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Make some sorting functions faster

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This commit is contained in:
Justine Tunney 2023-04-24 23:01:36 -07:00
parent 1a839ba41d
commit 614229e3f4
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GPG key ID: BE714B4575D6E328
3 changed files with 86 additions and 26 deletions
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30
libc/str/intsort.c
View file

@ -19,11 +19,26 @@
#include "libc/intrin/strace.internal.h"
#include "libc/runtime/runtime.h"
static void _intsorter(int *A, size_t n) {
static inline void InsertionSort(int *A, long n) {
long i, j, t;
for (i = 1; i < n; i++) {
t = A[i];
j = i - 1;
while (j >= 0 && A[j] > t) {
A[j + 1] = A[j];
j = j - 1;
}
A[j + 1] = t;
}
}
static void IntSort(int *A, long n) {
int t, p;
size_t i, j;
if (n < 2) return;
for (p = A[n / 2], i = 0, j = n - 1;; i++, j--) {
long i, j;
if (n <= 32) {
InsertionSort(A, n);
} else {
for (p = A[n >> 1], i = 0, j = n - 1;; i++, j--) {
while (A[i] < p) i++;
while (A[j] > p) j--;
if (i >= j) break;
@ -31,8 +46,9 @@ static void _intsorter(int *A, size_t n) {
A[i] = A[j];
A[j] = t;
}
_intsorter(A, i);
_intsorter(A + i, n - i);
IntSort(A, i);
IntSort(A + i, n - i);
}
}
/**
@ -40,7 +56,7 @@ static void _intsorter(int *A, size_t n) {
* @see djbsort
*/
void _intsort(int *A, size_t n) {
_intsorter(A, n);
IntSort(A, n);
if (n > 1000) {
STRACE("_intsort(%p, %'zu)", A, n);
}

31
libc/str/longsort.c
View file

@ -19,11 +19,25 @@
#include "libc/intrin/strace.internal.h"
#include "libc/runtime/runtime.h"
static void _longsorter(long *A, size_t n) {
long t, p;
size_t i, j;
if (n < 2) return;
for (p = A[n / 2], i = 0, j = n - 1;; i++, j--) {
static inline void InsertionSort(long *A, long n) {
long i, j, t;
for (i = 1; i < n; i++) {
t = A[i];
j = i - 1;
while (j >= 0 && A[j] > t) {
A[j + 1] = A[j];
j = j - 1;
}
A[j + 1] = t;
}
}
static void LongSort(long *A, long n) {
long t, p, i, j;
if (n <= 32) {
InsertionSort(A, n);
} else {
for (p = A[n >> 1], i = 0, j = n - 1;; i++, j--) {
while (A[i] < p) i++;
while (A[j] > p) j--;
if (i >= j) break;
@ -31,8 +45,9 @@ static void _longsorter(long *A, size_t n) {
A[i] = A[j];
A[j] = t;
}
_longsorter(A, i);
_longsorter(A + i, n - i);
LongSort(A, i);
LongSort(A + i, n - i);
}
}
/**
@ -43,7 +58,7 @@ static void _longsorter(long *A, size_t n) {
*
*/
void _longsort(long *A, size_t n) {
_longsorter(A, n);
LongSort(A, n);
if (n > 1000) {
STRACE("_longsort(%p, %'zu)", A, n);
}

29
test/libc/str/longsort_test.c
View file

@ -53,3 +53,32 @@ BENCH(_longsort, bench) {
EZBENCH2("qsort", memcpy(p2, p1, n * sizeof(long)),
qsort(p2, n, sizeof(long), CompareLong));
}
int CompareInt(const void *a, const void *b) {
const int *x = a;
const int *y = b;
if (*x < *y) return -1;
if (*x > *y) return +1;
return 0;
}
TEST(_intsort, test) {
size_t n = 5000;
int *a = gc(calloc(n, sizeof(int)));
int *b = gc(calloc(n, sizeof(int)));
rngset(a, n * sizeof(int), 0, 0);
memcpy(b, a, n * sizeof(int));
qsort(a, n, sizeof(int), CompareInt);
_intsort(b, n);
ASSERT_EQ(0, memcmp(b, a, n * sizeof(int)));
}
BENCH(_intsort, bench) {
size_t n = 1000;
int *p1 = gc(malloc(n * sizeof(int)));
int *p2 = gc(malloc(n * sizeof(int)));
rngset(p1, n * sizeof(int), 0, 0);
EZBENCH2("_intsort", memcpy(p2, p1, n * sizeof(int)), _intsort(p2, n));
EZBENCH2("qsort", memcpy(p2, p1, n * sizeof(int)),
qsort(p2, n, sizeof(int), CompareInt));
}