Revision 55672a39b4e0f82e6f997879724ea37ca7e0d765 authored by Junio C Hamano on 09 May 2016, 18:36:09 UTC, committed by Junio C Hamano on 09 May 2016, 19:32:42 UTC
We never used the "letters" form since we came up with "test_seq" to replace use of non-portable "seq" in our test script, which we introduced it at d17cf5f3 (tests: Introduce test_seq, 2012-08-04). We use this helper to either iterate for N times (i.e. the values on the lines do not even matter), or just to get N distinct strings (i.e. the values on the lines themselves do not really matter, but we care that they are different from each other and reproducible). Stop promising that we may allow using "letters"; this would open an easier reimplementation that does not rely on $PERL, if somebody later wants to. Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 7654286
mergesort.c
#include "cache.h"
#include "mergesort.h"
struct mergesort_sublist {
void *ptr;
unsigned long len;
};
static void *get_nth_next(void *list, unsigned long n,
void *(*get_next_fn)(const void *))
{
while (n-- && list)
list = get_next_fn(list);
return list;
}
static void *pop_item(struct mergesort_sublist *l,
void *(*get_next_fn)(const void *))
{
void *p = l->ptr;
l->ptr = get_next_fn(l->ptr);
l->len = l->ptr ? (l->len - 1) : 0;
return p;
}
void *llist_mergesort(void *list,
void *(*get_next_fn)(const void *),
void (*set_next_fn)(void *, void *),
int (*compare_fn)(const void *, const void *))
{
unsigned long l;
if (!list)
return NULL;
for (l = 1; ; l *= 2) {
void *curr;
struct mergesort_sublist p, q;
p.ptr = list;
q.ptr = get_nth_next(p.ptr, l, get_next_fn);
if (!q.ptr)
break;
p.len = q.len = l;
if (compare_fn(p.ptr, q.ptr) > 0)
list = curr = pop_item(&q, get_next_fn);
else
list = curr = pop_item(&p, get_next_fn);
while (p.ptr) {
while (p.len || q.len) {
void *prev = curr;
if (!p.len)
curr = pop_item(&q, get_next_fn);
else if (!q.len)
curr = pop_item(&p, get_next_fn);
else if (compare_fn(p.ptr, q.ptr) > 0)
curr = pop_item(&q, get_next_fn);
else
curr = pop_item(&p, get_next_fn);
set_next_fn(prev, curr);
}
p.ptr = q.ptr;
p.len = l;
q.ptr = get_nth_next(p.ptr, l, get_next_fn);
q.len = q.ptr ? l : 0;
}
set_next_fn(curr, NULL);
}
return list;
}
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