/* libFLAC - Free Lossless Audio Codec library

 * Copyright (C) 2006-2009  Josh Coalson

 * Copyright (C) 2011-2025  Xiph.Org Foundation

 *

 * 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 the Xiph.org Foundation 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 FOUNDATION 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.

 */

#ifdef HAVE_CONFIG_H

#  include <config.h>

#endif

#include <math.h>

#include "share/compat.h"

#include "FLAC/assert.h"

#include "FLAC/format.h"

#include "private/window.h"

#ifndef FLAC__INTEGER_ONLY_LIBRARY

#if defined(_MSC_VER)

// silence 25 MSVC warnings 'conversion from 'double' to 'float', possible loss of data'

#pragma warning ( disable : 4244 )

#endif

void FLAC__window_bartlett(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  if (L & 1) {

    for (n = 0; n <= N/2; n++)

      window[n] = 2.0f * n / (float)N;

    for (; n <= N; n++)

      window[n] = 2.0f - 2.0f * n / (float)N;

  }

  else {

    for (n = 0; n <= L/2-1; n++)

      window[n] = 2.0f * n / (float)N;

    for (; n <= N; n++)

      window[n] = 2.0f - 2.0f * n / (float)N;

  }

}

void FLAC__window_bartlett_hann(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = (FLAC__real)(0.62f - 0.48f * fabsf((float)n/(float)N-0.5f) - 0.38f * cosf(2.0f * M_PI * ((float)n/(float)N)));

}

void FLAC__window_blackman(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = (FLAC__real)(0.42f - 0.5f * cosf(2.0f * M_PI * n / N) + 0.08f * cosf(4.0f * M_PI * n / N));

}

/* 4-term -92dB side-lobe */

void FLAC__window_blackman_harris_4term_92db_sidelobe(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n <= N; n++)

    window[n] = (FLAC__real)(0.35875f - 0.48829f * cosf(2.0f * M_PI * n / N) + 0.14128f * cosf(4.0f * M_PI * n / N) - 0.01168f * cosf(6.0f * M_PI * n / N));

}

void FLAC__window_connes(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  const double N2 = (double)N / 2.;

  FLAC__int32 n;

  for (n = 0; n <= N; n++) {

    double k = ((double)n - N2) / N2;

    k = 1.0f - k * k;

    window[n] = (FLAC__real)(k * k);

  }

}

void FLAC__window_flattop(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = (FLAC__real)(0.21557895f - 0.41663158f * cosf(2.0f * M_PI * n / N) + 0.277263158f * cosf(4.0f * M_PI * n / N) - 0.083578947f * cosf(6.0f * M_PI * n / N) + 0.006947368f * cosf(8.0f * M_PI * n / N));

}

void FLAC__window_gauss(FLAC__real *window, const FLAC__int32 L, const FLAC__real stddev)

{

  const FLAC__int32 N = L - 1;

  const double N2 = (double)N / 2.;

  FLAC__int32 n;

  if(!(stddev > 0.0f && stddev <= 0.5f))

    /* stddev is not between 0 and 0.5, might be NaN.

     * Default to 0.5 */

    FLAC__window_gauss(window, L, 0.25f);

  else {

    for (n = 0; n <= N; n++) {

      const double k = ((double)n - N2) / (stddev * N2);

      window[n] = (FLAC__real)exp(-0.5f * k * k);

    }

  }

}

void FLAC__window_hamming(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = (FLAC__real)(0.54f - 0.46f * cosf(2.0f * M_PI * n / N));

}

void FLAC__window_hann(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = (FLAC__real)(0.5f - 0.5f * cosf(2.0f * M_PI * n / N));

}

void FLAC__window_kaiser_bessel(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = (FLAC__real)(0.402f - 0.498f * cosf(2.0f * M_PI * n / N) + 0.098f * cosf(4.0f * M_PI * n / N) - 0.001f * cosf(6.0f * M_PI * n / N));

}

void FLAC__window_nuttall(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = (FLAC__real)(0.3635819f - 0.4891775f*cosf(2.0f*M_PI*n/N) + 0.1365995f*cosf(4.0f*M_PI*n/N) - 0.0106411f*cosf(6.0f*M_PI*n/N));

}

void FLAC__window_rectangle(FLAC__real *window, const FLAC__int32 L)

{

  FLAC__int32 n;

  for (n = 0; n < L; n++)

    window[n] = 1.0f;

}

void FLAC__window_triangle(FLAC__real *window, const FLAC__int32 L)

{

  FLAC__int32 n;

  if (L & 1) {

    for (n = 1; n <= (L+1)/2; n++)

      window[n-1] = 2.0f * n / ((float)L + 1.0f);

    for (; n <= L; n++)

      window[n-1] = (float)(2 * (L - n + 1)) / ((float)L + 1.0f);

  }

  else {

    for (n = 1; n <= L/2; n++)

      window[n-1] = 2.0f * n / ((float)L + 1.0f);

    for (; n <= L; n++)

      window[n-1] = (float)(2 * (L - n + 1)) / ((float)L + 1.0f);

  }

}

void FLAC__window_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p)

{

  if (p <= 0.0)

    FLAC__window_rectangle(window, L);

  else if (p >= 1.0)

    FLAC__window_hann(window, L);

  else if (!(p > 0.0f && p < 1.0f))

    /* p is not between 0 and 1, probably NaN.

     * Default to 0.5 */

    FLAC__window_tukey(window, L, 0.5f);

  else {

    const FLAC__int32 Np = (FLAC__int32)(p / 2.0f * L) - 1;

    FLAC__int32 n;

    /* start with rectangle... */

    FLAC__window_rectangle(window, L);

    /* ...replace ends with hann */

    if (Np > 0) {

      for (n = 0; n <= Np; n++) {

        window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * n / Np));

        window[L-Np-1+n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * (n+Np) / Np));

      }

    }

  }

}

void FLAC__window_partial_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p, const FLAC__real start, const FLAC__real end)

{

  const FLAC__int32 start_n = (FLAC__int32)(start * L);

  const FLAC__int32 end_n = (FLAC__int32)(end * L);

  const FLAC__int32 N = end_n - start_n;

  FLAC__int32 Np, n, i;

  if (p <= 0.0f)

    FLAC__window_partial_tukey(window, L, 0.05f, start, end);

  else if (p >= 1.0f)

    FLAC__window_partial_tukey(window, L, 0.95f, start, end);

  else if (!(p > 0.0f && p < 1.0f))

    /* p is not between 0 and 1, probably NaN.

     * Default to 0.5 */

    FLAC__window_partial_tukey(window, L, 0.5f, start, end);

  else {

    Np = (FLAC__int32)(p / 2.0f * N);

    for (n = 0; n < start_n && n < L; n++)

      window[n] = 0.0f;

    for (i = 1; n < (start_n+Np) && n < L; n++, i++)

      window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Np));

    for (; n < (end_n-Np) && n < L; n++)

      window[n] = 1.0f;

    for (i = Np; n < end_n && n < L; n++, i--)

      window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Np));

    for (; n < L; n++)

      window[n] = 0.0f;

  }

}

void FLAC__window_punchout_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p, const FLAC__real start, const FLAC__real end)

{

  const FLAC__int32 start_n = (FLAC__int32)(start * L);

  const FLAC__int32 end_n = (FLAC__int32)(end * L);

  FLAC__int32 Ns, Ne, n, i;

  if (p <= 0.0f)

    FLAC__window_punchout_tukey(window, L, 0.05f, start, end);

  else if (p >= 1.0f)

    FLAC__window_punchout_tukey(window, L, 0.95f, start, end);

  else if (!(p > 0.0f && p < 1.0f))

    /* p is not between 0 and 1, probably NaN.

     * Default to 0.5 */

    FLAC__window_punchout_tukey(window, L, 0.5f, start, end);

  else {

    Ns = (FLAC__int32)(p / 2.0f * start_n);

    Ne = (FLAC__int32)(p / 2.0f * (L - end_n));

    for (n = 0, i = 1; n < Ns && n < L; n++, i++)

      window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ns));

    for (; n < start_n-Ns && n < L; n++)

      window[n] = 1.0f;

    for (i = Ns; n < start_n && n < L; n++, i--)

      window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ns));

    for (; n < end_n && n < L; n++)

      window[n] = 0.0f;

    for (i = 1; n < end_n+Ne && n < L; n++, i++)

      window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ne));

    for (; n < L - (Ne) && n < L; n++)

      window[n] = 1.0f;

    for (i = Ne; n < L; n++, i--)

      window[n] = (FLAC__real)(0.5f - 0.5f * cosf(M_PI * i / Ne));

  }

}

void FLAC__window_welch(FLAC__real *window, const FLAC__int32 L)

{

  const FLAC__int32 N = L - 1;

  const double N2 = (double)N / 2.;

  FLAC__int32 n;

  for (n = 0; n <= N; n++) {

    const double k = ((double)n - N2) / N2;

    window[n] = (FLAC__real)(1.0f - k * k);

  }

}

#if defined(_MSC_VER)

#pragma warning ( default : 4244 )

#endif

#endif /* !defined FLAC__INTEGER_ONLY_LIBRARY */