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LCOV - code coverage report
Current view: top level - main - mergesort.c (source / functions) Hit Total Coverage
Test: PHP Code Coverage Lines: 0 137 0.0 %
Date: 2014-11-22 Functions: 0 3 0.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-
       2             :  * Copyright (c) 1992, 1993
       3             :  *      The Regents of the University of California.  All rights reserved.
       4             :  *
       5             :  * This code is derived from software contributed to Berkeley by
       6             :  * Peter McIlroy.
       7             :  *
       8             :  * Redistribution and use in source and binary forms, with or without
       9             :  * modification, are permitted provided that the following conditions
      10             :  * are met:
      11             :  * 1. Redistributions of source code must retain the above copyright
      12             :  *    notice, this list of conditions and the following disclaimer.
      13             :  * 2. Redistributions in binary form must reproduce the above copyright
      14             :  *    notice, this list of conditions and the following disclaimer in the
      15             :  *    documentation and/or other materials provided with the distribution.
      16             :  * 3. All advertising materials mentioning features or use of this software
      17             :  *    must display the following acknowledgement:
      18             :  *      This product includes software developed by the University of
      19             :  *      California, Berkeley and its contributors.
      20             :  * 4. Neither the name of the University nor the names of its contributors
      21             :  *    may be used to endorse or promote products derived from this software
      22             :  *    without specific prior written permission.
      23             :  *
      24             :  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
      25             :  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      26             :  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      27             :  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
      28             :  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
      29             :  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
      30             :  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
      31             :  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
      32             :  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
      33             :  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
      34             :  * SUCH DAMAGE.
      35             :  */
      36             : 
      37             : /* $Id$ */
      38             : 
      39             : #if defined(LIBC_SCCS) && !defined(lint)
      40             : static char sccsid[] = "@(#)merge.c        8.2 (Berkeley) 2/14/94";
      41             : #endif /* LIBC_SCCS and not lint */
      42             : 
      43             : /*
      44             :  * Hybrid exponential search/linear search merge sort with hybrid
      45             :  * natural/pairwise first pass.  Requires about .3% more comparisons
      46             :  * for random data than LSMS with pairwise first pass alone.
      47             :  * It works for objects as small as two bytes.
      48             :  */
      49             : 
      50             : #define NATURAL
      51             : #define THRESHOLD 16    /* Best choice for natural merge cut-off. */
      52             : 
      53             : /* #define NATURAL to get hybrid natural merge.
      54             :  * (The default is pairwise merging.)
      55             :  */
      56             : 
      57             : #include <sys/types.h>
      58             : 
      59             : #include <errno.h>
      60             : #include <stdlib.h>
      61             : #include <string.h>
      62             : 
      63             : #include "php.h"
      64             : 
      65             : #ifdef PHP_WIN32
      66             : #include <winsock2.h> /* Includes definition for u_char */
      67             : #endif
      68             : 
      69             : static void setup(u_char *list1, u_char *list2, size_t n, size_t size, int (*cmp)(const void *, const void * TSRMLS_DC) TSRMLS_DC);
      70             : static void insertionsort(u_char *a, size_t n, size_t size, int (*cmp)(const void *, const void * TSRMLS_DC) TSRMLS_DC);
      71             : 
      72             : #define ISIZE sizeof(int)
      73             : #define PSIZE sizeof(u_char *)
      74             : #define ICOPY_LIST(src, dst, last)                              \
      75             :         do                                                      \
      76             :         *(int*)dst = *(int*)src, src += ISIZE, dst += ISIZE;    \
      77             :         while(src < last)
      78             : #define ICOPY_ELT(src, dst, i)                                  \
      79             :         do                                                      \
      80             :         *(int*) dst = *(int*) src, src += ISIZE, dst += ISIZE;  \
      81             :         while (i -= ISIZE)
      82             : 
      83             : #define CCOPY_LIST(src, dst, last)              \
      84             :         do                                      \
      85             :                 *dst++ = *src++;                \
      86             :         while (src < last)
      87             : #define CCOPY_ELT(src, dst, i)                  \
      88             :         do                                      \
      89             :                 *dst++ = *src++;                \
      90             :         while (i -= 1)
      91             : 
      92             : /*
      93             :  * Find the next possible pointer head.  (Trickery for forcing an array
      94             :  * to do double duty as a linked list when objects do not align with word
      95             :  * boundaries.
      96             :  */
      97             : /* Assumption: PSIZE is a power of 2. */
      98             : #define EVAL(p) (u_char **)                                             \
      99             :         ((u_char *)0 +                                                  \
     100             :             (((u_char *)p + PSIZE - 1 - (u_char *) 0) & ~(PSIZE - 1)))
     101             : 
     102             : /* {{{ php_mergesort
     103             :  * Arguments are as for qsort.
     104             :  */
     105           0 : PHPAPI int php_mergesort(void *base, size_t nmemb, size_t size, int (*cmp)(const void *, const void * TSRMLS_DC) TSRMLS_DC)
     106             : {
     107             :         register size_t i;
     108             :         register int sense;
     109             :         int big, iflag;
     110             :         register u_char *f1, *f2, *t, *b, *tp2, *q, *l1, *l2;
     111             :         u_char *list2, *list1, *p2, *p, *last, **p1;
     112             : 
     113           0 :         if (size < PSIZE / 2) {              /* Pointers must fit into 2 * size. */
     114           0 :                 errno = EINVAL;
     115           0 :                 return (-1);
     116             :         }
     117             : 
     118           0 :         if (nmemb == 0)
     119           0 :                 return (0);
     120             : 
     121             :         /*
     122             :          * XXX
     123             :          * Stupid subtraction for the Cray.
     124             :          */
     125           0 :         iflag = 0;
     126           0 :         if (!(size % ISIZE) && !(((char *)base - (char *)0) % ISIZE))
     127           0 :                 iflag = 1;
     128             : 
     129           0 :         if ((list2 = malloc(nmemb * size + PSIZE)) == NULL)
     130           0 :                 return (-1);
     131             : 
     132           0 :         list1 = base;
     133           0 :         setup(list1, list2, nmemb, size, cmp TSRMLS_CC);
     134           0 :         last = list2 + nmemb * size;
     135           0 :         i = big = 0;
     136           0 :         while (*EVAL(list2) != last) {
     137           0 :             l2 = list1;
     138           0 :             p1 = EVAL(list1);
     139           0 :             for (tp2 = p2 = list2; p2 != last; p1 = EVAL(l2)) {
     140           0 :                 p2 = *EVAL(p2);
     141           0 :                 f1 = l2;
     142           0 :                 f2 = l1 = list1 + (p2 - list2);
     143           0 :                 if (p2 != last)
     144           0 :                         p2 = *EVAL(p2);
     145           0 :                 l2 = list1 + (p2 - list2);
     146           0 :                 while (f1 < l1 && f2 < l2) {
     147           0 :                         if ((*cmp)(f1, f2 TSRMLS_CC) <= 0) {
     148           0 :                                 q = f2;
     149           0 :                                 b = f1, t = l1;
     150           0 :                                 sense = -1;
     151             :                         } else {
     152           0 :                                 q = f1;
     153           0 :                                 b = f2, t = l2;
     154           0 :                                 sense = 0;
     155             :                         }
     156           0 :                         if (!big) {     /* here i = 0 */
     157           0 :                                 while ((b += size) < t && cmp(q, b TSRMLS_CC) >sense)
     158           0 :                                         if (++i == 6) {
     159           0 :                                                 big = 1;
     160           0 :                                                 goto EXPONENTIAL;
     161             :                                         }
     162             :                         } else {
     163           0 : EXPONENTIAL:                    for (i = size; ; i <<= 1)
     164           0 :                                         if ((p = (b + i)) >= t) {
     165           0 :                                                 if ((p = t - size) > b &&
     166           0 :                                                     (*cmp)(q, p TSRMLS_CC) <= sense)
     167           0 :                                                         t = p;
     168             :                                                 else
     169           0 :                                                         b = p;
     170           0 :                                                 break;
     171           0 :                                         } else if ((*cmp)(q, p TSRMLS_CC) <= sense) {
     172           0 :                                                 t = p;
     173           0 :                                                 if (i == size)
     174           0 :                                                         big = 0;
     175           0 :                                                 goto FASTCASE;
     176             :                                         } else
     177           0 :                                                 b = p;
     178           0 :                                 while (t > b+size) {
     179           0 :                                         i = (((t - b) / size) >> 1) * size;
     180           0 :                                         if ((*cmp)(q, p = b + i TSRMLS_CC) <= sense)
     181           0 :                                                 t = p;
     182             :                                         else
     183           0 :                                                 b = p;
     184             :                                 }
     185           0 :                                 goto COPY;
     186           0 : FASTCASE:                       while (i > size)
     187           0 :                                         if ((*cmp)(q,
     188             :                                                 p = b + (i >>= 1) TSRMLS_CC) <= sense)
     189           0 :                                                 t = p;
     190             :                                         else
     191           0 :                                                 b = p;
     192           0 : COPY:                           b = t;
     193             :                         }
     194           0 :                         i = size;
     195           0 :                         if (q == f1) {
     196           0 :                                 if (iflag) {
     197           0 :                                         ICOPY_LIST(f2, tp2, b);
     198           0 :                                         ICOPY_ELT(f1, tp2, i);
     199             :                                 } else {
     200           0 :                                         CCOPY_LIST(f2, tp2, b);
     201           0 :                                         CCOPY_ELT(f1, tp2, i);
     202             :                                 }
     203             :                         } else {
     204           0 :                                 if (iflag) {
     205           0 :                                         ICOPY_LIST(f1, tp2, b);
     206           0 :                                         ICOPY_ELT(f2, tp2, i);
     207             :                                 } else {
     208           0 :                                         CCOPY_LIST(f1, tp2, b);
     209           0 :                                         CCOPY_ELT(f2, tp2, i);
     210             :                                 }
     211             :                         }
     212             :                 }
     213           0 :                 if (f2 < l2) {
     214           0 :                         if (iflag)
     215           0 :                                 ICOPY_LIST(f2, tp2, l2);
     216             :                         else
     217           0 :                                 CCOPY_LIST(f2, tp2, l2);
     218           0 :                 } else if (f1 < l1) {
     219           0 :                         if (iflag)
     220           0 :                                 ICOPY_LIST(f1, tp2, l1);
     221             :                         else
     222           0 :                                 CCOPY_LIST(f1, tp2, l1);
     223             :                 }
     224           0 :                 *p1 = l2;
     225             :             }
     226           0 :             tp2 = list1;        /* swap list1, list2 */
     227           0 :             list1 = list2;
     228           0 :             list2 = tp2;
     229           0 :             last = list2 + nmemb*size;
     230             :         }
     231           0 :         if (base == list2) {
     232           0 :                 memmove(list2, list1, nmemb*size);
     233           0 :                 list2 = list1;
     234             :         }
     235           0 :         free(list2);
     236           0 :         return (0);
     237             : }
     238             : /* }}} */
     239             : 
     240             : #define swap(a, b) {                                    \
     241             :                 s = b;                                  \
     242             :                 i = size;                               \
     243             :                 do {                                    \
     244             :                         tmp = *a; *a++ = *s; *s++ = tmp; \
     245             :                 } while (--i);                          \
     246             :                 a -= size;                              \
     247             :         }
     248             : #define reverse(bot, top) {                             \
     249             :         s = top;                                        \
     250             :         do {                                            \
     251             :                 i = size;                               \
     252             :                 do {                                    \
     253             :                         tmp = *bot; *bot++ = *s; *s++ = tmp; \
     254             :                 } while (--i);                          \
     255             :                 s -= size2;                             \
     256             :         } while(bot < s);                            \
     257             : }
     258             : 
     259             : /* {{{ setup
     260             :  * Optional hybrid natural/pairwise first pass.  Eats up list1 in runs of
     261             :  * increasing order, list2 in a corresponding linked list.  Checks for runs
     262             :  * when THRESHOLD/2 pairs compare with same sense.  (Only used when NATURAL
     263             :  * is defined.  Otherwise simple pairwise merging is used.)
     264             :  */
     265           0 : static void setup(u_char *list1, u_char *list2, size_t n, size_t size, int (*cmp)(const void *, const void * TSRMLS_DC) TSRMLS_DC)
     266             : {
     267             :         size_t i, length, size2, sense;
     268             :         u_char *f1, *f2, *s, *l2, *last, *p2, tmp;
     269             : 
     270           0 :         size2 = size*2;
     271           0 :         if (n <= 5) {
     272           0 :                 insertionsort(list1, n, size, cmp TSRMLS_CC);
     273           0 :                 *EVAL(list2) = (u_char*) list2 + n*size;
     274           0 :                 return;
     275             :         }
     276             :         /*
     277             :          * Avoid running pointers out of bounds; limit n to evens
     278             :          * for simplicity.
     279             :          */
     280           0 :         i = 4 + (n & 1);
     281           0 :         insertionsort(list1 + (n - i) * size, i, size, cmp TSRMLS_CC);
     282           0 :         last = list1 + size * (n - i);
     283           0 :         *EVAL(list2 + (last - list1)) = list2 + n * size;
     284             : 
     285             : #ifdef NATURAL
     286           0 :         p2 = list2;
     287           0 :         f1 = list1;
     288           0 :         sense = (cmp(f1, f1 + size TSRMLS_CC) > 0);
     289           0 :         for (; f1 < last; sense = !sense) {
     290           0 :                 length = 2;
     291             :                                         /* Find pairs with same sense. */
     292           0 :                 for (f2 = f1 + size2; f2 < last; f2 += size2) {
     293           0 :                         if ((cmp(f2, f2+ size TSRMLS_CC) > 0) != sense)
     294           0 :                                 break;
     295           0 :                         length += 2;
     296             :                 }
     297           0 :                 if (length < THRESHOLD) {            /* Pairwise merge */
     298             :                         do {
     299           0 :                                 p2 = *EVAL(p2) = f1 + size2 - list1 + list2;
     300           0 :                                 if (sense > 0)
     301           0 :                                         swap (f1, f1 + size);
     302           0 :                         } while ((f1 += size2) < f2);
     303             :                 } else {                                /* Natural merge */
     304           0 :                         l2 = f2;
     305           0 :                         for (f2 = f1 + size2; f2 < l2; f2 += size2) {
     306           0 :                                 if ((cmp(f2-size, f2 TSRMLS_CC) > 0) != sense) {
     307           0 :                                         p2 = *EVAL(p2) = f2 - list1 + list2;
     308           0 :                                         if (sense > 0)
     309           0 :                                                 reverse(f1, f2-size);
     310           0 :                                         f1 = f2;
     311             :                                 }
     312             :                         }
     313           0 :                         if (sense > 0)
     314           0 :                                 reverse (f1, f2-size);
     315           0 :                         f1 = f2;
     316           0 :                         if (f2 < last || cmp(f2 - size, f2 TSRMLS_CC) > 0)
     317           0 :                                 p2 = *EVAL(p2) = f2 - list1 + list2;
     318             :                         else
     319           0 :                                 p2 = *EVAL(p2) = list2 + n*size;
     320             :                 }
     321             :         }
     322             : #else           /* pairwise merge only. */
     323             :         for (f1 = list1, p2 = list2; f1 < last; f1 += size2) {
     324             :                 p2 = *EVAL(p2) = p2 + size2;
     325             :                 if (cmp (f1, f1 + size TSRMLS_CC) > 0)
     326             :                         swap(f1, f1 + size);
     327             :         }
     328             : #endif /* NATURAL */
     329             : }
     330             : /* }}} */
     331             : 
     332             : /* {{{ insertionsort
     333             :  * This is to avoid out-of-bounds addresses in sorting the
     334             :  * last 4 elements.
     335             :  */
     336           0 : static void insertionsort(u_char *a, size_t n, size_t size, int (*cmp)(const void *, const void * TSRMLS_DC) TSRMLS_DC)
     337             : {
     338             :         u_char *ai, *s, *t, *u, tmp;
     339             :         size_t i;
     340             : 
     341           0 :         for (ai = a+size; --n >= 1; ai += size)
     342           0 :                 for (t = ai; t > a; t -= size) {
     343           0 :                         u = t - size;
     344           0 :                         if (cmp(u, t TSRMLS_CC) <= 0)
     345           0 :                                 break;
     346           0 :                         swap(u, t);
     347             :                 }
     348           0 : }
     349             : /* }}} */
     350             : 
     351             : /*
     352             :  * Local variables:
     353             :  * tab-width: 4
     354             :  * c-basic-offset: 4
     355             :  * End:
     356             :  * vim600: fdm=marker
     357             :  * vim: noet sw=4 ts=4
     358             :  */

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Generated at Sat, 22 Nov 2014 23:01:30 +0000 (5 days ago)

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