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Add new radixsort and sradixsort functions

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Taken from FreeBSD.
This commit is contained in:
Guillem Jover
2011-02-25 18:48:10 +01:00
parent c766e58acf
commit 4b95e82a32
6 changed files with 497 additions and 0 deletions
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3
Makefile
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@@ -44,6 +44,7 @@ LIB_SRCS := \
fmtcheck.c \
nlist.c \
progname.c \
radixsort.c \
vis.c unvis.c \
$(LIB_SRCS_GEN)
LIB_SRCS_GEN := $(patsubst %,src/%,$(LIB_SRCS_GEN))
@@ -93,6 +94,8 @@ LIB_MANS := \
humanize_number.3 \
fmtcheck.3 \
mergesort.3 \
radixsort.3 \
sradixsort.3 \
nlist.3 \
pidfile.3 \
setmode.3 \

2
Versions
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@@ -70,5 +70,7 @@ LIBBSD_0.3 {
getpeereid;
mergesort;
radixsort;
sradixsort;
} LIBBSD_0.2;

4
include/bsd/stdlib.h
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@@ -54,6 +54,10 @@ void setprogname(const char *);
int heapsort (void *, size_t, size_t, int (*)(const void *, const void *));
int mergesort(void *base, size_t nmemb, size_t size,
int (*cmp)(const void *, const void *));
int radixsort(const unsigned char **base, int nmemb,
const unsigned char *table, unsigned endbyte);
int sradixsort(const unsigned char **base, int nmemb,
const unsigned char *table, unsigned endbyte);
void *reallocf(void *ptr, size_t size);

160
src/radixsort.3 Normal file
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@@ -0,0 +1,160 @@
.\" Copyright (c) 1990, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" 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.
.\" 4. 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.
.\"
.\" @(#)radixsort.3 8.2 (Berkeley) 1/27/94
.\" $FreeBSD$
.\"
.Dd January 27, 1994
.Dt RADIXSORT 3
.Os
.Sh NAME
.Nm radixsort , sradixsort
.Nd radix sort
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In limits.h
.In stdlib.h
.Ft int
.Fn radixsort "const unsigned char **base" "int nmemb" "const unsigned char *table" "unsigned endbyte"
.Ft int
.Fn sradixsort "const unsigned char **base" "int nmemb" "const unsigned char *table" "unsigned endbyte"
.Sh DESCRIPTION
The
.Fn radixsort
and
.Fn sradixsort
functions
are implementations of radix sort.
.Pp
These functions sort an array of pointers to byte strings, the initial
member of which is referenced by
.Fa base .
The byte strings may contain any values; the end of each string
is denoted by the user-specified value
.Fa endbyte .
.Pp
Applications may specify a sort order by providing the
.Fa table
argument.
If
.Pf non- Dv NULL ,
.Fa table
must reference an array of
.Dv UCHAR_MAX
+ 1 bytes which contains the sort
weight of each possible byte value.
The end-of-string byte must have a sort weight of 0 or 255
(for sorting in reverse order).
More than one byte may have the same sort weight.
The
.Fa table
argument
is useful for applications which wish to sort different characters
equally, for example, providing a table with the same weights
for A-Z as for a-z will result in a case-insensitive sort.
If
.Fa table
is NULL, the contents of the array are sorted in ascending order
according to the
.Tn ASCII
order of the byte strings they reference and
.Fa endbyte
has a sorting weight of 0.
.Pp
The
.Fn sradixsort
function is stable, that is, if two elements compare as equal, their
order in the sorted array is unchanged.
The
.Fn sradixsort
function uses additional memory sufficient to hold
.Fa nmemb
pointers.
.Pp
The
.Fn radixsort
function is not stable, but uses no additional memory.
.Pp
These functions are variants of most-significant-byte radix sorting; in
particular, see
.An "D.E. Knuth" Ns 's
.%T "Algorithm R"
and section 5.2.5, exercise 10.
They take linear time relative to the number of bytes in the strings.
.Sh RETURN VALUES
.Rv -std radixsort
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EINVAL
The value of the
.Fa endbyte
element of
.Fa table
is not 0 or 255.
.El
.Pp
Additionally, the
.Fn sradixsort
function
may fail and set
.Va errno
for any of the errors specified for the library routine
.Xr malloc 3 .
.Sh SEE ALSO
.Xr sort 1 ,
.Xr qsort 3
.Pp
.Rs
.%A Knuth, D.E.
.%D 1968
.%B "The Art of Computer Programming"
.%T "Sorting and Searching"
.%V Vol. 3
.%P pp. 170-178
.Re
.Rs
.%A Paige, R.
.%D 1987
.%T "Three Partition Refinement Algorithms"
.%J "SIAM J. Comput."
.%V Vol. 16
.%N No. 6
.Re
.Rs
.%A McIlroy, P.
.%D 1993
.%B "Engineering Radix Sort"
.%T "Computing Systems"
.%V Vol. 6:1
.%P pp. 5-27
.Re
.Sh HISTORY
The
.Fn radixsort
function first appeared in
.Bx 4.4 .

327
src/radixsort.c Normal file
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@@ -0,0 +1,327 @@
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Peter McIlroy and by Dan Bernstein at New York University,
*
* 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.
* 4. 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)radixsort.c 8.2 (Berkeley) 4/28/95";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Radixsort routines.
*
* Program r_sort_a() is unstable but uses O(logN) extra memory for a stack.
* Use radixsort(a, n, trace, endchar) for this case.
*
* For stable sorting (using N extra pointers) use sradixsort(), which calls
* r_sort_b().
*
* For a description of this code, see D. McIlroy, P. McIlroy, K. Bostic,
* "Engineering Radix Sort".
*/
#include <sys/types.h>
#include <stdlib.h>
#include <stddef.h>
#include <errno.h>
typedef struct {
const u_char **sa;
int sn, si;
} stack;
static inline void simplesort
(const u_char **, int, int, const u_char *, u_int);
static void r_sort_a(const u_char **, int, int, const u_char *, u_int);
static void r_sort_b(const u_char **, const u_char **, int, int,
const u_char *, u_int);
#define THRESHOLD 20 /* Divert to simplesort(). */
#define SIZE 512 /* Default stack size. */
#define SETUP { \
if (tab == NULL) { \
tr = tr0; \
for (c = 0; c < endch; c++) \
tr0[c] = c + 1; \
tr0[c] = 0; \
for (c++; c < 256; c++) \
tr0[c] = c; \
endch = 0; \
} else { \
endch = tab[endch]; \
tr = tab; \
if (endch != 0 && endch != 255) { \
errno = EINVAL; \
return (-1); \
} \
} \
}
int
radixsort(a, n, tab, endch)
const u_char **a, *tab;
int n;
u_int endch;
{
const u_char *tr;
int c;
u_char tr0[256];
SETUP;
r_sort_a(a, n, 0, tr, endch);
return (0);
}
int
sradixsort(a, n, tab, endch)
const u_char **a, *tab;
int n;
u_int endch;
{
const u_char *tr, **ta;
int c;
u_char tr0[256];
SETUP;
if (n < THRESHOLD)
simplesort(a, n, 0, tr, endch);
else {
if ((ta = malloc(n * sizeof(a))) == NULL)
return (-1);
r_sort_b(a, ta, n, 0, tr, endch);
free(ta);
}
return (0);
}
#define empty(s) (s >= sp)
#define pop(a, n, i) a = (--sp)->sa, n = sp->sn, i = sp->si
#define push(a, n, i) sp->sa = a, sp->sn = n, (sp++)->si = i
#define swap(a, b, t) t = a, a = b, b = t
/* Unstable, in-place sort. */
static void
r_sort_a(a, n, i, tr, endch)
const u_char **a;
int n, i;
const u_char *tr;
u_int endch;
{
static int count[256], nc, bmin;
int c;
const u_char **ak, *r;
stack s[SIZE], *sp, *sp0, *sp1, temp;
int *cp, bigc;
const u_char **an, *t, **aj, **top[256];
/* Set up stack. */
sp = s;
push(a, n, i);
while (!empty(s)) {
pop(a, n, i);
if (n < THRESHOLD) {
simplesort(a, n, i, tr, endch);
continue;
}
an = a + n;
/* Make character histogram. */
if (nc == 0) {
bmin = 255; /* First occupied bin, excluding eos. */
for (ak = a; ak < an;) {
c = tr[(*ak++)[i]];
if (++count[c] == 1 && c != endch) {
if (c < bmin)
bmin = c;
nc++;
}
}
if (sp + nc > s + SIZE) { /* Get more stack. */
r_sort_a(a, n, i, tr, endch);
continue;
}
}
/*
* Special case: if all strings have the same
* character at position i, move on to the next
* character.
*/
if (nc == 1 && count[bmin] == n) {
push(a, n, i+1);
nc = count[bmin] = 0;
continue;
}
/*
* Set top[]; push incompletely sorted bins onto stack.
* top[] = pointers to last out-of-place element in bins.
* count[] = counts of elements in bins.
* Before permuting: top[c-1] + count[c] = top[c];
* during deal: top[c] counts down to top[c-1].
*/
sp0 = sp1 = sp; /* Stack position of biggest bin. */
bigc = 2; /* Size of biggest bin. */
if (endch == 0) /* Special case: set top[eos]. */
top[0] = ak = a + count[0];
else {
ak = a;
top[255] = an;
}
for (cp = count + bmin; nc > 0; cp++) {
while (*cp == 0) /* Find next non-empty pile. */
cp++;
if (*cp > 1) {
if (*cp > bigc) {
bigc = *cp;
sp1 = sp;
}
push(ak, *cp, i+1);
}
top[cp-count] = ak += *cp;
nc--;
}
swap(*sp0, *sp1, temp); /* Play it safe -- biggest bin last. */
/*
* Permute misplacements home. Already home: everything
* before aj, and in bin[c], items from top[c] on.
* Inner loop:
* r = next element to put in place;
* ak = top[r[i]] = location to put the next element.
* aj = bottom of 1st disordered bin.
* Outer loop:
* Once the 1st disordered bin is done, ie. aj >= ak,
* aj<-aj + count[c] connects the bins in a linked list;
* reset count[c].
*/
for (aj = a; aj < an; *aj = r, aj += count[c], count[c] = 0)
for (r = *aj; aj < (ak = --top[c = tr[r[i]]]);)
swap(*ak, r, t);
}
}
/* Stable sort, requiring additional memory. */
static void
r_sort_b(a, ta, n, i, tr, endch)
const u_char **a, **ta;
int n, i;
const u_char *tr;
u_int endch;
{
static int count[256], nc, bmin;
int c;
const u_char **ak, **ai;
stack s[512], *sp, *sp0, *sp1, temp;
const u_char **top[256];
int *cp, bigc;
sp = s;
push(a, n, i);
while (!empty(s)) {
pop(a, n, i);
if (n < THRESHOLD) {
simplesort(a, n, i, tr, endch);
continue;
}
if (nc == 0) {
bmin = 255;
for (ak = a + n; --ak >= a;) {
c = tr[(*ak)[i]];
if (++count[c] == 1 && c != endch) {
if (c < bmin)
bmin = c;
nc++;
}
}
if (sp + nc > s + SIZE) {
r_sort_b(a, ta, n, i, tr, endch);
continue;
}
}
sp0 = sp1 = sp;
bigc = 2;
if (endch == 0) {
top[0] = ak = a + count[0];
count[0] = 0;
} else {
ak = a;
top[255] = a + n;
count[255] = 0;
}
for (cp = count + bmin; nc > 0; cp++) {
while (*cp == 0)
cp++;
if ((c = *cp) > 1) {
if (c > bigc) {
bigc = c;
sp1 = sp;
}
push(ak, c, i+1);
}
top[cp-count] = ak += c;
*cp = 0; /* Reset count[]. */
nc--;
}
swap(*sp0, *sp1, temp);
for (ak = ta + n, ai = a+n; ak > ta;) /* Copy to temp. */
*--ak = *--ai;
for (ak = ta+n; --ak >= ta;) /* Deal to piles. */
*--top[tr[(*ak)[i]]] = *ak;
}
}
static inline void
simplesort(a, n, b, tr, endch) /* insertion sort */
const u_char **a;
int n, b;
const u_char *tr;
u_int endch;
{
u_char ch;
const u_char **ak, **ai, *s, *t;
for (ak = a+1; --n >= 1; ak++)
for (ai = ak; ai > a; ai--) {
for (s = ai[0] + b, t = ai[-1] + b;
(ch = tr[*s]) != endch; s++, t++)
if (ch != tr[*t])
break;
if (ch >= tr[*t])
break;
swap(ai[0], ai[-1], s);
}
}

1
src/sradixsort.3 Normal file
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@@ -0,0 +1 @@
.so man3/radixsort.3