/*
  * 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 <stdlib.h>
 
 #include "libavutil/common.h"
 #include "libavutil/opt.h"
 
 #include "bsf.h"
 #include "cbs.h"
 
 
 typedef struct FilterUnitsContext {
     const AVClass *class;
 
     CodedBitstreamContext *cbc;
     CodedBitstreamFragment fragment;
 
     const char *pass_types;
     const char *remove_types;
 
     enum {
         NOOP,
         PASS,
         REMOVE,
     } mode;
     CodedBitstreamUnitType *type_list;
     int nb_types;
 } FilterUnitsContext;
 
 
 static int filter_units_make_type_list(const char *list_string,
                                        CodedBitstreamUnitType **type_list,
                                        int *nb_types)
 {
     CodedBitstreamUnitType *list = NULL;
     int pass, count;
 
     for (pass = 1; pass <= 2; pass++) {
         long value, range_start, range_end;
         const char *str;
         char *value_end;
 
         count = 0;
         for (str = list_string; *str;) {
             value = strtol(str, &value_end, 0);
             if (str == value_end)
                 goto invalid;
             str = (const char *)value_end;
             if (*str == '-') {
                 ++str;
                 range_start = value;
                 range_end   = strtol(str, &value_end, 0);
                 if (str == value_end)
                     goto invalid;
 
                 for (value = range_start; value < range_end; value++) {
                     if (pass == 2)
                         list[count] = value;
                     ++count;
                 }
             } else {
                 if (pass == 2)
                     list[count] = value;
                 ++count;
             }
             if (*str == '|')
                 ++str;
         }
         if (pass == 1) {
             list = av_malloc_array(count, sizeof(*list));
             if (!list)
                 return AVERROR(ENOMEM);
         }
     }
 
     *type_list = list;
     *nb_types  = count;
     return 0;
 
 invalid:
     av_freep(&list);
     return AVERROR(EINVAL);
 }
 
 static int filter_units_filter(AVBSFContext *bsf, AVPacket *out)
 {
     FilterUnitsContext      *ctx = bsf->priv_data;
     CodedBitstreamFragment *frag = &ctx->fragment;
     AVPacket *in = NULL;
     int err, i, j;
 
     while (1) {
         err = ff_bsf_get_packet(bsf, &in);
         if (err < 0)
             return err;
 
         if (ctx->mode == NOOP) {
             av_packet_move_ref(out, in);
             av_packet_free(&in);
             return 0;
         }
 
         err = ff_cbs_read_packet(ctx->cbc, frag, in);
         if (err < 0) {
             av_log(bsf, AV_LOG_ERROR, "Failed to read packet.\n");
             goto fail;
         }
 
         for (i = 0; i < frag->nb_units; i++) {
             for (j = 0; j < ctx->nb_types; j++) {
                 if (frag->units[i].type == ctx->type_list[j])
                     break;
             }
             if (ctx->mode == REMOVE ? j <  ctx->nb_types
                                     : j >= ctx->nb_types) {
                 ff_cbs_delete_unit(ctx->cbc, frag, i);
                 --i;
             }
         }
 
         if (frag->nb_units > 0)
             break;
 
         // Don't return packets with nothing in them.
         av_packet_free(&in);
         ff_cbs_fragment_uninit(ctx->cbc, frag);
     }
 
     err = ff_cbs_write_packet(ctx->cbc, out, frag);
     if (err < 0) {
         av_log(bsf, AV_LOG_ERROR, "Failed to write packet.\n");
         goto fail;
     }
 
     err = av_packet_copy_props(out, in);
     if (err < 0)
         goto fail;
 
 fail:
     ff_cbs_fragment_uninit(ctx->cbc, frag);
     av_packet_free(&in);
 
     return err;
 }
 
 static int filter_units_init(AVBSFContext *bsf)
 {
     FilterUnitsContext *ctx = bsf->priv_data;
     int err;
 
     if (ctx->pass_types && ctx->remove_types) {
         av_log(bsf, AV_LOG_ERROR, "Exactly one of pass_types or "
                "remove_types is required.\n");
         return AVERROR(EINVAL);
     }
 
     if (ctx->pass_types) {
         ctx->mode = PASS;
         err = filter_units_make_type_list(ctx->pass_types,
                                           &ctx->type_list, &ctx->nb_types);
         if (err < 0) {
             av_log(bsf, AV_LOG_ERROR, "Failed to parse pass_types.\n");
             return err;
         }
     } else if (ctx->remove_types) {
         ctx->mode = REMOVE;
         err = filter_units_make_type_list(ctx->remove_types,
                                           &ctx->type_list, &ctx->nb_types);
         if (err < 0) {
             av_log(bsf, AV_LOG_ERROR, "Failed to parse remove_types.\n");
             return err;
         }
     } else {
         return 0;
     }
 
     err = ff_cbs_init(&ctx->cbc, bsf->par_in->codec_id, bsf);
     if (err < 0)
         return err;
 
     // Don't actually decompose anything, we only want the unit data.
     ctx->cbc->decompose_unit_types    = ctx->type_list;
     ctx->cbc->nb_decompose_unit_types = 0;
 
     if (bsf->par_in->extradata) {
         CodedBitstreamFragment ps;
 
         err = ff_cbs_read_extradata(ctx->cbc, &ps, bsf->par_in);
         if (err < 0) {
             av_log(bsf, AV_LOG_ERROR, "Failed to read extradata.\n");
         } else {
             err = ff_cbs_write_extradata(ctx->cbc, bsf->par_out, &ps);
             if (err < 0)
                 av_log(bsf, AV_LOG_ERROR, "Failed to write extradata.\n");
         }
 
         ff_cbs_fragment_uninit(ctx->cbc, &ps);
     }
 
     return err;
 }
 
 static void filter_units_close(AVBSFContext *bsf)
 {
     FilterUnitsContext *ctx = bsf->priv_data;
 
     av_freep(&ctx->type_list);
 
     ff_cbs_close(&ctx->cbc);
 }
 
 #define OFFSET(x) offsetof(FilterUnitsContext, x)
 #define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_BSF_PARAM)
 static const AVOption filter_units_options[] = {
     { "pass_types",   "List of unit types to pass through the filter.",
         OFFSET(pass_types),   AV_OPT_TYPE_STRING,
         { .str = NULL }, .flags = FLAGS },
     { "remove_types", "List of unit types to remove in the filter.",
         OFFSET(remove_types), AV_OPT_TYPE_STRING,
         { .str = NULL }, .flags = FLAGS },
 
     { NULL }
 };
 
 static const AVClass filter_units_class = {
     .class_name = "filter_units",
     .item_name  = av_default_item_name,
     .option     = filter_units_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 const AVBitStreamFilter ff_filter_units_bsf = {
     .name           = "filter_units",
     .priv_data_size = sizeof(FilterUnitsContext),
     .priv_class     = &filter_units_class,
     .init           = &filter_units_init,
     .close          = &filter_units_close,
     .filter         = &filter_units_filter,
     .codec_ids      = ff_cbs_all_codec_ids,
 };