/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
│ vi: set noet ft=c ts=8 sw=8 fenc=utf-8                                   :vi │
╚──────────────────────────────────────────────────────────────────────────────╝
│                                                                              │
│ 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 "libc/calls/calls.h"
#include "libc/calls/weirdtypes.h"
#include "libc/errno.h"
#include "libc/fmt/conv.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/f.h"
#include "libc/sysv/consts/fd.h"
#include "libc/time/time.h"
#include "third_party/awk/awk.h"
#include "third_party/awk/awkgram.tab.h"
#include "third_party/libcxx/math.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

jmp_buf env;
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 */
		execute(a);
	*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, recsize, 0, "cat1");
	memcpy(s, x->sval, n1);

	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(x);
	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));
	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);
	tempfree(y);
	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;
				if (WCOREDUMP(status))
					u += 256;
			} 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)
			execute(nextarg);
	}
	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;
}