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Merge branch 'rs/mergesort' 

Make our mergesort implementation type-safe.

* rs/mergesort:
  mergesort: remove llist_mergesort()
  packfile: use DEFINE_LIST_SORT
  fetch-pack: use DEFINE_LIST_SORT
  commit: use DEFINE_LIST_SORT
  blame: use DEFINE_LIST_SORT
  test-mergesort: use DEFINE_LIST_SORT
  test-mergesort: use DEFINE_LIST_SORT_DEBUG
  mergesort: add macros for typed sort of linked lists
  mergesort: tighten merge loop
  mergesort: unify ranks loops
This commit is contained in:
Junio C Hamano 2022-08-03 13:36:09 -07:00
parent 87098a047b 0f1eb7d6e9
commit 4e0d160bbc
12 changed files with 134 additions and 199 deletions
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1
Makefile
View File

@ -992,7 +992,6 @@ LIB_OBJS += merge-ort.o
LIB_OBJS += merge-ort-wrappers.o
LIB_OBJS += merge-recursive.o
LIB_OBJS += merge.o
LIB_OBJS += mergesort.o
LIB_OBJS += midx.o
LIB_OBJS += name-hash.o
LIB_OBJS += negotiator/default.o

30
blame.c
View File

@ -1098,30 +1098,22 @@ static struct blame_entry *blame_merge(struct blame_entry *list1,
}
}
static void *get_next_blame(const void *p)
{
return ((struct blame_entry *)p)->next;
}
static void set_next_blame(void *p1, void *p2)
{
((struct blame_entry *)p1)->next = p2;
}
DEFINE_LIST_SORT(static, sort_blame_entries, struct blame_entry, next);
/*
* Final image line numbers are all different, so we don't need a
* three-way comparison here.
*/
static int compare_blame_final(const void *p1, const void *p2)
static int compare_blame_final(const struct blame_entry *e1,
const struct blame_entry *e2)
{
return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
? 1 : -1;
return e1->lno > e2->lno ? 1 : -1;
}
static int compare_blame_suspect(const void *p1, const void *p2)
static int compare_blame_suspect(const struct blame_entry *s1,
const struct blame_entry *s2)
{
const struct blame_entry *s1 = p1, *s2 = p2;
/*
* to allow for collating suspects, we sort according to the
* respective pointer value as the primary sorting criterion.
@ -1138,8 +1130,7 @@ static int compare_blame_suspect(const void *p1, const void *p2)
void blame_sort_final(struct blame_scoreboard *sb)
{
sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame,
compare_blame_final);
sort_blame_entries(&sb->ent, compare_blame_final);
}
static int compare_commits_by_reverse_commit_date(const void *a,
@ -1964,9 +1955,7 @@ static void pass_blame_to_parent(struct blame_scoreboard *sb,
parent, target, 0);
*d.dstq = NULL;
if (ignore_diffs)
newdest = llist_mergesort(newdest, get_next_blame,
set_next_blame,
compare_blame_suspect);
sort_blame_entries(&newdest, compare_blame_suspect);
queue_blames(sb, parent, newdest);
return;
@ -2383,8 +2372,7 @@ static int num_scapegoats(struct rev_info *revs, struct commit *commit, int reve
*/
static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed)
{
blamed = llist_mergesort(blamed, get_next_blame, set_next_blame,
compare_blame_suspect);
sort_blame_entries(&blamed, compare_blame_suspect);
while (blamed)
{
struct blame_origin *porigin = blamed->suspect;

20
commit.c
View File

@ -642,10 +642,11 @@ struct commit_list * commit_list_insert_by_date(struct commit *item, struct comm
return commit_list_insert(item, pp);
}
static int commit_list_compare_by_date(const void *a, const void *b)
static int commit_list_compare_by_date(const struct commit_list *a,
const struct commit_list *b)
{
timestamp_t a_date = ((const struct commit_list *)a)->item->date;
timestamp_t b_date = ((const struct commit_list *)b)->item->date;
timestamp_t a_date = a->item->date;
timestamp_t b_date = b->item->date;
if (a_date < b_date)
return 1;
if (a_date > b_date)
@ -653,20 +654,11 @@ static int commit_list_compare_by_date(const void *a, const void *b)
return 0;
}
static void *commit_list_get_next(const void *a)
{
return ((const struct commit_list *)a)->next;
}
static void commit_list_set_next(void *a, void *next)
{
((struct commit_list *)a)->next = next;
}
DEFINE_LIST_SORT(static, commit_list_sort, struct commit_list, next);
void commit_list_sort_by_date(struct commit_list **list)
{
*list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
commit_list_compare_by_date);
commit_list_sort(list, commit_list_compare_by_date);
}
struct commit *pop_most_recent_commit(struct commit_list **list,

8
fetch-pack.c
View File

@ -26,6 +26,7 @@
#include "commit-reach.h"
#include "commit-graph.h"
#include "sigchain.h"
#include "mergesort.h"
static int transfer_unpack_limit = -1;
static int fetch_unpack_limit = -1;
@ -1025,6 +1026,13 @@ static int get_pack(struct fetch_pack_args *args,
return 0;
}
static int ref_compare_name(const struct ref *a, const struct ref *b)
{
return strcmp(a->name, b->name);
}
DEFINE_LIST_SORT(static, sort_ref_list, struct ref, next);
static int cmp_ref_by_name(const void *a_, const void *b_)
{
const struct ref *a = *((const struct ref **)a_);

84
mergesort.c
View File

@ -1,84 +0,0 @@
#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;
}

108
mergesort.h
View File

@ -1,17 +1,105 @@
#ifndef MERGESORT_H
#define MERGESORT_H
/* Combine two sorted lists. Take from `list` on equality. */
#define DEFINE_LIST_MERGE_INTERNAL(name, type) \
static type *name##__merge(type *list, type *other, \
int (*compare_fn)(const type *, const type *))\
{ \
type *result = list, *tail; \
int prefer_list = compare_fn(list, other) <= 0; \
\
if (!prefer_list) { \
result = other; \
SWAP(list, other); \
} \
for (;;) { \
do { \
tail = list; \
list = name##__get_next(list); \
if (!list) { \
name##__set_next(tail, other); \
return result; \
} \
} while (compare_fn(list, other) < prefer_list); \
name##__set_next(tail, other); \
prefer_list ^= 1; \
SWAP(list, other); \
} \
}
/*
* Sort linked list in place.
* - get_next_fn() returns the next element given an element of a linked list.
* - set_next_fn() takes two elements A and B, and makes B the "next" element
* of A on the list.
* - compare_fn() takes two elements A and B, and returns negative, 0, positive
* as the same sign as "subtracting" B from A.
* 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 *));
#define DEFINE_LIST_SORT_INTERNAL(scope, name, type) \
scope void name(type **listp, \
int (*compare_fn)(const type *, const type *)) \
{ \
type *list = *listp; \
type *ranks[bitsizeof(type *)]; \
size_t n = 0; \
\
if (!list) \
return; \
\
for (;;) { \
int i; \
size_t m; \
type *next = name##__get_next(list); \
if (next) \
name##__set_next(list, NULL); \
for (i = 0, m = n;; i++, m >>= 1) { \
if (m & 1) { \
list = name##__merge(ranks[i], list, \
compare_fn); \
} else if (next) { \
break; \
} else if (!m) { \
*listp = list; \
return; \
} \
} \
n++; \
ranks[i] = list; \
list = next; \
} \
}
#define DECLARE_LIST_SORT(scope, name, type) \
scope void name(type **listp, \
int (*compare_fn)(const type *, const type *))
#define DEFINE_LIST_SORT_DEBUG(scope, name, type, next_member, \
on_get_next, on_set_next) \
\
static inline type *name##__get_next(const type *elem) \
{ \
on_get_next; \
return elem->next_member; \
} \
\
static inline void name##__set_next(type *elem, type *next) \
{ \
on_set_next; \
elem->next_member = next; \
} \
\
DEFINE_LIST_MERGE_INTERNAL(name, type) \
DEFINE_LIST_SORT_INTERNAL(scope, name, type) \
DECLARE_LIST_SORT(scope, name, type)
#define DEFINE_LIST_SORT(scope, name, type, next_member) \
DEFINE_LIST_SORT_DEBUG(scope, name, type, next_member, (void)0, (void)0)
#endif

18
packfile.c
View File

@ -941,20 +941,10 @@ unsigned long repo_approximate_object_count(struct repository *r)
return r->objects->approximate_object_count;
}
static void *get_next_packed_git(const void *p)
{
return ((const struct packed_git *)p)->next;
}
DEFINE_LIST_SORT(static, sort_packs, struct packed_git, next);
static void set_next_packed_git(void *p, void *next)
static int sort_pack(const struct packed_git *a, const struct packed_git *b)
{
((struct packed_git *)p)->next = next;
}
static int sort_pack(const void *a_, const void *b_)
{
const struct packed_git *a = a_;
const struct packed_git *b = b_;
int st;
/*
@ -981,9 +971,7 @@ static int sort_pack(const void *a_, const void *b_)
static void rearrange_packed_git(struct repository *r)
{
r->objects->packed_git = llist_mergesort(
r->objects->packed_git, get_next_packed_git,
set_next_packed_git, sort_pack);
sort_packs(&r->objects->packed_git, sort_pack);
}
static void prepare_packed_git_mru(struct repository *r)

22
remote.c
View File

@ -11,7 +11,6 @@
#include "dir.h"
#include "tag.h"
#include "string-list.h"
#include "mergesort.h"
#include "strvec.h"
#include "commit-reach.h"
#include "advice.h"
@ -1082,27 +1081,6 @@ void free_refs(struct ref *ref)
}
}
int ref_compare_name(const void *va, const void *vb)
{
const struct ref *a = va, *b = vb;
return strcmp(a->name, b->name);
}
static void *ref_list_get_next(const void *a)
{
return ((const struct ref *)a)->next;
}
static void ref_list_set_next(void *a, void *next)
{
((struct ref *)a)->next = next;
}
void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
{
*l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
}
int count_refspec_match(const char *pattern,
struct ref *refs,
struct ref **matched_ref)

2
remote.h
View File

@ -207,9 +207,7 @@ struct ref *find_ref_by_name(const struct ref *list, const char *name);
struct ref *alloc_ref(const char *name);
struct ref *copy_ref(const struct ref *ref);
struct ref *copy_ref_list(const struct ref *ref);
void sort_ref_list(struct ref **, int (*cmp)(const void *, const void *));
int count_refspec_match(const char *, struct ref *refs, struct ref **matched_ref);
int ref_compare_name(const void *, const void *);
int check_ref_type(const struct ref *ref, int flags);

34
t/helper/test-mergesort.c
View File

@ -13,19 +13,10 @@ struct line {
struct line *next;
};
static void *get_next(const void *a)
{
return ((const struct line *)a)->next;
}
DEFINE_LIST_SORT(static, sort_lines, struct line, next);
static void set_next(void *a, void *b)
static int compare_strings(const struct line *x, const struct line *y)
{
((struct line *)a)->next = b;
}
static int compare_strings(const void *a, const void *b)
{
const struct line *x = a, *y = b;
return strcmp(x->text, y->text);
}
@ -47,7 +38,7 @@ static int sort_stdin(void)
p = line;
}
lines = llist_mergesort(lines, get_next, set_next, compare_strings);
sort_lines(&lines, compare_strings);
while (lines) {
puts(lines->text);
@ -273,21 +264,11 @@ struct number {
struct number *next;
};
static void *get_next_number(const void *a)
{
stats.get_next++;
return ((const struct number *)a)->next;
}
DEFINE_LIST_SORT_DEBUG(static, sort_numbers, struct number, next,
stats.get_next++, stats.set_next++);
static void set_next_number(void *a, void *b)
static int compare_numbers(const struct number *an, const struct number *bn)
{
stats.set_next++;
((struct number *)a)->next = b;
}
static int compare_numbers(const void *av, const void *bv)
{
const struct number *an = av, *bn = bv;
int a = an->value, b = bn->value;
stats.compare++;
return (a > b) - (a < b);
@ -325,8 +306,7 @@ static int test(const struct dist *dist, const struct mode *mode, int n, int m)
*tail = NULL;
stats.get_next = stats.set_next = stats.compare = 0;
list = llist_mergesort(list, get_next_number, set_next_number,
compare_numbers);
sort_numbers(&list, compare_numbers);
QSORT(arr, n, compare_ints);
for (i = 0, curr = list; i < n && curr; i++, curr = curr->next) {

4
t/perf/p0071-sort.sh
View File

@ -40,11 +40,11 @@ done
for file in unsorted sorted reversed
do
test_perf "llist_mergesort() $file" "
test_perf "DEFINE_LIST_SORT $file" "
test-tool mergesort sort <$file >actual
"
test_expect_success "llist_mergesort() $file sorts like sort(1)" "
test_expect_success "DEFINE_LIST_SORT $file sorts like sort(1)" "
test_cmp_bin sorted actual
"
done

2
t/t0071-sort.sh
View File

@ -5,7 +5,7 @@ test_description='verify sort functions'
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
test_expect_success 'llist_mergesort()' '
test_expect_success 'DEFINE_LIST_SORT_DEBUG' '
test-tool mergesort test
'