X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=hv.c;h=71009c9e20d44095bce676fff4ddbb9d88830890;hb=046ff0edbba626fc32c37c08cfba99cfeef41b6d;hp=27833f91d250de21d943c5fce16894d1a4be2a60;hpb=8e07c86ebc651fe92eb7e3b25f801f57cfb8dd6f;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/hv.c b/hv.c
index 27833f9..71009c9 100644
--- a/hv.c
+++ b/hv.c
@@ -17,6 +17,72 @@
 static void hsplit _((HV *hv));
 static void hfreeentries _((HV *hv));
 
+static HE* more_he();
+
+static HE*
+new_he()
+{
+    HE* he;
+    if (he_root) {
+        he = he_root;
+        he_root = HeNEXT(he);
+        return he;
+    }
+    return more_he();
+}
+
+static void
+del_he(p)
+HE* p;
+{
+    HeNEXT(p) = (HE*)he_root;
+    he_root = p;
+}
+
+static HE*
+more_he()
+{
+    register HE* he;
+    register HE* heend;
+    he_root = (HE*)safemalloc(1008);
+    he = he_root;
+    heend = &he[1008 / sizeof(HE) - 1];
+    while (he < heend) {
+        HeNEXT(he) = (HE*)(he + 1);
+        he++;
+    }
+    HeNEXT(he) = 0;
+    return new_he();
+}
+
+static HEK *
+save_hek(str, len, hash)
+char *str;
+I32 len;
+U32 hash;
+{
+    char *k;
+    register HEK *hek;
+    
+    New(54, k, HEK_BASESIZE + len + 1, char);
+    hek = (HEK*)k;
+    Copy(str, HEK_KEY(hek), len, char);
+    *(HEK_KEY(hek) + len) = '\0';
+    HEK_LEN(hek) = len;
+    HEK_HASH(hek) = hash;
+    return hek;
+}
+
+void
+unshare_hek(hek)
+HEK *hek;
+{
+    unsharepvn(HEK_KEY(hek),HEK_LEN(hek),HEK_HASH(hek));
+}
+
+/* (klen == HEf_SVKEY) is special for MAGICAL hv entries, meaning key slot
+ * contains an SV* */
+
 SV**
 hv_fetch(hv,key,klen,lval)
 HV *hv;
@@ -25,9 +91,7 @@ U32 klen;
 I32 lval;
 {
     register XPVHV* xhv;
-    register char *s;
-    register I32 i;
-    register I32 hash;
+    register U32 hash;
     register HE *entry;
     SV *sv;
 
@@ -55,21 +119,17 @@ I32 lval;
 	    return 0;
     }
 
-    i = klen;
-    hash = 0;
-    s = key;
-    while (i--)
-	hash = hash * 33 + *s++;
+    PERL_HASH(hash, key, klen);
 
     entry = ((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
-    for (; entry; entry = entry->hent_next) {
-	if (entry->hent_hash != hash)		/* strings can't be equal */
+    for (; entry; entry = HeNEXT(entry)) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
 	    continue;
-	if (entry->hent_klen != klen)
+	if (HeKLEN(entry) != klen)
 	    continue;
-	if (bcmp(entry->hent_key,key,klen))	/* is this it? */
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
 	    continue;
-	return &entry->hent_val;
+	return &HeVAL(entry);
     }
 #ifdef DYNAMIC_ENV_FETCH  /* %ENV lookup?  If so, try to fetch the value now */
     if (HvNAME(hv) && strEQ(HvNAME(hv),ENV_HV_NAME)) {
@@ -89,6 +149,86 @@ I32 lval;
     return 0;
 }
 
+/* returns a HE * structure with the all fields set */
+/* note that hent_val will be a mortal sv for MAGICAL hashes */
+HE *
+hv_fetch_ent(hv,keysv,lval,hash)
+HV *hv;
+SV *keysv;
+I32 lval;
+register U32 hash;
+{
+    register XPVHV* xhv;
+    register char *key;
+    STRLEN klen;
+    register HE *entry;
+    SV *sv;
+
+    if (!hv)
+	return 0;
+
+    if (SvRMAGICAL(hv) && mg_find((SV*)hv,'P')) {
+	static HE mh;
+
+	sv = sv_newmortal();
+	keysv = sv_2mortal(newSVsv(keysv));
+	mg_copy((SV*)hv, sv, (char*)keysv, HEf_SVKEY);
+	if (!HeKEY_hek(&mh)) {
+	    char *k;
+	    New(54, k, HEK_BASESIZE + sizeof(SV*), char);
+	    HeKEY_hek(&mh) = (HEK*)k;
+	    HeKLEN(&mh) = HEf_SVKEY;	/* key will always hold an SV* */
+	}
+	HeSVKEY_set(&mh, keysv);
+	HeVAL(&mh) = sv;
+	return &mh;
+    }
+
+    xhv = (XPVHV*)SvANY(hv);
+    if (!xhv->xhv_array) {
+	if (lval 
+#ifdef DYNAMIC_ENV_FETCH  /* if it's an %ENV lookup, we may get it on the fly */
+	         || (HvNAME(hv) && strEQ(HvNAME(hv),ENV_HV_NAME))
+#endif
+	                                                          )
+	    Newz(503,xhv->xhv_array, sizeof(HE*) * (xhv->xhv_max + 1), char);
+	else
+	    return 0;
+    }
+
+    key = SvPV(keysv, klen);
+    
+    if (!hash)
+	PERL_HASH(hash, key, klen);
+
+    entry = ((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
+    for (; entry; entry = HeNEXT(entry)) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
+	    continue;
+	if (HeKLEN(entry) != klen)
+	    continue;
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
+	    continue;
+	return entry;
+    }
+#ifdef DYNAMIC_ENV_FETCH  /* %ENV lookup?  If so, try to fetch the value now */
+    if (HvNAME(hv) && strEQ(HvNAME(hv),ENV_HV_NAME)) {
+      char *gotenv;
+
+      gotenv = my_getenv(key);
+      if (gotenv != NULL) {
+        sv = newSVpv(gotenv,strlen(gotenv));
+        return hv_store_ent(hv,keysv,sv,hash);
+      }
+    }
+#endif
+    if (lval) {		/* gonna assign to this, so it better be there */
+	sv = NEWSV(61,0);
+	return hv_store_ent(hv,keysv,sv,hash);
+    }
+    return 0;
+}
+
 SV**
 hv_store(hv,key,klen,val,hash)
 HV *hv;
@@ -98,7 +238,6 @@ SV *val;
 register U32 hash;
 {
     register XPVHV* xhv;
-    register char *s;
     register I32 i;
     register HE *entry;
     register HE **oentry;
@@ -109,46 +248,116 @@ register U32 hash;
     xhv = (XPVHV*)SvANY(hv);
     if (SvMAGICAL(hv)) {
 	mg_copy((SV*)hv, val, key, klen);
-#ifndef OVERLOAD
-	if (!xhv->xhv_array)
-	    return 0;
-#else
-	if (!xhv->xhv_array && (SvMAGIC(hv)->mg_type != 'A'
-				|| SvMAGIC(hv)->mg_moremagic))
-	  return 0;
+	if (!xhv->xhv_array
+	    && (SvMAGIC(hv)->mg_moremagic
+		|| (SvMAGIC(hv)->mg_type != 'E'
+#ifdef OVERLOAD
+		    && SvMAGIC(hv)->mg_type != 'A'
 #endif /* OVERLOAD */
+		    )))
+	    return 0;
     }
-    if (!hash) {
-    i = klen;
-    s = key;
-    while (i--)
-	hash = hash * 33 + *s++;
+    if (!hash)
+	PERL_HASH(hash, key, klen);
+
+    if (!xhv->xhv_array)
+	Newz(505, xhv->xhv_array, sizeof(HE**) * (xhv->xhv_max + 1), char);
+
+    oentry = &((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
+    i = 1;
+
+    for (entry = *oentry; entry; i=0, entry = HeNEXT(entry)) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
+	    continue;
+	if (HeKLEN(entry) != klen)
+	    continue;
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
+	    continue;
+	SvREFCNT_dec(HeVAL(entry));
+	HeVAL(entry) = val;
+	return &HeVAL(entry);
+    }
+
+    entry = new_he();
+    if (HvSHAREKEYS(hv))
+	HeKEY_hek(entry) = share_hek(key, klen, hash);
+    else                                       /* gotta do the real thing */
+	HeKEY_hek(entry) = save_hek(key, klen, hash);
+    HeVAL(entry) = val;
+    HeNEXT(entry) = *oentry;
+    *oentry = entry;
+
+    xhv->xhv_keys++;
+    if (i) {				/* initial entry? */
+	++xhv->xhv_fill;
+	if (xhv->xhv_keys > xhv->xhv_max)
+	    hsplit(hv);
+    }
+
+    return &HeVAL(entry);
+}
+
+HE *
+hv_store_ent(hv,keysv,val,hash)
+HV *hv;
+SV *keysv;
+SV *val;
+register U32 hash;
+{
+    register XPVHV* xhv;
+    register char *key;
+    STRLEN klen;
+    register I32 i;
+    register HE *entry;
+    register HE **oentry;
+
+    if (!hv)
+	return 0;
+
+    xhv = (XPVHV*)SvANY(hv);
+    if (SvMAGICAL(hv)) {
+	keysv = sv_2mortal(newSVsv(keysv));
+	mg_copy((SV*)hv, val, (char*)keysv, HEf_SVKEY);
+	if (!xhv->xhv_array
+	    && (SvMAGIC(hv)->mg_moremagic
+		|| (SvMAGIC(hv)->mg_type != 'E'
+#ifdef OVERLOAD
+		    && SvMAGIC(hv)->mg_type != 'A'
+#endif /* OVERLOAD */
+		    )))
+	  return Nullhe;
     }
 
+    key = SvPV(keysv, klen);
+    
+    if (!hash)
+	PERL_HASH(hash, key, klen);
+
     if (!xhv->xhv_array)
 	Newz(505, xhv->xhv_array, sizeof(HE**) * (xhv->xhv_max + 1), char);
 
     oentry = &((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
     i = 1;
 
-    for (entry = *oentry; entry; i=0, entry = entry->hent_next) {
-	if (entry->hent_hash != hash)		/* strings can't be equal */
+    for (entry = *oentry; entry; i=0, entry = HeNEXT(entry)) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
 	    continue;
-	if (entry->hent_klen != klen)
+	if (HeKLEN(entry) != klen)
 	    continue;
-	if (bcmp(entry->hent_key,key,klen))	/* is this it? */
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
 	    continue;
-	SvREFCNT_dec(entry->hent_val);
-	entry->hent_val = val;
-	return &entry->hent_val;
+	SvREFCNT_dec(HeVAL(entry));
+	HeVAL(entry) = val;
+	return entry;
     }
-    New(501,entry, 1, HE);
 
-    entry->hent_klen = klen;
-    entry->hent_key = savepvn(key,klen);
-    entry->hent_val = val;
-    entry->hent_hash = hash;
-    entry->hent_next = *oentry;
+    entry = new_he();
+    if (HvSHAREKEYS(hv))
+	HeKEY_hek(entry) = share_hek(key, klen, hash);
+    else                                       /* gotta do the real thing */
+	HeKEY_hek(entry) = save_hek(key, klen, hash);
+    HeVAL(entry) = val;
+    HeNEXT(entry) = *oentry;
     *oentry = entry;
 
     xhv->xhv_keys++;
@@ -158,7 +367,7 @@ register U32 hash;
 	    hsplit(hv);
     }
 
-    return &entry->hent_val;
+    return entry;
 }
 
 SV *
@@ -169,9 +378,8 @@ U32 klen;
 I32 flags;
 {
     register XPVHV* xhv;
-    register char *s;
     register I32 i;
-    register I32 hash;
+    register U32 hash;
     register HE *entry;
     register HE **oentry;
     SV *sv;
@@ -181,6 +389,68 @@ I32 flags;
     if (SvRMAGICAL(hv)) {
 	sv = *hv_fetch(hv, key, klen, TRUE);
 	mg_clear(sv);
+	if (mg_find(sv, 's')) {
+	    return Nullsv;		/* %SIG elements cannot be deleted */
+	}
+	if (mg_find(sv, 'p')) {
+	    sv_unmagic(sv, 'p');	/* No longer an element */
+	    return sv;
+	}
+    }
+    xhv = (XPVHV*)SvANY(hv);
+    if (!xhv->xhv_array)
+	return Nullsv;
+
+    PERL_HASH(hash, key, klen);
+
+    oentry = &((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
+    entry = *oentry;
+    i = 1;
+    for (; entry; i=0, oentry = &HeNEXT(entry), entry = *oentry) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
+	    continue;
+	if (HeKLEN(entry) != klen)
+	    continue;
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
+	    continue;
+	*oentry = HeNEXT(entry);
+	if (i && !*oentry)
+	    xhv->xhv_fill--;
+	if (flags & G_DISCARD)
+	    sv = Nullsv;
+	else
+	    sv = sv_mortalcopy(HeVAL(entry));
+	if (entry == xhv->xhv_eiter)
+	    HvLAZYDEL_on(hv);
+	else
+	    he_free(hv, entry);
+	--xhv->xhv_keys;
+	return sv;
+    }
+    return Nullsv;
+}
+
+SV *
+hv_delete_ent(hv,keysv,flags,hash)
+HV *hv;
+SV *keysv;
+I32 flags;
+U32 hash;
+{
+    register XPVHV* xhv;
+    register I32 i;
+    register char *key;
+    STRLEN klen;
+    register HE *entry;
+    register HE **oentry;
+    SV *sv;
+    
+    if (!hv)
+	return Nullsv;
+    if (SvRMAGICAL(hv)) {
+	entry = hv_fetch_ent(hv, keysv, TRUE, hash);
+	sv = HeVAL(entry);
+	mg_clear(sv);
 	if (mg_find(sv, 'p')) {
 	    sv_unmagic(sv, 'p');	/* No longer an element */
 	    return sv;
@@ -189,33 +459,33 @@ I32 flags;
     xhv = (XPVHV*)SvANY(hv);
     if (!xhv->xhv_array)
 	return Nullsv;
-    i = klen;
-    hash = 0;
-    s = key;
-    while (i--)
-	hash = hash * 33 + *s++;
+
+    key = SvPV(keysv, klen);
+    
+    if (!hash)
+	PERL_HASH(hash, key, klen);
 
     oentry = &((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
     entry = *oentry;
     i = 1;
-    for (; entry; i=0, oentry = &entry->hent_next, entry = *oentry) {
-	if (entry->hent_hash != hash)		/* strings can't be equal */
+    for (; entry; i=0, oentry = &HeNEXT(entry), entry = *oentry) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
 	    continue;
-	if (entry->hent_klen != klen)
+	if (HeKLEN(entry) != klen)
 	    continue;
-	if (bcmp(entry->hent_key,key,klen))	/* is this it? */
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
 	    continue;
-	*oentry = entry->hent_next;
+	*oentry = HeNEXT(entry);
 	if (i && !*oentry)
 	    xhv->xhv_fill--;
 	if (flags & G_DISCARD)
 	    sv = Nullsv;
 	else
-	    sv = sv_mortalcopy(entry->hent_val);
+	    sv = sv_mortalcopy(HeVAL(entry));
 	if (entry == xhv->xhv_eiter)
-	    entry->hent_klen = -1;
+	    HvLAZYDEL_on(hv);
 	else
-	    he_free(entry);
+	    he_free(hv, entry);
 	--xhv->xhv_keys;
 	return sv;
     }
@@ -229,9 +499,7 @@ char *key;
 U32 klen;
 {
     register XPVHV* xhv;
-    register char *s;
-    register I32 i;
-    register I32 hash;
+    register U32 hash;
     register HE *entry;
     SV *sv;
 
@@ -251,19 +519,62 @@ U32 klen;
     if (!xhv->xhv_array)
 	return 0; 
 
-    i = klen;
-    hash = 0;
-    s = key;
-    while (i--)
-	hash = hash * 33 + *s++;
+    PERL_HASH(hash, key, klen);
+
+    entry = ((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
+    for (; entry; entry = HeNEXT(entry)) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
+	    continue;
+	if (HeKLEN(entry) != klen)
+	    continue;
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
+	    continue;
+	return TRUE;
+    }
+    return FALSE;
+}
+
+
+bool
+hv_exists_ent(hv,keysv,hash)
+HV *hv;
+SV *keysv;
+U32 hash;
+{
+    register XPVHV* xhv;
+    register char *key;
+    STRLEN klen;
+    register HE *entry;
+    SV *sv;
+
+    if (!hv)
+	return 0;
+
+    if (SvRMAGICAL(hv)) {
+	if (mg_find((SV*)hv,'P')) {
+	    sv = sv_newmortal();
+	    keysv = sv_2mortal(newSVsv(keysv));
+	    mg_copy((SV*)hv, sv, (char*)keysv, HEf_SVKEY); 
+	    magic_existspack(sv, mg_find(sv, 'p'));
+	    return SvTRUE(sv);
+	}
+    }
+
+    xhv = (XPVHV*)SvANY(hv);
+    if (!xhv->xhv_array)
+	return 0; 
+
+    key = SvPV(keysv, klen);
+    if (!hash)
+	PERL_HASH(hash, key, klen);
 
     entry = ((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
-    for (; entry; entry = entry->hent_next) {
-	if (entry->hent_hash != hash)		/* strings can't be equal */
+    for (; entry; entry = HeNEXT(entry)) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
 	    continue;
-	if (entry->hent_klen != klen)
+	if (HeKLEN(entry) != klen)
 	    continue;
-	if (bcmp(entry->hent_key,key,klen))	/* is this it? */
+	if (memNE(HeKEY(entry),key,klen))	/* is this it? */
 	    continue;
 	return TRUE;
     }
@@ -282,10 +593,33 @@ HV *hv;
     register HE **b;
     register HE *entry;
     register HE **oentry;
+#ifndef STRANGE_MALLOC
+    I32 tmp;
+#endif
 
     a = (HE**)xhv->xhv_array;
     nomemok = TRUE;
+#ifdef STRANGE_MALLOC
     Renew(a, newsize, HE*);
+#else
+    i = newsize * sizeof(HE*);
+#define MALLOC_OVERHEAD 16
+    tmp = MALLOC_OVERHEAD;
+    while (tmp - MALLOC_OVERHEAD < i)
+	tmp += tmp;
+    tmp -= MALLOC_OVERHEAD;
+    tmp /= sizeof(HE*);
+    assert(tmp >= newsize);
+    New(2,a, tmp, HE*);
+    Copy(xhv->xhv_array, a, oldsize, HE*);
+    if (oldsize >= 64 && !nice_chunk) {
+	nice_chunk = (char*)xhv->xhv_array;
+	nice_chunk_size = oldsize * sizeof(HE*) * 2 - MALLOC_OVERHEAD;
+    }
+    else
+	Safefree(xhv->xhv_array);
+#endif
+
     nomemok = FALSE;
     Zero(&a[oldsize], oldsize, HE*);		/* zero 2nd half*/
     xhv->xhv_max = --newsize;
@@ -296,16 +630,94 @@ HV *hv;
 	    continue;
 	b = a+oldsize;
 	for (oentry = a, entry = *a; entry; entry = *oentry) {
-	    if ((entry->hent_hash & newsize) != i) {
-		*oentry = entry->hent_next;
-		entry->hent_next = *b;
+	    if ((HeHASH(entry) & newsize) != i) {
+		*oentry = HeNEXT(entry);
+		HeNEXT(entry) = *b;
 		if (!*b)
 		    xhv->xhv_fill++;
 		*b = entry;
 		continue;
 	    }
 	    else
-		oentry = &entry->hent_next;
+		oentry = &HeNEXT(entry);
+	}
+	if (!*a)				/* everything moved */
+	    xhv->xhv_fill--;
+    }
+}
+
+void
+hv_ksplit(hv, newmax)
+HV *hv;
+IV newmax;
+{
+    register XPVHV* xhv = (XPVHV*)SvANY(hv);
+    I32 oldsize = (I32) xhv->xhv_max + 1; /* sic(k) */
+    register I32 newsize;
+    register I32 i;
+    register I32 j;
+    register HE **a;
+    register HE *entry;
+    register HE **oentry;
+
+    newsize = (I32) newmax;			/* possible truncation here */
+    if (newsize != newmax || newmax <= oldsize)
+	return;
+    while ((newsize & (1 + ~newsize)) != newsize) {
+	newsize &= ~(newsize & (1 + ~newsize));	/* get proper power of 2 */
+    }
+    if (newsize < newmax)
+	newsize *= 2;
+    if (newsize < newmax)
+	return;					/* overflow detection */
+
+    a = (HE**)xhv->xhv_array;
+    if (a) {
+	nomemok = TRUE;
+#ifdef STRANGE_MALLOC
+	Renew(a, newsize, HE*);
+#else
+	i = newsize * sizeof(HE*);
+	j = MALLOC_OVERHEAD;
+	while (j - MALLOC_OVERHEAD < i)
+	    j += j;
+	j -= MALLOC_OVERHEAD;
+	j /= sizeof(HE*);
+	assert(j >= newsize);
+	New(2, a, j, HE*);
+	Copy(xhv->xhv_array, a, oldsize, HE*);
+	if (oldsize >= 64 && !nice_chunk) {
+	    nice_chunk = (char*)xhv->xhv_array;
+	    nice_chunk_size = oldsize * sizeof(HE*) * 2 - MALLOC_OVERHEAD;
+	}
+	else
+	    Safefree(xhv->xhv_array);
+#endif
+	nomemok = FALSE;
+	Zero(&a[oldsize], newsize-oldsize, HE*); /* zero 2nd half*/
+    }
+    else {
+	Newz(0, a, newsize, HE*);
+    }
+    xhv->xhv_max = --newsize;
+    xhv->xhv_array = (char*)a;
+    if (!xhv->xhv_fill)				/* skip rest if no entries */
+	return;
+
+    for (i=0; i<oldsize; i++,a++) {
+	if (!*a)				/* non-existent */
+	    continue;
+	for (oentry = a, entry = *a; entry; entry = *oentry) {
+	    if ((j = (HeHASH(entry) & newsize)) != i) {
+		j -= i;
+		*oentry = HeNEXT(entry);
+		if (!(HeNEXT(entry) = a[j]))
+		    xhv->xhv_fill++;
+		a[j] = entry;
+		continue;
+	    }
+	    else
+		oentry = &HeNEXT(entry);
 	}
 	if (!*a)				/* everything moved */
 	    xhv->xhv_fill--;
@@ -323,6 +735,9 @@ newHV()
     xhv = (XPVHV*)SvANY(hv);
     SvPOK_off(hv);
     SvNOK_off(hv);
+#ifndef NODEFAULT_SHAREKEYS    
+    HvSHAREKEYS_on(hv);         /* key-sharing on by default */
+#endif    
     xhv->xhv_max = 7;		/* start with 8 buckets */
     xhv->xhv_fill = 0;
     xhv->xhv_pmroot = 0;
@@ -331,25 +746,45 @@ newHV()
 }
 
 void
-he_free(hent)
+he_free(hv, hent)
+HV *hv;
 register HE *hent;
 {
     if (!hent)
 	return;
-    SvREFCNT_dec(hent->hent_val);
-    Safefree(hent->hent_key);
-    Safefree(hent);
+    if (isGV(HeVAL(hent)) && GvCVu(HeVAL(hent)) && HvNAME(hv))
+	sub_generation++;	/* may be deletion of method from stash */
+    SvREFCNT_dec(HeVAL(hent));
+    if (HeKLEN(hent) == HEf_SVKEY) {
+	SvREFCNT_dec(HeKEY_sv(hent));
+        Safefree(HeKEY_hek(hent));
+    }
+    else if (HvSHAREKEYS(hv))
+	unshare_hek(HeKEY_hek(hent));
+    else
+	Safefree(HeKEY_hek(hent));
+    del_he(hent);
 }
 
 void
-he_delayfree(hent)
+he_delayfree(hv, hent)
+HV *hv;
 register HE *hent;
 {
     if (!hent)
 	return;
-    sv_2mortal(hent->hent_val);	/* free between statements */
-    Safefree(hent->hent_key);
-    Safefree(hent);
+    if (isGV(HeVAL(hent)) && GvCVu(HeVAL(hent)) && HvNAME(hv))
+	sub_generation++;	/* may be deletion of method from stash */
+    sv_2mortal(HeVAL(hent));	/* free between statements */
+    if (HeKLEN(hent) == HEf_SVKEY) {
+	sv_2mortal(HeKEY_sv(hent));
+	Safefree(HeKEY_hek(hent));
+    }
+    else if (HvSHAREKEYS(hv))
+	unshare_hek(HeKEY_hek(hent));
+    else
+	Safefree(HeKEY_hek(hent));
+    del_he(hent);
 }
 
 void
@@ -392,8 +827,8 @@ HV *hv;
     for (;;) {
 	if (hent) {
 	    ohent = hent;
-	    hent = hent->hent_next;
-	    he_free(ohent);
+	    hent = HeNEXT(hent);
+	    he_free(hv, ohent);
 	}
 	if (!hent) {
 	    if (++riter > max)
@@ -433,8 +868,13 @@ HV *hv;
 {
     register XPVHV* xhv = (XPVHV*)SvANY(hv);
     HE *entry = xhv->xhv_eiter;
-    if (entry && entry->hent_klen < 0)	/* was deleted earlier? */
-	he_free(entry);
+#ifdef DYNAMIC_ENV_FETCH  /* set up %ENV for iteration */
+    if (HvNAME(hv) && strEQ(HvNAME(hv),ENV_HV_NAME)) prime_env_iter();
+#endif
+    if (entry && HvLAZYDEL(hv)) {	/* was deleted earlier? */
+	HvLAZYDEL_off(hv);
+	he_free(hv, entry);
+    }
     xhv->xhv_riter = -1;
     xhv->xhv_eiter = Null(HE*);
     return xhv->xhv_fill;
@@ -457,47 +897,51 @@ HV *hv;
     if (SvRMAGICAL(hv) && (mg = mg_find((SV*)hv,'P'))) {
 	SV *key = sv_newmortal();
 	if (entry) {
-	    sv_usepvn(key, entry->hent_key, entry->hent_klen);
-	    entry->hent_key = 0;
+	    sv_setsv(key, HeSVKEY_force(entry));
+	    SvREFCNT_dec(HeSVKEY(entry));	/* get rid of previous key */
 	}
 	else {
-	    Newz(504,entry, 1, HE);
-	    xhv->xhv_eiter = entry;
+	    char *k;
+	    HEK *hek;
+
+	    xhv->xhv_eiter = entry = new_he();  /* one HE per MAGICAL hash */
+	    Zero(entry, 1, HE);
+	    Newz(54, k, HEK_BASESIZE + sizeof(SV*), char);
+	    hek = (HEK*)k;
+	    HeKEY_hek(entry) = hek;
+	    HeKLEN(entry) = HEf_SVKEY;
 	}
 	magic_nextpack((SV*) hv,mg,key);
         if (SvOK(key)) {
-	    STRLEN len;
-	    entry->hent_key = SvPV_force(key, len);
-	    entry->hent_klen = len;
-	    SvPOK_off(key);
-	    SvPVX(key) = 0;
-	    return entry;
+	    /* force key to stay around until next time */
+	    HeSVKEY_set(entry, SvREFCNT_inc(key));
+	    return entry;		/* beware, hent_val is not set */
         }
-	if (entry->hent_val)
-	    SvREFCNT_dec(entry->hent_val);
-	Safefree(entry);
+	if (HeVAL(entry))
+	    SvREFCNT_dec(HeVAL(entry));
+	Safefree(HeKEY_hek(entry));
+	del_he(entry);
 	xhv->xhv_eiter = Null(HE*);
 	return Null(HE*);
     }
 
     if (!xhv->xhv_array)
-	entry = Null(HE*);
-    else
-    do {
-	if (entry)
-	    entry = entry->hent_next;
-	if (!entry) {
-	    ++xhv->xhv_riter;
-	    if (xhv->xhv_riter > xhv->xhv_max) {
-		xhv->xhv_riter = -1;
-		break;
-	    }
-	    entry = ((HE**)xhv->xhv_array)[xhv->xhv_riter];
+	Newz(506,xhv->xhv_array, sizeof(HE*) * (xhv->xhv_max + 1), char);
+    if (entry)
+	entry = HeNEXT(entry);
+    while (!entry) {
+	++xhv->xhv_riter;
+	if (xhv->xhv_riter > xhv->xhv_max) {
+	    xhv->xhv_riter = -1;
+	    break;
 	}
-    } while (!entry);
+	entry = ((HE**)xhv->xhv_array)[xhv->xhv_riter];
+    }
 
-    if (oldentry && oldentry->hent_klen < 0)	/* was deleted earlier? */
-	he_free(oldentry);
+    if (oldentry && HvLAZYDEL(hv)) {		/* was deleted earlier? */
+	HvLAZYDEL_off(hv);
+	he_free(hv, oldentry);
+    }
 
     xhv->xhv_eiter = entry;
     return entry;
@@ -508,8 +952,25 @@ hv_iterkey(entry,retlen)
 register HE *entry;
 I32 *retlen;
 {
-    *retlen = entry->hent_klen;
-    return entry->hent_key;
+    if (HeKLEN(entry) == HEf_SVKEY) {
+	return SvPV(HeKEY_sv(entry), *(STRLEN*)retlen);
+    }
+    else {
+	*retlen = HeKLEN(entry);
+	return HeKEY(entry);
+    }
+}
+
+/* unlike hv_iterval(), this always returns a mortal copy of the key */
+SV *
+hv_iterkeysv(entry)
+register HE *entry;
+{
+    if (HeKLEN(entry) == HEf_SVKEY)
+	return sv_mortalcopy(HeKEY_sv(entry));
+    else
+	return sv_2mortal(newSVpv((HeKLEN(entry) ? HeKEY(entry) : ""),
+				  HeKLEN(entry)));
 }
 
 SV *
@@ -520,11 +981,13 @@ register HE *entry;
     if (SvRMAGICAL(hv)) {
 	if (mg_find((SV*)hv,'P')) {
 	    SV* sv = sv_newmortal();
-	    mg_copy((SV*)hv, sv, entry->hent_key, entry->hent_klen);
+	    if (HeKLEN(entry) == HEf_SVKEY)
+		mg_copy((SV*)hv, sv, (char*)HeKEY_sv(entry), HEf_SVKEY);
+	    else mg_copy((SV*)hv, sv, HeKEY(entry), HeKLEN(entry));
 	    return sv;
 	}
     }
-    return entry->hent_val;
+    return HeVAL(entry);
 }
 
 SV *
@@ -548,3 +1011,112 @@ int how;
 {
     sv_magic((SV*)hv, (SV*)gv, how, Nullch, 0);
 }
+
+char*	
+sharepvn(sv, len, hash)
+char* sv;
+I32 len;
+U32 hash;
+{
+    return HEK_KEY(share_hek(sv, len, hash));
+}
+
+/* possibly free a shared string if no one has access to it
+ * len and hash must both be valid for str.
+ */
+void
+unsharepvn(str, len, hash)
+char* str;
+I32 len;
+U32 hash;
+{
+    register XPVHV* xhv;
+    register HE *entry;
+    register HE **oentry;
+    register I32 i = 1;
+    I32 found = 0;
+    
+    /* what follows is the moral equivalent of:
+    if ((Svp = hv_fetch(strtab, tmpsv, FALSE, hash))) {
+	if (--*Svp == Nullsv)
+	    hv_delete(strtab, str, len, G_DISCARD, hash);
+    } */
+    xhv = (XPVHV*)SvANY(strtab);
+    /* assert(xhv_array != 0) */
+    oentry = &((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
+    for (entry = *oentry; entry; i=0, oentry = &HeNEXT(entry), entry = *oentry) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
+	    continue;
+	if (HeKLEN(entry) != len)
+	    continue;
+	if (memNE(HeKEY(entry),str,len))	/* is this it? */
+	    continue;
+	found = 1;
+	if (--HeVAL(entry) == Nullsv) {
+	    *oentry = HeNEXT(entry);
+	    if (i && !*oentry)
+		xhv->xhv_fill--;
+	    Safefree(HeKEY_hek(entry));
+	    del_he(entry);
+	    --xhv->xhv_keys;
+	}
+	break;
+    }
+    
+    if (!found)
+	warn("Attempt to free non-existent shared string");    
+}
+
+/* get a (constant) string ptr from the global string table
+ * string will get added if it is not already there.
+ * len and hash must both be valid for str.
+ */
+HEK *
+share_hek(str, len, hash)
+char *str;
+I32 len;
+register U32 hash;
+{
+    register XPVHV* xhv;
+    register HE *entry;
+    register HE **oentry;
+    register I32 i = 1;
+    I32 found = 0;
+
+    /* what follows is the moral equivalent of:
+       
+    if (!(Svp = hv_fetch(strtab, str, len, FALSE)))
+    	hv_store(strtab, str, len, Nullsv, hash);
+    */
+    xhv = (XPVHV*)SvANY(strtab);
+    /* assert(xhv_array != 0) */
+    oentry = &((HE**)xhv->xhv_array)[hash & (I32) xhv->xhv_max];
+    for (entry = *oentry; entry; i=0, entry = HeNEXT(entry)) {
+	if (HeHASH(entry) != hash)		/* strings can't be equal */
+	    continue;
+	if (HeKLEN(entry) != len)
+	    continue;
+	if (memNE(HeKEY(entry),str,len))	/* is this it? */
+	    continue;
+	found = 1;
+	break;
+    }
+    if (!found) {
+	entry = new_he();
+	HeKEY_hek(entry) = save_hek(str, len, hash);
+	HeVAL(entry) = Nullsv;
+	HeNEXT(entry) = *oentry;
+	*oentry = entry;
+	xhv->xhv_keys++;
+	if (i) {				/* initial entry? */
+	    ++xhv->xhv_fill;
+	    if (xhv->xhv_keys > xhv->xhv_max)
+		hsplit(strtab);
+	}
+    }
+
+    ++HeVAL(entry);				/* use value slot as REFCNT */
+    return HeKEY_hek(entry);
+}
+
+