source: mainline/uspace/lib/posix/src/stdio/scanf.c@ 1b20da0

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 1b20da0 was 1b20da0, checked in by Jiří Zárevúcky <zarevucky.jiri@…>, 7 years ago

style: Remove trailing whitespace on non-empty lines, in certain file types.

Command used: tools/srepl '\([^[:space:]]\)\s\+$' '\1' -- *.c *.h *.py *.sh *.s *.S *.ag
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File size: 32.8 KB
Line 
1/*
2 * Copyright (c) 2011 Petr Koupy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup libposix
30 * @{
31 */
32/** @file Implementation of the scanf backend.
33 */
34
35#include <assert.h>
36
37#include <errno.h>
38
39#include "posix/stdio.h"
40#include "posix/stdlib.h"
41#include "posix/stddef.h"
42#include "posix/string.h"
43#include "posix/ctype.h"
44#include "posix/sys/types.h"
45
46#include "../internal/common.h"
47#include "libc/malloc.h"
48#include "libc/stdbool.h"
49
50/** Unified data type for possible data sources for scanf. */
51typedef union __data_source {
52 FILE *stream; /**< Input file stream. */
53 const char *string; /**< Input string. */
54} _data_source;
55
56/** Internal state of the input provider. */
57enum {
58 /** Partly constructed but not yet functional. */
59 _PROV_CONSTRUCTED,
60 /** Ready to serve any request. */
61 _PROV_READY,
62 /** Cursor is temporarily lent to the external entity. No action is
63 * possible until the cursor is returned. */
64 _PROV_CURSOR_LENT,
65};
66
67/** Universal abstraction over data input for scanf. */
68typedef struct __input_provider {
69 /** Source of data elements. */
70 _data_source source;
71 /** How many elements was already processed. */
72 int consumed;
73 /** How many elements was already fetched from the source. */
74 int fetched;
75 /** Elements are fetched from the source in batches (e.g. by getline())
76 * to allow using strtol/strtod family even on streams. */
77 char *window;
78 /** Size of the current window. */
79 size_t window_size;
80 /** Points to the next element to be processed inside the current window. */
81 const char *cursor;
82 /** Internal state of the provider. */
83 int state;
84
85 /** Take control over data source. Finish initialization of the internal
86 * structures (e.g. allocation of window). */
87 void (*capture)(struct __input_provider *);
88 /** Get a single element from the source and update the internal structures
89 * accordingly (e.g. greedy update of the window). Return -1 if the
90 * element cannot be obtained. */
91 int (*pop)(struct __input_provider *);
92 /** Undo the most recent not-undone pop operation. Might be necesarry to
93 * flush current window and seek data source backwards. Return 0 if the
94 * pop history is exhausted, non-zero on success. */
95 int (*undo)(struct __input_provider *);
96 /** Lend the cursor to the caller. */
97 const char * (*borrow_cursor)(struct __input_provider *);
98 /** Take control over possibly incremented cursor and update the internal
99 * structures if necessary. */
100 void (*return_cursor)(struct __input_provider *, const char *);
101 /** Release the control over the source. That is, synchronize any
102 * fetched but non-consumed elements (e.g. by seeking) and destruct
103 * internal structures (e.g. window deallocation). */
104 void (*release)(struct __input_provider *);
105} _input_provider;
106
107/** @see __input_provider */
108static void _capture_stream(_input_provider *self)
109{
110 assert(self->source.stream);
111 assert(self->state == _PROV_CONSTRUCTED);
112 /* Caller could already pre-allocated the window. */
113 assert((self->window == NULL && self->window_size == 0) ||
114 (self->window && self->window_size > 0));
115
116 /* Initialize internal structures. */
117 self->consumed = 0;
118 ssize_t fetched = getline(
119 &self->window, &self->window_size, self->source.stream);
120 if (fetched != -1) {
121 self->fetched = fetched;
122 self->cursor = self->window;
123 } else {
124 /* EOF encountered. */
125 self->fetched = 0;
126 self->cursor = NULL;
127 }
128 self->state = _PROV_READY;
129}
130
131/** @see __input_provider */
132static void _capture_string(_input_provider *self)
133{
134 assert(self->source.string);
135 assert(self->state == _PROV_CONSTRUCTED);
136
137 /* Initialize internal structures. */
138 self->consumed = 0;
139 self->fetched = strlen(self->source.string);
140 self->window = (char *) self->source.string;
141 self->window_size = self->fetched + 1;
142 self->cursor = self->window;
143 self->state = _PROV_READY;
144}
145
146/** @see __input_provider */
147static int _pop_stream(_input_provider *self)
148{
149 assert(self->state == _PROV_READY);
150
151 if (self->cursor) {
152 int c = *self->cursor;
153 ++self->consumed;
154 ++self->cursor;
155 /* Do we need to fetch a new line from the source? */
156 if (*self->cursor == '\0') {
157 ssize_t fetched = getline(&self->window,
158 &self->window_size, self->source.stream);
159 if (fetched != -1) {
160 self->fetched += fetched;
161 self->cursor = self->window;
162 } else {
163 /* EOF encountered. */
164 self->cursor = NULL;
165 }
166 }
167 return c;
168 } else {
169 /* Already at EOF. */
170 return -1;
171 }
172}
173
174/** @see __input_provider */
175static int _pop_string(_input_provider *self)
176{
177 assert(self->state == _PROV_READY);
178
179 if (*self->cursor != '\0') {
180 int c = *self->cursor;
181 ++self->consumed;
182 ++self->cursor;
183 return c;
184 } else {
185 /* String depleted. */
186 return -1;
187 }
188}
189
190/** @see __input_provider */
191static int _undo_stream(_input_provider *self)
192{
193 assert(self->state == _PROV_READY);
194
195 if (self->consumed == 0) {
196 /* Undo history exhausted. */
197 return 0;
198 }
199
200 if (!self->cursor || self->window == self->cursor) {
201 /* Complex case. Either at EOF (cursor == NULL) or there is no more
202 * place to retreat to inside the window. Seek the source backwards
203 * and flush the window. Regarding the scanf, this could happend only
204 * when matching unbounded string (%s) or unbounded scanset (%[) not
205 * containing newline, while at the same time newline is the character
206 * that breaks the matching process. */
207 int rc = fseek(self->source.stream, -1, SEEK_CUR);
208 if (rc == -1) {
209 /* Seek failed. */
210 return 0;
211 }
212 ssize_t fetched = getline(&self->window,
213 &self->window_size, self->source.stream);
214 if (fetched != -1) {
215 assert(fetched == 1);
216 self->fetched = self->consumed + 1;
217 self->cursor = self->window;
218 } else {
219 /* Stream is broken. */
220 return 0;
221 }
222 } else {
223 /* Simple case. Still inside window. */
224 --self->cursor;
225 }
226 --self->consumed;
227 return 1; /* Success. */
228}
229
230/** @see __input_provider */
231static int _undo_string(_input_provider *self)
232{
233 assert(self->state == _PROV_READY);
234
235 if (self->consumed > 0) {
236 --self->consumed;
237 --self->cursor;
238 } else {
239 /* Undo history exhausted. */
240 return 0;
241 }
242 return 1; /* Success. */
243}
244
245/** @see __input_provider */
246static const char *_borrow_cursor_universal(_input_provider *self)
247{
248 assert(self->state == _PROV_READY);
249
250 self->state = _PROV_CURSOR_LENT;
251 return self->cursor;
252}
253
254/** @see __input_provider */
255static void _return_cursor_stream(_input_provider *self, const char *cursor)
256{
257 assert(self->state == _PROV_CURSOR_LENT);
258
259 /* Check how much of the window did external entity consumed. */
260 self->consumed += cursor - self->cursor;
261 self->cursor = cursor;
262 if (*self->cursor == '\0') {
263 /* Window was completely consumed, fetch new data. */
264 ssize_t fetched = getline(&self->window,
265 &self->window_size, self->source.stream);
266 if (fetched != -1) {
267 self->fetched += fetched;
268 self->cursor = self->window;
269 } else {
270 /* EOF encountered. */
271 self->cursor = NULL;
272 }
273 }
274 self->state = _PROV_READY;
275}
276
277/** @see __input_provider */
278static void _return_cursor_string(_input_provider *self, const char *cursor)
279{
280 assert(self->state == _PROV_CURSOR_LENT);
281
282 /* Check how much of the window did external entity consumed. */
283 self->consumed += cursor - self->cursor;
284 self->cursor = cursor;
285 self->state = _PROV_READY;
286}
287
288/** @see __input_provider */
289static void _release_stream(_input_provider *self)
290{
291 assert(self->state == _PROV_READY);
292 assert(self->consumed >= self->fetched);
293
294 /* Try to correct the difference between the stream position and what was
295 * actually consumed. If it is not possible, continue anyway. */
296 fseek(self->source.stream, self->consumed - self->fetched, SEEK_CUR);
297
298 /* Destruct internal structures. */
299 self->fetched = 0;
300 self->cursor = NULL;
301 if (self->window) {
302 free(self->window);
303 self->window = NULL;
304 }
305 self->window_size = 0;
306 self->state = _PROV_CONSTRUCTED;
307}
308
309/** @see __input_provider */
310static void _release_string(_input_provider *self)
311{
312 assert(self->state == _PROV_READY);
313
314 /* Destruct internal structures. */
315 self->fetched = 0;
316 self->cursor = NULL;
317 self->window = NULL;
318 self->window_size = 0;
319 self->state = _PROV_CONSTRUCTED;
320}
321
322/** Length modifier values. */
323enum {
324 LMOD_NONE,
325 LMOD_hh,
326 LMOD_h,
327 LMOD_l,
328 LMOD_ll,
329 LMOD_j,
330 LMOD_z,
331 LMOD_t,
332 LMOD_L,
333 LMOD_p, /* Reserved for %p conversion. */
334};
335
336/**
337 * Decides whether provided characters specify length modifier. If so, the
338 * recognized modifier is stored through provider pointer.
339 *
340 * @param c Candidate on the length modifier.
341 * @param _c Next character (might be NUL).
342 * @param modifier Pointer to the modifier value.
343 * @return Whether the modifier was recognized or not.
344 */
345static inline int is_length_mod(int c, int _c, int *modifier)
346{
347 assert(modifier);
348
349 switch (c) {
350 case 'h':
351 /* Check whether the modifier was not already recognized. */
352 if (*modifier == LMOD_NONE) {
353 *modifier = _c == 'h' ? LMOD_hh : LMOD_h;
354 } else {
355 /* Format string is invalid. Notify the caller. */
356 *modifier = LMOD_NONE;
357 }
358 return 1;
359 case 'l':
360 if (*modifier == LMOD_NONE) {
361 *modifier = _c == 'l' ? LMOD_ll : LMOD_l;
362 } else {
363 *modifier = LMOD_NONE;
364 }
365 return 1;
366 case 'j':
367 *modifier = *modifier == LMOD_NONE ? LMOD_j : LMOD_NONE;
368 return 1;
369 case 'z':
370 *modifier = *modifier == LMOD_NONE ? LMOD_z : LMOD_NONE;
371 return 1;
372 case 't':
373 *modifier = *modifier == LMOD_NONE ? LMOD_t : LMOD_NONE;
374 return 1;
375 case 'L':
376 *modifier = *modifier == LMOD_NONE ? LMOD_L : LMOD_NONE;
377 return 1;
378 default:
379 return 0;
380 }
381}
382
383/**
384 * Decides whether provided character specifies integer conversion. If so, the
385 * semantics of the conversion is stored through provided pointers..
386 *
387 * @param c Candidate on the integer conversion.
388 * @param is_unsigned Pointer to store whether the conversion is signed or not.
389 * @param base Pointer to store the base of the integer conversion.
390 * @return Whether the conversion was recognized or not.
391 */
392static inline int is_int_conv(int c, bool *is_unsigned, int *base)
393{
394 assert(is_unsigned && base);
395
396 switch (c) {
397 case 'd':
398 *is_unsigned = false;
399 *base = 10;
400 return 1;
401 case 'i':
402 *is_unsigned = false;
403 *base = 0;
404 return 1;
405 case 'o':
406 *is_unsigned = true;
407 *base = 8;
408 return 1;
409 case 'u':
410 *is_unsigned = true;
411 *base = 10;
412 return 1;
413 case 'p': /* According to POSIX, %p modifier is implementation defined but
414 * must correspond to its printf counterpart. */
415 case 'x':
416 case 'X':
417 *is_unsigned = true;
418 *base = 16;
419 return 1;
420 return 1;
421 default:
422 return 0;
423 }
424}
425
426/**
427 * Decides whether provided character specifies conversion of the floating
428 * point number.
429 *
430 * @param c Candidate on the floating point conversion.
431 * @return Whether the conversion was recognized or not.
432 */
433static inline int is_float_conv(int c)
434{
435 switch (c) {
436 case 'a':
437 case 'A':
438 case 'e':
439 case 'E':
440 case 'f':
441 case 'F':
442 case 'g':
443 case 'G':
444 return 1;
445 default:
446 return 0;
447 }
448}
449
450/**
451 * Decides whether provided character specifies conversion of the character
452 * sequence.
453 *
454 * @param c Candidate on the character sequence conversion.
455 * @param modifier Pointer to store length modifier for wide chars.
456 * @return Whether the conversion was recognized or not.
457 */
458static inline int is_seq_conv(int c, int *modifier)
459{
460 assert(modifier);
461
462 switch (c) {
463 case 'S':
464 *modifier = LMOD_l;
465 /* Fallthrough */
466 case 's':
467 return 1;
468 case 'C':
469 *modifier = LMOD_l;
470 /* Fallthrough */
471 case 'c':
472 return 1;
473 case '[':
474 return 1;
475 default:
476 return 0;
477 }
478}
479
480/**
481 * Backend for the whole family of scanf functions. Uses input provider
482 * to abstract over differences between strings and streams. Should be
483 * POSIX compliant (apart from the not supported stuff).
484 *
485 * NOT SUPPORTED: locale (see strtold), wide chars, numbered output arguments
486 *
487 * @param in Input provider.
488 * @param fmt Format description.
489 * @param arg Output arguments.
490 * @return The number of converted output items or EOF on failure.
491 */
492static inline int _internal_scanf(
493 _input_provider *in, const char *restrict fmt, va_list arg)
494{
495 int c = -1;
496 int converted_cnt = 0;
497 bool converting = false;
498 bool matching_failure = false;
499
500 bool assign_supress = false;
501 bool assign_alloc = false;
502 long width = -1;
503 int length_mod = LMOD_NONE;
504 bool int_conv_unsigned = false;
505 int int_conv_base = 0;
506
507 /* Buffers allocated by scanf for optional 'm' specifier must be remembered
508 * to deallocaate them in case of an error. Because each of those buffers
509 * corresponds to one of the argument from va_list, there is an upper bound
510 * on the number of those arguments. In case of C99, this uppper bound is
511 * 127 arguments. */
512 char *buffers[127];
513 for (int i = 0; i < 127; ++i) {
514 buffers[i] = NULL;
515 }
516 int next_unused_buffer_idx = 0;
517
518 in->capture(in);
519
520 /* Interpret format string. Control shall prematurely jump from the cycle
521 * on input failure, matching failure or illegal format string. In order
522 * to keep error reporting simple enough and to keep input consistent,
523 * error condition shall be always manifested as jump from the cycle,
524 * not function return. Format string pointer shall be updated specifically
525 * for each sub-case (i.e. there shall be no loop-wide increment).*/
526 while (*fmt) {
527
528 if (converting) {
529
530 /* Processing inside conversion specifier. Either collect optional
531 * parameters or execute the conversion. When the conversion
532 * is successfully completed, increment conversion count and switch
533 * back to normal mode. */
534 if (*fmt == '*') {
535 /* Assignment-supression (optional). */
536 if (assign_supress) {
537 /* Already set. Illegal format string. */
538 break;
539 }
540 assign_supress = true;
541 ++fmt;
542 } else if (*fmt == 'm') {
543 /* Assignment-allocation (optional). */
544 if (assign_alloc) {
545 /* Already set. Illegal format string. */
546 break;
547 }
548 assign_alloc = true;
549 ++fmt;
550 } else if (*fmt == '$') {
551 /* Reference to numbered output argument. */
552 // TODO
553 not_implemented();
554 } else if (isdigit(*fmt)) {
555 /* Maximum field length (optional). */
556 if (width != -1) {
557 /* Already set. Illegal format string. */
558 break;
559 }
560 char *fmt_new = NULL;
561 width = strtol(fmt, &fmt_new, 10);
562 if (width != 0) {
563 fmt = fmt_new;
564 } else {
565 /* Since POSIX requires width to be non-zero, it is
566 * sufficient to interpret zero width as error without
567 * referring to errno. */
568 break;
569 }
570 } else if (is_length_mod(*fmt, *(fmt + 1), &length_mod)) {
571 /* Length modifier (optional). */
572 if (length_mod == LMOD_NONE) {
573 /* Already set. Illegal format string. The actual detection
574 * is carried out in the is_length_mod(). */
575 break;
576 }
577 if (length_mod == LMOD_hh || length_mod == LMOD_ll) {
578 /* Modifier was two characters long. */
579 ++fmt;
580 }
581 ++fmt;
582 } else if (is_int_conv(*fmt, &int_conv_unsigned, &int_conv_base)) {
583 /* Integer conversion. */
584
585 /* Check sanity of optional parts of conversion specifier. */
586 if (assign_alloc || length_mod == LMOD_L) {
587 /* Illegal format string. */
588 break;
589 }
590
591 /* Conversion of the integer with %p specifier needs special
592 * handling, because it is not allowed to have arbitrary
593 * length modifier. */
594 if (*fmt == 'p') {
595 if (length_mod == LMOD_NONE) {
596 length_mod = LMOD_p;
597 } else {
598 /* Already set. Illegal format string. */
599 break;
600 }
601 }
602
603 /* First consume any white spaces, so we can borrow cursor
604 * from the input provider. This way, the cursor will either
605 * point to the non-white space while the input will be
606 * prefetched up to the newline (which is suitable for strtol),
607 * or the input will be at EOF. */
608 do {
609 c = in->pop(in);
610 } while (isspace(c));
611
612 /* After skipping the white spaces, can we actually continue? */
613 if (c == -1) {
614 /* Input failure. */
615 break;
616 } else {
617 /* Everything is OK, just undo the last pop, so the cursor
618 * can be borrowed. */
619 in->undo(in);
620 }
621
622 const char *cur_borrowed = NULL;
623 char *cur_duplicated = NULL;
624 const char *cur_limited = NULL;
625 const char *cur_updated = NULL;
626
627 /* Borrow the cursor. Until it is returned to the provider
628 * we cannot jump from the cycle, because it would leave
629 * the input inconsistent. */
630 cur_borrowed = in->borrow_cursor(in);
631
632 /* If the width is limited, the cursor horizont must be
633 * decreased accordingly. Otherwise the strtol could read more
634 * than allowed by width. */
635 if (width != -1) {
636 cur_duplicated = strndup(cur_borrowed, width);
637 cur_limited = cur_duplicated;
638 } else {
639 cur_limited = cur_borrowed;
640 }
641 cur_updated = cur_limited;
642
643 long long sres = 0;
644 unsigned long long ures = 0;
645 errno = 0; /* Reset errno to recognize error later. */
646 /* Try to convert the integer. */
647 if (int_conv_unsigned) {
648 ures = strtoull(cur_limited, (char **) &cur_updated, int_conv_base);
649 } else {
650 sres = strtoll(cur_limited, (char **) &cur_updated, int_conv_base);
651 }
652
653 /* Update the cursor so it can be returned to the provider. */
654 cur_borrowed += cur_updated - cur_limited;
655 if (cur_duplicated != NULL) {
656 /* Deallocate duplicated part of the cursor view. */
657 free(cur_duplicated);
658 }
659 cur_limited = NULL;
660 cur_updated = NULL;
661 cur_duplicated = NULL;
662 /* Return the cursor to the provider. Input consistency is again
663 * the job of the provider, so we can report errors from
664 * now on. */
665 in->return_cursor(in, cur_borrowed);
666 cur_borrowed = NULL;
667
668 /* Check whether the conversion was successful. */
669 if (errno != EOK) {
670 matching_failure = true;
671 break;
672 }
673
674 /* If not supressed, assign the converted integer into
675 * the next output argument. */
676 if (!assign_supress) {
677 if (int_conv_unsigned) {
678 switch (length_mod) {
679 case LMOD_hh: ; /* Label cannot be part of declaration. */
680 unsigned char *phh = va_arg(arg, unsigned char *);
681 *phh = (unsigned char) ures;
682 break;
683 case LMOD_h: ;
684 unsigned short *ph = va_arg(arg, unsigned short *);
685 *ph = (unsigned short) ures;
686 break;
687 case LMOD_NONE: ;
688 unsigned *pdef = va_arg(arg, unsigned *);
689 *pdef = (unsigned) ures;
690 break;
691 case LMOD_l: ;
692 unsigned long *pl = va_arg(arg, unsigned long *);
693 *pl = (unsigned long) ures;
694 break;
695 case LMOD_ll: ;
696 unsigned long long *pll = va_arg(arg, unsigned long long *);
697 *pll = (unsigned long long) ures;
698 break;
699 case LMOD_j: ;
700 uintmax_t *pj = va_arg(arg, uintmax_t *);
701 *pj = (uintmax_t) ures;
702 break;
703 case LMOD_z: ;
704 size_t *pz = va_arg(arg, size_t *);
705 *pz = (size_t) ures;
706 break;
707 case LMOD_t: ;
708 // XXX: What is unsigned counterpart of the ptrdiff_t?
709 size_t *pt = va_arg(arg, size_t *);
710 *pt = (size_t) ures;
711 break;
712 case LMOD_p: ;
713 void **pp = va_arg(arg, void **);
714 *pp = (void *) (uintptr_t) ures;
715 break;
716 default:
717 assert(false);
718 }
719 } else {
720 switch (length_mod) {
721 case LMOD_hh: ; /* Label cannot be part of declaration. */
722 signed char *phh = va_arg(arg, signed char *);
723 *phh = (signed char) sres;
724 break;
725 case LMOD_h: ;
726 short *ph = va_arg(arg, short *);
727 *ph = (short) sres;
728 break;
729 case LMOD_NONE: ;
730 int *pdef = va_arg(arg, int *);
731 *pdef = (int) sres;
732 break;
733 case LMOD_l: ;
734 long *pl = va_arg(arg, long *);
735 *pl = (long) sres;
736 break;
737 case LMOD_ll: ;
738 long long *pll = va_arg(arg, long long *);
739 *pll = (long long) sres;
740 break;
741 case LMOD_j: ;
742 intmax_t *pj = va_arg(arg, intmax_t *);
743 *pj = (intmax_t) sres;
744 break;
745 case LMOD_z: ;
746 ssize_t *pz = va_arg(arg, ssize_t *);
747 *pz = (ssize_t) sres;
748 break;
749 case LMOD_t: ;
750 ptrdiff_t *pt = va_arg(arg, ptrdiff_t *);
751 *pt = (ptrdiff_t) sres;
752 break;
753 default:
754 assert(false);
755 }
756 }
757 ++converted_cnt;
758 }
759
760 converting = false;
761 ++fmt;
762 } else if (is_float_conv(*fmt)) {
763 /* Floating point number conversion. */
764
765 /* Check sanity of optional parts of conversion specifier. */
766 if (assign_alloc) {
767 /* Illegal format string. */
768 break;
769 }
770 if (length_mod != LMOD_NONE &&
771 length_mod != LMOD_l &&
772 length_mod != LMOD_L) {
773 /* Illegal format string. */
774 break;
775 }
776
777 /* First consume any white spaces, so we can borrow cursor
778 * from the input provider. This way, the cursor will either
779 * point to the non-white space while the input will be
780 * prefetched up to the newline (which is suitable for strtof),
781 * or the input will be at EOF. */
782 do {
783 c = in->pop(in);
784 } while (isspace(c));
785
786 /* After skipping the white spaces, can we actually continue? */
787 if (c == -1) {
788 /* Input failure. */
789 break;
790 } else {
791 /* Everything is OK, just undo the last pop, so the cursor
792 * can be borrowed. */
793 in->undo(in);
794 }
795
796 const char *cur_borrowed = NULL;
797 const char *cur_limited = NULL;
798 char *cur_duplicated = NULL;
799 const char *cur_updated = NULL;
800
801 /* Borrow the cursor. Until it is returned to the provider
802 * we cannot jump from the cycle, because it would leave
803 * the input inconsistent. */
804 cur_borrowed = in->borrow_cursor(in);
805
806 /* If the width is limited, the cursor horizont must be
807 * decreased accordingly. Otherwise the strtof could read more
808 * than allowed by width. */
809 if (width != -1) {
810 cur_duplicated = strndup(cur_borrowed, width);
811 cur_limited = cur_duplicated;
812 } else {
813 cur_limited = cur_borrowed;
814 }
815 cur_updated = cur_limited;
816
817 float fres = 0.0;
818 double dres = 0.0;
819 long double ldres = 0.0;
820 errno = 0; /* Reset errno to recognize error later. */
821 /* Try to convert the floating point nubmer. */
822 switch (length_mod) {
823 case LMOD_NONE:
824 fres = strtof(cur_limited, (char **) &cur_updated);
825 break;
826 case LMOD_l:
827 dres = strtod(cur_limited, (char **) &cur_updated);
828 break;
829 case LMOD_L:
830 ldres = strtold(cur_limited, (char **) &cur_updated);
831 break;
832 default:
833 assert(false);
834 }
835
836 /* Update the cursor so it can be returned to the provider. */
837 cur_borrowed += cur_updated - cur_limited;
838 if (cur_duplicated != NULL) {
839 /* Deallocate duplicated part of the cursor view. */
840 free(cur_duplicated);
841 }
842 cur_limited = NULL;
843 cur_updated = NULL;
844 /* Return the cursor to the provider. Input consistency is again
845 * the job of the provider, so we can report errors from
846 * now on. */
847 in->return_cursor(in, cur_borrowed);
848 cur_borrowed = NULL;
849
850 /* Check whether the conversion was successful. */
851 if (errno != EOK) {
852 matching_failure = true;
853 break;
854 }
855
856 /* If nto supressed, assign the converted floating point number
857 * into the next output argument. */
858 if (!assign_supress) {
859 switch (length_mod) {
860 case LMOD_NONE: ; /* Label cannot be part of declaration. */
861 float *pf = va_arg(arg, float *);
862 *pf = fres;
863 break;
864 case LMOD_l: ;
865 double *pd = va_arg(arg, double *);
866 *pd = dres;
867 break;
868 case LMOD_L: ;
869 long double *pld = va_arg(arg, long double *);
870 *pld = ldres;
871 break;
872 default:
873 assert(false);
874 }
875 ++converted_cnt;
876 }
877
878 converting = false;
879 ++fmt;
880 } else if (is_seq_conv(*fmt, &length_mod)) {
881 /* Character sequence conversion. */
882
883 /* Check sanity of optional parts of conversion specifier. */
884 if (length_mod != LMOD_NONE &&
885 length_mod != LMOD_l) {
886 /* Illegal format string. */
887 break;
888 }
889
890 if (length_mod == LMOD_l) {
891 /* Wide chars not supported. */
892 // TODO
893 not_implemented();
894 }
895
896 int term_size = 1; /* Size of the terminator (0 or 1)). */
897 if (*fmt == 'c') {
898 term_size = 0;
899 width = width == -1 ? 1 : width;
900 }
901
902 if (*fmt == 's') {
903 /* Skip white spaces. */
904 do {
905 c = in->pop(in);
906 } while (isspace(c));
907 } else {
908 /* Fetch a single character. */
909 c = in->pop(in);
910 }
911
912 /* Check whether there is still input to read. */
913 if (c == -1) {
914 /* Input failure. */
915 break;
916 }
917
918 /* Prepare scanset. */
919 char terminate_on[256];
920 for (int i = 0; i < 256; ++i) {
921 terminate_on[i] = 0;
922 }
923 if (*fmt == 'c') {
924 ++fmt;
925 } else if (*fmt == 's') {
926 terminate_on[' '] = 1;
927 terminate_on['\n'] = 1;
928 terminate_on['\t'] = 1;
929 terminate_on['\f'] = 1;
930 terminate_on['\r'] = 1;
931 terminate_on['\v'] = 1;
932 ++fmt;
933 } else {
934 assert(*fmt == '[');
935 bool not = false;
936 bool dash = false;
937 ++fmt;
938 /* Check for negation. */
939 if (*fmt == '^') {
940 not = true;
941 ++fmt;
942 }
943 /* Check for escape sequences. */
944 if (*fmt == '-' || *fmt == ']') {
945 terminate_on[(int) *fmt] = 1;
946 ++fmt;
947 }
948 /* Check for ordinary characters and ranges. */
949 while (*fmt != '\0' && *fmt != ']') {
950 if (dash) {
951 for (char chr = *(fmt - 2); chr <= *fmt; ++chr) {
952 terminate_on[(int) chr] = 1;
953 }
954 dash = false;
955 } else if (*fmt == '-') {
956 dash = true;
957 } else {
958 terminate_on[(int) *fmt] = 1;
959 }
960 ++fmt;
961 }
962 /* Check for escape sequence. */
963 if (dash == true) {
964 terminate_on['-'] = 1;
965 }
966 /* Check whether the specifier was correctly terminated.*/
967 if (*fmt == '\0') {
968 /* Illegal format string. */
969 break;
970 } else {
971 ++fmt;
972 }
973 /* Inverse the scanset if necessary. */
974 if (not == false) {
975 for (int i = 0; i < 256; ++i) {
976 terminate_on[i] = terminate_on[i] ? 0 : 1;
977 }
978 }
979 }
980
981 char * buf = NULL;
982 size_t buf_size = 0;
983 char * cur = NULL;
984 size_t alloc_step = 80; /* Buffer size gain during reallocation. */
985 int my_buffer_idx = 0;
986
987 /* Retrieve the buffer into which popped characters
988 * will be stored. */
989 if (!assign_supress) {
990 if (assign_alloc) {
991 /* We must allocate our own buffer. */
992 buf_size =
993 width == -1 ? alloc_step : (size_t) width + term_size;
994 buf = malloc(buf_size);
995 if (!buf) {
996 /* No memory. */
997 break;
998 }
999 my_buffer_idx = next_unused_buffer_idx;
1000 ++next_unused_buffer_idx;
1001 buffers[my_buffer_idx] = buf;
1002 cur = buf;
1003 } else {
1004 /* Caller provided its buffer. */
1005 buf = va_arg(arg, char *);
1006 cur = buf;
1007 buf_size =
1008 width == -1 ? SIZE_MAX : (size_t) width + term_size;
1009 }
1010 }
1011
1012 /* Match the string. The next character is already popped. */
1013 while ((width == -1 || width > 0) && c != -1 && !terminate_on[c]) {
1014
1015 /* Check whether the buffer is still sufficiently large. */
1016 if (!assign_supress) {
1017 /* Always reserve space for the null terminator. */
1018 if (cur == buf + buf_size - term_size) {
1019 /* Buffer size must be increased. */
1020 buf = realloc(buf, buf_size + alloc_step);
1021 if (buf) {
1022 buffers[my_buffer_idx] = buf;
1023 cur = buf + buf_size - term_size;
1024 buf_size += alloc_step;
1025 } else {
1026 /* Break just from this tight loop. Errno will
1027 * be checked after it. */
1028 break;
1029 }
1030 }
1031 /* Store the input character. */
1032 *cur = c;
1033 }
1034
1035 width = width == -1 ? -1 : width - 1;
1036 ++cur;
1037 c = in->pop(in);
1038 }
1039 if (errno == ENOMEM) {
1040 /* No memory. */
1041 break;
1042 }
1043 if (c != -1) {
1044 /* There is still more input, so undo the last pop. */
1045 in->undo(in);
1046 }
1047
1048 /* Check for failures. */
1049 if (cur == buf) {
1050 /* Matching failure. Input failure was already checked
1051 * earlier. */
1052 matching_failure = true;
1053 if (!assign_supress && assign_alloc) {
1054 /* Roll back. */
1055 free(buf);
1056 buffers[my_buffer_idx] = NULL;
1057 --next_unused_buffer_idx;
1058 }
1059 break;
1060 }
1061
1062 /* Store the terminator. */
1063 if (!assign_supress && term_size > 0) {
1064 /* Space for the terminator was reserved. */
1065 *cur = '\0';
1066 }
1067
1068 /* Store the result if not already stored. */
1069 if (!assign_supress) {
1070 if (assign_alloc) {
1071 char **pbuf = va_arg(arg, char **);
1072 *pbuf = buf;
1073 }
1074 ++converted_cnt;
1075 }
1076
1077 converting = false;
1078 /* Format string pointer already incremented. */
1079 } else if (*fmt == 'n') {
1080 /* Report the number of consumed bytes so far. */
1081
1082 /* Sanity check. */
1083 bool sane =
1084 width == -1 &&
1085 length_mod == LMOD_NONE &&
1086 assign_alloc == false &&
1087 assign_supress == false;
1088
1089 if (sane) {
1090 int *pi = va_arg(arg, int *);
1091 *pi = in->consumed;
1092 } else {
1093 /* Illegal format string. */
1094 break;
1095 }
1096
1097 /* This shall not be counted as conversion. */
1098 converting = false;
1099 ++fmt;
1100 } else {
1101 /* Illegal format string. */
1102 break;
1103 }
1104
1105 } else {
1106
1107 /* Processing outside conversion specifier. Either skip white
1108 * spaces or match characters one by one. If conversion specifier
1109 * is detected, switch to coversion mode. */
1110 if (isspace(*fmt)) {
1111 /* Skip white spaces in the format string. */
1112 while (isspace(*fmt)) {
1113 ++fmt;
1114 }
1115 /* Skip white spaces in the input. */
1116 do {
1117 c = in->pop(in);
1118 } while (isspace(c));
1119 if (c != -1) {
1120 /* Input is not at EOF, so undo the last pop operation. */
1121 in->undo(in);
1122 }
1123 } else if (*fmt == '%' && *(fmt + 1) != '%') {
1124 /* Conversion specifier detected. Switch modes. */
1125 converting = true;
1126 /* Reset the conversion context. */
1127 assign_supress = false;
1128 assign_alloc = false;
1129 width = -1;
1130 length_mod = LMOD_NONE;
1131 int_conv_unsigned = false;
1132 int_conv_base = 0;
1133 ++fmt;
1134 } else {
1135 /* One by one matching. */
1136 if (*fmt == '%') {
1137 /* Escape sequence detected. */
1138 ++fmt;
1139 assert(*fmt == '%');
1140 }
1141 c = in->pop(in);
1142 if (c == -1) {
1143 /* Input failure. */
1144 break;
1145 } else if (c != *fmt) {
1146 /* Matching failure. */
1147 in->undo(in);
1148 matching_failure = true;
1149 break;
1150 } else {
1151 ++fmt;
1152 }
1153 }
1154
1155 }
1156
1157 }
1158
1159 in->release(in);
1160
1161 /* This somewhat complicated return value decision is required by POSIX. */
1162 int rc;
1163 if (matching_failure) {
1164 rc = converted_cnt;
1165 } else {
1166 if (errno == EOK) {
1167 rc = converted_cnt > 0 ? converted_cnt : EOF;
1168 } else {
1169 rc = EOF;
1170 }
1171 }
1172 if (rc == EOF) {
1173 /* Caller will not know how many arguments were successfully converted,
1174 * so the deallocation of buffers is our responsibility. */
1175 for (int i = 0; i < next_unused_buffer_idx; ++i) {
1176 free(buffers[i]);
1177 buffers[i] = NULL;
1178 }
1179 next_unused_buffer_idx = 0;
1180 }
1181 return rc;
1182}
1183
1184/**
1185 * Convert formatted input from the stream.
1186 *
1187 * @param stream Input stream.
1188 * @param format Format description.
1189 * @param arg Output items.
1190 * @return The number of converted output items or EOF on failure.
1191 */
1192int vfscanf(
1193 FILE *restrict stream, const char *restrict format, va_list arg)
1194{
1195 _input_provider provider = {
1196 { 0 }, 0, 0, NULL, 0, NULL, _PROV_CONSTRUCTED,
1197 _capture_stream, _pop_stream, _undo_stream,
1198 _borrow_cursor_universal, _return_cursor_stream, _release_stream
1199 };
1200 provider.source.stream = stream;
1201 return _internal_scanf(&provider, format, arg);
1202}
1203
1204/**
1205 * Convert formatted input from the string.
1206 *
1207 * @param s Input string.
1208 * @param format Format description.
1209 * @param arg Output items.
1210 * @return The number of converted output items or EOF on failure.
1211 */
1212int vsscanf(
1213 const char *restrict s, const char *restrict format, va_list arg)
1214{
1215 _input_provider provider = {
1216 { 0 }, 0, 0, NULL, 0, NULL, _PROV_CONSTRUCTED,
1217 _capture_string, _pop_string, _undo_string,
1218 _borrow_cursor_universal, _return_cursor_string, _release_string
1219 };
1220 provider.source.string = s;
1221 return _internal_scanf(&provider, format, arg);
1222}
1223
1224/** @}
1225 */
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