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 #if defined(__ghs)
33 // GHS compiler doesn't support the __restrict keyword
34 #define __restrict
35 #endif
36
37
38
39 static inline void *
hb_bsearch_r(const void * key,const void * base,size_t nmemb,size_t size,int (* compar)(const void * _key,const void * _item,void * _arg),void * arg)40 hb_bsearch_r (const void *key, const void *base,
41 size_t nmemb, size_t size,
42 int (*compar)(const void *_key, const void *_item, void *_arg),
43 void *arg)
44 {
45 int min = 0, max = (int) nmemb - 1;
46 while (min <= max)
47 {
48 int mid = (min + max) / 2;
49 const void *p = (const void *) (((const char *) base) + (mid * size));
50 int c = compar (key, p, arg);
51 if (c < 0)
52 max = mid - 1;
53 else if (c > 0)
54 min = mid + 1;
55 else
56 return (void *) p;
57 }
58 return NULL;
59 }
60
61
62
63 /* From https://github.com/noporpoise/sort_r */
64
65 /* Isaac Turner 29 April 2014 Public Domain */
66
67 /*
68
69 hb_sort_r function to be exported.
70
71 Parameters:
72 base is the array to be sorted
73 nel is the number of elements in the array
74 width is the size in bytes of each element of the array
75 compar is the comparison function
76 arg is a pointer to be passed to the comparison function
77
78 void hb_sort_r(void *base, size_t nel, size_t width,
79 int (*compar)(const void *_a, const void *_b, void *_arg),
80 void *arg);
81 */
82
83
84 /* swap a, b iff a>b */
85 /* __restrict is same as restrict but better support on old machines */
sort_r_cmpswap(char * __restrict a,char * __restrict b,size_t w,int (* compar)(const void * _a,const void * _b,void * _arg),void * arg)86 static int sort_r_cmpswap(char *__restrict a, char *__restrict b, size_t w,
87 int (*compar)(const void *_a, const void *_b,
88 void *_arg),
89 void *arg)
90 {
91 char tmp, *end = a+w;
92 if(compar(a, b, arg) > 0) {
93 for(; a < end; a++, b++) { tmp = *a; *a = *b; *b = tmp; }
94 return 1;
95 }
96 return 0;
97 }
98
99 /* Note: quicksort is not stable, equivalent values may be swapped */
sort_r_simple(void * base,size_t nel,size_t w,int (* compar)(const void * _a,const void * _b,void * _arg),void * arg)100 static inline void sort_r_simple(void *base, size_t nel, size_t w,
101 int (*compar)(const void *_a, const void *_b,
102 void *_arg),
103 void *arg)
104 {
105 char *b = (char *)base, *end = b + nel*w;
106 if(nel < 7) {
107 /* Insertion sort for arbitrarily small inputs */
108 char *pi, *pj;
109 for(pi = b+w; pi < end; pi += w) {
110 for(pj = pi; pj > b && sort_r_cmpswap(pj-w,pj,w,compar,arg); pj -= w) {}
111 }
112 }
113 else
114 {
115 /* nel > 6; Quicksort */
116
117 /* Use median of first, middle and last items as pivot */
118 char *x, *y, *xend, ch;
119 char *pl, *pr;
120 char *last = b+w*(nel-1), *tmp;
121 char *l[3];
122 l[0] = b;
123 l[1] = b+w*(nel/2);
124 l[2] = last;
125
126 if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; }
127 if(compar(l[1],l[2],arg) > 0) {
128 tmp=l[1]; l[1]=l[2]; l[2]=tmp; /* swap(l[1],l[2]) */
129 if(compar(l[0],l[1],arg) > 0) { tmp=l[0]; l[0]=l[1]; l[1]=tmp; }
130 }
131
132 /* swap l[id], l[2] to put pivot as last element */
133 for(x = l[1], y = last, xend = x+w; x<xend; x++, y++) {
134 ch = *x; *x = *y; *y = ch;
135 }
136
137 pl = b;
138 pr = last;
139
140 while(pl < pr) {
141 for(; pl < pr; pl += w) {
142 if(sort_r_cmpswap(pl, pr, w, compar, arg)) {
143 pr -= w; /* pivot now at pl */
144 break;
145 }
146 }
147 for(; pl < pr; pr -= w) {
148 if(sort_r_cmpswap(pl, pr, w, compar, arg)) {
149 pl += w; /* pivot now at pr */
150 break;
151 }
152 }
153 }
154
155 sort_r_simple(b, (pl-b)/w, w, compar, arg);
156 sort_r_simple(pl+w, (end-(pl+w))/w, w, compar, arg);
157 }
158 }
159
hb_sort_r(void * base,size_t nel,size_t width,int (* compar)(const void * _a,const void * _b,void * _arg),void * arg)160 static inline void hb_sort_r(void *base, size_t nel, size_t width,
161 int (*compar)(const void *_a, const void *_b, void *_arg),
162 void *arg)
163 {
164 sort_r_simple(base, nel, width, compar, arg);
165 }
166
167 #endif /* HB_DSALGS_HH */
168