bl2exp.c

   1 /*
   2  * bl2exp, extract blast E-values from blastp output
   3  *
   4  * Copyright (C) 2012 Ali Gholami Rudi <ali at rudi dot ir>
   5  *
   6  * This program is released under the modified BSD license.
   7  */
   8 #include <ctype.h>
   9 #include <stdio.h>
  10 #include <string.h>
  11
  12 #define ETHRESH         0.001
  13
  14 static char *readword(char *d, char *s)
  15 {
  16         while (isspace(*s))
  17                 s++;
  18         while (*s && !isspace(*s))
  19                 *d++ = *s++;
  20         *d = '\0';
  21         return s;
  22 }
  23
  24 static int readentries(void)
  25 {
  26         char line[1024];
  27         char query[128];
  28         char other[128];
  29         char s_score[128];
  30         int junk;
  31         double score;
  32         while (1) {
  33                 if (!fgets(line, sizeof(line), stdin))
  34                         return 1;
  35                 if (!strncmp(line, "Query= ", 6)) {
  36                         readword(query, line + 7);
  37                         break;
  38                 }
  39         }
  40         while (1) {
  41                 if (!fgets(line, sizeof(line), stdin))
  42                         return 1;
  43                 if (!strncmp(line, "Sequences producing", 16))
  44                         break;
  45                 if (!strncmp(line, " ***** No hits found", 16))
  46                         return 0;
  47         }
  48         fgets(line, sizeof(line), stdin);
  49         while (1) {
  50                 if (!fgets(line, sizeof(line), stdin))
  51                         return 1;
  52                 if (sscanf(line, "%s %d %s", other, &junk, s_score) != 3)
  53                         break;
  54                 sprintf(line, "%s%s", s_score[0] == 'e' ? "1" : "", s_score);
  55                 sscanf(line, "%lf", &score);
  56                 if (score < ETHRESH)
  57                         printf("%s\t%s\t%lg\n", query, other, score);
  58         }
  59         return 0;
  60 }
  61
  62 int main(int argc, char *argv[])
  63 {
  64         if (argc > 1) {
  65                 printf("usage: %s <blast >e_values\n", argv[0]);
  66                 return 0;
  67         }
  68         while (!readentries())
  69                 ;
  70         return 0;
  71 }