/*
  * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
  * Copyright (c) 2011 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 General Public License as published by
  * the Free Software Foundation; either version 2 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 General Public License for more details.
  *
  * You should have received a copy of the GNU 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
  * Apply a boxblur filter to the input video.
  * Ported from MPlayer libmpcodecs/vf_boxblur.c.
  */
 
 #include "libavutil/avstring.h"

 #include "libavutil/common.h"

 #include "libavutil/eval.h"

 #include "libavutil/opt.h"

 #include "libavutil/pixdesc.h"
 #include "avfilter.h"

 #include "formats.h"

 #include "internal.h"

 #include "video.h"

 static const char *const var_names[] = {

     "w",
     "h",
     "cw",
     "ch",
     "hsub",
     "vsub",
     NULL
 };
 
 enum var_name {
     VAR_W,
     VAR_H,
     VAR_CW,
     VAR_CH,
     VAR_HSUB,
     VAR_VSUB,
     VARS_NB
 };
 
 typedef struct {
     int radius;
     int power;

     char *radius_expr;

 } FilterParam;
 
 typedef struct {

     const AVClass *class;

     FilterParam luma_param;
     FilterParam chroma_param;
     FilterParam alpha_param;
 
     int hsub, vsub;
     int radius[4];
     int power[4];
     uint8_t *temp[2]; ///< temporary buffer used in blur_power()
 } BoxBlurContext;
 

 #define OFFSET(x) offsetof(BoxBlurContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption boxblur_options[] = {
     { "luma_radius", "set luma radius", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
     { "lr",          "set luma radius", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
     { "luma_power",  "set luma power",  OFFSET(luma_param.power), AV_OPT_TYPE_INT, {.i64=2}, 0, INT_MAX, .flags = FLAGS },
     { "lp",          "set luma power",  OFFSET(luma_param.power), AV_OPT_TYPE_INT, {.i64=2}, 0, INT_MAX, .flags = FLAGS },
 
     { "chroma_radius", "set chroma radius", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "cr",            "set chroma radius", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "chroma_power",  "set chroma power",  OFFSET(chroma_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
     { "cp",            "set chroma power",  OFFSET(chroma_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
 
     { "alpha_radius", "set alpha radius", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "ar",           "set alpha radius", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
     { "alpha_power",  "set alpha power",  OFFSET(alpha_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
     { "ap",           "set alpha power",  OFFSET(alpha_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
 
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(boxblur);
 

 #define Y 0
 #define U 1
 #define V 2
 #define A 3
 

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

 {
     BoxBlurContext *boxblur = ctx->priv;

     static const char *shorthand[] = {
         "luma_radius",   "luma_power",
         "chroma_radius", "chroma_power",
         "alpha_radius",  "alpha_power",
         NULL
     };
     int ret;

     boxblur->class = &boxblur_class;
     av_opt_set_defaults(boxblur);

     if ((ret = av_opt_set_from_string(boxblur, args, shorthand, "=", ":")) < 0)
         return ret;

     /* fill missing params */
     if (!boxblur->chroma_param.radius_expr) {
         boxblur->chroma_param.radius_expr = av_strdup(boxblur->luma_param.radius_expr);
         if (!boxblur->chroma_param.radius_expr)
             return AVERROR(ENOMEM);

     }

     if (boxblur->chroma_param.power < 0)

         boxblur->chroma_param.power = boxblur->luma_param.power;

 
     if (!boxblur->alpha_param.radius_expr) {
         boxblur->alpha_param.radius_expr = av_strdup(boxblur->luma_param.radius_expr);
         if (!boxblur->alpha_param.radius_expr)
             return AVERROR(ENOMEM);

     }

     if (boxblur->alpha_param.power < 0)

         boxblur->alpha_param.power = boxblur->luma_param.power;
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     BoxBlurContext *boxblur = ctx->priv;
 
     av_freep(&boxblur->temp[0]);
     av_freep(&boxblur->temp[1]);

     av_opt_free(boxblur);

 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = {

         AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,  AV_PIX_FMT_YUVA420P,
         AV_PIX_FMT_YUV440P,  AV_PIX_FMT_GRAY8,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVJ440P,
         AV_PIX_FMT_NONE

     };
 

     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));

     return 0;
 }
 
 static int config_input(AVFilterLink *inlink)
 {

     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);

     AVFilterContext    *ctx = inlink->dst;

     BoxBlurContext *boxblur = ctx->priv;
     int w = inlink->w, h = inlink->h;
     int cw, ch;
     double var_values[VARS_NB], res;
     char *expr;
     int ret;
 

     if (!(boxblur->temp[0] = av_malloc(FFMAX(w, h))) ||
         !(boxblur->temp[1] = av_malloc(FFMAX(w, h))))

         return AVERROR(ENOMEM);
 
     boxblur->hsub = desc->log2_chroma_w;
     boxblur->vsub = desc->log2_chroma_h;
 

     var_values[VAR_W]       = inlink->w;
     var_values[VAR_H]       = inlink->h;

     var_values[VAR_CW] = cw = w>>boxblur->hsub;
     var_values[VAR_CH] = ch = h>>boxblur->vsub;

     var_values[VAR_HSUB]    = 1<<boxblur->hsub;
     var_values[VAR_VSUB]    = 1<<boxblur->vsub;

 
 #define EVAL_RADIUS_EXPR(comp)                                          \

     expr = boxblur->comp##_param.radius_expr;                           \

     ret = av_expr_parse_and_eval(&res, expr, var_names, var_values,     \
                                  NULL, NULL, NULL, NULL, NULL, 0, ctx); \
     boxblur->comp##_param.radius = res;                                 \
     if (ret < 0) {                                                      \
         av_log(NULL, AV_LOG_ERROR,                                      \
                "Error when evaluating " #comp " radius expression '%s'\n", expr); \
         return ret;                                                     \
     }
     EVAL_RADIUS_EXPR(luma);
     EVAL_RADIUS_EXPR(chroma);
     EVAL_RADIUS_EXPR(alpha);
 

     av_log(ctx, AV_LOG_VERBOSE,

            "luma_radius:%d luma_power:%d "
            "chroma_radius:%d chroma_power:%d "
            "alpha_radius:%d alpha_power:%d "
            "w:%d chroma_w:%d h:%d chroma_h:%d\n",
            boxblur->luma_param  .radius, boxblur->luma_param  .power,
            boxblur->chroma_param.radius, boxblur->chroma_param.power,
            boxblur->alpha_param .radius, boxblur->alpha_param .power,
            w, cw, h, ch);
 
 #define CHECK_RADIUS_VAL(w_, h_, comp)                                  \
     if (boxblur->comp##_param.radius < 0 ||                             \
         2*boxblur->comp##_param.radius > FFMIN(w_, h_)) {               \
         av_log(ctx, AV_LOG_ERROR,                                       \
                "Invalid " #comp " radius value %d, must be >= 0 and <= %d\n", \
                boxblur->comp##_param.radius, FFMIN(w_, h_)/2);          \
         return AVERROR(EINVAL);                                         \
     }
     CHECK_RADIUS_VAL(w,  h,  luma);
     CHECK_RADIUS_VAL(cw, ch, chroma);
     CHECK_RADIUS_VAL(w,  h,  alpha);
 
     boxblur->radius[Y] = boxblur->luma_param.radius;
     boxblur->radius[U] = boxblur->radius[V] = boxblur->chroma_param.radius;
     boxblur->radius[A] = boxblur->alpha_param.radius;
 
     boxblur->power[Y] = boxblur->luma_param.power;
     boxblur->power[U] = boxblur->power[V] = boxblur->chroma_param.power;
     boxblur->power[A] = boxblur->alpha_param.power;
 
     return 0;
 }
 
 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,

                         int len, int radius)

 {
     /* Naive boxblur would sum source pixels from x-radius .. x+radius
      * for destination pixel x. That would be O(radius*width).
      * If you now look at what source pixels represent 2 consecutive
      * output pixels, then you see they are almost identical and only
      * differ by 2 pixels, like:
      * src0       111111111
      * dst0           1
      * src1        111111111
      * dst1            1
      * src0-src1  1       -1
      * so when you know one output pixel you can find the next by just adding
      * and subtracting 1 input pixel.
      * The following code adopts this faster variant.
      */
     const int length = radius*2 + 1;
     const int inv = ((1<<16) + length/2)/length;

     int x, sum = 0;

 
     for (x = 0; x < radius; x++)
         sum += src[x*src_step]<<1;
     sum += src[radius*src_step];
 
     for (x = 0; x <= radius; x++) {
         sum += src[(radius+x)*src_step] - src[(radius-x)*src_step];
         dst[x*dst_step] = (sum*inv + (1<<15))>>16;
     }
 

     for (; x < len-radius; x++) {

         sum += src[(radius+x)*src_step] - src[(x-radius-1)*src_step];
         dst[x*dst_step] = (sum*inv + (1<<15))>>16;
     }
 

     for (; x < len; x++) {
         sum += src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step];

         dst[x*dst_step] = (sum*inv + (1<<15))>>16;
     }
 }
 
 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,

                               int len, int radius, int power, uint8_t *temp[2])

 {
     uint8_t *a = temp[0], *b = temp[1];
 
     if (radius && power) {

         blur(a, 1, src, src_step, len, radius);

         for (; power > 2; power--) {
             uint8_t *c;

             blur(b, 1, a, 1, len, radius);

             c = a; a = b; b = c;
         }
         if (power > 1) {

             blur(dst, dst_step, a, 1, len, radius);

         } else {
             int i;

             for (i = 0; i < len; i++)

                 dst[i*dst_step] = a[i];
         }
     } else {
         int i;

         for (i = 0; i < len; i++)

             dst[i*dst_step] = src[i*src_step];
     }
 }
 
 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
                   int w, int h, int radius, int power, uint8_t *temp[2])
 {
     int y;
 
     if (radius == 0 && dst == src)
         return;
 
     for (y = 0; y < h; y++)
         blur_power(dst + y*dst_linesize, 1, src + y*src_linesize, 1,
                    w, radius, power, temp);
 }
 
 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
                   int w, int h, int radius, int power, uint8_t *temp[2])
 {
     int x;
 
     if (radius == 0 && dst == src)
         return;
 
     for (x = 0; x < w; x++)
         blur_power(dst + x, dst_linesize, src + x, src_linesize,
                    h, radius, power, temp);
 }
 

 static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *in)

 {
     AVFilterContext *ctx = inlink->dst;
     BoxBlurContext *boxblur = ctx->priv;
     AVFilterLink *outlink = inlink->dst->outputs[0];

     AVFilterBufferRef *out;

     int plane;

     int cw = inlink->w >> boxblur->hsub, ch = in->video->h >> boxblur->vsub;

     int w[4] = { inlink->w, cw, cw, inlink->w };

     int h[4] = { in->video->h, ch, ch, in->video->h };

     out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
     if (!out) {
         avfilter_unref_bufferp(&in);
         return AVERROR(ENOMEM);
     }
     avfilter_copy_buffer_ref_props(out, in);
 
     for (plane = 0; in->data[plane] && plane < 4; plane++)
         hblur(out->data[plane], out->linesize[plane],
               in ->data[plane], in ->linesize[plane],

               w[plane], h[plane], boxblur->radius[plane], boxblur->power[plane],
               boxblur->temp);
 

     for (plane = 0; in->data[plane] && plane < 4; plane++)
         vblur(out->data[plane], out->linesize[plane],
               out->data[plane], out->linesize[plane],

               w[plane], h[plane], boxblur->radius[plane], boxblur->power[plane],
               boxblur->temp);

     avfilter_unref_bufferp(&in);
 
     return ff_filter_frame(outlink, out);

 }
 

 static const AVFilterPad avfilter_vf_boxblur_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_input,

         .filter_frame = filter_frame,

         .min_perms    = AV_PERM_READ
     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_vf_boxblur_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 

 AVFilter avfilter_vf_boxblur = {
     .name          = "boxblur",
     .description   = NULL_IF_CONFIG_SMALL("Blur the input."),
     .priv_size     = sizeof(BoxBlurContext),
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
 

     .inputs    = avfilter_vf_boxblur_inputs,
     .outputs   = avfilter_vf_boxblur_outputs,

 
     .priv_class = &boxblur_class,

 };