[asperl] Created new branch from win32@396, added AS patch#1

[perl5.git] / sv.c

/*    sv.c
 *
 *    Copyright (c) 1991-1997, Larry Wall
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 */

/*
 * "I wonder what the Entish is for 'yes' and 'no'," he thought.
 */

#include "EXTERN.h"
#include "perl.h"

#ifdef OVR_DBL_DIG
/* Use an overridden DBL_DIG */
# ifdef DBL_DIG
#  undef DBL_DIG
# endif
# define DBL_DIG OVR_DBL_DIG
#else
/* The following is all to get DBL_DIG, in order to pick a nice
   default value for printing floating point numbers in Gconvert.
   (see config.h)
*/
#ifdef I_LIMITS
#include <limits.h>
#endif
#ifdef I_FLOAT
#include <float.h>
#endif
#ifndef HAS_DBL_DIG
#define DBL_DIG	15   /* A guess that works lots of places */
#endif
#endif

#if defined(USE_STDIO_PTR) && defined(STDIO_PTR_LVALUE) && defined(STDIO_CNT_LVALUE) && !defined(__QNX__)
#  define FAST_SV_GETS
#endif

static IV asIV _((SV* sv));
static UV asUV _((SV* sv));
static SV *more_sv _((void));
static XPVIV *more_xiv _((void));
static XPVNV *more_xnv _((void));
static XPV *more_xpv _((void));
static XRV *more_xrv _((void));
static XPVIV *new_xiv _((void));
static XPVNV *new_xnv _((void));
static XPV *new_xpv _((void));
static XRV *new_xrv _((void));
static void del_xiv _((XPVIV* p));
static void del_xnv _((XPVNV* p));
static void del_xpv _((XPV* p));
static void del_xrv _((XRV* p));
static void sv_mortalgrow _((void));
static void sv_unglob _((SV* sv));
static void sv_check_thinkfirst _((SV *sv));

typedef void (*SVFUNC) _((SV*));

#ifdef PURIFY

#define new_SV(p)			\
    do {				\
	MUTEX_LOCK(&sv_mutex);		\
	(p) = (SV*)safemalloc(sizeof(SV)); \
	reg_add(p);			\
	MUTEX_UNLOCK(&sv_mutex);	\
    } while (0)

#define del_SV(p)			\
    do {				\
	MUTEX_LOCK(&sv_mutex);		\
	reg_remove(p);			\
        Safefree((char*)(p));		\
	MUTEX_UNLOCK(&sv_mutex);	\
    } while (0)

static SV **registry;
static I32 regsize;

#define REGHASH(sv,size)  ((((U32)(sv)) >> 2) % (size))

#define REG_REPLACE(sv,a,b) \
    do {				\
	void* p = sv->sv_any;		\
	I32 h = REGHASH(sv, regsize);	\
	I32 i = h;			\
	while (registry[i] != (a)) {	\
	    if (++i >= regsize)		\
		i = 0;			\
	    if (i == h)			\
		die("SV registry bug");	\
	}				\
	registry[i] = (b);		\
    } while (0)

#define REG_ADD(sv)	REG_REPLACE(sv,Nullsv,sv)
#define REG_REMOVE(sv)	REG_REPLACE(sv,sv,Nullsv)

static void
reg_add(sv)
SV* sv;
{
    if (sv_count >= (regsize >> 1))
    {
	SV **oldreg = registry;
	I32 oldsize = regsize;

	regsize = regsize ? ((regsize << 2) + 1) : 2037;
	registry = (SV**)safemalloc(regsize * sizeof(SV*));
	memzero(registry, regsize * sizeof(SV*));

	if (oldreg) {
	    I32 i;

	    for (i = 0; i < oldsize; ++i) {
		SV* oldsv = oldreg[i];
		if (oldsv)
		    REG_ADD(oldsv);
	    }
	    Safefree(oldreg);
	}
    }

    REG_ADD(sv);
    ++sv_count;
}

static void
reg_remove(sv)
SV* sv;
{
    REG_REMOVE(sv);
    --sv_count;
}

static void
visit(f)
SVFUNC f;
{
    I32 i;

    for (i = 0; i < regsize; ++i) {
	SV* sv = registry[i];
	if (sv)
	    (*f)(sv);
    }
}

void
sv_add_arena(ptr, size, flags)
char* ptr;
U32 size;
U32 flags;
{
    if (!(flags & SVf_FAKE))
	Safefree(ptr);
}

#else /* ! PURIFY */

/*
 * "A time to plant, and a time to uproot what was planted..."
 */

#define plant_SV(p)			\
    do {				\
	SvANY(p) = (void *)sv_root;	\
	SvFLAGS(p) = SVTYPEMASK;	\
	sv_root = (p);			\
	--sv_count;			\
    } while (0)

/* sv_mutex must be held while calling uproot_SV() */
#define uproot_SV(p)			\
    do {				\
	(p) = sv_root;			\
	sv_root = (SV*)SvANY(p);	\
	++sv_count;			\
    } while (0)

#define new_SV(p)	do {		\
	MUTEX_LOCK(&sv_mutex);		\
	if (sv_root)			\
	    uproot_SV(p);		\
	else				\
	    (p) = more_sv();		\
	MUTEX_UNLOCK(&sv_mutex);	\
    } while (0)

#ifdef DEBUGGING

#define del_SV(p)	do {		\
	MUTEX_LOCK(&sv_mutex);		\
	if (debug & 32768)		\
	    del_sv(p);			\
	else				\
	    plant_SV(p);		\
	MUTEX_UNLOCK(&sv_mutex);	\
    } while (0)

static void
del_sv(SV *p)
{
    if (debug & 32768) {
	SV* sva;
	SV* sv;
	SV* svend;
	int ok = 0;
	for (sva = sv_arenaroot; sva; sva = (SV *) SvANY(sva)) {
	    sv = sva + 1;
	    svend = &sva[SvREFCNT(sva)];
	    if (p >= sv && p < svend)
		ok = 1;
	}
	if (!ok) {
	    warn("Attempt to free non-arena SV: 0x%lx", (unsigned long)p);
	    return;
	}
    }
    plant_SV(p);
}

#else /* ! DEBUGGING */

#define del_SV(p)   plant_SV(p)

#endif /* DEBUGGING */

void
sv_add_arena(char *ptr, U32 size, U32 flags)
{
    SV* sva = (SV*)ptr;
    register SV* sv;
    register SV* svend;
    Zero(sva, size, char);

    /* The first SV in an arena isn't an SV. */
    SvANY(sva) = (void *) sv_arenaroot;		/* ptr to next arena */
    SvREFCNT(sva) = size / sizeof(SV);		/* number of SV slots */
    SvFLAGS(sva) = flags;			/* FAKE if not to be freed */

    sv_arenaroot = sva;
    sv_root = sva + 1;

    svend = &sva[SvREFCNT(sva) - 1];
    sv = sva + 1;
    while (sv < svend) {
	SvANY(sv) = (void *)(SV*)(sv + 1);
	SvFLAGS(sv) = SVTYPEMASK;
	sv++;
    }
    SvANY(sv) = 0;
    SvFLAGS(sv) = SVTYPEMASK;
}

/* sv_mutex must be held while calling more_sv() */
static SV*
more_sv(void)
{
    register SV* sv;

    if (nice_chunk) {
	sv_add_arena(nice_chunk, nice_chunk_size, 0);
	nice_chunk = Nullch;
    }
    else {
	char *chunk;                /* must use New here to match call to */
	New(704,chunk,1008,char);   /* Safefree() in sv_free_arenas()     */
	sv_add_arena(chunk, 1008, 0);
    }
    uproot_SV(sv);
    return sv;
}

static void
visit(SVFUNC f)
{
    SV* sva;
    SV* sv;
    register SV* svend;

    for (sva = sv_arenaroot; sva; sva = (SV*)SvANY(sva)) {
	svend = &sva[SvREFCNT(sva)];
	for (sv = sva + 1; sv < svend; ++sv) {
	    if (SvTYPE(sv) != SVTYPEMASK)
		(*f)(sv);
	}
    }
}

#endif /* PURIFY */

static void
do_report_used(SV *sv)
{
    if (SvTYPE(sv) != SVTYPEMASK) {
	/* XXX Perhaps this ought to go to Perl_debug_log, if DEBUGGING. */
	PerlIO_printf(PerlIO_stderr(), "****\n");
	sv_dump(sv);
    }
}

void
sv_report_used(void)
{
    visit(do_report_used);
}

static void
do_clean_objs(SV *sv)
{
    SV* rv;

    if (SvROK(sv) && SvOBJECT(rv = SvRV(sv))) {
	DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning object ref:\n "), sv_dump(sv));)
	SvROK_off(sv);
	SvRV(sv) = 0;
	SvREFCNT_dec(rv);
    }

    /* XXX Might want to check arrays, etc. */
}

#ifndef DISABLE_DESTRUCTOR_KLUDGE
static void
do_clean_named_objs(SV *sv)
{
    if (SvTYPE(sv) == SVt_PVGV && GvSV(sv))
	do_clean_objs(GvSV(sv));
}
#endif

static bool in_clean_objs = FALSE;

void
sv_clean_objs(void)
{
    in_clean_objs = TRUE;
#ifndef DISABLE_DESTRUCTOR_KLUDGE
    visit(do_clean_named_objs);
#endif
    visit(do_clean_objs);
    in_clean_objs = FALSE;
}

static void
do_clean_all(SV *sv)
{
    DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning loops:\n "), sv_dump(sv));)
    SvFLAGS(sv) |= SVf_BREAK;
    SvREFCNT_dec(sv);
}

static bool in_clean_all = FALSE;

void
sv_clean_all(void)
{
    in_clean_all = TRUE;
    visit(do_clean_all);
    in_clean_all = FALSE;
}

void
sv_free_arenas(void)
{
    SV* sva;
    SV* svanext;

    /* Free arenas here, but be careful about fake ones.  (We assume
       contiguity of the fake ones with the corresponding real ones.) */

    for (sva = sv_arenaroot; sva; sva = svanext) {
	svanext = (SV*) SvANY(sva);
	while (svanext && SvFAKE(svanext))
	    svanext = (SV*) SvANY(svanext);

	if (!SvFAKE(sva))
	    Safefree((void *)sva);
    }

    sv_arenaroot = 0;
    sv_root = 0;
}

static XPVIV*
new_xiv(void)
{
    IV** xiv;
    if (xiv_root) {
	xiv = xiv_root;
	/*
	 * See comment in more_xiv() -- RAM.
	 */
	xiv_root = (IV**)*xiv;
	return (XPVIV*)((char*)xiv - sizeof(XPV));
    }
    return more_xiv();
}

static void
del_xiv(XPVIV *p)
{
    IV** xiv = (IV**)((char*)(p) + sizeof(XPV));
    *xiv = (IV *)xiv_root;
    xiv_root = xiv;
}

static XPVIV*
more_xiv(void)
{
    register IV** xiv;
    register IV** xivend;
    XPV* ptr = (XPV*)safemalloc(1008);
    ptr->xpv_pv = (char*)xiv_arenaroot;		/* linked list of xiv arenas */
    xiv_arenaroot = ptr;			/* to keep Purify happy */

    xiv = (IV**) ptr;
    xivend = &xiv[1008 / sizeof(IV *) - 1];
    xiv += (sizeof(XPV) - 1) / sizeof(IV *) + 1;   /* fudge by size of XPV */
    xiv_root = xiv;
    while (xiv < xivend) {
	*xiv = (IV *)(xiv + 1);
	xiv++;
    }
    *xiv = 0;
    return new_xiv();
}

static XPVNV*
new_xnv(void)
{
    double* xnv;
    if (xnv_root) {
	xnv = xnv_root;
	xnv_root = *(double**)xnv;
	return (XPVNV*)((char*)xnv - sizeof(XPVIV));
    }
    return more_xnv();
}

static void
del_xnv(XPVNV *p)
{
    double* xnv = (double*)((char*)(p) + sizeof(XPVIV));
    *(double**)xnv = xnv_root;
    xnv_root = xnv;
}

static XPVNV*
more_xnv(void)
{
    register double* xnv;
    register double* xnvend;
    xnv = (double*)safemalloc(1008);
    xnvend = &xnv[1008 / sizeof(double) - 1];
    xnv += (sizeof(XPVIV) - 1) / sizeof(double) + 1; /* fudge by sizeof XPVIV */
    xnv_root = xnv;
    while (xnv < xnvend) {
	*(double**)xnv = (double*)(xnv + 1);
	xnv++;
    }
    *(double**)xnv = 0;
    return new_xnv();
}

static XRV*
new_xrv(void)
{
    XRV* xrv;
    if (xrv_root) {
	xrv = xrv_root;
	xrv_root = (XRV*)xrv->xrv_rv;
	return xrv;
    }
    return more_xrv();
}

static void
del_xrv(XRV *p)
{
    p->xrv_rv = (SV*)xrv_root;
    xrv_root = p;
}

static XRV*
more_xrv(void)
{
    register XRV* xrv;
    register XRV* xrvend;
    xrv_root = (XRV*)safemalloc(1008);
    xrv = xrv_root;
    xrvend = &xrv[1008 / sizeof(XRV) - 1];
    while (xrv < xrvend) {
	xrv->xrv_rv = (SV*)(xrv + 1);
	xrv++;
    }
    xrv->xrv_rv = 0;
    return new_xrv();
}

static XPV*
new_xpv(void)
{
    XPV* xpv;
    if (xpv_root) {
	xpv = xpv_root;
	xpv_root = (XPV*)xpv->xpv_pv;
	return xpv;
    }
    return more_xpv();
}

static void
del_xpv(XPV *p)
{
    p->xpv_pv = (char*)xpv_root;
    xpv_root = p;
}

static XPV*
more_xpv(void)
{
    register XPV* xpv;
    register XPV* xpvend;
    xpv_root = (XPV*)safemalloc(1008);
    xpv = xpv_root;
    xpvend = &xpv[1008 / sizeof(XPV) - 1];
    while (xpv < xpvend) {
	xpv->xpv_pv = (char*)(xpv + 1);
	xpv++;
    }
    xpv->xpv_pv = 0;
    return new_xpv();
}

#ifdef PURIFY
#define new_XIV() (void*)safemalloc(sizeof(XPVIV))
#define del_XIV(p) Safefree((char*)p)
#else
#define new_XIV() (void*)new_xiv()
#define del_XIV(p) del_xiv((XPVIV*) p)
#endif

#ifdef PURIFY
#define new_XNV() (void*)safemalloc(sizeof(XPVNV))
#define del_XNV(p) Safefree((char*)p)
#else
#define new_XNV() (void*)new_xnv()
#define del_XNV(p) del_xnv((XPVNV*) p)
#endif

#ifdef PURIFY
#define new_XRV() (void*)safemalloc(sizeof(XRV))
#define del_XRV(p) Safefree((char*)p)
#else
#define new_XRV() (void*)new_xrv()
#define del_XRV(p) del_xrv((XRV*) p)
#endif

#ifdef PURIFY
#define new_XPV() (void*)safemalloc(sizeof(XPV))
#define del_XPV(p) Safefree((char*)p)
#else
#define new_XPV() (void*)new_xpv()
#define del_XPV(p) del_xpv((XPV *)p)
#endif

#define new_XPVIV() (void*)safemalloc(sizeof(XPVIV))
#define del_XPVIV(p) Safefree((char*)p)

#define new_XPVNV() (void*)safemalloc(sizeof(XPVNV))
#define del_XPVNV(p) Safefree((char*)p)

#define new_XPVMG() (void*)safemalloc(sizeof(XPVMG))
#define del_XPVMG(p) Safefree((char*)p)

#define new_XPVLV() (void*)safemalloc(sizeof(XPVLV))
#define del_XPVLV(p) Safefree((char*)p)

#define new_XPVAV() (void*)safemalloc(sizeof(XPVAV))
#define del_XPVAV(p) Safefree((char*)p)

#define new_XPVHV() (void*)safemalloc(sizeof(XPVHV))
#define del_XPVHV(p) Safefree((char*)p)

#define new_XPVCV() (void*)safemalloc(sizeof(XPVCV))
#define del_XPVCV(p) Safefree((char*)p)

#define new_XPVGV() (void*)safemalloc(sizeof(XPVGV))
#define del_XPVGV(p) Safefree((char*)p)

#define new_XPVBM() (void*)safemalloc(sizeof(XPVBM))
#define del_XPVBM(p) Safefree((char*)p)

#define new_XPVFM() (void*)safemalloc(sizeof(XPVFM))
#define del_XPVFM(p) Safefree((char*)p)

#define new_XPVIO() (void*)safemalloc(sizeof(XPVIO))
#define del_XPVIO(p) Safefree((char*)p)

bool
sv_upgrade(register SV *sv, U32 mt)
{
    char*	pv;
    U32		cur;
    U32		len;
    IV		iv;
    double	nv;
    MAGIC*	magic;
    HV*		stash;

    if (SvTYPE(sv) == mt)
	return TRUE;

    if (mt < SVt_PVIV)
	(void)SvOOK_off(sv);

    switch (SvTYPE(sv)) {
    case SVt_NULL:
	pv	= 0;
	cur	= 0;
	len	= 0;
	iv	= 0;
	nv	= 0.0;
	magic	= 0;
	stash	= 0;
	break;
    case SVt_IV:
	pv	= 0;
	cur	= 0;
	len	= 0;
	iv	= SvIVX(sv);
	nv	= (double)SvIVX(sv);
	del_XIV(SvANY(sv));
	magic	= 0;
	stash	= 0;
	if (mt == SVt_NV)
	    mt = SVt_PVNV;
	else if (mt < SVt_PVIV)
	    mt = SVt_PVIV;
	break;
    case SVt_NV:
	pv	= 0;
	cur	= 0;
	len	= 0;
	nv	= SvNVX(sv);
	iv	= I_32(nv);
	magic	= 0;
	stash	= 0;
	del_XNV(SvANY(sv));
	SvANY(sv) = 0;
	if (mt < SVt_PVNV)
	    mt = SVt_PVNV;
	break;
    case SVt_RV:
	pv	= (char*)SvRV(sv);
	cur	= 0;
	len	= 0;
	iv	= (IV)pv;
	nv	= (double)(unsigned long)pv;
	del_XRV(SvANY(sv));
	magic	= 0;
	stash	= 0;
	break;
    case SVt_PV:
	pv	= SvPVX(sv);
	cur	= SvCUR(sv);
	len	= SvLEN(sv);
	iv	= 0;
	nv	= 0.0;
	magic	= 0;
	stash	= 0;
	del_XPV(SvANY(sv));
	if (mt <= SVt_IV)
	    mt = SVt_PVIV;
	else if (mt == SVt_NV)
	    mt = SVt_PVNV;
	break;
    case SVt_PVIV:
	pv	= SvPVX(sv);
	cur	= SvCUR(sv);
	len	= SvLEN(sv);
	iv	= SvIVX(sv);
	nv	= 0.0;
	magic	= 0;
	stash	= 0;
	del_XPVIV(SvANY(sv));
	break;
    case SVt_PVNV:
	pv	= SvPVX(sv);
	cur	= SvCUR(sv);
	len	= SvLEN(sv);
	iv	= SvIVX(sv);
	nv	= SvNVX(sv);
	magic	= 0;
	stash	= 0;
	del_XPVNV(SvANY(sv));
	break;
    case SVt_PVMG:
	pv	= SvPVX(sv);
	cur	= SvCUR(sv);
	len	= SvLEN(sv);
	iv	= SvIVX(sv);
	nv	= SvNVX(sv);
	magic	= SvMAGIC(sv);
	stash	= SvSTASH(sv);
	del_XPVMG(SvANY(sv));
	break;
    default:
	croak("Can't upgrade that kind of scalar");
    }

    switch (mt) {
    case SVt_NULL:
	croak("Can't upgrade to undef");
    case SVt_IV:
	SvANY(sv) = new_XIV();
	SvIVX(sv)	= iv;
	break;
    case SVt_NV:
	SvANY(sv) = new_XNV();
	SvNVX(sv)	= nv;
	break;
    case SVt_RV:
	SvANY(sv) = new_XRV();
	SvRV(sv) = (SV*)pv;
	break;
    case SVt_PV:
	SvANY(sv) = new_XPV();
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	break;
    case SVt_PVIV:
	SvANY(sv) = new_XPVIV();
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	if (SvNIOK(sv))
	    (void)SvIOK_on(sv);
	SvNOK_off(sv);
	break;
    case SVt_PVNV:
	SvANY(sv) = new_XPVNV();
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	break;
    case SVt_PVMG:
	SvANY(sv) = new_XPVMG();
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	break;
    case SVt_PVLV:
	SvANY(sv) = new_XPVLV();
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	LvTARGOFF(sv)	= 0;
	LvTARGLEN(sv)	= 0;
	LvTARG(sv)	= 0;
	LvTYPE(sv)	= 0;
	break;
    case SVt_PVAV:
	SvANY(sv) = new_XPVAV();
	if (pv)
	    Safefree(pv);
	SvPVX(sv)	= 0;
	AvMAX(sv)	= -1;
	AvFILL(sv)	= -1;
	SvIVX(sv)	= 0;
	SvNVX(sv)	= 0.0;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	AvALLOC(sv)	= 0;
	AvARYLEN(sv)	= 0;
	AvFLAGS(sv)	= 0;
	break;
    case SVt_PVHV:
	SvANY(sv) = new_XPVHV();
	if (pv)
	    Safefree(pv);
	SvPVX(sv)	= 0;
	HvFILL(sv)	= 0;
	HvMAX(sv)	= 0;
	HvKEYS(sv)	= 0;
	SvNVX(sv)	= 0.0;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	HvRITER(sv)	= 0;
	HvEITER(sv)	= 0;
	HvPMROOT(sv)	= 0;
	HvNAME(sv)	= 0;
	break;
    case SVt_PVCV:
	SvANY(sv) = new_XPVCV();
	Zero(SvANY(sv), 1, XPVCV);
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	break;
    case SVt_PVGV:
	SvANY(sv) = new_XPVGV();
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	GvGP(sv)	= 0;
	GvNAME(sv)	= 0;
	GvNAMELEN(sv)	= 0;
	GvSTASH(sv)	= 0;
	GvFLAGS(sv)	= 0;
	break;
    case SVt_PVBM:
	SvANY(sv) = new_XPVBM();
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	BmRARE(sv)	= 0;
	BmUSEFUL(sv)	= 0;
	BmPREVIOUS(sv)	= 0;
	break;
    case SVt_PVFM:
	SvANY(sv) = new_XPVFM();
	Zero(SvANY(sv), 1, XPVFM);
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	break;
    case SVt_PVIO:
	SvANY(sv) = new_XPVIO();
	Zero(SvANY(sv), 1, XPVIO);
	SvPVX(sv)	= pv;
	SvCUR(sv)	= cur;
	SvLEN(sv)	= len;
	SvIVX(sv)	= iv;
	SvNVX(sv)	= nv;
	SvMAGIC(sv)	= magic;
	SvSTASH(sv)	= stash;
	IoPAGE_LEN(sv)	= 60;
	break;
    }
    SvFLAGS(sv) &= ~SVTYPEMASK;
    SvFLAGS(sv) |= mt;
    return TRUE;
}

#ifdef DEBUGGING
char *
sv_peek(SV *sv)
{
    SV *t = sv_newmortal();
    STRLEN prevlen;
    int unref = 0;

    sv_setpvn(t, "", 0);
  retry:
    if (!sv) {
	sv_catpv(t, "VOID");
	goto finish;
    }
    else if (sv == (SV*)0x55555555 || SvTYPE(sv) == 'U') {
	sv_catpv(t, "WILD");
	goto finish;
    }
    else if (sv == &sv_undef || sv == &sv_no || sv == &sv_yes) {
	if (sv == &sv_undef) {
	    sv_catpv(t, "SV_UNDEF");
	    if (!(SvFLAGS(sv) & (SVf_OK|SVf_OOK|SVs_OBJECT|
				 SVs_GMG|SVs_SMG|SVs_RMG)) &&
		SvREADONLY(sv))
		goto finish;
	}
	else if (sv == &sv_no) {
	    sv_catpv(t, "SV_NO");
	    if (!(SvFLAGS(sv) & (SVf_ROK|SVf_OOK|SVs_OBJECT|
				 SVs_GMG|SVs_SMG|SVs_RMG)) &&
		!(~SvFLAGS(sv) & (SVf_POK|SVf_NOK|SVf_READONLY|
				  SVp_POK|SVp_NOK)) &&
		SvCUR(sv) == 0 &&
		SvNVX(sv) == 0.0)
		goto finish;
	}
	else {
	    sv_catpv(t, "SV_YES");
	    if (!(SvFLAGS(sv) & (SVf_ROK|SVf_OOK|SVs_OBJECT|
				 SVs_GMG|SVs_SMG|SVs_RMG)) &&
		!(~SvFLAGS(sv) & (SVf_POK|SVf_NOK|SVf_READONLY|
				  SVp_POK|SVp_NOK)) &&
		SvCUR(sv) == 1 &&
		SvPVX(sv) && *SvPVX(sv) == '1' &&
		SvNVX(sv) == 1.0)
		goto finish;
	}
	sv_catpv(t, ":");
    }
    else if (SvREFCNT(sv) == 0) {
	sv_catpv(t, "(");
	unref++;
    }
    if (SvROK(sv)) {
	sv_catpv(t, "\\");
	if (SvCUR(t) + unref > 10) {
	    SvCUR(t) = unref + 3;
	    *SvEND(t) = '\0';
	    sv_catpv(t, "...");
	    goto finish;
	}
	sv = (SV*)SvRV(sv);
	goto retry;
    }
    switch (SvTYPE(sv)) {
    default:
	sv_catpv(t, "FREED");
	goto finish;

    case SVt_NULL:
	sv_catpv(t, "UNDEF");
	goto finish;
    case SVt_IV:
	sv_catpv(t, "IV");
	break;
    case SVt_NV:
	sv_catpv(t, "NV");
	break;
    case SVt_RV:
	sv_catpv(t, "RV");
	break;
    case SVt_PV:
	sv_catpv(t, "PV");
	break;
    case SVt_PVIV:
	sv_catpv(t, "PVIV");
	break;
    case SVt_PVNV:
	sv_catpv(t, "PVNV");
	break;
    case SVt_PVMG:
	sv_catpv(t, "PVMG");
	break;
    case SVt_PVLV:
	sv_catpv(t, "PVLV");
	break;
    case SVt_PVAV:
	sv_catpv(t, "AV");
	break;
    case SVt_PVHV:
	sv_catpv(t, "HV");
	break;
    case SVt_PVCV:
	if (CvGV(sv))
	    sv_catpvf(t, "CV(%s)", GvNAME(CvGV(sv)));
	else
	    sv_catpv(t, "CV()");
	goto finish;
    case SVt_PVGV:
	sv_catpv(t, "GV");
	break;
    case SVt_PVBM:
	sv_catpv(t, "BM");
	break;
    case SVt_PVFM:
	sv_catpv(t, "FM");
	break;
    case SVt_PVIO:
	sv_catpv(t, "IO");
	break;
    }

    if (SvPOKp(sv)) {
	if (!SvPVX(sv))
	    sv_catpv(t, "(null)");
	if (SvOOK(sv))
	    sv_catpvf(t, "(%ld+\"%.127s\")",(long)SvIVX(sv),SvPVX(sv));
	else
	    sv_catpvf(t, "(\"%.127s\")",SvPVX(sv));
    }
    else if (SvNOKp(sv)) {
	SET_NUMERIC_STANDARD();
	sv_catpvf(t, "(%g)",SvNVX(sv));
    }
    else if (SvIOKp(sv))
	sv_catpvf(t, "(%ld)",(long)SvIVX(sv));
    else
	sv_catpv(t, "()");
    
  finish:
    if (unref) {
	while (unref--)
	    sv_catpv(t, ")");
    }
    return SvPV(t, na);
}
#endif

int
sv_backoff(register SV *sv)
{
    assert(SvOOK(sv));
    if (SvIVX(sv)) {
	char *s = SvPVX(sv);
	SvLEN(sv) += SvIVX(sv);
	SvPVX(sv) -= SvIVX(sv);
	SvIV_set(sv, 0);
	Move(s, SvPVX(sv), SvCUR(sv)+1, char);
    }
    SvFLAGS(sv) &= ~SVf_OOK;
    return 0;
}

char *
#ifndef DOSISH
sv_grow(register SV *sv, register I32 newlen)
#else
sv_grow(SV* sv, unsigned long newlen)
#endif
{
    register char *s;

#ifdef HAS_64K_LIMIT
    if (newlen >= 0x10000) {
	PerlIO_printf(Perl_debug_log, "Allocation too large: %lx\n", newlen);
	my_exit(1);
    }
#endif /* HAS_64K_LIMIT */
    if (SvROK(sv))
	sv_unref(sv);
    if (SvTYPE(sv) < SVt_PV) {
	sv_upgrade(sv, SVt_PV);
	s = SvPVX(sv);
    }
    else if (SvOOK(sv)) {	/* pv is offset? */
	sv_backoff(sv);
	s = SvPVX(sv);
	if (newlen > SvLEN(sv))
	    newlen += 10 * (newlen - SvCUR(sv)); /* avoid copy each time */
    }
    else
	s = SvPVX(sv);
    if (newlen > SvLEN(sv)) {		/* need more room? */
        if (SvLEN(sv) && s)
	    Renew(s,newlen,char);
        else
	    New(703,s,newlen,char);
	SvPV_set(sv, s);
        SvLEN_set(sv, newlen);
    }
    return s;
}

void
sv_setiv(register SV *sv, IV i)
{
    sv_check_thinkfirst(sv);
    switch (SvTYPE(sv)) {
    case SVt_NULL:
	sv_upgrade(sv, SVt_IV);
	break;
    case SVt_NV:
	sv_upgrade(sv, SVt_PVNV);
	break;
    case SVt_RV:
    case SVt_PV:
	sv_upgrade(sv, SVt_PVIV);
	break;

    case SVt_PVGV:
	if (SvFAKE(sv)) {
	    sv_unglob(sv);
	    break;
	}
	/* FALL THROUGH */
    case SVt_PVAV:
    case SVt_PVHV:
    case SVt_PVCV:
    case SVt_PVFM:
    case SVt_PVIO:
	{
	    dTHR;
	    croak("Can't coerce %s to integer in %s", sv_reftype(sv,0),
		  op_desc[op->op_type]);
	}
    }
    (void)SvIOK_only(sv);			/* validate number */
    SvIVX(sv) = i;
    SvTAINT(sv);
}

void
sv_setuv(register SV *sv, UV u)
{
    if (u <= IV_MAX)
	sv_setiv(sv, u);
    else
	sv_setnv(sv, (double)u);
}

void
sv_setnv(register SV *sv, double num)
{
    sv_check_thinkfirst(sv);
    switch (SvTYPE(sv)) {
    case SVt_NULL:
    case SVt_IV:
	sv_upgrade(sv, SVt_NV);
	break;
    case SVt_NV:
    case SVt_RV:
    case SVt_PV:
    case SVt_PVIV:
	sv_upgrade(sv, SVt_PVNV);
	/* FALL THROUGH */
    case SVt_PVNV:
    case SVt_PVMG:
    case SVt_PVBM:
    case SVt_PVLV:
	if (SvOOK(sv))
	    (void)SvOOK_off(sv);
	break;
    case SVt_PVGV:
	if (SvFAKE(sv)) {
	    sv_unglob(sv);
	    break;
	}
	/* FALL THROUGH */
    case SVt_PVAV:
    case SVt_PVHV:
    case SVt_PVCV:
    case SVt_PVFM:
    case SVt_PVIO:
	{
	    dTHR;
	    croak("Can't coerce %s to number in %s", sv_reftype(sv,0),
		  op_name[op->op_type]);
	}
    }
    SvNVX(sv) = num;
    (void)SvNOK_only(sv);			/* validate number */
    SvTAINT(sv);
}

static void
not_a_number(SV *sv)
{
    dTHR;
    char tmpbuf[64];
    char *d = tmpbuf;
    char *s;
    char *limit = tmpbuf + sizeof(tmpbuf) - 8;
                  /* each *s can expand to 4 chars + "...\0",
                     i.e. need room for 8 chars */

    for (s = SvPVX(sv); *s && d < limit; s++) {
	int ch = *s & 0xFF;
	if (ch & 128 && !isPRINT_LC(ch)) {
	    *d++ = 'M';
	    *d++ = '-';
	    ch &= 127;
	}
	if (ch == '\n') {
	    *d++ = '\\';
	    *d++ = 'n';
	}
	else if (ch == '\r') {
	    *d++ = '\\';
	    *d++ = 'r';
	}
	else if (ch == '\f') {
	    *d++ = '\\';
	    *d++ = 'f';
	}
	else if (ch == '\\') {
	    *d++ = '\\';
	    *d++ = '\\';
	}
	else if (isPRINT_LC(ch))
	    *d++ = ch;
	else {
	    *d++ = '^';
	    *d++ = toCTRL(ch);
	}
    }
    if (*s) {
	*d++ = '.';
	*d++ = '.';
	*d++ = '.';
    }
    *d = '\0';

    if (op)
	warn("Argument \"%s\" isn't numeric in %s", tmpbuf,
		op_name[op->op_type]);
    else
	warn("Argument \"%s\" isn't numeric", tmpbuf);
}

IV
sv_2iv(register SV *sv)
{
    if (!sv)
	return 0;
    if (SvGMAGICAL(sv)) {
	mg_get(sv);
	if (SvIOKp(sv))
	    return SvIVX(sv);
	if (SvNOKp(sv)) {
	    if (SvNVX(sv) < 0.0)
		return I_V(SvNVX(sv));
	    else
		return (IV) U_V(SvNVX(sv));
	}
	if (SvPOKp(sv) && SvLEN(sv))
	    return asIV(sv);
	if (!SvROK(sv)) {
	    if (dowarn && !(SvFLAGS(sv) & SVs_PADTMP)) {
		dTHR;
		if (!localizing)
		    warn(warn_uninit);
	    }
	    return 0;
	}
    }
    if (SvTHINKFIRST(sv)) {
	if (SvROK(sv)) {
#ifdef OVERLOAD
	  SV* tmpstr;
	  if (SvAMAGIC(sv) && (tmpstr=AMG_CALLun(sv, numer)))
	    return SvIV(tmpstr);
#endif /* OVERLOAD */
	  return (IV)SvRV(sv);
	}
	if (SvREADONLY(sv)) {
	    if (SvNOKp(sv)) {
		if (SvNVX(sv) < 0.0)
		    return I_V(SvNVX(sv));
		else
		    return (IV) U_V(SvNVX(sv));
	    }
	    if (SvPOKp(sv) && SvLEN(sv))
		return asIV(sv);
	    if (dowarn)
		warn(warn_uninit);
	    return 0;
	}
    }
    switch (SvTYPE(sv)) {
    case SVt_NULL:
	sv_upgrade(sv, SVt_IV);
	break;
    case SVt_PV:
	sv_upgrade(sv, SVt_PVIV);
	break;
    case SVt_NV:
	sv_upgrade(sv, SVt_PVNV);
	break;
    }
    if (SvNOKp(sv)) {
	(void)SvIOK_on(sv);
	if (SvNVX(sv) < 0.0)
	    SvIVX(sv) = I_V(SvNVX(sv));
	else
	    SvUVX(sv) = U_V(SvNVX(sv));
    }
    else if (SvPOKp(sv) && SvLEN(sv)) {
	(void)SvIOK_on(sv);
	SvIVX(sv) = asIV(sv);
    }
    else  {
	dTHR;
	if (dowarn && !localizing && !(SvFLAGS(sv) & SVs_PADTMP))
	    warn(warn_uninit);
	return 0;
    }
    DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%lx 2iv(%ld)\n",
	(unsigned long)sv,(long)SvIVX(sv)));
    return SvIVX(sv);
}

UV
sv_2uv(register SV *sv)
{
    if (!sv)
	return 0;
    if (SvGMAGICAL(sv)) {
	mg_get(sv);
	if (SvIOKp(sv))
	    return SvUVX(sv);
	if (SvNOKp(sv))
	    return U_V(SvNVX(sv));
	if (SvPOKp(sv) && SvLEN(sv))
	    return asUV(sv);
	if (!SvROK(sv)) {
	    if (dowarn && !(SvFLAGS(sv) & SVs_PADTMP)) {
		dTHR;
		if (!localizing)
		    warn(warn_uninit);
	    }
	    return 0;
	}
    }
    if (SvTHINKFIRST(sv)) {
	if (SvROK(sv)) {
#ifdef OVERLOAD
	  SV* tmpstr;
	  if (SvAMAGIC(sv) && (tmpstr=AMG_CALLun(sv, numer)))
	    return SvUV(tmpstr);
#endif /* OVERLOAD */
	  return (UV)SvRV(sv);
	}
	if (SvREADONLY(sv)) {
	    if (SvNOKp(sv)) {
		return U_V(SvNVX(sv));
	    }
	    if (SvPOKp(sv) && SvLEN(sv))
		return asUV(sv);
	    if (dowarn)
		warn(warn_uninit);
	    return 0;
	}
    }
    switch (SvTYPE(sv)) {
    case SVt_NULL:
	sv_upgrade(sv, SVt_IV);
	break;
    case SVt_PV:
	sv_upgrade(sv, SVt_PVIV);
	break;
    case SVt_NV:
	sv_upgrade(sv, SVt_PVNV);
	break;
    }
    if (SvNOKp(sv)) {
	(void)SvIOK_on(sv);
	SvUVX(sv) = U_V(SvNVX(sv));
    }
    else if (SvPOKp(sv) && SvLEN(sv)) {
	(void)SvIOK_on(sv);
	SvUVX(sv) = asUV(sv);
    }
    else  {
	if (dowarn && !(SvFLAGS(sv) & SVs_PADTMP)) {
	    dTHR;
	    if (!localizing)
		warn(warn_uninit);
	}
	return 0;
    }
    DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%lx 2uv(%lu)\n",
	(unsigned long)sv,SvUVX(sv)));
    return SvUVX(sv);
}

double
sv_2nv(register SV *sv)
{
    if (!sv)
	return 0.0;
    if (SvGMAGICAL(sv)) {
	mg_get(sv);
	if (SvNOKp(sv))
	    return SvNVX(sv);
	if (SvPOKp(sv) && SvLEN(sv)) {
	    if (dowarn && !SvIOKp(sv) && !looks_like_number(sv))
		not_a_number(sv);
	    SET_NUMERIC_STANDARD();
	    return atof(SvPVX(sv));
	}
	if (SvIOKp(sv))
	    return (double)SvIVX(sv);
        if (!SvROK(sv)) {
	    if (dowarn && !(SvFLAGS(sv) & SVs_PADTMP)) {
		dTHR;
		if (!localizing)
		    warn(warn_uninit);
	    }
            return 0;
        }
    }
    if (SvTHINKFIRST(sv)) {
	if (SvROK(sv)) {
#ifdef OVERLOAD
	  SV* tmpstr;
	  if (SvAMAGIC(sv) && (tmpstr=AMG_CALLun(sv,numer)))
	    return SvNV(tmpstr);
#endif /* OVERLOAD */
	  return (double)(unsigned long)SvRV(sv);
	}
	if (SvREADONLY(sv)) {
	    if (SvPOKp(sv) && SvLEN(sv)) {
		if (dowarn && !SvIOKp(sv) && !looks_like_number(sv))
		    not_a_number(sv);
		SET_NUMERIC_STANDARD();
		return atof(SvPVX(sv));
	    }
	    if (SvIOKp(sv))
		return (double)SvIVX(sv);
	    if (dowarn)
		warn(warn_uninit);
	    return 0.0;
	}
    }
    if (SvTYPE(sv) < SVt_NV) {
	if (SvTYPE(sv) == SVt_IV)
	    sv_upgrade(sv, SVt_PVNV);
	else
	    sv_upgrade(sv, SVt_NV);
	DEBUG_c(SET_NUMERIC_STANDARD());
	DEBUG_c(PerlIO_printf(Perl_debug_log,
			      "0x%lx num(%g)\n",(unsigned long)sv,SvNVX(sv)));
    }
    else if (SvTYPE(sv) < SVt_PVNV)
	sv_upgrade(sv, SVt_PVNV);
    if (SvIOKp(sv) &&
	    (!SvPOKp(sv) || !strchr(SvPVX(sv),'.') || !looks_like_number(sv)))
    {
	SvNVX(sv) = (double)SvIVX(sv);
    }
    else if (SvPOKp(sv) && SvLEN(sv)) {
	if (dowarn && !SvIOKp(sv) && !looks_like_number(sv))
	    not_a_number(sv);
	SET_NUMERIC_STANDARD();
	SvNVX(sv) = atof(SvPVX(sv));
    }
    else  {
	dTHR;
	if (dowarn && !localizing && !(SvFLAGS(sv) & SVs_PADTMP))
	    warn(warn_uninit);
	return 0.0;
    }
    SvNOK_on(sv);
    DEBUG_c(SET_NUMERIC_STANDARD());
    DEBUG_c(PerlIO_printf(Perl_debug_log,
			  "0x%lx 2nv(%g)\n",(unsigned long)sv,SvNVX(sv)));
    return SvNVX(sv);
}

static IV
asIV(SV *sv)
{
    I32 numtype = looks_like_number(sv);
    double d;

    if (numtype == 1)
	return atol(SvPVX(sv));
    if (!numtype && dowarn)
	not_a_number(sv);
    SET_NUMERIC_STANDARD();
    d = atof(SvPVX(sv));
    if (d < 0.0)
	return I_V(d);
    else
	return (IV) U_V(d);
}

static UV
asUV(SV *sv)
{
    I32 numtype = looks_like_number(sv);

#ifdef HAS_STRTOUL
    if (numtype == 1)
	return strtoul(SvPVX(sv), Null(char**), 10);
#endif
    if (!numtype && dowarn)
	not_a_number(sv);
    SET_NUMERIC_STANDARD();
    return U_V(atof(SvPVX(sv)));
}

I32
looks_like_number(SV *sv)
{
    register char *s;
    register char *send;
    register char *sbegin;
    I32 numtype;
    STRLEN len;

    if (SvPOK(sv)) {
	sbegin = SvPVX(sv); 
	len = SvCUR(sv);
    }
    else if (SvPOKp(sv))
	sbegin = SvPV(sv, len);
    else
	return 1;
    send = sbegin + len;

    s = sbegin;
    while (isSPACE(*s))
	s++;
    if (*s == '+' || *s == '-')
	s++;

    /* next must be digit or '.' */
    if (isDIGIT(*s)) {
        do {
	    s++;
        } while (isDIGIT(*s));
        if (*s == '.') {
	    s++;
            while (isDIGIT(*s))  /* optional digits after "." */
                s++;
        }
    }
    else if (*s == '.') {
        s++;
        /* no digits before '.' means we need digits after it */
        if (isDIGIT(*s)) {
	    do {
	        s++;
            } while (isDIGIT(*s));
        }
        else
	    return 0;
    }
    else
        return 0;

    /*
     * we return 1 if the number can be converted to _integer_ with atol()
     * and 2 if you need (int)atof().
     */
    numtype = 1;

    /* we can have an optional exponent part */
    if (*s == 'e' || *s == 'E') {
	numtype = 2;
	s++;
	if (*s == '+' || *s == '-')
	    s++;
        if (isDIGIT(*s)) {
            do {
                s++;
            } while (isDIGIT(*s));
        }
        else
            return 0;
    }
    while (isSPACE(*s))
	s++;
    if (s >= send)
	return numtype;
    if (len == 10 && memEQ(sbegin, "0 but true", 10))
	return 1;
    return 0;
}

char *
sv_2pv(register SV *sv, STRLEN *lp)
{
    register char *s;
    int olderrno;
    SV *tsv;
    char tmpbuf[64];	/* Must fit sprintf/Gconvert of longest IV/NV */

    if (!sv) {
	*lp = 0;
	return "";
    }
    if (SvGMAGICAL(sv)) {
	mg_get(sv);
	if (SvPOKp(sv)) {
	    *lp = SvCUR(sv);
	    return SvPVX(sv);
	}
	if (SvIOKp(sv)) {
	    (void)sprintf(tmpbuf,"%ld",(long)SvIVX(sv));
	    tsv = Nullsv;
	    goto tokensave;
	}
	if (SvNOKp(sv)) {
	    SET_NUMERIC_STANDARD();
	    Gconvert(SvNVX(sv), DBL_DIG, 0, tmpbuf);
	    tsv = Nullsv;
	    goto tokensave;
	}
        if (!SvROK(sv)) {
	    if (dowarn && !(SvFLAGS(sv) & SVs_PADTMP)) {
		dTHR;
		if (!localizing)
		    warn(warn_uninit);
	    }
            *lp = 0;
            return "";
        }
    }
    if (SvTHINKFIRST(sv)) {
	if (SvROK(sv)) {
#ifdef OVERLOAD
	    SV* tmpstr;
	    if (SvAMAGIC(sv) && (tmpstr=AMG_CALLun(sv,string)))
	      return SvPV(tmpstr,*lp);
#endif /* OVERLOAD */
	    sv = (SV*)SvRV(sv);
	    if (!sv)
		s = "NULLREF";
	    else {
		switch (SvTYPE(sv)) {
		case SVt_NULL:
		case SVt_IV:
		case SVt_NV:
		case SVt_RV:
		case SVt_PV:
		case SVt_PVIV:
		case SVt_PVNV:
		case SVt_PVBM:
		case SVt_PVMG:	s = "SCALAR";			break;
		case SVt_PVLV:	s = "LVALUE";			break;
		case SVt_PVAV:	s = "ARRAY";			break;
		case SVt_PVHV:	s = "HASH";			break;
		case SVt_PVCV:	s = "CODE";			break;
		case SVt_PVGV:	s = "GLOB";			break;
		case SVt_PVFM:	s = "FORMATLINE";		break;
		case SVt_PVIO:	s = "IO";			break;
		default:	s = "UNKNOWN";			break;
		}
		tsv = NEWSV(0,0);
		if (SvOBJECT(sv))
		    sv_setpvf(tsv, "%s=%s", HvNAME(SvSTASH(sv)), s);
		else
		    sv_setpv(tsv, s);
		sv_catpvf(tsv, "(0x%lx)", (unsigned long)sv);
		goto tokensaveref;
	    }
	    *lp = strlen(s);
	    return s;
	}
	if (SvREADONLY(sv)) {
	    if (SvNOKp(sv)) {
		SET_NUMERIC_STANDARD();
		Gconvert(SvNVX(sv), DBL_DIG, 0, tmpbuf);
		tsv = Nullsv;
		goto tokensave;
	    }
	    if (SvIOKp(sv)) {
		(void)sprintf(tmpbuf,"%ld",(long)SvIVX(sv));
		tsv = Nullsv;
		goto tokensave;
	    }
	    if (dowarn)
		warn(warn_uninit);
	    *lp = 0;
	    return "";
	}
    }
    if (!SvUPGRADE(sv, SVt_PV))
	return 0;
    if (SvNOKp(sv)) {
	if (SvTYPE(sv) < SVt_PVNV)
	    sv_upgrade(sv, SVt_PVNV);
	SvGROW(sv, 28);
	s = SvPVX(sv);
	olderrno = errno;	/* some Xenix systems wipe out errno here */
#ifdef apollo
	if (SvNVX(sv) == 0.0)
	    (void)strcpy(s,"0");
	else
#endif /*apollo*/
	{
	    SET_NUMERIC_STANDARD();
	    Gconvert(SvNVX(sv), DBL_DIG, 0, s);
	}
	errno = olderrno;
#ifdef FIXNEGATIVEZERO
        if (*s == '-' && s[1] == '0' && !s[2])
	    strcpy(s,"0");
#endif
	while (*s) s++;
#ifdef hcx
	if (s[-1] == '.')
	    *--s = '\0';
#endif
    }
    else if (SvIOKp(sv)) {
	U32 oldIOK = SvIOK(sv);
	if (SvTYPE(sv) < SVt_PVIV)
	    sv_upgrade(sv, SVt_PVIV);
	olderrno = errno;	/* some Xenix systems wipe out errno here */
	sv_setpviv(sv, SvIVX(sv));
	errno = olderrno;
	s = SvEND(sv);
	if (oldIOK)
	    SvIOK_on(sv);
	else
	    SvIOKp_on(sv);
    }
    else {
	dTHR;
	if (dowarn && !localizing && !(SvFLAGS(sv) & SVs_PADTMP))
	    warn(warn_uninit);
	*lp = 0;
	return "";
    }
    *lp = s - SvPVX(sv);
    SvCUR_set(sv, *lp);
    SvPOK_on(sv);
    DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%lx 2pv(%s)\n",(unsigned long)sv,SvPVX(sv)));
    return SvPVX(sv);

  tokensave:
    if (SvROK(sv)) {	/* XXX Skip this when sv_pvn_force calls */
	/* Sneaky stuff here */

      tokensaveref:
	if (!tsv)
	    tsv = newSVpv(tmpbuf, 0);
	sv_2mortal(tsv);
	*lp = SvCUR(tsv);
	return SvPVX(tsv);
    }
    else {
	STRLEN len;
	char *t;

	if (tsv) {
	    sv_2mortal(tsv);
	    t = SvPVX(tsv);
	    len = SvCUR(tsv);
	}
	else {
	    t = tmpbuf;
	    len = strlen(tmpbuf);
	}
#ifdef FIXNEGATIVEZERO
	if (len == 2 && t[0] == '-' && t[1] == '0') {
	    t = "0";
	    len = 1;
	}
#endif
	(void)SvUPGRADE(sv, SVt_PV);
	*lp = len;
	s = SvGROW(sv, len + 1);
	SvCUR_set(sv, len);
	(void)strcpy(s, t);
	SvPOKp_on(sv);
	return s;
    }
}

/* This function is only called on magical items */
bool
sv_2bool(register SV *sv)
{
    if (SvGMAGICAL(sv))
	mg_get(sv);

    if (!SvOK(sv))
	return 0;
    if (SvROK(sv)) {
#ifdef OVERLOAD
      {
	dTHR;
	SV* tmpsv;
	if (SvAMAGIC(sv) && (tmpsv = AMG_CALLun(sv,bool_)))
	  return SvTRUE(tmpsv);
      }
#endif /* OVERLOAD */
      return SvRV(sv) != 0;
    }
    if (SvPOKp(sv)) {
	register XPV* Xpvtmp;
	if ((Xpvtmp = (XPV*)SvANY(sv)) &&
		(*Xpvtmp->xpv_pv > '0' ||
		Xpvtmp->xpv_cur > 1 ||
		(Xpvtmp->xpv_cur && *Xpvtmp->xpv_pv != '0')))
	    return 1;
	else
	    return 0;
    }
    else {
	if (SvIOKp(sv))
	    return SvIVX(sv) != 0;
	else {
	    if (SvNOKp(sv))
		return SvNVX(sv) != 0.0;
	    else
		return FALSE;
	}
    }
}

/* Note: sv_setsv() should not be called with a source string that needs
 * to be reused, since it may destroy the source string if it is marked
 * as temporary.
 */

void
sv_setsv(SV *dstr, register SV *sstr)
{
    dTHR;
    register U32 sflags;
    register int dtype;
    register int stype;

    if (sstr == dstr)
	return;
    sv_check_thinkfirst(dstr);
    if (!sstr)
	sstr = &sv_undef;
    stype = SvTYPE(sstr);
    dtype = SvTYPE(dstr);

    if (dtype == SVt_PVGV && (SvFLAGS(dstr) & SVf_FAKE)) {
        sv_unglob(dstr);     /* so fake GLOB won't perpetuate */
	sv_setpvn(dstr, "", 0);
        (void)SvPOK_only(dstr);
        dtype = SvTYPE(dstr);
    }

#ifdef OVERLOAD
    SvAMAGIC_off(dstr);
#endif /* OVERLOAD */
    /* There's a lot of redundancy below but we're going for speed here */

    switch (stype) {
    case SVt_NULL:
	(void)SvOK_off(dstr);
	return;
    case SVt_IV:
	if (dtype != SVt_IV && dtype < SVt_PVIV) {
	    if (dtype < SVt_IV)
		sv_upgrade(dstr, SVt_IV);
	    else if (dtype == SVt_NV)
		sv_upgrade(dstr, SVt_PVNV);
	    else
		sv_upgrade(dstr, SVt_PVIV);
	}
	break;
    case SVt_NV:
	if (dtype != SVt_NV && dtype < SVt_PVNV) {
	    if (dtype < SVt_NV)
		sv_upgrade(dstr, SVt_NV);
	    else
		sv_upgrade(dstr, SVt_PVNV);
	}
	break;
    case SVt_RV:
	if (dtype < SVt_RV)
	    sv_upgrade(dstr, SVt_RV);
	else if (dtype == SVt_PVGV &&
		 SvTYPE(SvRV(sstr)) == SVt_PVGV) {
	    sstr = SvRV(sstr);
	    if (sstr == dstr) {
		if (curcop->cop_stash != GvSTASH(dstr))
		    GvIMPORTED_on(dstr);
		GvMULTI_on(dstr);
		return;
	    }
	    goto glob_assign;
	}
	break;
    case SVt_PV:
    case SVt_PVFM:
	if (dtype < SVt_PV)
	    sv_upgrade(dstr, SVt_PV);
	break;
    case SVt_PVIV:
	if (dtype < SVt_PVIV)
	    sv_upgrade(dstr, SVt_PVIV);
	break;
    case SVt_PVNV:
	if (dtype < SVt_PVNV)
	    sv_upgrade(dstr, SVt_PVNV);
	break;

    case SVt_PVAV:
    case SVt_PVHV:
    case SVt_PVCV:
    case SVt_PVIO:
	if (op)
	    croak("Bizarre copy of %s in %s", sv_reftype(sstr, 0),
		op_name[op->op_type]);
	else
	    croak("Bizarre copy of %s", sv_reftype(sstr, 0));
	break;

    case SVt_PVGV:
	if (dtype <= SVt_PVGV) {
  glob_assign:
	    if (dtype != SVt_PVGV) {
		char *name = GvNAME(sstr);
		STRLEN len = GvNAMELEN(sstr);
		sv_upgrade(dstr, SVt_PVGV);
		sv_magic(dstr, dstr, '*', name, len);
		GvSTASH(dstr) = GvSTASH(sstr);
		GvNAME(dstr) = savepvn(name, len);
		GvNAMELEN(dstr) = len;
		SvFAKE_on(dstr);	/* can coerce to non-glob */
	    }
	    /* ahem, death to those who redefine active sort subs */
	    else if (curstack == sortstack
		     && GvCV(dstr) && sortcop == CvSTART(GvCV(dstr)))
		croak("Can't redefine active sort subroutine %s",
		      GvNAME(dstr));
	    (void)SvOK_off(dstr);
	    GvINTRO_off(dstr);		/* one-shot flag */
	    gp_free((GV*)dstr);
	    GvGP(dstr) = gp_ref(GvGP(sstr));
	    SvTAINT(dstr);
	    if (curcop->cop_stash != GvSTASH(dstr))
		GvIMPORTED_on(dstr);
	    GvMULTI_on(dstr);
	    return;
	}
	/* FALL THROUGH */

    default:
	if (SvGMAGICAL(sstr)) {
	    mg_get(sstr);
	    if (SvTYPE(sstr) != stype) {
		stype = SvTYPE(sstr);
		if (stype == SVt_PVGV && dtype <= SVt_PVGV)
		    goto glob_assign;
	    }
	}
	if (dtype < stype)
	    sv_upgrade(dstr, stype);
    }

    sflags = SvFLAGS(sstr);

    if (sflags & SVf_ROK) {
	if (dtype >= SVt_PV) {
	    if (dtype == SVt_PVGV) {
		dTHR;
		SV *sref = SvREFCNT_inc(SvRV(sstr));
		SV *dref = 0;
		int intro = GvINTRO(dstr);

		if (intro) {
		    GP *gp;
		    GvGP(dstr)->gp_refcnt--;
		    GvINTRO_off(dstr);	/* one-shot flag */
		    Newz(602,gp, 1, GP);
		    GvGP(dstr) = gp_ref(gp);
		    GvSV(dstr) = NEWSV(72,0);
		    GvLINE(dstr) = curcop->cop_line;
		    GvEGV(dstr) = (GV*)dstr;
		}
		GvMULTI_on(dstr);
		switch (SvTYPE(sref)) {
		case SVt_PVAV:
		    if (intro)
			SAVESPTR(GvAV(dstr));
		    else
			dref = (SV*)GvAV(dstr);
		    GvAV(dstr) = (AV*)sref;
		    if (curcop->cop_stash != GvSTASH(dstr))
			GvIMPORTED_AV_on(dstr);
		    break;
		case SVt_PVHV:
		    if (intro)
			SAVESPTR(GvHV(dstr));
		    else
			dref = (SV*)GvHV(dstr);
		    GvHV(dstr) = (HV*)sref;
		    if (curcop->cop_stash != GvSTASH(dstr))
			GvIMPORTED_HV_on(dstr);
		    break;
		case SVt_PVCV:
		    if (intro) {
			if (GvCVGEN(dstr) && GvCV(dstr) != (CV*)sref) {
			    SvREFCNT_dec(GvCV(dstr));
			    GvCV(dstr) = Nullcv;
			    GvCVGEN(dstr) = 0; /* Switch off cacheness. */
			    sub_generation++;
			}
			SAVESPTR(GvCV(dstr));
		    }
		    else
			dref = (SV*)GvCV(dstr);
		    if (GvCV(dstr) != (CV*)sref) {
			CV* cv = GvCV(dstr);
			if (cv) {
			    if (!GvCVGEN((GV*)dstr) &&
				(CvROOT(cv) || CvXSUB(cv)))
			    {
				/* ahem, death to those who redefine
				 * active sort subs */
				if (curstack == sortstack &&
				      sortcop == CvSTART(cv))
				    croak(
				    "Can't redefine active sort subroutine %s",
					  GvENAME((GV*)dstr));
				if (cv_const_sv(cv))
				    warn("Constant subroutine %s redefined",
					 GvENAME((GV*)dstr));
				else if (dowarn)
				    warn("Subroutine %s redefined",
					 GvENAME((GV*)dstr));
			    }
			    cv_ckproto(cv, (GV*)dstr,
				       SvPOK(sref) ? SvPVX(sref) : Nullch);
			}
			GvCV(dstr) = (CV*)sref;
			GvCVGEN(dstr) = 0; /* Switch off cacheness. */
			GvASSUMECV_on(dstr);
			sub_generation++;
		    }
		    if (curcop->cop_stash != GvSTASH(dstr))
			GvIMPORTED_CV_on(dstr);
		    break;
		case SVt_PVIO:
		    if (intro)
			SAVESPTR(GvIOp(dstr));
		    else
			dref = (SV*)GvIOp(dstr);
		    GvIOp(dstr) = (IO*)sref;
		    break;
		default:
		    if (intro)
			SAVESPTR(GvSV(dstr));
		    else
			dref = (SV*)GvSV(dstr);
		    GvSV(dstr) = sref;
		    if (curcop->cop_stash != GvSTASH(dstr))
			GvIMPORTED_SV_on(dstr);
		    break;
		}
		if (dref)
		    SvREFCNT_dec(dref);
		if (intro)
		    SAVEFREESV(sref);
		SvTAINT(dstr);
		return;
	    }
	    if (SvPVX(dstr)) {
		(void)SvOOK_off(dstr);		/* backoff */
		Safefree(SvPVX(dstr));
		SvLEN(dstr)=SvCUR(dstr)=0;
	    }
	}
	(void)SvOK_off(dstr);
	SvRV(dstr) = SvREFCNT_inc(SvRV(sstr));
	SvROK_on(dstr);
	if (sflags & SVp_NOK) {
	    SvNOK_on(dstr);
	    SvNVX(dstr) = SvNVX(sstr);
	}
	if (sflags & SVp_IOK) {
	    (void)SvIOK_on(dstr);
	    SvIVX(dstr) = SvIVX(sstr);
	}
#ifdef OVERLOAD
	if (SvAMAGIC(sstr)) {
	    SvAMAGIC_on(dstr);
	}
#endif /* OVERLOAD */
    }
    else if (sflags & SVp_POK) {

	/*
	 * Check to see if we can just swipe the string.  If so, it's a
	 * possible small lose on short strings, but a big win on long ones.
	 * It might even be a win on short strings if SvPVX(dstr)
	 * has to be allocated and SvPVX(sstr) has to be freed.
	 */

	if (SvTEMP(sstr) &&		/* slated for free anyway? */
	    SvREFCNT(sstr) == 1 && 	/* and no other references to it? */
	    !(sflags & SVf_OOK)) 	/* and not involved in OOK hack? */
	{
	    if (SvPVX(dstr)) {		/* we know that dtype >= SVt_PV */
		if (SvOOK(dstr)) {
		    SvFLAGS(dstr) &= ~SVf_OOK;
		    Safefree(SvPVX(dstr) - SvIVX(dstr));
		}
		else
		    Safefree(SvPVX(dstr));
	    }
	    (void)SvPOK_only(dstr);
	    SvPV_set(dstr, SvPVX(sstr));
	    SvLEN_set(dstr, SvLEN(sstr));
	    SvCUR_set(dstr, SvCUR(sstr));
	    SvTEMP_off(dstr);
	    (void)SvOK_off(sstr);
	    SvPV_set(sstr, Nullch);
	    SvLEN_set(sstr, 0);
	    SvCUR_set(sstr, 0);
	    SvTEMP_off(sstr);
	}
	else {					/* have to copy actual string */
	    STRLEN len = SvCUR(sstr);

	    SvGROW(dstr, len + 1);		/* inlined from sv_setpvn */
	    Move(SvPVX(sstr),SvPVX(dstr),len,char);
	    SvCUR_set(dstr, len);
	    *SvEND(dstr) = '\0';
	    (void)SvPOK_only(dstr);
	}
	/*SUPPRESS 560*/
	if (sflags & SVp_NOK) {
	    SvNOK_on(dstr);
	    SvNVX(dstr) = SvNVX(sstr);
	}
	if (sflags & SVp_IOK) {
	    (void)SvIOK_on(dstr);
	    SvIVX(dstr) = SvIVX(sstr);
	}
    }
    else if (sflags & SVp_NOK) {
	SvNVX(dstr) = SvNVX(sstr);
	(void)SvNOK_only(dstr);
	if (SvIOK(sstr)) {
	    (void)SvIOK_on(dstr);
	    SvIVX(dstr) = SvIVX(sstr);
	}
    }
    else if (sflags & SVp_IOK) {
	(void)SvIOK_only(dstr);
	SvIVX(dstr) = SvIVX(sstr);
    }
    else {
	(void)SvOK_off(dstr);
    }
    SvTAINT(dstr);
}

void
sv_setpvn(register SV *sv, register const char *ptr, register STRLEN len)
{
    assert(len >= 0);  /* STRLEN is probably unsigned, so this may
			  elicit a warning, but it won't hurt. */
    sv_check_thinkfirst(sv);
    if (!ptr) {
	(void)SvOK_off(sv);
	return;
    }
    if (SvTYPE(sv) >= SVt_PV) {
	if (SvFAKE(sv) && SvTYPE(sv) == SVt_PVGV)
	    sv_unglob(sv);
    }
    else if (!sv_upgrade(sv, SVt_PV))
	return;
    SvGROW(sv, len + 1);
    Move(ptr,SvPVX(sv),len,char);
    SvCUR_set(sv, len);
    *SvEND(sv) = '\0';
    (void)SvPOK_only(sv);		/* validate pointer */
    SvTAINT(sv);
}

void
sv_setpv(register SV *sv, register const char *ptr)
{
    register STRLEN len;

    sv_check_thinkfirst(sv);
    if (!ptr) {
	(void)SvOK_off(sv);
	return;
    }
    len = strlen(ptr);
    if (SvTYPE(sv) >= SVt_PV) {
	if (SvFAKE(sv) && SvTYPE(sv) == SVt_PVGV)
	    sv_unglob(sv);
    }
    else if (!sv_upgrade(sv, SVt_PV))
	return;
    SvGROW(sv, len + 1);
    Move(ptr,SvPVX(sv),len+1,char);
    SvCUR_set(sv, len);
    (void)SvPOK_only(sv);		/* validate pointer */
    SvTAINT(sv);
}

void
sv_usepvn(register SV *sv, register char *ptr, register STRLEN len)
{
    sv_check_thinkfirst(sv);
    if (!SvUPGRADE(sv, SVt_PV))
	return;
    if (!ptr) {
	(void)SvOK_off(sv);
	return;
    }
    if (SvPVX(sv))
	Safefree(SvPVX(sv));
    Renew(ptr, len+1, char);
    SvPVX(sv) = ptr;
    SvCUR_set(sv, len);
    SvLEN_set(sv, len+1);
    *SvEND(sv) = '\0';
    (void)SvPOK_only(sv);		/* validate pointer */
    SvTAINT(sv);
}

static void
sv_check_thinkfirst(register SV *sv)
{
    if (SvTHINKFIRST(sv)) {
	if (SvREADONLY(sv)) {
	    dTHR;
	    if (curcop != &compiling)
		croak(no_modify);
	}
	if (SvROK(sv))
	    sv_unref(sv);
    }
}
    
void
sv_chop(register SV *sv, register char *ptr)	/* like set but assuming ptr is in sv */
                
                   
{
    register STRLEN delta;

    if (!ptr || !SvPOKp(sv))
	return;
    sv_check_thinkfirst(sv);
    if (SvTYPE(sv) < SVt_PVIV)
	sv_upgrade(sv,SVt_PVIV);

    if (!SvOOK(sv)) {
	SvIVX(sv) = 0;
	SvFLAGS(sv) |= SVf_OOK;
    }
    SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK|SVp_IOK|SVp_NOK);
    delta = ptr - SvPVX(sv);
    SvLEN(sv) -= delta;
    SvCUR(sv) -= delta;
    SvPVX(sv) += delta;
    SvIVX(sv) += delta;
}

void
sv_catpvn(register SV *sv, register char *ptr, register STRLEN len)
{
    STRLEN tlen;
    char *junk;

    junk = SvPV_force(sv, tlen);
    SvGROW(sv, tlen + len + 1);
    if (ptr == junk)
	ptr = SvPVX(sv);
    Move(ptr,SvPVX(sv)+tlen,len,char);
    SvCUR(sv) += len;
    *SvEND(sv) = '\0';
    (void)SvPOK_only(sv);		/* validate pointer */
    SvTAINT(sv);
}

void
sv_catsv(SV *dstr, register SV *sstr)
{
    char *s;
    STRLEN len;
    if (!sstr)
	return;
    if (s = SvPV(sstr, len))
	sv_catpvn(dstr,s,len);
}

void
sv_catpv(register SV *sv, register char *ptr)
{
    register STRLEN len;
    STRLEN tlen;
    char *junk;

    if (!ptr)
	return;
    junk = SvPV_force(sv, tlen);
    len = strlen(ptr);
    SvGROW(sv, tlen + len + 1);
    if (ptr == junk)
	ptr = SvPVX(sv);
    Move(ptr,SvPVX(sv)+tlen,len+1,char);
    SvCUR(sv) += len;
    (void)SvPOK_only(sv);		/* validate pointer */
    SvTAINT(sv);
}

SV *
#ifdef LEAKTEST
newSV(x,len)
I32 x;
#else
newSV(STRLEN len)
#endif
           
{
    register SV *sv;
    
    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
    if (len) {
	sv_upgrade(sv, SVt_PV);
	SvGROW(sv, len + 1);
    }
    return sv;
}

/* name is assumed to contain an SV* if (name && namelen == HEf_SVKEY) */

void
sv_magic(register SV *sv, SV *obj, int how, char *name, I32 namlen)
{
    MAGIC* mg;
    
    if (SvREADONLY(sv)) {
	dTHR;
	if (curcop != &compiling && !strchr("gBf", how))
	    croak(no_modify);
    }
    if (SvMAGICAL(sv) || (how == 't' && SvTYPE(sv) >= SVt_PVMG)) {
	if (SvMAGIC(sv) && (mg = mg_find(sv, how))) {
	    if (how == 't')
		mg->mg_len |= 1;
	    return;
	}
    }
    else {
	if (!SvUPGRADE(sv, SVt_PVMG))
	    return;
    }
    Newz(702,mg, 1, MAGIC);
    mg->mg_moremagic = SvMAGIC(sv);

    SvMAGIC(sv) = mg;
    if (!obj || obj == sv || how == '#' || how == 'r')
	mg->mg_obj = obj;
    else {
	dTHR;
	mg->mg_obj = SvREFCNT_inc(obj);
	mg->mg_flags |= MGf_REFCOUNTED;
    }
    mg->mg_type = how;
    mg->mg_len = namlen;
    if (name)
	if (namlen >= 0)
	    mg->mg_ptr = savepvn(name, namlen);
	else if (namlen == HEf_SVKEY)
	    mg->mg_ptr = (char*)SvREFCNT_inc((SV*)name);
    
    switch (how) {
    case 0:
	mg->mg_virtual = &vtbl_sv;
	break;
#ifdef OVERLOAD
    case 'A':
        mg->mg_virtual = &vtbl_amagic;
        break;
    case 'a':
        mg->mg_virtual = &vtbl_amagicelem;
        break;
    case 'c':
        mg->mg_virtual = 0;
        break;
#endif /* OVERLOAD */
    case 'B':
	mg->mg_virtual = &vtbl_bm;
	break;
    case 'E':
	mg->mg_virtual = &vtbl_env;
	break;
    case 'f':
	mg->mg_virtual = &vtbl_fm;
	break;
    case 'e':
	mg->mg_virtual = &vtbl_envelem;
	break;
    case 'g':
	mg->mg_virtual = &vtbl_mglob;
	break;
    case 'I':
	mg->mg_virtual = &vtbl_isa;
	break;
    case 'i':
	mg->mg_virtual = &vtbl_isaelem;
	break;
    case 'k':
	mg->mg_virtual = &vtbl_nkeys;
	break;
    case 'L':
	SvRMAGICAL_on(sv);
	mg->mg_virtual = 0;
	break;
    case 'l':
	mg->mg_virtual = &vtbl_dbline;
	break;
#ifdef USE_THREADS
    case 'm':
	mg->mg_virtual = &vtbl_mutex;
	break;
#endif /* USE_THREADS */
#ifdef USE_LOCALE_COLLATE
    case 'o':
        mg->mg_virtual = &vtbl_collxfrm;
        break;
#endif /* USE_LOCALE_COLLATE */
    case 'P':
	mg->mg_virtual = &vtbl_pack;
	break;
    case 'p':
    case 'q':
	mg->mg_virtual = &vtbl_packelem;
	break;
    case 'r':
	mg->mg_virtual = &vtbl_regexp;
	break;
    case 'S':
	mg->mg_virtual = &vtbl_sig;
	break;
    case 's':
	mg->mg_virtual = &vtbl_sigelem;
	break;
    case 't':
	mg->mg_virtual = &vtbl_taint;
	mg->mg_len = 1;
	break;
    case 'U':
	mg->mg_virtual = &vtbl_uvar;
	break;
    case 'v':
	mg->mg_virtual = &vtbl_vec;
	break;
    case 'x':
	mg->mg_virtual = &vtbl_substr;
	break;
    case 'y':
	mg->mg_virtual = &vtbl_defelem;
	break;
    case '*':
	mg->mg_virtual = &vtbl_glob;
	break;
    case '#':
	mg->mg_virtual = &vtbl_arylen;
	break;
    case '.':
	mg->mg_virtual = &vtbl_pos;
	break;
    case '~':	/* Reserved for use by extensions not perl internals.	*/
	/* Useful for attaching extension internal data to perl vars.	*/
	/* Note that multiple extensions may clash if magical scalars	*/
	/* etc holding private data from one are passed to another.	*/
	SvRMAGICAL_on(sv);
	break;
    default:
	croak("Don't know how to handle magic of type '%c'", how);
    }
    mg_magical(sv);
    if (SvGMAGICAL(sv))
	SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK|SVf_POK);
}

int
sv_unmagic(SV *sv, int type)
{
    MAGIC* mg;
    MAGIC** mgp;
    if (SvTYPE(sv) < SVt_PVMG || !SvMAGIC(sv))
	return 0;
    mgp = &SvMAGIC(sv);
    for (mg = *mgp; mg; mg = *mgp) {
	if (mg->mg_type == type) {
	    MGVTBL* vtbl = mg->mg_virtual;
	    *mgp = mg->mg_moremagic;
	    if (vtbl && vtbl->svt_free)
		(*vtbl->svt_free)(sv, mg);
	    if (mg->mg_ptr && mg->mg_type != 'g')
		if (mg->mg_len >= 0)
		    Safefree(mg->mg_ptr);
		else if (mg->mg_len == HEf_SVKEY)
		    SvREFCNT_dec((SV*)mg->mg_ptr);
	    if (mg->mg_flags & MGf_REFCOUNTED)
		SvREFCNT_dec(mg->mg_obj);
	    Safefree(mg);
	}
	else
	    mgp = &mg->mg_moremagic;
    }
    if (!SvMAGIC(sv)) {
	SvMAGICAL_off(sv);
	SvFLAGS(sv) |= (SvFLAGS(sv) & (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
    }

    return 0;
}

void
sv_insert(SV *bigstr, STRLEN offset, STRLEN len, char *little, STRLEN littlelen)
{
    register char *big;
    register char *mid;
    register char *midend;
    register char *bigend;
    register I32 i;

    if (!bigstr)
	croak("Can't modify non-existent substring");
    SvPV_force(bigstr, na);

    i = littlelen - len;
    if (i > 0) {			/* string might grow */
	big = SvGROW(bigstr, SvCUR(bigstr) + i + 1);
	mid = big + offset + len;
	midend = bigend = big + SvCUR(bigstr);
	bigend += i;
	*bigend = '\0';
	while (midend > mid)		/* shove everything down */
	    *--bigend = *--midend;
	Move(little,big+offset,littlelen,char);
	SvCUR(bigstr) += i;
	SvSETMAGIC(bigstr);
	return;
    }
    else if (i == 0) {
	Move(little,SvPVX(bigstr)+offset,len,char);
	SvSETMAGIC(bigstr);
	return;
    }

    big = SvPVX(bigstr);
    mid = big + offset;
    midend = mid + len;
    bigend = big + SvCUR(bigstr);

    if (midend > bigend)
	croak("panic: sv_insert");

    if (mid - big > bigend - midend) {	/* faster to shorten from end */
	if (littlelen) {
	    Move(little, mid, littlelen,char);
	    mid += littlelen;
	}
	i = bigend - midend;
	if (i > 0) {
	    Move(midend, mid, i,char);
	    mid += i;
	}
	*mid = '\0';
	SvCUR_set(bigstr, mid - big);
    }
    /*SUPPRESS 560*/
    else if (i = mid - big) {	/* faster from front */
	midend -= littlelen;
	mid = midend;
	sv_chop(bigstr,midend-i);
	big += i;
	while (i--)
	    *--midend = *--big;
	if (littlelen)
	    Move(little, mid, littlelen,char);
    }
    else if (littlelen) {
	midend -= littlelen;
	sv_chop(bigstr,midend);
	Move(little,midend,littlelen,char);
    }
    else {
	sv_chop(bigstr,midend);
    }
    SvSETMAGIC(bigstr);
}

/* make sv point to what nstr did */

void
sv_replace(register SV *sv, register SV *nsv)
{
    U32 refcnt = SvREFCNT(sv);
    sv_check_thinkfirst(sv);
    if (SvREFCNT(nsv) != 1)
	warn("Reference miscount in sv_replace()");
    if (SvMAGICAL(sv)) {
	if (SvMAGICAL(nsv))
	    mg_free(nsv);
	else
	    sv_upgrade(nsv, SVt_PVMG);
	SvMAGIC(nsv) = SvMAGIC(sv);
	SvFLAGS(nsv) |= SvMAGICAL(sv);
	SvMAGICAL_off(sv);
	SvMAGIC(sv) = 0;
    }
    SvREFCNT(sv) = 0;
    sv_clear(sv);
    assert(!SvREFCNT(sv));
    StructCopy(nsv,sv,SV);
    SvREFCNT(sv) = refcnt;
    SvFLAGS(nsv) |= SVTYPEMASK;		/* Mark as freed */
    del_SV(nsv);
}

void
sv_clear(register SV *sv)
{
    assert(sv);
    assert(SvREFCNT(sv) == 0);

    if (SvOBJECT(sv)) {
	dTHR;
	if (defstash) {		/* Still have a symbol table? */
	    djSP;
	    GV* destructor;

	    ENTER;
	    SAVEFREESV(SvSTASH(sv));

	    destructor = gv_fetchmethod(SvSTASH(sv), "DESTROY");
	    if (destructor) {
		SV ref;

		Zero(&ref, 1, SV);
		sv_upgrade(&ref, SVt_RV);
		SvRV(&ref) = SvREFCNT_inc(sv);
		SvROK_on(&ref);
		SvREFCNT(&ref) = 1;	/* Fake, but otherwise
					   creating+destructing a ref
					   leads to disaster. */

		EXTEND(SP, 2);
		PUSHMARK(SP);
		PUSHs(&ref);
		PUTBACK;
		perl_call_sv((SV*)GvCV(destructor),
			     G_DISCARD|G_EVAL|G_KEEPERR);
		del_XRV(SvANY(&ref));
		SvREFCNT(sv)--;
	    }

	    LEAVE;
	}
	else
	    SvREFCNT_dec(SvSTASH(sv));
	if (SvOBJECT(sv)) {
	    SvOBJECT_off(sv);	/* Curse the object. */
	    if (SvTYPE(sv) != SVt_PVIO)
		--sv_objcount;	/* XXX Might want something more general */
	}
	if (SvREFCNT(sv)) {
		if (in_clean_objs)
		    croak("DESTROY created new reference to dead object");
		/* DESTROY gave object new lease on life */
		return;
	}
    }
    if (SvTYPE(sv) >= SVt_PVMG && SvMAGIC(sv))
	mg_free(sv);
    switch (SvTYPE(sv)) {
    case SVt_PVIO:
	if (IoIFP(sv) != PerlIO_stdin() &&
	    IoIFP(sv) != PerlIO_stdout() &&
	    IoIFP(sv) != PerlIO_stderr())
	  io_close((IO*)sv);
	Safefree(IoTOP_NAME(sv));
	Safefree(IoFMT_NAME(sv));
	Safefree(IoBOTTOM_NAME(sv));
	/* FALL THROUGH */
    case SVt_PVBM:
	goto freescalar;
    case SVt_PVCV:
    case SVt_PVFM:
	cv_undef((CV*)sv);
	goto freescalar;
    case SVt_PVHV:
	hv_undef((HV*)sv);
	break;
    case SVt_PVAV:
	av_undef((AV*)sv);
	break;
    case SVt_PVGV:
	gp_free((GV*)sv);
	Safefree(GvNAME(sv));
	/* FALL THROUGH */
    case SVt_PVLV:
    case SVt_PVMG:
    case SVt_PVNV:
    case SVt_PVIV:
      freescalar:
	(void)SvOOK_off(sv);
	/* FALL THROUGH */
    case SVt_PV:
    case SVt_RV:
	if (SvROK(sv))
	    SvREFCNT_dec(SvRV(sv));
	else if (SvPVX(sv) && SvLEN(sv))
	    Safefree(SvPVX(sv));
	break;
/*
    case SVt_NV:
    case SVt_IV:
    case SVt_NULL:
	break;
*/
    }

    switch (SvTYPE(sv)) {
    case SVt_NULL:
	break;
    case SVt_IV:
	del_XIV(SvANY(sv));
	break;
    case SVt_NV:
	del_XNV(SvANY(sv));
	break;
    case SVt_RV:
	del_XRV(SvANY(sv));
	break;
    case SVt_PV:
	del_XPV(SvANY(sv));
	break;
    case SVt_PVIV:
	del_XPVIV(SvANY(sv));
	break;
    case SVt_PVNV:
	del_XPVNV(SvANY(sv));
	break;
    case SVt_PVMG:
	del_XPVMG(SvANY(sv));
	break;
    case SVt_PVLV:
	del_XPVLV(SvANY(sv));
	break;
    case SVt_PVAV:
	del_XPVAV(SvANY(sv));
	break;
    case SVt_PVHV:
	del_XPVHV(SvANY(sv));
	break;
    case SVt_PVCV:
	del_XPVCV(SvANY(sv));
	break;
    case SVt_PVGV:
	del_XPVGV(SvANY(sv));
	break;
    case SVt_PVBM:
	del_XPVBM(SvANY(sv));
	break;
    case SVt_PVFM:
	del_XPVFM(SvANY(sv));
	break;
    case SVt_PVIO:
	del_XPVIO(SvANY(sv));
	break;
    }
    SvFLAGS(sv) &= SVf_BREAK;
    SvFLAGS(sv) |= SVTYPEMASK;
}

SV *
sv_newref(SV *sv)
{
    if (sv)
	SvREFCNT(sv)++;
    return sv;
}

void
sv_free(SV *sv)
{
    if (!sv)
	return;
    if (SvREADONLY(sv)) {
	if (sv == &sv_undef || sv == &sv_yes || sv == &sv_no)
	    return;
    }
    if (SvREFCNT(sv) == 0) {
	if (SvFLAGS(sv) & SVf_BREAK)
	    return;
	if (in_clean_all) /* All is fair */
	    return;
	warn("Attempt to free unreferenced scalar");
	return;
    }
    if (--SvREFCNT(sv) > 0)
	return;
#ifdef DEBUGGING
    if (SvTEMP(sv)) {
	warn("Attempt to free temp prematurely: %s", SvPEEK(sv));
	return;
    }
#endif
    sv_clear(sv);
    if (! SvREFCNT(sv))
	del_SV(sv);
}

STRLEN
sv_len(register SV *sv)
{
    char *junk;
    STRLEN len;

    if (!sv)
	return 0;

    if (SvGMAGICAL(sv))
	len = mg_len(sv);
    else
	junk = SvPV(sv, len);
    return len;
}

I32
sv_eq(register SV *str1, register SV *str2)
{
    char *pv1;
    STRLEN cur1;
    char *pv2;
    STRLEN cur2;

    if (!str1) {
	pv1 = "";
	cur1 = 0;
    }
    else
	pv1 = SvPV(str1, cur1);

    if (!str2)
	return !cur1;
    else
	pv2 = SvPV(str2, cur2);

    if (cur1 != cur2)
	return 0;

    return memEQ(pv1, pv2, cur1);
}

I32
sv_cmp(register SV *str1, register SV *str2)
{
    STRLEN cur1 = 0;
    char *pv1 = str1 ? SvPV(str1, cur1) : (char *) NULL;
    STRLEN cur2 = 0;
    char *pv2 = str2 ? SvPV(str2, cur2) : (char *) NULL;
    I32 retval;

    if (!cur1)
	return cur2 ? -1 : 0;

    if (!cur2)
	return 1;

    retval = memcmp((void*)pv1, (void*)pv2, cur1 < cur2 ? cur1 : cur2);

    if (retval)
	return retval < 0 ? -1 : 1;

    if (cur1 == cur2)
	return 0;
    else
	return cur1 < cur2 ? -1 : 1;
}

I32
sv_cmp_locale(register SV *sv1, register SV *sv2)
{
#ifdef USE_LOCALE_COLLATE

    char *pv1, *pv2;
    STRLEN len1, len2;
    I32 retval;

    if (collation_standard)
	goto raw_compare;

    len1 = 0;
    pv1 = sv1 ? sv_collxfrm(sv1, &len1) : (char *) NULL;
    len2 = 0;
    pv2 = sv2 ? sv_collxfrm(sv2, &len2) : (char *) NULL;

    if (!pv1 || !len1) {
	if (pv2 && len2)
	    return -1;
	else
	    goto raw_compare;
    }
    else {
	if (!pv2 || !len2)
	    return 1;
    }

    retval = memcmp((void*)pv1, (void*)pv2, len1 < len2 ? len1 : len2);

    if (retval)
	return retval < 0 ? -1 : 1;

    /*
     * When the result of collation is equality, that doesn't mean
     * that there are no differences -- some locales exclude some
     * characters from consideration.  So to avoid false equalities,
     * we use the raw string as a tiebreaker.
     */

  raw_compare:
    /* FALL THROUGH */

#endif /* USE_LOCALE_COLLATE */

    return sv_cmp(sv1, sv2);
}

#ifdef USE_LOCALE_COLLATE
/*
 * Any scalar variable may carry an 'o' magic that contains the
 * scalar data of the variable transformed to such a format that
 * a normal memory comparison can be used to compare the data
 * according to the locale settings.
 */
char *
sv_collxfrm(SV *sv, STRLEN *nxp)
{
    MAGIC *mg;

    mg = SvMAGICAL(sv) ? mg_find(sv, 'o') : (MAGIC *) NULL;
    if (!mg || !mg->mg_ptr || *(U32*)mg->mg_ptr != collation_ix) {
	char *s, *xf;
	STRLEN len, xlen;

	if (mg)
	    Safefree(mg->mg_ptr);
	s = SvPV(sv, len);
	if ((xf = mem_collxfrm(s, len, &xlen))) {
	    if (SvREADONLY(sv)) {
		SAVEFREEPV(xf);
		*nxp = xlen;
		return xf + sizeof(collation_ix);
	    }
	    if (! mg) {
		sv_magic(sv, 0, 'o', 0, 0);
		mg = mg_find(sv, 'o');
		assert(mg);
	    }
	    mg->mg_ptr = xf;
	    mg->mg_len = xlen;
	}
	else {
	    if (mg) {
		mg->mg_ptr = NULL;
		mg->mg_len = -1;
	    }
	}
    }
    if (mg && mg->mg_ptr) {
	*nxp = mg->mg_len;
	return mg->mg_ptr + sizeof(collation_ix);
    }
    else {
	*nxp = 0;
	return NULL;
    }
}

#endif /* USE_LOCALE_COLLATE */

char *
sv_gets(register SV *sv, register FILE *fp, I32 append)
{
    dTHR;
    char *rsptr;
    STRLEN rslen;
    register STDCHAR rslast;
    register STDCHAR *bp;
    register I32 cnt;
    I32 i;

    sv_check_thinkfirst(sv);
    if (!SvUPGRADE(sv, SVt_PV))
	return 0;
    SvSCREAM_off(sv);

    if (RsSNARF(rs)) {
	rsptr = NULL;
	rslen = 0;
    }
    else if (RsPARA(rs)) {
	rsptr = "\n\n";
	rslen = 2;
    }
    else
	rsptr = SvPV(rs, rslen);
    rslast = rslen ? rsptr[rslen - 1] : '\0';

    if (RsPARA(rs)) {		/* have to do this both before and after */
	do {			/* to make sure file boundaries work right */
	    if (PerlIO_eof(fp))
		return 0;
	    i = PerlIO_getc(fp);
	    if (i != '\n') {
		if (i == -1)
		    return 0;
		PerlIO_ungetc(fp,i);
		break;
	    }
	} while (i != EOF);
    }

    /* See if we know enough about I/O mechanism to cheat it ! */

    /* This used to be #ifdef test - it is made run-time test for ease
       of abstracting out stdio interface. One call should be cheap 
       enough here - and may even be a macro allowing compile
       time optimization.
     */

    if (PerlIO_fast_gets(fp)) {

    /*
     * We're going to steal some values from the stdio struct
     * and put EVERYTHING in the innermost loop into registers.
     */
    register STDCHAR *ptr;
    STRLEN bpx;
    I32 shortbuffered;

#if defined(VMS) && defined(PERLIO_IS_STDIO)
    /* An ungetc()d char is handled separately from the regular
     * buffer, so we getc() it back out and stuff it in the buffer.
     */
    i = PerlIO_getc(fp);
    if (i == EOF) return 0;
    *(--((*fp)->_ptr)) = (unsigned char) i;
    (*fp)->_cnt++;
#endif

    /* Here is some breathtakingly efficient cheating */

    cnt = PerlIO_get_cnt(fp);			/* get count into register */
    (void)SvPOK_only(sv);		/* validate pointer */
    if (SvLEN(sv) - append <= cnt + 1) { /* make sure we have the room */
	if (cnt > 80 && SvLEN(sv) > append) {
	    shortbuffered = cnt - SvLEN(sv) + append + 1;
	    cnt -= shortbuffered;
	}
	else {
	    shortbuffered = 0;
	    /* remember that cnt can be negative */
	    SvGROW(sv, append + (cnt <= 0 ? 2 : (cnt + 1)));
	}
    }
    else
	shortbuffered = 0;
    bp = (STDCHAR*)SvPVX(sv) + append;  /* move these two too to registers */
    ptr = (STDCHAR*)PerlIO_get_ptr(fp);
    DEBUG_P(PerlIO_printf(Perl_debug_log,
	"Screamer: entering, ptr=%ld, cnt=%ld\n",(long)ptr,(long)cnt));
    DEBUG_P(PerlIO_printf(Perl_debug_log,
	"Screamer: entering: FILE * thinks ptr=%ld, cnt=%ld, base=%ld\n",
	       (long)PerlIO_get_ptr(fp), (long)PerlIO_get_cnt(fp), 
	       (long)(PerlIO_has_base(fp) ? PerlIO_get_base(fp) : 0)));
    for (;;) {
      screamer:
	if (cnt > 0) {
	    if (rslen) {
		while (cnt > 0) {		     /* this     |  eat */
		    cnt--;
		    if ((*bp++ = *ptr++) == rslast)  /* really   |  dust */
			goto thats_all_folks;	     /* screams  |  sed :-) */
		}
	    }
	    else {
	        Copy(ptr, bp, cnt, char);	     /* this     |  eat */    
		bp += cnt;			     /* screams  |  dust */   
		ptr += cnt;			     /* louder   |  sed :-) */
		cnt = 0;
	    }
	}
	
	if (shortbuffered) {		/* oh well, must extend */
	    cnt = shortbuffered;
	    shortbuffered = 0;
	    bpx = bp - (STDCHAR*)SvPVX(sv); /* box up before relocation */
	    SvCUR_set(sv, bpx);
	    SvGROW(sv, SvLEN(sv) + append + cnt + 2);
	    bp = (STDCHAR*)SvPVX(sv) + bpx; /* unbox after relocation */
	    continue;
	}

	DEBUG_P(PerlIO_printf(Perl_debug_log,
	    "Screamer: going to getc, ptr=%ld, cnt=%ld\n",(long)ptr,(long)cnt));
	PerlIO_set_ptrcnt(fp, ptr, cnt); /* deregisterize cnt and ptr */
	DEBUG_P(PerlIO_printf(Perl_debug_log,
	    "Screamer: pre: FILE * thinks ptr=%ld, cnt=%ld, base=%ld\n",
	    (long)PerlIO_get_ptr(fp), (long)PerlIO_get_cnt(fp), 
	    (long)(PerlIO_has_base (fp) ? PerlIO_get_base(fp) : 0)));
	/* This used to call 'filbuf' in stdio form, but as that behaves like 
	   getc when cnt <= 0 we use PerlIO_getc here to avoid introducing
	   another abstraction.  */
	i   = PerlIO_getc(fp);		/* get more characters */
	DEBUG_P(PerlIO_printf(Perl_debug_log,
	    "Screamer: post: FILE * thinks ptr=%ld, cnt=%ld, base=%ld\n",
	    (long)PerlIO_get_ptr(fp), (long)PerlIO_get_cnt(fp), 
	    (long)(PerlIO_has_base (fp) ? PerlIO_get_base(fp) : 0)));
	cnt = PerlIO_get_cnt(fp);
	ptr = (STDCHAR*)PerlIO_get_ptr(fp);	/* reregisterize cnt and ptr */
	DEBUG_P(PerlIO_printf(Perl_debug_log,
	    "Screamer: after getc, ptr=%ld, cnt=%ld\n",(long)ptr,(long)cnt));

	if (i == EOF)			/* all done for ever? */
	    goto thats_really_all_folks;

	bpx = bp - (STDCHAR*)SvPVX(sv);	/* box up before relocation */
	SvCUR_set(sv, bpx);
	SvGROW(sv, bpx + cnt + 2);
	bp = (STDCHAR*)SvPVX(sv) + bpx;	/* unbox after relocation */

	*bp++ = i;			/* store character from PerlIO_getc */

	if (rslen && (STDCHAR)i == rslast)  /* all done for now? */
	    goto thats_all_folks;
    }

thats_all_folks:
    if ((rslen > 1 && (bp - (STDCHAR*)SvPVX(sv) < rslen)) ||
	  memNE((char*)bp - rslen, rsptr, rslen))
	goto screamer;				/* go back to the fray */
thats_really_all_folks:
    if (shortbuffered)
	cnt += shortbuffered;
	DEBUG_P(PerlIO_printf(Perl_debug_log,
	    "Screamer: quitting, ptr=%ld, cnt=%ld\n",(long)ptr,(long)cnt));
    PerlIO_set_ptrcnt(fp, ptr, cnt);	/* put these back or we're in trouble */
    DEBUG_P(PerlIO_printf(Perl_debug_log,
	"Screamer: end: FILE * thinks ptr=%ld, cnt=%ld, base=%ld\n",
	(long)PerlIO_get_ptr(fp), (long)PerlIO_get_cnt(fp), 
	(long)(PerlIO_has_base (fp) ? PerlIO_get_base(fp) : 0)));
    *bp = '\0';
    SvCUR_set(sv, bp - (STDCHAR*)SvPVX(sv));	/* set length */
    DEBUG_P(PerlIO_printf(Perl_debug_log,
	"Screamer: done, len=%ld, string=|%.*s|\n",
	(long)SvCUR(sv),(int)SvCUR(sv),SvPVX(sv)));
    }
   else
    {
       /*The big, slow, and stupid way */
	STDCHAR buf[8192];

screamer2:
	if (rslen) {
	    register STDCHAR *bpe = buf + sizeof(buf);
	    bp = buf;
	    while ((i = PerlIO_getc(fp)) != EOF && (*bp++ = i) != rslast && bp < bpe)
		; /* keep reading */
	    cnt = bp - buf;
	}
	else {
	    cnt = PerlIO_read(fp,(char*)buf, sizeof(buf));
	    /* Accomodate broken VAXC compiler, which applies U8 cast to
	     * both args of ?: operator, causing EOF to change into 255
	     */
	    if (cnt) { i = (U8)buf[cnt - 1]; } else { i = EOF; }
	}

	if (append)
	    sv_catpvn(sv, (char *) buf, cnt);
	else
	    sv_setpvn(sv, (char *) buf, cnt);

	if (i != EOF &&			/* joy */
	    (!rslen ||
	     SvCUR(sv) < rslen ||
	     memNE(SvPVX(sv) + SvCUR(sv) - rslen, rsptr, rslen)))
	{
	    append = -1;
	    /*
	     * If we're reading from a TTY and we get a short read,
	     * indicating that the user hit his EOF character, we need
	     * to notice it now, because if we try to read from the TTY
	     * again, the EOF condition will disappear.
	     *
	     * The comparison of cnt to sizeof(buf) is an optimization
	     * that prevents unnecessary calls to feof().
	     *
	     * - jik 9/25/96
	     */
	    if (!(cnt < sizeof(buf) && PerlIO_eof(fp)))
		goto screamer2;
	}
    }

    if (RsPARA(rs)) {		/* have to do this both before and after */  
        while (i != EOF) {	/* to make sure file boundaries work right */
	    i = PerlIO_getc(fp);
	    if (i != '\n') {
		PerlIO_ungetc(fp,i);
		break;
	    }
	}
    }

#ifdef WIN32
    win32_strip_return(sv);
#endif

    return (SvCUR(sv) - append) ? SvPVX(sv) : Nullch;
}


void
sv_inc(register SV *sv)
{
    register char *d;
    int flags;

    if (!sv)
	return;
    if (SvTHINKFIRST(sv)) {
	if (SvREADONLY(sv)) {
	    dTHR;
	    if (curcop != &compiling)
		croak(no_modify);
	}
	if (SvROK(sv)) {
#ifdef OVERLOAD
	  if (SvAMAGIC(sv) && AMG_CALLun(sv,inc)) return;
#endif /* OVERLOAD */
	  sv_unref(sv);
	}
    }
    if (SvGMAGICAL(sv))
	mg_get(sv);
    flags = SvFLAGS(sv);
    if (flags & SVp_NOK) {
	(void)SvNOK_only(sv);
	SvNVX(sv) += 1.0;
	return;
    }
    if (flags & SVp_IOK) {
	if (SvIVX(sv) == IV_MAX)
	    sv_setnv(sv, (double)IV_MAX + 1.0);
	else {
	    (void)SvIOK_only(sv);
	    ++SvIVX(sv);
	}
	return;
    }
    if (!(flags & SVp_POK) || !*SvPVX(sv)) {
	if ((flags & SVTYPEMASK) < SVt_PVNV)
	    sv_upgrade(sv, SVt_NV);
	SvNVX(sv) = 1.0;
	(void)SvNOK_only(sv);
	return;
    }
    d = SvPVX(sv);
    while (isALPHA(*d)) d++;
    while (isDIGIT(*d)) d++;
    if (*d) {
	SET_NUMERIC_STANDARD();
	sv_setnv(sv,atof(SvPVX(sv)) + 1.0);  /* punt */
	return;
    }
    d--;
    while (d >= SvPVX(sv)) {
	if (isDIGIT(*d)) {
	    if (++*d <= '9')
		return;
	    *(d--) = '0';
	}
	else {
	    ++*d;
	    if (isALPHA(*d))
		return;
	    *(d--) -= 'z' - 'a' + 1;
	}
    }
    /* oh,oh, the number grew */
    SvGROW(sv, SvCUR(sv) + 2);
    SvCUR(sv)++;
    for (d = SvPVX(sv) + SvCUR(sv); d > SvPVX(sv); d--)
	*d = d[-1];
    if (isDIGIT(d[1]))
	*d = '1';
    else
	*d = d[1];
}

void
sv_dec(register SV *sv)
{
    int flags;

    if (!sv)
	return;
    if (SvTHINKFIRST(sv)) {
	if (SvREADONLY(sv)) {
	    dTHR;
	    if (curcop != &compiling)
		croak(no_modify);
	}
	if (SvROK(sv)) {
#ifdef OVERLOAD
	  if (SvAMAGIC(sv) && AMG_CALLun(sv,dec)) return;
#endif /* OVERLOAD */
	  sv_unref(sv);
	}
    }
    if (SvGMAGICAL(sv))
	mg_get(sv);
    flags = SvFLAGS(sv);
    if (flags & SVp_NOK) {
	SvNVX(sv) -= 1.0;
	(void)SvNOK_only(sv);
	return;
    }
    if (flags & SVp_IOK) {
	if (SvIVX(sv) == IV_MIN)
	    sv_setnv(sv, (double)IV_MIN - 1.0);
	else {
	    (void)SvIOK_only(sv);
	    --SvIVX(sv);
	}
	return;
    }
    if (!(flags & SVp_POK)) {
	if ((flags & SVTYPEMASK) < SVt_PVNV)
	    sv_upgrade(sv, SVt_NV);
	SvNVX(sv) = -1.0;
	(void)SvNOK_only(sv);
	return;
    }
    SET_NUMERIC_STANDARD();
    sv_setnv(sv,atof(SvPVX(sv)) - 1.0);	/* punt */
}

/* Make a string that will exist for the duration of the expression
 * evaluation.  Actually, it may have to last longer than that, but
 * hopefully we won't free it until it has been assigned to a
 * permanent location. */

static void
sv_mortalgrow(void)
{
    dTHR;
    tmps_max += (tmps_max < 512) ? 128 : 512;
    Renew(tmps_stack, tmps_max, SV*);
}

SV *
sv_mortalcopy(SV *oldstr)
{
    dTHR;
    register SV *sv;

    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
    sv_setsv(sv,oldstr);
    if (++tmps_ix >= tmps_max)
	sv_mortalgrow();
    tmps_stack[tmps_ix] = sv;
    SvTEMP_on(sv);
    return sv;
}

SV *
sv_newmortal(void)
{
    dTHR;
    register SV *sv;

    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = SVs_TEMP;
    if (++tmps_ix >= tmps_max)
	sv_mortalgrow();
    tmps_stack[tmps_ix] = sv;
    return sv;
}

/* same thing without the copying */

SV *
sv_2mortal(register SV *sv)
{
    dTHR;
    if (!sv)
	return sv;
    if (SvREADONLY(sv) && curcop != &compiling)
	croak(no_modify);
    if (++tmps_ix >= tmps_max)
	sv_mortalgrow();
    tmps_stack[tmps_ix] = sv;
    SvTEMP_on(sv);
    return sv;
}

SV *
newSVpv(char *s, STRLEN len)
{
    register SV *sv;

    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
    if (!len)
	len = strlen(s);
    sv_setpvn(sv,s,len);
    return sv;
}

#ifdef I_STDARG
SV *
newSVpvf(const char* pat, ...)
#else
/*VARARGS0*/
SV *
newSVpvf(pat, va_alist)
const char *pat;
va_dcl
#endif
{
    register SV *sv;
    va_list args;

    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
#ifdef I_STDARG
    va_start(args, pat);
#else
    va_start(args);
#endif
    sv_vsetpvfn(sv, pat, strlen(pat), &args, Null(SV**), 0, Null(bool*));
    va_end(args);
    return sv;
}


SV *
newSVnv(double n)
{
    register SV *sv;

    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
    sv_setnv(sv,n);
    return sv;
}

SV *
newSViv(IV i)
{
    register SV *sv;

    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
    sv_setiv(sv,i);
    return sv;
}

SV *
newRV(SV *ref)
{
    dTHR;
    register SV *sv;

    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
    sv_upgrade(sv, SVt_RV);
    SvTEMP_off(ref);
    SvRV(sv) = SvREFCNT_inc(ref);
    SvROK_on(sv);
    return sv;
}



SV *
Perl_newRV_noinc(SV *ref)
{
    register SV *sv;

    sv = newRV(ref);
    SvREFCNT_dec(ref);
    return sv;
}

/* make an exact duplicate of old */

SV *
newSVsv(register SV *old)
{
    register SV *sv;

    if (!old)
	return Nullsv;
    if (SvTYPE(old) == SVTYPEMASK) {
	warn("semi-panic: attempt to dup freed string");
	return Nullsv;
    }
    new_SV(sv);
    SvANY(sv) = 0;
    SvREFCNT(sv) = 1;
    SvFLAGS(sv) = 0;
    if (SvTEMP(old)) {
	SvTEMP_off(old);
	sv_setsv(sv,old);
	SvTEMP_on(old);
    }
    else
	sv_setsv(sv,old);
    return sv;
}

void
sv_reset(register char *s, HV *stash)
{
    register HE *entry;
    register GV *gv;
    register SV *sv;
    register I32 i;
    register PMOP *pm;
    register I32 max;
    char todo[256];

    if (!*s) {		/* reset ?? searches */
	for (pm = HvPMROOT(stash); pm; pm = pm->op_pmnext) {
	    pm->op_pmflags &= ~PMf_USED;
	}
	return;
    }

    /* reset variables */

    if (!HvARRAY(stash))
	return;

    Zero(todo, 256, char);
    while (*s) {
	i = *s;
	if (s[1] == '-') {
	    s += 2;
	}
	max = *s++;
	for ( ; i <= max; i++) {
	    todo[i] = 1;
	}
	for (i = 0; i <= (I32) HvMAX(stash); i++) {
	    for (entry = HvARRAY(stash)[i];
	      entry;
	      entry = HeNEXT(entry)) {
		if (!todo[(U8)*HeKEY(entry)])
		    continue;
		gv = (GV*)HeVAL(entry);
		sv = GvSV(gv);
		(void)SvOK_off(sv);
		if (SvTYPE(sv) >= SVt_PV) {
		    SvCUR_set(sv, 0);
		    if (SvPVX(sv) != Nullch)
			*SvPVX(sv) = '\0';
		    SvTAINT(sv);
		}
		if (GvAV(gv)) {
		    av_clear(GvAV(gv));
		}
		if (GvHV(gv) && !HvNAME(GvHV(gv))) {
		    hv_clear(GvHV(gv));
#ifndef VMS  /* VMS has no environ array */
		    if (gv == envgv)
			environ[0] = Nullch;
#endif
		}
	    }
	}
    }
}

IO*
sv_2io(SV *sv)
{
    IO* io;
    GV* gv;

    switch (SvTYPE(sv)) {
    case SVt_PVIO:
	io = (IO*)sv;
	break;
    case SVt_PVGV:
	gv = (GV*)sv;
	io = GvIO(gv);
	if (!io)
	    croak("Bad filehandle: %s", GvNAME(gv));
	break;
    default:
	if (!SvOK(sv))
	    croak(no_usym, "filehandle");
	if (SvROK(sv))
	    return sv_2io(SvRV(sv));
	gv = gv_fetchpv(SvPV(sv,na), FALSE, SVt_PVIO);
	if (gv)
	    io = GvIO(gv);
	else
	    io = 0;
	if (!io)
	    croak("Bad filehandle: %s", SvPV(sv,na));
	break;
    }
    return io;
}

CV *
sv_2cv(SV *sv, HV **st, GV **gvp, I32 lref)
{
    GV *gv;
    CV *cv;

    if (!sv)
	return *gvp = Nullgv, Nullcv;
    switch (SvTYPE(sv)) {
    case SVt_PVCV:
	*st = CvSTASH(sv);
	*gvp = Nullgv;
	return (CV*)sv;
    case SVt_PVHV:
    case SVt_PVAV:
	*gvp = Nullgv;
	return Nullcv;
    case SVt_PVGV:
	gv = (GV*)sv;
	*gvp = gv;
	*st = GvESTASH(gv);
	goto fix_gv;

    default:
	if (SvGMAGICAL(sv))
	    mg_get(sv);
	if (SvROK(sv)) {
	    cv = (CV*)SvRV(sv);
	    if (SvTYPE(cv) != SVt_PVCV)
		croak("Not a subroutine reference");
	    *gvp = Nullgv;
	    *st = CvSTASH(cv);
	    return cv;
	}
	if (isGV(sv))
	    gv = (GV*)sv;
	else
	    gv = gv_fetchpv(SvPV(sv, na), lref, SVt_PVCV);
	*gvp = gv;
	if (!gv)
	    return Nullcv;
	*st = GvESTASH(gv);
    fix_gv:
	if (lref && !GvCVu(gv)) {
	    SV *tmpsv;
	    ENTER;
	    tmpsv = NEWSV(704,0);
	    gv_efullname3(tmpsv, gv, Nullch);
	    newSUB(start_subparse(FALSE, 0),
		   newSVOP(OP_CONST, 0, tmpsv),
		   Nullop,
		   Nullop);
	    LEAVE;
	    if (!GvCVu(gv))
		croak("Unable to create sub named \"%s\"", SvPV(sv,na));
	}
	return GvCVu(gv);
    }
}

I32
sv_true(register SV *sv)
{
    dTHR;
    if (!sv)
	return 0;
    if (SvGMAGICAL(sv))
	mg_get(sv);
    if (SvPOK(sv)) {
	register XPV* tXpv;
	if ((tXpv = (XPV*)SvANY(sv)) &&
		(*tXpv->xpv_pv > '0' ||
		tXpv->xpv_cur > 1 ||
		(tXpv->xpv_cur && *tXpv->xpv_pv != '0')))
	    return 1;
	else
	    return 0;
    }
    else {
	if (SvIOK(sv))
	    return SvIVX(sv) != 0;
	else {
	    if (SvNOK(sv))