/**

 * Copyright (C) 2026 Niklas Haas

 *

 * 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 <stdbool.h>

#include "libavutil/avassert.h"

#include "libavutil/mem.h"

#include "libavutil/refstruct.h"

#include "ops.h"

#include "uops.h"

#include "uops_list.h"

int ff_sws_uop_cmp(const SwsUOp *a, const SwsUOp *b)

{

    if (a->type != b->type)

        return (int) a->type - b->type;

    if (a->uop != b->uop)

        return (int) a->uop - b->uop;

    if (a->mask != b->mask)

        return (int) a->mask - b->mask;

    return memcmp(&a->par, &b->par, sizeof(a->par));

}

static const struct {

    char abbr[32];

} uop_names[SWS_UOP_TYPE_NB] = {

#define UOP_NAME(OP, ABBR) [OP] = { ABBR },

    UOPS_LIST(UOP_NAME)

#undef UOP_NAME

};

void ff_sws_uop_name(const SwsUOp *op, char buf[SWS_UOP_NAME_MAX])

{

    AVBPrint bp;

    av_bprint_init_for_buffer(&bp, buf, SWS_UOP_NAME_MAX);

    if (op->type != SWS_PIXEL_NONE)

        av_bprintf(&bp, "%s_", ff_sws_pixel_type_name(op->type));

    av_bprintf(&bp, "%s", uop_names[op->uop].abbr);

    if (op->mask)

        av_bprintf(&bp, "_%s", ff_sws_comp_mask_str(op->mask));

    const SwsUOpParams *par = &op->par;

    switch (op->uop) {

    case SWS_UOP_READ_PLANAR_FH:

    case SWS_UOP_READ_PLANAR_FV:

    case SWS_UOP_READ_PLANAR_FV_FMA:

        av_bprintf(&bp, "_%s", ff_sws_pixel_type_name(par->filter.type));

        break;

    case SWS_UOP_RW_SHUFFLE:

        av_bprintf(&bp, "_%x_%u_%u", par->shuffle.clear_value,

                   par->shuffle.read_size, par->shuffle.write_size);

        break;

    case SWS_UOP_LSHIFT:

    case SWS_UOP_RSHIFT:

        av_bprintf(&bp, "_%u", par->shift.amount);

        break;

    case SWS_UOP_PERMUTE:

    case SWS_UOP_COPY:

        av_bprint_chars(&bp, '_', 1);

        for (int i = 0; i < par->move.num_moves; i++)

            av_bprint_chars(&bp, "txyzw"[par->move.dst[i] + 1], 1);

        av_bprint_chars(&bp, '_', 1);

        for (int i = 0; i < par->move.num_moves; i++)

            av_bprint_chars(&bp, "txyzw"[par->move.src[i] + 1], 1);

        break;

    case SWS_UOP_PACK:

    case SWS_UOP_UNPACK:

        av_bprint_chars(&bp, '_', 1);

        for (int i = 0; i < 4 && par->pack.pattern[i]; i++)

            av_bprintf(&bp, "%x", par->pack.pattern[i]);

        break;

    case SWS_UOP_CLEAR:

        av_bprint_chars(&bp, '_', 1);

        for (int i = 0; i < 4; i++) {

            if (!SWS_COMP_TEST(op->mask, i))

                continue;

            else if (SWS_COMP_TEST(par->clear.one, i))

                av_bprint_chars(&bp, '1', 1);

            else if (SWS_COMP_TEST(par->clear.zero, i))

                av_bprint_chars(&bp, '0', 1);

            else

                av_bprint_chars(&bp, 'x', 1);

        }

        break;

    case SWS_UOP_LINEAR:

    case SWS_UOP_LINEAR_FMA:

        for (int i = 0; i < 4; i++) {

            if (!SWS_COMP_TEST(op->mask, i))

                continue;

            av_bprint_chars(&bp, '_', 1);

            for (int j = 0; j < 5; j++) {

                if (par->lin.one & SWS_MASK(i, j))

                    av_bprint_chars(&bp, '1', 1);

                else if (par->lin.zero & SWS_MASK(i, j))

                    av_bprint_chars(&bp, '0', 1);

                else if (par->lin.exact & SWS_MASK(i, j))

                    av_bprint_chars(&bp, 'X', 1);

                else

                    av_bprint_chars(&bp, 'x', 1);

            }

        }

        break;

    case SWS_UOP_DITHER:

        for (int i = 0; i < 4; i++) {

            if (SWS_COMP_TEST(op->mask, i))

                av_bprintf(&bp, "_%d", par->dither.y_offset[i]);

        }

        const unsigned size = 1u << par->dither.size_log2;

        av_bprintf(&bp, "_%ux%u", size, size);

        break;

    case SWS_UOP_LUT_3D:

        av_bprintf(&bp, "_%s", par->lut3d.dynamic ? "dynamic" : "static");

        break;

    }

    av_assert0(av_bprint_is_complete(&bp));

}

static void uop_uninit(SwsUOp *uop)

{

    switch (uop->uop) {

    case SWS_UOP_DITHER:

        av_refstruct_unref(&uop->data.ptr);

        break;

    case SWS_UOP_READ_PLANAR_FH:

    case SWS_UOP_READ_PLANAR_FV:

    case SWS_UOP_READ_PLANAR_FV_FMA:

        av_refstruct_unref(&uop->data.kernel);

        break;

    case SWS_UOP_LUT_3D:

        av_refstruct_unref(&uop->data.lut3d);

        break;

    }

    *uop = (SwsUOp) {0};

}

void ff_sws_uop_list_free(SwsUOpList **p_ops)

{

    SwsUOpList *ops = *p_ops;

    if (!ops)

        return;

    for (int i = 0; i < ops->num_ops; i++)

        uop_uninit(&ops->ops[i]);

    av_freep(&ops->ops);

    av_free(ops);

    *p_ops = NULL;

}

SwsUOpList *ff_sws_uop_list_alloc(void)

{

    return av_mallocz(sizeof(SwsUOpList));

}

int ff_sws_uop_list_append(SwsUOpList *uops, SwsUOp *uop)

{

    if (!av_dynarray2_add((void **) &uops->ops, &uops->num_ops,

                          sizeof(*uop), (uint8_t *) uop))

    {

        uop_uninit(uop);

        return AVERROR(ENOMEM);

    }

    *uop = (SwsUOp) {0};

    return 0;

}

void ff_sws_uop_list_remove_at(SwsUOpList *uops, int index, int count)

{

    const int end = uops->num_ops - count;

    av_assert2(index >= 0 && count >= 0 && index + count <= uops->num_ops);

    for (int i = 0; i < count; i++)

        uop_uninit(&uops->ops[index + i]);

    for (int i = index; i < end; i++)

        uops->ops[i] = uops->ops[i + count];

    uops->num_ops = end;

}

int ff_sws_dither_height(const SwsDitherUOp *dither)

{

    int max_offset = 0;

    for (int i = 0; i < 4; i++)

        max_offset = FFMAX(max_offset, dither->y_offset[i]);

    return (1 << dither->size_log2) + max_offset;

}

/* Conditionally promotes a pixel type to integer only if allowed by the flags */

static SwsPixelType pixel_type_to_int(SwsUOpFlags flags, const SwsPixelType type)

{

    if (!(flags & SWS_UOP_FLAG_PUNNING))

        return type;

    switch (ff_sws_pixel_type_size(type)) {

    case 1: return SWS_PIXEL_U8;

    case 2: return SWS_PIXEL_U16;

    case 4: return SWS_PIXEL_U32;

    default: break;

    }

    av_unreachable("Invalid pixel type!");

    return SWS_PIXEL_NONE;

}

static bool exact_product_f32(float a, float b)

{

    volatile float prod   = a * b;

    volatile float result = b ? prod / b : 0.0f;

    return !b || result == a;

}

static bool exact_prod(SwsPixel coef, const SwsOpPad *input)

{

    if (ff_sws_pixel_type_is_int(input->type))

        return true;

    else if (!input->min.den || !input->max.den)

        return false; /* unknown bounds */

    const SwsPixel min = ff_sws_pixel_from_q64(input->type, input->min);

    const SwsPixel max = ff_sws_pixel_from_q64(input->type, input->max);

    switch (input->type) {

    case SWS_PIXEL_F32:

        return exact_product_f32(coef.f32, min.f32) &&

               exact_product_f32(coef.f32, max.f32);

    }

    av_unreachable("Invalid pixel type!");

    return false;

}

static bool check_filter_fma(SwsContext *ctx, SwsUOpFlags flags, const SwsOp *op)

{

    if (!(flags & SWS_UOP_FLAG_FMA))

        return false;

    if (!(ctx->flags & SWS_BITEXACT))

        return true;

    if (!ff_sws_pixel_type_is_int(op->rw.type))

        return false;

    const int bits = ff_sws_pixel_type_size(op->rw.type) * 8;

    const uint64_t max_val = UINT64_MAX >> (64 - bits);

    /* Maximum value representable losslessly as float. Note that this is

     * currently true only for U8, but that may change if we ever update the

     * value of SWS_FILTER_SCALE. */

    return max_val * SWS_FILTER_SCALE <= (1 << 22);

}

static int translate_rw_op(SwsContext *ctx, SwsUOpList *ops, SwsUOpFlags flags,

                           const SwsOp *op)

{

    SwsUOp uop = {

        .type = op->rw.type,

        .mask = SWS_COMP_MASK(op->rw.elems > 0, op->rw.elems > 1,

                              op->rw.elems > 2, op->rw.elems > 3),

    };

    /* Non-filtered reads don't care about the exact pixel contents */

    if (!op->rw.filter.op)

        uop.type = pixel_type_to_int(flags, op->rw.type);

    const bool is_read = op->op == SWS_OP_READ;

    if (op->rw.filter.op) {

        if (op->op == SWS_OP_WRITE || op->rw.frac || op->rw.mode != SWS_RW_PLANAR)

            return AVERROR(ENOTSUP);

        uop.par.filter.type = op->rw.filter.type;

        uop.data.kernel = av_refstruct_ref(op->rw.filter.kernel);

        if (op->rw.filter.op == SWS_OP_FILTER_H) {

            uop.uop = SWS_UOP_READ_PLANAR_FH;

        } else if (check_filter_fma(ctx, flags, op)) {

            uop.uop = SWS_UOP_READ_PLANAR_FV_FMA;

        } else {

            uop.uop = SWS_UOP_READ_PLANAR_FV;

        }

    } else if (op->rw.mode == SWS_RW_PACKED && op->rw.elems > 1) {

        if (op->rw.frac)

            return AVERROR(ENOTSUP);

        uop.uop = is_read ? SWS_UOP_READ_PACKED : SWS_UOP_WRITE_PACKED;

    } else if (op->rw.mode == SWS_RW_PALETTE) {

        if (!(flags & SWS_UOP_FLAG_READ_PALETTE) || op->rw.frac || !is_read)

            return AVERROR(ENOTSUP);

        uop.uop = SWS_UOP_READ_PALETTE;

    } else if (op->rw.frac == 3) {

        uop.uop = is_read ? SWS_UOP_READ_BIT : SWS_UOP_WRITE_BIT;

    } else if (op->rw.frac == 1) {

        uop.uop = is_read ? SWS_UOP_READ_NIBBLE : SWS_UOP_WRITE_NIBBLE;

    } else {

        av_assert0(!op->rw.frac);

        uop.uop = is_read ? SWS_UOP_READ_PLANAR : SWS_UOP_WRITE_PLANAR;

    }

    const int planes = ff_sws_rw_op_planes(op);

    if (op->op == SWS_OP_READ) {

        ops->planes_in  |= SWS_COMP_ELEMS(planes);

    } else {

        ops->planes_out |= SWS_COMP_ELEMS(planes);

    }

    return ff_sws_uop_list_append(ops, &uop);

}

static int count_idx(const int *arr, size_t size, int val)

{

    int num = 0;

    for (size_t i = 0; i < size; i++) {

        if (arr[i] == val)

            num++;

    }

    return num;

}

static int translate_swizzle(SwsUOpList *ops, SwsUOpFlags flags, const SwsOp *op)

{

    SwsUOp uop = {

        .uop  = SWS_UOP_PERMUTE,

        .type = pixel_type_to_int(flags, ff_sws_op_input_type(op)),

        .mask = ff_sws_comp_mask_needed(op),

    };

    SwsMoveUOp *par = &uop.par.move;

    /* Mask of components that are not yet satisfied */

    SwsCompMask todo = uop.mask;

    for (int i = 0; i < 4; i++) {

        if (op->swizzle.in[i] == i)

            todo &= ~SWS_COMP(i);

    }

    /* Mask of components whose value is required for the final output */

    SwsCompMask needed = 0;

    for (int i = 0; i < 4; i++) {

        if (SWS_OP_NEEDED(op, i))

            needed |= SWS_COMP(op->swizzle.in[i]);

    }

    /* Current mapping of registers to components */

    int idx[4 + 1] = { 0, 1, 2, 3, -1 }; /* +1 for tmp */

    /* Decompose the swizzle mask into a series of register-register moves */

    while (todo) {

        int dst = -1, src = -1;

        /* Find next unsatisfied dst <- src move that doesn't clobber a value */

        for (dst = 0; dst < 4; dst++) {

            if (!SWS_COMP_TEST(todo, dst))

                continue; /* already satisfied */

            const int cur = idx[dst];

            if (count_idx(idx, FF_ARRAY_ELEMS(idx), cur) == 1 && SWS_COMP_TEST(needed, cur))

                continue; /* clobbers last remaining, still-needed value */

            for (src = 0; src < FF_ARRAY_ELEMS(idx); src++) {

                if (idx[src] == op->swizzle.in[dst]) {

                    /* Prevent read-after-write dependency. */

                    if (par->num_moves > 0 && src == par->dst[par->num_moves - 1])

                        src = par->src[par->num_moves - 1];

                    break;

                }

            }

            av_assert1(src < FF_ARRAY_ELEMS(idx));

            todo &= ~SWS_COMP(dst);

            break;

        }

        if (dst == 4) {

            /* Stuck in a cycle, break it by saving to the scratch register */

            dst = 4;

            for (src = 0; src < 4; src++) {

                if (SWS_COMP_TEST(todo, src)) {

                    needed &= ~SWS_COMP(idx[src]);

                    break;

                }

            }

            av_assert1(src < 4);

        }

        av_assert0(par->num_moves < SWS_UOP_MOVE_MAX);

        par->dst[par->num_moves] = dst > 3 ? -1 : dst;

        par->src[par->num_moves] = src > 3 ? -1 : src;

        par->num_moves++;

        idx[dst] = idx[src];

    }

    /* Check for duplicates in the final register map */

    SwsCompMask seen = 0;

    for (int i = 0; i < 4; i++) {

        if (!SWS_COMP_TEST(uop.mask, i))

            continue;

        av_assert2(idx[i] >= 0); /* should be no tmp register */

        const SwsCompMask bit = SWS_COMP(idx[i]);

        if (seen & bit) {

            uop.uop = SWS_UOP_COPY;

            break;

        }

        seen |= bit;

    }

    /* Add any extra unused components to the mask, to prevent generating

     * duplicate uops like permute_xyz_txy_xyt and permute_xyzw_txy_xyt */

    for (int i = 0; i < 4; i++) {

        const SwsCompMask bit = SWS_COMP(i);

        if (!(seen & bit) && idx[i] == i)

            uop.mask |= bit;

    }

    return ff_sws_uop_list_append(ops, &uop);

}

static int translate_dither_op(SwsUOpList *ops, SwsUOpFlags flags, const SwsOp *op)

{

    SwsUOp uop = {

        .type = ff_sws_op_input_type(op),

        .uop  = SWS_UOP_DITHER,

        .par.dither.size_log2 = op->dither.size_log2,

    };

    if ((flags & SWS_UOP_FLAG_ADD) && op->dither.size_log2 == 0) {

        /* Constant offset */

        const SwsPixel val = ff_sws_pixel_from_q64(uop.type, op->dither.matrix[0]);

        uop.uop = SWS_UOP_ADD;

        for (int i = 0; i < 4; i++) {

            if (!SWS_OP_NEEDED(op, i) || op->dither.y_offset[i] < 0)

                continue;

            uop.mask |= SWS_COMP(i);

            uop.data.vec4[i] = val;

        }

        return ff_sws_uop_list_append(ops, &uop);

    }

    const int size = 1 << op->dither.size_log2;

    for (int i = 0; i < 4; i++) {

        if (!SWS_OP_NEEDED(op, i) || op->dither.y_offset[i] < 0)

            continue;

        const uint8_t off = op->dither.y_offset[i] & (size - 1);

        uop.mask |= SWS_COMP(i);

        uop.par.dither.y_offset[i] = off;

    }

    /* Allocate extra rows to allow over-reading for row offsets. Note that

     * y_offset is currently never larger than 5, so the extra space needed

     * for this over-allocation is bounded by 5 * size * sizeof(float),

     * typically 320 bytes for a 16x16 dither matrix. */

    const int stride   = size * sizeof(SwsPixel);

    const int num_rows = ff_sws_dither_height(&uop.par.dither);

    SwsPixel *matrix = uop.data.ptr = av_refstruct_allocz(num_rows * stride);

    if (!matrix)

        return AVERROR(ENOMEM);

    for (int i = 0; i < size * size; i++)

        matrix[i] = ff_sws_pixel_from_q64(uop.type, op->dither.matrix[i]);

    memcpy(&matrix[size * size], matrix, (num_rows - size) * stride);

    return ff_sws_uop_list_append(ops, &uop);

}

static int translate_linear_op(SwsContext *ctx, SwsUOpList *ops,

                               SwsUOpFlags flags, const SwsOp *op,

                               const SwsOpPad inputs[4])

{

    SwsUOp uop = {

        .type = ff_sws_op_input_type(op),

        .uop  = SWS_UOP_LINEAR,

    };

    const SwsPixel one = ff_sws_pixel_from_q64(uop.type, (AVRational64) {1, 1});

    const uint32_t mask = ff_sws_linear_mask(&op->lin);

    const bool bitexact = ctx->flags & SWS_BITEXACT;

    uint32_t exact = 0;

    for (int i = 0; i < 4; i++) {

        if (!SWS_OP_NEEDED(op, i) || !(mask & SWS_MASK_ROW(i))) {

            uop.par.lin.zero |= SWS_MASK_ROW(i) ^ SWS_MASK(i, i);

            uop.par.lin.one |= SWS_MASK(i, i);

            uop.data.mat4x5[i][i] = one;

            continue;

        }

        uop.mask |= SWS_COMP(i);

        bool nonzero = (op->lin.m[i][4].num != 0);

        for (int j = 0; j < 5; j++) {

            const AVRational64 k = op->lin.m[i][j];

            const SwsPixel px = ff_sws_pixel_from_q64(uop.type, k);

            uop.data.mat4x5[i][j] = px;

            if (k.num == 0)

                uop.par.lin.zero |= SWS_MASK(i, j);

            else if (j < 4 && k.num == k.den)

                uop.par.lin.one |= SWS_MASK(i, j);

            else if (j < 4 && nonzero && (!bitexact || exact_prod(px, &inputs[j])))

                exact |= SWS_MASK(i, j);

            if (k.num != 0)

                nonzero = true;

        }

    }

    if ((flags & SWS_UOP_FLAG_FMA) && !ff_sws_pixel_type_is_int(uop.type)) {

        /* multiplication by 1 and 0 are always exact by definition */

        uop.uop = SWS_UOP_LINEAR_FMA;

        uop.par.lin.exact = exact | uop.par.lin.zero | uop.par.lin.one;

    }

    return ff_sws_uop_list_append(ops, &uop);

}

static int translate_op(SwsContext *ctx, SwsUOpList *uops, SwsUOpFlags flags,

                        const SwsOp *op, const SwsOpPad inputs[4])

{

    switch (op->op) {

    case SWS_OP_FILTER_H:

    case SWS_OP_FILTER_V:

        return AVERROR(ENOTSUP); /* always handled by subpass splitting */

    case SWS_OP_READ:

    case SWS_OP_WRITE:

        return translate_rw_op(ctx, uops, flags, op);

    case SWS_OP_SWIZZLE:

        return translate_swizzle(uops, flags, op);

    case SWS_OP_DITHER:

        return translate_dither_op(uops, flags, op);

    case SWS_OP_LINEAR:

        return translate_linear_op(ctx, uops, flags, op, inputs);

    default:

        break;

    }

    /* Default handling for "simple" ops */

    SwsUOp uop = {

        .uop  = SWS_UOP_INVALID,

        .type = ff_sws_op_input_type(op),

        .mask = ff_sws_comp_mask_needed(op),

    };

    switch (op->op) {

    case SWS_OP_CONVERT:

        switch (op->convert.to) {

        case SWS_PIXEL_U8:  uop.uop = SWS_UOP_TO_U8;  break;

        case SWS_PIXEL_U16: uop.uop = SWS_UOP_TO_U16; break;

        case SWS_PIXEL_U32: uop.uop = SWS_UOP_TO_U32; break;

        case SWS_PIXEL_F32: uop.uop = SWS_UOP_TO_F32; break;

        }

        break;

    case SWS_OP_UNPACK:

    case SWS_OP_PACK:

        uop.uop = op->op == SWS_OP_PACK ? SWS_UOP_PACK : SWS_UOP_UNPACK;

        uop.mask = 0;

        for (int i = 0; i < 4 && op->pack.pattern[i]; i++) {

            uop.par.pack.pattern[i] = op->pack.pattern[i];

            if (op->op == SWS_OP_PACK || SWS_OP_NEEDED(op, i))

                uop.mask |= SWS_COMP(i);

        }

        break;

    case SWS_OP_LSHIFT:

    case SWS_OP_RSHIFT:

        uop.uop = op->op == SWS_OP_LSHIFT ? SWS_UOP_LSHIFT : SWS_UOP_RSHIFT;

        uop.par.shift.amount = op->shift.amount;

        break;

    case SWS_OP_CLEAR:

        uop.uop = SWS_UOP_CLEAR;

        uop.mask &= op->clear.mask;

        for (int i = 0; i < 4; i++) {

            if (!SWS_COMP_TEST(op->clear.mask, i))

                continue;

            const AVRational64 v = op->clear.value[i];

            const SwsPixelType type = op->clear.type[i];

            const SwsPixel px = ff_sws_pixel_from_q64(type, v);

            uop.type = pixel_type_to_int(flags, type);

            uop.data.vec4[i] = px;

            if (v.num == 0)

                uop.par.clear.zero |= SWS_COMP(i);

            else if (ff_sws_pixel_is_1s(type, px))

                uop.par.clear.one |= SWS_COMP(i);

        }

        break;

    case SWS_OP_SCALE:

        uop.uop = SWS_UOP_SCALE;

        uop.data.scalar = ff_sws_pixel_from_q64(uop.type, op->scale.factor);

        break;

    case SWS_OP_MIN:

    case SWS_OP_MAX:

        uop.uop = op->op == SWS_OP_MIN ? SWS_UOP_MIN : SWS_UOP_MAX;

        uop.mask &= ff_sws_comp_mask_q4(op->clamp.limit);

        for (int i = 0; i < 4; i++) {

            if (SWS_COMP_TEST(uop.mask, i))

                uop.data.vec4[i] = ff_sws_pixel_from_q64(uop.type, op->clamp.limit[i]);

        }

        break;

    case SWS_OP_SWAP_BYTES:

        uop.uop = SWS_UOP_SWAP_BYTES;

        uop.type = pixel_type_to_int(flags, uop.type);

        break;

    case SWS_OP_LUT_3D:

        uop.uop = SWS_UOP_LUT_3D;

        uop.par.lut3d.dynamic = op->lut3d.dynamic;

        uop.data.lut3d = av_refstruct_ref_c(op->lut3d.lut);

        break;

    default:

        return AVERROR(ENOTSUP);

    }

    av_assert0(uop.uop != SWS_UOP_INVALID);

    return ff_sws_uop_list_append(uops, &uop);

}

int ff_sws_ops_translate(SwsContext *ctx, const SwsOpList *ops,

                         SwsUOpFlags flags, SwsUOpList *uops)

{

    const SwsOpPad *inputs = ops->inputs;

    for (int n = 0; n < ops->num_ops; n++) {

        const SwsOp *op = &ops->ops[n];

        for (int i = 0; i < 4; i++) {

            if (!SWS_OP_NEEDED(op, i))

                continue;

            const int pixel_size = ff_sws_pixel_type_size(op->outputs[i].type);

            if (pixel_size > uops->pixel_size_max)

                uops->pixel_size_max = pixel_size;

        }

        int ret = translate_op(ctx, uops, flags, op, inputs);

        if (ret < 0)

            return ret;

        inputs = op->outputs;

    }

    return ff_sws_uop_list_optimize(ctx, flags, uops);

}