git/t/helper/test-mergesort.c
Elijah Newren 5e3f94dfe3 treewide: remove cache.h inclusion due to previous changes
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-24 12:47:33 -07:00

407 lines
8.2 KiB
C
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#include "test-tool.h"
#include "mem-pool.h"
#include "mergesort.h"
#include "strbuf.h"
static uint32_t minstd_rand(uint32_t *state)
{
*state = (uint64_t)*state * 48271 % 2147483647;
return *state;
}
struct line {
char *text;
struct line *next;
};
DEFINE_LIST_SORT(static, sort_lines, struct line, next);
static int compare_strings(const struct line *x, const struct line *y)
{
return strcmp(x->text, y->text);
}
static int sort_stdin(void)
{
struct line *lines;
struct line **tail = &lines;
struct strbuf sb = STRBUF_INIT;
struct mem_pool lines_pool;
char *p;
strbuf_read(&sb, 0, 0);
/*
* Split by newline, but don't create an item
* for the empty string after the last separator.
*/
if (sb.len && sb.buf[sb.len - 1] == '\n')
strbuf_setlen(&sb, sb.len - 1);
mem_pool_init(&lines_pool, 0);
p = sb.buf;
for (;;) {
char *eol = strchr(p, '\n');
struct line *line = mem_pool_alloc(&lines_pool, sizeof(*line));
line->text = p;
*tail = line;
tail = &line->next;
if (!eol)
break;
*eol = '\0';
p = eol + 1;
}
*tail = NULL;
sort_lines(&lines, compare_strings);
while (lines) {
puts(lines->text);
lines = lines->next;
}
return 0;
}
static void dist_sawtooth(int *arr, int n, int m)
{
int i;
for (i = 0; i < n; i++)
arr[i] = i % m;
}
static void dist_rand(int *arr, int n, int m)
{
int i;
uint32_t seed = 1;
for (i = 0; i < n; i++)
arr[i] = minstd_rand(&seed) % m;
}
static void dist_stagger(int *arr, int n, int m)
{
int i;
for (i = 0; i < n; i++)
arr[i] = (i * m + i) % n;
}
static void dist_plateau(int *arr, int n, int m)
{
int i;
for (i = 0; i < n; i++)
arr[i] = (i < m) ? i : m;
}
static void dist_shuffle(int *arr, int n, int m)
{
int i, j, k;
uint32_t seed = 1;
for (i = j = 0, k = 1; i < n; i++)
arr[i] = minstd_rand(&seed) % m ? (j += 2) : (k += 2);
}
#define DIST(name) { #name, dist_##name }
static struct dist {
const char *name;
void (*fn)(int *arr, int n, int m);
} dist[] = {
DIST(sawtooth),
DIST(rand),
DIST(stagger),
DIST(plateau),
DIST(shuffle),
};
static const struct dist *get_dist_by_name(const char *name)
{
int i;
for (i = 0; i < ARRAY_SIZE(dist); i++) {
if (!strcmp(dist[i].name, name))
return &dist[i];
}
return NULL;
}
static void mode_copy(int *arr, int n)
{
/* nothing */
}
static void mode_reverse(int *arr, int n)
{
int i, j;
for (i = 0, j = n - 1; i < j; i++, j--)
SWAP(arr[i], arr[j]);
}
static void mode_reverse_1st_half(int *arr, int n)
{
mode_reverse(arr, n / 2);
}
static void mode_reverse_2nd_half(int *arr, int n)
{
int half = n / 2;
mode_reverse(arr + half, n - half);
}
static int compare_ints(const void *av, const void *bv)
{
const int *ap = av, *bp = bv;
int a = *ap, b = *bp;
return (a > b) - (a < b);
}
static void mode_sort(int *arr, int n)
{
QSORT(arr, n, compare_ints);
}
static void mode_dither(int *arr, int n)
{
int i;
for (i = 0; i < n; i++)
arr[i] += i % 5;
}
static void unriffle(int *arr, int n, int *tmp)
{
int i, j;
COPY_ARRAY(tmp, arr, n);
for (i = j = 0; i < n; i += 2)
arr[j++] = tmp[i];
for (i = 1; i < n; i += 2)
arr[j++] = tmp[i];
}
static void unriffle_recursively(int *arr, int n, int *tmp)
{
if (n > 1) {
int half = n / 2;
unriffle(arr, n, tmp);
unriffle_recursively(arr, half, tmp);
unriffle_recursively(arr + half, n - half, tmp);
}
}
static void mode_unriffle(int *arr, int n)
{
int *tmp;
ALLOC_ARRAY(tmp, n);
unriffle_recursively(arr, n, tmp);
free(tmp);
}
static unsigned int prev_pow2(unsigned int n)
{
unsigned int pow2 = 1;
while (pow2 * 2 < n)
pow2 *= 2;
return pow2;
}
static void unriffle_recursively_skewed(int *arr, int n, int *tmp)
{
if (n > 1) {
int pow2 = prev_pow2(n);
int rest = n - pow2;
unriffle(arr + pow2 - rest, rest * 2, tmp);
unriffle_recursively_skewed(arr, pow2, tmp);
unriffle_recursively_skewed(arr + pow2, rest, tmp);
}
}
static void mode_unriffle_skewed(int *arr, int n)
{
int *tmp;
ALLOC_ARRAY(tmp, n);
unriffle_recursively_skewed(arr, n, tmp);
free(tmp);
}
#define MODE(name) { #name, mode_##name }
static struct mode {
const char *name;
void (*fn)(int *arr, int n);
} mode[] = {
MODE(copy),
MODE(reverse),
MODE(reverse_1st_half),
MODE(reverse_2nd_half),
MODE(sort),
MODE(dither),
MODE(unriffle),
MODE(unriffle_skewed),
};
static const struct mode *get_mode_by_name(const char *name)
{
int i;
for (i = 0; i < ARRAY_SIZE(mode); i++) {
if (!strcmp(mode[i].name, name))
return &mode[i];
}
return NULL;
}
static int generate(int argc, const char **argv)
{
const struct dist *dist = NULL;
const struct mode *mode = NULL;
int i, n, m, *arr;
if (argc != 4)
return 1;
dist = get_dist_by_name(argv[0]);
mode = get_mode_by_name(argv[1]);
n = strtol(argv[2], NULL, 10);
m = strtol(argv[3], NULL, 10);
if (!dist || !mode)
return 1;
ALLOC_ARRAY(arr, n);
dist->fn(arr, n, m);
mode->fn(arr, n);
for (i = 0; i < n; i++)
printf("%08x\n", arr[i]);
free(arr);
return 0;
}
static struct stats {
int get_next, set_next, compare;
} stats;
struct number {
int value, rank;
struct number *next;
};
DEFINE_LIST_SORT_DEBUG(static, sort_numbers, struct number, next,
stats.get_next++, stats.set_next++);
static int compare_numbers(const struct number *an, const struct number *bn)
{
int a = an->value, b = bn->value;
stats.compare++;
return (a > b) - (a < b);
}
static void clear_numbers(struct number *list)
{
while (list) {
struct number *next = list->next;
free(list);
list = next;
}
}
static int test(const struct dist *dist, const struct mode *mode, int n, int m)
{
int *arr;
size_t i;
struct number *curr, *list, **tail;
int is_sorted = 1;
int is_stable = 1;
const char *verdict;
int result = -1;
ALLOC_ARRAY(arr, n);
dist->fn(arr, n, m);
mode->fn(arr, n);
for (i = 0, tail = &list; i < n; i++) {
curr = xmalloc(sizeof(*curr));
curr->value = arr[i];
curr->rank = i;
*tail = curr;
tail = &curr->next;
}
*tail = NULL;
stats.get_next = stats.set_next = stats.compare = 0;
sort_numbers(&list, compare_numbers);
QSORT(arr, n, compare_ints);
for (i = 0, curr = list; i < n && curr; i++, curr = curr->next) {
if (arr[i] != curr->value)
is_sorted = 0;
if (curr->next && curr->value == curr->next->value &&
curr->rank >= curr->next->rank)
is_stable = 0;
}
if (i < n) {
verdict = "too short";
} else if (curr) {
verdict = "too long";
} else if (!is_sorted) {
verdict = "not sorted";
} else if (!is_stable) {
verdict = "unstable";
} else {
verdict = "OK";
result = 0;
}
printf("%-9s %-16s %8d %8d %8d %8d %8d %s\n",
dist->name, mode->name, n, m, stats.get_next, stats.set_next,
stats.compare, verdict);
clear_numbers(list);
free(arr);
return result;
}
/*
* A version of the qsort certification program from "Engineering a Sort
* Function" by Bentley and McIlroy, Software—Practice and Experience,
* Volume 23, Issue 11, 12491265 (November 1993).
*/
static int run_tests(int argc, const char **argv)
{
const char *argv_default[] = { "100", "1023", "1024", "1025" };
if (!argc)
return run_tests(ARRAY_SIZE(argv_default), argv_default);
printf("%-9s %-16s %8s %8s %8s %8s %8s %s\n",
"distribut", "mode", "n", "m", "get_next", "set_next",
"compare", "verdict");
while (argc--) {
int i, j, m, n = strtol(*argv++, NULL, 10);
for (i = 0; i < ARRAY_SIZE(dist); i++) {
for (j = 0; j < ARRAY_SIZE(mode); j++) {
for (m = 1; m < 2 * n; m *= 2) {
if (test(&dist[i], &mode[j], n, m))
return 1;
}
}
}
}
return 0;
}
int cmd__mergesort(int argc, const char **argv)
{
int i;
const char *sep;
if (argc == 6 && !strcmp(argv[1], "generate"))
return generate(argc - 2, argv + 2);
if (argc == 2 && !strcmp(argv[1], "sort"))
return sort_stdin();
if (argc > 1 && !strcmp(argv[1], "test"))
return run_tests(argc - 2, argv + 2);
fprintf(stderr, "usage: test-tool mergesort generate <distribution> <mode> <n> <m>\n");
fprintf(stderr, " or: test-tool mergesort sort\n");
fprintf(stderr, " or: test-tool mergesort test [<n>...]\n");
fprintf(stderr, "\n");
for (i = 0, sep = "distributions: "; i < ARRAY_SIZE(dist); i++, sep = ", ")
fprintf(stderr, "%s%s", sep, dist[i].name);
fprintf(stderr, "\n");
for (i = 0, sep = "modes: "; i < ARRAY_SIZE(mode); i++, sep = ", ")
fprintf(stderr, "%s%s", sep, mode[i].name);
fprintf(stderr, "\n");
return 129;
}