/*
  * Copyright (c) 2012 Google, Inc.
  *

  * 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
  * audio channel mapping filter
  */
 
 #include <ctype.h>
 
 #include "libavutil/avstring.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/common.h"

 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "libavutil/samplefmt.h"
 
 #include "audio.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 
 struct ChannelMap {
     uint64_t in_channel;
     uint64_t out_channel;
     int in_channel_idx;
     int out_channel_idx;
 };
 
 enum MappingMode {
     MAP_NONE,
     MAP_ONE_INT,
     MAP_ONE_STR,
     MAP_PAIR_INT_INT,
     MAP_PAIR_INT_STR,
     MAP_PAIR_STR_INT,
     MAP_PAIR_STR_STR
 };
 
 #define MAX_CH 64
 typedef struct ChannelMapContext {
     const AVClass *class;
     AVFilterChannelLayouts *channel_layouts;
     char *mapping_str;
     char *channel_layout_str;
     uint64_t output_layout;
     struct ChannelMap map[MAX_CH];
     int nch;
     enum MappingMode mode;
 } ChannelMapContext;
 
 #define OFFSET(x) offsetof(ChannelMapContext, x)
 #define A AV_OPT_FLAG_AUDIO_PARAM

 #define F AV_OPT_FLAG_FILTERING_PARAM

 static const AVOption options[] = {
     { "map", "A comma-separated list of input channel numbers in output order.",

           OFFSET(mapping_str),        AV_OPT_TYPE_STRING, .flags = A|F },

     { "channel_layout", "Output channel layout.",

           OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, .flags = A|F },

     { NULL },
 };
 
 static const AVClass channelmap_class = {
     .class_name = "channel map filter",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 static char* split(char *message, char delim) {
     char *next = strchr(message, delim);
     if (next)
       *next++ = '\0';
     return next;
 }
 
 static int get_channel_idx(char **map, int *ch, char delim, int max_ch)
 {
     char *next = split(*map, delim);
     int len;
     int n = 0;
     if (!next && delim == '-')
         return AVERROR(EINVAL);
     len = strlen(*map);
     sscanf(*map, "%d%n", ch, &n);
     if (n != len)
         return AVERROR(EINVAL);
     if (*ch < 0 || *ch > max_ch)
         return AVERROR(EINVAL);
     *map = next;
     return 0;
 }
 
 static int get_channel(char **map, uint64_t *ch, char delim)
 {
     char *next = split(*map, delim);
     if (!next && delim == '-')
         return AVERROR(EINVAL);
     *ch = av_get_channel_layout(*map);
     if (av_get_channel_layout_nb_channels(*ch) != 1)
         return AVERROR(EINVAL);
     *map = next;
     return 0;
 }
 

 static av_cold int channelmap_init(AVFilterContext *ctx, const char *args)

 {
     ChannelMapContext *s = ctx->priv;
     int ret;
     char *mapping;
     int map_entries = 0;
     char buf[256];
     enum MappingMode mode;
     uint64_t out_ch_mask = 0;
     int i;
 
     if (!args) {
         av_log(ctx, AV_LOG_ERROR, "No parameters supplied.\n");
         return AVERROR(EINVAL);
     }
 
     s->class = &channelmap_class;
     av_opt_set_defaults(s);
 

     if ((ret = av_set_options_string(s, args, "=", ":")) < 0)

         return ret;
 
     mapping = s->mapping_str;
 
     if (!mapping) {
         mode = MAP_NONE;
     } else {
         char *dash = strchr(mapping, '-');
         if (!dash) {  // short mapping
             if (isdigit(*mapping))
                 mode = MAP_ONE_INT;
             else
                 mode = MAP_ONE_STR;
         } else if (isdigit(*mapping)) {
             if (isdigit(*(dash+1)))
                 mode = MAP_PAIR_INT_INT;
             else
                 mode = MAP_PAIR_INT_STR;
         } else {
             if (isdigit(*(dash+1)))
                 mode = MAP_PAIR_STR_INT;
             else
                 mode = MAP_PAIR_STR_STR;
         }
     }
 
     if (mode != MAP_NONE) {
         char *comma = mapping;
         map_entries = 1;
         while ((comma = strchr(comma, ','))) {
             if (*++comma)  // Allow trailing comma
                 map_entries++;
         }
     }
 
     if (map_entries > MAX_CH) {
         av_log(ctx, AV_LOG_ERROR, "Too many channels mapped: '%d'.\n", map_entries);
         ret = AVERROR(EINVAL);
         goto fail;
     }
 
     for (i = 0; i < map_entries; i++) {
         int in_ch_idx = -1, out_ch_idx = -1;
         uint64_t in_ch = 0, out_ch = 0;
         static const char err[] = "Failed to parse channel map\n";
         switch (mode) {
         case MAP_ONE_INT:
             if (get_channel_idx(&mapping, &in_ch_idx, ',', MAX_CH) < 0) {
                 ret = AVERROR(EINVAL);
                 av_log(ctx, AV_LOG_ERROR, err);
                 goto fail;
             }
             s->map[i].in_channel_idx  = in_ch_idx;
             s->map[i].out_channel_idx = i;
             break;
         case MAP_ONE_STR:
             if (!get_channel(&mapping, &in_ch, ',')) {
                 av_log(ctx, AV_LOG_ERROR, err);
                 ret = AVERROR(EINVAL);
                 goto fail;
             }
             s->map[i].in_channel      = in_ch;
             s->map[i].out_channel_idx = i;
             break;
         case MAP_PAIR_INT_INT:
             if (get_channel_idx(&mapping, &in_ch_idx, '-', MAX_CH) < 0 ||
                 get_channel_idx(&mapping, &out_ch_idx, ',', MAX_CH) < 0) {
                 av_log(ctx, AV_LOG_ERROR, err);
                 ret = AVERROR(EINVAL);
                 goto fail;
             }
             s->map[i].in_channel_idx  = in_ch_idx;
             s->map[i].out_channel_idx = out_ch_idx;
             break;
         case MAP_PAIR_INT_STR:
             if (get_channel_idx(&mapping, &in_ch_idx, '-', MAX_CH) < 0 ||
                 get_channel(&mapping, &out_ch, ',') < 0 ||
                 out_ch & out_ch_mask) {
                 av_log(ctx, AV_LOG_ERROR, err);
                 ret = AVERROR(EINVAL);
                 goto fail;
             }
             s->map[i].in_channel_idx  = in_ch_idx;
             s->map[i].out_channel     = out_ch;
             out_ch_mask |= out_ch;
             break;
         case MAP_PAIR_STR_INT:
             if (get_channel(&mapping, &in_ch, '-') < 0 ||
                 get_channel_idx(&mapping, &out_ch_idx, ',', MAX_CH) < 0) {
                 av_log(ctx, AV_LOG_ERROR, err);
                 ret = AVERROR(EINVAL);
                 goto fail;
             }
             s->map[i].in_channel      = in_ch;
             s->map[i].out_channel_idx = out_ch_idx;
             break;
         case MAP_PAIR_STR_STR:
             if (get_channel(&mapping, &in_ch, '-') < 0 ||
                 get_channel(&mapping, &out_ch, ',') < 0 ||
                 out_ch & out_ch_mask) {
                 av_log(ctx, AV_LOG_ERROR, err);
                 ret = AVERROR(EINVAL);
                 goto fail;
             }
             s->map[i].in_channel = in_ch;
             s->map[i].out_channel = out_ch;
             out_ch_mask |= out_ch;
             break;
         }
     }
     s->mode          = mode;
     s->nch           = map_entries;
     s->output_layout = out_ch_mask ? out_ch_mask :
                        av_get_default_channel_layout(map_entries);
 
     if (s->channel_layout_str) {
         uint64_t fmt;
         if ((fmt = av_get_channel_layout(s->channel_layout_str)) == 0) {
             av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout: '%s'.\n",
                    s->channel_layout_str);
             ret = AVERROR(EINVAL);
             goto fail;
         }
         if (mode == MAP_NONE) {
             int i;
             s->nch = av_get_channel_layout_nb_channels(fmt);
             for (i = 0; i < s->nch; i++) {
                 s->map[i].in_channel_idx  = i;
                 s->map[i].out_channel_idx = i;
             }
         } else if (out_ch_mask && out_ch_mask != fmt) {
             av_get_channel_layout_string(buf, sizeof(buf), 0, out_ch_mask);
             av_log(ctx, AV_LOG_ERROR,
                    "Output channel layout '%s' does not match the list of channel mapped: '%s'.\n",
                    s->channel_layout_str, buf);
             ret = AVERROR(EINVAL);
             goto fail;
         } else if (s->nch != av_get_channel_layout_nb_channels(fmt)) {
             av_log(ctx, AV_LOG_ERROR,
                    "Output channel layout %s does not match the number of channels mapped %d.\n",
                    s->channel_layout_str, s->nch);
             ret = AVERROR(EINVAL);
             goto fail;
         }
         s->output_layout = fmt;
     }
     ff_add_channel_layout(&s->channel_layouts, s->output_layout);
 
     if (mode == MAP_PAIR_INT_STR || mode == MAP_PAIR_STR_STR) {
         for (i = 0; i < s->nch; i++) {
             s->map[i].out_channel_idx = av_get_channel_layout_channel_index(
                 s->output_layout, s->map[i].out_channel);
         }
     }
 
 fail:
     av_opt_free(s);
     return ret;
 }
 
 static int channelmap_query_formats(AVFilterContext *ctx)
 {
     ChannelMapContext *s = ctx->priv;
 
     ff_set_common_formats(ctx, ff_planar_sample_fmts());
     ff_set_common_samplerates(ctx, ff_all_samplerates());
     ff_channel_layouts_ref(ff_all_channel_layouts(), &ctx->inputs[0]->out_channel_layouts);
     ff_channel_layouts_ref(s->channel_layouts,       &ctx->outputs[0]->in_channel_layouts);
 
     return 0;
 }
 

 static int channelmap_filter_frame(AVFilterLink *inlink, AVFilterBufferRef *buf)

 {
     AVFilterContext  *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     const ChannelMapContext *s = ctx->priv;
     const int nch_in = av_get_channel_layout_nb_channels(inlink->channel_layout);
     const int nch_out = s->nch;
     int ch;
     uint8_t *source_planes[MAX_CH];
 
     memcpy(source_planes, buf->extended_data,
            nch_in * sizeof(source_planes[0]));
 
     if (nch_out > nch_in) {
         if (nch_out > FF_ARRAY_ELEMS(buf->data)) {
             uint8_t **new_extended_data =
                 av_mallocz(nch_out * sizeof(*buf->extended_data));

             if (!new_extended_data) {
                 avfilter_unref_buffer(buf);
                 return AVERROR(ENOMEM);
             }

             if (buf->extended_data == buf->data) {
                 buf->extended_data = new_extended_data;
             } else {
                 av_free(buf->extended_data);

                 buf->extended_data = new_extended_data;

             }
         } else if (buf->extended_data != buf->data) {
             av_free(buf->extended_data);
             buf->extended_data = buf->data;
         }
     }
 
     for (ch = 0; ch < nch_out; ch++) {
         buf->extended_data[s->map[ch].out_channel_idx] =
             source_planes[s->map[ch].in_channel_idx];
     }
 
     if (buf->data != buf->extended_data)
         memcpy(buf->data, buf->extended_data,
            FFMIN(FF_ARRAY_ELEMS(buf->data), nch_out) * sizeof(buf->data[0]));
 

     return ff_filter_frame(outlink, buf);

 }
 
 static int channelmap_config_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     ChannelMapContext *s = ctx->priv;
     int i, err = 0;
     const char *channel_name;
     char layout_name[256];
 
     if (s->mode == MAP_PAIR_STR_INT || s->mode == MAP_PAIR_STR_STR) {
         for (i = 0; i < s->nch; i++) {
             s->map[i].in_channel_idx = av_get_channel_layout_channel_index(
                 inlink->channel_layout, s->map[i].in_channel);
             if (s->map[i].in_channel_idx < 0) {
                 channel_name = av_get_channel_name(s->map[i].in_channel);
                 av_get_channel_layout_string(layout_name, sizeof(layout_name),
                                              0, inlink->channel_layout);
                 av_log(ctx, AV_LOG_ERROR,
                        "input channel '%s' not available from input layout '%s'\n",
                        channel_name, layout_name);
                 err = AVERROR(EINVAL);
             }
         }
     }
 
     return err;
 }
 

 static const AVFilterPad avfilter_af_channelmap_inputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_AUDIO,

         .min_perms      = AV_PERM_READ | AV_PERM_WRITE,

         .filter_frame   = channelmap_filter_frame,

         .config_props   = channelmap_config_input
     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_af_channelmap_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_AUDIO
     },
     { NULL }
 };
 

 AVFilter avfilter_af_channelmap = {
     .name          = "channelmap",
     .description   = NULL_IF_CONFIG_SMALL("Remap audio channels."),
     .init          = channelmap_init,
     .query_formats = channelmap_query_formats,
     .priv_size     = sizeof(ChannelMapContext),
 

     .inputs        = avfilter_af_channelmap_inputs,
     .outputs       = avfilter_af_channelmap_outputs,

     .priv_class    = &channelmap_class,

 };