DataMuseum.dk

top - metrics - download

    Length: 23481 (0x5bb9)
    Types: TextFile
    Notes: UNIX file
    Names: »sort.c«

└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
    └─⟦f4b8d8c84⟧ UNIX Filesystem
        └─⟦this⟧ »cmd/sort.c« 

TextFile

/*
 * The sort command.
 * It does unique sorting, merges, and
 * ordinary sorts with zillions of
 * ways of specifying the sort keys.
 */

#include <stdio.h>
#include <ctype.h>
#include <mdata.h>
#include <signal.h>
#include <types.h>

#define	NREC	400		/* Longest key record */
#define	NSEL	20		/* Number of records in selection list */
#define	NPOS	20		/* Number of positionals */
#define	NTFILE	6		/* Number of intermediate files */
#define	MORDER		(NTFILE-1)	/* Order of polyphase merge */
#define	NDIST	(sizeof(dists)/sizeof(dists[0]))
#define	NCSET	(MAXUCHAR+1)	/* Size of char set */
#define	NSBRK	1024		/* Amount to add at a time */

#define	rfree(p) {p->r_next=frlist;frlist=p;}		/* Free a run */

/* Key ordering flags (global and field skips) */
#define	KBLANK	01		/* Ignore leading blanks */
#define	KDICT	02		/* Dictionary order (letters, digits, blanks) */
#define	KFOLD	04		/* Fold upper case onto lower case */
#define	KIGNORE	010		/* Ignore non-ascii characters */
#define	KNUM	020		/* Numeric sort - skip leading blanks */
#define	KREV	040		/* Reverse order of sort */

/*
 * Mapping table to speed up folding.
 * Initialised by `sortinit'.
 */
char	tabfold[NCSET];

/*
 * The temp file structure.  One for each file
 * contains the list-head for the runs and
 * the FILE stream pointer.
 */
typedef	struct	TFILE {
	struct	RUN	*tf_runs;
	FILE	*tf_fp;
	int	tf_nrun;
	size_t	tf_start;
}	TFILE;

TFILE	tfiles[NTFILE];

/*
 * The structure of each run.  contains
 * a pointer to the next and the start
 * and length of the run.
 */
typedef	struct	RUN {
	struct	RUN	*r_next;
	int	r_length;		/* Number of records in run */
}	RUN;

/*
 * Entries in positional (+m.n-m.n) parameters
 */
typedef	struct	POS {
	int	p_sflags;	/* Start flags */
	int	p_sm;		/* fields */
	int	p_sn;		/* chars */
	int	p_eflags;	/* End flags */
	int	p_em;		/* Ending fields */
	int	p_en;		/* Ending chars */
}	POS;

POS	pos[NPOS];
POS	*posp = &pos[-1];

/*
 * Numeric field breakout structure.
 */
typedef struct	NUM {
	int	n_sign;		/* Sign */
	int	n_magn;		/* Integer magnitude */
	int	n_fmagn;	/* Fractional magnitude */
	char	*n_bgn;		/* beginning */
	char	*n_end;		/* ending */
} NUM;

char	**flist;
char	*deflist[] = {
	"-", NULL
};

/*
 * This is the best distribution of runs for
 * the polyphase merge.  It is a sort of n-way
 * distribution of the Fibonacci number sequence.
 * Each level contains a total number of runs
 * and a way to subdivide them to this.  Dummy
 * runs are added to round out the initial distribution.
 * Each successive distribution vector (m0,m1,m2,m3,m4)
 * is obtained by cross product with this matrix:
 *	1 1 1 1 1
 *	1 0 0 0 0
 *	0 1 0 0 0
 *	0 0 1 0 0
 *	0 0 0 1 0
 * which can be generalised to any order of merge (other
 * than 5-way).
 * Also no more entries are given as this is
 * likely already overkill for sorting during
 * the lifetime of most machines.
 */
struct	dists {
	int	d_totruns;		/* Total of next 5 elements */
	int	d_runs[MORDER];	/* initial distribution */
}	dists[] = {
	1,	1, 0, 0, 0, 0,
	5,	1, 1, 1, 1, 1,
	9,	2, 2, 2, 2, 1,
	17,	4, 4, 4, 3, 2,
	33,	8, 8, 7, 6, 4,
	65,	16, 15, 14, 12, 8,
	129,	31, 30, 28, 24, 16,
	253,	61, 59, 55, 47, 31,
	497,	120, 116, 108, 92, 61,
	977,	236, 228, 212, 181, 120,
	1921,	464, 448, 417, 356, 236,
	3777,	912, 881, 820, 700, 464,
	7425,	1793, 1732, 1612, 1376, 912,
	14597,	3525, 3405, 3169, 2705, 1793,
	28697,	6930, 6694, 6230, 5318, 3525,
};

struct	dists	*savedsp;		/* Save current distribution level */

char	*outname;			/* Output other than stdout */
char	*tempdir;			/* Other than default temp directory */
char	template[100];
char	obuf[BUFSIZ];
char	ibuf[BUFSIZ];

/*
 * Structure for each input record
 * in natural selection.  First
 * an insertion sort fills the
 * tree and then all records
 * are input and output until
 * too many are out of order.
 */
typedef	struct	SEL {
	char	*s_inb;		/* Input buffer pointer */
	int	s_length;	/* Length of run in selection */
	FILE	*s_fp;		/* File pointer of run */
}	SEL;

RUN	*frlist;		/* Free run list */
SEL	sel[NSEL];
SEL	lastrec;
char	inbuf[NSEL+1][NREC];
#define	LASTREC	lastrec.s_inb	/* Buffer pointer of last written record */
char	temperr[] = "Temporary file open error";
char	tmpwerr[] = "Temporary file write error";
char	nomem[] = "Out of memory";
int	pid;				/* Current process ID */
char	tabc;				/* Tab character */
int	cflag;				/* Check ordering only */
int	mflag;				/* Merge only */
int	uflag;				/* Unique sort */
int	kflags;				/* Flags to control order to sort */

char	*sgets();
RUN	*copyfile();
RUN	*ralloc();
char	*alloc();
int	rmexit();
int	kcompar();
int	strcmp();
int	rstrcmp();
int	(*compar)() = kcompar;
char	*sprintf();

main(argc, argv)
int argc;
char *argv[];
{
	register char *ap;
	char dummyop[2];

	setbuf(stdin, ibuf);
	setbuf(stdout, obuf);
	setbuf(stderr, NULL);
	protect(SIGINT);
	protect(SIGHUP);
	protect(SIGPIPE);
	protect(SIGTERM);
	while (argc>1 && (*argv[1]=='-' || *argv[1]=='+')) {
		if (*argv[1] == '+') {
			readskip(argv[1]);
			argv++;
			argc--;
			if (argc>1 && argv[1][0]=='-' && isdigit(argv[1][1])) {
				readskip(argv[1]);
				argv++;
				argc--;
			}
			continue;
		}
		for (ap = &argv[1][1]; *ap != '\0'; ap++)
		switch (*ap) {

		/*
		 * Non-ordering options.
		 */
		case 'c':		/* Check ordering only */
			cflag = 1;
			break;

		case 'm':		/* Merge only */
			mflag = 1;
			break;

		case 'o':		/* Output other than stdout */
			if (outname != NULL)
				serr("Only one output name allowed");
			if (--argc < 2)
				usage();
			argv++;
			outname = argv[1];
			break;

		case 'T':		/* Alternative temp directory */
			if (tempdir != NULL)
				serr("Only one `-T' allowed");
			if (--argc < 2)
				usage();
			argv++;
			tempdir = argv[1];
			break;

		case 'u':		/* Unique sort */
			uflag = 1;
			break;

		/*
		 * Lexicographic ordering options.
		 */
		case 't':		/* Tab character */
			if ((tabc = *++ap) == '\0')
				usage();
			break;

		default:
			dummyop[0] = *ap;
			dummyop[1] = '\0';
			opts(dummyop, &kflags);
		}
		argc--;
		argv++;
	}
	if (argc > 1)
		flist = argv+1; else
		flist = deflist;
	sortinit();
	rmexit(sort());
}

/*
 * Initialise tables that speed up
 * special orderings.
 */
sortinit()
{
	register int c;
	register char *cp;

	cp = tabfold;
	for (c=0; c<NCSET; c++)
		*cp++ = (isascii(c) && isupper(c)) ? tolower(c) : c;
}

/*
 * Read in the ordering options into
 * the int that is referenced by `flagp'
 * from the string `s'.  Used both for
 * global options and with skip options.
 */
opts(s, flagp)
register char *s;
register int *flagp;
{
	*flagp = 0;
	while (*s)
		switch (*s++) {
		case 'b':
			*flagp |= KBLANK;
			break;

		case 'd':
			*flagp |= KDICT;
			break;

		case 'f':
			*flagp |= KFOLD;
			break;

		case 'i':
			*flagp |= KIGNORE;
			break;

		case 'n':
			*flagp |= KNUM;
			break;

		case 'r':
			*flagp |= KREV;
			break;

		default:
			usage();
		}
}

/*
 * Read in the skip (either the `+' or
 * the `-' kind).  Syntax check it and
 * store it away.
 */
readskip(s)
register char *s;
{
	register int n;
	register int plusskip = 0;

	plusskip = *s++ == '+';
	if (plusskip) {
		if (++posp >= &pos[NPOS])
			serr("Too many positional parameters");
		posp->p_em = MAXINT;
	}
	for (n=0; isdigit(*s); )
		n = n*10 + *s++ - '0';
	if (plusskip)
		posp->p_sm = n; else
		posp->p_em = n;
	if (*s == '.') {
		s++;
		for (n=0; isdigit(*s); )
			n = n*10 + *s++ - '0';
		if (plusskip)
			posp->p_sn = n; else
			posp->p_en = n;
	}
	opts(s, plusskip ? &posp->p_sflags : &posp->p_eflags);
}

/*
 * Actually figure out what kind of
 * sorting we have to do.
 */
sort()
{
	register FILE *fp;

	/*
	 * Optimisation for simple sorts
	 * to cut compare time down.
	 */
	if (posp<&pos[0] && (kflags&~KREV)==0) {
		if (kflags & KREV)
			compar = rstrcmp; else
			compar = strcmp;
	}
	if (cflag) {
		register char *b1, *b2;

		if (mflag || outname!=NULL || uflag)
			fprintf(stderr, "Checking only--some options ignored\n");
		b1 = NULL;
		b2 = inbuf[0];
		while (sgets(b2) != NULL) {
			if (b1 == NULL) {
				b2 = inbuf[1];
				b1 = inbuf[0];
				continue;
			}
			if ((*compar)(b1, b2) > 0) {
				fprintf(stderr, "sort: out of order at:\n");
				fprintf(stderr, "%s", b2);
				return (1);
			}
			if (b2 == inbuf[1]) {
				b1 = inbuf[1];
				b2 = inbuf[0];
			} else {
				b1 = inbuf[0];
				b2 = inbuf[1];
			}
		}
		return (0);
	}
	if (mflag) {
		if (copyruns())
			return (1);
	} else {
		if (selection())
			return (1);
	}
	dummyruns();
	if (merge())
		return (1);
	if (outname != NULL) {
		if (freopen(outname, "w", stdout) != stdout)
			serr("Cannot open output `%s'", outname);
	}
	fp = tfiles[MORDER].tf_fp;
	rewind(fp);
	LASTREC = NULL;
	while (fgets(inbuf[0], NREC, fp) != NULL) {
		if (uflag) {
			if (LASTREC == NULL)
				LASTREC = inbuf[1];
			else if ((*compar)(LASTREC, inbuf[0]) == 0)
				continue;
			strcpy(LASTREC, inbuf[0]);
		}
		fputs(inbuf[0], stdout);
	}
	fflush(stdout);
	if (ferror(stdout))
		serr("Write error on `%s'", outname==NULL ? "(stdout)":outname);
	fclose(fp);
	return (0);
}

/*
 * Copy the runs into the temp-files
 * for already-sorted but not merged data.
 */
copyruns()
{
	register char **flp = flist;
	register char *fn;
	register FILE *fp;
	register int s = 0;

	while ((fn = *flp++) != NULL) {
		if (fn[0]=='-' && fn[1]=='\0')
			fp = stdin;
		else if ((fp = fopen(fn, "r")) == NULL) {
			fprintf(stderr, "sort: cannot open `%s'\n", fn);
			s = 1;
			continue;
		}
		setbuf(fp, ibuf);
		if (copyfile(fp, nextrun()) == NULL)
			return (1);
		if (fp != stdin)
			fclose(fp);
	}
	return (s);
}

/*
 * Calculate the next run number to use,
 * based on the number that we already have.
 * The dummy runs go to the left (largest
 * number so they are used the most often)
 * Dummy runs are installed by another routine
 * after all runs are entered.
 */
nextrun()
{
	register struct dists *dsp;
	register int i;

	for (dsp = dists; dsp < &dists[NDIST]; dsp++) {
		for (i=MORDER-1; i>=0; i--) {
			if (tfiles[i].tf_nrun < dsp->d_runs[i]) {
				savedsp = dsp;
				return (i);
			}
		}
	}
	serr("Ridiculously many runs");
}

/*
 * Fill out the current distribution level
 * with dummy runs.
 */
dummyruns()
{
	register struct dists *dsp;
	register TFILE *tfp;
	register int i;

	dsp = savedsp;
	for (i=0; i<MORDER; i++)
		for (tfp = &tfiles[i]; tfp->tf_nrun < dsp->d_runs[i]; )
			tfp->tf_nrun++;
}

/*
 * Copy each run file to the appropriate temp file
 * given by the run number (`runno').
 * Also, check during the input for the file's
 * being sorted properly.
 * If `ifp' is NULL, this creates an empty
 * (distinguished from dummy) run.
 */
RUN *
copyfile(ifp, runno)
FILE *ifp;
int runno;
{
	register RUN *arp, *rp;
	register int c;
	register TFILE *tfp;
	register FILE *ofp;

	tfp = &tfiles[runno];
	tfp->tf_nrun++;
	if ((ofp = tfp->tf_fp) == NULL) {
		maketemp(runno);
		ofp = tfp->tf_fp;
	}
	arp = ralloc();
	arp->r_next = NULL;
	arp->r_length = 0;
	if (tfp->tf_runs == NULL)
		tfp->tf_runs = arp;
	else {
		for (rp = tfp->tf_runs; rp->r_next != NULL; rp = rp->r_next)
			;
		rp->r_next = arp;
	}
	if (ifp == NULL)
		return (arp);
	while ((c = getc(ifp)) != EOF) {
		if (c == '\n')
			arp->r_length++;
		putc(c, ofp);
	}
	fflush(ofp);
	if (ferror(ofp))
		serr(tmpwerr);
	return (arp);
}

/*
 * Use selection to create the initial runs.
 */
selection()
{
	register TFILE *tfp;
	register RUN *rp;
	register int i;
	register int nsel;

	for (;;) {
		for (i=0; i<NSEL; i++)
			sel[i].s_inb = inbuf[i];
		LASTREC = NULL;
		rp = copyfile(NULL, i = nextrun());
		tfp = &tfiles[i];
		for (nsel = 0; sgets(inbuf[nsel])!=NULL; ) {
			insert(nsel);
			if (++nsel >= NSEL)
				break;
		}
		for (i=0; i<nsel; i++) {
			if (uflag) {
				if (LASTREC != NULL)
					if ((*compar)(LASTREC, sel[i].s_inb)==0)
						continue;
				LASTREC = sel[i].s_inb;
			}
			fputs(sel[i].s_inb, tfp->tf_fp);
			rp->r_length++;
		}
		if (nsel < NSEL)
			break;
	}
	return (0);
}

/*
 * Insert the item at position `n'
 * into the sel table in sorted order.
 */
insert(n)
int n;
{
	register SEL *sp1, *sp2;
	register char *tmp;

	sp2 = &sel[n];
	for (sp1 = &sel[0]; sp1 < sp2; sp1++)
		if ((*compar)(sp1->s_inb, sp2->s_inb) > 0) {
			tmp = sp2->s_inb;
			for (; sp2 > sp1; sp2--)
				sp2->s_inb = (sp2-1)->s_inb;
			sp1->s_inb = tmp;
			break;
		}
}

/*
 * Merge the data
 * The algorithm is polyphase merge from
 * Knuth.
 */
merge()
{
	register int i, j;
	register int nr;
	TFILE temptf;

	nr = 0;
	j = 0;
	for (i=0; i<MORDER; i++)
		if (tfiles[i].tf_nrun) {
			j = i;
			nr += tfiles[i].tf_nrun;
		}
	if (nr <= 1) {
		tfiles[NTFILE-1] = tfiles[j];
		return (0);
	}
	for (i=0; i<NTFILE; i++)
		if (tfiles[i].tf_fp == NULL)
			maketemp(i);
	for (;;) {
		mergestep();
		nr = 0;
		for (i=0; i<MORDER; i++) {
			nr += tfiles[i].tf_nrun;
			if (tfiles[i].tf_nrun == 0)
				j = i;
		}
		if (nr <= 1)
			break;
		/*
		 * Exchange output and
		 * zeroed one so output
		 * is always in a fixed place.
		 */
		temptf = tfiles[MORDER];
		tfiles[MORDER] = tfiles[j];
		tfiles[j] = temptf;
	}
	return (0);
}

/*
 * Do one step of the polyphase merge.  The calling
 * routine has arranged that the output is
 * position MORDER and the inputs are the first
 * MORDER positions.
 */
mergestep()
{
	register int min;
	register int i;
	register RUN *rp;
	register FILE *ofp;
	register int len;
	register RUN *orp;

	rewind(tfiles[MORDER].tf_fp);
	tfiles[MORDER].tf_start = 0;
	min = tfiles[0].tf_nrun;
	fseek(tfiles[0].tf_fp, tfiles[0].tf_start, 0);
	for (i=1; i<MORDER; i++) {
		fseek(tfiles[i].tf_fp, tfiles[i].tf_start, 0);
		if (tfiles[i].tf_nrun < min)
			min = tfiles[i].tf_nrun;
	}
	while (min-- > 0) {
		orp = copyfile(NULL, MORDER);
		ofp = tfiles[MORDER].tf_fp;
		len = 0;
		for (i=0; i<MORDER; i++) {
			if ((rp = tfiles[i].tf_runs) != NULL) {
				tfiles[i].tf_runs = rp->r_next;
				len += rp->r_length;
				sel[i].s_length = rp->r_length;
				rfree(rp);
			} else
				sel[i].s_length = 0;
			tfiles[i].tf_nrun--;
			sel[i].s_inb = inbuf[i];
			sel[i].s_fp = tfiles[i].tf_fp;
		}
		orp->r_length = len;
		mergeread();
	}
	for (i=0; i<MORDER; i++)
		tfiles[i].tf_start = ftell(tfiles[i].tf_fp);
}

/*
 * Do the 5-way (MORDER) merge on one set
 * of runs which are described in the `sel'
 * struct array.
 */
mergeread()
{
	register SEL *sp;
	register SEL *minp;
	register int neof = 0;

	for (sp = sel; sp < &sel[MORDER]; sp++) {
		if (sp->s_length == 0) {
			neof++;
			sp->s_inb = NULL;
		} else {
			fgets(sp->s_inb, NREC, sp->s_fp);
			sp->s_length--;
		}
	}
	while (neof < MORDER) {
		minp = NULL;
		for (sp = sel; sp < &sel[MORDER]; sp++) {
			if (sp->s_inb == NULL)
				continue;
			if (minp == NULL) {
				minp = sp;
				continue;
			}
			if ((*compar)(sp->s_inb, minp->s_inb) <= 0)
				minp = sp;
		}
		fputs(minp->s_inb, tfiles[NTFILE-1].tf_fp);
		if (minp->s_length-- == 0) {
			minp->s_inb = NULL;
			neof++;
		} else
			fgets(minp->s_inb, NREC, minp->s_fp);
	}
}

/*
 * Get the next input character.  This
 * automatically goes from one file to the
 * next on EOF and only returns EOF at real
 * end of file.
 */
sgetc()
{
	static FILE *fp;
	register int c;

again:
	if (fp == NULL)
		if (*flist == NULL)
			return (EOF);
		else {
			if ((*flist)[0]=='-' && (*flist)[1]=='\0')
				fp = stdin;
			else if ((fp = fopen(*flist, "r")) == NULL)
				fprintf(stderr, "sort: cannot open %s\n", *flist);
			flist++;
			setbuf(fp, ibuf);
			goto again;
		}
	if ((c = getc(fp)) == EOF) {
		if (fp != stdin)
			fclose(fp);
		fp = NULL;
		goto again;
	}
	return (c);
}

/*
 * Get a string from sort input.  NULL on EOF, leave
 * trailing newlines on.
 */
char *
sgets(as)
char *as;
{
	register unsigned max = NREC;
	register int c;
	register char *s;

	s = as;
	while (--max>0 && (c = sgetc()) != EOF)
		if ((*s++ = c) == '\n')
			break;
	if (max == 0)
		serr("input record too long");
	*s = '\0';
	return (c==EOF && s==as ? NULL : as);
}

/*
 * Compare keys in strings `s1' and `s2'
 * taking into account all of the key selection
 * options and positional fields.
 * All comparison routines return -1 or <, 0 for equal,
 * and 1 for >.
 */
kcompar(s1, s2)
char *s1;
char *s2;
{
	char *fskip();
	register POS *pp;
	register char *ep1, *ep2;
	register int ret = 0;
	register char *p1, *p2;

	if (posp < &pos[0]) {
		for (ep1=s1; *ep1++ != '\0'; )
			;
		ep1--;
		for (ep2 = s2; *ep2++ != '\0'; )
			;
		ep2--;
		return (fcompar(s1, ep1, s2, ep2, kflags));
	}
	for (pp = &pos[0]; pp <= posp; pp++) {
		register int sflags, eflags;

		if ((sflags = pp->p_sflags) == 0)
			sflags = kflags;
		if ((eflags = pp->p_eflags) == 0)
			eflags = kflags;
		p1 = fskip(s1, pp->p_sm, pp->p_sn, sflags);
		p2 = fskip(s2, pp->p_sm, pp->p_sn, sflags);
		ep1 = fskip(s1, pp->p_em, pp->p_en, eflags);
		ep2 = fskip(s2, pp->p_em, pp->p_en, eflags);
		ret = fcompar(p1, ep1, p2, ep2, sflags|eflags);
		if (ret)
			break;
	}
	return (ret);
}

/*
 * Skip fields and space, returning the new pointer.
 * Arguments are `s' for string start, `m' and `n' from
 * the positional `m.n' format.
 * `f' is the flags - only `b' is
 * significant here.
 */
char *
fskip(s, m, n, f)
register char *s;
register int m;
register int n;
register int f;
{
	while (m--) {
		if (tabc) {
			while (*s!=tabc && *s!='\0')
				s++;
			if (*s != '\0')
				s++;
			else
				break;
		} else {
			while (*s==' ' || *s=='\t')
				s++;
			while (*s!=' ' && *s!='\t' && *s!='\0')
				s++;
			if (*s == '\0')
				break;
			if (m == 0)
				while (*s==' ' || *s=='\t')
					s++;
		}
	}
	if (f & KBLANK)
		while (*s==' ' || *s=='\t')
			s++;
	while (n--) {
		if (*s == '\0')
			break;
		s++;
	}
	return (s);
}

/*
 * Compare for the finally found field.
 * This takes into account all of the options
 * and the end and start of each string.
 */
fcompar(s1, e1, s2, e2, flags)
char *s1, *e1;
char *s2, *e2;
int flags;
{
	register char *p1, *p2;
	register int ret = 0;

	p1 = s1;
	p2 = s2;
	if (flags & (KBLANK|KNUM)) {
		while (*p1==' ' || *p1=='\t')
			p1++;
		while (*p2==' ' || *p2=='\t')
			p2++;
	}
	if (flags & KNUM) {
		NUM n1, n2;

		numpars(p1, e1, &n1);
		numpars(p2, e2, &n2);
		/* Compare integer magnitudes and signs */
		ret = n1.n_sign*n1.n_magn - n2.n_sign*n2.n_magn;
		if (ret != 0)
			ret = (ret < 0) ? -1 : 1;
		else {
			/* Compare integer parts */
			p1 = n1.n_bgn;
			p2 = n2.n_bgn;
			while (--n1.n_magn >= 0 && ret == 0)
				if (*p1 > *p2)
					ret = n1.n_sign;
				else if (*p1 < *p2)
					ret = - n1.n_sign;
				else {
					p1 += 1;
					p2 += 1;
				}
		}
		if (ret == 0)
			/* Compare fractional magnitudes and signs */
			ret = n1.n_sign*n1.n_fmagn - n2.n_sign*n2.n_fmagn;
		if (ret != 0)
			ret = ret < 0 ? -1 : 1;
		else {
			/* Compare fractional parts */
			e1 = n1.n_end;
			e2 = n2.n_end;
			while (p1 < e1 && p2 < e2 && ret == 0)
				if (*p1 > *p2)
					ret = n1.n_sign;
				else if (*p1 < *p2)
					ret = -n1.n_sign;
				else {
					p1 += 1;
					p2 += 1;
				}
		}
		if (ret == 0) {
			if (p1 < e1)
				ret = n1.n_sign;
			else
				ret = - n1.n_sign;
		}
	} else {
		register int c1, c2;

		if (flags & (KDICT|KIGNORE)) {
			for (;;) {
				for (; p1<e1; p1++) {
					if (flags&KIGNORE && !isprint(*p1))
						continue;
					if (flags & KDICT)
						if (!(isspace(*p1)
						    || isalnum(*p1)))
							continue;
					if (flags & KFOLD)
						c1 = tabfold[*p1++]; else
						c1 = *p1++;
					break;
				}
				for (; p2<e2; p2++) {
					if (flags&KIGNORE && !isprint(*p2))
						continue;
					if (flags & KDICT)
						if (!(isalnum(*p2)
						    || isspace(*p2)))
							continue;
					if (flags & KFOLD)
						c2 = tabfold[*p2++]; else
						c2 = *p2++;
					break;
				}
				if (p1>=e1 || p2>=e2)
					break;
				if (c1 != c2)
					break;
			}
		} else if (flags & KFOLD) {
			for (;;) {
				c1 = tabfold[*p1++];
				c2 = tabfold[*p2++];
				if (p1>=e1 || p2>=e2)
					break;
				if (c1 != c2)
					break;
			}
		} else {
			for (;;) {
				c1 = *p1++;
				c2 = *p2++;
				if (p1>=e1 || p2>=e2)
					break;
				if (c1 != c2)
					break;
			}
		}
		if (p1<=e1 && p2<=e2) {
			if (c1 < c2)
				ret--;
			else if (c1 > c2)
				ret++;
		} else if (p1 > e1) {
			ret++;
		} else
			ret --;
	}
	if (flags & KREV)
		return (-ret);
	return (ret);
}

/*
 * Parse a numeric field into sign, magnitude, integer and fractional parts.
 */
numpars(p, ep, np)
register char *p;
register char *ep;
register NUM *np;
{
	char *bp;
	char *fbgn;
	int fsum;

	bp = p;
	fbgn = NULL;
	fsum = 0;
	np->n_sign = 1;
	np->n_magn = 0;
	np->n_fmagn = 16000;
	np->n_bgn = NULL;
	for ( ; p < ep; p += 1)
		if (*p == '0') {
			if (fbgn != NULL) {
				if (fsum == 0)
					np->n_fmagn -= 1;
			} else if (np->n_magn != 0)
				np->n_magn += 1;
		} else if (isdigit(*p)) {
			if (fbgn != NULL)
				fsum += 1;
			else if (np->n_magn++ == 0)
				np->n_bgn = p;
		} else if (*p == '-') {
			if (p != bp)
				break;
			np->n_sign = -1;
		} else if (*p == '.') {
			if (fbgn != NULL || p+1 == ep)
				break;
			fbgn = p+1;
		} else {
			break;
		}
	np->n_end = p;
	if (fsum == 0) {
		np->n_fmagn = 0;
		fbgn = NULL;
	}
	if (np->n_bgn == NULL)
		np->n_bgn = fbgn;
	if (np->n_bgn == NULL)
		np->n_bgn = p;
}


/*
 * Reversed version of strcmp.  If this
 * were more common, it could be written
 * out in full to save the extra routine call.
 */
rstrcmp(s1, s2)
char *s1, *s2;
{
	return (-strcmp(s1, s2));
}

/*
 * Make temporary file `n'.
 * Called as they are first needed.
 */
maketemp(n)
{
	static int first = 1;
	char tempname[120];
	register FILE *fp;

	if (pid == 0) {
		pid = getpid();
		sprintf(template, "%s/sort%d%%c",
		    tempdir==NULL ? "/tmp" : tempdir, pid);
	}
	sprintf(tempname, template, n+'a');
	if ((fp = fopen(tempname, "w")) == NULL) {
		if (first && tempdir==NULL) {
			sprintf(template, "/usr/tmp/sort%d%%c", pid);
			sprintf(tempname, template, n+'a');
			if ((fp = fopen(tempname, "w")) == NULL)
				serr(temperr);
		} else
			serr(temperr);
	}
	fclose(fp);
	if ((tfiles[n].tf_fp = fopen(tempname, "r+w")) == NULL)
		serr(temperr);
	setbuf(tfiles[n].tf_fp, alloc(BUFSIZ));
	first = 0;
}

/* Errors and usage messages */
usage()
{
	fprintf(stderr, "Usage: sort [options] [+pos1 [-pos2]] ... [file ...]\n");
	fprintf(stderr, "Options: [-mubdfinr] [-tx] [-T directory] [-o name]\n");
	exit(1);
}

/* VARARGS */
serr(x)
{
	fprintf(stderr, "sort: %r\n", &x);
	rmexit(1);
}

/*
 * Exit, removing the tempfiles.
 */
rmexit(s)
int s;
{
	register int c;
	char tempname[120];

	for (c='a'; c<'a'+NTFILE; c++)
		unlink(sprintf(tempname, template, c));
	_exit(s);
}

/*
 * Protect from the specified signal number.
 * This makes that signal call the cleanup
 * routine, unless that signal was already ignored.
 */
protect(signo)
register int signo;
{
	if (signal(signo, SIG_IGN) != SIG_IGN)
		signal(signo, rmexit);
}

/*
 * Allocate a new run.  Uses our own threaded free list
 * and sbrk-style alloc when none of these.
 */
RUN *
ralloc()
{
	register RUN *p;

	if ((p = frlist) != NULL) {
		frlist = p->r_next;
		return (p);
	}
	return ((RUN *)alloc(sizeof (RUN)));
}

/*
 * This allocator simply does sbrk calls so that
 * it can grow (easily) the space as it needs without
 * threading it.  It also checks and prints an error
 * if out of space.
 */
char *
alloc(nb)
register unsigned nb;
{
	static int *rp, *ep;
	register int *cp;

	if ((nb = (nb+sizeof(int)-1)/sizeof(int)) == 0)
		serr(nomem);
	if (rp==NULL || rp+nb>=ep) {
		if ((ep = (int *)sbrk(NSBRK)) == NULL)
			serr(nomem);
		if (rp == NULL)
			rp = ep;
		ep += NSBRK/sizeof(int);
	}
	cp = rp;
	rp += nb;
	return (cp);
}