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#include <stdlib.h>
#include "sequence_formats.h"
/* routines for scrambling a sequence */
/*
send seq of length seq_len
put in a scramble structure
generate seq_len random numbers and
put them into the scramble structure
sort the scramble structure
copy the scrambled sequence to seq
*/
struct char_int_pair {
char character;
int number;
};
int compare_pair(const void *vp1, const void *vp2) {
struct char_int_pair *p1 = (struct char_int_pair *)vp1;
struct char_int_pair *p2 = (struct char_int_pair *)vp2;
if (p1->number < p2->number)
return -1;
else if (p1->number == p2->number)
return 0;
else
return 1;
}
int scramble_seq ( char seq[], int seq_len, int seed ) {
int i;
struct char_int_pair *scrambler;
if ( ! ( scrambler = (struct char_int_pair *) malloc ( sizeof(struct char_int_pair)*(seq_len) ))) {
return -1;
}
srand(seed);
for(i=0;i<seq_len;i++) {
scrambler[i].character = seq[i];
scrambler[i].number = rand();
}
qsort ((void *) scrambler, seq_len, sizeof(struct char_int_pair),
compare_pair);
for(i=0;i<seq_len;i++) {
seq[i] = scrambler[i].character;
}
free ( scrambler );
return 0;
}
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