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+
+/* -----------------------------------------------------------------------------------------------------------
+Software License for The Fraunhofer FDK AAC Codec Library for Android
+
+© Copyright  1995 - 2012 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
+  All rights reserved.
+
+ 1.    INTRODUCTION
+The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
+the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
+This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
+
+AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
+audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
+independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
+of the MPEG specifications.
+
+Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
+may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
+individually for the purpose of encoding or decoding bit streams in products that are compliant with
+the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
+these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
+software may already be covered under those patent licenses when it is used for those licensed purposes only.
+
+Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
+are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
+applications information and documentation.
+
+2.    COPYRIGHT LICENSE
+
+Redistribution and use in source and binary forms, with or without modification, are permitted without
+payment of copyright license fees provided that you satisfy the following conditions:
+
+You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
+your modifications thereto in source code form.
+
+You must retain the complete text of this software license in the documentation and/or other materials
+provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
+You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
+modifications thereto to recipients of copies in binary form.
+
+The name of Fraunhofer may not be used to endorse or promote products derived from this library without
+prior written permission.
+
+You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
+software or your modifications thereto.
+
+Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
+and the date of any change. For modified versions of the FDK AAC Codec, the term
+"Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
+"Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
+
+3.    NO PATENT LICENSE
+
+NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
+ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
+respect to this software.
+
+You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
+by appropriate patent licenses.
+
+4.    DISCLAIMER
+
+This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
+"AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
+of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
+including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
+or business interruption, however caused and on any theory of liability, whether in contract, strict
+liability, or tort (including negligence), arising in any way out of the use of this software, even if
+advised of the possibility of such damage.
+
+5.    CONTACT INFORMATION
+
+Fraunhofer Institute for Integrated Circuits IIS
+Attention: Audio and Multimedia Departments - FDK AAC LL
+Am Wolfsmantel 33
+91058 Erlangen, Germany
+
+www.iis.fraunhofer.de/amm
+amm-info@iis.fraunhofer.de
+----------------------------------------------------------------------------------------------------------- */
+
+/*!
+  \file
+  \brief  CRC check coutines  
+*/
+
+#include "sbr_crc.h"
+
+#include "FDK_bitstream.h"
+#include "transcendent.h"
+
+#define MAXCRCSTEP    16
+#define MAXCRCSTEP_LD  4
+
+/*!
+  \brief     crc calculation
+*/
+static ULONG
+calcCRC (HANDLE_CRC hCrcBuf, ULONG bValue, int nBits)
+{
+  int i;
+  ULONG bMask = (1UL << (nBits - 1));
+
+  for (i = 0; i < nBits; i++, bMask >>= 1) {
+    USHORT flag = (hCrcBuf->crcState & hCrcBuf->crcMask) ? 1 : 0;
+    USHORT flag1 = (bMask & bValue) ? 1 : 0;
+
+    flag ^= flag1;
+    hCrcBuf->crcState <<= 1;
+    if (flag)
+      hCrcBuf->crcState ^= hCrcBuf->crcPoly;
+  }
+
+  return (hCrcBuf->crcState);
+}
+
+
+/*!
+  \brief     crc
+*/
+static int
+getCrc (HANDLE_FDK_BITSTREAM hBs, ULONG NrBits)
+{
+  int i;
+  CRC_BUFFER CrcBuf;
+
+  CrcBuf.crcState = SBR_CRC_START;
+  CrcBuf.crcPoly  = SBR_CRC_POLY;
+  CrcBuf.crcMask  = SBR_CRC_MASK;
+
+  int CrcStep = NrBits>>MAXCRCSTEP_LD;
+
+  int CrcNrBitsRest = (NrBits - CrcStep * MAXCRCSTEP);
+  ULONG bValue;
+
+  for (i = 0; i < CrcStep; i++) {
+    bValue = FDKreadBits (hBs, MAXCRCSTEP);
+    calcCRC (&CrcBuf, bValue, MAXCRCSTEP);
+  }
+
+  bValue = FDKreadBits (hBs, CrcNrBitsRest);
+  calcCRC (&CrcBuf, bValue, CrcNrBitsRest);
+
+  return (CrcBuf.crcState & SBR_CRC_RANGE);
+
+}
+
+
+/*!
+  \brief   crc interface
+  \return  1: CRC OK, 0: CRC check failure
+*/
+int
+SbrCrcCheck (HANDLE_FDK_BITSTREAM hBs, /*!< handle to bit-buffer  */
+             LONG NrBits)              /*!< max. CRC length       */
+{
+  int crcResult = 1;
+  ULONG NrCrcBits;
+  ULONG crcCheckResult;
+  LONG NrBitsAvailable;
+  ULONG crcCheckSum;
+
+  crcCheckSum = FDKreadBits (hBs, 10);
+
+  NrBitsAvailable = FDKgetValidBits(hBs);
+  if (NrBitsAvailable <= 0){
+    return 0;
+  }
+
+  NrCrcBits = fixMin ((INT)NrBits, (INT)NrBitsAvailable);
+
+  crcCheckResult = getCrc (hBs, NrCrcBits);
+  FDKpushBack(hBs, (NrBitsAvailable - FDKgetValidBits(hBs)) );
+
+
+  if (crcCheckResult != crcCheckSum) {
+    crcResult = 0;
+  }
+
+  return (crcResult);
+}