X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/c4f23d77f4b3486a36335c4460cbfd4e81e37892..9faf8d75b36b5058433b7bc0eebfb6e8674b88c7:/hv.h

diff --git a/hv.h b/hv.h
index 91b6fec..08f3bed 100644
--- a/hv.h
+++ b/hv.h
@@ -1,34 +1,38 @@
 /*    hv.h
  *
- *    Copyright (c) 1991-1997, Larry Wall
+ *    Copyright (c) 1991-2000, 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.
  *
  */
 
+/* typedefs to eliminate some typing */
 typedef struct he HE;
 typedef struct hek HEK;
 
+/* entry in hash value chain */
 struct he {
-    HE		*hent_next;
-    HEK		*hent_hek;
-    SV		*hent_val;
+    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;
-    I32		hek_len;
-    char	hek_key[1];
+    U32		hek_hash;	/* hash of key */
+    I32		hek_len;	/* length of hash key */
+    char	hek_key[1];	/* variable-length hash key */
 };
 
+/* 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 */
-    double	xnv_nv;		/* numeric value, if any */
+    NV		xnv_nv;		/* numeric value, if any */
     MAGIC*	xmg_magic;	/* magic for scalar array */
     HV*		xmg_stash;	/* class package */
 
@@ -38,16 +42,73 @@ struct xpvhv {
     char	*xhv_name;	/* name, if a symbol table */
 };
 
+/* hash a key */
 #define PERL_HASH(hash,str,len) \
      STMT_START	{ \
-	register char *s_PeRlHaSh = str; \
+	register const char *s_PeRlHaSh = str; \
 	register I32 i_PeRlHaSh = len; \
 	register U32 hash_PeRlHaSh = 0; \
 	while (i_PeRlHaSh--) \
 	    hash_PeRlHaSh = hash_PeRlHaSh * 33 + *s_PeRlHaSh++; \
-	(hash) = hash_PeRlHaSh; \
+	(hash) = hash_PeRlHaSh + (hash_PeRlHaSh>>5); \
     } STMT_END
 
+/*
+=for apidoc AmU||HEf_SVKEY
+This flag, used in the length slot of hash entries and magic structures,
+specifies the structure contains a C<SV*> pointer where a C<char*> pointer
+is to be expected. (For information only--not to be used).
+
+=for apidoc AmU||Nullhv
+Null HV pointer.
+
+=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 a SV* */
@@ -71,8 +132,6 @@ struct xpvhv {
 #define HvLAZYDEL_on(hv)	(SvFLAGS(hv) |= SVphv_LAZYDEL)
 #define HvLAZYDEL_off(hv)	(SvFLAGS(hv) &= ~SVphv_LAZYDEL)
 
-#ifdef OVERLOAD
-
 /* Maybe amagical: */
 /* #define HV_AMAGICmb(hv)      (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */
 
@@ -86,8 +145,6 @@ struct xpvhv {
 #define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
 */
 
-#endif /* OVERLOAD */
-
 #define Nullhe Null(HE*)
 #define HeNEXT(he)		(he)->hent_next
 #define HeKEY_hek(he)		(he)->hent_hek
@@ -108,9 +165,9 @@ struct xpvhv {
 #define HeSVKEY_force(he)	(HeKEY(he) ?				\
 				 ((HeKLEN(he) == HEf_SVKEY) ?		\
 				  HeKEY_sv(he) :			\
-				  sv_2mortal(newSVpv(HeKEY(he),		\
+				  sv_2mortal(newSVpvn(HeKEY(he),	\
 						     HeKLEN(he)))) :	\
-				 &sv_undef)
+				 &PL_sv_undef)
 #define HeSVKEY_set(he,sv)	((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
 
 #define Nullhek Null(HEK*)
@@ -118,3 +175,14 @@ struct xpvhv {
 #define HEK_HASH(hek)		(hek)->hek_hash
 #define HEK_LEN(hek)		(hek)->hek_len
 #define HEK_KEY(hek)		(hek)->hek_key
+
+/* 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