arm-hybrid-22k/lib_src/eas_chorus.c - platform/external/sonivox - Git at Google

 /*----------------------------------------------------------------------------
  *
  * File:
  * eas_chorus.c
  *
  * Contents and purpose:
  * Contains the implementation of the Chorus effect.
  *
  *
  * Copyright Sonic Network Inc. 2006

  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  *----------------------------------------------------------------------------
  * Revision Control:
  *   $Revision: 499 $
  *   $Date: 2006-12-11 16:07:20 -0800 (Mon, 11 Dec 2006) $
  *----------------------------------------------------------------------------
 */

 #include "eas_data.h"
 #include "eas_effects.h"
 #include "eas_math.h"
 #include "eas_chorusdata.h"
 #include "eas_chorus.h"
 #include "eas_config.h"
 #include "eas_host.h"
 #include "eas_report.h"

 /* prototypes for effects interface */
 static EAS_RESULT ChorusInit (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR *pInstData);
 static void ChorusProcess (EAS_VOID_PTR pInstData, EAS_PCM *pSrc, EAS_PCM *pDst, EAS_I32 numSamples);
 static EAS_RESULT ChorusShutdown (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR pInstData);
 static EAS_RESULT ChorusGetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 *pValue);
 static EAS_RESULT ChorusSetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 value);

 /* common effects interface for configuration module */
 const S_EFFECTS_INTERFACE EAS_Chorus =
 {
     ChorusInit,
     ChorusProcess,
     ChorusShutdown,
     ChorusGetParam,
     ChorusSetParam
 };


 //LFO shape table used by the chorus, larger table would sound better
 //this is a sine wave, where 32767 = 1.0
 static const EAS_I16 EAS_chorusShape[CHORUS_SHAPE_SIZE] = {
     0, 1608, 3212, 4808, 6393, 7962, 9512, 11309, 12539, 14010, 15446, 16846, 18204, 19519, 20787, 22005, 23170,
     24279, 25329, 26319, 27245, 28105, 28898, 29621, 30273, 30852, 31356, 31785, 32137, 32412, 32609, 32728,
     32767, 32728, 32609, 32412, 32137, 31785, 31356, 30852, 30273, 29621, 28898, 28105, 27245, 26319, 25329,
     24279, 23170, 22005, 20787, 19519, 18204, 16846, 15446, 14010, 12539, 11039, 9512, 7962, 6393, 4808, 3212,
     1608, 0, -1608, -3212, -4808, -6393, -7962, -9512, -11309, -12539, -14010, -15446, -16846, -18204, -19519,
     -20787, -22005, -23170, -24279, -25329, -26319, -27245, -28105, -28898, -29621, -30273, -30852, -31356, -31785,
     -32137, -32412, -32609, -32728, -32767, -32728, -32609, -32412, -32137, -31785, -31356, -30852, -30273, -29621,
     -28898, -28105, -27245, -26319, -25329, -24279, -23170, -22005, -20787, -19519, -18204, -16846, -15446, -14010,
     -12539, -11039, -9512, -7962, -6393, -4808, -3212, -1608
 };

 /*----------------------------------------------------------------------------
  * InitializeChorus()
  *----------------------------------------------------------------------------
  * Purpose: Initializes chorus parameters
  *
  *
  * Inputs:
  *
  * Outputs:
  *
  *----------------------------------------------------------------------------
 */
 static EAS_RESULT ChorusInit (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR *pInstData)
 {
     S_CHORUS_OBJECT *pChorusData;
     S_CHORUS_PRESET *pPreset;
     EAS_I32 index;

     /* check Configuration Module for data allocation */
     if (pEASData->staticMemoryModel)
         pChorusData = EAS_CMEnumFXData(EAS_MODULE_CHORUS);

     /* allocate dynamic memory */
     else
         pChorusData = EAS_HWMalloc(pEASData->hwInstData, sizeof(S_CHORUS_OBJECT));

     if (pChorusData == NULL)
     {
         { /* dpp: EAS_ReportEx(_EAS_SEVERITY_FATAL, "Failed to allocate Chorus memory\n"); */ }
         return EAS_ERROR_MALLOC_FAILED;
     }

     /* clear the structure */
     EAS_HWMemSet(pChorusData, 0, sizeof(S_CHORUS_OBJECT));

     ChorusReadInPresets(pChorusData);

     /* set some default values */
     pChorusData->bypass =       EAS_CHORUS_BYPASS_DEFAULT;
     pChorusData->preset =       EAS_CHORUS_PRESET_DEFAULT;
     pChorusData->m_nLevel =     EAS_CHORUS_LEVEL_DEFAULT;
     pChorusData->m_nRate =      EAS_CHORUS_RATE_DEFAULT;
     pChorusData->m_nDepth =     EAS_CHORUS_DEPTH_DEFAULT;

     //chorus rate and depth need some massaging from preset value (which is sample rate independent)

     //convert rate from steps of .05 Hz to value which can be used as phase increment,
     //with current CHORUS_SHAPE_SIZE and rate limits, this fits into 16 bits
     //want to compute ((shapeSize * 65536) * (storedRate/20))/sampleRate;
     //computing it as below allows rate steps to be evenly spaced
     //uses 32 bit divide, but only once when new value is selected
     pChorusData->m_nRate = (EAS_I16)
         ((((EAS_I32)CHORUS_SHAPE_SIZE<<16)/(20*(EAS_I32)_OUTPUT_SAMPLE_RATE)) * pChorusData->m_nRate);

     //convert depth from steps of .05 ms, to samples, with 16 bit whole part, discard fraction
     //want to compute ((depth * sampleRate)/20000)
     //use the following approximation since 105/32 is roughly 65536/20000
     /*lint -e{704} use shift for performance */
     pChorusData->m_nDepth = (EAS_I16)
         (((((EAS_I32)pChorusData->m_nDepth * _OUTPUT_SAMPLE_RATE)>>5) * 105) >> 16);

     pChorusData->m_nLevel = pChorusData->m_nLevel;

     //zero delay memory for chorus
     for (index = CHORUS_L_SIZE - 1; index >= 0; index--)
     {
         pChorusData->chorusDelayL[index] = 0;
     }
     for (index = CHORUS_R_SIZE - 1; index >= 0; index--)
     {
         pChorusData->chorusDelayR[index] = 0;
     }

     //init delay line index, these are used to implement circular delay buffer
     pChorusData->chorusIndexL = 0;
     pChorusData->chorusIndexR = 0;

     //init LFO phase
     //16 bit whole part, 16 bit fraction
     pChorusData->lfoLPhase = 0;
     pChorusData->lfoRPhase = (CHORUS_SHAPE_SIZE << 16) >> 2; // 1/4 of total, i.e. 90 degrees out of phase;

     //init chorus delay position
     //right now chorus delay is a compile-time value, as is sample rate
     pChorusData->chorusTapPosition = (EAS_I16)((CHORUS_DELAY_MS * _OUTPUT_SAMPLE_RATE)/1000);

     //now copy from the new preset into Chorus
     pPreset = &pChorusData->m_sPreset.m_sPreset[pChorusData->m_nNextChorus];

     pChorusData->m_nLevel = pPreset->m_nLevel;
     pChorusData->m_nRate =  pPreset->m_nRate;
     pChorusData->m_nDepth = pPreset->m_nDepth;

     pChorusData->m_nRate = (EAS_I16)
         ((((EAS_I32)CHORUS_SHAPE_SIZE<<16)/(20*(EAS_I32)_OUTPUT_SAMPLE_RATE)) * pChorusData->m_nRate);

     /*lint -e{704} use shift for performance */
     pChorusData->m_nDepth = (EAS_I16)
         (((((EAS_I32)pChorusData->m_nDepth * _OUTPUT_SAMPLE_RATE)>>5) * 105) >> 16);

     *pInstData = pChorusData;

     return EAS_SUCCESS;
 } /* end ChorusInit */

 /*----------------------------------------------------------------------------
  * WeightedTap()
  *----------------------------------------------------------------------------
  * Purpose: Does fractional array look-up using linear interpolation
  *
  * first convert indexDesired to actual desired index by taking into account indexReference
  * then do linear interpolation between two actual samples using fractional part
  *
  * Inputs:
  * array: pointer to array of signed 16 bit values, typically either PCM data or control data
  * indexReference: the circular buffer relative offset
  * indexDesired: the fractional index we are looking up (16 bits index + 16 bits fraction)
  * indexLimit: the total size of the array, used to compute buffer wrap
  *
  * Outputs:
  * Value from the input array, linearly interpolated between two actual data values
  *
  *----------------------------------------------------------------------------
 */
 static EAS_I16 WeightedTap(const EAS_I16 *array, EAS_I16 indexReference, EAS_I32 indexDesired, EAS_I16 indexLimit)
 {
     EAS_I16 index;
     EAS_I16 fraction;
     EAS_I16 val1;
     EAS_I16 val2;

     //separate indexDesired into whole and fractional parts
     /*lint -e{704} use shift for performance */
     index = (EAS_I16)(indexDesired >> 16);
     /*lint -e{704} use shift for performance */
     fraction = (EAS_I16)((indexDesired>>1) & 0x07FFF); //just use 15 bits of fractional part

     //adjust whole part by indexReference
     index = indexReference - index;
     //make sure we stay within array bounds, this implements circular buffer
     while (index < 0)
     {
         index += indexLimit;
     }

     //get two adjacent values from the array
     val1 = array[index];

     //handle special case when index == 0, else typical case
     if (index == 0)
     {
         val2 = array[indexLimit-1]; //get last value from array
     }
     else
     {
         val2 = array[index-1]; //get previous value from array
     }

     //compute linear interpolation as (val1 + ((val2-val1)*fraction))
     return(val1 + (EAS_I16)MULT_EG1_EG1(val2-val1,fraction));
 }

 /*----------------------------------------------------------------------------
  * ChorusProcess()
  *----------------------------------------------------------------------------
  * Purpose: compute the chorus on the input buffer, and mix into output buffer
  *
  *
  * Inputs:
  * src: pointer to input buffer of PCM values to be processed
  * dst: pointer to output buffer of PCM values we are to sume the result with
  * bufSize: the number of sample frames (i.e. stereo samples) in the buffer
  *
  * Outputs:
  * None
  *
  *----------------------------------------------------------------------------
 */
 //compute the chorus, and mix into output buffer
 static void ChorusProcess (EAS_VOID_PTR pInstData, EAS_PCM *pSrc, EAS_PCM *pDst, EAS_I32 numSamples)
 {
     EAS_I32 ix;
     EAS_I32 nChannelNumber;
     EAS_I16 lfoValueLeft;
     EAS_I16 lfoValueRight;
     EAS_I32 positionOffsetL;
     EAS_I32 positionOffsetR;
     EAS_PCM tapL;
     EAS_PCM tapR;
     EAS_I32 tempValue;
     EAS_PCM nInputSample;
     EAS_I32 nOutputSample;
     EAS_PCM *pIn;
     EAS_PCM *pOut;

     S_CHORUS_OBJECT *pChorusData;

     pChorusData = (S_CHORUS_OBJECT*) pInstData;

     //if the chorus is disabled or turned all the way down
     if (pChorusData->bypass == EAS_TRUE || pChorusData->m_nLevel == 0)
     {
         if (pSrc != pDst)
             EAS_HWMemCpy(pSrc, pDst, numSamples * NUM_OUTPUT_CHANNELS * (EAS_I32) sizeof(EAS_PCM));
         return;
     }

     if (pChorusData->m_nNextChorus != pChorusData->m_nCurrentChorus)
     {
         ChorusUpdate(pChorusData);
     }

     for (nChannelNumber = 0; nChannelNumber < NUM_OUTPUT_CHANNELS; nChannelNumber++)
     {

         pIn = pSrc + nChannelNumber;
         pOut = pDst + nChannelNumber;

         if(nChannelNumber==0)
         {
             for (ix = 0; ix < numSamples; ix++)
             {
                 nInputSample = *pIn;
                 pIn += NUM_OUTPUT_CHANNELS;

                 //feed input into chorus delay line
                 pChorusData->chorusDelayL[pChorusData->chorusIndexL] = nInputSample;

                 //compute chorus lfo value using phase as fractional index into chorus shape table
                 //resulting value is between -1.0 and 1.0, expressed as signed 16 bit number
                 lfoValueLeft = WeightedTap(EAS_chorusShape, 0, pChorusData->lfoLPhase, CHORUS_SHAPE_SIZE);

                 //scale chorus depth by lfo value to get relative fractional sample index
                 //index is expressed as 32 bit number with 16 bit fractional part
                 /*lint -e{703} use shift for performance */
                 positionOffsetL = pChorusData->m_nDepth * (((EAS_I32)lfoValueLeft) << 1);

                 //add fixed chorus delay to get actual fractional sample index
                 positionOffsetL += ((EAS_I32)pChorusData->chorusTapPosition) << 16;

                 //get tap value from chorus delay using fractional sample index
                 tapL = WeightedTap(pChorusData->chorusDelayL, pChorusData->chorusIndexL, positionOffsetL, CHORUS_L_SIZE);

                 //scale by chorus level, then sum with input buffer contents and saturate
                 tempValue = MULT_EG1_EG1(tapL, pChorusData->m_nLevel);
                 nOutputSample = SATURATE(tempValue + nInputSample);

                 *pOut = (EAS_I16)SATURATE(nOutputSample);
                 pOut += NUM_OUTPUT_CHANNELS;


                 //increment chorus delay index and make it wrap as needed
                 //this implements circular buffer
                 if ((pChorusData->chorusIndexL+=1) >= CHORUS_L_SIZE)
                     pChorusData->chorusIndexL = 0;

                 //increment fractional lfo phase, and make it wrap as needed
                 pChorusData->lfoLPhase += pChorusData->m_nRate;
                 while (pChorusData->lfoLPhase >= (CHORUS_SHAPE_SIZE<<16))
                 {
                     pChorusData->lfoLPhase -= (CHORUS_SHAPE_SIZE<<16);
                 }
             }
         }
         else
         {
             for (ix = 0; ix < numSamples; ix++)
             {
                 nInputSample = *pIn;
                 pIn += NUM_OUTPUT_CHANNELS;

                 //feed input into chorus delay line
                 pChorusData->chorusDelayR[pChorusData->chorusIndexR] = nInputSample;

                 //compute chorus lfo value using phase as fractional index into chorus shape table
                 //resulting value is between -1.0 and 1.0, expressed as signed 16 bit number
                 lfoValueRight = WeightedTap(EAS_chorusShape, 0, pChorusData->lfoRPhase, CHORUS_SHAPE_SIZE);

                 //scale chorus depth by lfo value to get relative fractional sample index
                 //index is expressed as 32 bit number with 16 bit fractional part
                 /*lint -e{703} use shift for performance */
                 positionOffsetR = pChorusData->m_nDepth * (((EAS_I32)lfoValueRight) << 1);

                 //add fixed chorus delay to get actual fractional sample index
                 positionOffsetR += ((EAS_I32)pChorusData->chorusTapPosition) << 16;

                 //get tap value from chorus delay using fractional sample index
                 tapR = WeightedTap(pChorusData->chorusDelayR, pChorusData->chorusIndexR, positionOffsetR, CHORUS_R_SIZE);

                 //scale by chorus level, then sum with output buffer contents and saturate
                 tempValue = MULT_EG1_EG1(tapR, pChorusData->m_nLevel);
                 nOutputSample = SATURATE(tempValue + nInputSample);

                 *pOut = (EAS_I16)SATURATE(nOutputSample);
                 pOut += NUM_OUTPUT_CHANNELS;

                 //increment chorus delay index and make it wrap as needed
                 //this implements circular buffer
                 if ((pChorusData->chorusIndexR+=1) >= CHORUS_R_SIZE)
                     pChorusData->chorusIndexR = 0;

                 //increment fractional lfo phase, and make it wrap as needed
                 pChorusData->lfoRPhase += pChorusData->m_nRate;
                 while (pChorusData->lfoRPhase >= (CHORUS_SHAPE_SIZE<<16))
                 {
                     pChorusData->lfoRPhase -= (CHORUS_SHAPE_SIZE<<16);
                 }
             }
         }

     }
 }  /* end ChorusProcess */


 /*----------------------------------------------------------------------------
  * ChorusShutdown()
  *----------------------------------------------------------------------------
  * Purpose:
  * Initializes the Chorus effect.
  *
  * Inputs:
  * pInstData        - handle to instance data
  *
  * Outputs:
  *
  *
  * Side Effects:
  *
  *----------------------------------------------------------------------------
 */
 static EAS_RESULT ChorusShutdown (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR pInstData)
 {
     /* check Configuration Module for static memory allocation */
     if (!pEASData->staticMemoryModel)
         EAS_HWFree(pEASData->hwInstData, pInstData);
     return EAS_SUCCESS;
 } /* end ChorusShutdown */

 /*----------------------------------------------------------------------------
  * ChorusGetParam()
  *----------------------------------------------------------------------------
  * Purpose:
  * Get a Chorus parameter
  *
  * Inputs:
  * pInstData        - handle to instance data
  * param            - parameter index
  * *pValue          - pointer to variable to hold retrieved value
  *
  * Outputs:
  *
  *
  * Side Effects:
  *
  *----------------------------------------------------------------------------
 */
 static EAS_RESULT ChorusGetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 *pValue)
 {
     S_CHORUS_OBJECT *p;

     p = (S_CHORUS_OBJECT*) pInstData;

     switch (param)
     {
         case EAS_PARAM_CHORUS_BYPASS:
             *pValue = (EAS_I32) p->bypass;
             break;
         case EAS_PARAM_CHORUS_PRESET:
             *pValue = (EAS_I8) p->m_nCurrentChorus;
             break;
         case EAS_PARAM_CHORUS_RATE:
             *pValue = (EAS_I32) p->m_nRate;
             break;
         case EAS_PARAM_CHORUS_DEPTH:
             *pValue = (EAS_I32) p->m_nDepth;
             break;
         case EAS_PARAM_CHORUS_LEVEL:
             *pValue = (EAS_I32) p->m_nLevel;
             break;
         default:
             return EAS_ERROR_INVALID_PARAMETER;
     }
     return EAS_SUCCESS;
 } /* end ChorusGetParam */


 /*----------------------------------------------------------------------------
  * ChorusSetParam()
  *----------------------------------------------------------------------------
  * Purpose:
  * Set a Chorus parameter
  *
  * Inputs:
  * pInstData        - handle to instance data
  * param            - parameter index
  * *pValue          - new paramter value
  *
  * Outputs:
  *
  *
  * Side Effects:
  *
  *----------------------------------------------------------------------------
 */
 static EAS_RESULT ChorusSetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 value)
 {
     S_CHORUS_OBJECT *p;

     p = (S_CHORUS_OBJECT*) pInstData;

     switch (param)
     {
         case EAS_PARAM_CHORUS_BYPASS:
             p->bypass = (EAS_BOOL) value;
             break;
         case EAS_PARAM_CHORUS_PRESET:
             if(value!=EAS_PARAM_CHORUS_PRESET1 && value!=EAS_PARAM_CHORUS_PRESET2 &&
                 value!=EAS_PARAM_CHORUS_PRESET3 && value!=EAS_PARAM_CHORUS_PRESET4)
                 return EAS_ERROR_INVALID_PARAMETER;
             p->m_nNextChorus = (EAS_I8)value;
             break;
         case EAS_PARAM_CHORUS_RATE:
             if(value<EAS_CHORUS_RATE_MIN || value>EAS_CHORUS_RATE_MAX)
                 return EAS_ERROR_INVALID_PARAMETER;
             p->m_nRate = (EAS_I16) value;
             break;
         case EAS_PARAM_CHORUS_DEPTH:
             if(value<EAS_CHORUS_DEPTH_MIN || value>EAS_CHORUS_DEPTH_MAX)
                 return EAS_ERROR_INVALID_PARAMETER;
             p->m_nDepth = (EAS_I16) value;
             break;
         case EAS_PARAM_CHORUS_LEVEL:
             if(value<EAS_CHORUS_LEVEL_MIN || value>EAS_CHORUS_LEVEL_MAX)
                 return EAS_ERROR_INVALID_PARAMETER;
             p->m_nLevel = (EAS_I16) value;
             break;

         default:
             return EAS_ERROR_INVALID_PARAMETER;
     }
     return EAS_SUCCESS;
 } /* end ChorusSetParam */


 /*----------------------------------------------------------------------------
  * ChorusReadInPresets()
  *----------------------------------------------------------------------------
  * Purpose: sets global Chorus preset bank to defaults
  *
  * Inputs:
  *
  * Outputs:
  *
  *----------------------------------------------------------------------------
 */
 static EAS_RESULT ChorusReadInPresets(S_CHORUS_OBJECT *pChorusData)
 {

     int preset = 0;
     int defaultPreset = 0;

     //now init any remaining presets to defaults
     for (defaultPreset = preset; defaultPreset < CHORUS_MAX_TYPE; defaultPreset++)
     {
         S_CHORUS_PRESET *pPreset = &pChorusData->m_sPreset.m_sPreset[defaultPreset];
         if (defaultPreset == 0 || defaultPreset > CHORUS_MAX_TYPE-1)
         {
             pPreset->m_nDepth = 39;
             pPreset->m_nRate = 30;
             pPreset->m_nLevel = 32767;
         }
         else if (defaultPreset == 1)
         {
             pPreset->m_nDepth = 21;
             pPreset->m_nRate = 45;
             pPreset->m_nLevel = 25000;
         }
         else if (defaultPreset == 2)
         {
             pPreset->m_nDepth = 53;
             pPreset->m_nRate = 25;
             pPreset->m_nLevel = 32000;
         }
         else if (defaultPreset == 3)
         {
             pPreset->m_nDepth = 32;
             pPreset->m_nRate = 37;
             pPreset->m_nLevel = 29000;
         }
     }

     return EAS_SUCCESS;
 }


 /*----------------------------------------------------------------------------
  * ChorusUpdate
  *----------------------------------------------------------------------------
  * Purpose:
  * Update the Chorus preset parameters as required
  *
  * Inputs:
  *
  * Outputs:
  *
  *
  * Side Effects:
  * - chorus paramters will be changed
  * - m_nCurrentRoom := m_nNextRoom
  *----------------------------------------------------------------------------
 */
 static EAS_RESULT ChorusUpdate(S_CHORUS_OBJECT *pChorusData)
 {
     S_CHORUS_PRESET *pPreset = &pChorusData->m_sPreset.m_sPreset[pChorusData->m_nNextChorus];

     pChorusData->m_nLevel = pPreset->m_nLevel;
     pChorusData->m_nRate =  pPreset->m_nRate;
     pChorusData->m_nDepth = pPreset->m_nDepth;

     pChorusData->m_nRate = (EAS_I16)
         ((((EAS_I32)CHORUS_SHAPE_SIZE<<16)/(20*(EAS_I32)_OUTPUT_SAMPLE_RATE)) * pChorusData->m_nRate);

     /*lint -e{704} use shift for performance */
     pChorusData->m_nDepth = (EAS_I16)
         (((((EAS_I32)pChorusData->m_nDepth * _OUTPUT_SAMPLE_RATE)>>5) * 105) >> 16);

     pChorusData->m_nCurrentChorus = pChorusData->m_nNextChorus;

     return EAS_SUCCESS;

 }   /* end ChorusUpdate */
	/*----------------------------------------------------------------------------
	*
	* File:
	* eas_chorus.c
	*
	* Contents and purpose:
	* Contains the implementation of the Chorus effect.
	*
	*
	* Copyright Sonic Network Inc. 2006

	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	*----------------------------------------------------------------------------
	* Revision Control:
	* $Revision: 499 $
	* $Date: 2006-12-11 16:07:20 -0800 (Mon, 11 Dec 2006) $
	*----------------------------------------------------------------------------
	*/

	#include "eas_data.h"
	#include "eas_effects.h"
	#include "eas_math.h"
	#include "eas_chorusdata.h"
	#include "eas_chorus.h"
	#include "eas_config.h"
	#include "eas_host.h"
	#include "eas_report.h"

	/* prototypes for effects interface */
	static EAS_RESULT ChorusInit (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR *pInstData);
	static void ChorusProcess (EAS_VOID_PTR pInstData, EAS_PCM pSrc, EAS_PCM pDst, EAS_I32 numSamples);
	static EAS_RESULT ChorusShutdown (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR pInstData);
	static EAS_RESULT ChorusGetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 *pValue);
	static EAS_RESULT ChorusSetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 value);

	/* common effects interface for configuration module */
	const S_EFFECTS_INTERFACE EAS_Chorus =
	{
	ChorusInit,
	ChorusProcess,
	ChorusShutdown,
	ChorusGetParam,
	ChorusSetParam
	};



	//LFO shape table used by the chorus, larger table would sound better
	//this is a sine wave, where 32767 = 1.0
	static const EAS_I16 EAS_chorusShape[CHORUS_SHAPE_SIZE] = {
	0, 1608, 3212, 4808, 6393, 7962, 9512, 11309, 12539, 14010, 15446, 16846, 18204, 19519, 20787, 22005, 23170,
	24279, 25329, 26319, 27245, 28105, 28898, 29621, 30273, 30852, 31356, 31785, 32137, 32412, 32609, 32728,
	32767, 32728, 32609, 32412, 32137, 31785, 31356, 30852, 30273, 29621, 28898, 28105, 27245, 26319, 25329,
	24279, 23170, 22005, 20787, 19519, 18204, 16846, 15446, 14010, 12539, 11039, 9512, 7962, 6393, 4808, 3212,
	1608, 0, -1608, -3212, -4808, -6393, -7962, -9512, -11309, -12539, -14010, -15446, -16846, -18204, -19519,
	-20787, -22005, -23170, -24279, -25329, -26319, -27245, -28105, -28898, -29621, -30273, -30852, -31356, -31785,
	-32137, -32412, -32609, -32728, -32767, -32728, -32609, -32412, -32137, -31785, -31356, -30852, -30273, -29621,
	-28898, -28105, -27245, -26319, -25329, -24279, -23170, -22005, -20787, -19519, -18204, -16846, -15446, -14010,
	-12539, -11039, -9512, -7962, -6393, -4808, -3212, -1608
	};

	/*----------------------------------------------------------------------------
	* InitializeChorus()
	*----------------------------------------------------------------------------
	* Purpose: Initializes chorus parameters
	*
	*
	* Inputs:
	*
	* Outputs:
	*
	*----------------------------------------------------------------------------
	*/
	static EAS_RESULT ChorusInit (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR *pInstData)
	{
	S_CHORUS_OBJECT *pChorusData;
	S_CHORUS_PRESET *pPreset;
	EAS_I32 index;

	/* check Configuration Module for data allocation */
	if (pEASData->staticMemoryModel)
	pChorusData = EAS_CMEnumFXData(EAS_MODULE_CHORUS);

	/* allocate dynamic memory */
	else
	pChorusData = EAS_HWMalloc(pEASData->hwInstData, sizeof(S_CHORUS_OBJECT));

	if (pChorusData == NULL)
	{
	{ /* dpp: EAS_ReportEx(_EAS_SEVERITY_FATAL, "Failed to allocate Chorus memory\n"); */ }
	return EAS_ERROR_MALLOC_FAILED;
	}

	/* clear the structure */
	EAS_HWMemSet(pChorusData, 0, sizeof(S_CHORUS_OBJECT));

	ChorusReadInPresets(pChorusData);

	/* set some default values */
	pChorusData->bypass = EAS_CHORUS_BYPASS_DEFAULT;
	pChorusData->preset = EAS_CHORUS_PRESET_DEFAULT;
	pChorusData->m_nLevel = EAS_CHORUS_LEVEL_DEFAULT;
	pChorusData->m_nRate = EAS_CHORUS_RATE_DEFAULT;
	pChorusData->m_nDepth = EAS_CHORUS_DEPTH_DEFAULT;

	//chorus rate and depth need some massaging from preset value (which is sample rate independent)

	//convert rate from steps of .05 Hz to value which can be used as phase increment,
	//with current CHORUS_SHAPE_SIZE and rate limits, this fits into 16 bits
	//want to compute ((shapeSize * 65536) * (storedRate/20))/sampleRate;
	//computing it as below allows rate steps to be evenly spaced
	//uses 32 bit divide, but only once when new value is selected
	pChorusData->m_nRate = (EAS_I16)
	((((EAS_I32)CHORUS_SHAPE_SIZE<<16)/(20(EAS_I32)_OUTPUT_SAMPLE_RATE)) pChorusData->m_nRate);

	//convert depth from steps of .05 ms, to samples, with 16 bit whole part, discard fraction
	//want to compute ((depth * sampleRate)/20000)
	//use the following approximation since 105/32 is roughly 65536/20000
	/lint -e{704} use shift for performance /
	pChorusData->m_nDepth = (EAS_I16)
	(((((EAS_I32)pChorusData->m_nDepth * _OUTPUT_SAMPLE_RATE)>>5) * 105) >> 16);

	pChorusData->m_nLevel = pChorusData->m_nLevel;

	//zero delay memory for chorus
	for (index = CHORUS_L_SIZE - 1; index >= 0; index--)
	{
	pChorusData->chorusDelayL[index] = 0;
	}
	for (index = CHORUS_R_SIZE - 1; index >= 0; index--)
	{
	pChorusData->chorusDelayR[index] = 0;
	}

	//init delay line index, these are used to implement circular delay buffer
	pChorusData->chorusIndexL = 0;
	pChorusData->chorusIndexR = 0;

	//init LFO phase
	//16 bit whole part, 16 bit fraction
	pChorusData->lfoLPhase = 0;
	pChorusData->lfoRPhase = (CHORUS_SHAPE_SIZE << 16) >> 2; // 1/4 of total, i.e. 90 degrees out of phase;

	//init chorus delay position
	//right now chorus delay is a compile-time value, as is sample rate
	pChorusData->chorusTapPosition = (EAS_I16)((CHORUS_DELAY_MS * _OUTPUT_SAMPLE_RATE)/1000);

	//now copy from the new preset into Chorus
	pPreset = &pChorusData->m_sPreset.m_sPreset[pChorusData->m_nNextChorus];

	pChorusData->m_nLevel = pPreset->m_nLevel;
	pChorusData->m_nRate = pPreset->m_nRate;
	pChorusData->m_nDepth = pPreset->m_nDepth;

	pChorusData->m_nRate = (EAS_I16)
	((((EAS_I32)CHORUS_SHAPE_SIZE<<16)/(20(EAS_I32)_OUTPUT_SAMPLE_RATE)) pChorusData->m_nRate);

	/lint -e{704} use shift for performance /
	pChorusData->m_nDepth = (EAS_I16)
	(((((EAS_I32)pChorusData->m_nDepth * _OUTPUT_SAMPLE_RATE)>>5) * 105) >> 16);

	*pInstData = pChorusData;

	return EAS_SUCCESS;
	} /* end ChorusInit */

	/*----------------------------------------------------------------------------
	* WeightedTap()
	*----------------------------------------------------------------------------
	* Purpose: Does fractional array look-up using linear interpolation
	*
	* first convert indexDesired to actual desired index by taking into account indexReference
	* then do linear interpolation between two actual samples using fractional part
	*
	* Inputs:
	* array: pointer to array of signed 16 bit values, typically either PCM data or control data
	* indexReference: the circular buffer relative offset
	* indexDesired: the fractional index we are looking up (16 bits index + 16 bits fraction)
	* indexLimit: the total size of the array, used to compute buffer wrap
	*
	* Outputs:
	* Value from the input array, linearly interpolated between two actual data values
	*
	*----------------------------------------------------------------------------
	*/
	static EAS_I16 WeightedTap(const EAS_I16 *array, EAS_I16 indexReference, EAS_I32 indexDesired, EAS_I16 indexLimit)
	{
	EAS_I16 index;
	EAS_I16 fraction;
	EAS_I16 val1;
	EAS_I16 val2;

	//separate indexDesired into whole and fractional parts
	/lint -e{704} use shift for performance /
	index = (EAS_I16)(indexDesired >> 16);
	/lint -e{704} use shift for performance /
	fraction = (EAS_I16)((indexDesired>>1) & 0x07FFF); //just use 15 bits of fractional part

	//adjust whole part by indexReference
	index = indexReference - index;
	//make sure we stay within array bounds, this implements circular buffer
	while (index < 0)
	{
	index += indexLimit;
	}

	//get two adjacent values from the array
	val1 = array[index];

	//handle special case when index == 0, else typical case
	if (index == 0)
	{
	val2 = array[indexLimit-1]; //get last value from array
	}
	else
	{
	val2 = array[index-1]; //get previous value from array
	}

	//compute linear interpolation as (val1 + ((val2-val1)*fraction))
	return(val1 + (EAS_I16)MULT_EG1_EG1(val2-val1,fraction));
	}

	/*----------------------------------------------------------------------------
	* ChorusProcess()
	*----------------------------------------------------------------------------
	* Purpose: compute the chorus on the input buffer, and mix into output buffer
	*
	*
	* Inputs:
	* src: pointer to input buffer of PCM values to be processed
	* dst: pointer to output buffer of PCM values we are to sume the result with
	* bufSize: the number of sample frames (i.e. stereo samples) in the buffer
	*
	* Outputs:
	* None
	*
	*----------------------------------------------------------------------------
	*/
	//compute the chorus, and mix into output buffer
	static void ChorusProcess (EAS_VOID_PTR pInstData, EAS_PCM pSrc, EAS_PCM pDst, EAS_I32 numSamples)
	{
	EAS_I32 ix;
	EAS_I32 nChannelNumber;
	EAS_I16 lfoValueLeft;
	EAS_I16 lfoValueRight;
	EAS_I32 positionOffsetL;
	EAS_I32 positionOffsetR;
	EAS_PCM tapL;
	EAS_PCM tapR;
	EAS_I32 tempValue;
	EAS_PCM nInputSample;
	EAS_I32 nOutputSample;
	EAS_PCM *pIn;
	EAS_PCM *pOut;

	S_CHORUS_OBJECT *pChorusData;

	pChorusData = (S_CHORUS_OBJECT*) pInstData;

	//if the chorus is disabled or turned all the way down
	if (pChorusData->bypass == EAS_TRUE \|\| pChorusData->m_nLevel == 0)
	{
	if (pSrc != pDst)
	EAS_HWMemCpy(pSrc, pDst, numSamples * NUM_OUTPUT_CHANNELS * (EAS_I32) sizeof(EAS_PCM));
	return;
	}

	if (pChorusData->m_nNextChorus != pChorusData->m_nCurrentChorus)
	{
	ChorusUpdate(pChorusData);
	}

	for (nChannelNumber = 0; nChannelNumber < NUM_OUTPUT_CHANNELS; nChannelNumber++)
	{

	pIn = pSrc + nChannelNumber;
	pOut = pDst + nChannelNumber;

	if(nChannelNumber==0)
	{
	for (ix = 0; ix < numSamples; ix++)
	{
	nInputSample = *pIn;
	pIn += NUM_OUTPUT_CHANNELS;

	//feed input into chorus delay line
	pChorusData->chorusDelayL[pChorusData->chorusIndexL] = nInputSample;

	//compute chorus lfo value using phase as fractional index into chorus shape table
	//resulting value is between -1.0 and 1.0, expressed as signed 16 bit number
	lfoValueLeft = WeightedTap(EAS_chorusShape, 0, pChorusData->lfoLPhase, CHORUS_SHAPE_SIZE);

	//scale chorus depth by lfo value to get relative fractional sample index
	//index is expressed as 32 bit number with 16 bit fractional part
	/lint -e{703} use shift for performance /
	positionOffsetL = pChorusData->m_nDepth * (((EAS_I32)lfoValueLeft) << 1);

	//add fixed chorus delay to get actual fractional sample index
	positionOffsetL += ((EAS_I32)pChorusData->chorusTapPosition) << 16;

	//get tap value from chorus delay using fractional sample index
	tapL = WeightedTap(pChorusData->chorusDelayL, pChorusData->chorusIndexL, positionOffsetL, CHORUS_L_SIZE);

	//scale by chorus level, then sum with input buffer contents and saturate
	tempValue = MULT_EG1_EG1(tapL, pChorusData->m_nLevel);
	nOutputSample = SATURATE(tempValue + nInputSample);

	*pOut = (EAS_I16)SATURATE(nOutputSample);
	pOut += NUM_OUTPUT_CHANNELS;


	//increment chorus delay index and make it wrap as needed
	//this implements circular buffer
	if ((pChorusData->chorusIndexL+=1) >= CHORUS_L_SIZE)
	pChorusData->chorusIndexL = 0;

	//increment fractional lfo phase, and make it wrap as needed
	pChorusData->lfoLPhase += pChorusData->m_nRate;
	while (pChorusData->lfoLPhase >= (CHORUS_SHAPE_SIZE<<16))
	{
	pChorusData->lfoLPhase -= (CHORUS_SHAPE_SIZE<<16);
	}
	}
	}
	else
	{
	for (ix = 0; ix < numSamples; ix++)
	{
	nInputSample = *pIn;
	pIn += NUM_OUTPUT_CHANNELS;

	//feed input into chorus delay line
	pChorusData->chorusDelayR[pChorusData->chorusIndexR] = nInputSample;

	//compute chorus lfo value using phase as fractional index into chorus shape table
	//resulting value is between -1.0 and 1.0, expressed as signed 16 bit number
	lfoValueRight = WeightedTap(EAS_chorusShape, 0, pChorusData->lfoRPhase, CHORUS_SHAPE_SIZE);

	//scale chorus depth by lfo value to get relative fractional sample index
	//index is expressed as 32 bit number with 16 bit fractional part
	/lint -e{703} use shift for performance /
	positionOffsetR = pChorusData->m_nDepth * (((EAS_I32)lfoValueRight) << 1);

	//add fixed chorus delay to get actual fractional sample index
	positionOffsetR += ((EAS_I32)pChorusData->chorusTapPosition) << 16;

	//get tap value from chorus delay using fractional sample index
	tapR = WeightedTap(pChorusData->chorusDelayR, pChorusData->chorusIndexR, positionOffsetR, CHORUS_R_SIZE);

	//scale by chorus level, then sum with output buffer contents and saturate
	tempValue = MULT_EG1_EG1(tapR, pChorusData->m_nLevel);
	nOutputSample = SATURATE(tempValue + nInputSample);

	*pOut = (EAS_I16)SATURATE(nOutputSample);
	pOut += NUM_OUTPUT_CHANNELS;

	//increment chorus delay index and make it wrap as needed
	//this implements circular buffer
	if ((pChorusData->chorusIndexR+=1) >= CHORUS_R_SIZE)
	pChorusData->chorusIndexR = 0;

	//increment fractional lfo phase, and make it wrap as needed
	pChorusData->lfoRPhase += pChorusData->m_nRate;
	while (pChorusData->lfoRPhase >= (CHORUS_SHAPE_SIZE<<16))
	{
	pChorusData->lfoRPhase -= (CHORUS_SHAPE_SIZE<<16);
	}
	}
	}

	}
	} /* end ChorusProcess */



	/*----------------------------------------------------------------------------
	* ChorusShutdown()
	*----------------------------------------------------------------------------
	* Purpose:
	* Initializes the Chorus effect.
	*
	* Inputs:
	* pInstData - handle to instance data
	*
	* Outputs:
	*
	*
	* Side Effects:
	*
	*----------------------------------------------------------------------------
	*/
	static EAS_RESULT ChorusShutdown (EAS_DATA_HANDLE pEASData, EAS_VOID_PTR pInstData)
	{
	/* check Configuration Module for static memory allocation */
	if (!pEASData->staticMemoryModel)
	EAS_HWFree(pEASData->hwInstData, pInstData);
	return EAS_SUCCESS;
	} /* end ChorusShutdown */

	/*----------------------------------------------------------------------------
	* ChorusGetParam()
	*----------------------------------------------------------------------------
	* Purpose:
	* Get a Chorus parameter
	*
	* Inputs:
	* pInstData - handle to instance data
	* param - parameter index
	* *pValue - pointer to variable to hold retrieved value
	*
	* Outputs:
	*
	*
	* Side Effects:
	*
	*----------------------------------------------------------------------------
	*/
	static EAS_RESULT ChorusGetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 *pValue)
	{
	S_CHORUS_OBJECT *p;

	p = (S_CHORUS_OBJECT*) pInstData;

	switch (param)
	{
	case EAS_PARAM_CHORUS_BYPASS:
	*pValue = (EAS_I32) p->bypass;
	break;
	case EAS_PARAM_CHORUS_PRESET:
	*pValue = (EAS_I8) p->m_nCurrentChorus;
	break;
	case EAS_PARAM_CHORUS_RATE:
	*pValue = (EAS_I32) p->m_nRate;
	break;
	case EAS_PARAM_CHORUS_DEPTH:
	*pValue = (EAS_I32) p->m_nDepth;
	break;
	case EAS_PARAM_CHORUS_LEVEL:
	*pValue = (EAS_I32) p->m_nLevel;
	break;
	default:
	return EAS_ERROR_INVALID_PARAMETER;
	}
	return EAS_SUCCESS;
	} /* end ChorusGetParam */


	/*----------------------------------------------------------------------------
	* ChorusSetParam()
	*----------------------------------------------------------------------------
	* Purpose:
	* Set a Chorus parameter
	*
	* Inputs:
	* pInstData - handle to instance data
	* param - parameter index
	* *pValue - new paramter value
	*
	* Outputs:
	*
	*
	* Side Effects:
	*
	*----------------------------------------------------------------------------
	*/
	static EAS_RESULT ChorusSetParam (EAS_VOID_PTR pInstData, EAS_I32 param, EAS_I32 value)
	{
	S_CHORUS_OBJECT *p;

	p = (S_CHORUS_OBJECT*) pInstData;

	switch (param)
	{
	case EAS_PARAM_CHORUS_BYPASS:
	p->bypass = (EAS_BOOL) value;
	break;
	case EAS_PARAM_CHORUS_PRESET:
	if(value!=EAS_PARAM_CHORUS_PRESET1 && value!=EAS_PARAM_CHORUS_PRESET2 &&
	value!=EAS_PARAM_CHORUS_PRESET3 && value!=EAS_PARAM_CHORUS_PRESET4)
	return EAS_ERROR_INVALID_PARAMETER;
	p->m_nNextChorus = (EAS_I8)value;
	break;
	case EAS_PARAM_CHORUS_RATE:
	if(value<EAS_CHORUS_RATE_MIN \|\| value>EAS_CHORUS_RATE_MAX)
	return EAS_ERROR_INVALID_PARAMETER;
	p->m_nRate = (EAS_I16) value;
	break;
	case EAS_PARAM_CHORUS_DEPTH:
	if(value<EAS_CHORUS_DEPTH_MIN \|\| value>EAS_CHORUS_DEPTH_MAX)
	return EAS_ERROR_INVALID_PARAMETER;
	p->m_nDepth = (EAS_I16) value;
	break;
	case EAS_PARAM_CHORUS_LEVEL:
	if(value<EAS_CHORUS_LEVEL_MIN \|\| value>EAS_CHORUS_LEVEL_MAX)
	return EAS_ERROR_INVALID_PARAMETER;
	p->m_nLevel = (EAS_I16) value;
	break;

	default:
	return EAS_ERROR_INVALID_PARAMETER;
	}
	return EAS_SUCCESS;
	} /* end ChorusSetParam */


	/*----------------------------------------------------------------------------
	* ChorusReadInPresets()
	*----------------------------------------------------------------------------
	* Purpose: sets global Chorus preset bank to defaults
	*
	* Inputs:
	*
	* Outputs:
	*
	*----------------------------------------------------------------------------
	*/
	static EAS_RESULT ChorusReadInPresets(S_CHORUS_OBJECT *pChorusData)
	{

	int preset = 0;
	int defaultPreset = 0;

	//now init any remaining presets to defaults
	for (defaultPreset = preset; defaultPreset < CHORUS_MAX_TYPE; defaultPreset++)
	{
	S_CHORUS_PRESET *pPreset = &pChorusData->m_sPreset.m_sPreset[defaultPreset];
	if (defaultPreset == 0 \|\| defaultPreset > CHORUS_MAX_TYPE-1)
	{
	pPreset->m_nDepth = 39;
	pPreset->m_nRate = 30;
	pPreset->m_nLevel = 32767;
	}
	else if (defaultPreset == 1)
	{
	pPreset->m_nDepth = 21;
	pPreset->m_nRate = 45;
	pPreset->m_nLevel = 25000;
	}
	else if (defaultPreset == 2)
	{
	pPreset->m_nDepth = 53;
	pPreset->m_nRate = 25;
	pPreset->m_nLevel = 32000;
	}
	else if (defaultPreset == 3)
	{
	pPreset->m_nDepth = 32;
	pPreset->m_nRate = 37;
	pPreset->m_nLevel = 29000;
	}
	}

	return EAS_SUCCESS;
	}


	/*----------------------------------------------------------------------------
	* ChorusUpdate
	*----------------------------------------------------------------------------
	* Purpose:
	* Update the Chorus preset parameters as required
	*
	* Inputs:
	*
	* Outputs:
	*
	*
	* Side Effects:
	* - chorus paramters will be changed
	* - m_nCurrentRoom := m_nNextRoom
	*----------------------------------------------------------------------------
	*/
	static EAS_RESULT ChorusUpdate(S_CHORUS_OBJECT *pChorusData)
	{
	S_CHORUS_PRESET *pPreset = &pChorusData->m_sPreset.m_sPreset[pChorusData->m_nNextChorus];

	pChorusData->m_nLevel = pPreset->m_nLevel;
	pChorusData->m_nRate = pPreset->m_nRate;
	pChorusData->m_nDepth = pPreset->m_nDepth;

	pChorusData->m_nRate = (EAS_I16)
	((((EAS_I32)CHORUS_SHAPE_SIZE<<16)/(20(EAS_I32)_OUTPUT_SAMPLE_RATE)) pChorusData->m_nRate);

	/lint -e{704} use shift for performance /
	pChorusData->m_nDepth = (EAS_I16)
	(((((EAS_I32)pChorusData->m_nDepth * _OUTPUT_SAMPLE_RATE)>>5) * 105) >> 16);

	pChorusData->m_nCurrentChorus = pChorusData->m_nNextChorus;

	return EAS_SUCCESS;

	} /* end ChorusUpdate */