summaryrefslogtreecommitdiff
path: root/gnu/usr.bin/perl/ext/PerlIO-encoding/encoding.xs
blob: f1b074235c894e9c10821dbb6553fcfcffd3759f (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
/*
 * $Id: encoding.xs,v 0.3 2002/04/21 22:14:41 dankogai Exp $
 */

#define PERL_NO_GET_CONTEXT
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#define U8 U8

#define OUR_DEFAULT_FB	"Encode::PERLQQ"

#if defined(USE_PERLIO) && !defined(USE_SFIO)

/* Define an encoding "layer" in the perliol.h sense.

   The layer defined here "inherits" in an object-oriented sense from
   the "perlio" layer with its PerlIOBuf_* "methods".  The
   implementation is particularly efficient as until Encode settles
   down there is no point in tryint to tune it.

   The layer works by overloading the "fill" and "flush" methods.

   "fill" calls "SUPER::fill" in perl terms, then calls the encode OO
   perl API to convert the encoded data to UTF-8 form, then copies it
   back to the buffer. The "base class's" read methods then see the
   UTF-8 data.

   "flush" transforms the UTF-8 data deposited by the "base class's
   write method in the buffer back into the encoded form using the
   encode OO perl API, then copies data back into the buffer and calls
   "SUPER::flush.

   Note that "flush" is _also_ called for read mode - we still do the
   (back)-translate so that the base class's "flush" sees the
   correct number of encoded chars for positioning the seek
   pointer. (This double translation is the worst performance issue -
   particularly with all-perl encode engine.)

*/

#include "perliol.h"

typedef struct {
    PerlIOBuf base;		/* PerlIOBuf stuff */
    SV *bufsv;			/* buffer seen by layers above */
    SV *dataSV;			/* data we have read from layer below */
    SV *enc;			/* the encoding object */
    SV *chk;                    /* CHECK in Encode methods */
    int flags;			/* Flags currently just needs lines */
    int inEncodeCall;		/* trap recursive encode calls */
} PerlIOEncode;

#define NEEDS_LINES	1

SV *
PerlIOEncode_getarg(pTHX_ PerlIO * f, CLONE_PARAMS * param, int flags)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    SV *sv = &PL_sv_undef;
    if (e->enc) {
	dSP;
	/* Not 100% sure stack swap is right thing to do during dup ... */
	PUSHSTACKi(PERLSI_MAGIC);
	SPAGAIN;
	ENTER;
	SAVETMPS;
	PUSHMARK(sp);
	XPUSHs(e->enc);
	PUTBACK;
	if (call_method("name", G_SCALAR) == 1) {
	    SPAGAIN;
	    sv = newSVsv(POPs);
	    PUTBACK;
	}
	FREETMPS;
	LEAVE;
	POPSTACK;
    }
    return sv;
}

IV
PerlIOEncode_pushed(pTHX_ PerlIO * f, const char *mode, SV * arg, PerlIO_funcs *tab)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    dSP;
    IV  code = PerlIOBuf_pushed(aTHX_ f, mode, Nullsv,tab);
    SV *result = Nullsv;

    PUSHSTACKi(PERLSI_MAGIC);
    SPAGAIN;

    ENTER;
    SAVETMPS;

    PUSHMARK(sp);
    XPUSHs(arg);
    PUTBACK;
    if (call_pv("Encode::find_encoding", G_SCALAR) != 1) {
	/* should never happen */
	Perl_die(aTHX_ "Encode::find_encoding did not return a value");
	return -1;
    }
    SPAGAIN;
    result = POPs;
    PUTBACK;

    if (!SvROK(result) || !SvOBJECT(SvRV(result))) {
	e->enc = Nullsv;
	Perl_warner(aTHX_ packWARN(WARN_IO), "Cannot find encoding \"%" SVf "\"",
		    arg);
	errno = EINVAL;
	code = -1;
    }
    else {

       /* $enc->renew */
	PUSHMARK(sp);
	XPUSHs(result);
	PUTBACK;
	if (call_method("renew",G_SCALAR|G_EVAL) != 1 || SvTRUE(ERRSV)) {
	    Perl_warner(aTHX_ packWARN(WARN_IO), "\"%" SVf "\" does not support renew method",
			arg);
	}
	else {
	    SPAGAIN;
	    result = POPs;
	    PUTBACK;
	}
	e->enc = newSVsv(result);
	PUSHMARK(sp);
	XPUSHs(e->enc);
	PUTBACK;
	if (call_method("needs_lines",G_SCALAR|G_EVAL) != 1 || SvTRUE(ERRSV)) {
	    Perl_warner(aTHX_ packWARN(WARN_IO), "\"%" SVf "\" does not support needs_lines",
			arg);
	}
	else {
	    SPAGAIN;
	    result = POPs;
	    PUTBACK;
	    if (SvTRUE(result)) {
		e->flags |= NEEDS_LINES;
	    }
	}
	PerlIOBase(f)->flags |= PERLIO_F_UTF8;
    }

    e->chk = newSVsv(get_sv("PerlIO::encoding::fallback", 0));
    e->inEncodeCall = 0;

    FREETMPS;
    LEAVE;
    POPSTACK;
    return code;
}

IV
PerlIOEncode_popped(pTHX_ PerlIO * f)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    if (e->enc) {
	SvREFCNT_dec(e->enc);
	e->enc = Nullsv;
    }
    if (e->bufsv) {
	SvREFCNT_dec(e->bufsv);
	e->bufsv = Nullsv;
    }
    if (e->dataSV) {
	SvREFCNT_dec(e->dataSV);
	e->dataSV = Nullsv;
    }
    if (e->chk) {
	SvREFCNT_dec(e->chk);
	e->chk = Nullsv;
    }
    return 0;
}

STDCHAR *
PerlIOEncode_get_base(pTHX_ PerlIO * f)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    if (!e->base.bufsiz)
	e->base.bufsiz = 1024;
    if (!e->bufsv) {
	e->bufsv = newSV(e->base.bufsiz);
	sv_setpvn(e->bufsv, "", 0);
    }
    e->base.buf = (STDCHAR *) SvPVX(e->bufsv);
    if (!e->base.ptr)
	e->base.ptr = e->base.buf;
    if (!e->base.end)
	e->base.end = e->base.buf;
    if (e->base.ptr < e->base.buf
	|| e->base.ptr > e->base.buf + SvLEN(e->bufsv)) {
	Perl_warn(aTHX_ " ptr %p(%p)%p", e->base.buf, e->base.ptr,
		  e->base.buf + SvLEN(e->bufsv));
	abort();
    }
    if (SvLEN(e->bufsv) < e->base.bufsiz) {
	SSize_t poff = e->base.ptr - e->base.buf;
	SSize_t eoff = e->base.end - e->base.buf;
	e->base.buf = (STDCHAR *) SvGROW(e->bufsv, e->base.bufsiz);
	e->base.ptr = e->base.buf + poff;
	e->base.end = e->base.buf + eoff;
    }
    if (e->base.ptr < e->base.buf
	|| e->base.ptr > e->base.buf + SvLEN(e->bufsv)) {
	Perl_warn(aTHX_ " ptr %p(%p)%p", e->base.buf, e->base.ptr,
		  e->base.buf + SvLEN(e->bufsv));
	abort();
    }
    return e->base.buf;
}

IV
PerlIOEncode_fill(pTHX_ PerlIO * f)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    dSP;
    IV code = 0;
    PerlIO *n;
    SSize_t avail;

    if (PerlIO_flush(f) != 0)
	return -1;
    n  = PerlIONext(f);
    if (!PerlIO_fast_gets(n)) {
	/* Things get too messy if we don't have a buffer layer
	   push a :perlio to do the job */
	char mode[8];
	n  = PerlIO_push(aTHX_ n, &PerlIO_perlio, PerlIO_modestr(f,mode), Nullsv);
	if (!n) {
	    Perl_die(aTHX_ "panic: cannot push :perlio for %p",f);
	}
    }
    PUSHSTACKi(PERLSI_MAGIC);
    SPAGAIN;
    ENTER;
    SAVETMPS;
  retry:
    avail = PerlIO_get_cnt(n);
    if (avail <= 0) {
	avail = PerlIO_fill(n);
	if (avail == 0) {
	    avail = PerlIO_get_cnt(n);
	}
	else {
	    if (!PerlIO_error(n) && PerlIO_eof(n))
		avail = 0;
	}
    }
    if (avail > 0 || (e->flags & NEEDS_LINES)) {
	STDCHAR *ptr = PerlIO_get_ptr(n);
	SSize_t use  = (avail >= 0) ? avail : 0;
	SV *uni;
	char *s = NULL;
	STRLEN len = 0;
	e->base.ptr = e->base.end = (STDCHAR *) NULL;
	(void) PerlIOEncode_get_base(aTHX_ f);
	if (!e->dataSV)
	    e->dataSV = newSV(0);
	if (SvTYPE(e->dataSV) < SVt_PV) {
	    sv_upgrade(e->dataSV,SVt_PV);
	}
	if (e->flags & NEEDS_LINES) {
	    /* Encoding needs whole lines (e.g. iso-2022-*)
	       search back from end of available data for
	       and line marker
	     */
	    STDCHAR *nl = ptr+use-1;
	    while (nl >= ptr) {
		if (*nl == '\n') {
		    break;
		}
		nl--;
	    }
	    if (nl >= ptr && *nl == '\n') {
		/* found a line - take up to and including that */
		use = (nl+1)-ptr;
	    }
	    else if (avail > 0) {
		/* No line, but not EOF - append avail to the pending data */
		sv_catpvn(e->dataSV, (char*)ptr, use);
		PerlIO_set_ptrcnt(n, ptr+use, 0);
		goto retry;
	    }
	    else if (!SvCUR(e->dataSV)) {
		goto end_of_file;
	    }
	}
	if (SvCUR(e->dataSV)) {
	    /* something left over from last time - create a normal
	       SV with new data appended
	     */
	    if (use + SvCUR(e->dataSV) > e->base.bufsiz) {
		if (e->flags & NEEDS_LINES) {
		    /* Have to grow buffer */
		    e->base.bufsiz = use + SvCUR(e->dataSV);
		    PerlIOEncode_get_base(aTHX_ f);
		}
		else {
	       use = e->base.bufsiz - SvCUR(e->dataSV);
	    }
	    }
	    sv_catpvn(e->dataSV,(char*)ptr,use);
	}
	else {
	    /* Create a "dummy" SV to represent the available data from layer below */
	    if (SvLEN(e->dataSV) && SvPVX_const(e->dataSV)) {
		Safefree(SvPVX_mutable(e->dataSV));
	    }
	    if (use > (SSize_t)e->base.bufsiz) {
		if (e->flags & NEEDS_LINES) {
		    /* Have to grow buffer */
		    e->base.bufsiz = use;
		    PerlIOEncode_get_base(aTHX_ f);
		}
		else {
	       use = e->base.bufsiz;
	    }
	    }
	    SvPV_set(e->dataSV, (char *) ptr);
	    SvLEN_set(e->dataSV, 0);  /* Hands off sv.c - it isn't yours */
	    SvCUR_set(e->dataSV,use);
	    SvPOK_only(e->dataSV);
	}
	SvUTF8_off(e->dataSV);
	PUSHMARK(sp);
	XPUSHs(e->enc);
	XPUSHs(e->dataSV);
	XPUSHs(e->chk);
	PUTBACK;
	if (call_method("decode", G_SCALAR) != 1) {
	    Perl_die(aTHX_ "panic: decode did not return a value");
	}
	SPAGAIN;
	uni = POPs;
	PUTBACK;
	/* Now get translated string (forced to UTF-8) and use as buffer */
	if (SvPOK(uni)) {
	    s = SvPVutf8(uni, len);
#ifdef PARANOID_ENCODE_CHECKS
	    if (len && !is_utf8_string((U8*)s,len)) {
		Perl_warn(aTHX_ "panic: decode did not return UTF-8 '%.*s'",(int) len,s);
	    }
#endif
	}
	if (len > 0) {
	    /* Got _something */
	    /* if decode gave us back dataSV then data may vanish when
	       we do ptrcnt adjust - so take our copy now.
	       (The copy is a pain - need a put-it-here option for decode.)
	     */
	    sv_setpvn(e->bufsv,s,len);
	    e->base.ptr = e->base.buf = (STDCHAR*)SvPVX(e->bufsv);
	    e->base.end = e->base.ptr + SvCUR(e->bufsv);
	    PerlIOBase(f)->flags |= PERLIO_F_RDBUF;
	    SvUTF8_on(e->bufsv);

	    /* Adjust ptr/cnt not taking anything which
	       did not translate - not clear this is a win */
	    /* compute amount we took */
	    use -= SvCUR(e->dataSV);
	    PerlIO_set_ptrcnt(n, ptr+use, (avail-use));
	    /* and as we did not take it it isn't pending */
	    SvCUR_set(e->dataSV,0);
	} else {
	    /* Got nothing - assume partial character so we need some more */
	    /* Make sure e->dataSV is a normal SV before re-filling as
	       buffer alias will change under us
	     */
	    s = SvPV(e->dataSV,len);
	    sv_setpvn(e->dataSV,s,len);
	    PerlIO_set_ptrcnt(n, ptr+use, (avail-use));
	    goto retry;
	}
    }
    else {
    end_of_file:
	code = -1;
	if (avail == 0)
	    PerlIOBase(f)->flags |= PERLIO_F_EOF;
	else
	    PerlIOBase(f)->flags |= PERLIO_F_ERROR;
    }
    FREETMPS;
    LEAVE;
    POPSTACK;
    return code;
}

IV
PerlIOEncode_flush(pTHX_ PerlIO * f)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    IV code = 0;

    if (e->bufsv) {
	dSP;
	SV *str;
	char *s;
	STRLEN len;
	SSize_t count = 0;
	if ((PerlIOBase(f)->flags & PERLIO_F_WRBUF) && (e->base.ptr > e->base.buf)) {
	    if (e->inEncodeCall) return 0;
	    /* Write case - encode the buffer and write() to layer below */
	    PUSHSTACKi(PERLSI_MAGIC);
	    SPAGAIN;
	    ENTER;
	    SAVETMPS;
	    PUSHMARK(sp);
	    XPUSHs(e->enc);
	    SvCUR_set(e->bufsv, e->base.ptr - e->base.buf);
	    SvUTF8_on(e->bufsv);
	    XPUSHs(e->bufsv);
	    XPUSHs(e->chk);
	    PUTBACK;
	    e->inEncodeCall = 1;
	    if (call_method("encode", G_SCALAR) != 1) {
		e->inEncodeCall = 0;
		Perl_die(aTHX_ "panic: encode did not return a value");
	    }
	    e->inEncodeCall = 0;
	    SPAGAIN;
	    str = POPs;
	    PUTBACK;
	    s = SvPV(str, len);
	    count = PerlIO_write(PerlIONext(f),s,len);
	    if ((STRLEN)count != len) {
		code = -1;
	    }
	    FREETMPS;
	    LEAVE;
	    POPSTACK;
	    if (PerlIO_flush(PerlIONext(f)) != 0) {
		code = -1;
	    }
	    if (SvCUR(e->bufsv)) {
		/* Did not all translate */
		e->base.ptr = e->base.buf+SvCUR(e->bufsv);
		return code;
	    }
	}
	else if ((PerlIOBase(f)->flags & PERLIO_F_RDBUF)) {
	    /* read case */
	    /* if we have any untranslated stuff then unread that first */
	    /* FIXME - unread is fragile is there a better way ? */
	    if (e->dataSV && SvCUR(e->dataSV)) {
		s = SvPV(e->dataSV, len);
		count = PerlIO_unread(PerlIONext(f),s,len);
		if ((STRLEN)count != len) {
		    code = -1;
		}
		SvCUR_set(e->dataSV,0);
	    }
	    /* See if there is anything left in the buffer */
	    if (e->base.ptr < e->base.end) {
		if (e->inEncodeCall) return 0;
		/* Bother - have unread data.
		   re-encode and unread() to layer below
		 */
		PUSHSTACKi(PERLSI_MAGIC);
		SPAGAIN;
		ENTER;
		SAVETMPS;
		str = sv_newmortal();
		sv_upgrade(str, SVt_PV);
		SvPV_set(str, (char*)e->base.ptr);
		SvLEN_set(str, 0);
		SvCUR_set(str, e->base.end - e->base.ptr);
		SvPOK_only(str);
		SvUTF8_on(str);
		PUSHMARK(sp);
		XPUSHs(e->enc);
		XPUSHs(str);
		XPUSHs(e->chk);
		PUTBACK;
		e->inEncodeCall = 1;
		if (call_method("encode", G_SCALAR) != 1) {
		    e->inEncodeCall = 0;
		    Perl_die(aTHX_ "panic: encode did not return a value");
		}
		e->inEncodeCall = 0;
		SPAGAIN;
		str = POPs;
		PUTBACK;
		s = SvPV(str, len);
		count = PerlIO_unread(PerlIONext(f),s,len);
		if ((STRLEN)count != len) {
		    code = -1;
		}
		FREETMPS;
		LEAVE;
		POPSTACK;
	    }
	}
	e->base.ptr = e->base.end = e->base.buf;
	PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
    }
    return code;
}

IV
PerlIOEncode_close(pTHX_ PerlIO * f)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    IV code;
    if (PerlIOBase(f)->flags & PERLIO_F_RDBUF) {
	/* Discard partial character */
	if (e->dataSV) {
	    SvCUR_set(e->dataSV,0);
	}
	/* Don't back decode and unread any pending data */
	e->base.ptr = e->base.end = e->base.buf;
    }
    code = PerlIOBase_close(aTHX_ f);
    if (e->bufsv) {
	/* This should only fire for write case */
	if (e->base.buf && e->base.ptr > e->base.buf) {
	    Perl_croak(aTHX_ "Close with partial character");
	}
	SvREFCNT_dec(e->bufsv);
	e->bufsv = Nullsv;
    }
    e->base.buf = NULL;
    e->base.ptr = NULL;
    e->base.end = NULL;
    PerlIOBase(f)->flags &= ~(PERLIO_F_RDBUF | PERLIO_F_WRBUF);
    return code;
}

Off_t
PerlIOEncode_tell(pTHX_ PerlIO * f)
{
    PerlIOBuf *b = PerlIOSelf(f, PerlIOBuf);
    /* Unfortunately the only way to get a postion is to (re-)translate,
       the UTF8 we have in bufefr and then ask layer below
     */
    PerlIO_flush(f);
    if (b->buf && b->ptr > b->buf) {
	Perl_croak(aTHX_ "Cannot tell at partial character");
    }
    return PerlIO_tell(PerlIONext(f));
}

PerlIO *
PerlIOEncode_dup(pTHX_ PerlIO * f, PerlIO * o,
		 CLONE_PARAMS * params, int flags)
{
    if ((f = PerlIOBase_dup(aTHX_ f, o, params, flags))) {
	PerlIOEncode *fe = PerlIOSelf(f, PerlIOEncode);
	PerlIOEncode *oe = PerlIOSelf(o, PerlIOEncode);
	if (oe->enc) {
	    fe->enc = PerlIO_sv_dup(aTHX_ oe->enc, params);
	}
    }
    return f;
}

SSize_t
PerlIOEncode_write(pTHX_ PerlIO *f, const void *vbuf, Size_t count)
{
    PerlIOEncode *e = PerlIOSelf(f, PerlIOEncode);
    if (e->flags & NEEDS_LINES) {
	SSize_t done = 0;
	const char *ptr = (const char *) vbuf;
	const char *end = ptr+count;
	while (ptr < end) {
	    const char *nl = ptr;
	    while (nl < end && *nl++ != '\n') /* empty body */;
	    done = PerlIOBuf_write(aTHX_ f, ptr, nl-ptr);
	    if (done != nl-ptr) {
		if (done > 0) {
		    ptr += done;
		}
		break;
	    }
	    ptr += done;
	    if (ptr[-1] == '\n') {
		if (PerlIOEncode_flush(aTHX_ f) != 0) {
		    break;
		}
	    }
	}
	return (SSize_t) (ptr - (const char *) vbuf);
    }
    else {
	return PerlIOBuf_write(aTHX_ f, vbuf, count);
    }
}

PerlIO_funcs PerlIO_encode = {
    sizeof(PerlIO_funcs),
    "encoding",
    sizeof(PerlIOEncode),
    PERLIO_K_BUFFERED|PERLIO_K_DESTRUCT,
    PerlIOEncode_pushed,
    PerlIOEncode_popped,
    PerlIOBuf_open,
    NULL, /* binmode - always pop */
    PerlIOEncode_getarg,
    PerlIOBase_fileno,
    PerlIOEncode_dup,
    PerlIOBuf_read,
    PerlIOBuf_unread,
    PerlIOEncode_write,
    PerlIOBuf_seek,
    PerlIOEncode_tell,
    PerlIOEncode_close,
    PerlIOEncode_flush,
    PerlIOEncode_fill,
    PerlIOBase_eof,
    PerlIOBase_error,
    PerlIOBase_clearerr,
    PerlIOBase_setlinebuf,
    PerlIOEncode_get_base,
    PerlIOBuf_bufsiz,
    PerlIOBuf_get_ptr,
    PerlIOBuf_get_cnt,
    PerlIOBuf_set_ptrcnt,
};
#endif				/* encode layer */

MODULE = PerlIO::encoding PACKAGE = PerlIO::encoding

PROTOTYPES: ENABLE

BOOT:
{
    SV *chk = get_sv("PerlIO::encoding::fallback", GV_ADD|GV_ADDMULTI);
    /*
     * we now "use Encode ()" here instead of
     * PerlIO/encoding.pm.  This avoids SEGV when ":encoding()"
     * is invoked without prior "use Encode". -- dankogai
     */
    PUSHSTACKi(PERLSI_MAGIC);
    SPAGAIN;
    if (!get_cv(OUR_DEFAULT_FB, 0)) {
#if 0
	/* This would just be an irritant now loading works */
	Perl_warner(aTHX_ packWARN(WARN_IO), ":encoding without 'use Encode'");
#endif
	ENTER;
	/* Encode needs a lot of stack - it is likely to move ... */
	PUTBACK;
	/* The SV is magically freed by load_module */
	load_module(PERL_LOADMOD_NOIMPORT, newSVpvn("Encode", 6), Nullsv, Nullsv);
	SPAGAIN;
	LEAVE;
    }
    PUSHMARK(sp);
    PUTBACK;
    if (call_pv(OUR_DEFAULT_FB, G_SCALAR) != 1) {
	    /* should never happen */
	    Perl_die(aTHX_ "%s did not return a value",OUR_DEFAULT_FB);
    }
    SPAGAIN;
    sv_setsv(chk, POPs);
    PUTBACK;
#ifdef PERLIO_LAYERS
    PerlIO_define_layer(aTHX_ &PerlIO_encode);
#endif
    POPSTACK;
}