1 /* 2 * Copyright © 2017 Google, Inc. 3 * 4 * This is part of HarfBuzz, a text shaping library. 5 * 6 * Permission is hereby granted, without written agreement and without 7 * license or royalty fees, to use, copy, modify, and distribute this 8 * software and its documentation for any purpose, provided that the 9 * above copyright notice and the following two paragraphs appear in 10 * all copies of this software. 11 * 12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR 13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN 15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 16 * DAMAGE. 17 * 18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, 19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO 22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 23 * 24 * Google Author(s): Behdad Esfahbod 25 */ 26 27 #ifndef HB_DSALGS_HH 28 #define HB_DSALGS_HH 29 30 #include "hb-private.hh" 31 32 33 static inline void * 34 hb_bsearch_r (const void *key, const void *base, 35 size_t nmemb, size_t size, 36 int (*compar)(const void *_key, const void *_item, void *_arg), 37 void *arg) 38 { 39 int min = 0, max = (int) nmemb - 1; 40 while (min <= max) 41 { 42 int mid = (min + max) / 2; 43 const void *p = (const void *) (((const char *) base) + (mid * size)); 44 int c = compar (key, p, arg); 45 if (c < 0) 46 max = mid - 1; 47 else if (c > 0) 48 min = mid + 1; 49 else 50 return (void *) p; 51 } 52 return NULL; 53 } 54 55 56 57 /* From https://github.com/noporpoise/sort_r */ 58 59 /* Isaac Turner 29 April 2014 Public Domain */ 60 61 /* 62 63 hb_sort_r function to be exported. 64 65 Parameters: 66 base is the array to be sorted 67 nel is the number of elements in the array 68 width is the size in bytes of each element of the array 69 compar is the comparison function 70 arg is a pointer to be passed to the comparison function 71 72 void hb_sort_r(void *base, size_t nel, size_t width, 73 int (*compar)(const void *_a, const void *_b, void *_arg), 74 void *arg); 75 */ 76 77 78 /* swap a, b iff a>b */ 79 #ifndef __SUNPRO_CC 80 /* __restrict is same as restrict but better support on old machines */ 81 static int sort_r_cmpswap(char *__restrict a, char *__restrict b, size_t w, 82 #else 83 static int sort_r_cmpswap(char *a, char *b, size_t w, 84 #endif 85 int (*compar)(const void *_a, const void *_b, 86 void *_arg), 87 void *arg) 88 { 89 char tmp, *end = a+w; 90 if(compar(a, b, arg) > 0) { 91 for(; a < end; a++, b++) { tmp = *a; *a = *b; *b = tmp; } 92 return 1; 93 } 94 return 0; 95 } 96 97 /* Note: quicksort is not stable, equivalent values may be swapped */ 98 static inline void sort_r_simple(void *base, size_t nel, size_t w, 99 int (*compar)(const void *_a, const void *_b, 100 void *_arg), 101 void *arg) 102 { 103 char *b = (char *)base, *end = b + nel*w; 104 if(nel < 7) { 105 /* Insertion sort for arbitrarily small inputs */ 106 char *pi, *pj; 107 for(pi = b+w; pi < end; pi += w) { 108 for(pj = pi; pj > b && sort_r_cmpswap(pj-w,pj,w,compar,arg); pj -= w) {} 109 } 110 } 111 else 112 { 113 /* nel > 6; Quicksort */ 114 115 /* Use median of first, middle and last items as pivot */ 116 char *x, *y, *xend, ch; 117 char *pl, *pr; 118 char *last = b+w*(nel-1), *tmp; 119 char *l[3]; 120 l[0] = b; 121 l[1] = b+w*(nel/2); 122 l[2] = last; 123 124 if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; } 125 if(compar(l[1],l[2],arg) > 0) { 126 tmp=l[1]; l[1]=l[2]; l[2]=tmp; /* swap(l[1],l[2]) */ 127 if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; } 128 } 129 130 /* swap l[id], l[2] to put pivot as last element */ 131 for(x = l[1], y = last, xend = x+w; x<xend; x++, y++) { 132 ch = *x; *x = *y; *y = ch; 133 } 134 135 pl = b; 136 pr = last; 137 138 while(pl < pr) { 139 for(; pl < pr; pl += w) { 140 if(sort_r_cmpswap(pl, pr, w, compar, arg)) { 141 pr -= w; /* pivot now at pl */ 142 break; 143 } 144 } 145 for(; pl < pr; pr -= w) { 146 if(sort_r_cmpswap(pl, pr, w, compar, arg)) { 147 pl += w; /* pivot now at pr */ 148 break; 149 } 150 } 151 } 152 153 sort_r_simple(b, (pl-b)/w, w, compar, arg); 154 sort_r_simple(pl+w, (end-(pl+w))/w, w, compar, arg); 155 } 156 } 157 158 static inline void hb_sort_r(void *base, size_t nel, size_t width, 159 int (*compar)(const void *_a, const void *_b, void *_arg), 160 void *arg) 161 { 162 sort_r_simple(base, nel, width, compar, arg); 163 } 164 165 #endif /* HB_DSALGS_HH */