X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=hv.h;h=08f3bed7d5b63c79e076a74b77b84840b068e024;hb=1724fb8e7df982f0fd79fb192e0146e474675132;hp=11a602c1b75e8efb12e06c686d6d0b10307e42e5;hpb=d18c61170a30691556a1da7413e13241a92f4e0a;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/hv.h b/hv.h
index 11a602c..08f3bed 100644
--- a/hv.h
+++ b/hv.h
@@ -1,27 +1,31 @@
 /*    hv.h
  *
- *    Copyright (c) 1991-1999, 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 */
@@ -38,6 +42,7 @@ struct xpvhv {
     char	*xhv_name;	/* name, if a symbol table */
 };
 
+/* hash a key */
 #define PERL_HASH(hash,str,len) \
      STMT_START	{ \
 	register const char *s_PeRlHaSh = str; \
@@ -48,6 +53,62 @@ struct xpvhv {
 	(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* */
@@ -115,6 +176,7 @@ struct xpvhv {
 #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