summaryrefslogtreecommitdiff
path: root/gnu/usr.bin/perl/av.c
blob: aada6c6b173cf84cfc080793d0636e4b7f65fdb5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
/*    av.c
 *
 *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
 *    2001, 2002, 2003, 2004, 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.
 *
 */

/*
 * '...for the Entwives desired order, and plenty, and peace (by which they
 *  meant that things should remain where they had set them).' --Treebeard
 *
 *     [p.476 of _The Lord of the Rings_, III/iv: "Treebeard"]
 */

/*
=head1 Array Manipulation Functions
*/

#include "EXTERN.h"
#define PERL_IN_AV_C
#include "perl.h"

void
Perl_av_reify(pTHX_ AV *av)
{
    dVAR;
    I32 key;

    PERL_ARGS_ASSERT_AV_REIFY;
    assert(SvTYPE(av) == SVt_PVAV);

    if (AvREAL(av))
	return;
#ifdef DEBUGGING
    if (SvTIED_mg((const SV *)av, PERL_MAGIC_tied))
	Perl_ck_warner_d(aTHX_ packWARN(WARN_DEBUGGING), "av_reify called on tied array");
#endif
    key = AvMAX(av) + 1;
    while (key > AvFILLp(av) + 1)
	AvARRAY(av)[--key] = &PL_sv_undef;
    while (key) {
	SV * const sv = AvARRAY(av)[--key];
	assert(sv);
	if (sv != &PL_sv_undef)
	    SvREFCNT_inc_simple_void_NN(sv);
    }
    key = AvARRAY(av) - AvALLOC(av);
    while (key)
	AvALLOC(av)[--key] = &PL_sv_undef;
    AvREIFY_off(av);
    AvREAL_on(av);
}

/*
=for apidoc av_extend

Pre-extend an array.  The C<key> is the index to which the array should be
extended.

=cut
*/

void
Perl_av_extend(pTHX_ AV *av, I32 key)
{
    dVAR;
    MAGIC *mg;

    PERL_ARGS_ASSERT_AV_EXTEND;
    assert(SvTYPE(av) == SVt_PVAV);

    mg = SvTIED_mg((const SV *)av, PERL_MAGIC_tied);
    if (mg) {
	SV *arg1 = sv_newmortal();
	sv_setiv(arg1, (IV)(key + 1));
	Perl_magic_methcall(aTHX_ MUTABLE_SV(av), mg, "EXTEND", G_DISCARD, 1,
			    arg1);
	return;
    }
    if (key > AvMAX(av)) {
	SV** ary;
	I32 tmp;
	I32 newmax;

	if (AvALLOC(av) != AvARRAY(av)) {
	    ary = AvALLOC(av) + AvFILLp(av) + 1;
	    tmp = AvARRAY(av) - AvALLOC(av);
	    Move(AvARRAY(av), AvALLOC(av), AvFILLp(av)+1, SV*);
	    AvMAX(av) += tmp;
	    AvARRAY(av) = AvALLOC(av);
	    if (AvREAL(av)) {
		while (tmp)
		    ary[--tmp] = &PL_sv_undef;
	    }
	    if (key > AvMAX(av) - 10) {
		newmax = key + AvMAX(av);
		goto resize;
	    }
	}
	else {
#ifdef PERL_MALLOC_WRAP
	    static const char oom_array_extend[] =
	      "Out of memory during array extend"; /* Duplicated in pp_hot.c */
#endif

	    if (AvALLOC(av)) {
#if !defined(STRANGE_MALLOC) && !defined(MYMALLOC)
		MEM_SIZE bytes;
		IV itmp;
#endif

#ifdef Perl_safesysmalloc_size
		/* Whilst it would be quite possible to move this logic around
		   (as I did in the SV code), so as to set AvMAX(av) early,
		   based on calling Perl_safesysmalloc_size() immediately after
		   allocation, I'm not convinced that it is a great idea here.
		   In an array we have to loop round setting everything to
		   &PL_sv_undef, which means writing to memory, potentially lots
		   of it, whereas for the SV buffer case we don't touch the
		   "bonus" memory. So there there is no cost in telling the
		   world about it, whereas here we have to do work before we can
		   tell the world about it, and that work involves writing to
		   memory that might never be read. So, I feel, better to keep
		   the current lazy system of only writing to it if our caller
		   has a need for more space. NWC  */
		newmax = Perl_safesysmalloc_size((void*)AvALLOC(av)) /
		    sizeof(const SV *) - 1;

		if (key <= newmax) 
		    goto resized;
#endif 
		newmax = key + AvMAX(av) / 5;
	      resize:
		MEM_WRAP_CHECK_1(newmax+1, SV*, oom_array_extend);
#if defined(STRANGE_MALLOC) || defined(MYMALLOC)
		Renew(AvALLOC(av),newmax+1, SV*);
#else
		bytes = (newmax + 1) * sizeof(const SV *);
#define MALLOC_OVERHEAD 16
		itmp = MALLOC_OVERHEAD;
		while ((MEM_SIZE)(itmp - MALLOC_OVERHEAD) < bytes)
		    itmp += itmp;
		itmp -= MALLOC_OVERHEAD;
		itmp /= sizeof(const SV *);
		assert(itmp > newmax);
		newmax = itmp - 1;
		assert(newmax >= AvMAX(av));
		Newx(ary, newmax+1, SV*);
		Copy(AvALLOC(av), ary, AvMAX(av)+1, SV*);
		Safefree(AvALLOC(av));
		AvALLOC(av) = ary;
#endif
#ifdef Perl_safesysmalloc_size
	      resized:
#endif
		ary = AvALLOC(av) + AvMAX(av) + 1;
		tmp = newmax - AvMAX(av);
		if (av == PL_curstack) {	/* Oops, grew stack (via av_store()?) */
		    PL_stack_sp = AvALLOC(av) + (PL_stack_sp - PL_stack_base);
		    PL_stack_base = AvALLOC(av);
		    PL_stack_max = PL_stack_base + newmax;
		}
	    }
	    else {
		newmax = key < 3 ? 3 : key;
		MEM_WRAP_CHECK_1(newmax+1, SV*, oom_array_extend);
		Newx(AvALLOC(av), newmax+1, SV*);
		ary = AvALLOC(av) + 1;
		tmp = newmax;
		AvALLOC(av)[0] = &PL_sv_undef;	/* For the stacks */
	    }
	    if (AvREAL(av)) {
		while (tmp)
		    ary[--tmp] = &PL_sv_undef;
	    }
	    
	    AvARRAY(av) = AvALLOC(av);
	    AvMAX(av) = newmax;
	}
    }
}

/*
=for apidoc av_fetch

Returns the SV at the specified index in the array.  The C<key> is the
index.  If lval is true, you are guaranteed to get a real SV back (in case
it wasn't real before), which you can then modify.  Check that the return
value is non-null before dereferencing it to a C<SV*>.

See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for
more information on how to use this function on tied arrays. 

The rough perl equivalent is C<$myarray[$idx]>.

=cut
*/

SV**
Perl_av_fetch(pTHX_ register AV *av, I32 key, I32 lval)
{
    dVAR;

    PERL_ARGS_ASSERT_AV_FETCH;
    assert(SvTYPE(av) == SVt_PVAV);

    if (SvRMAGICAL(av)) {
        const MAGIC * const tied_magic
	    = mg_find((const SV *)av, PERL_MAGIC_tied);
        if (tied_magic || mg_find((const SV *)av, PERL_MAGIC_regdata)) {
	    SV *sv;
	    if (key < 0) {
		I32 adjust_index = 1;
		if (tied_magic) {
		    /* Handle negative array indices 20020222 MJD */
		    SV * const * const negative_indices_glob =
			hv_fetch(SvSTASH(SvRV(SvTIED_obj(MUTABLE_SV(av),
							 tied_magic))),
				NEGATIVE_INDICES_VAR, 16, 0);

		    if (negative_indices_glob && SvTRUE(GvSV(*negative_indices_glob)))
			adjust_index = 0;
		}

		if (adjust_index) {
		    key += AvFILL(av) + 1;
		    if (key < 0)
			return NULL;
		}
	    }

            sv = sv_newmortal();
	    sv_upgrade(sv, SVt_PVLV);
	    mg_copy(MUTABLE_SV(av), sv, 0, key);
	    if (!tied_magic) /* for regdata, force leavesub to make copies */
		SvTEMP_off(sv);
	    LvTYPE(sv) = 't';
	    LvTARG(sv) = sv; /* fake (SV**) */
	    return &(LvTARG(sv));
        }
    }

    if (key < 0) {
	key += AvFILL(av) + 1;
	if (key < 0)
	    return NULL;
    }

    if (key > AvFILLp(av) || AvARRAY(av)[key] == &PL_sv_undef) {
      emptyness:
	return lval ? av_store(av,key,newSV(0)) : NULL;
    }

    if (AvREIFY(av)
	     && (!AvARRAY(av)[key]	/* eg. @_ could have freed elts */
		 || SvIS_FREED(AvARRAY(av)[key]))) {
	AvARRAY(av)[key] = &PL_sv_undef;	/* 1/2 reify */
	goto emptyness;
    }
    return &AvARRAY(av)[key];
}

/*
=for apidoc av_store

Stores an SV in an array.  The array index is specified as C<key>.  The
return value will be NULL if the operation failed or if the value did not
need to be actually stored within the array (as in the case of tied
arrays). Otherwise, it can be dereferenced
to get the C<SV*> that was stored
there (= C<val>)).

Note that the caller is responsible for suitably incrementing the reference
count of C<val> before the call, and decrementing it if the function
returned NULL.

Approximate Perl equivalent: C<$myarray[$key] = $val;>.

See L<perlguts/"Understanding the Magic of Tied Hashes and Arrays"> for
more information on how to use this function on tied arrays.

=cut
*/

SV**
Perl_av_store(pTHX_ register AV *av, I32 key, SV *val)
{
    dVAR;
    SV** ary;

    PERL_ARGS_ASSERT_AV_STORE;
    assert(SvTYPE(av) == SVt_PVAV);

    /* S_regclass relies on being able to pass in a NULL sv
       (unicode_alternate may be NULL).
    */

    if (!val)
	val = &PL_sv_undef;

    if (SvRMAGICAL(av)) {
        const MAGIC * const tied_magic = mg_find((const SV *)av, PERL_MAGIC_tied);
        if (tied_magic) {
            /* Handle negative array indices 20020222 MJD */
            if (key < 0) {
		bool adjust_index = 1;
		SV * const * const negative_indices_glob =
                    hv_fetch(SvSTASH(SvRV(SvTIED_obj(MUTABLE_SV(av), 
                                                     tied_magic))), 
                             NEGATIVE_INDICES_VAR, 16, 0);
                if (negative_indices_glob
                    && SvTRUE(GvSV(*negative_indices_glob)))
                    adjust_index = 0;
                if (adjust_index) {
                    key += AvFILL(av) + 1;
                    if (key < 0)
                        return 0;
                }
            }
	    if (val != &PL_sv_undef) {
		mg_copy(MUTABLE_SV(av), val, 0, key);
	    }
	    return NULL;
        }
    }


    if (key < 0) {
	key += AvFILL(av) + 1;
	if (key < 0)
	    return NULL;
    }

    if (SvREADONLY(av) && key >= AvFILL(av))
	Perl_croak_no_modify(aTHX);

    if (!AvREAL(av) && AvREIFY(av))
	av_reify(av);
    if (key > AvMAX(av))
	av_extend(av,key);
    ary = AvARRAY(av);
    if (AvFILLp(av) < key) {
	if (!AvREAL(av)) {
	    if (av == PL_curstack && key > PL_stack_sp - PL_stack_base)
		PL_stack_sp = PL_stack_base + key;	/* XPUSH in disguise */
	    do {
		ary[++AvFILLp(av)] = &PL_sv_undef;
	    } while (AvFILLp(av) < key);
	}
	AvFILLp(av) = key;
    }
    else if (AvREAL(av))
	SvREFCNT_dec(ary[key]);
    ary[key] = val;
    if (SvSMAGICAL(av)) {
	const MAGIC *mg = SvMAGIC(av);
	bool set = TRUE;
	for (; mg; mg = mg->mg_moremagic) {
	  if (!isUPPER(mg->mg_type)) continue;
	  if (val != &PL_sv_undef) {
	    sv_magic(val, MUTABLE_SV(av), toLOWER(mg->mg_type), 0, key);
	  }
	  if (PL_delaymagic && mg->mg_type == PERL_MAGIC_isa) {
	    PL_delaymagic |= DM_ARRAY_ISA;
	    set = FALSE;
	  }
	}
	if (set)
	   mg_set(MUTABLE_SV(av));
    }
    return &ary[key];
}

/*
=for apidoc av_make

Creates a new AV and populates it with a list of SVs.  The SVs are copied
into the array, so they may be freed after the call to av_make.  The new AV
will have a reference count of 1.

Perl equivalent: C<my @new_array = ($scalar1, $scalar2, $scalar3...);>

=cut
*/

AV *
Perl_av_make(pTHX_ register I32 size, register SV **strp)
{
    register AV * const av = MUTABLE_AV(newSV_type(SVt_PVAV));
    /* sv_upgrade does AvREAL_only()  */
    PERL_ARGS_ASSERT_AV_MAKE;
    assert(SvTYPE(av) == SVt_PVAV);

    if (size) {		/* "defined" was returning undef for size==0 anyway. */
        register SV** ary;
        register I32 i;
	Newx(ary,size,SV*);
	AvALLOC(av) = ary;
	AvARRAY(av) = ary;
	AvFILLp(av) = AvMAX(av) = size - 1;
	for (i = 0; i < size; i++) {
	    assert (*strp);

	    /* Don't let sv_setsv swipe, since our source array might
	       have multiple references to the same temp scalar (e.g.
	       from a list slice) */

	    ary[i] = newSV(0);
	    sv_setsv_flags(ary[i], *strp,
			   SV_GMAGIC|SV_DO_COW_SVSETSV|SV_NOSTEAL);
	    strp++;
	}
    }
    return av;
}

/*
=for apidoc av_clear

Clears an array, making it empty.  Does not free the memory the av uses to
store its list of scalars.  If any destructors are triggered as a result,
the av itself may be freed when this function returns.

Perl equivalent: C<@myarray = ();>.

=cut
*/

void
Perl_av_clear(pTHX_ register AV *av)
{
    dVAR;
    I32 extra;
    bool real;

    PERL_ARGS_ASSERT_AV_CLEAR;
    assert(SvTYPE(av) == SVt_PVAV);

#ifdef DEBUGGING
    if (SvREFCNT(av) == 0) {
	Perl_ck_warner_d(aTHX_ packWARN(WARN_DEBUGGING), "Attempt to clear deleted array");
    }
#endif

    if (SvREADONLY(av))
	Perl_croak_no_modify(aTHX);

    /* Give any tie a chance to cleanup first */
    if (SvRMAGICAL(av)) {
	const MAGIC* const mg = SvMAGIC(av);
	if (PL_delaymagic && mg && mg->mg_type == PERL_MAGIC_isa)
	    PL_delaymagic |= DM_ARRAY_ISA;
        else
	    mg_clear(MUTABLE_SV(av)); 
    }

    if (AvMAX(av) < 0)
	return;

    if ((real = !!AvREAL(av))) {
	SV** const ary = AvARRAY(av);
	I32 index = AvFILLp(av) + 1;
	ENTER;
	SAVEFREESV(SvREFCNT_inc_simple_NN(av));
	while (index) {
	    SV * const sv = ary[--index];
	    /* undef the slot before freeing the value, because a
	     * destructor might try to modify this array */
	    ary[index] = &PL_sv_undef;
	    SvREFCNT_dec(sv);
	}
    }
    extra = AvARRAY(av) - AvALLOC(av);
    if (extra) {
	AvMAX(av) += extra;
	AvARRAY(av) = AvALLOC(av);
    }
    AvFILLp(av) = -1;
    if (real) LEAVE;
}

/*
=for apidoc av_undef

Undefines the array.  Frees the memory used by the av to store its list of
scalars.  If any destructors are triggered as a result, the av itself may
be freed.

=cut
*/

void
Perl_av_undef(pTHX_ register AV *av)
{
    bool real;

    PERL_ARGS_ASSERT_AV_UNDEF;
    assert(SvTYPE(av) == SVt_PVAV);

    /* Give any tie a chance to cleanup first */
    if (SvTIED_mg((const SV *)av, PERL_MAGIC_tied)) 
	av_fill(av, -1);

    if ((real = !!AvREAL(av))) {
	register I32 key = AvFILLp(av) + 1;
	ENTER;
	SAVEFREESV(SvREFCNT_inc_simple_NN(av));
	while (key)
	    SvREFCNT_dec(AvARRAY(av)[--key]);
    }

    Safefree(AvALLOC(av));
    AvALLOC(av) = NULL;
    AvARRAY(av) = NULL;
    AvMAX(av) = AvFILLp(av) = -1;

    if(SvRMAGICAL(av)) mg_clear(MUTABLE_SV(av));
    if(real) LEAVE;
}

/*

=for apidoc av_create_and_push

Push an SV onto the end of the array, creating the array if necessary.
A small internal helper function to remove a commonly duplicated idiom.

=cut
*/

void
Perl_av_create_and_push(pTHX_ AV **const avp, SV *const val)
{
    PERL_ARGS_ASSERT_AV_CREATE_AND_PUSH;

    if (!*avp)
	*avp = newAV();
    av_push(*avp, val);
}

/*
=for apidoc av_push

Pushes an SV onto the end of the array.  The array will grow automatically
to accommodate the addition.  This takes ownership of one reference count.

Perl equivalent: C<push @myarray, $elem;>.

=cut
*/

void
Perl_av_push(pTHX_ register AV *av, SV *val)
{             
    dVAR;
    MAGIC *mg;

    PERL_ARGS_ASSERT_AV_PUSH;
    assert(SvTYPE(av) == SVt_PVAV);

    if (SvREADONLY(av))
	Perl_croak_no_modify(aTHX);

    if ((mg = SvTIED_mg((const SV *)av, PERL_MAGIC_tied))) {
	Perl_magic_methcall(aTHX_ MUTABLE_SV(av), mg, "PUSH", G_DISCARD, 1,
			    val);
	return;
    }
    av_store(av,AvFILLp(av)+1,val);
}

/*
=for apidoc av_pop

Pops an SV off the end of the array.  Returns C<&PL_sv_undef> if the array
is empty.

Perl equivalent: C<pop(@myarray);>

=cut
*/

SV *
Perl_av_pop(pTHX_ register AV *av)
{
    dVAR;
    SV *retval;
    MAGIC* mg;

    PERL_ARGS_ASSERT_AV_POP;
    assert(SvTYPE(av) == SVt_PVAV);

    if (SvREADONLY(av))
	Perl_croak_no_modify(aTHX);
    if ((mg = SvTIED_mg((const SV *)av, PERL_MAGIC_tied))) {
	retval = Perl_magic_methcall(aTHX_ MUTABLE_SV(av), mg, "POP", 0, 0);
	if (retval)
	    retval = newSVsv(retval);
	return retval;
    }
    if (AvFILL(av) < 0)
	return &PL_sv_undef;
    retval = AvARRAY(av)[AvFILLp(av)];
    AvARRAY(av)[AvFILLp(av)--] = &PL_sv_undef;
    if (SvSMAGICAL(av))
	mg_set(MUTABLE_SV(av));
    return retval;
}

/*

=for apidoc av_create_and_unshift_one

Unshifts an SV onto the beginning of the array, creating the array if
necessary.
A small internal helper function to remove a commonly duplicated idiom.

=cut
*/

SV **
Perl_av_create_and_unshift_one(pTHX_ AV **const avp, SV *const val)
{
    PERL_ARGS_ASSERT_AV_CREATE_AND_UNSHIFT_ONE;

    if (!*avp)
	*avp = newAV();
    av_unshift(*avp, 1);
    return av_store(*avp, 0, val);
}

/*
=for apidoc av_unshift

Unshift the given number of C<undef> values onto the beginning of the
array.  The array will grow automatically to accommodate the addition.  You
must then use C<av_store> to assign values to these new elements.

Perl equivalent: C<unshift @myarray, ( (undef) x $n );>
    
=cut
*/

void
Perl_av_unshift(pTHX_ register AV *av, register I32 num)
{
    dVAR;
    register I32 i;
    MAGIC* mg;

    PERL_ARGS_ASSERT_AV_UNSHIFT;
    assert(SvTYPE(av) == SVt_PVAV);

    if (SvREADONLY(av))
	Perl_croak_no_modify(aTHX);

    if ((mg = SvTIED_mg((const SV *)av, PERL_MAGIC_tied))) {
	Perl_magic_methcall(aTHX_ MUTABLE_SV(av), mg, "UNSHIFT",
			    G_DISCARD | G_UNDEF_FILL, num);
	return;
    }

    if (num <= 0)
      return;
    if (!AvREAL(av) && AvREIFY(av))
	av_reify(av);
    i = AvARRAY(av) - AvALLOC(av);
    if (i) {
	if (i > num)
	    i = num;
	num -= i;
    
	AvMAX(av) += i;
	AvFILLp(av) += i;
	AvARRAY(av) = AvARRAY(av) - i;
    }
    if (num) {
	register SV **ary;
	const I32 i = AvFILLp(av);
	/* Create extra elements */
	const I32 slide = i > 0 ? i : 0;
	num += slide;
	av_extend(av, i + num);
	AvFILLp(av) += num;
	ary = AvARRAY(av);
	Move(ary, ary + num, i + 1, SV*);
	do {
	    ary[--num] = &PL_sv_undef;
	} while (num);
	/* Make extra elements into a buffer */
	AvMAX(av) -= slide;
	AvFILLp(av) -= slide;
	AvARRAY(av) = AvARRAY(av) + slide;
    }
}

/*
=for apidoc av_shift

Shifts an SV off the beginning of the
array.  Returns C<&PL_sv_undef> if the 
array is empty.

Perl equivalent: C<shift(@myarray);>

=cut
*/

SV *
Perl_av_shift(pTHX_ register AV *av)
{
    dVAR;
    SV *retval;
    MAGIC* mg;

    PERL_ARGS_ASSERT_AV_SHIFT;
    assert(SvTYPE(av) == SVt_PVAV);

    if (SvREADONLY(av))
	Perl_croak_no_modify(aTHX);
    if ((mg = SvTIED_mg((const SV *)av, PERL_MAGIC_tied))) {
	retval = Perl_magic_methcall(aTHX_ MUTABLE_SV(av), mg, "SHIFT", 0, 0);
	if (retval)
	    retval = newSVsv(retval);
	return retval;
    }
    if (AvFILL(av) < 0)
      return &PL_sv_undef;
    retval = *AvARRAY(av);
    if (AvREAL(av))
	*AvARRAY(av) = &PL_sv_undef;
    AvARRAY(av) = AvARRAY(av) + 1;
    AvMAX(av)--;
    AvFILLp(av)--;
    if (SvSMAGICAL(av))
	mg_set(MUTABLE_SV(av));
    return retval;
}

/*
=for apidoc av_len

Returns the highest index in the array.  The number of elements in the
array is C<av_len(av) + 1>.  Returns -1 if the array is empty.

The Perl equivalent for this is C<$#myarray>.

=cut
*/

I32
Perl_av_len(pTHX_ AV *av)
{
    PERL_ARGS_ASSERT_AV_LEN;
    assert(SvTYPE(av) == SVt_PVAV);

    return AvFILL(av);
}

/*
=for apidoc av_fill

Set the highest index in the array to the given number, equivalent to
Perl's C<$#array = $fill;>.

The number of elements in the an array will be C<fill + 1> after
av_fill() returns.  If the array was previously shorter, then the
additional elements appended are set to C<PL_sv_undef>.  If the array
was longer, then the excess elements are freed.  C<av_fill(av, -1)> is
the same as C<av_clear(av)>.

=cut
*/
void
Perl_av_fill(pTHX_ register AV *av, I32 fill)
{
    dVAR;
    MAGIC *mg;

    PERL_ARGS_ASSERT_AV_FILL;
    assert(SvTYPE(av) == SVt_PVAV);

    if (fill < 0)
	fill = -1;
    if ((mg = SvTIED_mg((const SV *)av, PERL_MAGIC_tied))) {
	SV *arg1 = sv_newmortal();
	sv_setiv(arg1, (IV)(fill + 1));
	Perl_magic_methcall(aTHX_ MUTABLE_SV(av), mg, "STORESIZE", G_DISCARD,
			    1, arg1);
	return;
    }
    if (fill <= AvMAX(av)) {
	I32 key = AvFILLp(av);
	SV** const ary = AvARRAY(av);

	if (AvREAL(av)) {
	    while (key > fill) {
		SvREFCNT_dec(ary[key]);
		ary[key--] = &PL_sv_undef;
	    }
	}
	else {
	    while (key < fill)
		ary[++key] = &PL_sv_undef;
	}
	    
	AvFILLp(av) = fill;
	if (SvSMAGICAL(av))
	    mg_set(MUTABLE_SV(av));
    }
    else
	(void)av_store(av,fill,&PL_sv_undef);
}

/*
=for apidoc av_delete

Deletes the element indexed by C<key> from the array, makes the element mortal,
and returns it.  If C<flags> equals C<G_DISCARD>, the element is freed and null
is returned.  Perl equivalent: C<my $elem = delete($myarray[$idx]);> for the
non-C<G_DISCARD> version and a void-context C<delete($myarray[$idx]);> for the
C<G_DISCARD> version.

=cut
*/
SV *
Perl_av_delete(pTHX_ AV *av, I32 key, I32 flags)
{
    dVAR;
    SV *sv;

    PERL_ARGS_ASSERT_AV_DELETE;
    assert(SvTYPE(av) == SVt_PVAV);

    if (SvREADONLY(av))
	Perl_croak_no_modify(aTHX);

    if (SvRMAGICAL(av)) {
        const MAGIC * const tied_magic
	    = mg_find((const SV *)av, PERL_MAGIC_tied);
        if ((tied_magic || mg_find((const SV *)av, PERL_MAGIC_regdata))) {
            /* Handle negative array indices 20020222 MJD */
            SV **svp;
            if (key < 0) {
                unsigned adjust_index = 1;
                if (tied_magic) {
		    SV * const * const negative_indices_glob =
                        hv_fetch(SvSTASH(SvRV(SvTIED_obj(MUTABLE_SV(av), 
                                                         tied_magic))), 
                                 NEGATIVE_INDICES_VAR, 16, 0);
                    if (negative_indices_glob
                        && SvTRUE(GvSV(*negative_indices_glob)))
                        adjust_index = 0;
                }
                if (adjust_index) {
                    key += AvFILL(av) + 1;
                    if (key < 0)
			return NULL;
                }
            }
            svp = av_fetch(av, key, TRUE);
            if (svp) {
                sv = *svp;
                mg_clear(sv);
                if (mg_find(sv, PERL_MAGIC_tiedelem)) {
                    sv_unmagic(sv, PERL_MAGIC_tiedelem); /* No longer an element */
                    return sv;
                }
		return NULL;
            }
        }
    }

    if (key < 0) {
	key += AvFILL(av) + 1;
	if (key < 0)
	    return NULL;
    }

    if (key > AvFILLp(av))
	return NULL;
    else {
	if (!AvREAL(av) && AvREIFY(av))
	    av_reify(av);
	sv = AvARRAY(av)[key];
	if (key == AvFILLp(av)) {
	    AvARRAY(av)[key] = &PL_sv_undef;
	    do {
		AvFILLp(av)--;
	    } while (--key >= 0 && AvARRAY(av)[key] == &PL_sv_undef);
	}
	else
	    AvARRAY(av)[key] = &PL_sv_undef;
	if (SvSMAGICAL(av))
	    mg_set(MUTABLE_SV(av));
    }
    if (flags & G_DISCARD) {
	SvREFCNT_dec(sv);
	sv = NULL;
    }
    else if (AvREAL(av))
	sv = sv_2mortal(sv);
    return sv;
}

/*
=for apidoc av_exists

Returns true if the element indexed by C<key> has been initialized.

This relies on the fact that uninitialized array elements are set to
C<&PL_sv_undef>.

Perl equivalent: C<exists($myarray[$key])>.

=cut
*/
bool
Perl_av_exists(pTHX_ AV *av, I32 key)
{
    dVAR;
    PERL_ARGS_ASSERT_AV_EXISTS;
    assert(SvTYPE(av) == SVt_PVAV);

    if (SvRMAGICAL(av)) {
        const MAGIC * const tied_magic
	    = mg_find((const SV *)av, PERL_MAGIC_tied);
        const MAGIC * const regdata_magic
            = mg_find((const SV *)av, PERL_MAGIC_regdata);
        if (tied_magic || regdata_magic) {
	    SV * const sv = sv_newmortal();
            MAGIC *mg;
            /* Handle negative array indices 20020222 MJD */
            if (key < 0) {
                unsigned adjust_index = 1;
                if (tied_magic) {
		    SV * const * const negative_indices_glob =
                        hv_fetch(SvSTASH(SvRV(SvTIED_obj(MUTABLE_SV(av), 
                                                         tied_magic))), 
                                 NEGATIVE_INDICES_VAR, 16, 0);
                    if (negative_indices_glob
                        && SvTRUE(GvSV(*negative_indices_glob)))
                        adjust_index = 0;
                }
                if (adjust_index) {
                    key += AvFILL(av) + 1;
                    if (key < 0)
                        return FALSE;
                    else
                        return TRUE;
                }
            }

            if(key >= 0 && regdata_magic) {
                if (key <= AvFILL(av))
                    return TRUE;
                else
                    return FALSE;
            }

            mg_copy(MUTABLE_SV(av), sv, 0, key);
            mg = mg_find(sv, PERL_MAGIC_tiedelem);
            if (mg) {
                magic_existspack(sv, mg);
                return cBOOL(SvTRUE(sv));
            }

        }
    }

    if (key < 0) {
	key += AvFILL(av) + 1;
	if (key < 0)
	    return FALSE;
    }

    if (key <= AvFILLp(av) && AvARRAY(av)[key] != &PL_sv_undef
	&& AvARRAY(av)[key])
    {
	return TRUE;
    }
    else
	return FALSE;
}

static MAGIC *
S_get_aux_mg(pTHX_ AV *av) {
    dVAR;
    MAGIC *mg;

    PERL_ARGS_ASSERT_GET_AUX_MG;
    assert(SvTYPE(av) == SVt_PVAV);

    mg = mg_find((const SV *)av, PERL_MAGIC_arylen_p);

    if (!mg) {
	mg = sv_magicext(MUTABLE_SV(av), 0, PERL_MAGIC_arylen_p,
			 &PL_vtbl_arylen_p, 0, 0);
	assert(mg);
	/* sv_magicext won't set this for us because we pass in a NULL obj  */
	mg->mg_flags |= MGf_REFCOUNTED;
    }
    return mg;
}

SV **
Perl_av_arylen_p(pTHX_ AV *av) {
    MAGIC *const mg = get_aux_mg(av);

    PERL_ARGS_ASSERT_AV_ARYLEN_P;
    assert(SvTYPE(av) == SVt_PVAV);

    return &(mg->mg_obj);
}

IV *
Perl_av_iter_p(pTHX_ AV *av) {
    MAGIC *const mg = get_aux_mg(av);

    PERL_ARGS_ASSERT_AV_ITER_P;
    assert(SvTYPE(av) == SVt_PVAV);

#if IVSIZE == I32SIZE
    return (IV *)&(mg->mg_len);
#else
    if (!mg->mg_ptr) {
	IV *temp;
	mg->mg_len = IVSIZE;
	Newxz(temp, 1, IV);
	mg->mg_ptr = (char *) temp;
    }
    return (IV *)mg->mg_ptr;
#endif
}

/*
 * Local variables:
 * c-indentation-style: bsd
 * c-basic-offset: 4
 * indent-tabs-mode: t
 * End:
 *
 * ex: set ts=8 sts=4 sw=4 noet:
 */