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lancir.h
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lancir.h
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//$ nobt
//$ nocpp
/**
* @file lancir.h
*
* @version 3.0.11
*
* @brief The self-contained header-only "LANCIR" image resizing algorithm.
*
* This is the self-contained inclusion file for the "LANCIR" image resizer,
* a part of the AVIR library. Features scalar, AVX, SSE2, and NEON
* optimizations as well as batched resizing technique which provides a better
* CPU cache performance.
*
* AVIR Copyright (c) 2015-2024 Aleksey Vaneev
*
* @mainpage
*
* @section intro_sec Introduction
*
* Description is available at https://github.com/avaneev/avir
*
* @section license License
*
* LICENSE:
*
* Copyright (c) 2015-2024 Aleksey Vaneev
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#ifndef AVIR_CLANCIR_INCLUDED
#define AVIR_CLANCIR_INCLUDED
#include <stdint.h>
#include <string.h>
#include <math.h>
#if defined( __AVX__ ) || defined( __AVX2__ )
#include <immintrin.h>
#define LANCIR_AVX
#define LANCIR_SSE2 // Some functions use SSE2; AVX has a higher priority.
#define LANCIR_ALIGN 32
#elif defined( __SSE4_2__ ) || defined( __SSE4_1__ ) || \
defined( __SSSE3__ ) || defined( __SSE3__ ) || defined( __SSE2__ ) || \
defined( __x86_64__ ) || defined( __amd64 ) || defined( _M_X64 ) || \
defined( _M_AMD64 ) || ( defined( _M_IX86_FP ) && _M_IX86_FP == 2 )
#if defined( _MSC_VER )
#include <intrin.h>
#else // defined( _MSC_VER )
#include <emmintrin.h>
#endif // defined( _MSC_VER )
#define LANCIR_SSE2
#define LANCIR_ALIGN 16
#elif defined( __aarch64__ ) || defined( __arm64 ) || defined( __ARM_NEON )
#include <arm_neon.h>
#define LANCIR_NEON
#define LANCIR_ALIGN 16
#else // NEON
#define LANCIR_ALIGN 4
#endif // NEON
namespace avir {
/**
* @brief LANCIR resizing parameters class.
*
* An object of this class, which can be allocated on stack, can be used to
* pass non-default parameters to the resizing algorithm. See the constructor
* for the default values.
*/
class CLancIRParams
{
public:
int SrcSSize; ///< Physical size of the source scanline, in elements (not
///< bytes). If this value is below 1, SrcWidth * ElCount will be
///< used.
int NewSSize; ///< Physical size of the destination scanline, in elements
///< (not bytes). If this value is below 1, NewWidth * ElCount will be
///< used.
double kx; ///< Resizing step - horizontal (one output pixel corresponds
///< to `k` input pixels). A downsizing factor if greater than 1.0;
///< upsizing factor if below or equal to 1.0. Multiply by -1 if you
///< would like to bypass `ox` and `oy` adjustment which is done by
///< default to produce a centered image. If this step value equals 0,
///< the step value will be chosen automatically.
double ky; ///< Resizing step - vertical. Same as `kx`.
double ox; ///< Start X pixel offset within the source image, can be
///< negative. A positive offset moves the image to the left.
///<
double oy; ///< Start Y pixel offset within the source image, can be
///< negative. A positive offset moves the image to the top.
///<
double la; ///< Lanczos window function's `a` parameter, greater or equal
///< to 2.0.
///<
/**
* Default constructor, with optional arguments that correspond to class
* variables.
*
* @param aSrcSSize Physical size of the source scanline.
* @param aNewSSize Physical size of the destination scanline.
* @param akx Resizing step - horizontal.
* @param aky Resizing step - vertical.
* @param aox Start X pixel offset.
* @param aoy Start Y pixel offset.
*/
CLancIRParams( const int aSrcSSize = 0, const int aNewSSize = 0,
const double akx = 0.0, const double aky = 0.0,
const double aox = 0.0, const double aoy = 0.0 )
: SrcSSize( aSrcSSize )
, NewSSize( aNewSSize )
, kx( akx )
, ky( aky )
, ox( aox )
, oy( aoy )
, la( 3.0 )
{
}
};
/**
* @brief LANCIR image resizer class.
*
* The object of this class can be used to resize 1-4 channel images to any
* required size. Resizing is performed by utilizing Lanczos filters, with
* 8-bit precision. This class offers a kind of "optimal" Lanczos resampling
* implementation.
*
* Object of this class can be allocated on stack.
*
* Note that object of this class does not free temporary buffers and
* variables after the resizeImage() function call (until object's
* destruction): these buffers are reused (or reallocated) on subsequent
* calls, thus making batch resizing of images faster. This means resizing is
* not thread-safe: a separate object should be created for each thread.
*/
class CLancIR
{
private:
CLancIR( const CLancIR& )
{
// Unsupported.
}
CLancIR& operator = ( const CLancIR& )
{
// Unsupported.
return( *this );
}
public:
CLancIR()
: FltBuf0( NULL )
, FltBuf0Len( 0 )
, spv0( NULL )
, spv0len( 0 )
, spv( NULL )
{
}
~CLancIR()
{
delete[] FltBuf0;
delete[] spv0;
}
/**
* @brief Function resizes an image.
*
* Performs input-to-output type conversion, if necessary.
*
* @param[in] SrcBuf Source image buffer.
* @param SrcWidth Source image width, in pixels.
* @param SrcHeight Source image height, in pixels.
* @param[out] NewBuf Buffer to accept the resized image. Cannot be equal
* to SrcBuf.
* @param NewWidth New image width, in pixels.
* @param NewHeight New image height, in pixels.
* @param ElCount The number of elements (channels) used to store each
* source and destination pixel (1-4).
* @tparam Tin Input buffer's element type. Can be uint8_t (0-255 value
* range), uint16_t (0-65535 value range), float (0-1 value range), double
* (0-1 value range). uint32_t type is treated as uint16_t. Signed integer
* types and larger integer types are unsupported.
* @tparam Tout Output buffer's element type, treated like `Tin`. If `Tin`
* and `Tout` types do not match, an output value scaling will be applied.
* Floating-point output will not clamped/clipped/saturated, integer
* output is always rounded and clamped.
* @return The number of available output scanlines. Equals to NewHeight,
* or 0 on function parameters error.
*/
template< typename Tin, typename Tout >
int resizeImage( const Tin* const SrcBuf, const int SrcWidth,
const int SrcHeight, Tout* const NewBuf, const int NewWidth,
const int NewHeight, const int ElCount,
const CLancIRParams* const aParams = NULL )
{
if(( SrcWidth < 0 ) | ( SrcHeight < 0 ) | ( NewWidth <= 0 ) |
( NewHeight <= 0 ) | ( SrcBuf == NULL ) | ( NewBuf == NULL ) |
( (const void*) SrcBuf == (const void*) NewBuf ))
{
return( 0 );
}
static const CLancIRParams DefParams;
const CLancIRParams& Params = ( aParams != NULL ?
*aParams : DefParams );
if( Params.la < 2.0 )
{
return( 0 );
}
const int OutSSize = NewWidth * ElCount;
const size_t NewScanlineSize = ( Params.NewSSize < 1 ?
OutSSize : Params.NewSSize );
if(( SrcWidth == 0 ) | ( SrcHeight == 0 ))
{
Tout* op = NewBuf;
int i;
for( i = 0; i < NewHeight; i++ )
{
memset( op, 0, OutSSize * sizeof( Tout ));
op += NewScanlineSize;
}
return( NewHeight );
}
const size_t SrcScanlineSize = ( Params.SrcSSize < 1 ?
SrcWidth * ElCount : Params.SrcSSize );
double ox = Params.ox;
double oy = Params.oy;
double kx;
double ky;
if( Params.kx >= 0.0 )
{
kx = ( Params.kx == 0.0 ?
(double) SrcWidth / NewWidth : Params.kx );
ox += ( kx - 1.0 ) * 0.5;
}
else
{
kx = -Params.kx;
}
if( Params.ky >= 0.0 )
{
ky = ( Params.ky == 0.0 ?
(double) SrcHeight / NewHeight : Params.ky );
oy += ( ky - 1.0 ) * 0.5;
}
else
{
ky = -Params.ky;
}
if( rfv.update( Params.la, ky, ElCount ))
{
rsv.reset();
rsh.reset();
}
CResizeFilters* rfh; // Pointer to resizing filters for horizontal
// resizing, may equal to `rfv` if the same stepping is in use.
if( kx == ky )
{
rfh = &rfv;
}
else
{
rfh = &rfh0;
if( rfh0.update( Params.la, kx, ElCount ))
{
rsh.reset();
}
}
rsv.update( SrcHeight, NewHeight, oy, rfv, spv );
rsh.update( SrcWidth, NewWidth, ox, *rfh );
// Calculate vertical progressive resizing's batch size. Progressive
// batching is used to try to keep addressing within the cache
// capacity. This technique definitely works well for single-threaded
// resizing on most CPUs, but may not provide an additional benefit
// for multi-threaded resizing, or in a system-wide high-load
// situations.
const size_t FltWidthE = ( rsh.padl + SrcWidth + rsh.padr ) * ElCount;
const double CacheSize = 5500000.0; // Tuned for various CPUs.
const double OpSize = (double) SrcScanlineSize * SrcHeight *
sizeof( Tin ) + (double) FltWidthE * NewHeight * sizeof( float );
int BatchSize = (int) ( NewHeight * CacheSize / ( OpSize + 1.0 ));
if( BatchSize < 8 )
{
BatchSize = 8;
}
if( BatchSize > NewHeight )
{
BatchSize = NewHeight;
}
// Allocate/resize intermediate buffers.
const int svs = ( rsv.padl + SrcHeight + rsv.padr ) * ElCount;
float* const pspv0 = spv0;
reallocBuf( spv0, spv, spv0len, ( svs > OutSSize ? svs : OutSSize ));
reallocBuf( FltBuf0, FltBuf, FltBuf0Len, FltWidthE * BatchSize );
if( spv0 != pspv0 )
{
rsv.updateSPO( rfv, spv );
}
// Prepare output-related constants.
const bool IsOutFloat = ( (Tout) 0.25 != 0 );
const int Clamp = ( sizeof( Tout ) == 1 ? 255 : 65535 );
const float OutMul = ( IsOutFloat ? 1.0f : (float) Clamp ) /
( (Tin) 0.25 != 0 ? 1 : ( sizeof( Tin ) == 1 ? 255 : 65535 ));
// Perform batched resizing.
const CResizePos* rpv = rsv.pos;
Tout* opn = NewBuf;
int bl = NewHeight;
while( bl > 0 )
{
const int bc = ( bl > BatchSize ? BatchSize : bl );
int kl = rfv.KernelLen;
const Tin* ip = SrcBuf;
float* op = FltBuf + rsh.padl * ElCount;
const int so = (int) rpv[ 0 ].so;
float* const sp = spv + so * ElCount;
int cc = (int) rpv[ bc - 1 ].so - so + kl; // Pixel copy count.
int rl = 0; // Leftmost pixel's replication count.
int rr = 0; // Rightmost pixel's replication count.
const int socc = so + cc;
const int spe = rsv.padl + SrcHeight;
// Calculate scanline copying and padding parameters, depending on
// the batch's size and its vertical offset.
if( so < rsv.padl )
{
if( socc <= rsv.padl )
{
rl = cc;
cc = 0;
}
else
{
if( socc > spe )
{
rr = socc - spe;
cc -= rr;
}
rl = rsv.padl - so;
cc -= rl;
}
}
else
{
if( so >= spe )
{
rr = cc;
cc = 0;
ip += SrcHeight * SrcScanlineSize;
}
else
{
if( socc > spe )
{
rr = socc - spe;
cc -= rr;
}
ip += ( so - rsv.padl ) * SrcScanlineSize;
}
}
// Batched vertical resizing.
int i;
if( ElCount == 1 )
{
for( i = 0; i < SrcWidth; i++ )
{
copyScanline1v( ip, SrcScanlineSize, sp, cc, rl, rr );
resize1< false >( NULL, op, FltWidthE, rpv, kl, bc );
ip += 1;
op += 1;
}
}
else
if( ElCount == 2 )
{
for( i = 0; i < SrcWidth; i++ )
{
copyScanline2v( ip, SrcScanlineSize, sp, cc, rl, rr );
resize2< false >( NULL, op, FltWidthE, rpv, kl, bc );
ip += 2;
op += 2;
}
}
else
if( ElCount == 3 )
{
for( i = 0; i < SrcWidth; i++ )
{
copyScanline3v( ip, SrcScanlineSize, sp, cc, rl, rr );
resize3< false >( NULL, op, FltWidthE, rpv, kl, bc );
ip += 3;
op += 3;
}
}
else // ElCount == 4
{
for( i = 0; i < SrcWidth; i++ )
{
copyScanline4v( ip, SrcScanlineSize, sp, cc, rl, rr );
resize4< false >( NULL, op, FltWidthE, rpv, kl, bc );
ip += 4;
op += 4;
}
}
// Perform horizontal resizing batch, and produce final output.
float* ipf = FltBuf;
kl = rfh -> KernelLen;
if( ElCount == 1 )
{
for( i = 0; i < bc; i++ )
{
padScanline1h( ipf, rsh, SrcWidth );
resize1< true >( ipf, spv, 1, rsh.pos, kl, NewWidth );
copyToOutput( spv, opn, OutSSize, Clamp, IsOutFloat,
OutMul );
ipf += FltWidthE;
opn += NewScanlineSize;
}
}
else
if( ElCount == 2 )
{
for( i = 0; i < bc; i++ )
{
padScanline2h( ipf, rsh, SrcWidth );
resize2< true >( ipf, spv, 2, rsh.pos, kl, NewWidth );
copyToOutput( spv, opn, OutSSize, Clamp, IsOutFloat,
OutMul );
ipf += FltWidthE;
opn += NewScanlineSize;
}
}
else
if( ElCount == 3 )
{
for( i = 0; i < bc; i++ )
{
padScanline3h( ipf, rsh, SrcWidth );
resize3< true >( ipf, spv, 3, rsh.pos, kl, NewWidth );
copyToOutput( spv, opn, OutSSize, Clamp, IsOutFloat,
OutMul );
ipf += FltWidthE;
opn += NewScanlineSize;
}
}
else // ElCount == 4
{
for( i = 0; i < bc; i++ )
{
padScanline4h( ipf, rsh, SrcWidth );
resize4< true >( ipf, spv, 4, rsh.pos, kl, NewWidth );
copyToOutput( spv, opn, OutSSize, Clamp, IsOutFloat,
OutMul );
ipf += FltWidthE;
opn += NewScanlineSize;
}
}
rpv += bc;
bl -= bc;
}
return( NewHeight );
}
/**
* @brief Legacy resizing function. Not recommended for new projects.
*
* See the prior resizeImage() function and CLancIRParams class for
* details.
*
* @param[in] SrcBuf Source image buffer.
* @param SrcWidth Source image width, in pixels.
* @param SrcHeight Source image height, in pixels.
* @param SrcSSize Physical size of the source scanline, in elements (not
* bytes).
* @param[out] NewBuf Buffer to accept the resized image. Cannot be equal
* to SrcBuf.
* @param NewWidth New image width, in pixels.
* @param NewHeight New image height, in pixels.
* @param NewSSize Physical size of the destination scanline, in elements
* (not bytes).
* @param ElCount The number of elements (channels) used to store each
* source and destination pixel (1-4).
* @param kx0 Resizing step - horizontal.
* @param ky0 Resizing step - vertical. Same as `kx0`.
* @param ox Start X pixel offset within the source image.
* @param oy Start Y pixel offset within the source image.
* @tparam Tin Input buffer's element type.
* @tparam Tout Output buffer's element type.
* @return The number of available output scanlines. Equals to NewHeight,
* or 0 on function parameters error.
*/
template< typename Tin, typename Tout >
int resizeImage( const Tin* const SrcBuf, const int SrcWidth,
const int SrcHeight, const int SrcSSize, Tout* const NewBuf,
const int NewWidth, const int NewHeight, const int NewSSize,
const int ElCount, const double kx0 = 0.0, const double ky0 = 0.0,
double ox = 0.0, double oy = 0.0 )
{
const CLancIRParams Params( SrcSSize, NewSSize, kx0, ky0, ox, oy );
return( resizeImage( SrcBuf, SrcWidth, SrcHeight, NewBuf, NewWidth,
NewHeight, ElCount, &Params ));
}
protected:
float* FltBuf0; ///< Intermediate resizing buffer.
size_t FltBuf0Len; ///< Length of `FltBuf0`.
float* FltBuf; ///< Address-aligned `FltBuf0`.
float* spv0; ///< Scanline buffer for vertical resizing, also used at the
///< output stage.
///<
int spv0len; ///< Length of `spv0`.
float* spv; ///< Address-aligned `spv0`.
/**
* Function reallocates a typed buffer if its current length is smaller
* than the required length.
*
* @param buf0 Reference to the pointer of the previously allocated
* buffer.
* @param buf Reference to address-aligned `buf0` pointer.
* @param len The current length of the `buf0`.
* @param newlen A new required length.
* @tparam Tb Buffer element type.
* @tparam Tl Length variable type.
*/
template< typename Tb, typename Tl >
static void reallocBuf( Tb*& buf0, Tb*& buf, Tl& len, Tl newlen )
{
newlen += LANCIR_ALIGN;
if( newlen > len )
{
if( buf0 != NULL )
{
delete[] buf0;
buf0 = NULL;
len = 0;
}
buf0 = new Tb[ newlen ];
len = newlen;
buf = (Tb*) (( (uintptr_t) buf0 + LANCIR_ALIGN - 1 ) &
~(uintptr_t) ( LANCIR_ALIGN - 1 ));
}
}
/**
* Function reallocates a typed buffer if its current length is smaller
* than the required length.
*
* @param buf Reference to the pointer of the previously allocated buffer;
* address alignment will not be applied.
* @param len The current length of the `buf0`.
* @param newlen A new required length.
* @tparam Tb Buffer element type.
* @tparam Tl Length variable type.
*/
template< typename Tb, typename Tl >
static void reallocBuf( Tb*& buf, Tl& len, const Tl newlen )
{
if( newlen > len )
{
if( buf != NULL )
{
delete[] buf;
buf = NULL;
len = 0;
}
buf = new Tb[ newlen ];
len = newlen;
}
}
class CResizeScanline;
/**
* Class implements fractional delay filter bank calculation.
*/
class CResizeFilters
{
friend class CResizeScanline;
public:
int KernelLen; ///< Resampling filter kernel's length, taps. Available
///< after the update() function call. Always an even value,
///< should not be lesser than 4.
CResizeFilters()
: Filters( NULL )
, FiltersLen( 0 )
, la( 0.0 )
{
memset( Bufs0, 0, sizeof( Bufs0 ));
memset( Bufs0Len, 0, sizeof( Bufs0Len ));
}
~CResizeFilters()
{
int i;
for( i = 0; i < BufCount; i++ )
{
delete[] Bufs0[ i ];
}
delete[] Filters;
}
/**
* Function updates the resizing filter bank.
*
* @param la0 Lanczos `a` parameter value (greater or equal to 2.0),
* can be fractional.
* @param k0 Resizing step.
* @param ElCount0 Image's element count, may be used for SIMD filter
* tap replication.
* @return `true` if an update occured and scanline resizing positions
* should be updated unconditionally.
*/
bool update( const double la0, const double k0, const int ElCount0 )
{
if( la0 == la && k0 == k && ElCount0 == ElCount )
{
return( false );
}
const double NormFreq = ( k0 <= 1.0 ? 1.0 : 1.0 / k0 );
Freq = 3.1415926535897932 * NormFreq;
FreqA = Freq / la0;
Len2 = la0 / NormFreq;
fl2 = (int) ceil( Len2 );
KernelLen = fl2 + fl2;
#if LANCIR_ALIGN > 4
ElRepl = ElCount0;
KernelLenA = KernelLen * ElRepl;
const int elalign =
(int) ( LANCIR_ALIGN / sizeof( float )) - 1;
KernelLenA = ( KernelLenA + elalign ) & ~elalign;
#else // LANCIR_ALIGN > 4
ElRepl = 1;
KernelLenA = KernelLen;
#endif // LANCIR_ALIGN > 4
FracCount = 1000; // Enough for Lanczos implicit 8-bit precision.
la = 0.0;
reallocBuf( Filters, FiltersLen, FracCount + 1 );
memset( Filters, 0, FiltersLen * sizeof( Filters[ 0 ]));
setBuf( 0 );
la = la0;
k = k0;
ElCount = ElCount0;
return( true );
}
/**
* Function returns filter at the specified fractional offset. This
* function can only be called after a prior update() function call.
*
* @param x Fractional offset, [0; 1].
*/
const float* getFilter( const double x )
{
const int Frac = (int) ( x * FracCount + 0.5 );
float* flt = Filters[ Frac ];
if( flt != NULL )
{
return( flt );
}
flt = Bufs[ CurBuf ] + CurBufFill * KernelLenA;
Filters[ Frac ] = flt;
CurBufFill++;
if( CurBufFill == BufLen )
{
setBuf( CurBuf + 1 );
}
makeFilterNorm( flt, 1.0 - (double) Frac / FracCount );
if( ElRepl > 1 )
{
replicateFilter( flt, KernelLen, ElRepl );
}
return( flt );
}
protected:
double Freq; ///< Circular frequency of the filter.
double FreqA; ///< Circular frequency of the window function.
double Len2; ///< Half resampling filter's length, unrounded.
int fl2; ///< Half resampling filter's length, integer.
int FracCount; ///< The number of fractional positions for which
///< filters can be created.
///<
int KernelLenA; ///< SIMD-aligned and replicated filter kernel's
///< length.
///<
int ElRepl; ///< The number of repetitions of each filter tap.
static const int BufCount = 4; ///< The maximal number of buffers that
///< can be in use.
///<
static const int BufLen = 256; ///< The number of fractional filters
///< a single buffer may contain. Both `BufLen` and `BufCount`
///< should correspond to the `FracCount` used.
float* Bufs0[ BufCount ]; ///< Buffers that hold all filters,
///< original.
///<
int Bufs0Len[ BufCount ]; ///< Allocated lengthes in `Bufs0`, in
///< `float` elements.
///<
float* Bufs[ BufCount ]; ///< Address-aligned `Bufs0`.
int CurBuf; ///< Filter buffer currently being filled.
int CurBufFill; ///< The number of fractional positions filled in the
///< current filter buffer.
///<
float** Filters; ///< Fractional delay filters for all positions.
///< A particular pointer equals NULL if a filter for such
///< position has not been created yet.
int FiltersLen; ///< Allocated length of Filters, in elements.
double la; ///< Current `la`.
double k; ///< Current `k`.
int ElCount; ///< Current `ElCount`.
/**
* Function changes the buffer currently being filled, check its
* size and reallocates it if necessary, then resets its fill counter.
*
* @param bi New current buffer index.
*/
void setBuf( const int bi )
{
reallocBuf( Bufs0[ bi ], Bufs[ bi ], Bufs0Len[ bi ],
BufLen * KernelLenA );
CurBuf = bi;
CurBufFill = 0;
}
/**
* @brief Sine-wave signal generator class.
*
* Class implements sine-wave signal generator without biasing, with
* constructor-based initialization only. This generator uses an
* oscillator instead of the `sin` function.
*/
class CSineGen
{
public:
/**
* Constructor initializes `this` sine-wave signal generator.
*
* @param si Sine function increment, in radians.
* @param ph Starting phase, in radians. Add `0.5 x PI` for a
* cosine function.
*/
CSineGen( const double si, const double ph )
: svalue1( sin( ph ))
, svalue2( sin( ph - si ))
, sincr( 2.0 * cos( si ))
{
}
/**
* @return The next value of the sine-wave, without biasing.
*/
double generate()
{
const double res = svalue1;
svalue1 = sincr * res - svalue2;
svalue2 = res;
return( res );
}
private:
double svalue1; ///< Current sine value.
double svalue2; ///< Previous sine value.
double sincr; ///< Sine value increment.
};
/**
* Function creates a filter for the specified fractional delay. The
* update() function should be called prior to calling this function.
* The created filter is normalized (DC gain=1).
*
* @param[out] op Output filter buffer.
* @param FracDelay Fractional delay, 0 to 1, inclusive.
*/
void makeFilterNorm( float* op, const double FracDelay ) const
{
CSineGen f( Freq, Freq * ( FracDelay - fl2 ));
CSineGen fw( FreqA, FreqA * ( FracDelay - fl2 ));
float* op0 = op;
double s = 0.0;
double ut;
int t = -fl2;
if( t + FracDelay < -Len2 )
{
f.generate();
fw.generate();
*op = (float) 0;
op++;
t++;
}
int IsZeroX = ( fabs( FracDelay - 1.0 ) < 2.3e-13 );
int mt = 0 - IsZeroX;
IsZeroX |= ( fabs( FracDelay ) < 2.3e-13 );
while( t < mt )
{
ut = t + FracDelay;
*op = (float) ( f.generate() * fw.generate() / ( ut * ut ));
s += *op;
op++;
t++;
}
if( IsZeroX ) // t+FracDelay==0
{
*op = (float) ( Freq * FreqA );
s += *op;
f.generate();
fw.generate();
}
else
{
ut = FracDelay; // t==0
*op = (float) ( f.generate() * fw.generate() / ( ut * ut ));
s += *op;
}
mt = fl2 - 2;
while( t < mt )
{
op++;
t++;
ut = t + FracDelay;
*op = (float) ( f.generate() * fw.generate() / ( ut * ut ));
s += *op;
}
op++;
ut = t + 1 + FracDelay;
if( ut > Len2 )
{
*op = (float) 0;
}
else
{
*op = (float) ( f.generate() * fw.generate() / ( ut * ut ));
s += *op;
}
s = 1.0 / s;
t = (int) ( op - op0 + 1 );
while( t != 0 )
{
*op0 = (float) ( *op0 * s );
op0++;
t--;
}
}
/**
* Function replicates taps of the specified filter so that it can
* be used with SIMD loading instructions. This function works
* "in-place".
*
* @param[in,out] p Filter buffer pointer, should be sized to contain
* `kl * erp` elements.
* @param kl Filter kernel's length, in taps.
* @param erp The number of repetitions to apply.
*/
static void replicateFilter( float* const p, const int kl,
const int erp )
{
const float* ip = p + kl - 1;
float* op = p + ( kl - 1 ) * erp;
int c = kl;