/*

  * copyright (c) Sebastien Bechet <s.bechet@av7.net>

  *

  * 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 <errno.h>

 #include <stdio.h>
 #include <stdlib.h>

 #include <string.h>

 
 #define SCALEBITS 8
 #define ONE_HALF  (1 << (SCALEBITS - 1))
 #define FIX(x)    ((int) ((x) * (1L << SCALEBITS) + 0.5))
 

 #define err_if(expr) do {                                              \
     if (expr) {                                                        \
         fprintf(stderr, "%s\n", strerror(errno));                      \
         exit(1);                                                       \
     }                                                                  \
 } while (0)
 

 static void rgb24_to_yuv420p(unsigned char *lum, unsigned char *cb,
                              unsigned char *cr, unsigned char *src,
                              int width, int height)
 {
     int wrap, wrap3, x, y;
     int r, g, b, r1, g1, b1;
     unsigned char *p;
 
     wrap  = width;
     wrap3 = width * 3;
     p     = src;
     for (y = 0; y < height; y += 2) {
         for (x = 0; x < width; x += 2) {
             r       = p[0];
             g       = p[1];
             b       = p[2];
             r1      = r;
             g1      = g;
             b1      = b;
             lum[0]  = (FIX(0.29900) * r + FIX(0.58700) * g +
                        FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
             r       = p[3];
             g       = p[4];
             b       = p[5];
             r1     += r;
             g1     += g;
             b1     += b;
             lum[1]  = (FIX(0.29900) * r + FIX(0.58700) * g +
                        FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
             p      += wrap3;
             lum    += wrap;
 
             r       = p[0];
             g       = p[1];
             b       = p[2];
             r1     += r;
             g1     += g;
             b1     += b;
             lum[0]  = (FIX(0.29900) * r + FIX(0.58700) * g +
                        FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
             r       = p[3];
             g       = p[4];
             b       = p[5];
             r1     += r;
             g1     += g;
             b1     += b;
             lum[1]  = (FIX(0.29900) * r + FIX(0.58700) * g +
                        FIX(0.11400) * b + ONE_HALF) >> SCALEBITS;
 
             cb[0]   = ((- FIX(0.16874) * r1 - FIX(0.33126) * g1 +
                        FIX(0.50000) * b1 + 4 * ONE_HALF - 1) >> (SCALEBITS + 2)) + 128;
             cr[0]   = ((FIX(0.50000) * r1 - FIX(0.41869) * g1 -
                        FIX(0.08131) * b1 + 4 * ONE_HALF - 1) >> (SCALEBITS + 2)) + 128;
 
             cb++;
             cr++;
             p   += -wrap3 + 2 * 3;
             lum += -wrap  + 2;
         }
         p   += wrap3;
         lum += wrap;
     }
 }
 
 /* cif format */
 #define DEFAULT_WIDTH   352
 #define DEFAULT_HEIGHT  288
 #define DEFAULT_NB_PICT  50
 
 static void pgmyuv_save(const char *filename, int w, int h,
                         unsigned char *rgb_tab)
 {
     FILE *f;
     int i, h2, w2;
     unsigned char *cb, *cr;
     unsigned char *lum_tab, *cb_tab, *cr_tab;
 
     lum_tab = malloc(w * h);
     cb_tab  = malloc(w * h / 4);
     cr_tab  = malloc(w * h / 4);
 
     rgb24_to_yuv420p(lum_tab, cb_tab, cr_tab, rgb_tab, w, h);
 

     if (filename) {
         f = fopen(filename, "wb");
         fprintf(f, "P5\n%d %d\n%d\n", w, h * 3 / 2, 255);
     } else {
         f = stdout;
     }
 

     err_if(fwrite(lum_tab, 1, w * h, f) != w * h);

     h2 = h / 2;
     w2 = w / 2;
     cb = cb_tab;
     cr = cr_tab;

 
     if (filename) {
         for (i = 0; i < h2; i++) {
             err_if(fwrite(cb, 1, w2, f) != w2);
             err_if(fwrite(cr, 1, w2, f) != w2);
             cb += w2;
             cr += w2;
         }
         fclose(f);
     } else {
         for (i = 0; i < h2; i++) {
             err_if(fwrite(cb, 1, w2, f) != w2);
             cb += w2;
         }
         for (i = 0; i < h2; i++) {
             err_if(fwrite(cr, 1, w2, f) != w2);
             cr += w2;
         }

     }
 
     free(lum_tab);
     free(cb_tab);
     free(cr_tab);
 }
 
 static unsigned char *rgb_tab;
 static int width, height, wrap;
 
 static void put_pixel(int x, int y, int r, int g, int b)
 {
     unsigned char *p;
 
     if (x < 0 || x >= width ||
         y < 0 || y >= height)
         return;
 
     p    = rgb_tab + y * wrap + x * 3;
     p[0] = r;
     p[1] = g;
     p[2] = b;
 }