/*

 * 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

 */

/**

 * @file

 * Slice multithreading support functions

 * @see doc/multithreading.txt

 */

#include "avcodec.h"

#include "codec_internal.h"

#include "internal.h"

#include "pthread_internal.h"

#include "thread.h"

#include "libavutil/attributes.h"

#include "libavutil/cpu.h"

#include "libavutil/macros.h"

#include "libavutil/mem.h"

#include "libavutil/slicethread.h"

typedef int (action_func)(AVCodecContext *c, void *arg);

typedef int (action_func2)(AVCodecContext *c, void *arg, int jobnr, int threadnr);

typedef int (main_func)(AVCodecContext *c);

typedef struct SliceThreadContext {

    AVSliceThread *thread;

    action_func *func;

    action_func2 *func2;

    main_func *mainfunc;

    void *args;

    int *rets;

    int job_size;

} SliceThreadContext;

static int main_function(void *priv) {

    AVCodecContext *avctx = priv;

    SliceThreadContext *c = avctx->internal->thread_ctx;

    c->mainfunc(avctx);

    return 0;

}

static int worker_func(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads)

{

    AVCodecContext *avctx = priv;

    SliceThreadContext *c = avctx->internal->thread_ctx;

    int ret;

    ret = c->func ? c->func(avctx, (char *)c->args + c->job_size * jobnr)

                  : c->func2(avctx, c->args, jobnr, threadnr);

    if (c->rets)

        c->rets[jobnr] = ret;

    return 0;

}

av_cold void ff_slice_thread_free(AVCodecContext *avctx)

{

    SliceThreadContext *c = avctx->internal->thread_ctx;

    avpriv_slicethread_free(&c->thread);

    av_freep(&avctx->internal->thread_ctx);

}

static int thread_execute(AVCodecContext *avctx, action_func* func, void *arg, int *ret, int job_count, int job_size)

{

    SliceThreadContext *c = avctx->internal->thread_ctx;

    if (!(avctx->active_thread_type&FF_THREAD_SLICE) || avctx->thread_count <= 1)

        return avcodec_default_execute(avctx, func, arg, ret, job_count, job_size);

    if (job_count <= 0)

        return 0;

    c->job_size = job_size;

    c->args = arg;

    c->func = func;

    c->rets = ret;

    avpriv_slicethread_execute2(c->thread, job_count, !!c->mainfunc  );

    return 0;

}

static int thread_execute2(AVCodecContext *avctx, action_func2* func2, void *arg, int *ret, int job_count)

{

    SliceThreadContext *c = avctx->internal->thread_ctx;

    c->func2 = func2;

    return thread_execute(avctx, NULL, arg, ret, job_count, 0);

}

int ff_slice_thread_execute_with_mainfunc(AVCodecContext *avctx, action_func2* func2, main_func *mainfunc, void *arg, int *ret, int job_count)

{

    SliceThreadContext *c = avctx->internal->thread_ctx;

    c->func2 = func2;

    c->mainfunc = mainfunc;

    return thread_execute(avctx, NULL, arg, ret, job_count, 0);

}

av_cold int ff_slice_thread_init(AVCodecContext *avctx)

{

    SliceThreadContext *c;

    int thread_count = avctx->thread_count;

    int (*mainfunc)(void *);

    if (!thread_count) {

        int nb_cpus = av_cpu_count();

        if  (avctx->height)

            nb_cpus = FFMIN(nb_cpus, (avctx->height+15)/16);

        // use number of cores + 1 as thread count if there is more than one

        if (nb_cpus > 1)

            thread_count = avctx->thread_count = FFMIN(nb_cpus + 1, MAX_AUTO_THREADS);

        else

            thread_count = avctx->thread_count = 1;

    }

    if (thread_count <= 1) {

        avctx->active_thread_type = 0;

        return 0;

    }

    avctx->internal->thread_ctx = c = av_mallocz(sizeof(*c));

    if (!c)

        return AVERROR(ENOMEM);

    mainfunc = ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_SLICE_THREAD_HAS_MF ? &main_function : NULL;

    thread_count = avpriv_slicethread_create2(&c->thread, avctx, worker_func,

                                              mainfunc, thread_count);

    if (thread_count <= 1) {

        ff_slice_thread_free(avctx);

        avctx->thread_count = 1;

        avctx->active_thread_type = 0;

        return thread_count < 0 ? thread_count : 0;

    }

    avctx->thread_count = thread_count;

    avctx->execute = thread_execute;

    avctx->execute2 = thread_execute2;

    return 0;

}