|
1 | 1 | /* |
2 | 2 | *qsort.c: standard quicksort algorithm |
3 | | - * |
4 | | - *Modifications from vanilla NetBSD source: |
5 | | - * Add do ... while() macro fix |
6 | | - * Remove __inline, _DIAGASSERTs, __P |
7 | | - * Remove ill-considered "swap_cnt" switch to insertion sort, |
8 | | - * in favor of a simple check for presorted input. |
9 | | - * Take care to recurse on the smaller partition, to bound stack usage. |
10 | | - * |
11 | | - *CAUTION: if you change this file, see also qsort_arg.c, gen_qsort_tuple.pl |
12 | | - * |
13 | | - *src/port/qsort.c |
14 | | - */ |
15 | | - |
16 | | -/*$NetBSD: qsort.c,v 1.13 2003/08/07 16:43:42 agc Exp $*/ |
17 | | - |
18 | | -/*- |
19 | | - * Copyright (c) 1992, 1993 |
20 | | - *The Regents of the University of California. All rights reserved. |
21 | | - * |
22 | | - * Redistribution and use in source and binary forms, with or without |
23 | | - * modification, are permitted provided that the following conditions |
24 | | - * are met: |
25 | | - * 1. Redistributions of source code must retain the above copyright |
26 | | - * notice, this list of conditions and the following disclaimer. |
27 | | - * 2. Redistributions in binary form must reproduce the above copyright |
28 | | - * notice, this list of conditions and the following disclaimer in the |
29 | | - * documentation and/or other materials provided with the distribution. |
30 | | - * 3. Neither the name of the University nor the names of its contributors |
31 | | - * may be used to endorse or promote products derived from this software |
32 | | - * without specific prior written permission. |
33 | | - * |
34 | | - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
35 | | - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
36 | | - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
37 | | - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
38 | | - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
39 | | - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
40 | | - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
41 | | - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
42 | | - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
43 | | - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
44 | | - * SUCH DAMAGE. |
45 | 3 | */ |
46 | 4 |
|
47 | 5 | #include"c.h" |
48 | 6 |
|
49 | | - |
50 | | -staticchar*med3(char*a,char*b,char*c, |
51 | | -int (*cmp) (constvoid*,constvoid*)); |
52 | | -staticvoidswapfunc(char*,char*,size_t,int); |
53 | | - |
54 | | -/* |
55 | | - * Qsort routine based on J. L. Bentley and M. D. McIlroy, |
56 | | - * "Engineering a sort function", |
57 | | - * Software--Practice and Experience 23 (1993) 1249-1265. |
58 | | - * |
59 | | - * We have modified their original by adding a check for already-sorted input, |
60 | | - * which seems to be a win per discussions on pgsql-hackers around 2006-03-21. |
61 | | - * |
62 | | - * Also, we recurse on the smaller partition and iterate on the larger one, |
63 | | - * which ensures we cannot recurse more than log(N) levels (since the |
64 | | - * partition recursed to is surely no more than half of the input). Bentley |
65 | | - * and McIlroy explicitly rejected doing this on the grounds that it's "not |
66 | | - * worth the effort", but we have seen crashes in the field due to stack |
67 | | - * overrun, so that judgment seems wrong. |
68 | | - */ |
69 | | - |
70 | | -#defineswapcode(TYPE,parmi,parmj,n) \ |
71 | | -do {\ |
72 | | -size_t i = (n) / sizeof (TYPE);\ |
73 | | -TYPE *pi = (TYPE *)(void *)(parmi);\ |
74 | | -TYPE *pj = (TYPE *)(void *)(parmj);\ |
75 | | -do {\ |
76 | | -TYPEt = *pi;\ |
77 | | -*pi++ = *pj;\ |
78 | | -*pj++ = t;\ |
79 | | -} while (--i > 0);\ |
80 | | -} while (0) |
81 | | - |
82 | | -#defineSWAPINIT(a,es) swaptype = ((char *)(a) - (char *)0) % sizeof(long) || \ |
83 | | -(es) % sizeof(long) ? 2 : (es) == sizeof(long)? 0 : 1 |
84 | | - |
85 | | -staticvoid |
86 | | -swapfunc(char*a,char*b,size_tn,intswaptype) |
87 | | -{ |
88 | | -if (swaptype <=1) |
89 | | -swapcode(long,a,b,n); |
90 | | -else |
91 | | -swapcode(char,a,b,n); |
92 | | -} |
93 | | - |
94 | | -#defineswap(a,b)\ |
95 | | -if (swaptype == 0) {\ |
96 | | -long t = *(long *)(void *)(a);\ |
97 | | -*(long *)(void *)(a) = *(long *)(void *)(b);\ |
98 | | -*(long *)(void *)(b) = t;\ |
99 | | -} else\ |
100 | | -swapfunc(a, b, es, swaptype) |
101 | | - |
102 | | -#definevecswap(a,b,n) if ((n) > 0) swapfunc(a, b, n, swaptype) |
103 | | - |
104 | | -staticchar* |
105 | | -med3(char*a,char*b,char*c,int (*cmp) (constvoid*,constvoid*)) |
106 | | -{ |
107 | | -returncmp(a,b)<0 ? |
108 | | -(cmp(b,c)<0 ?b : (cmp(a,c)<0 ?c :a)) |
109 | | -: (cmp(b,c)>0 ?b : (cmp(a,c)<0 ?a :c)); |
110 | | -} |
111 | | - |
112 | | -void |
113 | | -pg_qsort(void*a,size_tn,size_tes,int (*cmp) (constvoid*,constvoid*)) |
114 | | -{ |
115 | | -char*pa, |
116 | | -*pb, |
117 | | -*pc, |
118 | | -*pd, |
119 | | -*pl, |
120 | | -*pm, |
121 | | -*pn; |
122 | | -size_td1, |
123 | | -d2; |
124 | | -intr, |
125 | | -swaptype, |
126 | | -presorted; |
127 | | - |
128 | | -loop:SWAPINIT(a,es); |
129 | | -if (n<7) |
130 | | -{ |
131 | | -for (pm= (char*)a+es;pm< (char*)a+n*es;pm+=es) |
132 | | -for (pl=pm;pl> (char*)a&&cmp(pl-es,pl)>0; |
133 | | -pl-=es) |
134 | | -swap(pl,pl-es); |
135 | | -return; |
136 | | -} |
137 | | -presorted=1; |
138 | | -for (pm= (char*)a+es;pm< (char*)a+n*es;pm+=es) |
139 | | -{ |
140 | | -if (cmp(pm-es,pm)>0) |
141 | | -{ |
142 | | -presorted=0; |
143 | | -break; |
144 | | -} |
145 | | -} |
146 | | -if (presorted) |
147 | | -return; |
148 | | -pm= (char*)a+ (n /2)*es; |
149 | | -if (n>7) |
150 | | -{ |
151 | | -pl= (char*)a; |
152 | | -pn= (char*)a+ (n-1)*es; |
153 | | -if (n>40) |
154 | | -{ |
155 | | -size_td= (n /8)*es; |
156 | | - |
157 | | -pl=med3(pl,pl+d,pl+2*d,cmp); |
158 | | -pm=med3(pm-d,pm,pm+d,cmp); |
159 | | -pn=med3(pn-2*d,pn-d,pn,cmp); |
160 | | -} |
161 | | -pm=med3(pl,pm,pn,cmp); |
162 | | -} |
163 | | -swap(a,pm); |
164 | | -pa=pb= (char*)a+es; |
165 | | -pc=pd= (char*)a+ (n-1)*es; |
166 | | -for (;;) |
167 | | -{ |
168 | | -while (pb <=pc&& (r=cmp(pb,a)) <=0) |
169 | | -{ |
170 | | -if (r==0) |
171 | | -{ |
172 | | -swap(pa,pb); |
173 | | -pa+=es; |
174 | | -} |
175 | | -pb+=es; |
176 | | -} |
177 | | -while (pb <=pc&& (r=cmp(pc,a)) >=0) |
178 | | -{ |
179 | | -if (r==0) |
180 | | -{ |
181 | | -swap(pc,pd); |
182 | | -pd-=es; |
183 | | -} |
184 | | -pc-=es; |
185 | | -} |
186 | | -if (pb>pc) |
187 | | -break; |
188 | | -swap(pb,pc); |
189 | | -pb+=es; |
190 | | -pc-=es; |
191 | | -} |
192 | | -pn= (char*)a+n*es; |
193 | | -d1=Min(pa- (char*)a,pb-pa); |
194 | | -vecswap(a,pb-d1,d1); |
195 | | -d1=Min(pd-pc,pn-pd-es); |
196 | | -vecswap(pb,pn-d1,d1); |
197 | | -d1=pb-pa; |
198 | | -d2=pd-pc; |
199 | | -if (d1 <=d2) |
200 | | -{ |
201 | | -/* Recurse on left partition, then iterate on right partition */ |
202 | | -if (d1>es) |
203 | | -pg_qsort(a,d1 /es,es,cmp); |
204 | | -if (d2>es) |
205 | | -{ |
206 | | -/* Iterate rather than recurse to save stack space */ |
207 | | -/* pg_qsort(pn - d2, d2 / es, es, cmp); */ |
208 | | -a=pn-d2; |
209 | | -n=d2 /es; |
210 | | -gotoloop; |
211 | | -} |
212 | | -} |
213 | | -else |
214 | | -{ |
215 | | -/* Recurse on right partition, then iterate on left partition */ |
216 | | -if (d2>es) |
217 | | -pg_qsort(pn-d2,d2 /es,es,cmp); |
218 | | -if (d1>es) |
219 | | -{ |
220 | | -/* Iterate rather than recurse to save stack space */ |
221 | | -/* pg_qsort(a, d1 / es, es, cmp); */ |
222 | | -n=d1 /es; |
223 | | -gotoloop; |
224 | | -} |
225 | | -} |
226 | | -} |
| 7 | +#defineST_SORT pg_qsort |
| 8 | +#defineST_ELEMENT_TYPE_VOID |
| 9 | +#defineST_COMPARE_RUNTIME_POINTER |
| 10 | +#defineST_SCOPE |
| 11 | +#defineST_DECLARE |
| 12 | +#defineST_DEFINE |
| 13 | +#include"lib/sort_template.h" |
227 | 14 |
|
228 | 15 | /* |
229 | 16 | * qsort comparator wrapper for strcmp. |
|