727 lines
21 KiB
C++
727 lines
21 KiB
C++
/*
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* Copyright (c) 2011 Apple Inc. All rights reserved.
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*
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* @APPLE_APACHE_LICENSE_HEADER_START@
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* @APPLE_APACHE_LICENSE_HEADER_END@
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*/
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/*
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File: ALACDecoder.cpp
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "ALACDecoder.h"
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#include "dplib.h"
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#include "aglib.h"
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#include "matrixlib.h"
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#include "ALACBitUtilities.h"
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#include "EndianPortable.h"
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// constants/data
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const uint32_t kMaxBitDepth = 32; // max allowed bit depth is 32
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// prototypes
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static void Zero16( int16_t * buffer, uint32_t numItems, uint32_t stride );
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static void Zero24( uint8_t * buffer, uint32_t numItems, uint32_t stride );
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static void Zero32( int32_t * buffer, uint32_t numItems, uint32_t stride );
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/*
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Constructor
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*/
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ALACDecoder::ALACDecoder() :
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mMixBufferU( nil ),
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mMixBufferV( nil ),
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mPredictor( nil ),
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mShiftBuffer( nil )
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{
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memset( &mConfig, 0, sizeof(mConfig) );
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}
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/*
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Destructor
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*/
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ALACDecoder::~ALACDecoder()
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{
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// delete the matrix mixing buffers
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if ( mMixBufferU )
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{
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free(mMixBufferU);
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mMixBufferU = NULL;
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}
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if ( mMixBufferV )
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{
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free(mMixBufferV);
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mMixBufferV = NULL;
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}
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// delete the dynamic predictor's "corrector" buffer
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// - note: mShiftBuffer shares memory with this buffer
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if ( mPredictor )
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{
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free(mPredictor);
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mPredictor = NULL;
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}
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}
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/*
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Init()
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- initialize the decoder with the given configuration
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*/
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int32_t ALACDecoder::Init( void * inMagicCookie, uint32_t inMagicCookieSize )
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{
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int32_t status = ALAC_noErr;
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ALACSpecificConfig theConfig;
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uint8_t * theActualCookie = (uint8_t *)inMagicCookie;
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uint32_t theCookieBytesRemaining = inMagicCookieSize;
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// For historical reasons the decoder needs to be resilient to magic cookies vended by older encoders.
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// As specified in the ALACMagicCookieDescription.txt document, there may be additional data encapsulating
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// the ALACSpecificConfig. This would consist of format ('frma') and 'alac' atoms which precede the
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// ALACSpecificConfig.
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// See ALACMagicCookieDescription.txt for additional documentation concerning the 'magic cookie'
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// skip format ('frma') atom if present
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if (theActualCookie[4] == 'f' && theActualCookie[5] == 'r' && theActualCookie[6] == 'm' && theActualCookie[7] == 'a')
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{
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theActualCookie += 12;
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theCookieBytesRemaining -= 12;
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}
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// skip 'alac' atom header if present
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if (theActualCookie[4] == 'a' && theActualCookie[5] == 'l' && theActualCookie[6] == 'a' && theActualCookie[7] == 'c')
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{
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theActualCookie += 12;
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theCookieBytesRemaining -= 12;
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}
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// read the ALACSpecificConfig
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if (theCookieBytesRemaining >= sizeof(ALACSpecificConfig))
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{
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memcpy(&theConfig, theActualCookie, sizeof(ALACSpecificConfig));
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theConfig.frameLength = Swap32BtoN(theConfig.frameLength);
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theConfig.maxRun = Swap16BtoN(theConfig.maxRun);
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theConfig.maxFrameBytes = Swap32BtoN(theConfig.maxFrameBytes);
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theConfig.avgBitRate = Swap32BtoN(theConfig.avgBitRate);
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theConfig.sampleRate = Swap32BtoN(theConfig.sampleRate);
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mConfig = theConfig;
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RequireAction( mConfig.compatibleVersion <= kALACVersion, return kALAC_ParamError; );
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// allocate mix buffers
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mMixBufferU = (int32_t *) calloc( mConfig.frameLength * sizeof(int32_t), 1 );
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mMixBufferV = (int32_t *) calloc( mConfig.frameLength * sizeof(int32_t), 1 );
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// allocate dynamic predictor buffer
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mPredictor = (int32_t *) calloc( mConfig.frameLength * sizeof(int32_t), 1 );
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// "shift off" buffer shares memory with predictor buffer
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mShiftBuffer = (uint16_t *) mPredictor;
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RequireAction( (mMixBufferU != nil) && (mMixBufferV != nil) && (mPredictor != nil),
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status = kALAC_MemFullError; goto Exit; );
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}
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else
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{
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status = kALAC_ParamError;
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}
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// skip to Channel Layout Info
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// theActualCookie += sizeof(ALACSpecificConfig);
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// Currently, the Channel Layout Info portion of the magic cookie (as defined in the
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// ALACMagicCookieDescription.txt document) is unused by the decoder.
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Exit:
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return status;
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}
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/*
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Decode()
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- the decoded samples are interleaved into the output buffer in the order they arrive in
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the bitstream
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*/
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int32_t ALACDecoder::Decode( BitBuffer * bits, uint8_t * sampleBuffer, uint32_t numSamples, uint32_t numChannels, uint32_t * outNumSamples )
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{
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BitBuffer shiftBits;
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uint32_t bits1, bits2;
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uint8_t tag;
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uint8_t elementInstanceTag;
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AGParamRec agParams;
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uint32_t channelIndex;
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int16_t coefsU[32]; // max possible size is 32 although NUMCOEPAIRS is the current limit
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int16_t coefsV[32];
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uint8_t numU, numV;
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uint8_t mixBits;
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int8_t mixRes;
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uint16_t unusedHeader;
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uint8_t escapeFlag;
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uint32_t chanBits;
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uint8_t bytesShifted;
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uint32_t shift;
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uint8_t modeU, modeV;
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uint32_t denShiftU, denShiftV;
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uint16_t pbFactorU, pbFactorV;
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uint16_t pb;
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int16_t * samples;
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int16_t * out16;
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uint8_t * out20;
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uint8_t * out24;
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int32_t * out32;
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uint8_t headerByte;
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uint8_t partialFrame;
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uint32_t extraBits;
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int32_t val;
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uint32_t i, j;
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int32_t status;
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RequireAction( (bits != nil) && (sampleBuffer != nil) && (outNumSamples != nil), return kALAC_ParamError; );
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RequireAction( numChannels > 0, return kALAC_ParamError; );
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mActiveElements = 0;
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channelIndex = 0;
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samples = (int16_t *) sampleBuffer;
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status = ALAC_noErr;
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*outNumSamples = numSamples;
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while ( status == ALAC_noErr )
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{
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// bail if we ran off the end of the buffer
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RequireAction( bits->cur < bits->end, status = kALAC_ParamError; goto Exit; );
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// copy global decode params for this element
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pb = mConfig.pb;
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// read element tag
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tag = BitBufferReadSmall( bits, 3 );
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switch ( tag )
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{
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case ID_SCE:
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case ID_LFE:
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{
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// mono/LFE channel
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elementInstanceTag = BitBufferReadSmall( bits, 4 );
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mActiveElements |= (1u << elementInstanceTag);
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// read the 12 unused header bits
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unusedHeader = (uint16_t) BitBufferRead( bits, 12 );
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RequireAction( unusedHeader == 0, status = kALAC_ParamError; goto Exit; );
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// read the 1-bit "partial frame" flag, 2-bit "shift-off" flag & 1-bit "escape" flag
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headerByte = (uint8_t) BitBufferRead( bits, 4 );
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partialFrame = headerByte >> 3;
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bytesShifted = (headerByte >> 1) & 0x3u;
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RequireAction( bytesShifted != 3, status = kALAC_ParamError; goto Exit; );
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shift = bytesShifted * 8;
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escapeFlag = headerByte & 0x1;
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chanBits = mConfig.bitDepth - (bytesShifted * 8);
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// check for partial frame to override requested numSamples
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if ( partialFrame != 0 )
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{
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numSamples = BitBufferRead( bits, 16 ) << 16;
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numSamples |= BitBufferRead( bits, 16 );
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}
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if ( escapeFlag == 0 )
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{
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// compressed frame, read rest of parameters
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mixBits = (uint8_t) BitBufferRead( bits, 8 );
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mixRes = (int8_t) BitBufferRead( bits, 8 );
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//Assert( (mixBits == 0) && (mixRes == 0) ); // no mixing for mono
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headerByte = (uint8_t) BitBufferRead( bits, 8 );
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modeU = headerByte >> 4;
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denShiftU = headerByte & 0xfu;
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headerByte = (uint8_t) BitBufferRead( bits, 8 );
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pbFactorU = headerByte >> 5;
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numU = headerByte & 0x1fu;
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for ( i = 0; i < numU; i++ )
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coefsU[i] = (int16_t) BitBufferRead( bits, 16 );
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// if shift active, skip the the shift buffer but remember where it starts
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if ( bytesShifted != 0 )
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{
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shiftBits = *bits;
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BitBufferAdvance( bits, (bytesShifted * 8) * numSamples );
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}
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// decompress
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set_ag_params( &agParams, mConfig.mb, (pb * pbFactorU) / 4, mConfig.kb, numSamples, numSamples, mConfig.maxRun );
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status = dyn_decomp( &agParams, bits, mPredictor, numSamples, chanBits, &bits1 );
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RequireNoErr( status, goto Exit; );
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if ( modeU == 0 )
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{
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unpc_block( mPredictor, mMixBufferU, numSamples, &coefsU[0], numU, chanBits, denShiftU );
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}
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else
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{
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// the special "numActive == 31" mode can be done in-place
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unpc_block( mPredictor, mPredictor, numSamples, nil, 31, chanBits, 0 );
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unpc_block( mPredictor, mMixBufferU, numSamples, &coefsU[0], numU, chanBits, denShiftU );
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}
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}
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else
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{
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//Assert( bytesShifted == 0 );
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// uncompressed frame, copy data into the mix buffer to use common output code
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shift = 32 - chanBits;
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if ( chanBits <= 16 )
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{
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for ( i = 0; i < numSamples; i++ )
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{
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val = (int32_t) BitBufferRead( bits, (uint8_t) chanBits );
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val = (val << shift) >> shift;
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mMixBufferU[i] = val;
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}
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}
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else
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{
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// BitBufferRead() can't read more than 16 bits at a time so break up the reads
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extraBits = chanBits - 16;
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for ( i = 0; i < numSamples; i++ )
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{
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val = (int32_t) BitBufferRead( bits, 16 );
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val = (val << 16) >> shift;
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mMixBufferU[i] = val | BitBufferRead( bits, (uint8_t) extraBits );
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}
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}
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mixBits = mixRes = 0;
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bits1 = chanBits * numSamples;
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bytesShifted = 0;
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}
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// now read the shifted values into the shift buffer
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if ( bytesShifted != 0 )
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{
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shift = bytesShifted * 8;
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//Assert( shift <= 16 );
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for ( i = 0; i < numSamples; i++ )
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mShiftBuffer[i] = (uint16_t) BitBufferRead( &shiftBits, (uint8_t) shift );
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}
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// convert 32-bit integers into output buffer
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switch ( mConfig.bitDepth )
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{
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case 16:
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out16 = &((int16_t *)sampleBuffer)[channelIndex];
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for ( i = 0, j = 0; i < numSamples; i++, j += numChannels )
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out16[j] = (int16_t) mMixBufferU[i];
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break;
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case 20:
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out20 = (uint8_t *)sampleBuffer + (channelIndex * 3);
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copyPredictorTo20( mMixBufferU, out20, numChannels, numSamples );
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break;
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case 24:
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out24 = (uint8_t *)sampleBuffer + (channelIndex * 3);
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if ( bytesShifted != 0 )
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copyPredictorTo24Shift( mMixBufferU, mShiftBuffer, out24, numChannels, numSamples, bytesShifted );
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else
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copyPredictorTo24( mMixBufferU, out24, numChannels, numSamples );
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break;
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case 32:
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out32 = &((int32_t *)sampleBuffer)[channelIndex];
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if ( bytesShifted != 0 )
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copyPredictorTo32Shift( mMixBufferU, mShiftBuffer, out32, numChannels, numSamples, bytesShifted );
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else
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copyPredictorTo32( mMixBufferU, out32, numChannels, numSamples);
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break;
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}
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channelIndex += 1;
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*outNumSamples = numSamples;
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break;
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}
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case ID_CPE:
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{
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// if decoding this pair would take us over the max channels limit, bail
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if ( (channelIndex + 2) > numChannels )
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goto NoMoreChannels;
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// stereo channel pair
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elementInstanceTag = BitBufferReadSmall( bits, 4 );
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mActiveElements |= (1u << elementInstanceTag);
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// read the 12 unused header bits
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unusedHeader = (uint16_t) BitBufferRead( bits, 12 );
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RequireAction( unusedHeader == 0, status = kALAC_ParamError; goto Exit; );
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// read the 1-bit "partial frame" flag, 2-bit "shift-off" flag & 1-bit "escape" flag
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headerByte = (uint8_t) BitBufferRead( bits, 4 );
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partialFrame = headerByte >> 3;
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bytesShifted = (headerByte >> 1) & 0x3u;
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RequireAction( bytesShifted != 3, status = kALAC_ParamError; goto Exit; );
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shift = bytesShifted * 8;
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escapeFlag = headerByte & 0x1;
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chanBits = mConfig.bitDepth - (bytesShifted * 8) + 1;
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// check for partial frame length to override requested numSamples
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if ( partialFrame != 0 )
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{
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numSamples = BitBufferRead( bits, 16 ) << 16;
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numSamples |= BitBufferRead( bits, 16 );
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}
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if ( escapeFlag == 0 )
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{
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// compressed frame, read rest of parameters
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mixBits = (uint8_t) BitBufferRead( bits, 8 );
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mixRes = (int8_t) BitBufferRead( bits, 8 );
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headerByte = (uint8_t) BitBufferRead( bits, 8 );
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modeU = headerByte >> 4;
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denShiftU = headerByte & 0xfu;
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headerByte = (uint8_t) BitBufferRead( bits, 8 );
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pbFactorU = headerByte >> 5;
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numU = headerByte & 0x1fu;
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for ( i = 0; i < numU; i++ )
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coefsU[i] = (int16_t) BitBufferRead( bits, 16 );
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headerByte = (uint8_t) BitBufferRead( bits, 8 );
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modeV = headerByte >> 4;
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denShiftV = headerByte & 0xfu;
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headerByte = (uint8_t) BitBufferRead( bits, 8 );
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pbFactorV = headerByte >> 5;
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numV = headerByte & 0x1fu;
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for ( i = 0; i < numV; i++ )
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coefsV[i] = (int16_t) BitBufferRead( bits, 16 );
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// if shift active, skip the interleaved shifted values but remember where they start
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if ( bytesShifted != 0 )
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{
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shiftBits = *bits;
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BitBufferAdvance( bits, (bytesShifted * 8) * 2 * numSamples );
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}
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// decompress and run predictor for "left" channel
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set_ag_params( &agParams, mConfig.mb, (pb * pbFactorU) / 4, mConfig.kb, numSamples, numSamples, mConfig.maxRun );
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status = dyn_decomp( &agParams, bits, mPredictor, numSamples, chanBits, &bits1 );
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RequireNoErr( status, goto Exit; );
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if ( modeU == 0 )
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{
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unpc_block( mPredictor, mMixBufferU, numSamples, &coefsU[0], numU, chanBits, denShiftU );
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}
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else
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{
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// the special "numActive == 31" mode can be done in-place
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unpc_block( mPredictor, mPredictor, numSamples, nil, 31, chanBits, 0 );
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unpc_block( mPredictor, mMixBufferU, numSamples, &coefsU[0], numU, chanBits, denShiftU );
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}
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// decompress and run predictor for "right" channel
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set_ag_params( &agParams, mConfig.mb, (pb * pbFactorV) / 4, mConfig.kb, numSamples, numSamples, mConfig.maxRun );
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status = dyn_decomp( &agParams, bits, mPredictor, numSamples, chanBits, &bits2 );
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RequireNoErr( status, goto Exit; );
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if ( modeV == 0 )
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{
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unpc_block( mPredictor, mMixBufferV, numSamples, &coefsV[0], numV, chanBits, denShiftV );
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}
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else
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{
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// the special "numActive == 31" mode can be done in-place
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unpc_block( mPredictor, mPredictor, numSamples, nil, 31, chanBits, 0 );
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unpc_block( mPredictor, mMixBufferV, numSamples, &coefsV[0], numV, chanBits, denShiftV );
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}
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}
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else
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{
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//Assert( bytesShifted == 0 );
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// uncompressed frame, copy data into the mix buffers to use common output code
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chanBits = mConfig.bitDepth;
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shift = 32 - chanBits;
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if ( chanBits <= 16 )
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{
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for ( i = 0; i < numSamples; i++ )
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{
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val = (int32_t) BitBufferRead( bits, (uint8_t) chanBits );
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val = (val << shift) >> shift;
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mMixBufferU[i] = val;
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val = (int32_t) BitBufferRead( bits, (uint8_t) chanBits );
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val = (val << shift) >> shift;
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mMixBufferV[i] = val;
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}
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}
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else
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{
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// BitBufferRead() can't read more than 16 bits at a time so break up the reads
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extraBits = chanBits - 16;
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for ( i = 0; i < numSamples; i++ )
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{
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val = (int32_t) BitBufferRead( bits, 16 );
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val = (val << 16) >> shift;
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mMixBufferU[i] = val | BitBufferRead( bits, (uint8_t)extraBits );
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|
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val = (int32_t) BitBufferRead( bits, 16 );
|
|
val = (val << 16) >> shift;
|
|
mMixBufferV[i] = val | BitBufferRead( bits, (uint8_t)extraBits );
|
|
}
|
|
}
|
|
|
|
bits1 = chanBits * numSamples;
|
|
bits2 = chanBits * numSamples;
|
|
mixBits = mixRes = 0;
|
|
bytesShifted = 0;
|
|
}
|
|
|
|
// now read the shifted values into the shift buffer
|
|
if ( bytesShifted != 0 )
|
|
{
|
|
shift = bytesShifted * 8;
|
|
//Assert( shift <= 16 );
|
|
|
|
for ( i = 0; i < (numSamples * 2); i += 2 )
|
|
{
|
|
mShiftBuffer[i + 0] = (uint16_t) BitBufferRead( &shiftBits, (uint8_t) shift );
|
|
mShiftBuffer[i + 1] = (uint16_t) BitBufferRead( &shiftBits, (uint8_t) shift );
|
|
}
|
|
}
|
|
|
|
// un-mix the data and convert to output format
|
|
// - note that mixRes = 0 means just interleave so we use that path for uncompressed frames
|
|
switch ( mConfig.bitDepth )
|
|
{
|
|
case 16:
|
|
out16 = &((int16_t *)sampleBuffer)[channelIndex];
|
|
unmix16( mMixBufferU, mMixBufferV, out16, numChannels, numSamples, mixBits, mixRes );
|
|
break;
|
|
case 20:
|
|
out20 = (uint8_t *)sampleBuffer + (channelIndex * 3);
|
|
unmix20( mMixBufferU, mMixBufferV, out20, numChannels, numSamples, mixBits, mixRes );
|
|
break;
|
|
case 24:
|
|
out24 = (uint8_t *)sampleBuffer + (channelIndex * 3);
|
|
unmix24( mMixBufferU, mMixBufferV, out24, numChannels, numSamples,
|
|
mixBits, mixRes, mShiftBuffer, bytesShifted );
|
|
break;
|
|
case 32:
|
|
out32 = &((int32_t *)sampleBuffer)[channelIndex];
|
|
unmix32( mMixBufferU, mMixBufferV, out32, numChannels, numSamples,
|
|
mixBits, mixRes, mShiftBuffer, bytesShifted );
|
|
break;
|
|
}
|
|
|
|
channelIndex += 2;
|
|
*outNumSamples = numSamples;
|
|
break;
|
|
}
|
|
|
|
case ID_CCE:
|
|
case ID_PCE:
|
|
{
|
|
// unsupported element, bail
|
|
//AssertNoErr( tag );
|
|
status = kALAC_ParamError;
|
|
break;
|
|
}
|
|
|
|
case ID_DSE:
|
|
{
|
|
// data stream element -- parse but ignore
|
|
status = this->DataStreamElement( bits );
|
|
break;
|
|
}
|
|
|
|
case ID_FIL:
|
|
{
|
|
// fill element -- parse but ignore
|
|
status = this->FillElement( bits );
|
|
break;
|
|
}
|
|
|
|
case ID_END:
|
|
{
|
|
// frame end, all done so byte align the frame and check for overruns
|
|
BitBufferByteAlign( bits, false );
|
|
//Assert( bits->cur == bits->end );
|
|
goto Exit;
|
|
}
|
|
}
|
|
|
|
#if ! DEBUG
|
|
// if we've decoded all of our channels, bail (but not in debug b/c we want to know if we're seeing bad bits)
|
|
// - this also protects us if the config does not match the bitstream or crap data bits follow the audio bits
|
|
if ( channelIndex >= numChannels )
|
|
break;
|
|
#endif
|
|
}
|
|
|
|
NoMoreChannels:
|
|
|
|
// if we get here and haven't decoded all of the requested channels, fill the remaining channels with zeros
|
|
for ( ; channelIndex < numChannels; channelIndex++ )
|
|
{
|
|
switch ( mConfig.bitDepth )
|
|
{
|
|
case 16:
|
|
{
|
|
int16_t * fill16 = &((int16_t *)sampleBuffer)[channelIndex];
|
|
Zero16( fill16, numSamples, numChannels );
|
|
break;
|
|
}
|
|
case 24:
|
|
{
|
|
uint8_t * fill24 = (uint8_t *)sampleBuffer + (channelIndex * 3);
|
|
Zero24( fill24, numSamples, numChannels );
|
|
break;
|
|
}
|
|
case 32:
|
|
{
|
|
int32_t * fill32 = &((int32_t *)sampleBuffer)[channelIndex];
|
|
Zero32( fill32, numSamples, numChannels );
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
Exit:
|
|
return status;
|
|
}
|
|
|
|
#if PRAGMA_MARK
|
|
#pragma mark -
|
|
#endif
|
|
|
|
/*
|
|
FillElement()
|
|
- they're just filler so we don't need 'em
|
|
*/
|
|
int32_t ALACDecoder::FillElement( BitBuffer * bits )
|
|
{
|
|
int16_t count;
|
|
|
|
// 4-bit count or (4-bit + 8-bit count) if 4-bit count == 15
|
|
// - plus this weird -1 thing I still don't fully understand
|
|
count = BitBufferReadSmall( bits, 4 );
|
|
if ( count == 15 )
|
|
count += (int16_t) BitBufferReadSmall( bits, 8 ) - 1;
|
|
|
|
BitBufferAdvance( bits, count * 8 );
|
|
|
|
RequireAction( bits->cur <= bits->end, return kALAC_ParamError; );
|
|
|
|
return ALAC_noErr;
|
|
}
|
|
|
|
/*
|
|
DataStreamElement()
|
|
- we don't care about data stream elements so just skip them
|
|
*/
|
|
int32_t ALACDecoder::DataStreamElement( BitBuffer * bits )
|
|
{
|
|
uint8_t element_instance_tag;
|
|
int32_t data_byte_align_flag;
|
|
uint16_t count;
|
|
|
|
// the tag associates this data stream element with a given audio element
|
|
element_instance_tag = BitBufferReadSmall( bits, 4 );
|
|
|
|
data_byte_align_flag = BitBufferReadOne( bits );
|
|
|
|
// 8-bit count or (8-bit + 8-bit count) if 8-bit count == 255
|
|
count = BitBufferReadSmall( bits, 8 );
|
|
if ( count == 255 )
|
|
count += BitBufferReadSmall( bits, 8 );
|
|
|
|
// the align flag means the bitstream should be byte-aligned before reading the following data bytes
|
|
if ( data_byte_align_flag )
|
|
BitBufferByteAlign( bits, false );
|
|
|
|
// skip the data bytes
|
|
BitBufferAdvance( bits, count * 8 );
|
|
|
|
RequireAction( bits->cur <= bits->end, return kALAC_ParamError; );
|
|
|
|
return ALAC_noErr;
|
|
}
|
|
|
|
/*
|
|
ZeroN()
|
|
- helper routines to clear out output channel buffers when decoding fewer channels than requested
|
|
*/
|
|
static void Zero16( int16_t * buffer, uint32_t numItems, uint32_t stride )
|
|
{
|
|
if ( stride == 1 )
|
|
{
|
|
memset( buffer, 0, numItems * sizeof(int16_t) );
|
|
}
|
|
else
|
|
{
|
|
for ( uint32_t index = 0; index < (numItems * stride); index += stride )
|
|
buffer[index] = 0;
|
|
}
|
|
}
|
|
|
|
static void Zero24( uint8_t * buffer, uint32_t numItems, uint32_t stride )
|
|
{
|
|
if ( stride == 1 )
|
|
{
|
|
memset( buffer, 0, numItems * 3 );
|
|
}
|
|
else
|
|
{
|
|
for ( uint32_t index = 0; index < (numItems * stride * 3); index += (stride * 3) )
|
|
{
|
|
buffer[index + 0] = 0;
|
|
buffer[index + 1] = 0;
|
|
buffer[index + 2] = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void Zero32( int32_t * buffer, uint32_t numItems, uint32_t stride )
|
|
{
|
|
if ( stride == 1 )
|
|
{
|
|
memset( buffer, 0, numItems * sizeof(int32_t) );
|
|
}
|
|
else
|
|
{
|
|
for ( uint32_t index = 0; index < (numItems * stride); index += stride )
|
|
buffer[index] = 0;
|
|
}
|
|
}
|