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 /* __restrict is same as restrict but better support on old machines */ 80 static int sort_r_cmpswap(char *__restrict a, char *__restrict b, size_t w, 81 int (*compar)(const void *_a, const void *_b, 82 void *_arg), 83 void *arg) 84 { 85 char tmp, *end = a+w; 86 if(compar(a, b, arg) > 0) { 87 for(; a < end; a++, b++) { tmp = *a; *a = *b; *b = tmp; } 88 return 1; 89 } 90 return 0; 91 } 92 93 /* Note: quicksort is not stable, equivalent values may be swapped */ 94 static inline void sort_r_simple(void *base, size_t nel, size_t w, 95 int (*compar)(const void *_a, const void *_b, 96 void *_arg), 97 void *arg) 98 { 99 char *b = (char *)base, *end = b + nel*w; 100 if(nel < 7) { 101 /* Insertion sort for arbitrarily small inputs */ 102 char *pi, *pj; 103 for(pi = b+w; pi < end; pi += w) { 104 for(pj = pi; pj > b && sort_r_cmpswap(pj-w,pj,w,compar,arg); pj -= w) {} 105 } 106 } 107 else 108 { 109 /* nel > 6; Quicksort */ 110 111 /* Use median of first, middle and last items as pivot */ 112 char *x, *y, *xend, ch; 113 char *pl, *pr; 114 char *last = b+w*(nel-1), *tmp; 115 char *l[3]; 116 l[0] = b; 117 l[1] = b+w*(nel/2); 118 l[2] = last; 119 120 if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; } 121 if(compar(l[1],l[2],arg) > 0) { 122 tmp=l[1]; l[1]=l[2]; l[2]=tmp; /* swap(l[1],l[2]) */ 123 if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; } 124 } 125 126 /* swap l[id], l[2] to put pivot as last element */ 127 for(x = l[1], y = last, xend = x+w; x<xend; x++, y++) { 128 ch = *x; *x = *y; *y = ch; 129 } 130 131 pl = b; 132 pr = last; 133 134 while(pl < pr) { 135 for(; pl < pr; pl += w) { 136 if(sort_r_cmpswap(pl, pr, w, compar, arg)) { 137 pr -= w; /* pivot now at pl */ 138 break; 139 } 140 } 141 for(; pl < pr; pr -= w) { 142 if(sort_r_cmpswap(pl, pr, w, compar, arg)) { 143 pl += w; /* pivot now at pr */ 144 break; 145 } 146 } 147 } 148 149 sort_r_simple(b, (pl-b)/w, w, compar, arg); 150 sort_r_simple(pl+w, (end-(pl+w))/w, w, compar, arg); 151 } 152 } 153 154 static inline void hb_sort_r(void *base, size_t nel, size_t width, 155 int (*compar)(const void *_a, const void *_b, void *_arg), 156 void *arg) 157 { 158 sort_r_simple(base, nel, width, compar, arg); 159 } 160 161 #endif /* HB_DSALGS_HH */ 162
