/*

 * AC-3 DSP functions

 * Copyright (c) 2011 Justin Ruggles

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <math.h>

#include <stdlib.h>

#include <string.h>

#include "config.h"

#include "libavutil/attributes.h"

#include "libavutil/common.h"

#include "libavutil/intmath.h"

#include "libavutil/mem_internal.h"

#include "ac3defs.h"

#include "ac3dsp.h"

#include "ac3tab.h"

#include "mathops.h"

static void ac3_exponent_min_c(uint8_t *exp, int num_reuse_blocks, int nb_coefs)

{

    int blk, i;

    if (!num_reuse_blocks)

        return;

    for (i = 0; i < nb_coefs; i++) {

        uint8_t min_exp = *exp;

        uint8_t *exp1 = exp + 256;

        for (blk = 0; blk < num_reuse_blocks; blk++) {

            uint8_t next_exp = *exp1;

            if (next_exp < min_exp)

                min_exp = next_exp;

            exp1 += 256;

        }

        *exp++ = min_exp;

    }

}

static void float_to_fixed24_c(int32_t *dst, const float *src, size_t len)

{

    const float scale = 1 << 24;

    do {

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        len -= 8;

    } while (len > 0);

}

static void ac3_bit_alloc_calc_bap_c(int16_t *mask, int16_t *psd,

                                     int start, int end,

                                     int snr_offset, int floor,

                                     const uint8_t *bap_tab, uint8_t *bap)

{

    int bin, band, band_end;

    /* special case, if snr offset is -960, set all bap's to zero */

    if (snr_offset == -960) {

        memset(bap, 0, AC3_MAX_COEFS);

        return;

    }

    bin  = start;

    band = ff_ac3_bin_to_band_tab[start];

    do {

        int m = (FFMAX(mask[band] - snr_offset - floor, 0) & 0x1FE0) + floor;

        band_end = ff_ac3_band_start_tab[++band];

        band_end = FFMIN(band_end, end);

        for (; bin < band_end; bin++) {

            int address = av_clip_uintp2((psd[bin] - m) >> 5, 6);

            bap[bin] = bap_tab[address];

        }

    } while (end > band_end);

}

static void ac3_update_bap_counts_c(uint16_t mant_cnt[16], uint8_t *bap,

                                    int len)

{

    while (len-- > 0)

        mant_cnt[bap[len]]++;

}

DECLARE_ALIGNED(16, const uint16_t, ff_ac3_bap_bits)[16] = {

    0,  0,  0,  3,  0,  4,  5,  6,  7,  8,  9, 10, 11, 12, 14, 16

};

static int ac3_compute_mantissa_size_c(uint16_t mant_cnt[6][16])

{

    int blk, bap;

    int bits = 0;

    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {

        // bap=1 : 3 mantissas in 5 bits

        bits += (mant_cnt[blk][1] / 3) * 5;

        // bap=2 : 3 mantissas in 7 bits

        // bap=4 : 2 mantissas in 7 bits

        bits += ((mant_cnt[blk][2] / 3) + (mant_cnt[blk][4] >> 1)) * 7;

        // bap=3 : 1 mantissa in 3 bits

        bits += mant_cnt[blk][3] * 3;

        // bap=5 to 15 : get bits per mantissa from table

        for (bap = 5; bap < 16; bap++)

            bits += mant_cnt[blk][bap] * ff_ac3_bap_bits[bap];

    }

    return bits;

}

static void ac3_extract_exponents_c(uint8_t *exp, int32_t *coef, int nb_coefs)

{

    int i;

    for (i = 0; i < nb_coefs; i++) {

        int v = abs(coef[i]);

        exp[i] = v ? 23 - av_log2(v) : 24;

    }

}

static void ac3_sum_square_butterfly_int32_c(int64_t sum[4],

                                             const int32_t *coef0,

                                             const int32_t *coef1,

                                             int len)

{

    int i;

    sum[0] = sum[1] = sum[2] = sum[3] = 0;

    for (i = 0; i < len; i++) {

        int lt = coef0[i];

        int rt = coef1[i];

        int md = lt + rt;

        int sd = lt - rt;

        MAC64(sum[0], lt, lt);

        MAC64(sum[1], rt, rt);

        MAC64(sum[2], md, md);

        MAC64(sum[3], sd, sd);

    }

}

static void ac3_sum_square_butterfly_float_c(float sum[4],

                                             const float *coef0,

                                             const float *coef1,

                                             int len)

{

    int i;

    sum[0] = sum[1] = sum[2] = sum[3] = 0;

    for (i = 0; i < len; i++) {

        float lt = coef0[i];

        float rt = coef1[i];

        float md = lt + rt;

        float sd = lt - rt;

        sum[0] += lt * lt;

        sum[1] += rt * rt;

        sum[2] += md * md;

        sum[3] += sd * sd;

    }

}

static void ac3_downmix_5_to_2_symmetric_c(float **samples, float **matrix,

                                           int len)

{

    int i;

    float v0, v1;

    float front_mix    = matrix[0][0];

    float center_mix   = matrix[0][1];

    float surround_mix = matrix[0][3];

    for (i = 0; i < len; i++) {

        v0 = samples[0][i] * front_mix  +

             samples[1][i] * center_mix +

             samples[3][i] * surround_mix;

        v1 = samples[1][i] * center_mix +

             samples[2][i] * front_mix  +

             samples[4][i] * surround_mix;

        samples[0][i] = v0;

        samples[1][i] = v1;

    }

}

static void ac3_downmix_5_to_1_symmetric_c(float **samples, float **matrix,

                                           int len)

{

    int i;

    float front_mix    = matrix[0][0];

    float center_mix   = matrix[0][1];

    float surround_mix = matrix[0][3];

    for (i = 0; i < len; i++) {

        samples[0][i] = samples[0][i] * front_mix    +

                        samples[1][i] * center_mix   +

                        samples[2][i] * front_mix    +

                        samples[3][i] * surround_mix +

                        samples[4][i] * surround_mix;

    }

}

static void ac3_downmix_c(float **samples, float **matrix,

                          int out_ch, int in_ch, int len)

{

    int i, j;

    float v0, v1;

    if (out_ch == 2) {

        for (i = 0; i < len; i++) {

            v0 = v1 = 0.0f;

            for (j = 0; j < in_ch; j++) {

                v0 += samples[j][i] * matrix[0][j];

                v1 += samples[j][i] * matrix[1][j];

            }

            samples[0][i] = v0;

            samples[1][i] = v1;

        }

    } else if (out_ch == 1) {

        for (i = 0; i < len; i++) {

            v0 = 0.0f;

            for (j = 0; j < in_ch; j++)

                v0 += samples[j][i] * matrix[0][j];

            samples[0][i] = v0;

        }

    }

}

static void ac3_downmix_5_to_2_symmetric_c_fixed(int32_t **samples, int16_t **matrix,

                                           int len)

{

    int i;

    int64_t v0, v1;

    int16_t front_mix    = matrix[0][0];

    int16_t center_mix   = matrix[0][1];

    int16_t surround_mix = matrix[0][3];

    for (i = 0; i < len; i++) {

        v0 = (int64_t)samples[0][i] * front_mix  +

             (int64_t)samples[1][i] * center_mix +

             (int64_t)samples[3][i] * surround_mix;

        v1 = (int64_t)samples[1][i] * center_mix +

             (int64_t)samples[2][i] * front_mix  +

             (int64_t)samples[4][i] * surround_mix;

        samples[0][i] = (v0+2048)>>12;

        samples[1][i] = (v1+2048)>>12;

    }

}

static void ac3_downmix_5_to_1_symmetric_c_fixed(int32_t **samples, int16_t **matrix,

                                                 int len)

{

    int i;

    int64_t v0;

    int16_t front_mix    = matrix[0][0];

    int16_t center_mix   = matrix[0][1];

    int16_t surround_mix = matrix[0][3];

    for (i = 0; i < len; i++) {

        v0 = (int64_t)samples[0][i] * front_mix    +

             (int64_t)samples[1][i] * center_mix   +

             (int64_t)samples[2][i] * front_mix    +

             (int64_t)samples[3][i] * surround_mix +

             (int64_t)samples[4][i] * surround_mix;

        samples[0][i] = (v0+2048)>>12;

    }

}

static void ac3_downmix_c_fixed(int32_t **samples, int16_t **matrix,

                                int out_ch, int in_ch, int len)

{

    int i, j;

    int64_t v0, v1;

    if (out_ch == 2) {

        for (i = 0; i < len; i++) {

            v0 = v1 = 0;

            for (j = 0; j < in_ch; j++) {

                v0 += (int64_t)samples[j][i] * matrix[0][j];

                v1 += (int64_t)samples[j][i] * matrix[1][j];

            }

            samples[0][i] = (v0+2048)>>12;

            samples[1][i] = (v1+2048)>>12;

        }

    } else if (out_ch == 1) {

        for (i = 0; i < len; i++) {

            v0 = 0;

            for (j = 0; j < in_ch; j++)

                v0 += (int64_t)samples[j][i] * matrix[0][j];

            samples[0][i] = (v0+2048)>>12;

        }

    }

}

void ff_ac3dsp_downmix_fixed(AC3DSPContext *c, int32_t **samples, int16_t **matrix,

                             int out_ch, int in_ch, int len)

{

    if (c->in_channels != in_ch || c->out_channels != out_ch) {

        c->in_channels  = in_ch;

        c->out_channels = out_ch;

        c->downmix_fixed = NULL;

        if (in_ch == 5 && out_ch == 2 &&

            !(matrix[1][0] | matrix[0][2]  |

              matrix[1][3] | matrix[0][4]  |

             (matrix[0][1] ^ matrix[1][1]) |

             (matrix[0][0] ^ matrix[1][2]))) {

            c->downmix_fixed = ac3_downmix_5_to_2_symmetric_c_fixed;

        } else if (in_ch == 5 && out_ch == 1 &&

                   matrix[0][0] == matrix[0][2] &&

                   matrix[0][3] == matrix[0][4]) {

            c->downmix_fixed = ac3_downmix_5_to_1_symmetric_c_fixed;

        }

    }

    if (c->downmix_fixed)

        c->downmix_fixed(samples, matrix, len);

    else

        ac3_downmix_c_fixed(samples, matrix, out_ch, in_ch, len);

}

void ff_ac3dsp_downmix(AC3DSPContext *c, float **samples, float **matrix,

                       int out_ch, int in_ch, int len)

{

    if (c->in_channels != in_ch || c->out_channels != out_ch) {

        int **matrix_cmp = (int **)matrix;

        c->in_channels  = in_ch;

        c->out_channels = out_ch;

        c->downmix      = NULL;

        if (in_ch == 5 && out_ch == 2 &&

            !(matrix_cmp[1][0] | matrix_cmp[0][2]   |

              matrix_cmp[1][3] | matrix_cmp[0][4]   |

             (matrix_cmp[0][1] ^ matrix_cmp[1][1]) |

             (matrix_cmp[0][0] ^ matrix_cmp[1][2]))) {

            c->downmix = ac3_downmix_5_to_2_symmetric_c;

        } else if (in_ch == 5 && out_ch == 1 &&

                   matrix_cmp[0][0] == matrix_cmp[0][2] &&

                   matrix_cmp[0][3] == matrix_cmp[0][4]) {

            c->downmix = ac3_downmix_5_to_1_symmetric_c;

        }

#if ARCH_X86 && HAVE_X86ASM

        ff_ac3dsp_set_downmix_x86(c);

#endif

    }

    if (c->downmix)

        c->downmix(samples, matrix, len);

    else

        ac3_downmix_c(samples, matrix, out_ch, in_ch, len);

}

av_cold void ff_ac3dsp_init(AC3DSPContext *c)

{

    c->ac3_exponent_min = ac3_exponent_min_c;

    c->float_to_fixed24 = float_to_fixed24_c;

    c->bit_alloc_calc_bap = ac3_bit_alloc_calc_bap_c;

    c->update_bap_counts = ac3_update_bap_counts_c;

    c->compute_mantissa_size = ac3_compute_mantissa_size_c;

    c->extract_exponents = ac3_extract_exponents_c;

    c->sum_square_butterfly_int32 = ac3_sum_square_butterfly_int32_c;

    c->sum_square_butterfly_float = ac3_sum_square_butterfly_float_c;

    c->in_channels           = 0;

    c->out_channels          = 0;

    c->downmix               = NULL;

    c->downmix_fixed         = NULL;

#if ARCH_AARCH64

    ff_ac3dsp_init_aarch64(c);

#elif ARCH_ARM

    ff_ac3dsp_init_arm(c);

#elif ARCH_X86 && HAVE_X86ASM

    ff_ac3dsp_init_x86(c);

#elif ARCH_MIPS

    ff_ac3dsp_init_mips(c);

#elif ARCH_RISCV

    ff_ac3dsp_init_riscv(c);

#endif

}