/*

 * Lossless video DSP utils

 *

 * 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 "config.h"

#include "lossless_videodsp.h"

#include "libavcodec/mathops.h"

// 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size

#define pb_7f (~0UL / 255 * 0x7f)

#define pb_80 (~0UL / 255 * 0x80)

static void add_bytes_c(uint8_t *dst, uint8_t *src, ptrdiff_t w)

{

    long i;

    for (i = 0; i <= w - (int) sizeof(long); i += sizeof(long)) {

        long a = *(long *) (src + i);

        long b = *(long *) (dst + i);

        *(long *) (dst + i) = ((a & pb_7f) + (b & pb_7f)) ^ ((a ^ b) & pb_80);

    }

    for (; i < w; i++)

        dst[i + 0] += src[i + 0];

}

static void add_median_pred_c(uint8_t *dst, const uint8_t *src1,

                              const uint8_t *diff, ptrdiff_t w,

                              int *left, int *left_top)

{

    int i;

    uint8_t l, lt;

    l  = *left;

    lt = *left_top;

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

        l      = mid_pred(l, src1[i], (l + src1[i] - lt) & 0xFF) + diff[i];

        lt     = src1[i];

        dst[i] = l;

    }

    *left     = l;

    *left_top = lt;

}

static int add_left_pred_c(uint8_t *dst, const uint8_t *src, ptrdiff_t w,

                           int acc)

{

    int i;

    for (i = 0; i < w - 1; i++) {

        acc   += src[i];

        dst[i] = acc;

        i++;

        acc   += src[i];

        dst[i] = acc;

    }

    for (; i < w; i++) {

        acc   += src[i];

        dst[i] = acc;

    }

    return acc;

}

static int add_left_pred_int16_c(uint16_t *dst, const uint16_t *src, unsigned mask, ptrdiff_t w, unsigned acc){

    int i;

    for(i=0; i<w-1; i++){

        acc+= src[i];

        dst[i]= acc &= mask;

        i++;

        acc+= src[i];

        dst[i]= acc &= mask;

    }

    for(; i<w; i++){

        acc+= src[i];

        dst[i]= acc &= mask;

    }

    return acc;

}

static void add_gradient_pred_c(uint8_t *src, const ptrdiff_t stride, const ptrdiff_t width){

    int A, B, C, i;

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

        A = src[i - stride];

        B = src[i - (stride + 1)];

        C = src[i - 1];

        src[i] = (A - B + C + src[i]) & 0xFF;

    }

}

void ff_llviddsp_init(LLVidDSPContext *c)

{

    c->add_bytes                  = add_bytes_c;

    c->add_median_pred            = add_median_pred_c;

    c->add_left_pred              = add_left_pred_c;

    c->add_left_pred_int16        = add_left_pred_int16_c;

    c->add_gradient_pred          = add_gradient_pred_c;

#if ARCH_PPC

    ff_llviddsp_init_ppc(c);

#elif ARCH_RISCV

    ff_llviddsp_init_riscv(c);

#elif ARCH_X86

    ff_llviddsp_init_x86(c);

#endif

}