contrib/awk/run.c

/****************************************************************
Copyright (C) Lucent Technologies 1997
All Rights Reserved

Permission to use, copy, modify, and distribute this software and
its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the name Lucent Technologies or any of
its entities not be used in advertising or publicity pertaining
to distribution of the software without specific, written prior
permission.

LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.
****************************************************************/

#define DEBUG
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <wchar.h>
#include <wctype.h>
#include <fcntl.h>
#include <setjmp.h>
#include <limits.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "awk.h"
#include "awkgram.tab.h"

static void stdinit(void);
static void flush_all(void);

#if 1
#define tempfree(x)	do { if (istemp(x)) tfree(x); } while (/*CONSTCOND*/0)
#else
void tempfree(Cell *p) {
	if (p->ctype == OCELL && (p->csub < CUNK || p->csub > CFREE)) {
		WARNING("bad csub %d in Cell %d %s",
			p->csub, p->ctype, p->sval);
	}
	if (istemp(p))
		tfree(p);
}
#endif

/* do we really need these? */
/* #ifdef _NFILE */
/* #ifndef FOPEN_MAX */
/* #define FOPEN_MAX _NFILE */
/* #endif */
/* #endif */
/*  */
/* #ifndef	FOPEN_MAX */
/* #define	FOPEN_MAX	40 */	/* max number of open files */
/* #endif */
/*  */
/* #ifndef RAND_MAX */
/* #define RAND_MAX	32767 */	/* all that ansi guarantees */
/* #endif */

jmp_buf env;
extern	int	pairstack[];
extern	Awkfloat	srand_seed;

Node	*winner = NULL;	/* root of parse tree */
Cell	*tmps;		/* free temporary cells for execution */

static Cell	truecell	={ OBOOL, BTRUE, 0, 0, 1.0, NUM, NULL, NULL };
Cell	*True	= &truecell;
static Cell	falsecell	={ OBOOL, BFALSE, 0, 0, 0.0, NUM, NULL, NULL };
Cell	*False	= &falsecell;
static Cell	breakcell	={ OJUMP, JBREAK, 0, 0, 0.0, NUM, NULL, NULL };
Cell	*jbreak	= &breakcell;
static Cell	contcell	={ OJUMP, JCONT, 0, 0, 0.0, NUM, NULL, NULL };
Cell	*jcont	= &contcell;
static Cell	nextcell	={ OJUMP, JNEXT, 0, 0, 0.0, NUM, NULL, NULL };
Cell	*jnext	= &nextcell;
static Cell	nextfilecell	={ OJUMP, JNEXTFILE, 0, 0, 0.0, NUM, NULL, NULL };
Cell	*jnextfile	= &nextfilecell;
static Cell	exitcell	={ OJUMP, JEXIT, 0, 0, 0.0, NUM, NULL, NULL };
Cell	*jexit	= &exitcell;
static Cell	retcell		={ OJUMP, JRET, 0, 0, 0.0, NUM, NULL, NULL };
Cell	*jret	= &retcell;
static Cell	tempcell	={ OCELL, CTEMP, 0, EMPTY, 0.0, NUM|STR|DONTFREE, NULL, NULL };

Node	*curnode = NULL;	/* the node being executed, for debugging */

/* buffer memory management */
int adjbuf(char **pbuf, int *psiz, int minlen, int quantum, char **pbptr,
	const char *whatrtn)
/* pbuf:    address of pointer to buffer being managed
 * psiz:    address of buffer size variable
 * minlen:  minimum length of buffer needed
 * quantum: buffer size quantum
 * pbptr:   address of movable pointer into buffer, or 0 if none
 * whatrtn: name of the calling routine if failure should cause fatal error
 *
 * return   0 for realloc failure, !=0 for success
 */
{
	if (minlen > *psiz) {
		char *tbuf;
		int rminlen = quantum ? minlen % quantum : 0;
		int boff = pbptr ? *pbptr - *pbuf : 0;
		/* round up to next multiple of quantum */
		if (rminlen)
			minlen += quantum - rminlen;
		tbuf = (char *) realloc(*pbuf, minlen);
		DPRINTF("adjbuf %s: %d %d (pbuf=%p, tbuf=%p)\n", whatrtn, *psiz, minlen, (void*)*pbuf, (void*)tbuf);
		if (tbuf == NULL) {
			if (whatrtn)
				FATAL("out of memory in %s", whatrtn);
			return 0;
		}
		*pbuf = tbuf;
		*psiz = minlen;
		if (pbptr)
			*pbptr = tbuf + boff;
	}
	return 1;
}

void run(Node *a)	/* execution of parse tree starts here */
{

	stdinit();
	execute(a);
	closeall();
}

Cell *execute(Node *u)	/* execute a node of the parse tree */
{
	Cell *(*proc)(Node **, int);
	Cell *x;
	Node *a;

	if (u == NULL)
		return(True);
	for (a = u; ; a = a->nnext) {
		curnode = a;
		if (isvalue(a)) {
			x = (Cell *) (a->narg[0]);
			if (isfld(x) && !donefld)
				fldbld();
			else if (isrec(x) && !donerec)
				recbld();
			return(x);
		}
		if (notlegal(a->nobj))	/* probably a Cell* but too risky to print */
			FATAL("illegal statement");
		proc = proctab[a->nobj-FIRSTTOKEN];
		x = (*proc)(a->narg, a->nobj);
		if (isfld(x) && !donefld)
			fldbld();
		else if (isrec(x) && !donerec)
			recbld();
		if (isexpr(a))
			return(x);
		if (isjump(x))
			return(x);
		if (a->nnext == NULL)
			return(x);
		tempfree(x);
	}
}


Cell *program(Node **a, int n)	/* execute an awk program */
{				/* a[0] = BEGIN, a[1] = body, a[2] = END */
	Cell *x;

	if (setjmp(env) != 0)
		goto ex;
	if (a[0]) {		/* BEGIN */
		x = execute(a[0]);
		if (isexit(x))
			return(True);
		if (isjump(x))
			FATAL("illegal break, continue, next or nextfile from BEGIN");
		tempfree(x);
	}
	if (a[1] || a[2])
		while (getrec(&record, &recsize, true) > 0) {
			x = execute(a[1]);
			if (isexit(x))
				break;
			tempfree(x);
		}
  ex:
	if (setjmp(env) != 0)	/* handles exit within END */
		goto ex1;
	if (a[2]) {		/* END */
		x = execute(a[2]);
		if (isbreak(x) || isnext(x) || iscont(x))
			FATAL("illegal break, continue, next or nextfile from END");
		tempfree(x);
	}
  ex1:
	return(True);
}

struct Frame {	/* stack frame for awk function calls */
	int nargs;	/* number of arguments in this call */
	Cell *fcncell;	/* pointer to Cell for function */
	Cell **args;	/* pointer to array of arguments after execute */
	Cell *retval;	/* return value */
};

#define	NARGS	50	/* max args in a call */

struct Frame *frame = NULL;	/* base of stack frames; dynamically allocated */
int	nframe = 0;		/* number of frames allocated */
struct Frame *frp = NULL;	/* frame pointer. bottom level unused */

Cell *call(Node **a, int n)	/* function call.  very kludgy and fragile */
{
	static const Cell newcopycell = { OCELL, CCOPY, 0, EMPTY, 0.0, NUM|STR|DONTFREE, NULL, NULL };
	int i, ncall, ndef;
	int freed = 0; /* handles potential double freeing when fcn & param share a tempcell */
	Node *x;
	Cell *args[NARGS], *oargs[NARGS];	/* BUG: fixed size arrays */
	Cell *y, *z, *fcn;
	char *s;

	fcn = execute(a[0]);	/* the function itself */
	s = fcn->nval;
	if (!isfcn(fcn))
		FATAL("calling undefined function %s", s);
	if (frame == NULL) {
		frp = frame = (struct Frame *) calloc(nframe += 100, sizeof(*frame));
		if (frame == NULL)
			FATAL("out of space for stack frames calling %s", s);
	}
	for (ncall = 0, x = a[1]; x != NULL; x = x->nnext)	/* args in call */
		ncall++;
	ndef = (int) fcn->fval;			/* args in defn */
	DPRINTF("calling %s, %d args (%d in defn), frp=%d\n", s, ncall, ndef, (int) (frp-frame));
	if (ncall > ndef)
		WARNING("function %s called with %d args, uses only %d",
			s, ncall, ndef);
	if (ncall + ndef > NARGS)
		FATAL("function %s has %d arguments, limit %d", s, ncall+ndef, NARGS);
	for (i = 0, x = a[1]; x != NULL; i++, x = x->nnext) {	/* get call args */
		DPRINTF("evaluate args[%d], frp=%d:\n", i, (int) (frp-frame));
		y = execute(x);
		oargs[i] = y;
		DPRINTF("args[%d]: %s %f <%s>, t=%o\n",
			i, NN(y->nval), y->fval, isarr(y) ? "(array)" : NN(y->sval), y->tval);
		if (isfcn(y))
			FATAL("can't use function %s as argument in %s", y->nval, s);
		if (isarr(y))
			args[i] = y;	/* arrays by ref */
		else
			args[i] = copycell(y);
		tempfree(y);
	}
	for ( ; i < ndef; i++) {	/* add null args for ones not provided */
		args[i] = gettemp();
		*args[i] = newcopycell;
	}
	frp++;	/* now ok to up frame */
	if (frp >= frame + nframe) {
		int dfp = frp - frame;	/* old index */
		frame = (struct Frame *) realloc(frame, (nframe += 100) * sizeof(*frame));
		if (frame == NULL)
			FATAL("out of space for stack frames in %s", s);
		frp = frame + dfp;
	}
	frp->fcncell = fcn;
	frp->args = args;
	frp->nargs = ndef;	/* number defined with (excess are locals) */
	frp->retval = gettemp();

	DPRINTF("start exec of %s, frp=%d\n", s, (int) (frp-frame));
	y = execute((Node *)(fcn->sval));	/* execute body */
	DPRINTF("finished exec of %s, frp=%d\n", s, (int) (frp-frame));

	for (i = 0; i < ndef; i++) {
		Cell *t = frp->args[i];
		if (isarr(t)) {
			if (t->csub == CCOPY) {
				if (i >= ncall) {
					freesymtab(t);
					t->csub = CTEMP;
					tempfree(t);
				} else {
					oargs[i]->tval = t->tval;
					oargs[i]->tval &= ~(STR|NUM|DONTFREE);
					oargs[i]->sval = t->sval;
					tempfree(t);
				}
			}
		} else if (t != y) {	/* kludge to prevent freeing twice */
			t->csub = CTEMP;
			tempfree(t);
		} else if (t == y && t->csub == CCOPY) {
			t->csub = CTEMP;
			tempfree(t);
			freed = 1;
		}
	}
	tempfree(fcn);
	if (isexit(y) || isnext(y))
		return y;
	if (freed == 0) {
		tempfree(y);	/* don't free twice! */
	}
	z = frp->retval;			/* return value */
	DPRINTF("%s returns %g |%s| %o\n", s, getfval(z), getsval(z), z->tval);
	frp--;
	return(z);
}

Cell *copycell(Cell *x)	/* make a copy of a cell in a temp */
{
	Cell *y;

	/* copy is not constant or field */

	y = gettemp();
	y->tval = x->tval & ~(CON|FLD|REC);
	y->csub = CCOPY;	/* prevents freeing until call is over */
	y->nval = x->nval;	/* BUG? */
	if (isstr(x) /* || x->ctype == OCELL */) {
		y->sval = tostring(x->sval);
		y->tval &= ~DONTFREE;
	} else
		y->tval |= DONTFREE;
	y->fval = x->fval;
	return y;
}

Cell *arg(Node **a, int n)	/* nth argument of a function */
{

	n = ptoi(a[0]);	/* argument number, counting from 0 */
	DPRINTF("arg(%d), frp->nargs=%d\n", n, frp->nargs);
	if (n+1 > frp->nargs)
		FATAL("argument #%d of function %s was not supplied",
			n+1, frp->fcncell->nval);
	return frp->args[n];
}

Cell *jump(Node **a, int n)	/* break, continue, next, nextfile, return */
{
	Cell *y;

	switch (n) {
	case EXIT:
		if (a[0] != NULL) {
			y = execute(a[0]);
			errorflag = (int) getfval(y);
			tempfree(y);
		}
		longjmp(env, 1);
	case RETURN:
		if (a[0] != NULL) {
			y = execute(a[0]);
			if ((y->tval & (STR|NUM)) == (STR|NUM)) {
				setsval(frp->retval, getsval(y));
				frp->retval->fval = getfval(y);
				frp->retval->tval |= NUM;
			}
			else if (y->tval & STR)
				setsval(frp->retval, getsval(y));
			else if (y->tval & NUM)
				setfval(frp->retval, getfval(y));
			else		/* can't happen */
				FATAL("bad type variable %d", y->tval);
			tempfree(y);
		}
		return(jret);
	case NEXT:
		return(jnext);
	case NEXTFILE:
		nextfile();
		return(jnextfile);
	case BREAK:
		return(jbreak);
	case CONTINUE:
		return(jcont);
	default:	/* can't happen */
		FATAL("illegal jump type %d", n);
	}
	return 0;	/* not reached */
}

Cell *awkgetline(Node **a, int n)	/* get next line from specific input */
{		/* a[0] is variable, a[1] is operator, a[2] is filename */
	Cell *r, *x;
	extern Cell **fldtab;
	FILE *fp;
	char *buf;
	int bufsize = recsize;
	int mode;
	bool newflag;
	double result;

	if ((buf = (char *) malloc(bufsize)) == NULL)
		FATAL("out of memory in getline");

	fflush(stdout);	/* in case someone is waiting for a prompt */
	r = gettemp();
	if (a[1] != NULL) {		/* getline < file */
		x = execute(a[2]);		/* filename */
		mode = ptoi(a[1]);
		if (mode == '|')		/* input pipe */
			mode = LE;	/* arbitrary flag */
		fp = openfile(mode, getsval(x), &newflag);
		tempfree(x);
		if (fp == NULL)
			n = -1;
		else
			n = readrec(&buf, &bufsize, fp, newflag);
		if (n <= 0) {
			;
		} else if (a[0] != NULL) {	/* getline var <file */
			x = execute(a[0]);
			setsval(x, buf);
			if (is_number(x->sval, & result)) {
				x->fval = result;
				x->tval |= NUM;
			}
			tempfree(x);
		} else {			/* getline <file */
			setsval(fldtab[0], buf);
			if (is_number(fldtab[0]->sval, & result)) {
				fldtab[0]->fval = result;
				fldtab[0]->tval |= NUM;
			}
		}
	} else {			/* bare getline; use current input */
		if (a[0] == NULL)	/* getline */
			n = getrec(&record, &recsize, true);
		else {			/* getline var */
			n = getrec(&buf, &bufsize, false);
			if (n > 0) {
				x = execute(a[0]);
				setsval(x, buf);
				if (is_number(x->sval, & result)) {
					x->fval = result;
					x->tval |= NUM;
				}
				tempfree(x);
			}
		}
	}
	setfval(r, (Awkfloat) n);
	free(buf);
	return r;
}

Cell *getnf(Node **a, int n)	/* get NF */
{
	if (!donefld)
		fldbld();
	return (Cell *) a[0];
}

static char *
makearraystring(Node *p, const char *func)
{
	char *buf;
	int bufsz = recsize;
	size_t blen;

	if ((buf = (char *) malloc(bufsz)) == NULL) {
		FATAL("%s: out of memory", func);
	}

	blen = 0;
	buf[blen] = '\0';

	for (; p; p = p->nnext) {
		Cell *x = execute(p);	/* expr */
		char *s = getsval(x);
		size_t seplen = strlen(getsval(subseploc));
		size_t nsub = p->nnext ? seplen : 0;
		size_t slen = strlen(s);
		size_t tlen = blen + slen + nsub;

		if (!adjbuf(&buf, &bufsz, tlen + 1, recsize, 0, func)) {
			FATAL("%s: out of memory %s[%s...]",
			    func, x->nval, buf);
		}
		memcpy(buf + blen, s, slen);
		if (nsub) {
			memcpy(buf + blen + slen, *SUBSEP, nsub);
		}
		buf[tlen] = '\0';
		blen = tlen;
		tempfree(x);
	}
	return buf;
}

Cell *array(Node **a, int n)	/* a[0] is symtab, a[1] is list of subscripts */
{
	Cell *x, *z;
	char *buf;

	x = execute(a[0]);	/* Cell* for symbol table */
	buf = makearraystring(a[1], __func__);
	if (!isarr(x)) {
		DPRINTF("making %s into an array\n", NN(x->nval));
		if (freeable(x))
			xfree(x->sval);
		x->tval &= ~(STR|NUM|DONTFREE);
		x->tval |= ARR;
		x->sval = (char *) makesymtab(NSYMTAB);
	}
	z = setsymtab(buf, "", 0.0, STR|NUM, (Array *) x->sval);
	z->ctype = OCELL;
	z->csub = CVAR;
	tempfree(x);
	free(buf);
	return(z);
}

Cell *awkdelete(Node **a, int n)	/* a[0] is symtab, a[1] is list of subscripts */
{
	Cell *x;

	x = execute(a[0]);	/* Cell* for symbol table */
	if (x == symtabloc) {
		FATAL("cannot delete SYMTAB or its elements");
	}
	if (!isarr(x))
		return True;
	if (a[1] == NULL) {	/* delete the elements, not the table */
		freesymtab(x);
		x->tval &= ~STR;
		x->tval |= ARR;
		x->sval = (char *) makesymtab(NSYMTAB);
	} else {
		char *buf = makearraystring(a[1], __func__);
		freeelem(x, buf);
		free(buf);
	}
	tempfree(x);
	return True;
}

Cell *intest(Node **a, int n)	/* a[0] is index (list), a[1] is symtab */
{
	Cell *ap, *k;
	char *buf;

	ap = execute(a[1]);	/* array name */
	if (!isarr(ap)) {
		DPRINTF("making %s into an array\n", ap->nval);
		if (freeable(ap))
			xfree(ap->sval);
		ap->tval &= ~(STR|NUM|DONTFREE);
		ap->tval |= ARR;
		ap->sval = (char *) makesymtab(NSYMTAB);
	}
	buf = makearraystring(a[0], __func__);
	k = lookup(buf, (Array *) ap->sval);
	tempfree(ap);
	free(buf);
	if (k == NULL)
		return(False);
	else
		return(True);
}


Cell *matchop(Node **a, int n)	/* ~ and match() */
{
	Cell *x, *y;
	char *s, *t;
	int i;
	fa *pfa;
	int (*mf)(fa *, const char *) = match, mode = 0;

	if (n == MATCHFCN) {
		mf = pmatch;
		mode = 1;
	}
	x = execute(a[1]);	/* a[1] = target text */
	s = getsval(x);
	if (a[0] == NULL)	/* a[1] == 0: already-compiled reg expr */
		i = (*mf)((fa *) a[2], s);
	else {
		y = execute(a[2]);	/* a[2] = regular expr */
		t = getsval(y);
		pfa = makedfa(t, mode);
		i = (*mf)(pfa, s);
		tempfree(y);
	}
	tempfree(x);
	if (n == MATCHFCN) {
		int start = patbeg - s + 1;
		if (patlen < 0)
			start = 0;
		setfval(rstartloc, (Awkfloat) start);
		setfval(rlengthloc, (Awkfloat) patlen);
		x = gettemp();
		x->tval = NUM;
		x->fval = start;
		return x;
	} else if ((n == MATCH && i == 1) || (n == NOTMATCH && i == 0))
		return(True);
	else
		return(False);
}


Cell *boolop(Node **a, int n)	/* a[0] || a[1], a[0] && a[1], !a[0] */
{
	Cell *x, *y;
	int i;

	x = execute(a[0]);
	i = istrue(x);
	tempfree(x);
	switch (n) {
	case BOR:
		if (i) return(True);
		y = execute(a[1]);
		i = istrue(y);
		tempfree(y);
		if (i) return(True);
		else return(False);
	case AND:
		if ( !i ) return(False);
		y = execute(a[1]);
		i = istrue(y);
		tempfree(y);
		if (i) return(True);
		else return(False);
	case NOT:
		if (i) return(False);
		else return(True);
	default:	/* can't happen */
		FATAL("unknown boolean operator %d", n);
	}
	return 0;	/*NOTREACHED*/
}

Cell *relop(Node **a, int n)	/* a[0 < a[1], etc. */
{
	int i;
	Cell *x, *y;
	Awkfloat j;

	x = execute(a[0]);
	y = execute(a[1]);
	if (x->tval&NUM && y->tval&NUM) {
		j = x->fval - y->fval;
		i = j<0? -1: (j>0? 1: 0);
	} else {
		i = strcmp(getsval(x), getsval(y));
	}
	tempfree(x);
	tempfree(y);
	switch (n) {
	case LT:	if (i<0) return(True);
			else return(False);
	case LE:	if (i<=0) return(True);
			else return(False);
	case NE:	if (i!=0) return(True);
			else return(False);
	case EQ:	if (i == 0) return(True);
			else return(False);
	case GE:	if (i>=0) return(True);
			else return(False);
	case GT:	if (i>0) return(True);
			else return(False);
	default:	/* can't happen */
		FATAL("unknown relational operator %d", n);
	}
	return 0;	/*NOTREACHED*/
}

void tfree(Cell *a)	/* free a tempcell */
{
	if (freeable(a)) {
		DPRINTF("freeing %s %s %o\n", NN(a->nval), NN(a->sval), a->tval);
		xfree(a->sval);
	}
	if (a == tmps)
		FATAL("tempcell list is curdled");
	a->cnext = tmps;
	tmps = a;
}

Cell *gettemp(void)	/* get a tempcell */
{	int i;
	Cell *x;

	if (!tmps) {
		tmps = (Cell *) calloc(100, sizeof(*tmps));
		if (!tmps)
			FATAL("out of space for temporaries");
		for (i = 1; i < 100; i++)
			tmps[i-1].cnext = &tmps[i];
		tmps[i-1].cnext = NULL;
	}
	x = tmps;
	tmps = x->cnext;
	*x = tempcell;
	return(x);
}

Cell *indirect(Node **a, int n)	/* $( a[0] ) */
{
	Awkfloat val;
	Cell *x;
	int m;
	char *s;

	x = execute(a[0]);
	val = getfval(x);	/* freebsd: defend against super large field numbers */
	if ((Awkfloat)INT_MAX < val)
		FATAL("trying to access out of range field %s", x->nval);
	m = (int) val;
	if (m == 0 && !is_number(s = getsval(x), NULL))	/* suspicion! */
		FATAL("illegal field $(%s), name \"%s\"", s, x->nval);
		/* BUG: can x->nval ever be null??? */
	tempfree(x);
	x = fieldadr(m);
	x->ctype = OCELL;	/* BUG?  why are these needed? */
	x->csub = CFLD;
	return(x);
}

Cell *substr(Node **a, int nnn)		/* substr(a[0], a[1], a[2]) */
{
	int k, m, n;
	char *s;
	int temp;
	Cell *x, *y, *z = NULL;

	x = execute(a[0]);
	y = execute(a[1]);
	if (a[2] != NULL)
		z = execute(a[2]);
	s = getsval(x);
	k = strlen(s) + 1;
	if (k <= 1) {
		tempfree(x);
		tempfree(y);
		if (a[2] != NULL) {
			tempfree(z);
		}
		x = gettemp();
		setsval(x, "");
		return(x);
	}
	m = (int) getfval(y);
	if (m <= 0)
		m = 1;
	else if (m > k)
		m = k;
	tempfree(y);
	if (a[2] != NULL) {
		n = (int) getfval(z);
		tempfree(z);
	} else
		n = k - 1;
	if (n < 0)
		n = 0;
	else if (n > k - m)
		n = k - m;
	DPRINTF("substr: m=%d, n=%d, s=%s\n", m, n, s);
	y = gettemp();
	temp = s[n+m-1];	/* with thanks to John Linderman */
	s[n+m-1] = '\0';
	setsval(y, s + m - 1);
	s[n+m-1] = temp;
	tempfree(x);
	return(y);
}

Cell *sindex(Node **a, int nnn)		/* index(a[0], a[1]) */
{
	Cell *x, *y, *z;
	char *s1, *s2, *p1, *p2, *q;
	Awkfloat v = 0.0;

	x = execute(a[0]);
	s1 = getsval(x);
	y = execute(a[1]);
	s2 = getsval(y);

	z = gettemp();
	for (p1 = s1; *p1 != '\0'; p1++) {
		for (q = p1, p2 = s2; *p2 != '\0' && *q == *p2; q++, p2++)
			continue;
		if (*p2 == '\0') {
			v = (Awkfloat) (p1 - s1 + 1);	/* origin 1 */
			break;
		}
	}
	tempfree(x);
	tempfree(y);
	setfval(z, v);
	return(z);
}

#define	MAXNUMSIZE	50

int format(char **pbuf, int *pbufsize, const char *s, Node *a)	/* printf-like conversions */
{
	char *fmt;
	char *p, *t;
	const char *os;
	Cell *x;
	int flag = 0, n;
	int fmtwd; /* format width */
	int fmtsz = recsize;
	char *buf = *pbuf;
	int bufsize = *pbufsize;
#define FMTSZ(a)   (fmtsz - ((a) - fmt))
#define BUFSZ(a)   (bufsize - ((a) - buf))

	static bool first = true;
	static bool have_a_format = false;

	if (first) {
		char xbuf[100];

		snprintf(xbuf, sizeof(xbuf), "%a", 42.0);
		have_a_format = (strcmp(xbuf, "0x1.5p+5") == 0);
		first = false;
	}

	os = s;
	p = buf;
	if ((fmt = (char *) malloc(fmtsz)) == NULL)
		FATAL("out of memory in format()");
	while (*s) {
		adjbuf(&buf, &bufsize, MAXNUMSIZE+1+p-buf, recsize, &p, "format1");
		if (*s != '%') {
			*p++ = *s++;
			continue;
		}
		if (*(s+1) == '%') {
			*p++ = '%';
			s += 2;
			continue;
		}
		/* have to be real careful in case this is a huge number, eg, %100000d */
		fmtwd = atoi(s+1);
		if (fmtwd < 0)
			fmtwd = -fmtwd;
		adjbuf(&buf, &bufsize, fmtwd+1+p-buf, recsize, &p, "format2");
		for (t = fmt; (*t++ = *s) != '\0'; s++) {
			if (!adjbuf(&fmt, &fmtsz, MAXNUMSIZE+1+t-fmt, recsize, &t, "format3"))
				FATAL("format item %.30s... ran format() out of memory", os);
			/* Ignore size specifiers */
			if (strchr("hjLlqtz", *s) != NULL) {	/* the ansi panoply */
				t--;
				continue;
			}
			if (isalpha((uschar)*s))
				break;
			if (*s == '$') {
				FATAL("'$' not permitted in awk formats");
			}
			if (*s == '*') {
				if (a == NULL) {
					FATAL("not enough args in printf(%s)", os);
				}
				x = execute(a);
				a = a->nnext;
				snprintf(t - 1, FMTSZ(t - 1),
				    "%d", fmtwd=(int) getfval(x));
				if (fmtwd < 0)
					fmtwd = -fmtwd;
				adjbuf(&buf, &bufsize, fmtwd+1+p-buf, recsize, &p, "format");
				t = fmt + strlen(fmt);
				tempfree(x);
			}
		}
		*t = '\0';
		if (fmtwd < 0)
			fmtwd = -fmtwd;
		adjbuf(&buf, &bufsize, fmtwd+1+p-buf, recsize, &p, "format4");
		switch (*s) {
		case 'a': case 'A':
			if (have_a_format)
				flag = *s;
			else
				flag = 'f';
			break;
		case 'f': case 'e': case 'g': case 'E': case 'G':
			flag = 'f';
			break;
		case 'd': case 'i': case 'o': case 'x': case 'X': case 'u':
			flag = (*s == 'd' || *s == 'i') ? 'd' : 'u';
			*(t-1) = 'j';
			*t = *s;
			*++t = '\0';
			break;
		case 's':
			flag = 's';
			break;
		case 'c':
			flag = 'c';
			break;
		default:
			WARNING("weird printf conversion %s", fmt);
			flag = '?';
			break;
		}
		if (a == NULL)
			FATAL("not enough args in printf(%s)", os);
		x = execute(a);
		a = a->nnext;
		n = MAXNUMSIZE;
		if (fmtwd > n)
			n = fmtwd;
		adjbuf(&buf, &bufsize, 1+n+p-buf, recsize, &p, "format5");
		switch (flag) {
		case '?':	snprintf(p, BUFSZ(p), "%s", fmt);	/* unknown, so dump it too */
			t = getsval(x);
			n = strlen(t);
			if (fmtwd > n)
				n = fmtwd;
			adjbuf(&buf, &bufsize, 1+strlen(p)+n+p-buf, recsize, &p, "format6");
			p += strlen(p);
			snprintf(p, BUFSZ(p), "%s", t);
			break;
		case 'a':
		case 'A':
		case 'f':	snprintf(p, BUFSZ(p), fmt, getfval(x)); break;
		case 'd':	snprintf(p, BUFSZ(p), fmt, (intmax_t) getfval(x)); break;
		case 'u':	snprintf(p, BUFSZ(p), fmt, (uintmax_t) getfval(x)); break;
		case 's':
			t = getsval(x);
			n = strlen(t);
			if (fmtwd > n)
				n = fmtwd;
			if (!adjbuf(&buf, &bufsize, 1+n+p-buf, recsize, &p, "format7"))
				FATAL("huge string/format (%d chars) in printf %.30s... ran format() out of memory", n, t);
			snprintf(p, BUFSZ(p), fmt, t);
			break;
		case 'c':
			if (isnum(x)) {
				if ((int)getfval(x))
					snprintf(p, BUFSZ(p), fmt, (int) getfval(x));
				else {
					*p++ = '\0'; /* explicit null byte */
					*p = '\0';   /* next output will start here */
				}
			} else
				snprintf(p, BUFSZ(p), fmt, getsval(x)[0]);
			break;
		default:
			FATAL("can't happen: bad conversion %c in format()", flag);
		}
		tempfree(x);
		p += strlen(p);
		s++;
	}
	*p = '\0';
	free(fmt);
	for ( ; a; a = a->nnext) {		/* evaluate any remaining args */
		x = execute(a);
		tempfree(x);
	}
	*pbuf = buf;
	*pbufsize = bufsize;
	return p - buf;
}

Cell *awksprintf(Node **a, int n)		/* sprintf(a[0]) */
{
	Cell *x;
	Node *y;
	char *buf;
	int bufsz=3*recsize;

	if ((buf = (char *) malloc(bufsz)) == NULL)
		FATAL("out of memory in awksprintf");
	y = a[0]->nnext;
	x = execute(a[0]);
	if (format(&buf, &bufsz, getsval(x), y) == -1)
		FATAL("sprintf string %.30s... too long.  can't happen.", buf);
	tempfree(x);
	x = gettemp();
	x->sval = buf;
	x->tval = STR;
	return(x);
}

Cell *awkprintf(Node **a, int n)		/* printf */
{	/* a[0] is list of args, starting with format string */
	/* a[1] is redirection operator, a[2] is redirection file */
	FILE *fp;
	Cell *x;
	Node *y;
	char *buf;
	int len;
	int bufsz=3*recsize;

	if ((buf = (char *) malloc(bufsz)) == NULL)
		FATAL("out of memory in awkprintf");
	y = a[0]->nnext;
	x = execute(a[0]);
	if ((len = format(&buf, &bufsz, getsval(x), y)) == -1)
		FATAL("printf string %.30s... too long.  can't happen.", buf);
	tempfree(x);
	if (a[1] == NULL) {
		/* fputs(buf, stdout); */
		fwrite(buf, len, 1, stdout);
		if (ferror(stdout))
			FATAL("write error on stdout");
	} else {
		fp = redirect(ptoi(a[1]), a[2]);
		/* fputs(buf, fp); */
		fwrite(buf, len, 1, fp);
		fflush(fp);
		if (ferror(fp))
			FATAL("write error on %s", filename(fp));
	}
	free(buf);
	return(True);
}

Cell *arith(Node **a, int n)	/* a[0] + a[1], etc.  also -a[0] */
{
	Awkfloat i, j = 0;
	double v;
	Cell *x, *y, *z;

	x = execute(a[0]);
	i = getfval(x);
	tempfree(x);
	if (n != UMINUS && n != UPLUS) {
		y = execute(a[1]);
		j = getfval(y);
		tempfree(y);
	}
	z = gettemp();
	switch (n) {
	case ADD:
		i += j;
		break;
	case MINUS:
		i -= j;
		break;
	case MULT:
		i *= j;
		break;
	case DIVIDE:
		if (j == 0)
			FATAL("division by zero");
		i /= j;
		break;
	case MOD:
		if (j == 0)
			FATAL("division by zero in mod");
		modf(i/j, &v);
		i = i - j * v;
		break;
	case UMINUS:
		i = -i;
		break;
	case UPLUS: /* handled by getfval(), above */
		break;
	case POWER:
		if (j >= 0 && modf(j, &v) == 0.0)	/* pos integer exponent */
			i = ipow(i, (int) j);
               else {
			errno = 0;
			i = errcheck(pow(i, j), "pow");
               }
		break;
	default:	/* can't happen */
		FATAL("illegal arithmetic operator %d", n);
	}
	setfval(z, i);
	return(z);
}

double ipow(double x, int n)	/* x**n.  ought to be done by pow, but isn't always */
{
	double v;

	if (n <= 0)
		return 1;
	v = ipow(x, n/2);
	if (n % 2 == 0)
		return v * v;
	else
		return x * v * v;
}

Cell *incrdecr(Node **a, int n)		/* a[0]++, etc. */
{
	Cell *x, *z;
	int k;
	Awkfloat xf;

	x = execute(a[0]);
	xf = getfval(x);
	k = (n == PREINCR || n == POSTINCR) ? 1 : -1;
	if (n == PREINCR || n == PREDECR) {
		setfval(x, xf + k);
		return(x);
	}
	z = gettemp();
	setfval(z, xf);
	setfval(x, xf + k);
	tempfree(x);
	return(z);
}

Cell *assign(Node **a, int n)	/* a[0] = a[1], a[0] += a[1], etc. */
{		/* this is subtle; don't muck with it. */
	Cell *x, *y;
	Awkfloat xf, yf;
	double v;

	y = execute(a[1]);
	x = execute(a[0]);
	if (n == ASSIGN) {	/* ordinary assignment */
		if (x == y && !(x->tval & (FLD|REC)) && x != nfloc)
			;	/* self-assignment: leave alone unless it's a field or NF */
		else if ((y->tval & (STR|NUM)) == (STR|NUM)) {
			setsval(x, getsval(y));
			x->fval = getfval(y);
			x->tval |= NUM;
		}
		else if (isstr(y))
			setsval(x, getsval(y));
		else if (isnum(y))
			setfval(x, getfval(y));
		else
			funnyvar(y, "read value of");
		tempfree(y);
		return(x);
	}
	xf = getfval(x);
	yf = getfval(y);
	switch (n) {
	case ADDEQ:
		xf += yf;
		break;
	case SUBEQ:
		xf -= yf;
		break;
	case MULTEQ:
		xf *= yf;
		break;
	case DIVEQ:
		if (yf == 0)
			FATAL("division by zero in /=");
		xf /= yf;
		break;
	case MODEQ:
		if (yf == 0)
			FATAL("division by zero in %%=");
		modf(xf/yf, &v);
		xf = xf - yf * v;
		break;
	case POWEQ:
		if (yf >= 0 && modf(yf, &v) == 0.0)	/* pos integer exponent */
			xf = ipow(xf, (int) yf);
               else {
			errno = 0;
			xf = errcheck(pow(xf, yf), "pow");
               }
		break;
	default:
		FATAL("illegal assignment operator %d", n);
		break;
	}
	tempfree(y);
	setfval(x, xf);
	return(x);
}

Cell *cat(Node **a, int q)	/* a[0] cat a[1] */
{
	Cell *x, *y, *z;
	int n1, n2;
	char *s = NULL;
	int ssz = 0;

	x = execute(a[0]);
	n1 = strlen(getsval(x));
	adjbuf(&s, &ssz, n1 + 1, recsize, 0, "cat1");
	memcpy(s, x->sval, n1);

	tempfree(x);

	y = execute(a[1]);
	n2 = strlen(getsval(y));
	adjbuf(&s, &ssz, n1 + n2 + 1, recsize, 0, "cat2");
	memcpy(s + n1, y->sval, n2);
	s[n1 + n2] = '\0';

	tempfree(y);

	z = gettemp();
	z->sval = s;
	z->tval = STR;

	return(z);
}

Cell *pastat(Node **a, int n)	/* a[0] { a[1] } */
{
	Cell *x;

	if (a[0] == NULL)
		x = execute(a[1]);
	else {
		x = execute(a[0]);
		if (istrue(x)) {
			tempfree(x);
			x = execute(a[1]);
		}
	}
	return x;
}

Cell *dopa2(Node **a, int n)	/* a[0], a[1] { a[2] } */
{
	Cell *x;
	int pair;

	pair = ptoi(a[3]);
	if (pairstack[pair] == 0) {
		x = execute(a[0]);
		if (istrue(x))
			pairstack[pair] = 1;
		tempfree(x);
	}
	if (pairstack[pair] == 1) {
		x = execute(a[1]);
		if (istrue(x))
			pairstack[pair] = 0;
		tempfree(x);
		x = execute(a[2]);
		return(x);
	}
	return(False);
}

Cell *split(Node **a, int nnn)	/* split(a[0], a[1], a[2]); a[3] is type */
{
	Cell *x = NULL, *y, *ap;
	const char *s, *origs, *t;
	const char *fs = NULL;
	char *origfs = NULL;
	int sep;
	char temp, num[50];
	int n, tempstat, arg3type;
	double result;

	y = execute(a[0]);	/* source string */
	origs = s = strdup(getsval(y));
	tempfree(y);
	arg3type = ptoi(a[3]);
	if (a[2] == NULL)		/* fs string */
		fs = getsval(fsloc);
	else if (arg3type == STRING) {	/* split(str,arr,"string") */
		x = execute(a[2]);
		fs = origfs = strdup(getsval(x));
		tempfree(x);
	} else if (arg3type == REGEXPR)
		fs = "(regexpr)";	/* split(str,arr,/regexpr/) */
	else
		FATAL("illegal type of split");
	sep = *fs;
	ap = execute(a[1]);	/* array name */
	freesymtab(ap);
	DPRINTF("split: s=|%s|, a=%s, sep=|%s|\n", s, NN(ap->nval), fs);
	ap->tval &= ~STR;
	ap->tval |= ARR;
	ap->sval = (char *) makesymtab(NSYMTAB);

	n = 0;
        if (arg3type == REGEXPR && strlen((char*)((fa*)a[2])->restr) == 0) {
		/* split(s, a, //); have to arrange that it looks like empty sep */
		arg3type = 0;
		fs = "";
		sep = 0;
	}
	if (*s != '\0' && (strlen(fs) > 1 || arg3type == REGEXPR)) {	/* reg expr */
		fa *pfa;
		if (arg3type == REGEXPR) {	/* it's ready already */
			pfa = (fa *) a[2];
		} else {
			pfa = makedfa(fs, 1);
		}
		if (nematch(pfa,s)) {
			tempstat = pfa->initstat;
			pfa->initstat = 2;
			do {
				n++;
				snprintf(num, sizeof(num), "%d", n);
				temp = *patbeg;
				setptr(patbeg, '\0');
				if (is_number(s, & result))
					setsymtab(num, s, result, STR|NUM, (Array *) ap->sval);
				else
					setsymtab(num, s, 0.0, STR, (Array *) ap->sval);
				setptr(patbeg, temp);
				s = patbeg + patlen;
				if (*(patbeg+patlen-1) == '\0' || *s == '\0') {
					n++;
					snprintf(num, sizeof(num), "%d", n);
					setsymtab(num, "", 0.0, STR, (Array *) ap->sval);
					pfa->initstat = tempstat;
					goto spdone;
				}
			} while (nematch(pfa,s));
			pfa->initstat = tempstat; 	/* bwk: has to be here to reset */
							/* cf gsub and refldbld */
		}
		n++;
		snprintf(num, sizeof(num), "%d", n);
		if (is_number(s, & result))
			setsymtab(num, s, result, STR|NUM, (Array *) ap->sval);
		else
			setsymtab(num, s, 0.0, STR, (Array *) ap->sval);
  spdone:
		pfa = NULL;
	} else if (sep == ' ') {
		for (n = 0; ; ) {
#define ISWS(c)	((c) == ' ' || (c) == '\t' || (c) == '\n')
			while (ISWS(*s))
				s++;
			if (*s == '\0')
				break;
			n++;
			t = s;
			do
				s++;
			while (*s != '\0' && !ISWS(*s));
			temp = *s;
			setptr(s, '\0');
			snprintf(num, sizeof(num), "%d", n);
			if (is_number(t, & result))
				setsymtab(num, t, result, STR|NUM, (Array *) ap->sval);
			else
				setsymtab(num, t, 0.0, STR, (Array *) ap->sval);
			setptr(s, temp);
			if (*s != '\0')
				s++;
		}
	} else if (sep == 0) {	/* new: split(s, a, "") => 1 char/elem */
		for (n = 0; *s != '\0'; s++) {
			char buf[2];
			n++;
			snprintf(num, sizeof(num), "%d", n);
			buf[0] = *s;
			buf[1] = '\0';
			if (isdigit((uschar)buf[0]))
				setsymtab(num, buf, atof(buf), STR|NUM, (Array *) ap->sval);
			else
				setsymtab(num, buf, 0.0, STR, (Array *) ap->sval);
		}
	} else if (*s != '\0') {
		for (;;) {
			n++;
			t = s;
			while (*s != sep && *s != '\n' && *s != '\0')
				s++;
			temp = *s;
			setptr(s, '\0');
			snprintf(num, sizeof(num), "%d", n);
			if (is_number(t, & result))
				setsymtab(num, t, result, STR|NUM, (Array *) ap->sval);
			else
				setsymtab(num, t, 0.0, STR, (Array *) ap->sval);
			setptr(s, temp);
			if (*s++ == '\0')
				break;
		}
	}
	tempfree(ap);
	xfree(origs);
	xfree(origfs);
	x = gettemp();
	x->tval = NUM;
	x->fval = n;
	return(x);
}

Cell *condexpr(Node **a, int n)	/* a[0] ? a[1] : a[2] */
{
	Cell *x;

	x = execute(a[0]);
	if (istrue(x)) {
		tempfree(x);
		x = execute(a[1]);
	} else {
		tempfree(x);
		x = execute(a[2]);
	}
	return(x);
}

Cell *ifstat(Node **a, int n)	/* if (a[0]) a[1]; else a[2] */
{
	Cell *x;

	x = execute(a[0]);
	if (istrue(x)) {
		tempfree(x);
		x = execute(a[1]);
	} else if (a[2] != NULL) {
		tempfree(x);
		x = execute(a[2]);
	}
	return(x);
}

Cell *whilestat(Node **a, int n)	/* while (a[0]) a[1] */
{
	Cell *x;

	for (;;) {
		x = execute(a[0]);
		if (!istrue(x))
			return(x);
		tempfree(x);
		x = execute(a[1]);
		if (isbreak(x)) {
			x = True;
			return(x);
		}
		if (isnext(x) || isexit(x) || isret(x))
			return(x);
		tempfree(x);
	}
}

Cell *dostat(Node **a, int n)	/* do a[0]; while(a[1]) */
{
	Cell *x;

	for (;;) {
		x = execute(a[0]);
		if (isbreak(x))
			return True;
		if (isnext(x) || isexit(x) || isret(x))
			return(x);
		tempfree(x);
		x = execute(a[1]);
		if (!istrue(x))
			return(x);
		tempfree(x);
	}
}

Cell *forstat(Node **a, int n)	/* for (a[0]; a[1]; a[2]) a[3] */
{
	Cell *x;

	x = execute(a[0]);
	tempfree(x);
	for (;;) {
		if (a[1]!=NULL) {
			x = execute(a[1]);
			if (!istrue(x)) return(x);
			else tempfree(x);
		}
		x = execute(a[3]);
		if (isbreak(x))		/* turn off break */
			return True;
		if (isnext(x) || isexit(x) || isret(x))
			return(x);
		tempfree(x);
		x = execute(a[2]);
		tempfree(x);
	}
}

Cell *instat(Node **a, int n)	/* for (a[0] in a[1]) a[2] */
{
	Cell *x, *vp, *arrayp, *cp, *ncp;
	Array *tp;
	int i;

	vp = execute(a[0]);
	arrayp = execute(a[1]);
	if (!isarr(arrayp)) {
		return True;
	}
	tp = (Array *) arrayp->sval;
	tempfree(arrayp);
	for (i = 0; i < tp->size; i++) {	/* this routine knows too much */
		for (cp = tp->tab[i]; cp != NULL; cp = ncp) {
			setsval(vp, cp->nval);
			ncp = cp->cnext;
			x = execute(a[2]);
			if (isbreak(x)) {
				tempfree(vp);
				return True;
			}
			if (isnext(x) || isexit(x) || isret(x)) {
				tempfree(vp);
				return(x);
			}
			tempfree(x);
		}
	}
	return True;
}

static char *nawk_convert(const char *s, int (*fun_c)(int),
    wint_t (*fun_wc)(wint_t))
{
	char *buf      = NULL;
	char *pbuf     = NULL;
	const char *ps = NULL;
	size_t n       = 0;
	wchar_t wc;
	size_t sz = MB_CUR_MAX;

	if (sz == 1) {
		buf = tostring(s);

		for (pbuf = buf; *pbuf; pbuf++)
			*pbuf = fun_c((uschar)*pbuf);

		return buf;
	} else {
		/* upper/lower character may be shorter/longer */
		buf = tostringN(s, strlen(s) * sz + 1);

		(void) mbtowc(NULL, NULL, 0);	/* reset internal state */
		/*
		 * Reset internal state here too.
		 * Assign result to avoid a compiler warning. (Casting to void
		 * doesn't work.)
		 * Increment said variable to avoid a different warning.
		 */
		int unused = wctomb(NULL, L'\0');
		unused++;

		ps   = s;
		pbuf = buf;
		while (n = mbtowc(&wc, ps, sz),
		       n > 0 && n != (size_t)-1 && n != (size_t)-2)
		{
			ps += n;

			n = wctomb(pbuf, fun_wc(wc));
			if (n == (size_t)-1)
				FATAL("illegal wide character %s", s);

			pbuf += n;
		}

		*pbuf = '\0';

		if (n)
			FATAL("illegal byte sequence %s", s);

		return buf;
	}
}

#ifdef __DJGPP__
static wint_t towupper(wint_t wc)
{
	if (wc >= 0 && wc < 256)
		return toupper(wc & 0xFF);

	return wc;
}

static wint_t towlower(wint_t wc)
{
	if (wc >= 0 && wc < 256)
		return tolower(wc & 0xFF);

	return wc;
}
#endif

static char *nawk_toupper(const char *s)
{
	return nawk_convert(s, toupper, towupper);
}

static char *nawk_tolower(const char *s)
{
	return nawk_convert(s, tolower, towlower);
}

Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg list */
{
	Cell *x, *y;
	Awkfloat u;
	int t;
	Awkfloat tmp;
	char *buf;
	Node *nextarg;
	FILE *fp;
	int status = 0;

	t = ptoi(a[0]);
	x = execute(a[1]);
	nextarg = a[1]->nnext;
	switch (t) {
	case FLENGTH:
		if (isarr(x))
			u = ((Array *) x->sval)->nelem;	/* GROT.  should be function*/
		else
			u = strlen(getsval(x));
		break;
	case FLOG:
		errno = 0;
		u = errcheck(log(getfval(x)), "log");
		break;
	case FINT:
		modf(getfval(x), &u); break;
	case FEXP:
		errno = 0;
		u = errcheck(exp(getfval(x)), "exp");
		break;
	case FSQRT:
		errno = 0;
		u = errcheck(sqrt(getfval(x)), "sqrt");
		break;
	case FSIN:
		u = sin(getfval(x)); break;
	case FCOS:
		u = cos(getfval(x)); break;
	case FATAN:
		if (nextarg == NULL) {
			WARNING("atan2 requires two arguments; returning 1.0");
			u = 1.0;
		} else {
			y = execute(a[1]->nnext);
			u = atan2(getfval(x), getfval(y));
			tempfree(y);
			nextarg = nextarg->nnext;
		}
		break;
	case FSYSTEM:
		fflush(stdout);		/* in case something is buffered already */
		status = system(getsval(x));
		u = status;
		if (status != -1) {
			if (WIFEXITED(status)) {
				u = WEXITSTATUS(status);
			} else if (WIFSIGNALED(status)) {
				u = WTERMSIG(status) + 256;
#ifdef WCOREDUMP
				if (WCOREDUMP(status))
					u += 256;
#endif
			} else	/* something else?!? */
				u = 0;
		}
		break;
	case FRAND:
		/* random() returns numbers in [0..2^31-1]
		 * in order to get a number in [0, 1), divide it by 2^31
		 */
		u = (Awkfloat) random() / (0x7fffffffL + 0x1UL);
		break;
	case FSRAND:
		if (isrec(x))	/* no argument provided */
			u = time((time_t *)0);
		else
			u = getfval(x);
		tmp = u;
		srandom((unsigned long) u);
		u = srand_seed;
		srand_seed = tmp;
		break;
	case FTOUPPER:
	case FTOLOWER:
		if (t == FTOUPPER)
			buf = nawk_toupper(getsval(x));
		else
			buf = nawk_tolower(getsval(x));
		tempfree(x);
		x = gettemp();
		setsval(x, buf);
		free(buf);
		return x;
	case FFLUSH:
		if (isrec(x) || strlen(getsval(x)) == 0) {
			flush_all();	/* fflush() or fflush("") -> all */
			u = 0;
		} else if ((fp = openfile(FFLUSH, getsval(x), NULL)) == NULL)
			u = EOF;
		else
			u = fflush(fp);
		break;
	default:	/* can't happen */
		FATAL("illegal function type %d", t);
		break;
	}
	tempfree(x);
	x = gettemp();
	setfval(x, u);
	if (nextarg != NULL) {
		WARNING("warning: function has too many arguments");
		for ( ; nextarg; nextarg = nextarg->nnext) {
			y = execute(nextarg);
			tempfree(y);
		}
	}
	return(x);
}

Cell *printstat(Node **a, int n)	/* print a[0] */
{
	Node *x;
	Cell *y;
	FILE *fp;

	if (a[1] == NULL)	/* a[1] is redirection operator, a[2] is file */
		fp = stdout;
	else
		fp = redirect(ptoi(a[1]), a[2]);
	for (x = a[0]; x != NULL; x = x->nnext) {
		y = execute(x);
		fputs(getpssval(y), fp);
		tempfree(y);
		if (x->nnext == NULL)
			fputs(getsval(orsloc), fp);
		else
			fputs(getsval(ofsloc), fp);
	}
	if (a[1] != NULL)
		fflush(fp);
	if (ferror(fp))
		FATAL("write error on %s", filename(fp));
	return(True);
}

Cell *nullproc(Node **a, int n)
{
	return 0;
}


FILE *redirect(int a, Node *b)	/* set up all i/o redirections */
{
	FILE *fp;
	Cell *x;
	char *fname;

	x = execute(b);
	fname = getsval(x);
	fp = openfile(a, fname, NULL);
	if (fp == NULL)
		FATAL("can't open file %s", fname);
	tempfree(x);
	return fp;
}

struct files {
	FILE	*fp;
	const char	*fname;
	int	mode;	/* '|', 'a', 'w' => LE/LT, GT */
} *files;

size_t nfiles;

static void stdinit(void)	/* in case stdin, etc., are not constants */
{
	nfiles = FOPEN_MAX;
	files = (struct files *) calloc(nfiles, sizeof(*files));
	if (files == NULL)
		FATAL("can't allocate file memory for %zu files", nfiles);
        files[0].fp = stdin;
	files[0].fname = tostring("/dev/stdin");
	files[0].mode = LT;
        files[1].fp = stdout;
	files[1].fname = tostring("/dev/stdout");
	files[1].mode = GT;
        files[2].fp = stderr;
	files[2].fname = tostring("/dev/stderr");
	files[2].mode = GT;
}

FILE *openfile(int a, const char *us, bool *pnewflag)
{
	const char *s = us;
	size_t i;
	int m;
	FILE *fp = NULL;

	if (*s == '\0')
		FATAL("null file name in print or getline");
	for (i = 0; i < nfiles; i++)
		if (files[i].fname && strcmp(s, files[i].fname) == 0 &&
		    (a == files[i].mode || (a==APPEND && files[i].mode==GT) ||
		     a == FFLUSH)) {
			if (pnewflag)
				*pnewflag = false;
			return files[i].fp;
		}
	if (a == FFLUSH)	/* didn't find it, so don't create it! */
		return NULL;

	for (i = 0; i < nfiles; i++)
		if (files[i].fp == NULL)
			break;
	if (i >= nfiles) {
		struct files *nf;
		size_t nnf = nfiles + FOPEN_MAX;
		nf = (struct files *) realloc(files, nnf * sizeof(*nf));
		if (nf == NULL)
			FATAL("cannot grow files for %s and %zu files", s, nnf);
		memset(&nf[nfiles], 0, FOPEN_MAX * sizeof(*nf));
		nfiles = nnf;
		files = nf;
	}
	fflush(stdout);	/* force a semblance of order */
	m = a;
	if (a == GT) {
		fp = fopen(s, "w");
	} else if (a == APPEND) {
		fp = fopen(s, "a");
		m = GT;	/* so can mix > and >> */
	} else if (a == '|') {	/* output pipe */
		fp = popen(s, "w");
	} else if (a == LE) {	/* input pipe */
		fp = popen(s, "r");
	} else if (a == LT) {	/* getline <file */
		fp = strcmp(s, "-") == 0 ? stdin : fopen(s, "r");	/* "-" is stdin */
	} else	/* can't happen */
		FATAL("illegal redirection %d", a);
	if (fp != NULL) {
		files[i].fname = tostring(s);
		files[i].fp = fp;
		files[i].mode = m;
		if (pnewflag)
			*pnewflag = true;
		if (fp != stdin && fp != stdout && fp != stderr)
			(void) fcntl(fileno(fp), F_SETFD, FD_CLOEXEC);
	}
	return fp;
}

const char *filename(FILE *fp)
{
	size_t i;

	for (i = 0; i < nfiles; i++)
		if (fp == files[i].fp)
			return files[i].fname;
	return "???";
}

Cell *closefile(Node **a, int n)
{
 	Cell *x;
	size_t i;
	bool stat;

 	x = execute(a[0]);
 	getsval(x);
	stat = true;
 	for (i = 0; i < nfiles; i++) {
		if (!files[i].fname || strcmp(x->sval, files[i].fname) != 0)
			continue;
		if (files[i].mode == GT || files[i].mode == '|')
			fflush(files[i].fp);
		if (ferror(files[i].fp)) {
			if ((files[i].mode == GT && files[i].fp != stderr)
			  || files[i].mode == '|')
				FATAL("write error on %s", files[i].fname);
			else
				WARNING("i/o error occurred on %s", files[i].fname);
		}
		if (files[i].fp == stdin || files[i].fp == stdout ||
		    files[i].fp == stderr)
			stat = freopen("/dev/null", "r+", files[i].fp) == NULL;
		else if (files[i].mode == '|' || files[i].mode == LE)
			stat = pclose(files[i].fp) == -1;
		else
			stat = fclose(files[i].fp) == EOF;
		if (stat)
			WARNING("i/o error occurred closing %s", files[i].fname);
		xfree(files[i].fname);
		files[i].fname = NULL;	/* watch out for ref thru this */
		files[i].fp = NULL;
		break;
 	}
 	tempfree(x);
 	x = gettemp();
	setfval(x, (Awkfloat) (stat ? -1 : 0));
 	return(x);
}

void closeall(void)
{
	size_t i;
	bool stat = false;

	for (i = 0; i < nfiles; i++) {
		if (! files[i].fp)
			continue;
		if (files[i].mode == GT || files[i].mode == '|')
			fflush(files[i].fp);
		if (ferror(files[i].fp)) {
			if ((files[i].mode == GT && files[i].fp != stderr)
			  || files[i].mode == '|')
				FATAL("write error on %s", files[i].fname);
			else
				WARNING("i/o error occurred on %s", files[i].fname);
		}
		if (files[i].fp == stdin || files[i].fp == stdout ||
		    files[i].fp == stderr)
			continue;
		if (files[i].mode == '|' || files[i].mode == LE)
			stat = pclose(files[i].fp) == -1;
		else
			stat = fclose(files[i].fp) == EOF;
		if (stat)
			WARNING("i/o error occurred while closing %s", files[i].fname);
	}
}

static void flush_all(void)
{
	size_t i;

	for (i = 0; i < nfiles; i++)
		if (files[i].fp)
			fflush(files[i].fp);
}

void backsub(char **pb_ptr, const char **sptr_ptr);

Cell *sub(Node **a, int nnn)	/* substitute command */
{
	const char *sptr, *q;
	Cell *x, *y, *result;
	char *t, *buf, *pb;
	fa *pfa;
	int bufsz = recsize;

	if ((buf = (char *) malloc(bufsz)) == NULL)
		FATAL("out of memory in sub");
	x = execute(a[3]);	/* target string */
	t = getsval(x);
	if (a[0] == NULL)	/* 0 => a[1] is already-compiled regexpr */
		pfa = (fa *) a[1];	/* regular expression */
	else {
		y = execute(a[1]);
		pfa = makedfa(getsval(y), 1);
		tempfree(y);
	}
	y = execute(a[2]);	/* replacement string */
	result = False;
	if (pmatch(pfa, t)) {
		sptr = t;
		adjbuf(&buf, &bufsz, 1+patbeg-sptr, recsize, 0, "sub");
		pb = buf;
		while (sptr < patbeg)
			*pb++ = *sptr++;
		sptr = getsval(y);
		while (*sptr != '\0') {
			adjbuf(&buf, &bufsz, 5+pb-buf, recsize, &pb, "sub");
			if (*sptr == '\\') {
				backsub(&pb, &sptr);
			} else if (*sptr == '&') {
				sptr++;
				adjbuf(&buf, &bufsz, 1+patlen+pb-buf, recsize, &pb, "sub");
				for (q = patbeg; q < patbeg+patlen; )
					*pb++ = *q++;
			} else
				*pb++ = *sptr++;
		}
		*pb = '\0';
		if (pb > buf + bufsz)
			FATAL("sub result1 %.30s too big; can't happen", buf);
		sptr = patbeg + patlen;
		if ((patlen == 0 && *patbeg) || (patlen && *(sptr-1))) {
			adjbuf(&buf, &bufsz, 1+strlen(sptr)+pb-buf, 0, &pb, "sub");
			while ((*pb++ = *sptr++) != '\0')
				continue;
		}
		if (pb > buf + bufsz)
			FATAL("sub result2 %.30s too big; can't happen", buf);
		setsval(x, buf);	/* BUG: should be able to avoid copy */
		result = True;
	}
	tempfree(x);
	tempfree(y);
	free(buf);
	return result;
}

Cell *gsub(Node **a, int nnn)	/* global substitute */
{
	Cell *x, *y;
	char *rptr, *pb;
	const char *q, *t, *sptr;
	char *buf;
	fa *pfa;
	int mflag, tempstat, num;
	int bufsz = recsize;

	if ((buf = (char *) malloc(bufsz)) == NULL)
		FATAL("out of memory in gsub");
	mflag = 0;	/* if mflag == 0, can replace empty string */
	num = 0;
	x = execute(a[3]);	/* target string */
	t = getsval(x);
	if (a[0] == NULL)	/* 0 => a[1] is already-compiled regexpr */
		pfa = (fa *) a[1];	/* regular expression */
	else {
		y = execute(a[1]);
		pfa = makedfa(getsval(y), 1);
		tempfree(y);
	}
	y = execute(a[2]);	/* replacement string */
	if (pmatch(pfa, t)) {
		tempstat = pfa->initstat;
		pfa->initstat = 2;
		pb = buf;
		rptr = getsval(y);
		do {
			if (patlen == 0 && *patbeg != '\0') {	/* matched empty string */
				if (mflag == 0) {	/* can replace empty */
					num++;
					sptr = rptr;
					while (*sptr != '\0') {
						adjbuf(&buf, &bufsz, 5+pb-buf, recsize, &pb, "gsub");
						if (*sptr == '\\') {
							backsub(&pb, &sptr);
						} else if (*sptr == '&') {
							sptr++;
							adjbuf(&buf, &bufsz, 1+patlen+pb-buf, recsize, &pb, "gsub");
							for (q = patbeg; q < patbeg+patlen; )
								*pb++ = *q++;
						} else
							*pb++ = *sptr++;
					}
				}
				if (*t == '\0')	/* at end */
					goto done;
				adjbuf(&buf, &bufsz, 2+pb-buf, recsize, &pb, "gsub");
				*pb++ = *t++;
				if (pb > buf + bufsz)	/* BUG: not sure of this test */
					FATAL("gsub result0 %.30s too big; can't happen", buf);
				mflag = 0;
			}
			else {	/* matched nonempty string */
				num++;
				sptr = t;
				adjbuf(&buf, &bufsz, 1+(patbeg-sptr)+pb-buf, recsize, &pb, "gsub");
				while (sptr < patbeg)
					*pb++ = *sptr++;
				sptr = rptr;
				while (*sptr != '\0') {
					adjbuf(&buf, &bufsz, 5+pb-buf, recsize, &pb, "gsub");
					if (*sptr == '\\') {
						backsub(&pb, &sptr);
					} else if (*sptr == '&') {
						sptr++;
						adjbuf(&buf, &bufsz, 1+patlen+pb-buf, recsize, &pb, "gsub");
						for (q = patbeg; q < patbeg+patlen; )
							*pb++ = *q++;
					} else
						*pb++ = *sptr++;
				}
				t = patbeg + patlen;
				if (patlen == 0 || *t == '\0' || *(t-1) == '\0')
					goto done;
				if (pb > buf + bufsz)
					FATAL("gsub result1 %.30s too big; can't happen", buf);
				mflag = 1;
			}
		} while (pmatch(pfa,t));
		sptr = t;
		adjbuf(&buf, &bufsz, 1+strlen(sptr)+pb-buf, 0, &pb, "gsub");
		while ((*pb++ = *sptr++) != '\0')
			continue;
	done:	if (pb < buf + bufsz)
			*pb = '\0';
		else if (*(pb-1) != '\0')
			FATAL("gsub result2 %.30s truncated; can't happen", buf);
		setsval(x, buf);	/* BUG: should be able to avoid copy + free */
		pfa->initstat = tempstat;
	}
	tempfree(x);
	tempfree(y);
	x = gettemp();
	x->tval = NUM;
	x->fval = num;
	free(buf);
	return(x);
}

void backsub(char **pb_ptr, const char **sptr_ptr)	/* handle \\& variations */
{						/* sptr[0] == '\\' */
	char *pb = *pb_ptr;
	const char *sptr = *sptr_ptr;
	static bool first = true;
	static bool do_posix = false;

	if (first) {
		first = false;
		do_posix = (getenv("POSIXLY_CORRECT") != NULL);
	}

	if (sptr[1] == '\\') {
		if (sptr[2] == '\\' && sptr[3] == '&') { /* \\\& -> \& */
			*pb++ = '\\';
			*pb++ = '&';
			sptr += 4;
		} else if (sptr[2] == '&') {	/* \\& -> \ + matched */
			*pb++ = '\\';
			sptr += 2;
		} else if (do_posix) {		/* \\x -> \x */
			sptr++;
			*pb++ = *sptr++;
		} else {			/* \\x -> \\x */
			*pb++ = *sptr++;
			*pb++ = *sptr++;
		}
	} else if (sptr[1] == '&') {	/* literal & */
		sptr++;
		*pb++ = *sptr++;
	} else				/* literal \ */
		*pb++ = *sptr++;

	*pb_ptr = pb;
	*sptr_ptr = sptr;
}