/*

 * 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 <stdint.h>

#include "config.h"

#include "libavutil/attributes.h"

#include "mathops.h"

#include "huffyuv.h"

#include "huffyuvdsp.h"

// 0x00010001 or 0x0001000100010001 or whatever, depending on the cpu's native arithmetic size

#define pw_1 (ULONG_MAX / UINT16_MAX)

static void add_int16_c(uint16_t *dst, const uint16_t *src, unsigned mask, int w){

    long i;

    unsigned long pw_lsb = (mask >> 1) * pw_1;

    unsigned long pw_msb = pw_lsb +  pw_1;

    for (i = 0; i <= w - (int)sizeof(long)/2; i += sizeof(long)/2) {

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

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

        *(long*)(dst+i) = ((a&pw_lsb) + (b&pw_lsb)) ^ ((a^b)&pw_msb);

    }

    for(; i<w; i++)

        dst[i] = (dst[i] + src[i]) & mask;

}

static void add_hfyu_median_pred_int16_c(uint16_t *dst, const uint16_t *src, const uint16_t *diff, unsigned mask, int w, int *left, int *left_top){

    int i;

    uint16_t l, lt;

    l  = *left;

    lt = *left_top;

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

        l  = (mid_pred(l, src[i], (l + src[i] - lt) & mask) + diff[i]) & mask;

        lt = src[i];

        dst[i] = l;

    }

    *left     = l;

    *left_top = lt;

}

static void add_hfyu_left_pred_bgr32_c(uint8_t *dst, const uint8_t *src,

                                       intptr_t w, uint8_t *left)

{

    int i;

    uint8_t r = left[R], g = left[G], b = left[B], a = left[A];

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

        b += src[4 * i + B];

        g += src[4 * i + G];

        r += src[4 * i + R];

        a += src[4 * i + A];

        dst[4 * i + B] = b;

        dst[4 * i + G] = g;

        dst[4 * i + R] = r;

        dst[4 * i + A] = a;

    }

    left[B] = b;

    left[G] = g;

    left[R] = r;

    left[A] = a;

}

av_cold void ff_huffyuvdsp_init(HuffYUVDSPContext *c, enum AVPixelFormat pix_fmt)

{

    c->add_int16 = add_int16_c;

    c->add_hfyu_median_pred_int16 = add_hfyu_median_pred_int16_c;

    c->add_hfyu_left_pred_bgr32 = add_hfyu_left_pred_bgr32_c;

#if ARCH_RISCV

    ff_huffyuvdsp_init_riscv(c, pix_fmt);

#elif ARCH_X86

    ff_huffyuvdsp_init_x86(c, pix_fmt);

#endif

}