+/* Copyright (C) 2011 by Valentin Ochs
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/* Minor changes by Rich Felker for integration in musl, 2011-04-27. */
+
+#include <stdint.h>
#include <stdlib.h>
#include <string.h>
-/* A simple heap sort implementation.. only in-place O(nlogn) sort I know. */
+#include "atomic.h"
+#define ntz(x) a_ctz_l((x))
-#define MIN(a, b) ((a)<(b) ? (a) : (b))
+typedef int (*cmpfun)(const void *, const void *);
+
+static inline int pntz(size_t p[2]) {
+ int r = ntz(p[0] - 1);
+ if(r != 0 || (r = 8*sizeof(size_t) + ntz(p[1])) != 8*sizeof(size_t)) {
+ return r;
+ }
+ return 0;
+}
-static void swap(char *a, char *b, size_t len)
+static void cycle(size_t width, unsigned char* ar[], int n)
{
- char tmp[256];
+ unsigned char tmp[256];
size_t l;
- while (len) {
- l = MIN(sizeof tmp, len);
- memcpy(tmp, a, l);
- memcpy(a, b, l);
- memcpy(b, tmp, l);
- a += l;
- b += l;
- len -= l;
+ int i;
+
+ if(n < 2) {
+ return;
+ }
+
+ ar[n] = tmp;
+ while(width) {
+ l = sizeof(tmp) < width ? sizeof(tmp) : width;
+ memcpy(ar[n], ar[0], l);
+ for(i = 0; i < n; i++) {
+ memcpy(ar[i], ar[i + 1], l);
+ ar[i] += l;
+ }
+ width -= l;
+ }
+}
+
+/* shl() and shr() need n > 0 */
+static inline void shl(size_t p[2], int n)
+{
+ if(n >= 8 * sizeof(size_t)) {
+ n -= 8 * sizeof(size_t);
+ p[1] = p[0];
+ p[0] = 0;
+ }
+ p[1] <<= n;
+ p[1] |= p[0] >> (sizeof(size_t) * 8 - n);
+ p[0] <<= n;
+}
+
+static inline void shr(size_t p[2], int n)
+{
+ if(n >= 8 * sizeof(size_t)) {
+ n -= 8 * sizeof(size_t);
+ p[0] = p[1];
+ p[1] = 0;
}
+ p[0] >>= n;
+ p[0] |= p[1] << (sizeof(size_t) * 8 - n);
+ p[1] >>= n;
}
-static void sift(char *base, size_t root, size_t nel, size_t width, int (*cmp)(const void *, const void *))
+static void sift(unsigned char *head, size_t width, cmpfun cmp, int pshift, size_t lp[])
{
- size_t max;
+ unsigned char *rt, *lf;
+ unsigned char *ar[14 * sizeof(size_t) + 1];
+ int i = 1;
+
+ ar[0] = head;
+ while(pshift > 1) {
+ rt = head - width;
+ lf = head - width - lp[pshift - 2];
- while (2*root <= nel) {
- max = 2*root;
- if (max < nel && cmp(base+max*width, base+(max+1)*width) < 0)
- max++;
- if (max && cmp(base+root*width, base+max*width) < 0) {
- swap(base+root*width, base+max*width, width);
- root = max;
- } else break;
+ if((*cmp)(ar[0], lf) >= 0 && (*cmp)(ar[0], rt) >= 0) {
+ break;
+ }
+ if((*cmp)(lf, rt) >= 0) {
+ ar[i++] = lf;
+ head = lf;
+ pshift -= 1;
+ } else {
+ ar[i++] = rt;
+ head = rt;
+ pshift -= 2;
+ }
}
+ cycle(width, ar, i);
}
-void qsort(void *_base, size_t nel, size_t width, int (*cmp)(const void *, const void *))
+static void trinkle(unsigned char *head, size_t width, cmpfun cmp, size_t pp[2], int pshift, int trusty, size_t lp[])
{
- char *base = _base;
- size_t i;
-
- if (!nel) return;
- for (i=(nel+1)/2; i; i--)
- sift(base, i-1, nel-1, width, cmp);
- for (i=nel-1; i; i--) {
- swap(base, base+i*width, width);
- sift(base, 0, i-1, width, cmp);
+ unsigned char *stepson,
+ *rt, *lf;
+ size_t p[2];
+ unsigned char *ar[14 * sizeof(size_t) + 1];
+ int i = 1;
+ int trail;
+
+ p[0] = pp[0];
+ p[1] = pp[1];
+
+ ar[0] = head;
+ while(p[0] != 1 || p[1] != 0) {
+ stepson = head - lp[pshift];
+ if((*cmp)(stepson, ar[0]) <= 0) {
+ break;
+ }
+ if(!trusty && pshift > 1) {
+ rt = head - width;
+ lf = head - width - lp[pshift - 2];
+ if((*cmp)(rt, stepson) >= 0 || (*cmp)(lf, stepson) >= 0) {
+ break;
+ }
+ }
+
+ ar[i++] = stepson;
+ head = stepson;
+ trail = pntz(p);
+ shr(p, trail);
+ pshift += trail;
+ trusty = 0;
+ }
+ if(!trusty) {
+ cycle(width, ar, i);
+ sift(head, width, cmp, pshift, lp);
+ }
+}
+
+void qsort(void *base, size_t nel, size_t width, cmpfun cmp)
+{
+ size_t lp[12*sizeof(size_t)];
+ size_t i, size = width * nel;
+ unsigned char *head = base,
+ *high = head + size - width;
+ size_t p[2] = {1, 0};
+ int pshift = 1;
+ int trail;
+
+ /* Precompute Leonardo numbers, scaled by element width */
+ for(lp[0]=lp[1]=width, i=2; (lp[i]=lp[i-2]+lp[i-1]+width) < size; i++);
+
+ while(head < high) {
+ if((p[0] & 3) == 3) {
+ sift(head, width, cmp, pshift, lp);
+ shr(p, 2);
+ pshift += 2;
+ } else {
+ if(lp[pshift - 1] >= high - head) {
+ trinkle(head, width, cmp, p, pshift, 0, lp);
+ } else {
+ sift(head, width, cmp, pshift, lp);
+ }
+
+ if(pshift == 1) {
+ shl(p, 1);
+ pshift = 0;
+ } else {
+ shl(p, pshift - 1);
+ pshift = 1;
+ }
+ }
+
+ p[0] |= 1;
+ head += width;
+ }
+
+ trinkle(head, width, cmp, p, pshift, 0, lp);
+
+ while(pshift != 1 || p[0] != 1 || p[1] != 0) {
+ if(pshift <= 1) {
+ trail = pntz(p);
+ shr(p, trail);
+ pshift += trail;
+ } else {
+ shl(p, 2);
+ pshift -= 2;
+ p[0] ^= 7;
+ shr(p, 1);
+ trinkle(head - lp[pshift] - width, width, cmp, p, pshift + 1, 1, lp);
+ shl(p, 1);
+ p[0] |= 1;
+ trinkle(head - width, width, cmp, p, pshift, 1, lp);
+ }
+ head -= width;
}
}
projects / oweals / musl.git / commitdiff