[337] | 1 | /* Copyright (C) 2011 by Valentin Ochs
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| 2 | *
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| 3 | * Permission is hereby granted, free of charge, to any person obtaining a copy
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| 4 | * of this software and associated documentation files (the "Software"), to
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| 5 | * deal in the Software without restriction, including without limitation the
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| 6 | * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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| 7 | * sell copies of the Software, and to permit persons to whom the Software is
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| 8 | * furnished to do so, subject to the following conditions:
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| 9 | *
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| 10 | * The above copyright notice and this permission notice shall be included in
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| 11 | * all copies or substantial portions of the Software.
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| 12 | *
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| 13 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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| 14 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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| 15 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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| 16 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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| 17 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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| 18 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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| 19 | * IN THE SOFTWARE.
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| 20 | */
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| 21 |
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| 22 | /* Minor changes by Rich Felker for integration in musl, 2011-04-27. */
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| 23 |
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| 24 | /* Smoothsort, an adaptive variant of Heapsort. Memory usage: O(1).
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| 25 | Run time: Worst case O(n log n), close to O(n) in the mostly-sorted case. */
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| 26 |
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| 27 | #include <stdint.h>
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| 28 | #include <stdlib.h>
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| 29 | #include <string.h>
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| 30 |
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| 31 | #include "atomic.h"
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| 32 | #define ntz(x) a_ctz_l((x))
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| 33 |
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| 34 | typedef int (*cmpfun)(const void *, const void *);
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| 35 |
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| 36 | static inline int pntz(size_t p[2]) {
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| 37 | int r = ntz(p[0] - 1);
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| 38 | if(r != 0 || (r = 8*sizeof(size_t) + ntz(p[1])) != 8*sizeof(size_t)) {
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| 39 | return r;
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| 40 | }
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| 41 | return 0;
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| 42 | }
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| 43 |
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| 44 | static void cycle(size_t width, unsigned char* ar[], int n)
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| 45 | {
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| 46 | unsigned char tmp[256];
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| 47 | size_t l;
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| 48 | int i;
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| 49 |
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| 50 | if(n < 2) {
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| 51 | return;
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| 52 | }
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| 53 |
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| 54 | ar[n] = tmp;
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| 55 | while(width) {
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| 56 | l = sizeof(tmp) < width ? sizeof(tmp) : width;
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| 57 | memcpy(ar[n], ar[0], l);
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| 58 | for(i = 0; i < n; i++) {
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| 59 | memcpy(ar[i], ar[i + 1], l);
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| 60 | ar[i] += l;
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| 61 | }
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| 62 | width -= l;
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| 63 | }
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| 64 | }
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| 65 |
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| 66 | /* shl() and shr() need n > 0 */
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| 67 | static inline void shl(size_t p[2], int n)
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| 68 | {
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| 69 | if(n >= 8 * sizeof(size_t)) {
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| 70 | n -= 8 * sizeof(size_t);
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| 71 | p[1] = p[0];
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| 72 | p[0] = 0;
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| 73 | }
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| 74 | p[1] <<= n;
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| 75 | p[1] |= p[0] >> (sizeof(size_t) * 8 - n);
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| 76 | p[0] <<= n;
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| 77 | }
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| 78 |
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| 79 | static inline void shr(size_t p[2], int n)
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| 80 | {
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| 81 | if(n >= 8 * sizeof(size_t)) {
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| 82 | n -= 8 * sizeof(size_t);
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| 83 | p[0] = p[1];
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| 84 | p[1] = 0;
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| 85 | }
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| 86 | p[0] >>= n;
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| 87 | p[0] |= p[1] << (sizeof(size_t) * 8 - n);
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| 88 | p[1] >>= n;
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| 89 | }
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| 90 |
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| 91 | static void sift(unsigned char *head, size_t width, cmpfun cmp, int pshift, size_t lp[])
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| 92 | {
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| 93 | unsigned char *rt, *lf;
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| 94 | unsigned char *ar[14 * sizeof(size_t) + 1];
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| 95 | int i = 1;
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| 96 |
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| 97 | ar[0] = head;
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| 98 | while(pshift > 1) {
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| 99 | rt = head - width;
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| 100 | lf = head - width - lp[pshift - 2];
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| 101 |
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| 102 | if((*cmp)(ar[0], lf) >= 0 && (*cmp)(ar[0], rt) >= 0) {
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| 103 | break;
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| 104 | }
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| 105 | if((*cmp)(lf, rt) >= 0) {
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| 106 | ar[i++] = lf;
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| 107 | head = lf;
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| 108 | pshift -= 1;
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| 109 | } else {
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| 110 | ar[i++] = rt;
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| 111 | head = rt;
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| 112 | pshift -= 2;
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| 113 | }
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| 114 | }
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| 115 | cycle(width, ar, i);
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| 116 | }
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| 117 |
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| 118 | static void trinkle(unsigned char *head, size_t width, cmpfun cmp, size_t pp[2], int pshift, int trusty, size_t lp[])
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| 119 | {
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| 120 | unsigned char *stepson,
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| 121 | *rt, *lf;
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| 122 | size_t p[2];
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| 123 | unsigned char *ar[14 * sizeof(size_t) + 1];
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| 124 | int i = 1;
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| 125 | int trail;
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| 126 |
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| 127 | p[0] = pp[0];
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| 128 | p[1] = pp[1];
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| 129 |
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| 130 | ar[0] = head;
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| 131 | while(p[0] != 1 || p[1] != 0) {
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| 132 | stepson = head - lp[pshift];
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| 133 | if((*cmp)(stepson, ar[0]) <= 0) {
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| 134 | break;
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| 135 | }
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| 136 | if(!trusty && pshift > 1) {
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| 137 | rt = head - width;
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| 138 | lf = head - width - lp[pshift - 2];
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| 139 | if((*cmp)(rt, stepson) >= 0 || (*cmp)(lf, stepson) >= 0) {
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| 140 | break;
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| 141 | }
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| 142 | }
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| 143 |
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| 144 | ar[i++] = stepson;
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| 145 | head = stepson;
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| 146 | trail = pntz(p);
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| 147 | shr(p, trail);
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| 148 | pshift += trail;
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| 149 | trusty = 0;
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| 150 | }
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| 151 | if(!trusty) {
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| 152 | cycle(width, ar, i);
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| 153 | sift(head, width, cmp, pshift, lp);
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| 154 | }
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| 155 | }
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| 156 |
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| 157 | void qsort(void *base, size_t nel, size_t width, cmpfun cmp)
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| 158 | {
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| 159 | size_t lp[12*sizeof(size_t)];
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| 160 | size_t i, size = width * nel;
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| 161 | unsigned char *head, *high;
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| 162 | size_t p[2] = {1, 0};
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| 163 | int pshift = 1;
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| 164 | int trail;
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| 165 |
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| 166 | if (!size) return;
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| 167 |
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| 168 | head = base;
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| 169 | high = head + size - width;
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| 170 |
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| 171 | /* Precompute Leonardo numbers, scaled by element width */
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| 172 | for(lp[0]=lp[1]=width, i=2; (lp[i]=lp[i-2]+lp[i-1]+width) < size; i++);
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| 173 |
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| 174 | while(head < high) {
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| 175 | if((p[0] & 3) == 3) {
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| 176 | sift(head, width, cmp, pshift, lp);
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| 177 | shr(p, 2);
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| 178 | pshift += 2;
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| 179 | } else {
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| 180 | if(lp[pshift - 1] >= high - head) {
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| 181 | trinkle(head, width, cmp, p, pshift, 0, lp);
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| 182 | } else {
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| 183 | sift(head, width, cmp, pshift, lp);
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| 184 | }
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| 185 |
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| 186 | if(pshift == 1) {
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| 187 | shl(p, 1);
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| 188 | pshift = 0;
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| 189 | } else {
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| 190 | shl(p, pshift - 1);
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| 191 | pshift = 1;
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| 192 | }
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| 193 | }
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| 194 |
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| 195 | p[0] |= 1;
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| 196 | head += width;
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| 197 | }
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| 198 |
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| 199 | trinkle(head, width, cmp, p, pshift, 0, lp);
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| 200 |
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| 201 | while(pshift != 1 || p[0] != 1 || p[1] != 0) {
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| 202 | if(pshift <= 1) {
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| 203 | trail = pntz(p);
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| 204 | shr(p, trail);
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| 205 | pshift += trail;
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| 206 | } else {
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| 207 | shl(p, 2);
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| 208 | pshift -= 2;
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| 209 | p[0] ^= 7;
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| 210 | shr(p, 1);
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| 211 | trinkle(head - lp[pshift] - width, width, cmp, p, pshift + 1, 1, lp);
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| 212 | shl(p, 1);
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| 213 | p[0] |= 1;
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| 214 | trinkle(head - width, width, cmp, p, pshift, 1, lp);
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| 215 | }
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| 216 | head -= width;
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| 217 | }
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| 218 | }
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