[FFmpeg-devel,v3,05/12] avutil/frame: add helper for adding side data to set

Additionally, add an API test to check that the no-duplicates
addition works after duplicates have been inserted.
---
 libavutil/Makefile              |  1 +
 libavutil/frame.c               | 34 ++++++++++++++++
 libavutil/frame.h               | 18 +++++++++
 libavutil/tests/side_data_set.c | 71 +++++++++++++++++++++++++++++++++
 tests/fate/libavutil.mak        |  4 ++
 tests/ref/fate/side_data_set    |  7 ++++
 6 files changed, 135 insertions(+)
 create mode 100644 libavutil/tests/side_data_set.c
 create mode 100644 tests/ref/fate/side_data_set

Jan Ekström:
> Additionally, add an API test to check that the no-duplicates
> addition works after duplicates have been inserted.
> ---
>  libavutil/Makefile              |  1 +
>  libavutil/frame.c               | 34 ++++++++++++++++
>  libavutil/frame.h               | 18 +++++++++
>  libavutil/tests/side_data_set.c | 71 +++++++++++++++++++++++++++++++++
>  tests/fate/libavutil.mak        |  4 ++
>  tests/ref/fate/side_data_set    |  7 ++++
>  6 files changed, 135 insertions(+)
>  create mode 100644 libavutil/tests/side_data_set.c
>  create mode 100644 tests/ref/fate/side_data_set
> 
> diff --git a/libavutil/Makefile b/libavutil/Makefile
> index 7828c94dc5..339eaf3539 100644
> --- a/libavutil/Makefile
> +++ b/libavutil/Makefile
> @@ -264,6 +264,7 @@ TESTPROGS = adler32                                                     \
>              ripemd                                                      \
>              sha                                                         \
>              sha512                                                      \
> +            side_data_set                                               \
>              softfloat                                                   \
>              tree                                                        \
>              twofish                                                     \
> diff --git a/libavutil/frame.c b/libavutil/frame.c
> index 46ea603511..27ccbc52c7 100644
> --- a/libavutil/frame.c
> +++ b/libavutil/frame.c
> @@ -846,6 +846,40 @@ AVFrameSideData *av_frame_new_side_data(AVFrame *frame,
>      return ret;
>  }
>  
> +
> +AVFrameSideData *av_side_data_set_new_item(AVFrameSideDataSet *set,
> +                                           enum AVFrameSideDataType type,
> +                                           size_t size,
> +                                           unsigned int allow_duplicates)
> +{
> +    AVBufferRef     *buf = av_buffer_alloc(size);
> +    AVFrameSideData *ret = NULL;
> +
> +    if (!allow_duplicates) {
> +        for (int i = 0; i < set->nb_sd; i++) {
> +            if (set->sd[i]->type != type)
> +                continue;
> +
> +            free_side_data(&set->sd[i]);
> +
> +            for (int j = i + 1; j < set->nb_sd; j++) {
> +                set->sd[j - 1] = set->sd[j];

Ever heard of memmove?
(Alternatively, if the order is not to be preserved, one could simply
move the last side data to the just freed slot, similarly how
av_frame_remove_side_data() does it.)

> +            }
> +
> +            // finally, cause a retry of the same index and update state
> +            // regarding there being one less side data item in the set.
> +            i--;

In code like this, it is easier to count down instead of up. This also
has the advantage that entries that are removed later are not
unnecessarily moved.

> +            set->nb_sd--;
> +        }
> +    }
> +
> +    ret = add_side_data_to_set_from_buf(set, type, buf);
> +    if (!ret)
> +        av_buffer_unref(&buf);
> +
> +    return ret;
> +}
> +
>  AVFrameSideData *av_frame_get_side_data(const AVFrame *frame,
>                                          enum AVFrameSideDataType type)
>  {
> diff --git a/libavutil/frame.h b/libavutil/frame.h
> index e5ca7af651..b9d7c76461 100644
> --- a/libavutil/frame.h
> +++ b/libavutil/frame.h
> @@ -1065,6 +1065,24 @@ const char *av_frame_side_data_name(enum AVFrameSideDataType type);
>   */
>  void av_side_data_set_uninit(AVFrameSideDataSet *set);
>  
> +/**
> + * Add a new side data entry to a set.
> + *
> + * @param set a set to which the side data should be added
> + * @param type type of the added side data
> + * @param size size of the side data
> + * @param allow_duplicates an unsigned integer noting whether duplicates are
> + *                         allowed or not. If duplicates are not allowed, all
> + *                         entries of the same side data type are first removed
> + *                         and freed before the new entry is added.

Why not flags?

> + *
> + * @return newly added side data on success, NULL on error

This does not mention whether duplicates have been removed on error (if
allow_duplicates == 0).

> + */
> +AVFrameSideData *av_side_data_set_new_item(AVFrameSideDataSet *set,
> +                                           enum AVFrameSideDataType type,
> +                                           size_t size,
> +                                           unsigned int allow_duplicates);
> +
>  /**
>   * @}
>   */
> diff --git a/libavutil/tests/side_data_set.c b/libavutil/tests/side_data_set.c
> new file mode 100644
> index 0000000000..ad420440d5
> --- /dev/null
> +++ b/libavutil/tests/side_data_set.c
> @@ -0,0 +1,71 @@
> +/*
> + * Copyright (c) 2023 Jan Ekström <jeebjp@gmail.com>
> + *
> + * 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 <stdio.h>
> +#include "libavutil/frame.c"
> +#include "libavutil/mastering_display_metadata.h"
> +
> +static void print_clls(const AVFrameSideDataSet set)
> +{
> +    for (int i = 0; i < set.nb_sd; i++) {
> +        AVFrameSideData *sd = set.sd[i];
> +
> +        if (sd->type != AV_FRAME_DATA_CONTENT_LIGHT_LEVEL)
> +            continue;
> +
> +        printf("sd %d, MaxCLL: %u\n",
> +               i, ((AVContentLightMetadata *)sd->data)->MaxCLL);
> +    }
> +}
> +
> +int main(void)
> +{
> +    AVFrameSideDataSet set = { 0 };
> +
> +    for (int value = 1; value < 4; value++) {
> +        AVFrameSideData *sd = av_side_data_set_new_item(
> +            &set, AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,
> +            sizeof(AVContentLightMetadata), 1);
> +
> +        av_assert0(sd);
> +
> +        ((AVContentLightMetadata *)sd->data)->MaxCLL = value;
> +    }
> +
> +    puts("Initial addition results with duplicates:");
> +    print_clls(set);
> +
> +    {
> +        AVFrameSideData *sd = av_side_data_set_new_item(
> +            &set, AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,
> +            sizeof(AVContentLightMetadata), 0);
> +
> +        av_assert0(sd);
> +
> +        ((AVContentLightMetadata *)sd->data)->MaxCLL = 1337;
> +    }
> +
> +    puts("\nFinal state after a single 'no-duplicates' addition:");
> +    print_clls(set);
> +
> +    av_side_data_set_uninit(&set);
> +
> +    return 0;
> +}
> diff --git a/tests/fate/libavutil.mak b/tests/fate/libavutil.mak
> index 80153f4395..6864ea9c03 100644
> --- a/tests/fate/libavutil.mak
> +++ b/tests/fate/libavutil.mak
> @@ -148,6 +148,10 @@ FATE_LIBAVUTIL += fate-sha512
>  fate-sha512: libavutil/tests/sha512$(EXESUF)
>  fate-sha512: CMD = run libavutil/tests/sha512$(EXESUF)
>  
> +FATE_LIBAVUTIL += fate-side_data_set
> +fate-side_data_set: libavutil/tests/side_data_set$(EXESUF)
> +fate-side_data_set: CMD = run libavutil/tests/side_data_set$(EXESUF)
> +
>  FATE_LIBAVUTIL += fate-tree
>  fate-tree: libavutil/tests/tree$(EXESUF)
>  fate-tree: CMD = run libavutil/tests/tree$(EXESUF)
> diff --git a/tests/ref/fate/side_data_set b/tests/ref/fate/side_data_set
> new file mode 100644
> index 0000000000..6fb95d3f7c
> --- /dev/null
> +++ b/tests/ref/fate/side_data_set
> @@ -0,0 +1,7 @@
> +Initial addition results with duplicates:
> +sd 0, MaxCLL: 1
> +sd 1, MaxCLL: 2
> +sd 2, MaxCLL: 3
> +
> +Final state after a single 'no-duplicates' addition:
> +sd 0, MaxCLL: 1337