source: trunk/third/perl/av.h @ 20075

/*    av.h
 *
 *    Copyright (C) 1991, 1992, 1993, 1995, 1996, 1997, 1998, 1999,
 *    2000, 2001, 2002, 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.
 *
 */

struct xpvav {
    char*       xav_array;      /* pointer to first array element */
    SSize_t     xav_fill;       /* Index of last element present */
    SSize_t     xav_max;        /* max index for which array has space */
    IV          xof_off;        /* ptr is incremented by offset */
    NV          xnv_nv;         /* numeric value, if any */
    MAGIC*      xmg_magic;      /* magic for scalar array */
    HV*         xmg_stash;      /* class package */

    SV**        xav_alloc;      /* pointer to beginning of C array of SVs */
    SV*         xav_arylen;
    U8          xav_flags;
};


/* AVf_REAL is set for all AVs whose xav_array contents are refcounted.
 * Some things like "@_" and the scratchpad list do not set this, to
 * indicate that they are cheating (for efficiency) by not refcounting
 * the AV's contents.
 * 
 * AVf_REIFY is only meaningful on such "fake" AVs (i.e. where AVf_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.
 *
 * Note that the Perl stack and @DB::args have 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 */
#define AVf_REIFY 2     /* can become real */

/* XXX this is not used anywhere */
#define AVf_REUSED 4    /* got undeffed--don't turn old memory into SVs now */

/*
=head1 Handy Values

=for apidoc AmU||Nullav
Null AV pointer.

=head1 Array Manipulation Functions

=for apidoc Am|int|AvFILL|AV* av
Same as C<av_len()>.  Deprecated, use C<av_len()> instead.

=cut
*/

#define Nullav Null(AV*)

#define AvARRAY(av)     ((SV**)((XPVAV*)  SvANY(av))->xav_array)
#define AvALLOC(av)     ((XPVAV*)  SvANY(av))->xav_alloc
#define AvMAX(av)       ((XPVAV*)  SvANY(av))->xav_max
#define AvFILLp(av)     ((XPVAV*)  SvANY(av))->xav_fill
#define AvARYLEN(av)    ((XPVAV*)  SvANY(av))->xav_arylen
#define AvFLAGS(av)     ((XPVAV*)  SvANY(av))->xav_flags

#define AvREAL(av)      (AvFLAGS(av) & AVf_REAL)
#define AvREAL_on(av)   (AvFLAGS(av) |= AVf_REAL)
#define AvREAL_off(av)  (AvFLAGS(av) &= ~AVf_REAL)
#define AvREIFY(av)     (AvFLAGS(av) & AVf_REIFY)
#define AvREIFY_on(av)  (AvFLAGS(av) |= AVf_REIFY)
#define AvREIFY_off(av) (AvFLAGS(av) &= ~AVf_REIFY)
#define AvREUSED(av)    (AvFLAGS(av) & AVf_REUSED)
#define AvREUSED_on(av) (AvFLAGS(av) |= AVf_REUSED)
#define AvREUSED_off(av) (AvFLAGS(av) &= ~AVf_REUSED)

#define AvREALISH(av)   (AvFLAGS(av) & (AVf_REAL|AVf_REIFY))
                                          
#define AvFILL(av)      ((SvRMAGICAL((SV *) (av))) \
                          ? mg_size((SV *) av) : AvFILLp(av))

#define NEGATIVE_INDICES_VAR "NEGATIVE_INDICES"