/*
Copyright (c) 2016, Texas Instruments Incorporated - http://www.ti.com/
All rights reserved.

* Redistribution and use in source and binary forms, with or without 
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* Neither the name of Texas Instruments Incorporated nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER 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 OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

#include <string.h> // for memset()
#include <xdc/std.h>
#include <xdc/runtime/Log.h>
#include <ti/sysbios/hal/Cache.h>
#include <ti/uia/events/UIAEvt.h>
#include <ti/ipc/GateMP.h>

#include "common.h"
#include "paftyp.h"
#include "pafdec.h"
#include "aspDecOpCircBuf_master.h"

#define DEF_SOURCE_SEL          ( PAF_SOURCE_PCM ) // default source select
#define DEF_DEC_OP_FRAME_LEN    ( 256 )     // default decoder output frame length
#define DEF_STR_FRAME_LEN       ( 256 )     // default stream frame length

#define MAX_NUM_AF_PCM      ( 4 )
#define CB_INIT_RD_LAG_PCM  ( 2 ) // 0...3

#define MAX_NUM_AF_DDP      ( 2 )
#define CB_INIT_RD_LAG_DDP  ( 4 ) // 0...5

// Generate mute AF on circular buffer read
static Void cbReadAfMute(
    PAF_AudioFrame *pAfRd,      // audio frame into which to read
    Int16 strFrameLen           // stream frame length (output transaction size)
);


// Initialize circular buffer control
Int cbCtlInit(
    PAF_AST_DecOpCircBufCtl *pCbCtl,    // decoder output circular buffer control
    PAF_AST_DecOpCircBuf **pXDecOpCb    // address of decoder output circular buffer base pointer
)
{
    GateMP_Params gateParams;
    GateMP_Handle gateHandle;
    
    GateMP_Params_init(&gateParams);
    gateParams.localProtect = GateMP_LocalProtect_THREAD;
    gateParams.remoteProtect = GateMP_RemoteProtect_SYSTEM;
    gateParams.name = ASP_DECODE_CB_GATE_NAME;
    gateParams.regionId = ASP_DECODE_CB_GATE_REGION_ID;
    gateHandle = GateMP_create(&gateParams);
    if (gateHandle != NULL)
    {
        pCbCtl->gateHandle = gateHandle;
    }
    else
    {
        pCbCtl->gateHandle = NULL;
        return ASP_DECOP_CB_CTL_INIT_INV_GATE;
    }
    
    pCbCtl->pXDecOpCb = pXDecOpCb;
    
    return ASP_DECOP_CB_SOK;
    
}

// Initialize circular buffer
Int cbInit(
    PAF_AST_DecOpCircBuf *pCb
)
{
    PAF_AudioFrame *pAfCb;
    PAF_AudioData *pPcmBuf;
    UInt8 *pMetaBuf;
    Int8 n;
    Int8 i;

    // set source select
    pCb->sourceSel = DEF_SOURCE_SEL;

    // set input frame length
    pCb->decOpFrameLen = DEF_DEC_OP_FRAME_LEN;
    
    // set output frame length
    pCb->strFrameLen = DEF_STR_FRAME_LEN;
    
    // initialize circular buffer maximum number of audio frames
    pCb->maxNumAfCb = MAX_NUM_AF_PCM;
    pCb->afWrtIdx = CB_INIT_RD_LAG_PCM;
    pCb->afRdIdx = 0;
    pCb->pcmRdIdx = 0; // 2*256 in behind
    
    // initialize audio frames
    for (n=0; n<pCb->maxNumAfCb; n++)
    {
        pAfCb = &pCb->afCb[n];
        pAfCb->sampleDecode = PAF_SOURCE_PCM;
        PAF_PROCESS_ZERO(pAfCb->sampleProcess);
        pAfCb->sampleRate = PAF_SAMPLERATE_48000HZ;
        pAfCb->sampleCount = DEF_DEC_OP_FRAME_LEN;
        pAfCb->channelConfigurationRequest.full = 0;
        pAfCb->channelConfigurationRequest.part.sat = PAF_CC_SAT_SURROUND4;
        pAfCb->channelConfigurationRequest.part.sub = PAF_CC_SUB_ONE;
        pAfCb->channelConfigurationStream.full = 0;
        pAfCb->channelConfigurationStream.part.sat = PAF_CC_SAT_SURROUND4;
        pAfCb->channelConfigurationStream.part.sub = PAF_CC_SUB_ONE;
    }

    // initialize circular buffer current number of frames
    pCb->numAfCb = pCb->afWrtIdx - pCb->afRdIdx;
    
    // initialize audio frame PCM buffers
    pPcmBuf = pCb->pcmBuf;
    pMetaBuf = pCb->metaBuf; //QIN
    for (n=0; n<pCb->maxNumAfCb; n++)
    {
        pAfCb = &pCb->afCb[n];
        pAfCb->data.nChannels = ASP_DECOP_CB_MAX_NUM_PCM_CH;
        pAfCb->data.nSamples = DEF_DEC_OP_FRAME_LEN;
        for (i=0; i<ASP_DECOP_CB_MAX_NUM_PCM_CH; i++)
        {
            pAfCb->data.sample[i] = pPcmBuf;
            memset(pAfCb->data.sample[i], DEF_DEC_OP_FRAME_LEN, 0);
            pPcmBuf += DEF_DEC_OP_FRAME_LEN;
            
            pAfCb->data.samsiz[i] = 0;
        }
        
        // Initialize metadata buffers //QIN
        for (i=0; i<PAF_MAX_NUM_PRIVATE_MD; i++)
        {
            pAfCb->pafPrivateMetadata[i].offset = 0; 
            pAfCb->pafPrivateMetadata[i].size   = 0; 
            pAfCb->pafPrivateMetadata[i].pMdBuf = pMetaBuf;
            pMetaBuf += PAF_MAX_PRIVATE_MD_SZ;
        }
    }
    
    // reset read/write flags
    pCb->writerActiveFlag = 0;
    pCb->readerActiveFlag = 0;
    pCb->emptyFlag = 0;
    
    // reset error counts
    pCb->errUndCnt = 0;
    pCb->errOvrCnt = 0;
    
    // (***) FL: revisit
    // Write back circular buffer configuration
    Cache_wb(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    // Write back AF circular buffer
    Cache_wb(pCb->afCb, pCb->maxNumAfCb*sizeof(PAF_AudioFrame), Cache_Type_ALLD, 0);
    // Write back PCM data
    for (n=0; n<pCb->maxNumAfCb; n++)
    {
        pAfCb = &pCb->afCb[n];
        Cache_wb(pAfCb->data.samsiz, ASP_DECOP_CB_MAX_NUM_PCM_CH*sizeof(PAF_AudioSize), Cache_Type_ALLD, 0);
        Cache_wb(pAfCb->data.sample, ASP_DECOP_CB_MAX_NUM_PCM_CH*sizeof(PAF_AudioData *), Cache_Type_ALLD, 0);
        for (i=0; i<ASP_DECOP_CB_MAX_NUM_PCM_CH; i++)
        {
            Cache_wb(pAfCb->data.sample[i], DEF_DEC_OP_FRAME_LEN*sizeof(PAF_AudioData), Cache_Type_ALLD, 0);
        }
        // FL: unnecessary since part of AF
        //for (i=0; i<PAF_MAX_NUM_PRIVATE_MD; i++)     // Write back metadata //QIN
        //{
        //    Cache_wb(&pAfCb->pafPrivateMetadata[i], sizeof(PAF_PrivateMetadata), Cache_Type_ALLD, 0);
        //}
    }
    Cache_wait();

    return ASP_DECOP_CB_SOK;
}

// Initialize circular buffer based on selected source
Int cbInitSourceSel(
    PAF_AST_DecOpCircBufCtl *pCbCtl,    // decoder output circular buffer control
    Int8 cbIdx,                         // decoder output circular buffer index
    Int8 sourceSelect,                  // source select (PCM, DDP, etc.)
    Int16 decOpFrameLen,                // decoder output frame length (PCM samples)
    Int16 strFrameLen,                  // stream frame length (PCM samples)
    Int8 resetRwFlags                   // whether to reset reader, writer, and empty flags
)
{
    IArg key;
    GateMP_Handle gateHandle;
    PAF_AST_DecOpCircBuf *pCb;
    PAF_AudioFrame *pAfCb;
    PAF_AudioData *pPcmBuf;
    UInt8 *pMetaBuf; //QIN
    Int8 n;
    Int8 i;

    // Get gate handle
    gateHandle = pCbCtl->gateHandle;
    // Enter gate
    key = GateMP_enter(gateHandle);

    // Get circular buffer base pointer
    pCb = &((*pCbCtl->pXDecOpCb)[cbIdx]);
    
    // Invalidate circular buffer configuration
    Cache_inv(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    Cache_wait();

    //Log_info1("cbInitSourceSel:afCb=0x%04x", (IArg)pCb->afCb); // FL: debug

    // set source select
    pCb->sourceSel = sourceSelect;

    // set input frame length
    pCb->decOpFrameLen = decOpFrameLen;
    
    // set output frame length
    pCb->strFrameLen = strFrameLen;
    
    // initialize circular buffer maximum number of audio frames
    if (sourceSelect == PAF_SOURCE_PCM)
    {
        pCb->maxNumAfCb = MAX_NUM_AF_PCM;
        pCb->afWrtIdx = CB_INIT_RD_LAG_PCM;
        pCb->afRdIdx = 0;
        pCb->pcmRdIdx = 0; // 2*256 in behind
        
        // initialize audio frames
        for (n=0; n<pCb->maxNumAfCb; n++)
        {
            pAfCb = &pCb->afCb[n];
            pAfCb->sampleDecode = PAF_SOURCE_PCM;
            PAF_PROCESS_ZERO(pAfCb->sampleProcess);
            pAfCb->sampleRate = PAF_SAMPLERATE_48000HZ;
            pAfCb->sampleCount = decOpFrameLen;
            pAfCb->channelConfigurationRequest.full = 0;
            pAfCb->channelConfigurationRequest.part.sat = PAF_CC_SAT_SURROUND4;
            pAfCb->channelConfigurationRequest.part.sub = PAF_CC_SUB_ONE;
            pAfCb->channelConfigurationStream.full = 0;
            pAfCb->channelConfigurationStream.part.sat = PAF_CC_SAT_SURROUND4;
            pAfCb->channelConfigurationStream.part.sub = PAF_CC_SUB_ONE;
        }
    }
    else if (sourceSelect == PAF_SOURCE_DDP)
    {
        pCb->maxNumAfCb = MAX_NUM_AF_DDP;
        pCb->afWrtIdx = 1;
        pCb->afRdIdx = 0;
        pCb->pcmRdIdx = decOpFrameLen - CB_INIT_RD_LAG_DDP*strFrameLen; // 4*256 behind
        
        // initialize audio frames
        for (n=0; n<pCb->maxNumAfCb; n++)
        {
            pAfCb = &pCb->afCb[n];
            pAfCb->sampleDecode = PAF_SOURCE_DDP;
            PAF_PROCESS_ZERO(pAfCb->sampleProcess);
            pAfCb->sampleRate = PAF_SAMPLERATE_48000HZ;
            pAfCb->sampleCount = decOpFrameLen;
            pAfCb->channelConfigurationRequest.full = 0;
            pAfCb->channelConfigurationRequest.part.sat = PAF_CC_SAT_SURROUND4;
            pAfCb->channelConfigurationRequest.part.sub = PAF_CC_SUB_ONE;
            pAfCb->channelConfigurationStream.full = 0;
            pAfCb->channelConfigurationStream.part.sat = PAF_CC_SAT_SURROUND4;
            pAfCb->channelConfigurationStream.part.sub = PAF_CC_SUB_ONE;
        }
    }
    else
    {
        // Leave the gate
        GateMP_leave(gateHandle, key);

        return ASP_DECOP_CB_INIT_INV_SOURCE_SEL;
    }

    // initialize circular buffer current number of frames
    pCb->numAfCb = pCb->afWrtIdx - pCb->afRdIdx;
    
    // initialize audio frame PCM buffers
    pPcmBuf = pCb->pcmBuf;
    pMetaBuf = pCb->metaBuf; //QIN
    for (n=0; n<pCb->maxNumAfCb; n++)
    {
        pAfCb = &pCb->afCb[n];
        pAfCb->data.nChannels = ASP_DECOP_CB_MAX_NUM_PCM_CH;
        pAfCb->data.nSamples = decOpFrameLen;
        for (i=0; i<ASP_DECOP_CB_MAX_NUM_PCM_CH; i++)
        {
            pAfCb->data.sample[i] = pPcmBuf;
            memset(pAfCb->data.sample[i], decOpFrameLen, 0);
            pPcmBuf += decOpFrameLen;
            
            pAfCb->data.samsiz[i] = 0;
        }
        
        // Initialize metadata buffers //QIN
        for (i=0; i<PAF_MAX_NUM_PRIVATE_MD; i++)
        {
            pAfCb->pafPrivateMetadata[i].offset = 0; 
            pAfCb->pafPrivateMetadata[i].size   = 0; 
            pAfCb->pafPrivateMetadata[i].pMdBuf = pMetaBuf;
            pMetaBuf += PAF_MAX_PRIVATE_MD_SZ;
        }
    }
    
    // reset read/write flags
    if (resetRwFlags)
    {
        pCb->writerActiveFlag = 0;
        pCb->readerActiveFlag = 0;
        pCb->emptyFlag = 0;
    }
    
    // reset error counts
    pCb->errUndCnt = 0;
    pCb->errOvrCnt = 0;
    
    // (***) FL: revisit
    // Write back circular buffer configuration
    Cache_wb(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    // Write back AF circular buffer
    Cache_wb(pCb->afCb, pCb->maxNumAfCb*sizeof(PAF_AudioFrame), Cache_Type_ALLD, 0);
    // Write back PCM data
    for (n=0; n<pCb->maxNumAfCb; n++)
    {
        pAfCb = &pCb->afCb[n];
        Cache_wb(pAfCb->data.samsiz, ASP_DECOP_CB_MAX_NUM_PCM_CH*sizeof(PAF_AudioSize), Cache_Type_ALLD, 0);
        Cache_wb(pAfCb->data.sample, ASP_DECOP_CB_MAX_NUM_PCM_CH*sizeof(PAF_AudioData *), Cache_Type_ALLD, 0);
        for (i=0; i<ASP_DECOP_CB_MAX_NUM_PCM_CH; i++)
        {
            Cache_wb(pAfCb->data.sample[i], decOpFrameLen*sizeof(PAF_AudioData), Cache_Type_ALLD, 0);
        }
        // FL: unnecessary since part of AF
        //for (i=0; i<PAF_MAX_NUM_PRIVATE_MD; i++)     // Write back metadata //QIN
        //{
        //    Cache_wb(&pAfCb->pafPrivateMetadata[i], sizeof(PAF_PrivateMetadata), Cache_Type_ALLD, 0);
        //}
    }
    Cache_wait();

    // Leave the gate
    GateMP_leave(gateHandle, key);
    
    return ASP_DECOP_CB_SOK;
}

// Start reads from circular buffer
Int cbReadStart(
    PAF_AST_DecOpCircBufCtl *pCbCtl,    // decoder output circular buffer control
    Int8 cbIdx                          // decoder output circular buffer index
)
{
    IArg key;
    GateMP_Handle gateHandle;
    PAF_AST_DecOpCircBuf *pCb;

    // Get gate handle
    gateHandle = pCbCtl->gateHandle;
    // Enter gate
    key = GateMP_enter(gateHandle);

    // Get circular buffer base pointer
    pCb = &((*pCbCtl->pXDecOpCb)[cbIdx]);
    
    // Invalidate circular buffer configuration
    Cache_inv(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    Cache_wait();
    
    //Log_info1("cbReadStart:afCb=0x%04x", (IArg)pCb->afCb); // FL: debug

    // update flags
    pCb->readerActiveFlag = 1;
    
    // (***) FL: revisit
    // Write back circular buffer configuration
    Cache_wb(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    Cache_wait();

    // Leave the gate
    GateMP_leave(gateHandle, key);

    return ASP_DECOP_CB_SOK;
}

// Stop reads from circular buffer
Int cbReadStop(
    PAF_AST_DecOpCircBufCtl *pCbCtl,    // decoder output circular buffer control
    Int8 cbIdx                          // decoder output circular buffer index
)
{
    IArg key;
    GateMP_Handle gateHandle;
    PAF_AST_DecOpCircBuf *pCb;

    // Get gate handle
    gateHandle = pCbCtl->gateHandle;
    // Enter gate
    key = GateMP_enter(gateHandle);

    // Get circular buffer base pointer
    pCb = &((*pCbCtl->pXDecOpCb)[cbIdx]);

    // Invalidate circular buffer configuration
    Cache_inv(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    Cache_wait();
    
    //Log_info1("cbReadStop:afCb=0x%04x", (IArg)pCb->afCb); // FL: debug

    // update flags
    pCb->readerActiveFlag = 0;
    
    // (***) FL: revisit
    // Write back circular buffer configuration
    Cache_wb(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    Cache_wait();

    // Leave the gate
    GateMP_leave(gateHandle, key);

    return ASP_DECOP_CB_SOK;
}

// Read audio frame from circular buffer
Int cbReadAf(
    PAF_AST_DecOpCircBufCtl *pCbCtl,    // decoder output circular buffer control
    Int8 cbIdx,                         // decoder output circular buffer index
    PAF_AudioFrame *pAfRd               // audio frame into which to read
)
{
    IArg key;
    GateMP_Handle gateHandle;
    PAF_AST_DecOpCircBuf *pCb;
    PAF_AudioFrame *pAfCb;
    PAF_ChannelMask_HD streamMask;
    Int8 i;
    Int16 j;

    // Get gate handle
    gateHandle = pCbCtl->gateHandle;
    // Enter gate
    key = GateMP_enter(gateHandle);

    // Get circular buffer base pointer
    pCb = &((*pCbCtl->pXDecOpCb)[cbIdx]);

    // (***) FL: revisit
    // Invalidate circular buffer configuration.
    Cache_inv(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    Cache_wait();

    //Log_info1("cbReadAf:afCb=0x%04x", (IArg)pCb->afCb); // FL: debug

    if ((pCb->writerActiveFlag == 1) && (pCb->emptyFlag == 1))
    {
        // This shouldn't occur:
        //  writer is active AND draining circular buffer
        //Log_info2("cbReadAf: ERROR: writerActiveFlag=%d, emptyFlag=%d", pCb->writerActiveFlag, pCb->emptyFlag); // FL: debug
        SW_BREAKPOINT; // FL: debug
        
        // Leave the gate
        GateMP_leave(gateHandle, key);
        
        return ASP_DECOP_CB_READ_INVSTATE;
    }

    if ((pCb->writerActiveFlag == 0) && (pCb->emptyFlag == 0))
    {
        //
        // No active writer, not draining circular buffer.
        // Skip UNDerflow check, mute output.
        //
        cbReadAfMute(pAfRd, pCb->strFrameLen);
        
        // Leave the gate
        GateMP_leave(gateHandle, key);

        return ASP_DECOP_CB_SOK;
    }
    
    // (writerActiveFlag,emptyFlag)=(1,0) and (0,1) are left
    // Here we are checking (1,0) state here
    if ((pCb->writerActiveFlag == 1))
    {
        // check underflow
        if (pCb->numAfCb <= 0)
        {
            // 
            // Increment underflow count.
            // Mute output on underflow.
            //
            pCb->errUndCnt++;
            cbReadAfMute(pAfRd, pCb->strFrameLen);
            //SW_BREAKPOINT; // FL: debug
            
            // Write back circular buffer configuration.
            Cache_wb(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
            Cache_wait();    
            
            // Leave the gate
            GateMP_leave(gateHandle, key);
            
            return ASP_DECOP_CB_READ_UNDERFLOW;
        }
    }
    
    if ((pCb->writerActiveFlag == 1) || (pCb->emptyFlag == 1))
    {
        //
        // Writer active or draining remaining frames in circular buffer.
        // Get next output audio frame.
        //
        
        // get pointer to current audio frame in circular buffer
        pAfCb = &pCb->afCb[pCb->afRdIdx];

        // (***) FL: revisit
        // Invalidate audio frame
        Cache_inv(pAfCb, sizeof(PAF_AudioFrame), Cache_Type_ALLD, 0);
        Cache_inv(pAfCb->data.samsiz, ASP_DECOP_CB_MAX_NUM_PCM_CH*sizeof(PAF_AudioSize), Cache_Type_ALLD, 0);
        for (i=0; i<pAfCb->numPrivateMetadata; i++) //QIN // FL: only invalidate numPrivateMetadata
        {
            //Cache_inv(&pAfCb->pafPrivateMetadata[i], sizeof(PAF_PrivateMetadata), Cache_Type_ALLD, 0); // FL: unnecessary since part of AF
            Cache_inv(pAfCb->pafPrivateMetadata[i].pMdBuf, pAfCb->pafPrivateMetadata[i].size, Cache_Type_ALLD, 0); // FL: only update metadata package size
        }
        Cache_wait();

        // compute stream mask
        streamMask = pAfRd->fxns->channelMask(pAfRd, pAfCb->channelConfigurationStream);

        // Invalidate PCM data
        for (i = 0; i < ASP_DECOP_CB_MAX_NUM_PCM_CH; i++)
        {
            if ((streamMask >> i) & 0x1)
            {
                Cache_inv(&pAfCb->data.sample[i][pCb->pcmRdIdx], pCb->strFrameLen*sizeof(PAF_AudioData), Cache_Type_ALLD, 0);
            }
        }
        Cache_wait();        
        
        // read audio frame information updated by decoder
        pAfRd->sampleDecode = pAfCb->sampleDecode;
        PAF_PROCESS_COPY(pAfRd->sampleProcess, pAfCb->sampleProcess);
        pAfRd->sampleRate = pAfCb->sampleRate;
        pAfRd->sampleCount = pCb->strFrameLen;
        pAfRd->channelConfigurationRequest = pAfCb->channelConfigurationRequest;
        pAfRd->channelConfigurationStream = pAfCb->channelConfigurationStream;
        
        // read metadata information updated by decoder //QIN
        pAfRd->bsMetadata_type     = pAfCb->bsMetadata_type;        /* non zero if metadata is attached. */
        pAfRd->pafBsMetadataUpdate = pAfCb->pafBsMetadataUpdate;    /* indicates whether bit-stream metadata update */
        pAfRd->numPrivateMetadata  = pAfCb->numPrivateMetadata;     /* number of valid private metadata (0 or 1 if metadata filtering enabled) */
        pAfRd->bsMetadata_offset   = pAfCb->bsMetadata_offset;      /* offset into audio frame for change in bsMetadata_type field */
        
        // read PCM samples
        for (i = 0; i < ASP_DECOP_CB_MAX_NUM_PCM_CH; i++)
        {
            if ((streamMask >> i) & 0x1)
            {
                for (j = 0; j < pCb->strFrameLen; j++)
                {
                    pAfRd->data.sample[i][j] = pAfCb->data.sample[i][pCb->pcmRdIdx+j];
                }

                pAfRd->data.samsiz[i] = pAfCb->data.samsiz[i];
            }
        }
        // read metadata //QIN
        for (i = 0; i < pAfCb->numPrivateMetadata; i++) // FL: only read numPrivateMetadata
        {
            // FL: this is done above
            ////Invalidate metadata data
            //Cache_inv(&pAfCb->pafPrivateMetadata[i], sizeof(PAF_PrivateMetadata), Cache_Type_ALLD, 0);
            //Cache_wait();        
            
            if ((pAfCb->pafPrivateMetadata[i].offset >= pCb->pcmRdIdx) 
                 &&(pAfCb->pafPrivateMetadata[i].offset < (pCb->pcmRdIdx + pCb->strFrameLen))
                 &&(pAfCb->pafPrivateMetadata[i].size))
            {
                // FL: this is done above
                ////Invalidate metadata data
                //Cache_inv(pAfCb->pafPrivateMetadata[i].pMdBuf, pAfCb->pafPrivateMetadata[i].size, Cache_Type_ALLD, 0);
                //Cache_wait();        
        
                // the offset is adjusted for segment [pCb->pcmRdIdx, (pCb->pcmRdIdx + pCb->pafFrameLen)]
                pAfRd->pafPrivateMetadata[i].offset = 0; //pAfCb->pafPrivateMetadata[i].offset - pCb->pcmRdIdx;
                pAfRd->pafPrivateMetadata[i].size   = pAfCb->pafPrivateMetadata[i].size;
                memcpy(pAfRd->pafPrivateMetadata[i].pMdBuf, pAfCb->pafPrivateMetadata[i].pMdBuf, pAfCb->pafPrivateMetadata[i].size);
            }
            else //reset un-used buf
            {
                pAfRd->pafPrivateMetadata[i].offset = 0;
                pAfRd->pafPrivateMetadata[i].size   = 0;
            }
        }
        
        pCb->pcmRdIdx += pCb->strFrameLen; // update PCM read index
        if (pCb->pcmRdIdx == pCb->decOpFrameLen)
        {
            // update audio frame read index
            pCb->afRdIdx++;
            if (pCb->afRdIdx >= pCb->maxNumAfCb)
            {
                pCb->afRdIdx = 0;
            }
            
            // update PCM read index
            pCb->pcmRdIdx = 0;
            
            // update number of audio frames in circular buffer
            pCb->numAfCb--;
        }
    }
    
    if (pCb->emptyFlag == 1)
    {
        //
        // Writer inactive, but remaining frames in circular buffer.
        // Update empty flag.
        //
        if (pCb->numAfCb <= 0)
        {
            pCb->emptyFlag = 0;
        }
    }
    
    // (***) FL: revisit
    // Write back circular buffer configuration.
    // NOTE: Probably only a subset of this information needs to be updated.
    Cache_wb(pCb, sizeof(PAF_AST_DecOpCircBuf), Cache_Type_ALLD, 0);
    Cache_wait();    
        
    // Leave the gate
    GateMP_leave(gateHandle, key);

    return ASP_DECOP_CB_SOK;
}

// Generate mute AF on circular buffer read
static Void cbReadAfMute(
    PAF_AudioFrame *pAfRd,      // audio frame into which to read
    Int16 strFrameLen           // stream frame length (output transaction size)
)
{
    PAF_ChannelMask_HD streamMask;
    Int8 i;
    
    pAfRd->sampleDecode = PAF_SOURCE_PCM;
    PAF_PROCESS_ZERO(pAfRd->sampleProcess);
    pAfRd->sampleRate = PAF_SAMPLERATE_48000HZ;
    pAfRd->sampleCount = strFrameLen;
    pAfRd->channelConfigurationRequest.full = 0;
    pAfRd->channelConfigurationRequest.part.sat = PAF_CC_SAT_SURROUND4;
    pAfRd->channelConfigurationRequest.part.sub = PAF_CC_SUB_ONE;
    pAfRd->channelConfigurationStream.full = 0;
    pAfRd->channelConfigurationStream.part.sat = PAF_CC_SAT_SURROUND4;
    pAfRd->channelConfigurationStream.part.sub = PAF_CC_SUB_ONE;
    
    // compute stream mask
    streamMask = pAfRd->fxns->channelMask(pAfRd, pAfRd->channelConfigurationStream);
    // Clear PCM data
    for (i = 0; i < ASP_DECOP_CB_MAX_NUM_PCM_CH; i++)
    {
        if ((streamMask >> i) & 0x1)
        {
            memset(pAfRd->data.sample[i], strFrameLen, 0);
        }
        pAfRd->data.samsiz[i] = 0;
    }
}