Mercurial > hg > xemacs-beta
annotate lib-src/qsort.c @ 5887:6eca500211f4
Prototype for X509_check_host() has changed, detect this in configure.ac
ChangeLog addition:
2015-04-09 Aidan Kehoe <kehoea@parhasard.net>
* configure.ac:
If X509_check_host() is available, check the number of arguments
it takes. Don't use it if it takes any number of arguments other
than five. Also don't use it if <openssl/x509v3.h> does not
declare it, since if that is so there is no portable way to tell
how many arguments it should take, and so we would end up smashing
the stack.
* configure: Regenerate.
src/ChangeLog addition:
2015-04-09 Aidan Kehoe <kehoea@parhasard.net>
* tls.c:
#include <openssl/x509v3.h> for its prototype for
X509_check_host().
* tls.c (tls_open):
Pass the new fifth argument to X509_check_host().
| author | Aidan Kehoe <kehoea@parhasard.net> |
|---|---|
| date | Thu, 09 Apr 2015 14:27:02 +0100 |
| parents | 061f4f90f874 |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* Plug-compatible replacement for UNIX qsort. |
| 2 Copyright (C) 1989 Free Software Foundation, Inc. | |
| 3 Written by Douglas C. Schmidt (schmidt@ics.uci.edu) | |
| 4 | |
| 5 This file is part of GNU CC. | |
| 6 | |
|
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7 GNU QSORT is free software: you can redistribute it and/or modify it |
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8 under the terms of the GNU General Public License as published by the |
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9 Free Software Foundation, either version 3 of the License, or (at your |
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10 option) any later version. |
| 0 | 11 |
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12 GNU QSORT is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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15 for more details. |
| 0 | 16 |
| 17 You should have received a copy of the GNU General Public License | |
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18 along with GNU QSORT. If not, see <http://www.gnu.org/licenses/>. */ |
| 0 | 19 |
| 20 /* Synched up with: FSF 19.28. */ | |
| 21 | |
| 22 #ifdef sparc | |
| 23 #include <alloca.h> | |
| 24 #endif | |
| 25 | |
| 26 /* Invoke the comparison function, returns either 0, < 0, or > 0. */ | |
| 27 #define CMP(A,B) ((*cmp)((A),(B))) | |
| 28 | |
| 29 /* Byte-wise swap two items of size SIZE. */ | |
| 30 #define SWAP(A,B,SIZE) do {int sz = (SIZE); char *a = (A); char *b = (B); \ | |
| 31 do { char _temp = *a;*a++ = *b;*b++ = _temp;} while (--sz);} while (0) | |
| 32 | |
| 33 /* Copy SIZE bytes from item B to item A. */ | |
| 34 #define COPY(A,B,SIZE) {int sz = (SIZE); do { *(A)++ = *(B)++; } while (--sz); } | |
| 35 | |
| 36 /* This should be replaced by a standard ANSI macro. */ | |
| 37 #define BYTES_PER_WORD 8 | |
| 38 | |
| 39 /* The next 4 #defines implement a very fast in-line stack abstraction. */ | |
| 40 #define STACK_SIZE (BYTES_PER_WORD * sizeof (long)) | |
| 41 #define PUSH(LOW,HIGH) do {top->lo = LOW;top++->hi = HIGH;} while (0) | |
| 42 #define POP(LOW,HIGH) do {LOW = (--top)->lo;HIGH = top->hi;} while (0) | |
| 43 #define STACK_NOT_EMPTY (stack < top) | |
| 44 | |
| 45 /* Discontinue quicksort algorithm when partition gets below this size. | |
| 46 This particular magic number was chosen to work best on a Sun 4/260. */ | |
| 47 #define MAX_THRESH 4 | |
| 48 | |
| 49 /* Stack node declarations used to store unfulfilled partition obligations. */ | |
| 50 typedef struct | |
| 51 { | |
| 52 char *lo; | |
| 53 char *hi; | |
| 54 } stack_node; | |
| 55 | |
| 56 /* Order size using quicksort. This implementation incorporates | |
| 57 four optimizations discussed in Sedgewick: | |
| 58 | |
| 59 1. Non-recursive, using an explicit stack of pointer that store the | |
| 60 next array partition to sort. To save time, this maximum amount | |
| 61 of space required to store an array of MAX_INT is allocated on the | |
| 62 stack. Assuming a 32-bit integer, this needs only 32 * | |
| 63 sizeof (stack_node) == 136 bits. Pretty cheap, actually. | |
| 64 | |
| 444 | 65 2. Choose the pivot element using a median-of-three decision tree. |
| 0 | 66 This reduces the probability of selecting a bad pivot value and |
| 67 eliminates certain extraneous comparisons. | |
| 68 | |
| 69 3. Only quicksorts TOTAL_ELEMS / MAX_THRESH partitions, leaving | |
| 70 insertion sort to order the MAX_THRESH items within each partition. | |
| 71 This is a big win, since insertion sort is faster for small, mostly | |
| 72 sorted array segments. | |
| 73 | |
| 74 4. The larger of the two sub-partitions is always pushed onto the | |
| 75 stack first, with the algorithm then concentrating on the | |
| 76 smaller partition. This *guarantees* no more than log (n) | |
| 77 stack size is needed (actually O(1) in this case)! */ | |
| 78 | |
| 79 int | |
| 80 qsort (base_ptr, total_elems, size, cmp) | |
| 81 char *base_ptr; | |
| 82 int total_elems; | |
| 83 int size; | |
| 84 int (*cmp)(); | |
| 85 { | |
| 86 /* Allocating SIZE bytes for a pivot buffer facilitates a better | |
| 87 algorithm below since we can do comparisons directly on the pivot. */ | |
| 88 char *pivot_buffer = (char *) alloca (size); | |
| 89 int max_thresh = MAX_THRESH * size; | |
| 90 | |
| 91 if (total_elems > MAX_THRESH) | |
| 92 { | |
| 93 char *lo = base_ptr; | |
| 94 char *hi = lo + size * (total_elems - 1); | |
| 95 stack_node stack[STACK_SIZE]; /* Largest size needed for 32-bit int!!! */ | |
| 96 stack_node *top = stack + 1; | |
| 97 | |
| 98 while (STACK_NOT_EMPTY) | |
| 99 { | |
| 100 char *left_ptr; | |
| 101 char *right_ptr; | |
| 102 { | |
| 103 char *pivot = pivot_buffer; | |
| 104 { | |
| 105 /* Select median value from among LO, MID, and HI. Rearrange | |
| 106 LO and HI so the three values are sorted. This lowers the | |
| 107 probability of picking a pathological pivot value and | |
| 108 skips a comparison for both the LEFT_PTR and RIGHT_PTR. */ | |
| 109 | |
| 110 char *mid = lo + size * ((hi - lo) / size >> 1); | |
| 111 | |
| 112 if (CMP (mid, lo) < 0) | |
| 113 SWAP (mid, lo, size); | |
| 114 if (CMP (hi, mid) < 0) | |
| 115 SWAP (mid, hi, size); | |
| 116 else | |
| 117 goto jump_over; | |
| 118 if (CMP (mid, lo) < 0) | |
| 119 SWAP (mid, lo, size); | |
| 120 jump_over: | |
| 121 COPY (pivot, mid, size); | |
| 122 pivot = pivot_buffer; | |
| 123 } | |
| 124 left_ptr = lo + size; | |
| 125 right_ptr = hi - size; | |
| 126 | |
| 127 /* Here's the famous ``collapse the walls'' section of quicksort. | |
| 128 Gotta like those tight inner loops! They are the main reason | |
| 129 that this algorithm runs much faster than others. */ | |
| 130 do | |
| 131 { | |
| 132 while (CMP (left_ptr, pivot) < 0) | |
| 133 left_ptr += size; | |
| 134 | |
| 135 while (CMP (pivot, right_ptr) < 0) | |
| 136 right_ptr -= size; | |
| 137 | |
| 138 if (left_ptr < right_ptr) | |
| 139 { | |
| 140 SWAP (left_ptr, right_ptr, size); | |
| 141 left_ptr += size; | |
| 142 right_ptr -= size; | |
| 143 } | |
| 144 else if (left_ptr == right_ptr) | |
| 145 { | |
| 146 left_ptr += size; | |
| 147 right_ptr -= size; | |
| 148 break; | |
| 149 } | |
| 150 } | |
| 151 while (left_ptr <= right_ptr); | |
| 152 | |
| 153 } | |
| 154 | |
| 155 /* Set up pointers for next iteration. First determine whether | |
| 156 left and right partitions are below the threshold size. If so, | |
| 157 ignore one or both. Otherwise, push the larger partition's | |
| 158 bounds on the stack and continue sorting the smaller one. */ | |
| 159 | |
| 160 if ((right_ptr - lo) <= max_thresh) | |
| 161 { | |
| 162 if ((hi - left_ptr) <= max_thresh) /* Ignore both small partitions. */ | |
| 163 POP (lo, hi); | |
| 164 else /* Ignore small left partition. */ | |
| 165 lo = left_ptr; | |
| 166 } | |
| 167 else if ((hi - left_ptr) <= max_thresh) /* Ignore small right partition. */ | |
| 168 hi = right_ptr; | |
| 169 else if ((right_ptr - lo) > (hi - left_ptr)) /* Push larger left partition indices. */ | |
| 170 { | |
| 171 PUSH (lo, right_ptr); | |
| 172 lo = left_ptr; | |
| 173 } | |
| 174 else /* Push larger right partition indices. */ | |
| 175 { | |
| 176 PUSH (left_ptr, hi); | |
| 177 hi = right_ptr; | |
| 178 } | |
| 179 } | |
| 180 } | |
| 181 | |
| 182 /* Once the BASE_PTR array is partially sorted by quicksort the rest | |
| 183 is completely sorted using insertion sort, since this is efficient | |
| 184 for partitions below MAX_THRESH size. BASE_PTR points to the beginning | |
| 185 of the array to sort, and END_PTR points at the very last element in | |
| 186 the array (*not* one beyond it!). */ | |
| 187 | |
| 188 #define MIN(X,Y) ((X) < (Y) ? (X) : (Y)) | |
| 189 | |
| 190 { | |
| 191 char *end_ptr = base_ptr + size * (total_elems - 1); | |
| 192 char *run_ptr; | |
| 193 char *tmp_ptr = base_ptr; | |
| 194 char *thresh = MIN (end_ptr, base_ptr + max_thresh); | |
| 195 | |
| 196 /* Find smallest element in first threshold and place it at the | |
| 197 array's beginning. This is the smallest array element, | |
| 198 and the operation speeds up insertion sort's inner loop. */ | |
| 199 | |
| 200 for (run_ptr = tmp_ptr + size; run_ptr <= thresh; run_ptr += size) | |
| 201 if (CMP (run_ptr, tmp_ptr) < 0) | |
| 202 tmp_ptr = run_ptr; | |
| 203 | |
| 204 if (tmp_ptr != base_ptr) | |
| 205 SWAP (tmp_ptr, base_ptr, size); | |
| 206 | |
| 207 /* Insertion sort, running from left-hand-side up to `right-hand-side.' | |
| 208 Pretty much straight out of the original GNU qsort routine. */ | |
| 209 | |
| 210 for (run_ptr = base_ptr + size; (tmp_ptr = run_ptr += size) <= end_ptr; ) | |
| 211 { | |
| 212 | |
| 213 while (CMP (run_ptr, tmp_ptr -= size) < 0) | |
| 214 ; | |
| 215 | |
| 216 if ((tmp_ptr += size) != run_ptr) | |
| 217 { | |
| 218 char *trav; | |
| 219 | |
| 220 for (trav = run_ptr + size; --trav >= run_ptr;) | |
| 221 { | |
| 222 char c = *trav; | |
| 223 char *hi, *lo; | |
| 224 | |
| 225 for (hi = lo = trav; (lo -= size) >= tmp_ptr; hi = lo) | |
| 226 *hi = *lo; | |
| 227 *hi = c; | |
| 228 } | |
| 229 } | |
| 230 | |
| 231 } | |
| 232 } | |
| 233 return 1; | |
| 234 } | |
| 235 |