-/* $RCSfile: array.h,v $$Revision: 4.1 $$Date: 92/08/07 17:18:24 $
+/* av.h
*
- * Copyright (c) 1991, Larry Wall
+ * Copyright (C) 1991, 1992, 1993, 1995, 1996, 1997, 1998, 1999, 2000,
+ * 2001, 2002, 2005, 2006, 2007, 2008, 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.
*
- * $Log: array.h,v $
- * Revision 4.1 92/08/07 17:18:24 lwall
- * Stage 6 Snapshot
- *
- * Revision 4.0.1.2 92/06/08 11:45:57 lwall
- * patch20: removed implicit int declarations on funcions
- *
- * Revision 4.0.1.1 91/06/07 10:19:20 lwall
- * patch4: new copyright notice
- *
- * Revision 4.0 91/03/20 01:03:44 lwall
- * 4.0 baseline.
- *
*/
struct xpvav {
- char * xpv_pv; /* pointer to malloced string */
- STRLEN xpv_cur; /* length of xp_pv as a C string */
- STRLEN xpv_len; /* allocated size */
- STRLEN xof_off; /* ptr is incremented by offset */
- double xnv_nv; /* numeric value, if any */
- MAGIC* xmg_magic; /* magic for scalar array */
HV* xmg_stash; /* class package */
+ union _xmgu xmg_u;
+ SSize_t xav_fill; /* Index of last element present */
+ SSize_t xav_max; /* max index for which array has space */
+ SV** xav_alloc; /* pointer to beginning of C array of SVs */
+};
- MAGIC* xav_magic; /* magic for elements */
+/* SV* xav_arylen; */
- SV** xav_array;
- SV** xav_alloc;
- SV* xav_arylen;
- I32 xav_max;
- I32 xav_fill;
- U8 xav_flags;
-};
+/* SVpav_REAL is set for all AVs whose xav_array contents are refcounted
+ * and initialized such that any element can be retrieved as a SV*.
+ * Such AVs may be referred to as "real" AVs. Examples include regular
+ * perl arrays, tiedarrays (since v5.16), and padlist AVs.
+ *
+ * Some things do not set SVpav_REAL, to indicate that they are cheating
+ * (for efficiency) by not refcounting the AV's contents or ensuring that
+ * all elements are safe for arbitrary access. This type of AV may be
+ * referred to as "fake" AVs. Examples include "@_" (unless tied), the
+ * scratchpad list, and the backrefs list on an object or stash.
+ *
+ * SVpav_REIFY is only meaningful on such "fake" AVs (i.e. where SVpav_REAL
+ * is not set). It indicates that the fake AV is capable of becoming
+ * real if the array needs to be modified in some way. Functions that
+ * modify fake AVs check both flags to call av_reify() as appropriate.
+ *
+ * av_reify() transforms a fake AV into a real one through two actions.
+ * Allocated but unpopulated elements are initialized to make them safe for
+ * arbitrary retrieval and the reference counts of populated elements are
+ * incremented.
+ *
+ * Note that the Perl stack has neither flag set. (Thus,
+ * items that go on the stack are never refcounted.)
+ *
+ * These internal details are subject to change any time. AV
+ * manipulations external to perl should not care about any of this.
+ * GSAR 1999-09-10
+ */
-#define AVf_REAL 1 /* free old entries */
+/*
+=for apidoc ADmnU||Nullav
+Null AV pointer.
-#define Nullav Null(AV*)
+(deprecated - use C<(AV *)NULL> instead)
-#define AvMAGIC(av) ((XPVAV*) SvANY(av))->xav_magic
-#define AvARRAY(av) ((XPVAV*) SvANY(av))->xav_array
+=for apidoc Am|SSize_t|AvFILL|AV* av
+Same as C<L</av_top_index>> or C<L</av_tindex>>.
+
+=for apidoc Cm|SSize_t|AvFILLp|AV* av
+
+If the array C<av> is empty, this returns -1; otherwise it returns the maximum
+value of the indices of all the array elements which are currently defined in
+C<av>. It does not handle magic, hence the C<p> private indication in its name.
+
+=for apidoc Am|SV**|AvARRAY|AV* av
+Returns a pointer to the AV's internal SV* array.
+
+This is useful for doing pointer arithmetic on the array.
+If all you need is to look up an array element, then prefer C<av_fetch>.
+
+=cut
+*/
+
+#ifndef PERL_CORE
+# define Nullav Null(AV*)
+#endif
+
+#define AvARRAY(av) ((av)->sv_u.svu_array)
#define AvALLOC(av) ((XPVAV*) SvANY(av))->xav_alloc
#define AvMAX(av) ((XPVAV*) SvANY(av))->xav_max
-#define AvFILL(av) ((XPVAV*) SvANY(av))->xav_fill
-#define AvARYLEN(av) ((XPVAV*) SvANY(av))->xav_arylen
-#define AvFLAGS(av) ((XPVAV*) SvANY(av))->xav_flags
+#define AvFILLp(av) ((XPVAV*) SvANY(av))->xav_fill
+#define AvARYLEN(av) (*Perl_av_arylen_p(aTHX_ MUTABLE_AV(av)))
+
+#define AvREAL(av) (SvFLAGS(av) & SVpav_REAL)
+#define AvREAL_on(av) (SvFLAGS(av) |= SVpav_REAL)
+#define AvREAL_off(av) (SvFLAGS(av) &= ~SVpav_REAL)
+#define AvREAL_only(av) (AvREIFY_off(av), SvFLAGS(av) |= SVpav_REAL)
+#define AvREIFY(av) (SvFLAGS(av) & SVpav_REIFY)
+#define AvREIFY_on(av) (SvFLAGS(av) |= SVpav_REIFY)
+#define AvREIFY_off(av) (SvFLAGS(av) &= ~SVpav_REIFY)
+#define AvREIFY_only(av) (AvREAL_off(av), SvFLAGS(av) |= SVpav_REIFY)
+
+
+#define AvREALISH(av) (SvFLAGS(av) & (SVpav_REAL|SVpav_REIFY))
+
+#define AvFILL(av) ((SvRMAGICAL((const SV *) (av))) \
+ ? mg_size(MUTABLE_SV(av)) : AvFILLp(av))
+#define av_top_index(av) AvFILL(av)
+#define av_tindex(av) av_top_index(av)
+
+/* Note that it doesn't make sense to do this:
+ * SvGETMAGIC(av); IV x = av_tindex_nomg(av);
+ */
+# define av_top_index_skip_len_mg(av) \
+ (__ASSERT_(SvTYPE(av) == SVt_PVAV) AvFILLp(av))
+# define av_tindex_skip_len_mg(av) av_top_index_skip_len_mg(av)
+
+#define NEGATIVE_INDICES_VAR "NEGATIVE_INDICES"
+
+/*
+
+Note that there are both real and fake AVs; see the beginning of this file and
+'av.c'
+
+=for apidoc newAV
+=for apidoc_item newAV_alloc_x
+=for apidoc_item newAV_alloc_xz
+
+These all create a new AV, setting the reference count to 1. If you also know
+the initial elements of the array with, see L</C<av_make>>.
+
+As background, an array consists of three things:
+
+=over
+
+=item 1.
+
+A data structure containing information about the array as a whole, such as its
+size and reference count.
+
+=item 2.
+
+A C language array of pointers to the individual elements. These are treated
+as pointers to SVs, so all must be castable to SV*.
+
+=item 3.
-#define AvREAL(av) (((XPVAV*) SvANY(av))->xav_flags & AVf_REAL)
-#define AvREAL_on(av) (((XPVAV*) SvANY(av))->xav_flags |= AVf_REAL)
-#define AvREAL_off(av) (((XPVAV*) SvANY(av))->xav_flags &= ~AVf_REAL)
+The individual elements themselves. These could be, for instance, SVs and/or
+AVs and/or HVs, etc.
+
+=back
+
+An empty array need only have the first data structure, and all these functions
+create that. They differ in what else they do, as follows:
+
+=over
+
+=item C<newAV> form
+
+=for comment
+'form' above and below is because otherwise have two =items with the same name,
+can't link to them.
+
+This does nothing beyond creating the whole-array data structure.
+The Perl equivalent is approximately S<C<my @array;>>
+
+This is useful when the minimum size of the array could be zero (perhaps there
+are likely code paths that will entirely skip using it).
+
+If the array does get used, the pointers data structure will need to be
+allocated at that time. This will end up being done by L</av_extend>>,
+either explicitly:
+
+ av_extend(av, len);
+
+or implicitly when the first element is stored:
+
+ (void)av_store(av, 0, sv);
+
+Unused array elements are typically initialized by C<av_extend>.
+
+=item C<newAV_alloc_x> form
+
+This effectively does a C<newAV> followed by also allocating (uninitialized)
+space for the pointers array. This is used when you know ahead of time the
+likely minimum size of the array. It is more efficient to do this than doing a
+plain C<newAV> followed by an C<av_extend>.
+
+Of course the array can be extended later should it become necessary.
+
+C<size> must be at least 1.
+
+=item C<newAV_alloc_xz> form
+
+This is C<newAV_alloc_x>, but initializes each pointer in it to NULL. This
+gives added safety to guard against them being read before being set.
+
+C<size> must be at least 1.
+
+=back
+
+The following examples all result in an array that can fit four elements
+(indexes 0 .. 3):
+
+ AV *av = newAV();
+ av_extend(av, 3);
+
+ AV *av = newAV_alloc_x(4);
+
+ AV *av = newAV_alloc_xz(4);
+
+In contrast, the following examples allocate an array that is only guaranteed
+to fit one element without extending:
+
+ AV *av = newAV_alloc_x(1);
+ AV *av = newAV_alloc_xz(1);
+
+=cut
+
+*/
+
+#define newAV() MUTABLE_AV(newSV_type(SVt_PVAV))
+#define newAV_alloc_x(size) av_new_alloc(size,0)
+#define newAV_alloc_xz(size) av_new_alloc(size,1)
+
+/*
+ * ex: set ts=8 sts=4 sw=4 et:
+ */
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