/*
  * Copyright (c) 2007 Benoit Fouet
  * Copyright (c) 2010 Stefano Sabatini
  *
  * 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

  * horizontal flip filter
  */
 
 #include "avfilter.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/intreadwrite.h"

 #include "libavutil/imgutils.h"

 
 typedef struct {
     int max_step[4];    ///< max pixel step for each plane, expressed as a number of bytes
     int hsub, vsub;     ///< chroma subsampling
 } FlipContext;
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum PixelFormat pix_fmts[] = {
         PIX_FMT_RGB48BE,      PIX_FMT_RGB48LE,

         PIX_FMT_BGR48BE,      PIX_FMT_BGR48LE,

         PIX_FMT_ARGB,         PIX_FMT_RGBA,
         PIX_FMT_ABGR,         PIX_FMT_BGRA,
         PIX_FMT_RGB24,        PIX_FMT_BGR24,
         PIX_FMT_RGB565BE,     PIX_FMT_RGB565LE,
         PIX_FMT_RGB555BE,     PIX_FMT_RGB555LE,
         PIX_FMT_BGR565BE,     PIX_FMT_BGR565LE,
         PIX_FMT_BGR555BE,     PIX_FMT_BGR555LE,
         PIX_FMT_GRAY16BE,     PIX_FMT_GRAY16LE,
         PIX_FMT_YUV420P16LE,  PIX_FMT_YUV420P16BE,
         PIX_FMT_YUV422P16LE,  PIX_FMT_YUV422P16BE,
         PIX_FMT_YUV444P16LE,  PIX_FMT_YUV444P16BE,
         PIX_FMT_YUV444P,      PIX_FMT_YUV422P,
         PIX_FMT_YUV420P,      PIX_FMT_YUV411P,
         PIX_FMT_YUV410P,      PIX_FMT_YUV440P,
         PIX_FMT_YUVJ444P,     PIX_FMT_YUVJ422P,
         PIX_FMT_YUVJ420P,     PIX_FMT_YUVJ440P,
         PIX_FMT_YUVA420P,
         PIX_FMT_RGB8,         PIX_FMT_BGR8,
         PIX_FMT_RGB4_BYTE,    PIX_FMT_BGR4_BYTE,
         PIX_FMT_PAL8,         PIX_FMT_GRAY8,
         PIX_FMT_NONE
     };
 

     avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));

     return 0;
 }
 
 static int config_props(AVFilterLink *inlink)
 {
     FlipContext *flip = inlink->dst->priv;
     const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[inlink->format];
 

     av_image_fill_max_pixsteps(flip->max_step, NULL, pix_desc);

     flip->hsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
     flip->vsub = av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
 
     return 0;
 }
 
 static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
 {
     FlipContext *flip = inlink->dst->priv;
     AVFilterBufferRef *inpic  = inlink->cur_buf;
     AVFilterBufferRef *outpic = inlink->dst->outputs[0]->out_buf;
     uint8_t *inrow, *outrow;
     int i, j, plane, step, hsub, vsub;
 
     for (plane = 0; plane < 4 && inpic->data[plane]; plane++) {
         step = flip->max_step[plane];
         hsub = (plane == 1 || plane == 2) ? flip->hsub : 0;
         vsub = (plane == 1 || plane == 2) ? flip->vsub : 0;
 
         outrow = outpic->data[plane] + (y>>vsub) * outpic->linesize[plane];
         inrow  = inpic ->data[plane] + (y>>vsub) * inpic ->linesize[plane] + ((inlink->w >> hsub) - 1) * step;
         for (i = 0; i < h>>vsub; i++) {
             switch (step) {
             case 1:
             {
                 for (j = 0; j < (inlink->w >> hsub); j++)
                     outrow[j] = inrow[-j];
             }
             break;
 
             case 2:
             {
                 uint16_t *outrow16 = (uint16_t *)outrow;
                 uint16_t * inrow16 = (uint16_t *) inrow;
                 for (j = 0; j < (inlink->w >> hsub); j++)
                     outrow16[j] = inrow16[-j];
             }
             break;
 
             case 3:
             {
                 uint8_t *in  =  inrow;
                 uint8_t *out = outrow;
                 for (j = 0; j < (inlink->w >> hsub); j++, out += 3, in -= 3) {
                     int32_t v = AV_RB24(in);
                     AV_WB24(out, v);
                 }
             }
             break;
 
             case 4:
             {
                 uint32_t *outrow32 = (uint32_t *)outrow;
                 uint32_t * inrow32 = (uint32_t *) inrow;
                 for (j = 0; j < (inlink->w >> hsub); j++)
                     outrow32[j] = inrow32[-j];
             }
             break;
 
             default:
                 for (j = 0; j < (inlink->w >> hsub); j++)
                     memcpy(outrow + j*step, inrow - j*step, step);
             }
 
             inrow  += inpic ->linesize[plane];
             outrow += outpic->linesize[plane];
         }
     }
 
     avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
 }
 
 AVFilter avfilter_vf_hflip = {
     .name      = "hflip",
     .description = NULL_IF_CONFIG_SMALL("Horizontally flip the input video."),
     .priv_size = sizeof(FlipContext),
     .query_formats = query_formats,
 
     .inputs    = (AVFilterPad[]) {{ .name            = "default",
                                     .type            = AVMEDIA_TYPE_VIDEO,
                                     .draw_slice      = draw_slice,
                                     .config_props    = config_props,
                                     .min_perms       = AV_PERM_READ, },
                                   { .name = NULL}},
     .outputs   = (AVFilterPad[]) {{ .name            = "default",
                                     .type            = AVMEDIA_TYPE_VIDEO, },
                                   { .name = NULL}},
 };