/* Sorting algorithms.
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/* Sorting algorithms.
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Copyright (C) 2000 Free Software Foundation, Inc.
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Copyright (C) 2000 Free Software Foundation, Inc.
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Contributed by Mark Mitchell <mark@codesourcery.com>.
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Contributed by Mark Mitchell <mark@codesourcery.com>.
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This file is part of GNU CC.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify it
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GNU CC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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any later version.
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GNU CC is distributed in the hope that it will be useful, but
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GNU CC is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street - Fifth Floor,
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the Free Software Foundation, 51 Franklin Street - Fifth Floor,
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Boston, MA 02110-1301, USA. */
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Boston, MA 02110-1301, USA. */
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#ifdef HAVE_CONFIG_H
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#include "config.h"
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#endif
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#endif
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#include "libiberty.h"
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#include "libiberty.h"
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#include "sort.h"
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#include "sort.h"
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#ifdef HAVE_LIMITS_H
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#ifdef HAVE_LIMITS_H
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#include <limits.h>
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#include <limits.h>
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#endif
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#endif
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#ifdef HAVE_SYS_PARAM_H
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#ifdef HAVE_SYS_PARAM_H
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#include <sys/param.h>
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#include <sys/param.h>
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#endif
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#endif
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#ifdef HAVE_STDLIB_H
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#include <stdlib.h>
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#endif
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#endif
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#ifdef HAVE_STRING_H
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#ifdef HAVE_STRING_H
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#include <string.h>
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#include <string.h>
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#endif
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#endif
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#ifndef UCHAR_MAX
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#ifndef UCHAR_MAX
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#define UCHAR_MAX ((unsigned char)(-1))
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#define UCHAR_MAX ((unsigned char)(-1))
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#endif
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#endif
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/* POINTERS and WORK are both arrays of N pointers. When this
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/* POINTERS and WORK are both arrays of N pointers. When this
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function returns POINTERS will be sorted in ascending order. */
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function returns POINTERS will be sorted in ascending order. */
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void sort_pointers (size_t n, void **pointers, void **work)
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void sort_pointers (size_t n, void **pointers, void **work)
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{
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{
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/* The type of a single digit. This can be any unsigned integral
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/* The type of a single digit. This can be any unsigned integral
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type. When changing this, DIGIT_MAX should be changed as
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type. When changing this, DIGIT_MAX should be changed as
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well. */
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well. */
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typedef unsigned char digit_t;
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typedef unsigned char digit_t;
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/* The maximum value a single digit can have. */
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/* The maximum value a single digit can have. */
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#define DIGIT_MAX (UCHAR_MAX + 1)
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#define DIGIT_MAX (UCHAR_MAX + 1)
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/* The Ith entry is the number of elements in *POINTERSP that have I
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/* The Ith entry is the number of elements in *POINTERSP that have I
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in the digit on which we are currently sorting. */
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in the digit on which we are currently sorting. */
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unsigned int count[DIGIT_MAX];
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unsigned int count[DIGIT_MAX];
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/* Nonzero if we are running on a big-endian machine. */
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/* Nonzero if we are running on a big-endian machine. */
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int big_endian_p;
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int big_endian_p;
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size_t i;
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size_t i;
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size_t j;
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size_t j;
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/* The algorithm used here is radix sort which takes time linear in
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/* The algorithm used here is radix sort which takes time linear in
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the number of elements in the array. */
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the number of elements in the array. */
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/* The algorithm here depends on being able to swap the two arrays
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/* The algorithm here depends on being able to swap the two arrays
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an even number of times. */
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an even number of times. */
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if ((sizeof (void *) / sizeof (digit_t)) % 2 != 0)
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if ((sizeof (void *) / sizeof (digit_t)) % 2 != 0)
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abort ();
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abort ();
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/* Figure out the endianness of the machine. */
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/* Figure out the endianness of the machine. */
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for (i = 0, j = 0; i < sizeof (size_t); ++i)
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for (i = 0, j = 0; i < sizeof (size_t); ++i)
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{
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{
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j *= (UCHAR_MAX + 1);
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j *= (UCHAR_MAX + 1);
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j += i;
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j += i;
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}
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}
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big_endian_p = (((char *)&j)[0] == 0);
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big_endian_p = (((char *)&j)[0] == 0);
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/* Move through the pointer values from least significant to most
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/* Move through the pointer values from least significant to most
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significant digits. */
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significant digits. */
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for (i = 0; i < sizeof (void *) / sizeof (digit_t); ++i)
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for (i = 0; i < sizeof (void *) / sizeof (digit_t); ++i)
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{
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{
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digit_t *digit;
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digit_t *digit;
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digit_t *bias;
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digit_t *bias;
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digit_t *top;
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digit_t *top;
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unsigned int *countp;
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unsigned int *countp;
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void **pointerp;
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void **pointerp;
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/* The offset from the start of the pointer will depend on the
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/* The offset from the start of the pointer will depend on the
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endianness of the machine. */
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endianness of the machine. */
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if (big_endian_p)
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if (big_endian_p)
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j = sizeof (void *) / sizeof (digit_t) - i;
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j = sizeof (void *) / sizeof (digit_t) - i;
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else
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else
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j = i;
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j = i;
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/* Now, perform a stable sort on this digit. We use counting
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/* Now, perform a stable sort on this digit. We use counting
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sort. */
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sort. */
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memset (count, 0, DIGIT_MAX * sizeof (unsigned int));
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memset (count, 0, DIGIT_MAX * sizeof (unsigned int));
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/* Compute the address of the appropriate digit in the first and
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/* Compute the address of the appropriate digit in the first and
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one-past-the-end elements of the array. On a little-endian
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one-past-the-end elements of the array. On a little-endian
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machine, the least-significant digit is closest to the front. */
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machine, the least-significant digit is closest to the front. */
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bias = ((digit_t *) pointers) + j;
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bias = ((digit_t *) pointers) + j;
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top = ((digit_t *) (pointers + n)) + j;
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top = ((digit_t *) (pointers + n)) + j;
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/* Count how many there are of each value. At the end of this
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/* Count how many there are of each value. At the end of this
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loop, COUNT[K] will contain the number of pointers whose Ith
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loop, COUNT[K] will contain the number of pointers whose Ith
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digit is K. */
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digit is K. */
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for (digit = bias;
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for (digit = bias;
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digit < top;
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digit < top;
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digit += sizeof (void *) / sizeof (digit_t))
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digit += sizeof (void *) / sizeof (digit_t))
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++count[*digit];
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++count[*digit];
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/* Now, make COUNT[K] contain the number of pointers whose Ith
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/* Now, make COUNT[K] contain the number of pointers whose Ith
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digit is less than or equal to K. */
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digit is less than or equal to K. */
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for (countp = count + 1; countp < count + DIGIT_MAX; ++countp)
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for (countp = count + 1; countp < count + DIGIT_MAX; ++countp)
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*countp += countp[-1];
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*countp += countp[-1];
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/* Now, drop the pointers into their correct locations. */
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/* Now, drop the pointers into their correct locations. */
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for (pointerp = pointers + n - 1; pointerp >= pointers; --pointerp)
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for (pointerp = pointers + n - 1; pointerp >= pointers; --pointerp)
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work[--count[((digit_t *) pointerp)[j]]] = *pointerp;
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work[--count[((digit_t *) pointerp)[j]]] = *pointerp;
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/* Swap WORK and POINTERS so that POINTERS contains the sorted
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/* Swap WORK and POINTERS so that POINTERS contains the sorted
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array. */
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array. */
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pointerp = pointers;
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pointerp = pointers;
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pointers = work;
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pointers = work;
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work = pointerp;
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work = pointerp;
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}
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}
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}
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}
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/* Everything below here is a unit test for the routines in this
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/* Everything below here is a unit test for the routines in this
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file. */
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file. */
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#ifdef UNIT_TEST
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#ifdef UNIT_TEST
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#include <stdio.h>
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#include <stdio.h>
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void *xmalloc (size_t n)
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void *xmalloc (size_t n)
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{
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{
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return malloc (n);
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return malloc (n);
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}
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}
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int main (int argc, char **argv)
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int main (int argc, char **argv)
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{
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{
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int k;
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int k;
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int result;
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int result;
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size_t i;
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size_t i;
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void **pointers;
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void **pointers;
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void **work;
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void **work;
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if (argc > 1)
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if (argc > 1)
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k = atoi (argv[1]);
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k = atoi (argv[1]);
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else
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else
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k = 10;
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k = 10;
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pointers = XNEWVEC (void*, k);
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pointers = XNEWVEC (void*, k);
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work = XNEWVEC (void*, k);
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work = XNEWVEC (void*, k);
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for (i = 0; i < k; ++i)
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for (i = 0; i < k; ++i)
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{
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{
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pointers[i] = (void *) random ();
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pointers[i] = (void *) random ();
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printf ("%x\n", pointers[i]);
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printf ("%x\n", pointers[i]);
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}
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}
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sort_pointers (k, pointers, work);
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sort_pointers (k, pointers, work);
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printf ("\nSorted\n\n");
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printf ("\nSorted\n\n");
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result = 0;
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result = 0;
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for (i = 0; i < k; ++i)
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for (i = 0; i < k; ++i)
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{
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{
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printf ("%x\n", pointers[i]);
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printf ("%x\n", pointers[i]);
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if (i > 0 && (char*) pointers[i] < (char*) pointers[i - 1])
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if (i > 0 && (char*) pointers[i] < (char*) pointers[i - 1])
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result = 1;
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result = 1;
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}
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}
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free (pointers);
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free (pointers);
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free (work);
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free (work);
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return result;
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return result;
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}
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}
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#endif
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#endif
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