libFDK/src/FDK_bitbuffer.cpp

   1
   2 /* -----------------------------------------------------------------------------------------------------------
   3 Software License for The Fraunhofer FDK AAC Codec Library for Android
   4
   5 © Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
   6   All rights reserved.
   7
   8  1.    INTRODUCTION
   9 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
  10 the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
  11 This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
  12
  13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
  14 audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
  15 independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
  16 of the MPEG specifications.
  17
  18 Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
  19 may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
  20 individually for the purpose of encoding or decoding bit streams in products that are compliant with
  21 the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
  22 these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
  23 software may already be covered under those patent licenses when it is used for those licensed purposes only.
  24
  25 Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
  26 are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
  27 applications information and documentation.
  28
  29 2.    COPYRIGHT LICENSE
  30
  31 Redistribution and use in source and binary forms, with or without modification, are permitted without
  32 payment of copyright license fees provided that you satisfy the following conditions:
  33
  34 You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
  35 your modifications thereto in source code form.
  36
  37 You must retain the complete text of this software license in the documentation and/or other materials
  38 provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
  39 You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
  40 modifications thereto to recipients of copies in binary form.
  41
  42 The name of Fraunhofer may not be used to endorse or promote products derived from this library without
  43 prior written permission.
  44
  45 You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
  46 software or your modifications thereto.
  47
  48 Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
  49 and the date of any change. For modified versions of the FDK AAC Codec, the term
  50 "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
  51 "Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
  52
  53 3.    NO PATENT LICENSE
  54
  55 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
  56 ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
  57 respect to this software.
  58
  59 You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
  60 by appropriate patent licenses.
  61
  62 4.    DISCLAIMER
  63
  64 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
  65 "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
  66 of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  67 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
  68 including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
  69 or business interruption, however caused and on any theory of liability, whether in contract, strict
  70 liability, or tort (including negligence), arising in any way out of the use of this software, even if
  71 advised of the possibility of such damage.
  72
  73 5.    CONTACT INFORMATION
  74
  75 Fraunhofer Institute for Integrated Circuits IIS
  76 Attention: Audio and Multimedia Departments - FDK AAC LL
  77 Am Wolfsmantel 33
  78 91058 Erlangen, Germany
  79
  80 www.iis.fraunhofer.de/amm
  81 amm-info@iis.fraunhofer.de
  82 ----------------------------------------------------------------------------------------------------------- */
  83
  84 /***************************  Fraunhofer IIS FDK Tools  ***********************
  85
  86    Author(s):   M. Lohwasser
  87    Description: common bitbuffer read/write routines
  88
  89 ******************************************************************************/
  90
  91 #include "FDK_bitbuffer.h"
  92
  93
  94
  95
  96 #include "genericStds.h"
  97 #include "common_fix.h"
  98 #include "fixminmax.h"
  99
 100 const UINT BitMask [32+1] =
 101 {
 102          0x0,        0x1,        0x3,        0x7,
 103          0xf,       0x1f,       0x3f,       0x7f,
 104         0xff,      0x1ff,      0x3ff,      0x7ff,
 105        0xfff,     0x1fff,     0x3fff,     0x7fff,
 106       0xffff,    0x1ffff,    0x3ffff,    0x7ffff,
 107      0xfffff,   0x1fffff,   0x3fffff,   0x7fffff,
 108     0xffffff,  0x1ffffff,  0x3ffffff,  0x7ffffff,
 109    0xfffffff, 0x1fffffff, 0x3fffffff, 0x7fffffff,
 110   0xffffffff
 111 };
 112
 113 const UINT *const RESTRICT pBitMask = BitMask;
 114
 115 void FDK_CreateBitBuffer (HANDLE_FDK_BITBUF *hBitBuf, UCHAR *pBuffer,
 116                           UINT bufSize)
 117 {
 118    FDK_InitBitBuffer (*hBitBuf, pBuffer, bufSize, 0);
 119
 120    FDKmemclear((*hBitBuf)->Buffer, bufSize*sizeof(UCHAR));
 121 }
 122
 123 void FDK_DeleteBitBuffer (HANDLE_FDK_BITBUF hBitBuf) { ; }
 124
 125 void FDK_InitBitBuffer (HANDLE_FDK_BITBUF hBitBuf, UCHAR *pBuffer,
 126                         UINT bufSize, UINT validBits)
 127 {
 128    hBitBuf->ValidBits   = validBits ;
 129    hBitBuf->ReadOffset  = 0 ;
 130    hBitBuf->WriteOffset = 0 ;
 131    hBitBuf->BitCnt      = 0 ;
 132    hBitBuf->BitNdx      = 0 ;
 133
 134    hBitBuf->Buffer      = pBuffer ;
 135    hBitBuf->bufSize     = bufSize ;
 136    hBitBuf->bufBits     = (bufSize << 3) ;
 137 #if defined(FDK_DEBUG) || defined(DEBUG)
 138    /*assure bufsize (2^n) */
 139    if (bufSize!=0) {
 140      UINT x = 0, n=bufSize;
 141      for (x=0; n>0; x++,n>>=1) {}
 142      if ( bufSize != (1<<(x-1)) ) {
 143        FDKprintfErr("Error: bufSizein FDK_InitBitBuffer() != (2^n), %d\n", bufSize);
 144      }
 145    }
 146 #endif
 147 }
 148
 149 void FDK_ResetBitBuffer ( HANDLE_FDK_BITBUF hBitBuf )
 150 {
 151    hBitBuf->ValidBits   = 0 ;
 152    hBitBuf->ReadOffset  = 0 ;
 153    hBitBuf->WriteOffset = 0 ;
 154    hBitBuf->BitCnt      = 0 ;
 155    hBitBuf->BitNdx      = 0 ;
 156 }
 157
 158 INT  FDK_get (HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits)
 159 {
 160   UINT byteOffset = hBitBuf->BitNdx >> 3 ;
 161   UINT bitOffset  = hBitBuf->BitNdx & 0x07 ;
 162
 163   hBitBuf->BitNdx     = (hBitBuf->BitNdx + numberOfBits) & (hBitBuf->bufBits - 1) ;
 164   hBitBuf->BitCnt    +=  numberOfBits ;
 165   hBitBuf->ValidBits -=  numberOfBits ;
 166
 167   UINT byteMask = hBitBuf->bufSize - 1 ;
 168
 169   UINT tx = (hBitBuf->Buffer [ byteOffset    & byteMask] << 24) |
 170             (hBitBuf->Buffer [(byteOffset+1) & byteMask] << 16) |
 171             (hBitBuf->Buffer [(byteOffset+2) & byteMask] <<  8) |
 172              hBitBuf->Buffer [(byteOffset+3) & byteMask];
 173
 174   if (bitOffset)
 175   {
 176     tx <<= bitOffset;
 177     tx |= hBitBuf->Buffer [(byteOffset+4) & byteMask] >> (8-bitOffset);
 178   }
 179
 180   return (tx >> (32 - numberOfBits)) ;
 181 }
 182
 183 INT FDK_get32 (HANDLE_FDK_BITBUF hBitBuf)
 184 {
 185   UINT BitNdx = hBitBuf->BitNdx + 32;
 186   if (BitNdx <= hBitBuf->bufBits)
 187   {
 188     hBitBuf->BitNdx = BitNdx;
 189     hBitBuf->BitCnt +=  32;
 190     hBitBuf->ValidBits -= 32;
 191
 192     UINT byteOffset = (BitNdx-1) >> 3;
 193     UINT cache = (hBitBuf->Buffer[(byteOffset-3)] << 24) |
 194                  (hBitBuf->Buffer[(byteOffset-2)] << 16) |
 195                  (hBitBuf->Buffer[(byteOffset-1)] <<  8) |
 196                   hBitBuf->Buffer[(byteOffset-0)];
 197
 198     if ( (BitNdx = (BitNdx&7)) != 0 ) {
 199       cache = (cache >> (8-BitNdx)) | ((UINT)hBitBuf->Buffer [byteOffset-4] << (24+BitNdx));
 200     }
 201     return (cache) ;
 202   }
 203   else
 204   {
 205     /* exotic path, used only at the end of the buffer, when wrapping around */
 206     int nBits = (INT)hBitBuf->bufBits-(INT)hBitBuf->BitNdx;
 207
 208     UINT cache = FDK_get (hBitBuf,nBits)<< (32-nBits);
 209     cache |= (FDK_get (hBitBuf,32-nBits));
 210     return (cache);
 211   }
 212 }
 213
 214 INT FDK_getBwd (HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits)
 215 {
 216   UINT byteOffset = hBitBuf->BitNdx >> 3 ;
 217   UINT bitOffset  = hBitBuf->BitNdx & 0x07 ;
 218   UINT byteMask   = hBitBuf->bufSize - 1 ;
 219   int i;
 220
 221   hBitBuf->BitNdx     = (hBitBuf->BitNdx - numberOfBits) & (hBitBuf->bufBits - 1) ;
 222   hBitBuf->BitCnt    -=  numberOfBits ;
 223   hBitBuf->ValidBits +=  numberOfBits ;
 224
 225   UINT tx = hBitBuf->Buffer [(byteOffset-3) & byteMask] << 24 |
 226             hBitBuf->Buffer [(byteOffset-2) & byteMask] << 16 |
 227             hBitBuf->Buffer [(byteOffset-1) & byteMask] <<  8 |
 228             hBitBuf->Buffer [ byteOffset    & byteMask] ;
 229   UINT txa = 0x0;
 230
 231   tx >>= (8 - bitOffset) ;
 232
 233   if (bitOffset && numberOfBits > 24)
 234   {
 235     tx |= hBitBuf->Buffer [(byteOffset-4) & byteMask] << (24 + bitOffset) ;
 236   }
 237
 238   /* in place turn around */
 239   for (i = 0; i < 16; i++) {
 240     UINT bitMaskR = 0x00000001 << i;
 241     UINT bitMaskL = 0x80000000 >> i;
 242
 243     txa |= (tx & bitMaskR) << (31 - (i<<1));
 244     txa |= (tx & bitMaskL) >> (31 - (i<<1));
 245   }
 246
 247   return (txa >> (32 - numberOfBits)) ;
 248 }
 249
 250 void FDK_put (HANDLE_FDK_BITBUF hBitBuf, UINT value, const UINT numberOfBits)
 251 {
 252   UINT byteOffset = hBitBuf->BitNdx >> 3 ;
 253   UINT bitOffset  = hBitBuf->BitNdx & 0x07 ;
 254
 255   hBitBuf->BitNdx     = (hBitBuf->BitNdx + numberOfBits) & (hBitBuf->bufBits - 1) ;
 256   hBitBuf->BitCnt    +=  numberOfBits ;
 257   hBitBuf->ValidBits +=  numberOfBits ;
 258
 259   UINT byteMask = hBitBuf->bufSize - 1 ;
 260
 261   UINT tmp  = value<<(32-numberOfBits)>>bitOffset;
 262   UINT mask = ~BitMask[(32-bitOffset)] | (BitMask [(32-numberOfBits)] >> bitOffset) ;
 263
 264   hBitBuf->Buffer [ byteOffset    & byteMask]  = (hBitBuf->Buffer [ byteOffset    & byteMask]&(mask>>24)) | (UCHAR)(tmp>>24);
 265   hBitBuf->Buffer [(byteOffset+1) & byteMask]  = (hBitBuf->Buffer [(byteOffset+1) & byteMask]&(mask>>16)) | (UCHAR)(tmp>>16);
 266   hBitBuf->Buffer [(byteOffset+2) & byteMask]  = (hBitBuf->Buffer [(byteOffset+2) & byteMask]&(mask>>8))  | (UCHAR)(tmp>>8);
 267   hBitBuf->Buffer [(byteOffset+3) & byteMask]  = (hBitBuf->Buffer [(byteOffset+3) & byteMask]&(mask))     | (UCHAR)(tmp);
 268
 269   if (bitOffset && numberOfBits > 24)
 270   {
 271     hBitBuf->Buffer [(byteOffset+4) & byteMask]  = (UCHAR)(value<<(40-numberOfBits)>>bitOffset) |
 272                ( hBitBuf->Buffer [(byteOffset+4) & byteMask] & BitMask[(40-numberOfBits-bitOffset)] ) ;
 273   }
 274 }
 275
 276 void FDK_putBwd (HANDLE_FDK_BITBUF hBitBuf, UINT value, const UINT numberOfBits)
 277 {
 278   UINT byteOffset = hBitBuf->BitNdx >> 3 ;
 279   UINT bitOffset  = 7 - (hBitBuf->BitNdx & 0x07) ;
 280   UINT byteMask   = hBitBuf->bufSize - 1 ;
 281
 282   UINT mask = ~(BitMask[numberOfBits] << bitOffset) ;
 283   UINT tmp = 0x0000;
 284   int  i;
 285
 286   hBitBuf->BitNdx     = (hBitBuf->BitNdx - numberOfBits) & (hBitBuf->bufBits - 1) ;
 287   hBitBuf->BitCnt    -=  numberOfBits ;
 288   hBitBuf->ValidBits -=  numberOfBits ;
 289
 290   /* in place turn around */
 291   for (i = 0; i < 16; i++) {
 292     UINT bitMaskR = 0x00000001 << i;
 293     UINT bitMaskL = 0x80000000 >> i;
 294
 295     tmp |= (value & bitMaskR) << (31 - (i<<1));
 296     tmp |= (value & bitMaskL) >> (31 - (i<<1));
 297   }
 298   value = tmp;
 299   tmp   = value>>(32-numberOfBits)<<bitOffset;
 300
 301   hBitBuf->Buffer [ byteOffset    & byteMask]  = (hBitBuf->Buffer [ byteOffset    & byteMask]&(mask))     | (UCHAR)(tmp);
 302   hBitBuf->Buffer [(byteOffset-1) & byteMask]  = (hBitBuf->Buffer [(byteOffset-1) & byteMask]&(mask>>8))  | (UCHAR)(tmp>>8);
 303   hBitBuf->Buffer [(byteOffset-2) & byteMask]  = (hBitBuf->Buffer [(byteOffset-2) & byteMask]&(mask>>16)) | (UCHAR)(tmp>>16);
 304   hBitBuf->Buffer [(byteOffset-3) & byteMask]  = (hBitBuf->Buffer [(byteOffset-3) & byteMask]&(mask>>24)) | (UCHAR)(tmp>>24);
 305
 306   if ((bitOffset + numberOfBits) > 32)
 307   {
 308     hBitBuf->Buffer [(byteOffset-4) & byteMask]  = (UCHAR)(value>>(64-numberOfBits-bitOffset)) |
 309                ( hBitBuf->Buffer [(byteOffset-4) & byteMask] & ~(BitMask[bitOffset] >> (32-numberOfBits)) ) ;
 310   }
 311 }
 312
 313
 314 void FDK_pushBack (HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits, UCHAR config)
 315 {
 316   hBitBuf->BitCnt    -= numberOfBits ;
 317   hBitBuf->ValidBits += (config==0) ? numberOfBits : (-(INT)numberOfBits) ;
 318   hBitBuf->BitNdx     = (hBitBuf->BitNdx - numberOfBits) & (hBitBuf->bufBits - 1) ;
 319 }
 320
 321 void FDK_pushForward (HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits, UCHAR config)
 322 {
 323   hBitBuf->BitCnt    += numberOfBits ;
 324   hBitBuf->ValidBits -= (config==0) ? numberOfBits : (-(INT)numberOfBits) ;
 325   hBitBuf->BitNdx     = (hBitBuf->BitNdx + numberOfBits) & (hBitBuf->bufBits - 1) ;
 326 }
 327
 328
 329 void FDK_byteAlign (HANDLE_FDK_BITBUF hBitBuf, UCHAR config)
 330 {
 331   INT alignment = hBitBuf->BitCnt & 0x07 ;
 332
 333   if (alignment)
 334   {
 335     if (config==0)
 336       FDK_pushForward (hBitBuf, 8 - alignment, config) ; /* BS_READER */
 337     else
 338       FDK_put (hBitBuf,0 , 8 - alignment) ;              /* BS_WRITER */
 339   }
 340
 341   hBitBuf->BitCnt = 0 ;
 342 }
 343
 344 UINT FDK_getValidBits (HANDLE_FDK_BITBUF hBitBuf)
 345 {
 346     return hBitBuf->ValidBits;
 347 }
 348
 349 INT FDK_getFreeBits (HANDLE_FDK_BITBUF hBitBuf)
 350 {
 351     return (hBitBuf->bufBits - hBitBuf->ValidBits) ;
 352 }
 353
 354 void FDK_setBitCnt (HANDLE_FDK_BITBUF hBitBuf, const UINT value)
 355 {
 356   hBitBuf->BitCnt = value ;
 357 }
 358
 359 INT FDK_getBitCnt (HANDLE_FDK_BITBUF hBitBuf)
 360 {
 361   return hBitBuf->BitCnt ;
 362 }
 363
 364 void FDK_Feed(HANDLE_FDK_BITBUF hBitBuf,
 365               UCHAR            *RESTRICT inputBuffer,
 366               const UINT        bufferSize,
 367               UINT             *bytesValid)
 368 {
 369   inputBuffer = &inputBuffer [bufferSize - *bytesValid] ;
 370
 371   UINT bTotal = 0 ;
 372
 373   UINT bToRead   = (hBitBuf->bufBits - hBitBuf->ValidBits) >> 3 ;
 374   UINT noOfBytes = fMin(bToRead, *bytesValid); //(bToRead < *bytesValid) ? bToRead : *bytesValid ;
 375
 376   while (noOfBytes > 0)
 377   {
 378     /* split read to buffer size */
 379     bToRead = hBitBuf->bufSize - hBitBuf->ReadOffset ;
 380     bToRead = fMin(bToRead, noOfBytes); //(bToRead < noOfBytes) ? bToRead : noOfBytes ;
 381
 382     /* copy 'bToRead' bytes from 'ptr' to inputbuffer */
 383     FDKmemcpy(&hBitBuf->Buffer[hBitBuf->ReadOffset], inputBuffer, bToRead*sizeof(UCHAR));
 384
 385     /* add noOfBits to number of valid bits in buffer */
 386     hBitBuf->ValidBits  += bToRead << 3 ;
 387     bTotal       += bToRead ;
 388     inputBuffer  += bToRead ;
 389
 390     hBitBuf->ReadOffset  = (hBitBuf->ReadOffset + bToRead) & (hBitBuf->bufSize - 1) ;
 391     noOfBytes    -= bToRead ;
 392   }
 393
 394   *bytesValid -= bTotal ;
 395 }
 396
 397 void CopyAlignedBlock (HANDLE_FDK_BITBUF h_BitBufSrc, UCHAR *RESTRICT dstBuffer, UINT bToRead)
 398 {
 399   UINT byteOffset = h_BitBufSrc->BitNdx >> 3 ;
 400   const UINT byteMask = h_BitBufSrc->bufSize - 1 ;
 401
 402   UCHAR *RESTRICT pBBB = h_BitBufSrc->Buffer;
 403   for (UINT i = 0 ; i < bToRead ; i++)
 404   {
 405     dstBuffer[i] = pBBB[(byteOffset+i) & byteMask] ;
 406   }
 407
 408   bToRead <<= 3 ;
 409
 410   h_BitBufSrc->BitNdx = (h_BitBufSrc->BitNdx + bToRead) & (h_BitBufSrc->bufBits - 1) ;
 411   h_BitBufSrc->BitCnt += bToRead ;
 412   h_BitBufSrc->ValidBits -= bToRead ;
 413 }
 414
 415 void FDK_Copy (HANDLE_FDK_BITBUF h_BitBufDst, HANDLE_FDK_BITBUF h_BitBufSrc, UINT *bytesValid)
 416 {
 417   INT bTotal = 0;
 418
 419   /* limit noOfBytes to valid bytes in src buffer and available bytes in dst buffer */
 420   UINT bToRead   = h_BitBufSrc->ValidBits >> 3 ;
 421   UINT noOfBytes = fMin(bToRead, *bytesValid); //(*bytesValid < bToRead) ? *bytesValid : bToRead ;
 422   bToRead   = FDK_getFreeBits(h_BitBufDst);
 423   noOfBytes = fMin(bToRead, noOfBytes); //(bToRead < noOfBytes) ? bToRead : noOfBytes;
 424
 425   while (noOfBytes > 0)
 426   {
 427     /* Split Read to buffer size */
 428     bToRead = h_BitBufDst->bufSize - h_BitBufDst->ReadOffset ;
 429     bToRead = fMin(noOfBytes, bToRead); //(noOfBytes < bToRead) ? noOfBytes : bToRead ;
 430
 431     /* copy 'bToRead' bytes from buffer to buffer */
 432     if (!(h_BitBufSrc->BitNdx & 0x07)) {
 433       CopyAlignedBlock (h_BitBufSrc, h_BitBufDst->Buffer + h_BitBufDst->ReadOffset, bToRead) ;
 434     } else {
 435       for (UINT i = 0; i < bToRead; i++)
 436       {
 437         h_BitBufDst->Buffer [h_BitBufDst->ReadOffset + i] = (UCHAR)FDK_get(h_BitBufSrc,8);
 438       }
 439     }
 440
 441     /* add noOfBits to number of valid bits in buffer */
 442     h_BitBufDst->ValidBits  += bToRead << 3 ;
 443     bTotal       += bToRead;
 444
 445     h_BitBufDst->ReadOffset  = (h_BitBufDst->ReadOffset + bToRead) & (h_BitBufDst->bufSize-1);
 446     noOfBytes    -= bToRead;
 447   }
 448
 449   *bytesValid -=bTotal;
 450 }
 451
 452 void FDK_Fetch (HANDLE_FDK_BITBUF hBitBuf, UCHAR *outBuf, UINT *writeBytes)
 453 {
 454   UCHAR *RESTRICT outputBuffer = outBuf;
 455   UINT bTotal = 0 ;
 456
 457   UINT bToWrite  = (hBitBuf->ValidBits) >> 3 ;
 458   UINT noOfBytes = fMin(bToWrite, *writeBytes); //(bToWrite < *writeBytes) ? bToWrite : *writeBytes ;
 459
 460   while (noOfBytes > 0)
 461   {
 462     /* split write to buffer size */
 463     bToWrite = hBitBuf->bufSize - hBitBuf->WriteOffset ;
 464     bToWrite = fMin(bToWrite, noOfBytes); //(bToWrite < noOfBytes) ? bToWrite : noOfBytes ;
 465
 466     /* copy 'bToWrite' bytes from bitbuffer to outputbuffer */
 467     FDKmemcpy(outputBuffer, &hBitBuf->Buffer[hBitBuf->WriteOffset], bToWrite*sizeof(UCHAR));
 468
 469     /* sub noOfBits from number of valid bits in buffer */
 470     hBitBuf->ValidBits  -= bToWrite << 3 ;
 471     bTotal       += bToWrite ;
 472     outputBuffer += bToWrite ;
 473
 474     hBitBuf->WriteOffset  = (hBitBuf->WriteOffset + bToWrite) & (hBitBuf->bufSize - 1) ;
 475     noOfBytes    -= bToWrite ;
 476   }
 477
 478   *writeBytes = bTotal ;
 479 }
 480