int d, sn, i;
struct varray *ses = varray_new(sizeof(struct diff_edit), NULL);
d = diff(a, 0, n, b, 0, m, NULL, NULL, NULL, 0, ses, &sn, NULL);
for (i = 0; i < sn; i++) {
struct diff_edit *e = varray_get(ses, i);
switch (e->op) {
case DIFF_MATCH:
printf("MAT: ");
fwrite(a + e->off, 1, e->len, stdout);
break;
case DIFF_DELETE:
printf("DEL: ");
fwrite(a + e->off, 1, e->len, stdout);
break;
case DIFF_INSERT:
printf("INS: ");
fwrite(b + e->off, 1, e->len, stdout);
break;
}
printf("\n");
}
varray_del(ses);
Diff definitions
typedef const void *(*idx_fn)(const void *s, int idx, void *context);
typedef int (*cmp_fn)(const void *e1, const void *e2, void *context);
typedef enum {
DIFF_MATCH = 1,
DIFF_DELETE,
DIFF_INSERT
} diff_op;
struct diff_edit {
short op; /* DIFF_MATCH, DIFF_DELETE or DIFF_INSERT */
int off; /* off into a if MATCH or DELETE, b if INSERT */
int len;
};
The idx_fn is a pointer to a function that returns the element the numeric index specified by idx in the sequence s. The cmp_fn (actually defined in hashmap (3m)) is a pointer to a function that returns zero if the sequence elements e1 and e2 are equal and non-zero otherwise. The context parameter specified with the diff call is always supplied to both callbacks.
Each element in the ses varray is a struct diff_edit structure and represents an individual match, delete, or insert operation in the edit script. The op member is DIFF_MATCH, DIFF_DELETE or DIFF_INSERT. The off and len members indicate the offset and length of the subsequence that matches or should be deleted from sequence a or inserted from sequence b.
int diff(const void *a, int aoff, int n, const void *b, int boff, int m, idx_fn idx, cmp_fn cmp, void *context, int dmax, struct varray *ses, int *sn, struct varray *buf);