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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
+----------------------------------------------------------------------------------------------------------- */
+
+/***************************  Fraunhofer IIS FDK Tools  **********************
+
+   Author(s):   Haricharan Lakshman, Manuel Jander
+   Description: Trigonometric functions fixed point fractional implementation.
+
+******************************************************************************/
+
+#include "FDK_trigFcts.h"
+
+#include "fixpoint_math.h"
+
+
+
+
+#define IMPROVE_ATAN2_ACCURACY  1  // 0 --> 59 dB SNR     1 --> 65 dB SNR
+#define MINSFTAB  7
+#define MAXSFTAB 25
+
+#if IMPROVE_ATAN2_ACCURACY
+static const FIXP_DBL f_atan_expand_range[MAXSFTAB-(MINSFTAB-1)]  =
+{
+  /*****************************************************************************
+   *
+   *  Table holds fixp_atan() output values which are outside of input range
+   *  of fixp_atan() to improve SNR of fixp_atan2().
+   *
+   *  This Table might also be used in fixp_atan() [todo] so there a wider input
+   *  range can be covered, too.
+   *
+   *  Matlab (generate table):
+   *    for scl = 7:25            % MINSFTAB .. MAXSFTAB
+   *      at=atan(0.5 *(2^scl));  % 0.5 because get in 'middle' area of current scale level 'scl'
+   *      at/2                    % div at by ATO_SCALE
+   *    end
+   *
+   *  Table divided by 2=ATO_SCALE  <--  SF=ATO_SF
+   *****************************************************************************/
+   FL2FXCONST_DBL(7.775862990872099e-001), FL2FXCONST_DBL(7.814919928673978e-001), FL2FXCONST_DBL(7.834450483314648e-001),
+   FL2FXCONST_DBL(7.844216021392089e-001), FL2FXCONST_DBL(7.849098823026687e-001), FL2FXCONST_DBL(7.851540227918509e-001),
+   FL2FXCONST_DBL(7.852760930873737e-001), FL2FXCONST_DBL(7.853371282415015e-001), FL2FXCONST_DBL(7.853676458193612e-001),
+   FL2FXCONST_DBL(7.853829046083906e-001), FL2FXCONST_DBL(7.853905340029177e-001), FL2FXCONST_DBL(7.853943487001828e-001),
+   FL2FXCONST_DBL(7.853962560488155e-001), FL2FXCONST_DBL(7.853972097231319e-001), FL2FXCONST_DBL(7.853976865602901e-001),
+   FL2FXCONST_DBL(7.853979249788692e-001), FL2FXCONST_DBL(7.853980441881587e-001), FL2FXCONST_DBL(7.853981037928035e-001),
+   FL2FXCONST_DBL(7.853981335951259e-001)
+   //     pi/4 = 0.785398163397448 = pi/2/ATO_SCALE
+};
+#endif
+
+FIXP_DBL fixp_atan2(FIXP_DBL y, FIXP_DBL x)
+{
+    FIXP_DBL q;
+    FIXP_DBL at;  // atan  out
+    FIXP_DBL at2; // atan2 out
+    FIXP_DBL ret = FL2FXCONST_DBL(-1.0f);
+    INT sf,sfo,stf;
+
+    // --- division
+
+    if      (y > FL2FXCONST_DBL(0.0f))
+    {
+        if      (x > FL2FXCONST_DBL(0.0f)) {
+                                           q =  fDivNormHighPrec( y, x, &sf); // both pos.
+        }
+        else if (x < FL2FXCONST_DBL(0.0f)) {
+                                           q = -fDivNormHighPrec( y,-x, &sf); // x neg.
+        }
+        else {//(x ==FL2FXCONST_DBL(0.0f))
+                                           q =  FL2FXCONST_DBL(+1.0f);  // y/x = pos/zero = +Inf
+                                           sf = 0;
+        }
+    }
+    else if (y < FL2FXCONST_DBL(0.0f))
+    {
+        if      (x > FL2FXCONST_DBL(0.0f)) {
+                                           q = -fDivNormHighPrec(-y, x, &sf); // y neg.
+        }
+        else if (x < FL2FXCONST_DBL(0.0f)) {
+                                           q =  fDivNormHighPrec(-y,-x, &sf); // both neg.
+        }
+        else {//(x ==FL2FXCONST_DBL(0.0f))
+                                           q =  FL2FXCONST_DBL(-1.0f);  // y/x = neg/zero = -Inf
+                                           sf = 0;
+        }
+    }
+    else { // (y ==FL2FXCONST_DBL(0.0f))
+        q = FL2FXCONST_DBL(0.0f);
+        sf = 0;
+    }
+    sfo = sf;
+
+    // --- atan()
+
+    if  ( sfo > ATI_SF ) {
+        // --- could not calc fixp_atan() here bec of input data out of range
+        //     ==> therefore give back boundary values
+
+        #if IMPROVE_ATAN2_ACCURACY
+        if (sfo > MAXSFTAB) sfo = MAXSFTAB;
+        #endif
+
+        if      (  q > FL2FXCONST_DBL(0.0f) ) {
+           #if IMPROVE_ATAN2_ACCURACY
+            at = +f_atan_expand_range[sfo-ATI_SF-1];
+           #else
+            at = FL2FXCONST_DBL( +M_PI/2 / ATO_SCALE);
+           #endif
+        }
+        else if (  q < FL2FXCONST_DBL(0.0f) ) {
+           #if IMPROVE_ATAN2_ACCURACY
+            at = -f_atan_expand_range[sfo-ATI_SF-1];
+           #else
+            at = FL2FXCONST_DBL( -M_PI/2 / ATO_SCALE);
+           #endif
+        }
+        else {  // q== FL2FXCONST_DBL(0.0f)
+            at = FL2FXCONST_DBL( 0.0f );
+        }
+    }else{
+        // --- calc of fixp_atan() is possible; input data within range
+        //     ==> set q on fixed scale level as desired from fixp_atan()
+        stf = sfo - ATI_SF;
+        if (stf > 0)  q = q << (INT)fMin( stf,DFRACT_BITS-1);
+        else          q = q >> (INT)fMin(-stf,DFRACT_BITS-1);
+        at = fixp_atan(q);  // ATO_SF
+    }
+
+    // --- atan2()
+
+    at2 = at >> (AT2O_SF - ATO_SF); // now AT2O_SF for atan2
+    if      (  x > FL2FXCONST_DBL(0.0f) ) {
+        ret = at2;
+    }
+    else if (  x < FL2FXCONST_DBL(0.0f) ) {
+        if (  y >= FL2FXCONST_DBL(0.0f) ) {
+            ret = at2 + FL2FXCONST_DBL( M_PI / AT2O_SCALE);
+        } else {
+            ret = at2 - FL2FXCONST_DBL( M_PI / AT2O_SCALE);
+        }
+    }
+    else {
+        // x == 0
+        if      ( y >  FL2FXCONST_DBL(0.0f) ) {
+            ret = FL2FXCONST_DBL( +M_PI/2 / AT2O_SCALE);
+        }
+        else if ( y <  FL2FXCONST_DBL(0.0f) ) {
+            ret = FL2FXCONST_DBL( -M_PI/2 / AT2O_SCALE);
+        }
+        else if ( y == FL2FXCONST_DBL(0.0f) ) {
+            ret = FL2FXCONST_DBL(0.0f);
+        }
+    }
+    return ret;
+}
+
+
+FIXP_DBL fixp_atan(FIXP_DBL x)
+{
+    INT sign;
+    FIXP_DBL result, temp;
+
+    // SNR of fixp_atan() = 56 dB
+    FIXP_DBL ONEBY3P56  = (FIXP_DBL)0x26800000; // 1.0/3.56 in q31
+    FIXP_DBL P281       = (FIXP_DBL)0x00013000; // 0.281 in q18
+    FIXP_DBL ONEP571    = (FIXP_DBL)0x6487ef00; // 1.571 in q30
+
+    if (x < FIXP_DBL(0)) {
+      sign = 1;
+      x = - x ;
+    } else {
+      sign = 0;
+    }
+
+    /* calc of arctan */
+    if(x < ( Q(Q_ATANINP)-FL2FXCONST_DBL(0.00395)) )
+    {
+        INT res_e;
+
+        temp = fPow2(x);            // q25 * q25 - (DFRACT_BITS-1) = q19
+        temp = fMult(temp, ONEBY3P56);      // q19 * q31 - (DFRACT_BITS-1) = q19
+        temp = temp + Q(19);                // q19 + q19 = q19
+        result = fDivNorm(x, temp, &res_e);
+        result = scaleValue(result, (Q_ATANOUT-Q_ATANINP+19-DFRACT_BITS+1) + res_e  );
+    }
+    else if( x < FL2FXCONST_DBL(1.28/64.0) )
+    {
+        FIXP_DBL delta_fix;
+        FIXP_DBL PI_BY_4 = FL2FXCONST_DBL(3.1415926/4.0) >> 1; /* pi/4 in q30 */
+
+        delta_fix = (x - FL2FXCONST_DBL(1.0/64.0)) << 5; /* q30 */
+        result = PI_BY_4 + (delta_fix >> 1) - (fPow2Div2(delta_fix));
+    }
+    else
+    {
+        INT res_e;
+
+        temp = fPow2Div2(x);        // q25 * q25 - (DFRACT_BITS-1) - 1 = q18
+        temp = temp + P281;                 // q18 + q18 = q18
+        result = fDivNorm(x, temp, &res_e);
+        result = scaleValue(result, (Q_ATANOUT-Q_ATANINP+18-DFRACT_BITS+1) + res_e );
+        result = ONEP571 - result;          // q30 + q30 = q30
+    }
+    if (sign) {
+      result = -result;
+    }
+
+    return(result);
+}
+
+
+
+#include "FDK_tools_rom.h"
+
+FIXP_DBL fixp_cos(FIXP_DBL x, int scale)
+{
+    FIXP_DBL residual, error, sine, cosine;
+    
+    residual = fixp_sin_cos_residual_inline(x, scale, &sine, &cosine);
+    error = fMult(sine, residual);
+
+    return cosine - error;
+}
+
+FIXP_DBL fixp_sin(FIXP_DBL x, int scale)
+{
+    FIXP_DBL residual, error, sine, cosine;
+    
+    residual = fixp_sin_cos_residual_inline(x, scale, &sine, &cosine);
+    error = fMult(cosine, residual);
+
+    return sine + error;
+}
+
+void fixp_cos_sin (FIXP_DBL x, int scale, FIXP_DBL *cos, FIXP_DBL *sin)
+{
+    FIXP_DBL residual, error0, error1, sine, cosine;
+    
+    residual = fixp_sin_cos_residual_inline(x, scale, &sine, &cosine);
+    error0 = fMult(sine, residual);
+    error1 = fMult(cosine, residual);
+    *cos  = cosine - error0;
+    *sin  = sine + error1;
+}
+
+
+
+
+