#ifndef WH_FFT_H_1dbb6829_
#define WH_FFT_H_1dbb6829_

/*
 * This file was stolen from ffmpeg and modified for usability here.
 *  The original is
 * 
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This version is a derivative work of that version.  It is not free
 *  software; it is licensed under the GNU Lesser General Public
 *  License version 2.1, which places nontrivial restrictions on what
 *  may be done with it.  (I'm not terribly happy about that, but for
 *  my purposes accepting LGPL-infected code is a lower price than
 *  reimplementing it all myself.)
 *
 * The LGPL v2.1 as distributed with ffmpeg is in the accompanying file
 *  `LGPL-v2.1'.
 */

#include <stdint.h>

#include "config.h"

#ifndef CONFIG_FFT_FLOAT
#define CONFIG_FFT_FLOAT 1
#endif

#include "avutil-mem.h"

#if CONFIG_FFT_FLOAT

#include "avfft.h"

#define FFT_NAME(x) x

typedef float FFTDouble;

#else

#define FFT_NAME(x) x ## _fixed

typedef int16_t FFTSample;
typedef int     FFTDouble;

typedef struct FFTComplex {
    int16_t re, im;
} FFTComplex;

typedef struct FFTContext FFTContext;

#endif /* CONFIG_FFT_FLOAT */

typedef struct FFTDComplex {
    FFTDouble re, im;
} FFTDComplex;

/* FFT computation */

struct FFTContext {
    int nbits;
    int inverse;
    uint16_t *revtab;
    FFTComplex *tmp_buf;
    int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
    int mdct_bits; /* n = 2^nbits */
    /* pre/post rotation tables */
    FFTSample *tcos;
    FFTSample *tsin;
    /**
     * Do the permutation needed BEFORE calling fft_calc().
     */
    void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
    /**
     * Do a complex FFT with the parameters defined in ff_fft_init(). The
     * input data must be permuted before. No 1.0/sqrt(n) normalization is done.
     */
    void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
    void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
    void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
    void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
    void (*mdct_calcw)(struct FFTContext *s, FFTDouble *output, const FFTSample *input);
    int fft_permutation;
#define FF_FFT_PERM_DEFAULT   0
#define FF_FFT_PERM_SWAP_LSBS 1
#define FF_FFT_PERM_AVX       2
    int mdct_permutation;
#define FF_MDCT_PERM_NONE       0
#define FF_MDCT_PERM_INTERLEAVE 1
};

#if CONFIG_HARDCODED_TABLES
#define COSTABLE_CONST const
#else
#define COSTABLE_CONST
#endif

#define COSTABLE(size) \
    COSTABLE_CONST DECLARE_ALIGNED(32, FFTSample, FFT_NAME(ff_cos_##size))[size/2]

extern COSTABLE(16);
extern COSTABLE(32);
extern COSTABLE(64);
extern COSTABLE(128);
extern COSTABLE(256);
extern COSTABLE(512);
extern COSTABLE(1024);
extern COSTABLE(2048);
extern COSTABLE(4096);
extern COSTABLE(8192);
extern COSTABLE(16384);
extern COSTABLE(32768);
extern COSTABLE(65536);
extern COSTABLE_CONST FFTSample* const FFT_NAME(ff_cos_tabs)[17];

#define ff_init_ff_cos_tabs FFT_NAME(ff_init_ff_cos_tabs)

/**
 * Initialize the cosine table in ff_cos_tabs[index]
 * @param index index in ff_cos_tabs array of the table to initialize
 */
void ff_init_ff_cos_tabs(int index);

#define ff_fft_init FFT_NAME(ff_fft_init)
#define ff_fft_end  FFT_NAME(ff_fft_end)

/**
 * Set up a complex FFT.
 * @param nbits           log2 of the length of the input array
 * @param inverse         if 0 perform the forward transform, if 1 perform the inverse
 */
int ff_fft_init(FFTContext *s, int nbits, int inverse);

#if CONFIG_FFT_FLOAT
void ff_fft_init_altivec(FFTContext *s);
void ff_fft_init_mmx(FFTContext *s);
void ff_fft_init_arm(FFTContext *s);
#else
void ff_fft_fixed_init_arm(FFTContext *s);
#endif

void ff_fft_end(FFTContext *s);

#define ff_mdct_init FFT_NAME(ff_mdct_init)
#define ff_mdct_end  FFT_NAME(ff_mdct_end)

int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
void ff_mdct_end(FFTContext *s);

#endif