/*
  * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder
  *

  * 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
  * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder DSP routines
  */
 
 #include "mss2dsp.h"
 #include "libavutil/common.h"
 
 static av_always_inline void mss2_blit_wmv9_template(uint8_t *dst,
                                                      int dst_stride,
                                                      int gray,
                                                      int use_mask,
                                                      int maskcolor,
                                                      const uint8_t *mask,
                                                      int mask_stride,
                                                      const uint8_t *srcy,
                                                      int srcy_stride,
                                                      const uint8_t *srcu,
                                                      const uint8_t *srcv,
                                                      int srcuv_stride,
                                                      int w, int h)
 {
     int i, j, k, r = -1;
     while (++r < h) {
         for (i = 0, j = 0, k = 0; i < w; j += (i & 1), i++, k += 3) {
             if (!use_mask || mask[i] == maskcolor) {
                 if (gray) {
                     dst[k] = dst[k + 1] = dst[k + 2] = 0x80;
                 } else {
                     int y = srcy[i];
                     int u = srcu[j] - 128;
                     int v = srcv[j] - 128;
                     dst[k]     = av_clip_uint8(y + (             91881 * v + 32768 >> 16));
                     dst[k + 1] = av_clip_uint8(y + (-22554 * u - 46802 * v + 32768 >> 16));
                     dst[k + 2] = av_clip_uint8(y + (116130 * u             + 32768 >> 16));
                 }
             }
         }
         mask +=  mask_stride;
         dst  +=   dst_stride;
         srcy +=  srcy_stride;
         srcu += srcuv_stride * (r & 1);
         srcv += srcuv_stride * (r & 1);
     }
 }
 
 static void mss2_blit_wmv9_c(uint8_t *dst, int dst_stride,
                              const uint8_t *srcy, int srcy_stride,
                              const uint8_t *srcu, const uint8_t *srcv,
                              int srcuv_stride, int w, int h)
 {
     mss2_blit_wmv9_template(dst, dst_stride, 0, 0,
                             0, NULL, 0,
                             srcy, srcy_stride,
                             srcu, srcv, srcuv_stride,
                             w, h);
 }
 
 static void mss2_blit_wmv9_masked_c(uint8_t *dst, int dst_stride,
                                     int maskcolor, const uint8_t *mask,
                                     int mask_stride,
                                     const uint8_t *srcy, int srcy_stride,
                                     const uint8_t *srcu, const uint8_t *srcv,
                                     int srcuv_stride, int w, int h)
 {
     mss2_blit_wmv9_template(dst, dst_stride, 0, 1,
                             maskcolor, mask, mask_stride,
                             srcy, srcy_stride,
                             srcu, srcv, srcuv_stride,
                             w, h);
 }
 
 static void mss2_gray_fill_masked_c(uint8_t *dst, int dst_stride,
                                     int maskcolor, const uint8_t *mask,
                                     int mask_stride, int w, int h)
 {
     mss2_blit_wmv9_template(dst, dst_stride, 1, 1,
                             maskcolor, mask, mask_stride,
                             NULL, 0,
                             NULL, NULL, 0,
                             w, h);
 }
 
 static void upsample_plane_c(uint8_t *plane, int plane_stride, int w, int h)
 {
     uint8_t *src1, *src2, *dst1, *dst2, *p, a, b;
     int i, j;
 

     if(!w || !h)
         return;
 

     w += (w & 1);
     h += (h & 1);
 
     j = h - 1;
 
     memcpy(plane + plane_stride *  j,
            plane + plane_stride * (j >> 1),
            w);
 
     while ((j -= 2) > 0) {
         dst1 = plane + plane_stride *  (j + 1);
         dst2 = plane + plane_stride *   j;
         src1 = plane + plane_stride * ((j + 1) >> 1);
         src2 = plane + plane_stride * ( j      >> 1);
 
         for (i = (w - 1) >> 1; i >= 0; i--) {
             a = src1[i];
             b = src2[i];
             dst1[i] = (3 * a + b + 2) >> 2;
             dst2[i] = (a + 3 * b + 2) >> 2;
         }
     }
 
     for (j = h - 1; j >= 0; j--) {
         p = plane + plane_stride * j;
         i = w - 1;
 
         p[i] = p[i >> 1];
 
         while ((i -= 2) > 0) {
             a = p[ i      >> 1];
             b = p[(i + 1) >> 1];
             p[i]     = (3 * a + b + 1) >> 2;
             p[i + 1] = (a + 3 * b + 1) >> 2;
         }
     }
 }
 
 av_cold void ff_mss2dsp_init(MSS2DSPContext* dsp)
 {
     dsp->mss2_blit_wmv9        = mss2_blit_wmv9_c;
     dsp->mss2_blit_wmv9_masked = mss2_blit_wmv9_masked_c;
     dsp->mss2_gray_fill_masked = mss2_gray_fill_masked_c;
     dsp->upsample_plane        = upsample_plane_c;
 }