Merge branch 'compact_record'

diff --combined lib/png.c
index 5895269,d917cbd..35c1a25
--- 1/lib/png.c
--- 2/lib/png.c
+++ b/lib/png.c
@@@ -358,7 -358,7 +358,7 @@@ static void applyfilter3(int mode, unsi
      }    
  }
  
- static void inline applyfilter4(int mode, unsigned char*src, unsigned char*old, unsigned char*dest, int width)
+ void png_inverse_filter_32(int mode, unsigned char*src, unsigned char*old, unsigned char*dest, int width)
  {
      int x;
      unsigned char lastr=0;
@@@ -441,7 -441,6 +441,6 @@@
      }    
  }
  
- 
  EXPORT int getPNGdimensions(const char*sname, int*destwidth, int*destheight)
  {
      FILE*fi;
@@@ -649,7 -648,7 +648,7 @@@ EXPORT int getPNG(const char*sname, int
                old = &data2[(y-1)*header.width*4];
            }
            if(header.mode == 6) { 
-               applyfilter4(mode, src, old, dest, header.width);
+               png_inverse_filter_32(mode, src, old, dest, header.width);
            } else { // header.mode = 2
                applyfilter3(mode, src, old, dest, header.width);
                /* replace alpha color */
@@@ -1377,7 -1376,7 +1376,7 @@@ static int png_apply_specific_filter_32
      }
      return filtermode;
  }
-     
+ 
  static int*num_bits_table = 0;
  
  static void make_num_bits_table()
@@@ -1396,14 -1395,82 +1395,82 @@@
      }
  }
  
- static int png_apply_filter(unsigned char*dest, unsigned char*src, int width, int y, int bpp)
+ static int png_find_best_filter(unsigned char*src, int width, int bpp, int y)
  {
      make_num_bits_table();
- 
+     
      int num_filters = y>0?5:2; //don't apply y-direction filter in first line
+ 
+     int bytes_per_pixel = bpp>>3;
+     int w = width*bytes_per_pixel;
+     int back_x = bytes_per_pixel;
+     int back_y = y?width*bytes_per_pixel:0;
+ 
+     unsigned char*pairs[5];
+     pairs[0] = calloc(1, 8192);
+     pairs[1] = calloc(1, 8192);
+     pairs[2] = calloc(1, 8192);
+     pairs[3] = calloc(1, 8192);
+     pairs[4] = calloc(1, 8192);
+     
+     unsigned char old[5];
+     int l = bytes_per_pixel - 1;
+     old[0] = src[l];
+     old[1] = src[l];
+     old[2] = src[l] - src[l-back_y];
+     old[3] = src[l] - src[l-back_y];
+     old[4] = src[l] - PaethPredictor(0, src[l-back_y], 0);
+ 
+     int different_pairs[5] = {0,0,0,0,0};
+ 
+     int x;
+     for(x=bytes_per_pixel;x<w;x++) {
+       unsigned char dest[5];
+       dest[0] = src[x];
+       dest[1] = src[x] - src[x-back_x];
+       dest[2] = src[x] - src[x-back_y];
+       dest[3] = src[x] - (src[x-back_x] + src[x-back_y])/2;
+       dest[4] = src[x] - PaethPredictor(src[x-back_x], src[x-back_y], src[x-back_x-back_y]);
+ 
+       int i;
+       for(i=0;i<5;i++) {
+           int v = dest[i]<<8|old[i];
+           int p = v>>3;
+           int b = 1<<(v&7);
+           if(!pairs[i][p]&b) {
+               pairs[i][p]|=b;
+               different_pairs[i]++;
+           }
+       }
+       memcpy(old, dest, sizeof(old));
+     }
      int f;
      int best_nr = 0;
      int best_energy = INT_MAX;
+     for(f=0;f<num_filters;f++) {
+       int energy = different_pairs[f];
+       if(energy<best_energy) {
+           best_nr = f;
+           best_energy = energy;
+       }
+     }
+     free(pairs[0]);
+     free(pairs[1]);
+     free(pairs[2]);
+     free(pairs[3]);
+     free(pairs[4]);
+     return best_nr;
+ }
+     
+     
+ static int png_apply_filter(unsigned char*dest, unsigned char*src, int width, int y, int bpp)
+ {
+     int best_nr = 0;
+ #if 0
+     make_num_bits_table();
+     int num_filters = y>0?5:2; //don't apply y-direction filter in first line
+     int f;
+     int best_energy = INT_MAX;
      int w = width*(bpp/8);
      unsigned char* pairs = malloc(8192);
      assert(bpp==8 || bpp==32);
@@@ -1433,11 -1500,14 +1500,14 @@@
            best_energy = energy;
        }
      }
+     free(pairs);
+ #else
+     best_nr = png_find_best_filter(src, width, bpp, y);
+ #endif
      if(bpp==8)
        png_apply_specific_filter_8(best_nr, dest, src, width);
      else
        png_apply_specific_filter_32(best_nr, dest, src, width);
-     free(pairs);
      return best_nr;
  }
  
@@@ -1458,6 -1528,8 +1528,6 @@@ EXPORT void savePNG(const char*filename
      unsigned char format;
      unsigned char tmp;
      unsigned char* data2=0;
 -    u32 datalen;
 -    u32 datalen2;
      unsigned char head[] = {137,80,78,71,13,10,26,10}; // PNG header
      int cols;
      char alpha = 1;
@@@ -1494,6 -1566,8 +1564,6 @@@
          png_quantize_image(data, width*height, numcolors, &data, palette);
      }
  
 -    datalen = (width*height*bpp/8+cols*8);
 -    
      fi = fopen(filename, "wb");
      if(!fi) {
        perror("open");