mirror of
https://github.com/git/git.git
synced 2024-12-03 23:14:23 +08:00
42c456ff81
Use size_t to match n when building the bitmask for checking whether a rank is occupied, instead of the default signed int. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
#include "cache.h"
|
|
#include "mergesort.h"
|
|
|
|
/* Combine two sorted lists. Take from `list` on equality. */
|
|
static void *llist_merge(void *list, void *other,
|
|
void *(*get_next_fn)(const void *),
|
|
void (*set_next_fn)(void *, void *),
|
|
int (*compare_fn)(const void *, const void *))
|
|
{
|
|
void *result = list, *tail;
|
|
|
|
if (compare_fn(list, other) > 0) {
|
|
result = other;
|
|
goto other;
|
|
}
|
|
for (;;) {
|
|
do {
|
|
tail = list;
|
|
list = get_next_fn(list);
|
|
if (!list) {
|
|
set_next_fn(tail, other);
|
|
return result;
|
|
}
|
|
} while (compare_fn(list, other) <= 0);
|
|
set_next_fn(tail, other);
|
|
other:
|
|
do {
|
|
tail = other;
|
|
other = get_next_fn(other);
|
|
if (!other) {
|
|
set_next_fn(tail, list);
|
|
return result;
|
|
}
|
|
} while (compare_fn(list, other) > 0);
|
|
set_next_fn(tail, list);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Perform an iterative mergesort using an array of sublists.
|
|
*
|
|
* n is the number of items.
|
|
* ranks[i] is undefined if n & 2^i == 0, and assumed empty.
|
|
* ranks[i] contains a sublist of length 2^i otherwise.
|
|
*
|
|
* The number of bits in a void pointer limits the number of objects
|
|
* that can be created, and thus the number of array elements necessary
|
|
* to be able to sort any valid list.
|
|
*
|
|
* Adding an item to this array is like incrementing a binary number;
|
|
* positional values for set bits correspond to sublist lengths.
|
|
*/
|
|
void *llist_mergesort(void *list,
|
|
void *(*get_next_fn)(const void *),
|
|
void (*set_next_fn)(void *, void *),
|
|
int (*compare_fn)(const void *, const void *))
|
|
{
|
|
void *ranks[bitsizeof(void *)];
|
|
size_t n = 0;
|
|
int i;
|
|
|
|
while (list) {
|
|
void *next = get_next_fn(list);
|
|
if (next)
|
|
set_next_fn(list, NULL);
|
|
for (i = 0; n & ((size_t)1 << i); i++)
|
|
list = llist_merge(ranks[i], list, get_next_fn,
|
|
set_next_fn, compare_fn);
|
|
n++;
|
|
ranks[i] = list;
|
|
list = next;
|
|
}
|
|
|
|
for (i = 0; n; i++, n >>= 1) {
|
|
if (!(n & 1))
|
|
continue;
|
|
if (list)
|
|
list = llist_merge(ranks[i], list, get_next_fn,
|
|
set_next_fn, compare_fn);
|
|
else
|
|
list = ranks[i];
|
|
}
|
|
return list;
|
|
}
|