd_pcm_format_silence_64 - return the silent data in 64bit integer
 363  * @format: the format to check
 364  *
 365  * Returns the silent data in 64bit integer for the given format.
 366  */
 367 u_int64_t snd_pcm_format_silence_64(snd_pcm_format_t format)
 368 {
 369         switch (snd_enum_to_int(format)) {
 370         case SNDRV_PCM_FORMAT_S8:
 371         case SNDRV_PCM_FORMAT_S16_LE:
 372         case SNDRV_PCM_FORMAT_S16_BE:
 373         case SNDRV_PCM_FORMAT_S24_LE:
 374         case SNDRV_PCM_FORMAT_S24_BE:
 375         case SNDRV_PCM_FORMAT_S32_LE:
 376         case SNDRV_PCM_FORMAT_S32_BE:
 377         case SNDRV_PCM_FORMAT_S24_3LE:
 378         case SNDRV_PCM_FORMAT_S24_3BE:
 379         case SNDRV_PCM_FORMAT_S20_3LE:
 380         case SNDRV_PCM_FORMAT_S20_3BE:
 381         case SNDRV_PCM_FORMAT_S18_3LE:
 382         case SNDRV_PCM_FORMAT_S18_3BE:
 383                 return 0;
 384         case SNDRV_PCM_FORMAT_U8:
 385                 return 0x8080808080808080ULL;
 386 #ifdef SNDRV_LITTLE_ENDIAN
 387         case SNDRV_PCM_FORMAT_U16_LE:
 388                 return 0x8000800080008000ULL;
 389         case SNDRV_PCM_FORMAT_U24_LE:
 390                 return 0x0080000000800000ULL;
 391         case SNDRV_PCM_FORMAT_U32_LE:
 392                 return 0x8000000080000000ULL;
 393         case SNDRV_PCM_FORMAT_U16_BE:
 394                 return 0x0080008000800080ULL;
 395         case SNDRV_PCM_FORMAT_U24_BE:
 396                 return 0x0000800000008000ULL;
 397         case SNDRV_PCM_FORMAT_U32_BE:
 398                 return 0x0000008000000080ULL;
 399         case SNDRV_PCM_FORMAT_U24_3LE:
 400                 return 0x0000800000800000ULL;
 401         case SNDRV_PCM_FORMAT_U24_3BE:
 402                 return 0x0080000080000080ULL;
 403         case SNDRV_PCM_FORMAT_U20_3LE:
 404                 return 0x0000080000080000ULL;
 405         case SNDRV_PCM_FORMAT_U20_3BE:
 406                 return 0x0008000008000008ULL;
 407         case SNDRV_PCM_FORMAT_U18_3LE:
 408                 return 0x0000020000020000ULL;
 409         case SNDRV_PCM_FORMAT_U18_3BE:
 410                 return 0x0002000002000002ULL;
 411 #else
 412         case SNDRV_PCM_FORMAT_U16_LE:
 413                 return 0x0080008000800080ULL;
 414         case SNDRV_PCM_FORMAT_U24_LE:
 415                 return 0x0000800000008000ULL;
 416         case SNDRV_PCM_FORMAT_U32_LE:
 417                 return 0x0000008000000080ULL;
 418         case SNDRV_PCM_FORMAT_U16_BE:
 419                 return 0x8000800080008000ULL;
 420         case SNDRV_PCM_FORMAT_U24_BE:
 421                 return 0x0080000000800000ULL;
 422         case SNDRV_PCM_FORMAT_U32_BE:
 423                 return 0x8000000080000000ULL;
 424         case SNDRV_PCM_FORMAT_U24_3LE:
 425                 return 0x0080000080000080ULL;
 426         case SNDRV_PCM_FORMAT_U24_3BE:
 427                 return 0x0000800000800000ULL;
 428         case SNDRV_PCM_FORMAT_U20_3LE:
 429                 return 0x0008000008000008ULL;
 430         case SNDRV_PCM_FORMAT_U20_3BE:
 431                 return 0x0000080000080000ULL;
 432         case SNDRV_PCM_FORMAT_U18_3LE:
 433                 return 0x0002000002000002ULL;
 434         case SNDRV_PCM_FORMAT_U18_3BE:
 435                 return 0x0000020000020000ULL;
 436 #endif
 437         case SNDRV_PCM_FORMAT_FLOAT_LE:
 438         {
 439                 union {
 440                         float f;
 441                         u_int32_t i;
 442                 } u;
 443                 u.f = 0.0;
 444 #ifdef SNDRV_LITTLE_ENDIAN
 445                 return u.i;
 446 #else
 447                 return bswap_32(u.i);
 448 #endif
 449         }
 450         case SNDRV_PCM_FORMAT_FLOAT64_LE:
 451         {
 452                 union {
 453                         double f;
 454                         u_int64_t i;
 455                 } u;
 456                 u.f = 0.0;
 457 #ifdef SNDRV_LITTLE_ENDIAN
 458                 return u.i;
 459 #else
 460                 return bswap_64(u.i);
 461 #endif
 462         }
 463         case SNDRV_PCM_FORMAT_FLOAT_BE:
 464         {
 465                 union {
 466                         float f;
 467                         u_int32_t i;
 468                 } u;
 469                 u.f = 0.0;
 470 #ifdef SNDRV_LITTLE_ENDIAN
 471                 return bswap_32(u.i);
 472 #else
 473                 return u.i;
 474 #endif
 475         }
 476         case SNDRV_PCM_FORMAT_FLOAT64_BE:
 477         {
 478                 union {
 479                         double f;
 480                         u_int64_t i;
 481                 } u;
 482                 u.f = 0.0;
 483 #ifdef SNDRV_LITTLE_ENDIAN
 484                 return bswap_64(u.i);
 485 #else
 486                 return u.i;
 487 #endif
 488         }
 489         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE:
 490         case SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE:
 491                 return 0;
 492         case SNDRV_PCM_FORMAT_MU_LAW:
 493                 return 0x7f7f7f7f7f7f7f7fULL;
 494         case SNDRV_PCM_FORMAT_A_LAW:
 495                 return 0x5555555555555555ULL;
 496         case SNDRV_PCM_FORMAT_IMA_ADPCM:        /* special case */
 497         case SNDRV_PCM_FORMAT_MPEG:
 498         case SNDRV_PCM_FORMAT_GSM:
 499         case SNDRV_PCM_FORMAT_SPECIAL:
 500                 return 0;
 501         default:
 502                 return -EINVAL;
 503         }
 504         return 0;
 505 }
 506
 507 u_int32_t snd_pcm_format_silence_32(snd_pcm_format_t format)
 508 {
 509         return (u_int32_t)snd_pcm_format_silence_64(format);
 510 }
 511
 512 u_int16_t snd_pcm_format_silence_16(snd_pcm_format_t format)
 513 {
 514         return (u_int16_t)snd_pcm_format_silence_64(format);
 515 }
 516
 517 u_int8_t snd_pcm_format_silence(snd_pcm_format_t format)
 518 {
 519         return (u_int8_t)snd_pcm_format_silence_64(format);
 520 }
 521
 522 /**
 523  * snd_pcm_format_set_silence - set the silence data on the buffer
 524  * @format: the PCM format
 525  * @data: the buffer pointer
 526  * @samples: the number of samples to set silence
 527  *
 528  * Sets the silence data on the buffer for the given samples.
 529  *
 530  * Returns zero if successful, or a negative error code on failure.
 531  */
 532 int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int samples)
 533 {
 534         if (samples == 0)
 535                 return 0;
 536         switch (snd_pcm_format_width(format)) {
 537         case 4: {
 538                 u_int8_t silence = snd_pcm_format_silence_64(format);
 539                 unsigned int samples1;
 540                 if (samples % 2 != 0)
 541                         return -EINVAL;
 542                 samples1 = samples / 2;
 543                 memset(data, silence, samples1);
 544                 break;
 545         }
 546         case 8: {
 547                 u_int8_t silence = snd_pcm_format_silence_64(format);
 548                 memset(data, silence, samples);
 549                 break;
 550         }
 551         case 16: {
 552                 u_int16_t silence = snd_pcm_format_silence_64(format);
 553                 if (! silence)
 554                         memset(data, 0, samples * 2);
 555                 else {
 556                         while (samples-- > 0)
 557                                 *((u_int16_t *)data)++ = silence;
 558                 }
 559                 break;
 560         }
 561         case 24: {
 562                 u_int32_t silence = snd_pcm_format_silence_64(format);
 563                 if (! silence)
 564                         memset(data, 0, samples * 3);
 565                 else {
 566                         while (samples-- > 0) {
 567 #ifdef SNDRV_LITTLE_ENDIAN
 568                                 *((u_int8_t *)data)++ = silence >> 0;
 569                                 *((u_int8_t *)data)++ = silence >> 8;
 570                                 *((u_int8_t *)data)++ = silence >> 16;
 571 #else
 572                                 *((u_int8_t *)data)++ = silence >> 16;
 573                                 *((u_int8_t *)data)++ = silence >> 8;
 574                                 *((u_int8_t *)data)++ = silence >> 0;
 575 #endif
 576                         }
 577                 }
 578                 break;
 579         }
 580         case 32: {
 581                 u_int32_t silence = snd_pcm_format_silence_64(format);
 582                 if (! silence)
 583                         memset(data, 0, samples * 4);
 584                 else {
 585                         while (samples-- > 0)
 586                                 *((u_int32_t *)data)++ = silence;
 587                 }
 588                 break;
 589         }
 590         case 64: {
 591                 u_int64_t silence = snd_pcm_format_silence_64(format);
 592                 if (! silence)
 593                         memset(data, 0, samples * 8);
 594                 else {
 595                         while (samples-- > 0)
 596                                 *((u_int64_t *)data)++ = silence;
 597                 }
 598                 break;
 599         }
 600         default:
 601                 return -EINVAL;
 602         }
 603         return 0;
 604 }
 605
 606 static int linear_formats[4*2*2] = {
 607         SNDRV_PCM_FORMAT_S8,
 608         SNDRV_PCM_FORMAT_S8,
 609         SNDRV_PCM_FORMAT_U8,
 610         SNDRV_PCM_FORMAT_U8,
 611         SNDRV_PCM_FORMAT_S16_LE,
 612         SNDRV_PCM_FORMAT_S16_BE,
 613         SNDRV_PCM_FORMAT_U16_LE,
 614         SNDRV_PCM_FORMAT_U16_BE,
 615         SNDRV_PCM_FORMAT_S24_LE,
 616         SNDRV_PCM_FORMAT_S24_BE,
 617         SNDRV_PCM_FORMAT_U24_LE,
 618         SNDRV_PCM_FORMAT_U24_BE,
 619         SNDRV_PCM_FORMAT_S32_LE,
 620         SNDRV_PCM_FORMAT_S32_BE,
 621         SNDRV_PCM_FORMAT_U32_LE,
 622         SNDRV_PCM_FORMAT_U32_BE
 623 };
 624
 625 /**
 626  * snd_pcm_build_linear_format - return the suitable linear format for the given condition
 627  * @width: the bit-width
 628  * @unsignd: 1 if unsigned, 0 if signed.
 629  * @big_endian: 1 if big-endian, 0 if little-endian
 630  *
 631  * Returns the suitable linear format for the given condition.
 632  */
 633 snd_pcm_format_t snd_pcm_build_linear_format(int width, int unsignd, int big_endian)
 634 {
 635         switch (width) {
 636         case 8:
 637                 width = 0;
 638                 break;
 639         case 16:
 640                 width = 1;
 641                 break;
 642         case 24:
 643                 width = 2;
 644                 break;
 645         case 32:
 646                 width = 3;
 647                 break;
 648         default:
 649                 return SND_PCM_FORMAT_UNKNOWN;
 650         }
 651         return snd_int_to_enum(((int(*)[2][2])linear_formats)[width][!!unsignd][!!big_endian]);
 652 }