[perl5.git] / hv.h

/*    hv.h
 *
 *    Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
 *    2000, 2001, 2002, 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.
 *
 */

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

/* entry in hash value chain */
struct he {
    HE		*hent_next;	/* next entry in chain */
    HEK		*hent_hek;	/* hash key */
    SV		*hent_val;	/* scalar value that was hashed */
};

/* hash key -- defined separately for use as shared pointer */
struct hek {
    U32		hek_hash;	/* hash of key */
    I32		hek_len;	/* length of hash key */
    char	hek_key[1];	/* variable-length hash key */
    /* the hash-key is \0-terminated */
    /* after the \0 there is a byte for flags, such as whether the key
       is UTF-8 */
};

/* hash structure: */
/* This structure must match the beginning of struct xpvmg in sv.h. */
struct xpvhv {
    char *	xhv_array;	/* pointer to malloced string */
    STRLEN	xhv_fill;	/* how full xhv_array currently is */
    STRLEN	xhv_max;	/* subscript of last element of xhv_array */
    IV		xhv_keys;	/* how many elements in the array */
    NV		xnv_nv;		/* numeric value, if any */
#define xhv_placeholders xnv_nv
    MAGIC*	xmg_magic;	/* magic for scalar array */
    HV*		xmg_stash;	/* class package */

    I32		xhv_riter;	/* current root of iterator */
    HE		*xhv_eiter;	/* current entry of iterator */
    PMOP	*xhv_pmroot;	/* list of pm's for this package */
    char	*xhv_name;	/* name, if a symbol table */
};

/* hash a key */
/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins
 * from requirements by Colin Plumb.
 * (http://burtleburtle.net/bob/hash/doobs.html) */
/* The use of a temporary pointer and the casting games
 * is needed to serve the dual purposes of
 * (a) the hashed data being interpreted as "unsigned char" (new since 5.8,
 *     a "char" can be either signed or signed, depending on the compiler)
 * (b) catering for old code that uses a "char"
 *
 * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
 * to avoid "algorithmic complexity attacks".
 *
 * If USE_HASH_SEED is defined, hash randomisation is done by default
 * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done
 * only if the environment variable PERL_HASH_SEED is set.
 * For maximal control, one can define PERL_HASH_SEED.
 * (see also erl.c:perl_parse()).
 */
#ifndef PERL_HASH_SEED
#   if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
#       define PERL_HASH_SEED	PL_hash_seed
#   else
#       define PERL_HASH_SEED	0
#   endif
#endif
#define PERL_HASH(hash,str,len) \
     STMT_START	{ \
	register const char *s_PeRlHaSh_tmp = str; \
	register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
	register I32 i_PeRlHaSh = len; \
	register U32 hash_PeRlHaSh = PERL_HASH_SEED; \
	while (i_PeRlHaSh--) { \
	    hash_PeRlHaSh += *s_PeRlHaSh++; \
	    hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
	    hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
	} \
	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
    } STMT_END

#ifdef PERL_IN_HV_C
#define PERL_HASH_INTERNAL(hash,str,len) \
     STMT_START	{ \
	register const char *s_PeRlHaSh_tmp = str; \
	register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
	register I32 i_PeRlHaSh = len; \
	register U32 hash_PeRlHaSh = PL_new_hash_seed; \
	while (i_PeRlHaSh--) { \
	    hash_PeRlHaSh += *s_PeRlHaSh++; \
	    hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
	    hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
	} \
	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
    } STMT_END
#endif

/*
=head1 Hash Manipulation Functions

=for apidoc AmU||HEf_SVKEY
This flag, used in the length slot of hash entries and magic structures,
specifies the structure contains an C<SV*> pointer where a C<char*> pointer
is to be expected. (For information only--not to be used).

=head1 Handy Values

=for apidoc AmU||Nullhv
Null HV pointer.

=head1 Hash Manipulation Functions

=for apidoc Am|char*|HvNAME|HV* stash
Returns the package name of a stash.  See C<SvSTASH>, C<CvSTASH>.

=for apidoc Am|void*|HeKEY|HE* he
Returns the actual pointer stored in the key slot of the hash entry. The
pointer may be either C<char*> or C<SV*>, depending on the value of
C<HeKLEN()>.  Can be assigned to.  The C<HePV()> or C<HeSVKEY()> macros are
usually preferable for finding the value of a key.

=for apidoc Am|STRLEN|HeKLEN|HE* he
If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
holds an C<SV*> key.  Otherwise, holds the actual length of the key.  Can
be assigned to. The C<HePV()> macro is usually preferable for finding key
lengths.

=for apidoc Am|SV*|HeVAL|HE* he
Returns the value slot (type C<SV*>) stored in the hash entry.

=for apidoc Am|U32|HeHASH|HE* he
Returns the computed hash stored in the hash entry.

=for apidoc Am|char*|HePV|HE* he|STRLEN len
Returns the key slot of the hash entry as a C<char*> value, doing any
necessary dereferencing of possibly C<SV*> keys.  The length of the string
is placed in C<len> (this is a macro, so do I<not> use C<&len>).  If you do
not care about what the length of the key is, you may use the global
variable C<PL_na>, though this is rather less efficient than using a local
variable.  Remember though, that hash keys in perl are free to contain
embedded nulls, so using C<strlen()> or similar is not a good way to find
the length of hash keys. This is very similar to the C<SvPV()> macro
described elsewhere in this document.

=for apidoc Am|SV*|HeSVKEY|HE* he
Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not
contain an C<SV*> key.

=for apidoc Am|SV*|HeSVKEY_force|HE* he
Returns the key as an C<SV*>.  Will create and return a temporary mortal
C<SV*> if the hash entry contains only a C<char*> key.

=for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
Sets the key to a given C<SV*>, taking care to set the appropriate flags to
indicate the presence of an C<SV*> key, and returns the same
C<SV*>.

=cut
*/

/* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
#define HEf_SVKEY	-2	/* hent_key is an SV* */


#define Nullhv Null(HV*)
#define HvARRAY(hv)	(*(HE***)&((XPVHV*)  SvANY(hv))->xhv_array)
#define HvFILL(hv)	((XPVHV*)  SvANY(hv))->xhv_fill
#define HvMAX(hv)	((XPVHV*)  SvANY(hv))->xhv_max
#define HvRITER(hv)	((XPVHV*)  SvANY(hv))->xhv_riter
#define HvEITER(hv)	((XPVHV*)  SvANY(hv))->xhv_eiter
#define HvPMROOT(hv)	((XPVHV*)  SvANY(hv))->xhv_pmroot
#define HvNAME(hv)	((XPVHV*)  SvANY(hv))->xhv_name

/* the number of keys (including any placeholers) */
#define XHvTOTALKEYS(xhv)	((xhv)->xhv_keys)

/* The number of placeholders in the enumerated-keys hash */
#define XHvPLACEHOLDERS(xhv)	((xhv)->xhv_placeholders)

/* the number of keys that exist() (i.e. excluding placeholders) */
#define XHvUSEDKEYS(xhv)      (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv))

/*
 * HvKEYS gets the number of keys that actually exist(), and is provided
 * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
 * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
 */
#define HvKEYS(hv)		XHvUSEDKEYS((XPVHV*)  SvANY(hv))
#define HvUSEDKEYS(hv)		XHvUSEDKEYS((XPVHV*)  SvANY(hv))
#define HvTOTALKEYS(hv)		XHvTOTALKEYS((XPVHV*)  SvANY(hv))
#define HvPLACEHOLDERS(hv)	XHvPLACEHOLDERS((XPVHV*)  SvANY(hv))

#define HvSHAREKEYS(hv)		(SvFLAGS(hv) & SVphv_SHAREKEYS)
#define HvSHAREKEYS_on(hv)	(SvFLAGS(hv) |= SVphv_SHAREKEYS)
#define HvSHAREKEYS_off(hv)	(SvFLAGS(hv) &= ~SVphv_SHAREKEYS)

/* This is an optimisation flag. It won't be set if all hash keys have a 0
 * flag. Currently the only flags relate to utf8.
 * Hence it won't be set if all keys are 8 bit only. It will be set if any key
 * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
 * when retrieved during iteration. It may still be set when there are no longer
 * any utf8 keys.
 * See HVhek_ENABLEHVKFLAGS for the trigger.
 */
#define HvHASKFLAGS(hv)		(SvFLAGS(hv) & SVphv_HASKFLAGS)
#define HvHASKFLAGS_on(hv)	(SvFLAGS(hv) |= SVphv_HASKFLAGS)
#define HvHASKFLAGS_off(hv)	(SvFLAGS(hv) &= ~SVphv_HASKFLAGS)

#define HvLAZYDEL(hv)		(SvFLAGS(hv) & SVphv_LAZYDEL)
#define HvLAZYDEL_on(hv)	(SvFLAGS(hv) |= SVphv_LAZYDEL)
#define HvLAZYDEL_off(hv)	(SvFLAGS(hv) &= ~SVphv_LAZYDEL)

#define HvREHASH(hv)		(SvFLAGS(hv) & SVphv_REHASH)
#define HvREHASH_on(hv)		(SvFLAGS(hv) |= SVphv_REHASH)
#define HvREHASH_off(hv)	(SvFLAGS(hv) &= ~SVphv_REHASH)

/* Maybe amagical: */
/* #define HV_AMAGICmb(hv)      (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */

#define HV_AMAGIC(hv)        (SvFLAGS(hv) &   SVpgv_AM)
#define HV_AMAGIC_on(hv)     (SvFLAGS(hv) |=  SVpgv_AM)
#define HV_AMAGIC_off(hv)    (SvFLAGS(hv) &= ~SVpgv_AM)

/*
#define HV_AMAGICbad(hv)     (SvFLAGS(hv) & SVpgv_badAM)
#define HV_badAMAGIC_on(hv)  (SvFLAGS(hv) |= SVpgv_badAM)
#define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
*/

#define Nullhe Null(HE*)
#define HeNEXT(he)		(he)->hent_next
#define HeKEY_hek(he)		(he)->hent_hek
#define HeKEY(he)		HEK_KEY(HeKEY_hek(he))
#define HeKEY_sv(he)		(*(SV**)HeKEY(he))
#define HeKLEN(he)		HEK_LEN(HeKEY_hek(he))
#define HeKUTF8(he)  HEK_UTF8(HeKEY_hek(he))
#define HeKWASUTF8(he)  HEK_WASUTF8(HeKEY_hek(he))
#define HeKREHASH(he)  HEK_REHASH(HeKEY_hek(he))
#define HeKLEN_UTF8(he)  (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
#define HeKFLAGS(he)  HEK_FLAGS(HeKEY_hek(he))
#define HeVAL(he)		(he)->hent_val
#define HeHASH(he)		HEK_HASH(HeKEY_hek(he))
#define HePV(he,lp)		((HeKLEN(he) == HEf_SVKEY) ?		\
				 SvPV(HeKEY_sv(he),lp) :		\
				 (((lp = HeKLEN(he)) >= 0) ?		\
				  HeKEY(he) : Nullch))

#define HeSVKEY(he)		((HeKEY(he) && 				\
				  HeKLEN(he) == HEf_SVKEY) ?		\
				 HeKEY_sv(he) : Nullsv)

#define HeSVKEY_force(he)	(HeKEY(he) ?				\
				 ((HeKLEN(he) == HEf_SVKEY) ?		\
				  HeKEY_sv(he) :			\
				  sv_2mortal(newSVpvn(HeKEY(he),	\
						     HeKLEN(he)))) :	\
				 &PL_sv_undef)
#define HeSVKEY_set(he,sv)	((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))

#define Nullhek Null(HEK*)
#define HEK_BASESIZE		STRUCT_OFFSET(HEK, hek_key[0])
#define HEK_HASH(hek)		(hek)->hek_hash
#define HEK_LEN(hek)		(hek)->hek_len
#define HEK_KEY(hek)		(hek)->hek_key
#define HEK_FLAGS(hek)	(*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1))

#define HVhek_UTF8	0x01 /* Key is utf8 encoded. */
#define HVhek_WASUTF8	0x02 /* Key is bytes here, but was supplied as utf8. */
#define HVhek_REHASH	0x04 /* This key is in an hv using a custom HASH . */
#define HVhek_FREEKEY	0x100 /* Internal flag to say key is malloc()ed.  */
#define HVhek_PLACEHOLD	0x200 /* Internal flag to create placeholder.
                               * (may change, but Storable is a core module) */
#define HVhek_MASK	0xFF

/* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as
   HVhek_REHASH is only needed because the rehash flag has to be duplicated
   into all keys as hv_iternext has no access to the hash flags. At this
   point Storable's tests get upset, because sometimes hashes are "keyed"
   and sometimes not, depending on the order of data insertion, and whether
   it triggered rehashing. So currently HVhek_REHAS is exempt.
*/
   
#define HVhek_ENABLEHVKFLAGS	(HVhek_MASK - HVhek_REHASH)

#define HEK_UTF8(hek)		(HEK_FLAGS(hek) & HVhek_UTF8)
#define HEK_UTF8_on(hek)	(HEK_FLAGS(hek) |= HVhek_UTF8)
#define HEK_UTF8_off(hek)	(HEK_FLAGS(hek) &= ~HVhek_UTF8)
#define HEK_WASUTF8(hek)	(HEK_FLAGS(hek) & HVhek_WASUTF8)
#define HEK_WASUTF8_on(hek)	(HEK_FLAGS(hek) |= HVhek_WASUTF8)
#define HEK_WASUTF8_off(hek)	(HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
#define HEK_REHASH(hek)		(HEK_FLAGS(hek) & HVhek_REHASH)
#define HEK_REHASH_on(hek)	(HEK_FLAGS(hek) |= HVhek_REHASH)

/* calculate HV array allocation */
#if defined(STRANGE_MALLOC) || defined(MYMALLOC)
#  define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
#else
#  define MALLOC_OVERHEAD 16
#  define PERL_HV_ARRAY_ALLOC_BYTES(size) \
			(((size) < 64)					\
			 ? (size) * sizeof(HE*)				\
			 : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
#endif

/* Flags for hv_iternext_flags.  */
#define HV_ITERNEXT_WANTPLACEHOLDERS	0x01	/* Don't skip placeholders.  */

/* available as a function in hv.c */
#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
#define sharepvn(sv, len, hash)	     Perl_sharepvn(sv, len, hash)
Commit	Line	Data
a0d0e21e	1	/* hv.h
79072805	2	*
4bb101f2 JH	3	* Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
4bb101f2 JH	4	* 2000, 2001, 2002, by Larry Wall and others
79072805 LW	5	*
	6	* You may distribute under the terms of either the GNU General Public
	7	* License or the Artistic License, as specified in the README file.
	8	*
79072805 LW	9	*/
79072805 LW	10
5cbe4eec	11	/* typedefs to eliminate some typing */
79072805	12	typedef struct he HE;
ff68c719	13	typedef struct hek HEK;
79072805	14
5cbe4eec	15	/* entry in hash value chain */
79072805	16	struct he {
5cbe4eec MLF	17	HE hent_next; / next entry in chain */
	18	HEK hent_hek; / hash key */
	19	SV hent_val; / scalar value that was hashed */
bbce6d69	20	};
bbce6d69	21
5cbe4eec	22	/* hash key -- defined separately for use as shared pointer */
ff68c719	23	struct hek {
5cbe4eec MLF	24	U32 hek_hash; /* hash of key */
	25	I32 hek_len; /* length of hash key */
	26	char hek_key[1]; /* variable-length hash key */
e05949c7	27	/* the hash-key is \0-terminated */
1e54db1a JH	28	/* after the \0 there is a byte for flags, such as whether the key
1e54db1a JH	29	is UTF-8 */
79072805 LW	30	};
79072805 LW	31
5cbe4eec	32	/* hash structure: */
6ee623d5	33	/* This structure must match the beginning of struct xpvmg in sv.h. */
79072805	34	struct xpvhv {
463ee0b2 LW	35	char * xhv_array; /* pointer to malloced string */
	36	STRLEN xhv_fill; /* how full xhv_array currently is */
	37	STRLEN xhv_max; /* subscript of last element of xhv_array */
6ee623d5	38	IV xhv_keys; /* how many elements in the array */
65202027	39	NV xnv_nv; /* numeric value, if any */
8aacddc1	40	#define xhv_placeholders xnv_nv
79072805 LW	41	MAGIC* xmg_magic; /* magic for scalar array */
	42	HV* xmg_stash; /* class package */
	43
79072805 LW	44	I32 xhv_riter; /* current root of iterator */
	45	HE xhv_eiter; / current entry of iterator */
	46	PMOP xhv_pmroot; / list of pm's for this package */
	47	char xhv_name; / name, if a symbol table */
79072805 LW	48	};
79072805 LW	49
5cbe4eec	50	/* hash a key */
5afd6d42 JH	51	/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins
	52	* from requirements by Colin Plumb.
	53	* (http://burtleburtle.net/bob/hash/doobs.html) */
	54	/* The use of a temporary pointer and the casting games
	55	* is needed to serve the dual purposes of
	56	* (a) the hashed data being interpreted as "unsigned char" (new since 5.8,
	57	* a "char" can be either signed or signed, depending on the compiler)
	58	* (b) catering for old code that uses a "char"
830b38bd	59	*
504f80c1 JH	60	* The "hash seed" feature was added in Perl 5.8.1 to perturb the results
504f80c1 JH	61	* to avoid "algorithmic complexity attacks".
830b38bd JH	62	*
	63	* If USE_HASH_SEED is defined, hash randomisation is done by default
	64	* If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done
	65	* only if the environment variable PERL_HASH_SEED is set.
	66	* For maximal control, one can define PERL_HASH_SEED.
	67	* (see also erl.c:perl_parse()).
5afd6d42	68	*/
830b38bd JH	69	#ifndef PERL_HASH_SEED
	70	# if defined(USE_HASH_SEED) \|\| defined(USE_HASH_SEED_EXPLICIT)
	71	# define PERL_HASH_SEED PL_hash_seed
	72	# else
	73	# define PERL_HASH_SEED 0
	74	# endif
504f80c1	75	#endif
bf6bd887	76	#define PERL_HASH(hash,str,len) \
bf6bd887	77	STMT_START { \
5afd6d42 JH	78	register const char *s_PeRlHaSh_tmp = str; \
5afd6d42 JH	79	register const unsigned char s_PeRlHaSh = (const unsigned char )s_PeRlHaSh_tmp; \
bf6bd887	80	register I32 i_PeRlHaSh = len; \
504f80c1	81	register U32 hash_PeRlHaSh = PERL_HASH_SEED; \
a6fe520e MLF	82	while (i_PeRlHaSh--) { \
	83	hash_PeRlHaSh += *s_PeRlHaSh++; \
	84	hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
	85	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
	86	} \
	87	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
	88	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
4fee5c71	89	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
bf6bd887	90	} STMT_END
bf6bd887	91
4b5190b5 NC	92	#ifdef PERL_IN_HV_C
	93	#define PERL_HASH_INTERNAL(hash,str,len) \
	94	STMT_START { \
	95	register const char *s_PeRlHaSh_tmp = str; \
	96	register const unsigned char s_PeRlHaSh = (const unsigned char )s_PeRlHaSh_tmp; \
	97	register I32 i_PeRlHaSh = len; \
	98	register U32 hash_PeRlHaSh = PL_new_hash_seed; \
	99	while (i_PeRlHaSh--) { \
	100	hash_PeRlHaSh += *s_PeRlHaSh++; \
	101	hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
	102	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
	103	} \
	104	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
	105	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
	106	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
	107	} STMT_END
	108	#endif
	109
954c1994	110	/*
ccfc67b7 JH	111	=head1 Hash Manipulation Functions
ccfc67b7 JH	112
954c1994 GS	113	=for apidoc AmU\|\|HEf_SVKEY
954c1994 GS	114	This flag, used in the length slot of hash entries and magic structures,
d1be9408	115	specifies the structure contains an C<SV> pointer where a C<char> pointer
954c1994 GS	116	is to be expected. (For information only--not to be used).
954c1994 GS	117
ccfc67b7 JH	118	=head1 Handy Values
ccfc67b7 JH	119
954c1994 GS	120	=for apidoc AmU\|\|Nullhv
	121	Null HV pointer.
	122
ccfc67b7 JH	123	=head1 Hash Manipulation Functions
ccfc67b7 JH	124
954c1994 GS	125	=for apidoc Am\|char\|HvNAME\|HV stash
	126	Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>.
	127
	128	=for apidoc Am\|void\|HeKEY\|HE he
	129	Returns the actual pointer stored in the key slot of the hash entry. The
	130	pointer may be either C<char> or C<SV>, depending on the value of
	131	C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are
	132	usually preferable for finding the value of a key.
	133
	134	=for apidoc Am\|STRLEN\|HeKLEN\|HE* he
	135	If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
	136	holds an C<SV*> key. Otherwise, holds the actual length of the key. Can
	137	be assigned to. The C<HePV()> macro is usually preferable for finding key
	138	lengths.
	139
	140	=for apidoc Am\|SV\|HeVAL\|HE he
	141	Returns the value slot (type C<SV*>) stored in the hash entry.
	142
	143	=for apidoc Am\|U32\|HeHASH\|HE* he
	144	Returns the computed hash stored in the hash entry.
	145
	146	=for apidoc Am\|char\|HePV\|HE he\|STRLEN len
	147	Returns the key slot of the hash entry as a C<char*> value, doing any
	148	necessary dereferencing of possibly C<SV*> keys. The length of the string
	149	is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do
	150	not care about what the length of the key is, you may use the global
	151	variable C<PL_na>, though this is rather less efficient than using a local
	152	variable. Remember though, that hash keys in perl are free to contain
	153	embedded nulls, so using C<strlen()> or similar is not a good way to find
	154	the length of hash keys. This is very similar to the C<SvPV()> macro
	155	described elsewhere in this document.
	156
	157	=for apidoc Am\|SV\|HeSVKEY\|HE he
	158	Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not
	159	contain an C<SV*> key.
	160
	161	=for apidoc Am\|SV\|HeSVKEY_force\|HE he
	162	Returns the key as an C<SV*>. Will create and return a temporary mortal
	163	C<SV> if the hash entry contains only a C<char> key.
	164
	165	=for apidoc Am\|SV\|HeSVKEY_set\|HE he\|SV* sv
	166	Sets the key to a given C<SV*>, taking care to set the appropriate flags to
	167	indicate the presence of an C<SV*> key, and returns the same
	168	C<SV*>.
	169
	170	=cut
	171	*/
bf6bd887	172
bf5b86ae	173	/* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
d1be9408	174	#define HEf_SVKEY -2 /* hent_key is an SV* */
bf6bd887	175
bf6bd887	176
79072805	177	#define Nullhv Null(HV*)
4efcf9a2	178	#define HvARRAY(hv) ((HE*)&((XPVHV) SvANY(hv))->xhv_array)
79072805	179	#define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill
463ee0b2	180	#define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max
79072805 LW	181	#define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter
	182	#define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter
	183	#define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot
	184	#define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name
a0d0e21e	185
8aacddc1 NIS	186	/* the number of keys (including any placeholers) */
	187	#define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys)
	188
	189	/* The number of placeholders in the enumerated-keys hash */
205c8ad3	190	#define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders)
8aacddc1	191
dd2710a1 VK	192	/* the number of keys that exist() (i.e. excluding placeholders) */
dd2710a1 VK	193	#define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv))
8aacddc1 NIS	194
	195	/*
	196	* HvKEYS gets the number of keys that actually exist(), and is provided
	197	* for backwards compatibility with old XS code. The core uses HvUSEDKEYS
	198	* (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
	199	*/
	200	#define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
	201	#define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
	202	#define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv))
	203	#define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv))
	204
bf6bd887	205	#define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS)
	206	#define HvSHAREKEYS_on(hv) (SvFLAGS(hv) \|= SVphv_SHAREKEYS)
	207	#define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
	208
19692e8d NC	209	/* This is an optimisation flag. It won't be set if all hash keys have a 0
	210	* flag. Currently the only flags relate to utf8.
	211	* Hence it won't be set if all keys are 8 bit only. It will be set if any key
	212	* is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
	213	* when retrieved during iteration. It may still be set when there are no longer
	214	* any utf8 keys.
fdcd69b6	215	* See HVhek_ENABLEHVKFLAGS for the trigger.
19692e8d NC	216	*/
	217	#define HvHASKFLAGS(hv) (SvFLAGS(hv) & SVphv_HASKFLAGS)
	218	#define HvHASKFLAGS_on(hv) (SvFLAGS(hv) \|= SVphv_HASKFLAGS)
	219	#define HvHASKFLAGS_off(hv) (SvFLAGS(hv) &= ~SVphv_HASKFLAGS)
574c8022	220
bf5b86ae GS	221	#define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL)
	222	#define HvLAZYDEL_on(hv) (SvFLAGS(hv) \|= SVphv_LAZYDEL)
	223	#define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL)
	224
4b5190b5 NC	225	#define HvREHASH(hv) (SvFLAGS(hv) & SVphv_REHASH)
	226	#define HvREHASH_on(hv) (SvFLAGS(hv) \|= SVphv_REHASH)
	227	#define HvREHASH_off(hv) (SvFLAGS(hv) &= ~SVphv_REHASH)
	228
a0d0e21e LW	229	/* Maybe amagical: */
	230	/* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM \| SVpgv_AM)) */
	231
	232	#define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM)
	233	#define HV_AMAGIC_on(hv) (SvFLAGS(hv) \|= SVpgv_AM)
	234	#define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM)
	235
	236	/*
	237	#define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM)
	238	#define HV_badAMAGIC_on(hv) (SvFLAGS(hv) \|= SVpgv_badAM)
	239	#define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
	240	*/
bf6bd887	241
	242	#define Nullhe Null(HE*)
	243	#define HeNEXT(he) (he)->hent_next
ff68c719	244	#define HeKEY_hek(he) (he)->hent_hek
ff68c719	245	#define HeKEY(he) HEK_KEY(HeKEY_hek(he))
bbce6d69	246	#define HeKEY_sv(he) ((SV*)HeKEY(he))
ff68c719	247	#define HeKLEN(he) HEK_LEN(HeKEY_hek(he))
da58a35d	248	#define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he))
19692e8d	249	#define HeKWASUTF8(he) HEK_WASUTF8(HeKEY_hek(he))
4b5190b5	250	#define HeKREHASH(he) HEK_REHASH(HeKEY_hek(he))
da58a35d	251	#define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
19692e8d	252	#define HeKFLAGS(he) HEK_FLAGS(HeKEY_hek(he))
bf6bd887	253	#define HeVAL(he) (he)->hent_val
ff68c719	254	#define HeHASH(he) HEK_HASH(HeKEY_hek(he))
1e422769	255	#define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \
	256	SvPV(HeKEY_sv(he),lp) : \
	257	(((lp = HeKLEN(he)) >= 0) ? \
	258	HeKEY(he) : Nullch))
	259
bbce6d69	260	#define HeSVKEY(he) ((HeKEY(he) && \
	261	HeKLEN(he) == HEf_SVKEY) ? \
	262	HeKEY_sv(he) : Nullsv)
	263
	264	#define HeSVKEY_force(he) (HeKEY(he) ? \
	265	((HeKLEN(he) == HEf_SVKEY) ? \
	266	HeKEY_sv(he) : \
79cb57f6	267	sv_2mortal(newSVpvn(HeKEY(he), \
bbce6d69	268	HeKLEN(he)))) : \
3280af22	269	&PL_sv_undef)
1e422769	270	#define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
bbce6d69	271
ff68c719	272	#define Nullhek Null(HEK*)
71be2cbc	273	#define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0])
ff68c719	274	#define HEK_HASH(hek) (hek)->hek_hash
	275	#define HEK_LEN(hek) (hek)->hek_len
	276	#define HEK_KEY(hek) (hek)->hek_key
19692e8d NC	277	#define HEK_FLAGS(hek) (((unsigned char )(HEK_KEY(hek))+HEK_LEN(hek)+1))
	278
	279	#define HVhek_UTF8 0x01 /* Key is utf8 encoded. */
	280	#define HVhek_WASUTF8 0x02 /* Key is bytes here, but was supplied as utf8. */
4b5190b5	281	#define HVhek_REHASH 0x04 /* This key is in an hv using a custom HASH . */
19692e8d	282	#define HVhek_FREEKEY 0x100 /* Internal flag to say key is malloc()ed. */
e16e2ff8 NC	283	#define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder.
e16e2ff8 NC	284	* (may change, but Storable is a core module) */
19692e8d NC	285	#define HVhek_MASK 0xFF
19692e8d NC	286
fdcd69b6 NC	287	/* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as
	288	HVhek_REHASH is only needed because the rehash flag has to be duplicated
	289	into all keys as hv_iternext has no access to the hash flags. At this
	290	point Storable's tests get upset, because sometimes hashes are "keyed"
	291	and sometimes not, depending on the order of data insertion, and whether
	292	it triggered rehashing. So currently HVhek_REHAS is exempt.
	293	*/
	294
	295	#define HVhek_ENABLEHVKFLAGS (HVhek_MASK - HVhek_REHASH)
	296
19692e8d NC	297	#define HEK_UTF8(hek) (HEK_FLAGS(hek) & HVhek_UTF8)
	298	#define HEK_UTF8_on(hek) (HEK_FLAGS(hek) \|= HVhek_UTF8)
	299	#define HEK_UTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_UTF8)
	300	#define HEK_WASUTF8(hek) (HEK_FLAGS(hek) & HVhek_WASUTF8)
	301	#define HEK_WASUTF8_on(hek) (HEK_FLAGS(hek) \|= HVhek_WASUTF8)
	302	#define HEK_WASUTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
4b5190b5 NC	303	#define HEK_REHASH(hek) (HEK_FLAGS(hek) & HVhek_REHASH)
4b5190b5 NC	304	#define HEK_REHASH_on(hek) (HEK_FLAGS(hek) \|= HVhek_REHASH)
d18c6117	305
5cbe4eec	306	/* calculate HV array allocation */
d18c6117 GS	307	#if defined(STRANGE_MALLOC) \|\| defined(MYMALLOC)
	308	# define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
	309	#else
	310	# define MALLOC_OVERHEAD 16
	311	# define PERL_HV_ARRAY_ALLOC_BYTES(size) \
	312	(((size) < 64) \
	313	? (size) * sizeof(HE*) \
	314	: (size) * sizeof(HE) 2 - MALLOC_OVERHEAD)
	315	#endif
37d85e3a	316
e16e2ff8 NC	317	/* Flags for hv_iternext_flags. */
	318	#define HV_ITERNEXT_WANTPLACEHOLDERS 0x01 /* Don't skip placeholders. */
	319
37d85e3a JH	320	/* available as a function in hv.c */
	321	#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
	322	#define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)