static int diff(struct line *a, int an, struct line *b, int bn,
struct hunk *base)
{
struct hunk *curr;
struct pos *pos;
int t, count = 0;
/* allocate and fill arrays */
t = equatelines(a, an, b, bn);
pos = (struct pos *)calloc(bn ? bn : 1, sizeof(struct pos));
if (pos && t) {
/* generate the matching block list */
curr = recurse(a, b, pos, 0, an, 0, bn, base);
if (!curr)
return -1;
/* sentinel end hunk */
curr->next = (struct hunk *)malloc(sizeof(struct hunk));
if (!curr->next)
return -1;
curr = curr->next;
curr->a1 = curr->a2 = an;
curr->b1 = curr->b2 = bn;
curr->next = NULL;
}
free(pos);
/* normalize the hunk list, try to push each hunk towards the end */
for (curr = base->next; curr; curr = curr->next) {
struct hunk *next = curr->next;
int shift = 0;
if (!next)
break;
if (curr->a2 == next->a1)
while (curr->a2 + shift < an && curr->b2 + shift < bn
&& !cmp(a + curr->a2 + shift,
b + curr->b2 + shift))
shift++;
else if (curr->b2 == next->b1)
while (curr->b2 + shift < bn && curr->a2 + shift < an
&& !cmp(b + curr->b2 + shift,
a + curr->a2 + shift))
shift++;
if (!shift)
continue;
curr->b2 += shift;
next->b1 += shift;
curr->a2 += shift;
next->a1 += shift;
}
for (curr = base->next; curr; curr = curr->next)
count++;
return count;
}
static struct hunklist diff(struct line *a, int an, struct line *b, int bn)
{
struct hunklist l;
struct hunk *curr;
struct pos *pos;
int t;
/* allocate and fill arrays */
t = equatelines(a, an, b, bn);
pos = (struct pos *)calloc(bn ? bn : 1, sizeof(struct pos));
/* we can't have more matches than lines in the shorter file */
l.head = l.base = (struct hunk *)malloc(sizeof(struct hunk) *
((an<bn ? an:bn) + 1));
if (pos && l.base && t) {
/* generate the matching block list */
recurse(a, b, pos, 0, an, 0, bn, &l);
l.head->a1 = l.head->a2 = an;
l.head->b1 = l.head->b2 = bn;
l.head++;
}
free(pos);
/* normalize the hunk list, try to push each hunk towards the end */
for (curr = l.base; curr != l.head; curr++) {
struct hunk *next = curr+1;
int shift = 0;
if (next == l.head)
break;
if (curr->a2 == next->a1)
while (curr->a2+shift < an && curr->b2+shift < bn
&& !cmp(a+curr->a2+shift, b+curr->b2+shift))
shift++;
else if (curr->b2 == next->b1)
while (curr->b2+shift < bn && curr->a2+shift < an
&& !cmp(b+curr->b2+shift, a+curr->a2+shift))
shift++;
if (!shift)
continue;
curr->b2 += shift;
next->b1 += shift;
curr->a2 += shift;
next->a1 += shift;
}
return l;
}