--- /dev/null
+/* Sorting algorithms.
+ Copyright (C) 2000 Free Software Foundation, Inc.
+ Contributed by Mark Mitchell <mark@codesourcery.com>.
+
+This file is part of GNU CC.
+
+GNU CC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU CC is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU CC; see the file COPYING. If not, write to
+the Free Software Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "libiberty.h"
+#include "sort.h"
+#include <limits.h>
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+
+#ifndef UCHAR_MAX
+#define UCHAR_MAX ((unsigned char)(-1))
+#endif
+
+/* POINTERS and WORK are both arrays of N pointers. When this
+ function returns POINTERS will be sorted in ascending order. */
+
+void sort_pointers (n, pointers, work)
+ size_t n;
+ void **pointers;
+ void **work;
+{
+ /* The type of a single digit. This can be any unsigned integral
+ type. When changing this, DIGIT_MAX should be changed as
+ well. */
+ typedef unsigned char digit_t;
+
+ /* The maximum value a single digit can have. */
+#define DIGIT_MAX (UCHAR_MAX + 1)
+
+ /* The Ith entry is the number of elements in *POINTERSP that have I
+ in the digit on which we are currently sorting. */
+ unsigned int count[DIGIT_MAX];
+ /* Nonzero if we are running on a big-endian machine. */
+ int big_endian_p;
+ size_t i;
+ size_t j;
+
+ /* The algorithm used here is radix sort which takes time linear in
+ the number of elements in the array. */
+
+ /* The algorithm here depends on being able to swap the two arrays
+ an even number of times. */
+ if ((sizeof (void *) / sizeof (digit_t)) % 2 != 0)
+ abort ();
+
+ /* Figure out the endianness of the machine. */
+ for (i = 0, j = 0; i < sizeof (size_t); ++i)
+ {
+ j *= (UCHAR_MAX + 1);
+ j += i;
+ }
+ big_endian_p = (((char *)&j)[0] == 0);
+
+ /* Move through the pointer values from least significant to most
+ significant digits. */
+ for (i = 0; i < sizeof (void *) / sizeof (digit_t); ++i)
+ {
+ digit_t *digit;
+ digit_t *bias;
+ digit_t *top;
+ unsigned int *countp;
+ void **pointerp;
+
+ /* The offset from the start of the pointer will depend on the
+ endianness of the machine. */
+ if (big_endian_p)
+ j = sizeof (void *) / sizeof (digit_t) - i;
+ else
+ j = i;
+
+ /* Now, perform a stable sort on this digit. We use counting
+ sort. */
+ memset (count, 0, DIGIT_MAX * sizeof (unsigned int));
+
+ /* Compute the address of the appropriate digit in the first and
+ one-past-the-end elements of the array. On a little-endian
+ machine, the least-significant digit is closest to the front. */
+ bias = ((digit_t *) pointers) + j;
+ top = ((digit_t *) (pointers + n)) + j;
+
+ /* Count how many there are of each value. At the end of this
+ loop, COUNT[K] will contain the number of pointers whose Ith
+ digit is K. */
+ for (digit = bias;
+ digit < top;
+ digit += sizeof (void *) / sizeof (digit_t))
+ ++count[*digit];
+
+ /* Now, make COUNT[K] contain the number of pointers whose Ith
+ digit is less than or equal to K. */
+ for (countp = count + 1; countp < count + DIGIT_MAX; ++countp)
+ *countp += countp[-1];
+
+ /* Now, drop the pointers into their correct locations. */
+ for (pointerp = pointers + n - 1; pointerp >= pointers; --pointerp)
+ work[--count[((digit_t *) pointerp)[j]]] = *pointerp;
+
+ /* Swap WORK and POINTERS so that POINTERS contains the sorted
+ array. */
+ pointerp = pointers;
+ pointers = work;
+ work = pointerp;
+ }
+}
+
+/* Everything below here is a unit test for the routines in this
+ file. */
+
+#ifdef UNIT_TEST
+
+#include <stdio.h>
+
+void *xmalloc (n)
+ size_t n;
+{
+ return malloc (n);
+}
+
+int main (int argc, char **argv)
+{
+ int k;
+ int result;
+ size_t i;
+ void **pointers;
+ void **work;
+
+ if (argc > 1)
+ k = atoi (argv[1]);
+ else
+ k = 10;
+
+ pointers = xmalloc (k * sizeof (void *));
+ work = xmalloc (k * sizeof (void *));
+
+ for (i = 0; i < k; ++i)
+ {
+ pointers[i] = (void *) random ();
+ printf ("%x\n", pointers[i]);
+ }
+
+ sort_pointers (k, pointers, work);
+
+ printf ("\nSorted\n\n");
+
+ result = 0;
+
+ for (i = 0; i < k; ++i)
+ {
+ printf ("%x\n", pointers[i]);
+ if (i > 0 && (char*) pointers[i] < (char*) pointers[i - 1])
+ result = 1;
+ }
+
+ free (pointers);
+ free (work);
+
+ return result;
+}
+
+#endif
projects / binutils-gdb.git / commitdiff