[perl5.git] / hv.h

/*    hv.h
 *
 *    Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
 *    2000, 2001, 2002, 2005, 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.
 *
 */

/* entry in hash value chain */
struct he {
    /* Keep hent_next first in this structure, because sv_free_arenas take
       advantage of this to share code between the he arenas and the SV
       body arenas  */
    HE		*hent_next;	/* next entry in chain */
    HEK		*hent_hek;	/* hash key */
    union {
	SV	*hent_val;	/* scalar value that was hashed */
	Size_t	hent_refcount;	/* references for this shared hash key */
    } he_valu;
};

/* 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 */
};

struct shared_he {
    struct he shared_he_he;
    struct hek shared_he_hek;
};

/* Subject to change.
   Don't access this directly.
*/
struct xpvhv_aux {
    HEK		*xhv_name;	/* name, if a symbol table */
    AV		*xhv_backreferences; /* back references for weak references */
    HE		*xhv_eiter;	/* current entry of iterator */
    I32		xhv_riter;	/* current root of iterator */
};

/* hash structure: */
/* This structure must match the beginning of struct xpvmg in sv.h. */
struct xpvhv {
    union {
	NV	xnv_nv;		/* numeric value, if any */
	HV *	xgv_stash;
    }		xnv_u;
    STRLEN	xhv_fill;	/* how full xhv_array currently is */
    STRLEN	xhv_max;	/* subscript of last element of xhv_array */
    union {
	IV	xivu_iv;	/* integer value or pv offset */
	UV	xivu_uv;
	void *	xivu_p1;
	I32	xivu_i32;
	HEK *	xivu_namehek;
    }		xiv_u;
    union {
	MAGIC*	xmg_magic;	/* linked list of magicalness */
	HV*	xmg_ourstash;	/* Stash for our (when SvPAD_OUR is true) */
    } xmg_u;
    HV*		xmg_stash;	/* class package */
};

#define xhv_keys xiv_u.xivu_iv

#if 0
typedef struct xpvhv xpvhv_allocated;
#else
typedef struct {
    STRLEN	xhv_fill;	/* how full xhv_array currently is */
    STRLEN	xhv_max;	/* subscript of last element of xhv_array */
    union {
	IV	xivu_iv;	/* integer value or pv offset */
	UV	xivu_uv;
	void *	xivu_p1;
	I32	xivu_i32;
	HEK *	xivu_namehek;
    }		xiv_u;
    union {
	MAGIC*	xmg_magic;	/* linked list of magicalness */
	HV*	xmg_ourstash;	/* Stash for our (when SvPAD_OUR is true) */
    } xmg_u;
    HV*		xmg_stash;	/* class package */
} xpvhv_allocated;
#endif

/* 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 unsigned, 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 perl.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 * const 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

/* Only hv.c and mod_perl should be doing this.  */
#ifdef PERL_HASH_INTERNAL_ACCESS
#define PERL_HASH_INTERNAL(hash,str,len) \
     STMT_START	{ \
	register const char * const 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_rehash_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, or NULL if C<stash> isn't 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<NULL> 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)	((hv)->sv_u.svu_hash)
#define HvFILL(hv)	((XPVHV*)  SvANY(hv))->xhv_fill
#define HvMAX(hv)	((XPVHV*)  SvANY(hv))->xhv_max
/* This quite intentionally does no flag checking first. That's your
   responsibility.  */
#define HvAUX(hv)	((struct xpvhv_aux*)&(HvARRAY(hv)[HvMAX(hv)+1]))
#define HvRITER(hv)	(*Perl_hv_riter_p(aTHX_ (HV*)(hv)))
#define HvEITER(hv)	(*Perl_hv_eiter_p(aTHX_ (HV*)(hv)))
#define HvRITER_set(hv,r)	Perl_hv_riter_set(aTHX_ (HV*)(hv), r)
#define HvEITER_set(hv,e)	Perl_hv_eiter_set(aTHX_ (HV*)(hv), e)
#define HvRITER_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_riter : -1)
#define HvEITER_get(hv)	(SvOOK(hv) ? HvAUX(hv)->xhv_eiter : 0)
#define HvNAME(hv)	HvNAME_get(hv)
/* FIXME - all of these should use a UTF8 aware API, which should also involve
   getting the length. */
/* This macro may go away without notice.  */
#define HvNAME_HEK(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_name : 0)
#define HvNAME_get(hv)	((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
			 ? HEK_KEY(HvAUX(hv)->xhv_name) : 0)
#define HvNAMELEN_get(hv)	((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
				 ? HEK_LEN(HvAUX(hv)->xhv_name) : 0)

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

/*
 * 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)		HvUSEDKEYS(hv)
#define HvUSEDKEYS(hv)		(HvTOTALKEYS(hv) - HvPLACEHOLDERS_get(hv))
#define HvTOTALKEYS(hv)		XHvTOTALKEYS((XPVHV*)  SvANY(hv))
#define HvPLACEHOLDERS(hv)	(*Perl_hv_placeholders_p(aTHX_ (HV*)hv))
#define HvPLACEHOLDERS_get(hv)	(SvMAGIC(hv) ? Perl_hv_placeholders_get(aTHX_ (HV*)hv) : 0)
#define HvPLACEHOLDERS_set(hv,p)	Perl_hv_placeholders_set(aTHX_ (HV*)hv, p)

#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)->he_valu.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) : NULL))

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

#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 */
#ifndef PERL_USE_LARGE_HV_ALLOC
/* Default to allocating the correct size - default to assuming that malloc()
   is not broken and is efficient at allocating blocks sized at powers-of-two.
*/   
#  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.  */

#define hv_iternext(hv)	hv_iternext_flags(hv, 0)
#define hv_magic(hv, gv, how) sv_magic((SV*)(hv), (SV*)(gv), how, NULL, 0)

/* 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)

#define share_hek_hek(hek)						\
    (++(((struct shared_he *)(((char *)hek)				\
			      - STRUCT_OFFSET(struct shared_he,		\
					      shared_he_hek)))		\
	->shared_he_he.he_valu.hent_refcount),				\
     hek)

/*
 * Local variables:
 * c-indentation-style: bsd
 * c-basic-offset: 4
 * indent-tabs-mode: t
 * End:
 *
 * ex: set ts=8 sts=4 sw=4 noet:
 */
Commit	Line	Data
a0d0e21e	1	/* hv.h
79072805	2	*
4bb101f2	3	* Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
1d325971	4	* 2000, 2001, 2002, 2005, 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	/* entry in hash value chain */
79072805	12	struct he {
6f51351d NC	13	/* Keep hent_next first in this structure, because sv_free_arenas take
	14	advantage of this to share code between the he arenas and the SV
	15	body arenas */
5cbe4eec MLF	16	HE hent_next; / next entry in chain */
5cbe4eec MLF	17	HEK hent_hek; / hash key */
de616631 NC	18	union {
	19	SV hent_val; / scalar value that was hashed */
	20	Size_t hent_refcount; /* references for this shared hash key */
	21	} he_valu;
bbce6d69	22	};
bbce6d69	23
5cbe4eec	24	/* hash key -- defined separately for use as shared pointer */
ff68c719	25	struct hek {
5cbe4eec MLF	26	U32 hek_hash; /* hash of key */
	27	I32 hek_len; /* length of hash key */
	28	char hek_key[1]; /* variable-length hash key */
e05949c7	29	/* the hash-key is \0-terminated */
1e54db1a JH	30	/* after the \0 there is a byte for flags, such as whether the key
1e54db1a JH	31	is UTF-8 */
79072805 LW	32	};
79072805 LW	33
cbae3960 NC	34	struct shared_he {
	35	struct he shared_he_he;
	36	struct hek shared_he_hek;
	37	};
bfcb3514 NC	38
	39	/* Subject to change.
	40	Don't access this directly.
	41	*/
	42	struct xpvhv_aux {
7423f6db	43	HEK xhv_name; / name, if a symbol table */
86f55936	44	AV xhv_backreferences; / back references for weak references */
bfcb3514 NC	45	HE xhv_eiter; / current entry of iterator */
	46	I32 xhv_riter; /* current root of iterator */
	47	};
	48
5cbe4eec	49	/* hash structure: */
6ee623d5	50	/* This structure must match the beginning of struct xpvmg in sv.h. */
79072805	51	struct xpvhv {
58430790 NC	52	union {
	53	NV xnv_nv; /* numeric value, if any */
	54	HV * xgv_stash;
	55	} xnv_u;
463ee0b2 LW	56	STRLEN xhv_fill; /* how full xhv_array currently is */
463ee0b2 LW	57	STRLEN xhv_max; /* subscript of last element of xhv_array */
e4305a63	58	union {
311a25d9 NC	59	IV xivu_iv; /* integer value or pv offset */
	60	UV xivu_uv;
	61	void * xivu_p1;
69ecfd12 NC	62	I32 xivu_i32;
69ecfd12 NC	63	HEK * xivu_namehek;
311a25d9	64	} xiv_u;
e736a858 NC	65	union {
	66	MAGIC* xmg_magic; /* linked list of magicalness */
	67	HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */
	68	} xmg_u;
79072805	69	HV* xmg_stash; /* class package */
79072805 LW	70	};
79072805 LW	71
311a25d9	72	#define xhv_keys xiv_u.xivu_iv
e4305a63	73
c5f87f51	74	#if 0
59813432	75	typedef struct xpvhv xpvhv_allocated;
9f1501b2 NC	76	#else
	77	typedef struct {
	78	STRLEN xhv_fill; /* how full xhv_array currently is */
	79	STRLEN xhv_max; /* subscript of last element of xhv_array */
	80	union {
311a25d9 NC	81	IV xivu_iv; /* integer value or pv offset */
	82	UV xivu_uv;
	83	void * xivu_p1;
69ecfd12 NC	84	I32 xivu_i32;
69ecfd12 NC	85	HEK * xivu_namehek;
311a25d9	86	} xiv_u;
e736a858 NC	87	union {
	88	MAGIC* xmg_magic; /* linked list of magicalness */
	89	HV* xmg_ourstash; /* Stash for our (when SvPAD_OUR is true) */
	90	} xmg_u;
9f1501b2 NC	91	HV* xmg_stash; /* class package */
	92	} xpvhv_allocated;
	93	#endif
e4305a63	94
5cbe4eec	95	/* hash a key */
5afd6d42 JH	96	/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins
	97	* from requirements by Colin Plumb.
	98	* (http://burtleburtle.net/bob/hash/doobs.html) */
	99	/* The use of a temporary pointer and the casting games
	100	* is needed to serve the dual purposes of
	101	* (a) the hashed data being interpreted as "unsigned char" (new since 5.8,
df805c3e	102	* a "char" can be either signed or unsigned, depending on the compiler)
5afd6d42	103	* (b) catering for old code that uses a "char"
830b38bd	104	*
504f80c1 JH	105	* The "hash seed" feature was added in Perl 5.8.1 to perturb the results
504f80c1 JH	106	* to avoid "algorithmic complexity attacks".
830b38bd JH	107	*
	108	* If USE_HASH_SEED is defined, hash randomisation is done by default
	109	* If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done
	110	* only if the environment variable PERL_HASH_SEED is set.
	111	* For maximal control, one can define PERL_HASH_SEED.
90ce55a1	112	* (see also perl.c:perl_parse()).
5afd6d42	113	*/
830b38bd JH	114	#ifndef PERL_HASH_SEED
	115	# if defined(USE_HASH_SEED) \|\| defined(USE_HASH_SEED_EXPLICIT)
	116	# define PERL_HASH_SEED PL_hash_seed
	117	# else
	118	# define PERL_HASH_SEED 0
	119	# endif
504f80c1	120	#endif
bf6bd887	121	#define PERL_HASH(hash,str,len) \
bf6bd887	122	STMT_START { \
0bd48802	123	register const char * const s_PeRlHaSh_tmp = str; \
5afd6d42	124	register const unsigned char s_PeRlHaSh = (const unsigned char )s_PeRlHaSh_tmp; \
bf6bd887	125	register I32 i_PeRlHaSh = len; \
504f80c1	126	register U32 hash_PeRlHaSh = PERL_HASH_SEED; \
a6fe520e MLF	127	while (i_PeRlHaSh--) { \
	128	hash_PeRlHaSh += *s_PeRlHaSh++; \
	129	hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
	130	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
	131	} \
	132	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
	133	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
4fee5c71	134	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
bf6bd887	135	} STMT_END
bf6bd887	136
3d78eb94 NC	137	/* Only hv.c and mod_perl should be doing this. */
3d78eb94 NC	138	#ifdef PERL_HASH_INTERNAL_ACCESS
4b5190b5 NC	139	#define PERL_HASH_INTERNAL(hash,str,len) \
4b5190b5 NC	140	STMT_START { \
0bd48802	141	register const char * const s_PeRlHaSh_tmp = str; \
4b5190b5 NC	142	register const unsigned char s_PeRlHaSh = (const unsigned char )s_PeRlHaSh_tmp; \
4b5190b5 NC	143	register I32 i_PeRlHaSh = len; \
008fb0c0	144	register U32 hash_PeRlHaSh = PL_rehash_seed; \
4b5190b5 NC	145	while (i_PeRlHaSh--) { \
	146	hash_PeRlHaSh += *s_PeRlHaSh++; \
	147	hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
	148	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
	149	} \
	150	hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
	151	hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
	152	(hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
	153	} STMT_END
	154	#endif
	155
954c1994	156	/*
ccfc67b7 JH	157	=head1 Hash Manipulation Functions
ccfc67b7 JH	158
954c1994 GS	159	=for apidoc AmU\|\|HEf_SVKEY
954c1994 GS	160	This flag, used in the length slot of hash entries and magic structures,
d1be9408	161	specifies the structure contains an C<SV> pointer where a C<char> pointer
954c1994 GS	162	is to be expected. (For information only--not to be used).
954c1994 GS	163
ccfc67b7 JH	164	=head1 Handy Values
ccfc67b7 JH	165
954c1994 GS	166	=for apidoc AmU\|\|Nullhv
	167	Null HV pointer.
	168
ccfc67b7 JH	169	=head1 Hash Manipulation Functions
ccfc67b7 JH	170
954c1994	171	=for apidoc Am\|char\|HvNAME\|HV stash
9282b5fd SH	172	Returns the package name of a stash, or NULL if C<stash> isn't a stash.
9282b5fd SH	173	See C<SvSTASH>, C<CvSTASH>.
954c1994 GS	174
	175	=for apidoc Am\|void\|HeKEY\|HE he
	176	Returns the actual pointer stored in the key slot of the hash entry. The
	177	pointer may be either C<char> or C<SV>, depending on the value of
	178	C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are
	179	usually preferable for finding the value of a key.
	180
	181	=for apidoc Am\|STRLEN\|HeKLEN\|HE* he
	182	If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
	183	holds an C<SV*> key. Otherwise, holds the actual length of the key. Can
	184	be assigned to. The C<HePV()> macro is usually preferable for finding key
	185	lengths.
	186
	187	=for apidoc Am\|SV\|HeVAL\|HE he
	188	Returns the value slot (type C<SV*>) stored in the hash entry.
	189
	190	=for apidoc Am\|U32\|HeHASH\|HE* he
	191	Returns the computed hash stored in the hash entry.
	192
	193	=for apidoc Am\|char\|HePV\|HE he\|STRLEN len
	194	Returns the key slot of the hash entry as a C<char*> value, doing any
	195	necessary dereferencing of possibly C<SV*> keys. The length of the string
	196	is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do
	197	not care about what the length of the key is, you may use the global
	198	variable C<PL_na>, though this is rather less efficient than using a local
	199	variable. Remember though, that hash keys in perl are free to contain
	200	embedded nulls, so using C<strlen()> or similar is not a good way to find
	201	the length of hash keys. This is very similar to the C<SvPV()> macro
	202	described elsewhere in this document.
	203
	204	=for apidoc Am\|SV\|HeSVKEY\|HE he
a0714e2c	205	Returns the key as an C<SV*>, or C<NULL> if the hash entry does not
954c1994 GS	206	contain an C<SV*> key.
	207
	208	=for apidoc Am\|SV\|HeSVKEY_force\|HE he
	209	Returns the key as an C<SV*>. Will create and return a temporary mortal
	210	C<SV> if the hash entry contains only a C<char> key.
	211
	212	=for apidoc Am\|SV\|HeSVKEY_set\|HE he\|SV* sv
	213	Sets the key to a given C<SV*>, taking care to set the appropriate flags to
	214	indicate the presence of an C<SV*> key, and returns the same
	215	C<SV*>.
	216
	217	=cut
	218	*/
bf6bd887	219
bf5b86ae	220	/* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
d1be9408	221	#define HEf_SVKEY -2 /* hent_key is an SV* */
bf6bd887	222
bf6bd887	223
79072805	224	#define Nullhv Null(HV*)
43e6e717	225	#define HvARRAY(hv) ((hv)->sv_u.svu_hash)
79072805	226	#define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill
463ee0b2	227	#define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max
b79f7545 NC	228	/* This quite intentionally does no flag checking first. That's your
	229	responsibility. */
	230	#define HvAUX(hv) ((struct xpvhv_aux*)&(HvARRAY(hv)[HvMAX(hv)+1]))
bfcb3514 NC	231	#define HvRITER(hv) (Perl_hv_riter_p(aTHX_ (HV)(hv)))
	232	#define HvEITER(hv) (Perl_hv_eiter_p(aTHX_ (HV)(hv)))
	233	#define HvRITER_set(hv,r) Perl_hv_riter_set(aTHX_ (HV*)(hv), r)
	234	#define HvEITER_set(hv,e) Perl_hv_eiter_set(aTHX_ (HV*)(hv), e)
b79f7545 NC	235	#define HvRITER_get(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_riter : -1)
b79f7545 NC	236	#define HvEITER_get(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_eiter : 0)
7423f6db	237	#define HvNAME(hv) HvNAME_get(hv)
bfcb3514 NC	238	/* FIXME - all of these should use a UTF8 aware API, which should also involve
bfcb3514 NC	239	getting the length. */
9b9d0b15	240	/* This macro may go away without notice. */
b79f7545 NC	241	#define HvNAME_HEK(hv) (SvOOK(hv) ? HvAUX(hv)->xhv_name : 0)
	242	#define HvNAME_get(hv) ((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
	243	? HEK_KEY(HvAUX(hv)->xhv_name) : 0)
	244	#define HvNAMELEN_get(hv) ((SvOOK(hv) && (HvAUX(hv)->xhv_name)) \
	245	? HEK_LEN(HvAUX(hv)->xhv_name) : 0)
a0d0e21e	246
8aacddc1 NIS	247	/* the number of keys (including any placeholers) */
	248	#define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys)
	249
8aacddc1 NIS	250	/*
	251	* HvKEYS gets the number of keys that actually exist(), and is provided
	252	* for backwards compatibility with old XS code. The core uses HvUSEDKEYS
	253	* (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
	254	*/
ca732855 NC	255	#define HvKEYS(hv) HvUSEDKEYS(hv)
ca732855 NC	256	#define HvUSEDKEYS(hv) (HvTOTALKEYS(hv) - HvPLACEHOLDERS_get(hv))
8aacddc1	257	#define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv))
ca732855 NC	258	#define HvPLACEHOLDERS(hv) (Perl_hv_placeholders_p(aTHX_ (HV)hv))
	259	#define HvPLACEHOLDERS_get(hv) (SvMAGIC(hv) ? Perl_hv_placeholders_get(aTHX_ (HV*)hv) : 0)
	260	#define HvPLACEHOLDERS_set(hv,p) Perl_hv_placeholders_set(aTHX_ (HV*)hv, p)
8aacddc1	261
bf6bd887	262	#define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS)
	263	#define HvSHAREKEYS_on(hv) (SvFLAGS(hv) \|= SVphv_SHAREKEYS)
	264	#define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
	265
19692e8d NC	266	/* This is an optimisation flag. It won't be set if all hash keys have a 0
	267	* flag. Currently the only flags relate to utf8.
	268	* Hence it won't be set if all keys are 8 bit only. It will be set if any key
	269	* is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
	270	* when retrieved during iteration. It may still be set when there are no longer
	271	* any utf8 keys.
fdcd69b6	272	* See HVhek_ENABLEHVKFLAGS for the trigger.
19692e8d NC	273	*/
	274	#define HvHASKFLAGS(hv) (SvFLAGS(hv) & SVphv_HASKFLAGS)
	275	#define HvHASKFLAGS_on(hv) (SvFLAGS(hv) \|= SVphv_HASKFLAGS)
	276	#define HvHASKFLAGS_off(hv) (SvFLAGS(hv) &= ~SVphv_HASKFLAGS)
574c8022	277
bf5b86ae GS	278	#define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL)
	279	#define HvLAZYDEL_on(hv) (SvFLAGS(hv) \|= SVphv_LAZYDEL)
	280	#define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL)
	281
4b5190b5 NC	282	#define HvREHASH(hv) (SvFLAGS(hv) & SVphv_REHASH)
	283	#define HvREHASH_on(hv) (SvFLAGS(hv) \|= SVphv_REHASH)
	284	#define HvREHASH_off(hv) (SvFLAGS(hv) &= ~SVphv_REHASH)
	285
a0d0e21e LW	286	/* Maybe amagical: */
	287	/* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM \| SVpgv_AM)) */
	288
	289	#define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM)
	290	#define HV_AMAGIC_on(hv) (SvFLAGS(hv) \|= SVpgv_AM)
	291	#define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM)
	292
	293	/*
	294	#define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM)
	295	#define HV_badAMAGIC_on(hv) (SvFLAGS(hv) \|= SVpgv_badAM)
	296	#define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
	297	*/
bf6bd887	298
	299	#define Nullhe Null(HE*)
	300	#define HeNEXT(he) (he)->hent_next
ff68c719	301	#define HeKEY_hek(he) (he)->hent_hek
ff68c719	302	#define HeKEY(he) HEK_KEY(HeKEY_hek(he))
bbce6d69	303	#define HeKEY_sv(he) ((SV*)HeKEY(he))
ff68c719	304	#define HeKLEN(he) HEK_LEN(HeKEY_hek(he))
da58a35d	305	#define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he))
19692e8d	306	#define HeKWASUTF8(he) HEK_WASUTF8(HeKEY_hek(he))
4b5190b5	307	#define HeKREHASH(he) HEK_REHASH(HeKEY_hek(he))
da58a35d	308	#define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
19692e8d	309	#define HeKFLAGS(he) HEK_FLAGS(HeKEY_hek(he))
de616631	310	#define HeVAL(he) (he)->he_valu.hent_val
ff68c719	311	#define HeHASH(he) HEK_HASH(HeKEY_hek(he))
1e422769	312	#define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \
	313	SvPV(HeKEY_sv(he),lp) : \
	314	(((lp = HeKLEN(he)) >= 0) ? \
bd61b366	315	HeKEY(he) : NULL))
1e422769	316
bbce6d69	317	#define HeSVKEY(he) ((HeKEY(he) && \
bbce6d69	318	HeKLEN(he) == HEf_SVKEY) ? \
a0714e2c	319	HeKEY_sv(he) : NULL)
bbce6d69	320
	321	#define HeSVKEY_force(he) (HeKEY(he) ? \
	322	((HeKLEN(he) == HEf_SVKEY) ? \
	323	HeKEY_sv(he) : \
79cb57f6	324	sv_2mortal(newSVpvn(HeKEY(he), \
bbce6d69	325	HeKLEN(he)))) : \
3280af22	326	&PL_sv_undef)
1e422769	327	#define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
bbce6d69	328
ff68c719	329	#define Nullhek Null(HEK*)
71be2cbc	330	#define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0])
ff68c719	331	#define HEK_HASH(hek) (hek)->hek_hash
	332	#define HEK_LEN(hek) (hek)->hek_len
	333	#define HEK_KEY(hek) (hek)->hek_key
19692e8d NC	334	#define HEK_FLAGS(hek) (((unsigned char )(HEK_KEY(hek))+HEK_LEN(hek)+1))
	335
	336	#define HVhek_UTF8 0x01 /* Key is utf8 encoded. */
	337	#define HVhek_WASUTF8 0x02 /* Key is bytes here, but was supplied as utf8. */
4b5190b5	338	#define HVhek_REHASH 0x04 /* This key is in an hv using a custom HASH . */
19692e8d	339	#define HVhek_FREEKEY 0x100 /* Internal flag to say key is malloc()ed. */
e16e2ff8 NC	340	#define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder.
e16e2ff8 NC	341	* (may change, but Storable is a core module) */
19692e8d NC	342	#define HVhek_MASK 0xFF
19692e8d NC	343
fdcd69b6 NC	344	/* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as
	345	HVhek_REHASH is only needed because the rehash flag has to be duplicated
	346	into all keys as hv_iternext has no access to the hash flags. At this
	347	point Storable's tests get upset, because sometimes hashes are "keyed"
	348	and sometimes not, depending on the order of data insertion, and whether
	349	it triggered rehashing. So currently HVhek_REHAS is exempt.
	350	*/
	351
	352	#define HVhek_ENABLEHVKFLAGS (HVhek_MASK - HVhek_REHASH)
	353
19692e8d NC	354	#define HEK_UTF8(hek) (HEK_FLAGS(hek) & HVhek_UTF8)
	355	#define HEK_UTF8_on(hek) (HEK_FLAGS(hek) \|= HVhek_UTF8)
	356	#define HEK_UTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_UTF8)
	357	#define HEK_WASUTF8(hek) (HEK_FLAGS(hek) & HVhek_WASUTF8)
	358	#define HEK_WASUTF8_on(hek) (HEK_FLAGS(hek) \|= HVhek_WASUTF8)
	359	#define HEK_WASUTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
4b5190b5 NC	360	#define HEK_REHASH(hek) (HEK_FLAGS(hek) & HVhek_REHASH)
4b5190b5 NC	361	#define HEK_REHASH_on(hek) (HEK_FLAGS(hek) \|= HVhek_REHASH)
d18c6117	362
5cbe4eec	363	/* calculate HV array allocation */
36768cf4 NC	364	#ifndef PERL_USE_LARGE_HV_ALLOC
	365	/* Default to allocating the correct size - default to assuming that malloc()
	366	is not broken and is efficient at allocating blocks sized at powers-of-two.
	367	*/
d18c6117 GS	368	# define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
	369	#else
	370	# define MALLOC_OVERHEAD 16
	371	# define PERL_HV_ARRAY_ALLOC_BYTES(size) \
	372	(((size) < 64) \
	373	? (size) * sizeof(HE*) \
	374	: (size) * sizeof(HE) 2 - MALLOC_OVERHEAD)
	375	#endif
37d85e3a	376
e16e2ff8 NC	377	/* Flags for hv_iternext_flags. */
	378	#define HV_ITERNEXT_WANTPLACEHOLDERS 0x01 /* Don't skip placeholders. */
	379
7a7b9979	380	#define hv_iternext(hv) hv_iternext_flags(hv, 0)
bd61b366	381	#define hv_magic(hv, gv, how) sv_magic((SV)(hv), (SV)(gv), how, NULL, 0)
7a7b9979	382
37d85e3a JH	383	/* available as a function in hv.c */
	384	#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
	385	#define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)
bfcb3514	386
d1db91c6 NC	387	#define share_hek_hek(hek) \
	388	(++(((struct shared_he )(((char )hek) \
	389	- STRUCT_OFFSET(struct shared_he, \
	390	shared_he_hek))) \
de616631	391	->shared_he_he.he_valu.hent_refcount), \
d1db91c6 NC	392	hek)
d1db91c6 NC	393
bfcb3514 NC	394	/*
	395	* Local variables:
	396	* c-indentation-style: bsd
	397	* c-basic-offset: 4
	398	* indent-tabs-mode: t
	399	* End:
	400	*
	401	* ex: set ts=8 sts=4 sw=4 noet:
	402	*/