| /* |
| * mergesort() implementation for systems that don't have it. |
| * |
| * Copyright (c) 1992, 1993 |
| * The Regents of the University of California. All rights reserved. |
| * |
| * This code is derived from software contributed to Berkeley by |
| * Peter McIlroy. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of the University nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| #include "util.h" |
| |
| #if defined(LIBC_SCCS) && !defined(lint) |
| static char sccsid[] = "@(#)merge.c 8.2 (Berkeley) 2/14/94"; |
| #endif /* LIBC_SCCS and not lint */ |
| |
| #ifdef HAVE_MERGESORT |
| #undef yasm__mergesort |
| #endif |
| |
| #ifndef HAVE_MERGESORT |
| /* |
| * Hybrid exponential search/linear search merge sort with hybrid |
| * natural/pairwise first pass. Requires about .3% more comparisons |
| * for random data than LSMS with pairwise first pass alone. |
| * It works for objects as small as two bytes. |
| */ |
| |
| #define NATURAL |
| #define THRESHOLD 16 /* Best choice for natural merge cut-off. */ |
| |
| /* #define NATURAL to get hybrid natural merge. |
| * (The default is pairwise merging.) |
| */ |
| |
| #include <errno.h> |
| #include <string.h> |
| |
| static void setup(unsigned char *, unsigned char *, size_t, size_t, |
| int (*)(const void *, const void *)); |
| static void insertionsort(unsigned char *, size_t, size_t, |
| int (*)(const void *, const void *)); |
| |
| #define ISIZE sizeof(int) |
| #define PSIZE sizeof(unsigned char *) |
| #define ICOPY_LIST(src, dst, last) \ |
| do \ |
| *(int*)dst = *(int*)src, src += ISIZE, dst += ISIZE; \ |
| while(src < last) |
| #define ICOPY_ELT(src, dst, i) \ |
| do \ |
| *(int*) dst = *(int*) src, src += ISIZE, dst += ISIZE; \ |
| while (i -= ISIZE) |
| |
| #define CCOPY_LIST(src, dst, last) \ |
| do \ |
| *dst++ = *src++; \ |
| while (src < last) |
| #define CCOPY_ELT(src, dst, i) \ |
| do \ |
| *dst++ = *src++; \ |
| while (i -= 1) |
| |
| /* |
| * Find the next possible pointer head. (Trickery for forcing an array |
| * to do double duty as a linked list when objects do not align with word |
| * boundaries. |
| */ |
| /* Assumption: PSIZE is a power of 2. */ |
| #define EVAL(p) (unsigned char **) \ |
| ((unsigned char *)0 + \ |
| (((unsigned char *)p + PSIZE - 1 - (unsigned char *) 0) & ~(PSIZE - 1))) |
| #endif /*HAVE_MERGESORT*/ |
| |
| /* |
| * Arguments are as for qsort. |
| */ |
| int |
| yasm__mergesort(void *base, size_t nmemb, size_t size, |
| int (*cmp)(const void *, const void *)) |
| { |
| #ifdef HAVE_MERGESORT |
| return mergesort(base, nmemb, size, cmp); |
| #else |
| size_t i; |
| int sense; |
| int big, iflag; |
| unsigned char *f1, *f2, *t, *b, *tp2, *q, *l1, *l2; |
| unsigned char *list2, *list1, *p2, *p, *last, **p1; |
| |
| if (size < PSIZE / 2) { /* Pointers must fit into 2 * size. */ |
| #ifdef EINVAL |
| errno = EINVAL; |
| #endif |
| return (-1); |
| } |
| |
| if (nmemb == 0) |
| return (0); |
| |
| /* |
| * XXX |
| * Stupid subtraction for the Cray. |
| */ |
| iflag = 0; |
| if (!(size % ISIZE) && !(((char *)base - (char *)0) % ISIZE)) |
| iflag = 1; |
| |
| if ((list2 = yasm_xmalloc(nmemb * size + PSIZE)) == NULL) |
| return (-1); |
| |
| list1 = base; |
| setup(list1, list2, nmemb, size, cmp); |
| last = list2 + nmemb * size; |
| i = 0; |
| big = 0; |
| while (*EVAL(list2) != last) { |
| l2 = list1; |
| p1 = EVAL(list1); |
| for (tp2 = p2 = list2; p2 != last; p1 = EVAL(l2)) { |
| p2 = *EVAL(p2); |
| f1 = l2; |
| f2 = l1 = list1 + (p2 - list2); |
| if (p2 != last) |
| p2 = *EVAL(p2); |
| l2 = list1 + (p2 - list2); |
| while (f1 < l1 && f2 < l2) { |
| if ((*cmp)(f1, f2) <= 0) { |
| q = f2; |
| b = f1, t = l1; |
| sense = -1; |
| } else { |
| q = f1; |
| b = f2, t = l2; |
| sense = 0; |
| } |
| if (!big) { /* here i = 0 */ |
| while ((b += size) < t && cmp(q, b) >sense) |
| if (++i == 6) { |
| big = 1; |
| goto EXPONENTIAL; |
| } |
| } else { |
| EXPONENTIAL: for (i = size; ; i <<= 1) |
| if ((p = (b + i)) >= t) { |
| if ((p = t - size) > b && |
| (*cmp)(q, p) <= sense) |
| t = p; |
| else |
| b = p; |
| break; |
| } else if ((*cmp)(q, p) <= sense) { |
| t = p; |
| if (i == size) |
| big = 0; |
| goto FASTCASE; |
| } else |
| b = p; |
| while (t > b+size) { |
| i = (((t - b) / size) >> 1) * size; |
| if ((*cmp)(q, p = b + i) <= sense) |
| t = p; |
| else |
| b = p; |
| } |
| goto COPY; |
| FASTCASE: while (i > size) |
| if ((*cmp)(q, |
| p = b + (i >>= 1)) <= sense) |
| t = p; |
| else |
| b = p; |
| COPY: b = t; |
| } |
| i = size; |
| if (q == f1) { |
| if (iflag) { |
| ICOPY_LIST(f2, tp2, b); |
| ICOPY_ELT(f1, tp2, i); |
| } else { |
| CCOPY_LIST(f2, tp2, b); |
| CCOPY_ELT(f1, tp2, i); |
| } |
| } else { |
| if (iflag) { |
| ICOPY_LIST(f1, tp2, b); |
| ICOPY_ELT(f2, tp2, i); |
| } else { |
| CCOPY_LIST(f1, tp2, b); |
| CCOPY_ELT(f2, tp2, i); |
| } |
| } |
| } |
| if (f2 < l2) { |
| if (iflag) |
| ICOPY_LIST(f2, tp2, l2); |
| else |
| CCOPY_LIST(f2, tp2, l2); |
| } else if (f1 < l1) { |
| if (iflag) |
| ICOPY_LIST(f1, tp2, l1); |
| else |
| CCOPY_LIST(f1, tp2, l1); |
| } |
| *p1 = l2; |
| } |
| tp2 = list1; /* swap list1, list2 */ |
| list1 = list2; |
| list2 = tp2; |
| last = list2 + nmemb*size; |
| } |
| if (base == list2) { |
| memmove(list2, list1, nmemb*size); |
| list2 = list1; |
| } |
| yasm_xfree(list2); |
| return (0); |
| #endif /*HAVE_MERGESORT*/ |
| } |
| |
| #ifndef HAVE_MERGESORT |
| |
| #define swap(a, b) { \ |
| s = b; \ |
| i = size; \ |
| do { \ |
| tmp = *a; *a++ = *s; *s++ = tmp; \ |
| } while (--i); \ |
| a -= size; \ |
| } |
| #define reverse(bot, top) { \ |
| s = top; \ |
| do { \ |
| i = size; \ |
| do { \ |
| tmp = *bot; *bot++ = *s; *s++ = tmp; \ |
| } while (--i); \ |
| s -= size2; \ |
| } while(bot < s); \ |
| } |
| |
| /* |
| * Optional hybrid natural/pairwise first pass. Eats up list1 in runs of |
| * increasing order, list2 in a corresponding linked list. Checks for runs |
| * when THRESHOLD/2 pairs compare with same sense. (Only used when NATURAL |
| * is defined. Otherwise simple pairwise merging is used.) |
| */ |
| void |
| setup(unsigned char *list1, unsigned char *list2, size_t n, size_t size, |
| int (*cmp)(const void *, const void *)) |
| { |
| size_t i; |
| unsigned int tmp; |
| int length, sense; |
| size_t size2; |
| unsigned char *f1, *f2, *s, *l2, *last, *p2; |
| |
| size2 = size*2; |
| if (n <= 5) { |
| insertionsort(list1, n, size, cmp); |
| *EVAL(list2) = (unsigned char*) list2 + n*size; |
| return; |
| } |
| /* |
| * Avoid running pointers out of bounds; limit n to evens |
| * for simplicity. |
| */ |
| i = 4 + (n & 1); |
| insertionsort(list1 + (n - i) * size, i, size, cmp); |
| last = list1 + size * (n - i); |
| *EVAL(list2 + (last - list1)) = list2 + n * size; |
| |
| #ifdef NATURAL |
| p2 = list2; |
| f1 = list1; |
| sense = (cmp(f1, f1 + size) > 0); |
| for (; f1 < last; sense = !sense) { |
| length = 2; |
| /* Find pairs with same sense. */ |
| for (f2 = f1 + size2; f2 < last; f2 += size2) { |
| if ((cmp(f2, f2+ size) > 0) != sense) |
| break; |
| length += 2; |
| } |
| if (length < THRESHOLD) { /* Pairwise merge */ |
| do { |
| p2 = *EVAL(p2) = f1 + size2 - list1 + list2; |
| if (sense > 0) |
| swap (f1, f1 + size); |
| } while ((f1 += size2) < f2); |
| } else { /* Natural merge */ |
| l2 = f2; |
| for (f2 = f1 + size2; f2 < l2; f2 += size2) { |
| if ((cmp(f2-size, f2) > 0) != sense) { |
| p2 = *EVAL(p2) = f2 - list1 + list2; |
| if (sense > 0) |
| reverse(f1, f2-size); |
| f1 = f2; |
| } |
| } |
| if (sense > 0) |
| reverse (f1, f2-size); |
| f1 = f2; |
| if (f2 < last || cmp(f2 - size, f2) > 0) |
| p2 = *EVAL(p2) = f2 - list1 + list2; |
| else |
| p2 = *EVAL(p2) = list2 + n*size; |
| } |
| } |
| #else /* pairwise merge only. */ |
| for (f1 = list1, p2 = list2; f1 < last; f1 += size2) { |
| p2 = *EVAL(p2) = p2 + size2; |
| if (cmp (f1, f1 + size) > 0) |
| swap(f1, f1 + size); |
| } |
| #endif /* NATURAL */ |
| } |
| |
| /* |
| * This is to avoid out-of-bounds addresses in sorting the |
| * last 4 elements. |
| */ |
| static void |
| insertionsort(unsigned char *a, size_t n, size_t size, |
| int (*cmp)(const void *, const void *)) |
| { |
| unsigned char *ai, *s, *t, *u, tmp; |
| size_t i; |
| |
| for (ai = a+size; --n >= 1; ai += size) |
| for (t = ai; t > a; t -= size) { |
| u = t - size; |
| if (cmp(u, t) <= 0) |
| break; |
| swap(u, t); |
| } |
| } |
| #endif /*HAVE_MERGESORT*/ |
