Add new radixsort and sradixsort functions

Taken from FreeBSD.

6 files changed, 497 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 315ad97..ad73456 100644
--- a/Makefile
+++ b/Makefile
@@ -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 \
diff --git a/Versions b/Versions
index cac2efe..51dc9ec 100644
--- a/Versions
+++ b/Versions
@@ -70,5 +70,7 @@ LIBBSD_0.3 {
     getpeereid;
 
     mergesort;
+    radixsort;
+    sradixsort;
 } LIBBSD_0.2;
 
diff --git a/include/bsd/stdlib.h b/include/bsd/stdlib.h
index bfe3027..ea790bc 100644
--- a/include/bsd/stdlib.h
+++ b/include/bsd/stdlib.h
@@ -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);
 
diff --git a/src/radixsort.3 b/src/radixsort.3
new file mode 100644
index 0000000..dfa65f1
--- /dev/null
+++ b/src/radixsort.3
@@ -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 .
diff --git a/src/radixsort.c b/src/radixsort.c
new file mode 100644
index 0000000..82ff1bc
--- /dev/null
+++ b/src/radixsort.c
@@ -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);
+		}
+}
diff --git a/src/sradixsort.3 b/src/sradixsort.3
new file mode 100644
index 0000000..86a95a3
--- /dev/null
+++ b/src/sradixsort.3
@@ -0,0 +1 @@
+.so man3/radixsort.3