Browse Source
if HAVE_STRING_H. * pexecute.c, xexit.c: Include stdlib.h if HAVE_STDLIB_H. * objalloc.c: Include config.h. Include stdlib.h and don't declare malloc or free if HAVE_STDLIB_H. * strerror.c, strsignal.c: Include stdlib.h if HAVE_STDLIB_H, else declare malloc without prototype. Include string.h if HAVE_STRING_H, else declare memset without prototype. Don't include stddef.h. * sort.c: Bring over from GCC.binutils-2_11-branch
Zack Weinberg
27 years ago
10 changed files with 245 additions and 16 deletions
@ -0,0 +1,185 @@ |
|||
/* 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 |
|||
Loading…
Reference in new issue