bird.c

   1 #include "code.h"
   2
   3 unsigned int bird( char **text, char **pattern, int m, int n )
   4 {
   5         /* x and y can be -1 */
   6         int x, y;
   7
   8         unsigned int i, row, matches = 0;
   9
  10         /* Iterate rows */
  11         for ( row = 0; row < n - m + 1; row++ ) {
  12
  13                 x = 0;
  14
  15                 /* Iterate through results on the same row */
  16                 while ( x != -1 ) {
  17
  18                         x = aho( text, pattern, m, n, row, x, 0, n - m + 1 );
  19
  20                         /* If a row is found, check the m - 1 rows underneath it for matches */
  21                         if ( x != -1 ) {
  22
  23                                 for ( i = 1; i < m; i++) {
  24                                         /* Optimization: instead of checking against n chars on
  25                                          subsequent rows, just check against the next m chars after x */
  26                                         y = aho( text, pattern, m, n, row + i, x, i, x + m );
  27
  28                                         if ( y != x )
  29                                                 break;
  30
  31                                         /* If we reached to the final line above x without breaking, we have a match */
  32                                         else if ( i == m -1)
  33                                                 matches++;
  34                                 }
  35                                 /* After each attempt,increase the counter + 1 */
  36                                 x++;
  37                         }
  38                 }
  39         }
  40         return matches;
  41 }