fuchsia / third_party / android / platform / external / aac / 4899e80a1725d07d028df4610e39b0c278a6252a / . / libSBRdec / src / transcendent.h

/* ----------------------------------------------------------------------------- | |

Software License for The Fraunhofer FDK AAC Codec Library for Android | |

© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten | |

Forschung e.V. All rights reserved. | |

1. INTRODUCTION | |

The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software | |

that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding | |

scheme for digital audio. This FDK AAC Codec software is intended to be used on | |

a wide variety of Android devices. | |

AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient | |

general perceptual audio codecs. AAC-ELD is considered the best-performing | |

full-bandwidth communications codec by independent studies and is widely | |

deployed. AAC has been standardized by ISO and IEC as part of the MPEG | |

specifications. | |

Patent licenses for necessary patent claims for the FDK AAC Codec (including | |

those of Fraunhofer) may be obtained through Via Licensing | |

(www.vialicensing.com) or through the respective patent owners individually for | |

the purpose of encoding or decoding bit streams in products that are compliant | |

with the ISO/IEC MPEG audio standards. Please note that most manufacturers of | |

Android devices already license these patent claims through Via Licensing or | |

directly from the patent owners, and therefore FDK AAC Codec software may | |

already be covered under those patent licenses when it is used for those | |

licensed purposes only. | |

Commercially-licensed AAC software libraries, including floating-point versions | |

with enhanced sound quality, are also available from Fraunhofer. Users are | |

encouraged to check the Fraunhofer website for additional applications | |

information and documentation. | |

2. COPYRIGHT LICENSE | |

Redistribution and use in source and binary forms, with or without modification, | |

are permitted without payment of copyright license fees provided that you | |

satisfy the following conditions: | |

You must retain the complete text of this software license in redistributions of | |

the FDK AAC Codec or your modifications thereto in source code form. | |

You must retain the complete text of this software license in the documentation | |

and/or other materials provided with redistributions of the FDK AAC Codec or | |

your modifications thereto in binary form. You must make available free of | |

charge copies of the complete source code of the FDK AAC Codec and your | |

modifications thereto to recipients of copies in binary form. | |

The name of Fraunhofer may not be used to endorse or promote products derived | |

from this library without prior written permission. | |

You may not charge copyright license fees for anyone to use, copy or distribute | |

the FDK AAC Codec software or your modifications thereto. | |

Your modified versions of the FDK AAC Codec must carry prominent notices stating | |

that you changed the software and the date of any change. For modified versions | |

of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android" | |

must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK | |

AAC Codec Library for Android." | |

3. NO PATENT LICENSE | |

NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without | |

limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE. | |

Fraunhofer provides no warranty of patent non-infringement with respect to this | |

software. | |

You may use this FDK AAC Codec software or modifications thereto only for | |

purposes that are authorized by appropriate patent licenses. | |

4. DISCLAIMER | |

This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright | |

holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, | |

including but not limited to the implied warranties of merchantability and | |

fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR | |

CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, | |

or consequential damages, including but not limited to procurement of substitute | |

goods or services; loss of use, data, or profits, or business interruption, | |

however caused and on any theory of liability, whether in contract, strict | |

liability, or tort (including negligence), arising in any way out of the use of | |

this software, even if advised of the possibility of such damage. | |

5. CONTACT INFORMATION | |

Fraunhofer Institute for Integrated Circuits IIS | |

Attention: Audio and Multimedia Departments - FDK AAC LL | |

Am Wolfsmantel 33 | |

91058 Erlangen, Germany | |

www.iis.fraunhofer.de/amm | |

amm-info@iis.fraunhofer.de | |

----------------------------------------------------------------------------- */ | |

/**************************** SBR decoder library ****************************** | |

Author(s): | |

Description: | |

*******************************************************************************/ | |

/*! | |

\file | |

\brief FDK Fixed Point Arithmetic Library Interface | |

*/ | |

#ifndef TRANSCENDENT_H | |

#define TRANSCENDENT_H | |

#include "sbrdecoder.h" | |

#include "sbr_rom.h" | |

/************************************************************************/ | |

/*! | |

\brief Get number of octaves between frequencies a and b | |

The Result is scaled with 1/8. | |

The valid range for a and b is 1 to LOG_DUALIS_TABLE_SIZE. | |

\return ld(a/b) / 8 | |

*/ | |

/************************************************************************/ | |

static inline FIXP_SGL FDK_getNumOctavesDiv8(INT a, /*!< lower band */ | |

INT b) /*!< upper band */ | |

{ | |

return ((SHORT)((LONG)(CalcLdInt(b) - CalcLdInt(a)) >> (FRACT_BITS - 3))); | |

} | |

/************************************************************************/ | |

/*! | |

\brief Add two values given by mantissa and exponent. | |

Mantissas are in fract format with values between 0 and 1. <br> | |

The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br> | |

*/ | |

/************************************************************************/ | |

inline void FDK_add_MantExp(FIXP_SGL a_m, /*!< Mantissa of 1st operand a */ | |

SCHAR a_e, /*!< Exponent of 1st operand a */ | |

FIXP_SGL b_m, /*!< Mantissa of 2nd operand b */ | |

SCHAR b_e, /*!< Exponent of 2nd operand b */ | |

FIXP_SGL *ptrSum_m, /*!< Mantissa of result */ | |

SCHAR *ptrSum_e) /*!< Exponent of result */ | |

{ | |

FIXP_DBL accu; | |

int shift; | |

int shiftAbs; | |

FIXP_DBL shiftedMantissa; | |

FIXP_DBL otherMantissa; | |

/* Equalize exponents of the summands. | |

For the smaller summand, the exponent is adapted and | |

for compensation, the mantissa is shifted right. */ | |

shift = (int)(a_e - b_e); | |

shiftAbs = (shift > 0) ? shift : -shift; | |

shiftAbs = (shiftAbs < DFRACT_BITS - 1) ? shiftAbs : DFRACT_BITS - 1; | |

shiftedMantissa = (shift > 0) ? (FX_SGL2FX_DBL(b_m) >> shiftAbs) | |

: (FX_SGL2FX_DBL(a_m) >> shiftAbs); | |

otherMantissa = (shift > 0) ? FX_SGL2FX_DBL(a_m) : FX_SGL2FX_DBL(b_m); | |

*ptrSum_e = (shift > 0) ? a_e : b_e; | |

accu = (shiftedMantissa >> 1) + (otherMantissa >> 1); | |

/* shift by 1 bit to avoid overflow */ | |

if ((accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || | |

(accu <= FL2FXCONST_DBL(-0.5f))) | |

*ptrSum_e += 1; | |

else | |

accu = (shiftedMantissa + otherMantissa); | |

*ptrSum_m = FX_DBL2FX_SGL(accu); | |

} | |

inline void FDK_add_MantExp(FIXP_DBL a, /*!< Mantissa of 1st operand a */ | |

SCHAR a_e, /*!< Exponent of 1st operand a */ | |

FIXP_DBL b, /*!< Mantissa of 2nd operand b */ | |

SCHAR b_e, /*!< Exponent of 2nd operand b */ | |

FIXP_DBL *ptrSum, /*!< Mantissa of result */ | |

SCHAR *ptrSum_e) /*!< Exponent of result */ | |

{ | |

FIXP_DBL accu; | |

int shift; | |

int shiftAbs; | |

FIXP_DBL shiftedMantissa; | |

FIXP_DBL otherMantissa; | |

/* Equalize exponents of the summands. | |

For the smaller summand, the exponent is adapted and | |

for compensation, the mantissa is shifted right. */ | |

shift = (int)(a_e - b_e); | |

shiftAbs = (shift > 0) ? shift : -shift; | |

shiftAbs = (shiftAbs < DFRACT_BITS - 1) ? shiftAbs : DFRACT_BITS - 1; | |

shiftedMantissa = (shift > 0) ? (b >> shiftAbs) : (a >> shiftAbs); | |

otherMantissa = (shift > 0) ? a : b; | |

*ptrSum_e = (shift > 0) ? a_e : b_e; | |

accu = (shiftedMantissa >> 1) + (otherMantissa >> 1); | |

/* shift by 1 bit to avoid overflow */ | |

if ((accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || | |

(accu <= FL2FXCONST_DBL(-0.5f))) | |

*ptrSum_e += 1; | |

else | |

accu = (shiftedMantissa + otherMantissa); | |

*ptrSum = accu; | |

} | |

/************************************************************************/ | |

/*! | |

\brief Divide two values given by mantissa and exponent. | |

Mantissas are in fract format with values between 0 and 1. <br> | |

The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br> | |

For performance reasons, the division is based on a table lookup | |

which limits accuracy. | |

*/ | |

/************************************************************************/ | |

static inline void FDK_divide_MantExp( | |

FIXP_SGL a_m, /*!< Mantissa of dividend a */ | |

SCHAR a_e, /*!< Exponent of dividend a */ | |

FIXP_SGL b_m, /*!< Mantissa of divisor b */ | |

SCHAR b_e, /*!< Exponent of divisor b */ | |

FIXP_SGL *ptrResult_m, /*!< Mantissa of quotient a/b */ | |

SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */ | |

{ | |

int preShift, postShift, index, shift; | |

FIXP_DBL ratio_m; | |

FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f); | |

preShift = CntLeadingZeros(FX_SGL2FX_DBL(b_m)); | |

/* | |

Shift b into the range from 0..INV_TABLE_SIZE-1, | |

E.g. 10 bits must be skipped for INV_TABLE_BITS 8: | |

- leave 8 bits as index for table | |

- skip sign bit, | |

- skip first bit of mantissa, because this is always the same (>0.5) | |

We are dealing with energies, so we need not care | |

about negative numbers | |

*/ | |

/* | |

The first interval has half width so the lowest bit of the index is | |

needed for a doubled resolution. | |

*/ | |

shift = (FRACT_BITS - 2 - INV_TABLE_BITS - preShift); | |

index = (shift < 0) ? (LONG)b_m << (-shift) : (LONG)b_m >> shift; | |

/* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */ | |

index &= (1 << (INV_TABLE_BITS + 1)) - 1; | |

/* Remove offset of half an interval */ | |

index--; | |

/* Now the lowest bit is shifted out */ | |

index = index >> 1; | |

/* Fetch inversed mantissa from table: */ | |

bInv_m = (index < 0) ? bInv_m : FDK_sbrDecoder_invTable[index]; | |

/* Multiply a with the inverse of b: */ | |

ratio_m = (index < 0) ? FX_SGL2FX_DBL(a_m >> 1) : fMultDiv2(bInv_m, a_m); | |

postShift = CntLeadingZeros(ratio_m) - 1; | |

*ptrResult_m = FX_DBL2FX_SGL(ratio_m << postShift); | |

*ptrResult_e = a_e - b_e + 1 + preShift - postShift; | |

} | |

static inline void FDK_divide_MantExp( | |

FIXP_DBL a_m, /*!< Mantissa of dividend a */ | |

SCHAR a_e, /*!< Exponent of dividend a */ | |

FIXP_DBL b_m, /*!< Mantissa of divisor b */ | |

SCHAR b_e, /*!< Exponent of divisor b */ | |

FIXP_DBL *ptrResult_m, /*!< Mantissa of quotient a/b */ | |

SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */ | |

{ | |

int preShift, postShift, index, shift; | |

FIXP_DBL ratio_m; | |

FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f); | |

preShift = CntLeadingZeros(b_m); | |

/* | |

Shift b into the range from 0..INV_TABLE_SIZE-1, | |

E.g. 10 bits must be skipped for INV_TABLE_BITS 8: | |

- leave 8 bits as index for table | |

- skip sign bit, | |

- skip first bit of mantissa, because this is always the same (>0.5) | |

We are dealing with energies, so we need not care | |

about negative numbers | |

*/ | |

/* | |

The first interval has half width so the lowest bit of the index is | |

needed for a doubled resolution. | |

*/ | |

shift = (DFRACT_BITS - 2 - INV_TABLE_BITS - preShift); | |

index = (shift < 0) ? (LONG)b_m << (-shift) : (LONG)b_m >> shift; | |

/* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */ | |

index &= (1 << (INV_TABLE_BITS + 1)) - 1; | |

/* Remove offset of half an interval */ | |

index--; | |

/* Now the lowest bit is shifted out */ | |

index = index >> 1; | |

/* Fetch inversed mantissa from table: */ | |

bInv_m = (index < 0) ? bInv_m : FDK_sbrDecoder_invTable[index]; | |

/* Multiply a with the inverse of b: */ | |

ratio_m = (index < 0) ? (a_m >> 1) : fMultDiv2(bInv_m, a_m); | |

postShift = CntLeadingZeros(ratio_m) - 1; | |

*ptrResult_m = ratio_m << postShift; | |

*ptrResult_e = a_e - b_e + 1 + preShift - postShift; | |

} | |

/*! | |

\brief Calculate the squareroot of a number given by mantissa and exponent | |

Mantissa is in fract format with values between 0 and 1. <br> | |

The base for the exponent is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br> | |

The operand is addressed via pointers and will be overwritten with the result. | |

For performance reasons, the square root is based on a table lookup | |

which limits accuracy. | |

*/ | |

static inline void FDK_sqrt_MantExp( | |

FIXP_DBL *mantissa, /*!< Pointer to mantissa */ | |

SCHAR *exponent, const SCHAR *destScale) { | |

FIXP_DBL input_m = *mantissa; | |

int input_e = (int)*exponent; | |

FIXP_DBL result = FL2FXCONST_DBL(0.0f); | |

int result_e = -FRACT_BITS; | |

/* Call lookup square root, which does internally normalization. */ | |

result = sqrtFixp_lookup(input_m, &input_e); | |

result_e = input_e; | |

/* Write result */ | |

if (exponent == destScale) { | |

*mantissa = result; | |

*exponent = result_e; | |

} else { | |

int shift = result_e - *destScale; | |

*mantissa = (shift >= 0) ? result << (INT)fixMin(DFRACT_BITS - 1, shift) | |

: result >> (INT)fixMin(DFRACT_BITS - 1, -shift); | |

*exponent = *destScale; | |

} | |

} | |

#endif |