sv.h

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/*    sv.h
 *
 *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
 *    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, by Larry Wall and others
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 */

#ifdef sv_flags
#undef sv_flags		/* Convex has this in <signal.h> for sigvec() */
#endif

/*
=head1 SV Flags

=for apidoc AmU||svtype
An enum of flags for Perl types.  These are found in the file B<sv.h>
in the C<svtype> enum.  Test these flags with the C<SvTYPE> macro.

=for apidoc AmU||SVt_PV
Pointer type flag for scalars.  See C<svtype>.

=for apidoc AmU||SVt_IV
Integer type flag for scalars.  See C<svtype>.

=for apidoc AmU||SVt_NV
Double type flag for scalars.  See C<svtype>.

=for apidoc AmU||SVt_PVMG
Type flag for blessed scalars.  See C<svtype>.

=for apidoc AmU||SVt_PVAV
Type flag for arrays.  See C<svtype>.

=for apidoc AmU||SVt_PVHV
Type flag for hashes.  See C<svtype>.

=for apidoc AmU||SVt_PVCV
Type flag for code refs.  See C<svtype>.

=cut
*/

typedef enum {
	SVt_NULL,	/* 0 */
	SVt_BIND,	/* 1 */
	SVt_IV,		/* 2 */
	SVt_NV,		/* 3 */
	SVt_RV,		/* 4 */
	SVt_PV,		/* 5 */
	SVt_PVIV,	/* 6 */
	SVt_PVNV,	/* 7 */
	SVt_PVMG,	/* 8 */
	/* PVBM was here, before BIND replaced it.  */
	SVt_PVGV,	/* 9 */
	SVt_PVLV,	/* 10 */
	SVt_PVAV,	/* 11 */
	SVt_PVHV,	/* 12 */
	SVt_PVCV,	/* 13 */
	SVt_PVFM,	/* 14 */
	SVt_PVIO,	/* 15 */
	SVt_LAST	/* keep last in enum. used to size arrays */
} svtype;

#ifndef PERL_CORE
/* Although Fast Boyer Moore tables are now being stored in PVGVs, for most
   purposes eternal code wanting to consider PVBM probably needs to think of
   PVMG instead.  */
#  define SVt_PVBM	SVt_PVMG
#endif

/* There is collusion here with sv_clear - sv_clear exits early for SVt_NULL
   and SVt_IV, so never reaches the clause at the end that uses
   sv_type_details->body_size to determine whether to call safefree(). Hence
   body_size can be set no-zero to record the size of PTEs and HEs, without
   fear of bogus frees.  */
#ifdef PERL_IN_SV_C
#define PTE_SVSLOT	SVt_IV
#endif
#if defined(PERL_IN_HV_C) || defined(PERL_IN_XS_APITEST)
#define HE_SVSLOT	SVt_NULL
#endif

#define PERL_ARENA_ROOTS_SIZE	(SVt_LAST)

/* typedefs to eliminate some typing */
typedef struct he HE;
typedef struct hek HEK;

/* Using C's structural equivalence to help emulate C++ inheritance here... */

/* start with 2 sv-head building blocks */
#define _SV_HEAD(ptrtype) \
    ptrtype	sv_any;		/* pointer to body */	\
    U32		sv_refcnt;	/* how many references to us */	\
    U32		sv_flags	/* what we are */

#define _SV_HEAD_UNION \
    union {				\
	IV      svu_iv;			\
	UV      svu_uv;			\
	SV*     svu_rv;		/* pointer to another SV */		\
	char*   svu_pv;		/* pointer to malloced string */	\
	SV**    svu_array;		\
	HE**	svu_hash;		\
	GP*	svu_gp;			\
    }	sv_u


struct STRUCT_SV {		/* struct sv { */
    _SV_HEAD(void*);
    _SV_HEAD_UNION;
#ifdef DEBUG_LEAKING_SCALARS
    unsigned	sv_debug_optype:9;	/* the type of OP that allocated us */
    unsigned	sv_debug_inpad:1;	/* was allocated in a pad for an OP */
    unsigned	sv_debug_cloned:1;	/* was cloned for an ithread */
    unsigned	sv_debug_line:16;	/* the line where we were allocated */
    char *	sv_debug_file;		/* the file where we were allocated */
#endif
};

struct gv {
    _SV_HEAD(XPVGV*);		/* pointer to xpvgv body */
    _SV_HEAD_UNION;
};

struct cv {
    _SV_HEAD(XPVCV*);		/* pointer to xpvcv body */
    _SV_HEAD_UNION;
};

struct av {
    _SV_HEAD(XPVAV*);		/* pointer to xpvav body */
    _SV_HEAD_UNION;
};

struct hv {
    _SV_HEAD(XPVHV*);		/* pointer to xpvhv body */
    _SV_HEAD_UNION;
};

struct io {
    _SV_HEAD(XPVIO*);		/* pointer to xpvio body */
    _SV_HEAD_UNION;
};

#undef _SV_HEAD
#undef _SV_HEAD_UNION		/* ensure no pollution */

/*
=head1 SV Manipulation Functions

=for apidoc Am|U32|SvREFCNT|SV* sv
Returns the value of the object's reference count.

=for apidoc Am|SV*|SvREFCNT_inc|SV* sv
Increments the reference count of the given SV.

All of the following SvREFCNT_inc* macros are optimized versions of
SvREFCNT_inc, and can be replaced with SvREFCNT_inc.

=for apidoc Am|SV*|SvREFCNT_inc_NN|SV* sv
Same as SvREFCNT_inc, but can only be used if you know I<sv>
is not NULL.  Since we don't have to check the NULLness, it's faster
and smaller.

=for apidoc Am|void|SvREFCNT_inc_void|SV* sv
Same as SvREFCNT_inc, but can only be used if you don't need the
return value.  The macro doesn't need to return a meaningful value.

=for apidoc Am|void|SvREFCNT_inc_void_NN|SV* sv
Same as SvREFCNT_inc, but can only be used if you don't need the return
value, and you know that I<sv> is not NULL.  The macro doesn't need
to return a meaningful value, or check for NULLness, so it's smaller
and faster.

=for apidoc Am|SV*|SvREFCNT_inc_simple|SV* sv
Same as SvREFCNT_inc, but can only be used with expressions without side
effects.  Since we don't have to store a temporary value, it's faster.

=for apidoc Am|SV*|SvREFCNT_inc_simple_NN|SV* sv
Same as SvREFCNT_inc_simple, but can only be used if you know I<sv>
is not NULL.  Since we don't have to check the NULLness, it's faster
and smaller.

=for apidoc Am|void|SvREFCNT_inc_simple_void|SV* sv
Same as SvREFCNT_inc_simple, but can only be used if you don't need the
return value.  The macro doesn't need to return a meaningful value.

=for apidoc Am|void|SvREFCNT_inc_simple_void_NN|SV* sv
Same as SvREFCNT_inc, but can only be used if you don't need the return
value, and you know that I<sv> is not NULL.  The macro doesn't need
to return a meaningful value, or check for NULLness, so it's smaller
and faster.

=for apidoc Am|void|SvREFCNT_dec|SV* sv
Decrements the reference count of the given SV.

=for apidoc Am|svtype|SvTYPE|SV* sv
Returns the type of the SV.  See C<svtype>.

=for apidoc Am|void|SvUPGRADE|SV* sv|svtype type
Used to upgrade an SV to a more complex form.  Uses C<sv_upgrade> to
perform the upgrade if necessary.  See C<svtype>.

=cut
*/

#define SvANY(sv)	(sv)->sv_any
#define SvFLAGS(sv)	(sv)->sv_flags
#define SvREFCNT(sv)	(sv)->sv_refcnt

#if defined(__GNUC__) && !defined(__STRICT_ANSI__) && !defined(PERL_GCC_PEDANTIC)
#  define SvREFCNT_inc(sv)		\
    ({					\
	SV * const _sv = (SV*)(sv);	\
	if (_sv)			\
	     (SvREFCNT(_sv))++;		\
	_sv;				\
    })
#  define SvREFCNT_inc_simple(sv)	\
    ({					\
	if (sv)				\
	     (SvREFCNT(sv))++;		\
	(SV *)(sv);				\
    })
#  define SvREFCNT_inc_NN(sv)		\
    ({					\
	SV * const _sv = (SV*)(sv);	\
	SvREFCNT(_sv)++;		\
	_sv;				\
    })
#  define SvREFCNT_inc_void(sv)		\
    ({					\
	SV * const _sv = (SV*)(sv);	\
	if (_sv)			\
	    (void)(SvREFCNT(_sv)++);	\
    })
#else
#  define SvREFCNT_inc(sv)	\
	((PL_Sv=(SV*)(sv)) ? (++(SvREFCNT(PL_Sv)),PL_Sv) : NULL)
#  define SvREFCNT_inc_simple(sv) \
	((sv) ? (SvREFCNT(sv)++,(SV*)(sv)) : NULL)
#  define SvREFCNT_inc_NN(sv) \
	(PL_Sv=(SV*)(sv),++(SvREFCNT(PL_Sv)),PL_Sv)
#  define SvREFCNT_inc_void(sv) \
	(void)((PL_Sv=(SV*)(sv)) ? ++(SvREFCNT(PL_Sv)) : 0)
#endif

/* These guys don't need the curly blocks */
#define SvREFCNT_inc_simple_void(sv)	STMT_START { if (sv) SvREFCNT(sv)++; } STMT_END
#define SvREFCNT_inc_simple_NN(sv)	(++(SvREFCNT(sv)),(SV*)(sv))
#define SvREFCNT_inc_void_NN(sv)	(void)(++SvREFCNT((SV*)(sv)))
#define SvREFCNT_inc_simple_void_NN(sv)	(void)(++SvREFCNT((SV*)(sv)))

#if defined(__GNUC__) && !defined(__STRICT_ANSI__) && !defined(PERL_GCC_PEDANTIC)
#  define SvREFCNT_dec(sv)		\
    ({					\
	SV * const _sv = (SV*)(sv);	\
	if (_sv) {			\
	    if (SvREFCNT(_sv)) {	\
		if (--(SvREFCNT(_sv)) == 0) \
		    Perl_sv_free2(aTHX_ _sv);	\
	    } else {			\
		sv_free(_sv);		\
	    }				\
	}				\
    })
#else
#define SvREFCNT_dec(sv)	sv_free((SV*)(sv))
#endif

#define SVTYPEMASK	0xff
#define SvTYPE(sv)	((svtype)((sv)->sv_flags & SVTYPEMASK))

/* Sadly there are some parts of the core that have pointers to already-freed
   SV heads, and rely on being able to tell that they are now free. So mark
   them all by using a consistent macro.  */
#define SvIS_FREED(sv)	((sv)->sv_flags == SVTYPEMASK)

#define SvUPGRADE(sv, mt) (SvTYPE(sv) >= (mt) || (sv_upgrade(sv, mt), 1))

#define SVf_IOK		0x00000100  /* has valid public integer value */
#define SVf_NOK		0x00000200  /* has valid public numeric value */
#define SVf_POK		0x00000400  /* has valid public pointer value */
#define SVf_ROK		0x00000800  /* has a valid reference pointer */

#define SVp_IOK		0x00001000  /* has valid non-public integer value */
#define SVp_NOK		0x00002000  /* has valid non-public numeric value */
#define SVp_POK		0x00004000  /* has valid non-public pointer value */
#define SVp_SCREAM	0x00008000  /* has been studied? */
#define SVphv_CLONEABLE	SVp_SCREAM  /* PVHV (stashes) clone its objects */
#define SVpgv_GP	SVp_SCREAM  /* GV has a valid GP */
#define SVprv_PCS_IMPORTED  SVp_SCREAM  /* RV is a proxy for a constant
				       subroutine in another package. Set the
				       CvIMPORTED_CV_ON() if it needs to be
				       expanded to a real GV */

#define SVs_PADSTALE	0x00010000  /* lexical has gone out of scope */
#define SVpad_STATE	0x00010000  /* pad name is a "state" var */
#define SVs_PADTMP	0x00020000  /* in use as tmp */
#define SVpad_TYPED	0x00020000  /* pad name is a Typed Lexical */
#define SVs_PADMY	0x00040000  /* in use a "my" variable */
#define SVpad_OUR	0x00040000  /* pad name is "our" instead of "my" */
#define SVs_TEMP	0x00080000  /* string is stealable? */
#define SVs_OBJECT	0x00100000  /* is "blessed" */
#define SVs_GMG		0x00200000  /* has magical get method */
#define SVs_SMG		0x00400000  /* has magical set method */
#define SVs_RMG		0x00800000  /* has random magical methods */

#define SVf_FAKE	0x01000000  /* 0: glob or lexical is just a copy
				       1: SV head arena wasn't malloc()ed
				       2: in conjunction with SVf_READONLY
					  marks a shared hash key scalar
					  (SvLEN == 0) or a copy on write
					  string (SvLEN != 0) [SvIsCOW(sv)]
				       3: For PVCV, whether CvUNIQUE(cv)
					  refers to an eval or once only
					  [CvEVAL(cv), CvSPECIAL(cv)]
				       4: Whether the regexp pointer is in
					  fact an offset [SvREPADTMP(sv)]
				       5: On a pad name SV, that slot in the
					  frame AV is a REFCNT'ed reference
					  to a lexical from "outside". */
#define SVphv_REHASH	SVf_FAKE    /* 6: On a PVHV, hash values are being
					  recalculated */
#define SVf_OOK		0x02000000  /* has valid offset value. For a PVHV this
				       means that a hv_aux struct is present
				       after the main array */
#define SVf_BREAK	0x04000000  /* refcnt is artificially low - used by
				       SV's in final arena cleanup */
#define SVf_READONLY	0x08000000  /* may not be modified */




#define SVf_THINKFIRST	(SVf_READONLY|SVf_ROK|SVf_FAKE)

#define SVf_OK		(SVf_IOK|SVf_NOK|SVf_POK|SVf_ROK| \
			 SVp_IOK|SVp_NOK|SVp_POK|SVpgv_GP)

#define PRIVSHIFT 4	/* (SVp_?OK >> PRIVSHIFT) == SVf_?OK */

#define SVf_AMAGIC	0x10000000  /* has magical overloaded methods */

/* Ensure this value does not clash with the GV_ADD* flags in gv.h: */
#define SVf_UTF8        0x20000000  /* SvPV is UTF-8 encoded
				       This is also set on RVs whose overloaded
				       stringification is UTF-8. This might
				       only happen as a side effect of SvPV() */
					   

/* Some private flags. */

/* PVAV could probably use 0x2000000 without conflict. I assume that PVFM can
   be UTF-8 encoded, and PVCVs could well have UTF-8 prototypes. PVIOs haven't
   been restructured, so sometimes get used as string buffers.  */

/* PVHV */
#define SVphv_SHAREKEYS 0x20000000  /* PVHV keys live on shared string table */
/* PVNV, PVMG, presumably only inside pads */
#define SVpad_NAME	0x40000000  /* This SV is a name in the PAD, so
				       SVpad_TYPED, SVpad_OUR and SVpad_STATE
				       apply */
/* PVAV */
#define SVpav_REAL	0x40000000  /* free old entries */
/* PVHV */
#define SVphv_LAZYDEL	0x40000000  /* entry in xhv_eiter must be deleted */
/* This is only set true on a PVGV when it's playing "PVBM", but is tested for
   on any regular scalar (anything <= PVLV) */
#define SVpbm_VALID	0x40000000
/* ??? */
#define SVrepl_EVAL	0x40000000  /* Replacement part of s///e */

/* IV, PVIV, PVNV, PVMG, PVGV and (I assume) PVLV  */
/* Presumably IVs aren't stored in pads */
#define SVf_IVisUV	0x80000000  /* use XPVUV instead of XPVIV */
/* PVAV */
#define SVpav_REIFY 	0x80000000  /* can become real */