The EBCDIC gaps apply only to the real A-Z.

[perl5.git] / hv.h

diff --git a/hv.h b/hv.h
index 5def051..369bf3c 100644 (file)
--- a/hv.h
+++ b/hv.h
@@ -1,6 +1,6 @@
 /*    hv.h
  *
- *    Copyright (c) 1991-2001, Larry Wall
+ *    Copyright (c) 1991-2002, 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.
@@ -23,6 +23,8 @@ 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 telling whether the key is UTF8 */
 };
 
 /* hash structure: */
@@ -33,6 +35,7 @@ struct xpvhv {
     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 */
 
@@ -43,25 +46,39 @@ struct xpvhv {
 };
 
 /* 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) */
 #define PERL_HASH(hash,str,len) \
      STMT_START        { \
        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_PeRlHaSh>>5); \
+       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
 
 /*
+=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 a C<SV*> pointer where a C<char*> pointer
+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>.
 
@@ -111,19 +128,38 @@ C<SV*>.
 */
 
 /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
-#define HEf_SVKEY      -2      /* hent_key is a SV* */
+#define HEf_SVKEY      -2      /* hent_key is an SV* */
 
 
 #define Nullhv Null(HV*)
-#define HvARRAY(hv)    ((HE**)((XPVHV*)  SvANY(hv))->xhv_array)
+#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 HvKEYS(hv)     ((XPVHV*)  SvANY(hv))->xhv_keys
 #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)
@@ -177,7 +213,7 @@ C<SV*>.
 #define HEK_HASH(hek)          (hek)->hek_hash
 #define HEK_LEN(hek)           (hek)->hek_len
 #define HEK_KEY(hek)           (hek)->hek_key
-#define HEK_UTF8(hek)  (*(HEK_KEY(hek)+HEK_LEN(hek)))
+#define HEK_UTF8(hek)          (*(HEK_KEY(hek)+HEK_LEN(hek)+1))
 
 /* calculate HV array allocation */
 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
@@ -189,3 +225,7 @@ C<SV*>.
                         ? (size) * sizeof(HE*)                         \
                         : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
 #endif
+
+/* 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)