xref: /aosp_15_r20/external/musl/src/stdio/ungetwc.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include "stdio_impl.h"
2*c9945492SAndroid Build Coastguard Worker #include "locale_impl.h"
3*c9945492SAndroid Build Coastguard Worker #include <wchar.h>
4*c9945492SAndroid Build Coastguard Worker #include <limits.h>
5*c9945492SAndroid Build Coastguard Worker #include <ctype.h>
6*c9945492SAndroid Build Coastguard Worker #include <string.h>
7*c9945492SAndroid Build Coastguard Worker 
ungetwc(wint_t c,FILE * f)8*c9945492SAndroid Build Coastguard Worker wint_t ungetwc(wint_t c, FILE *f)
9*c9945492SAndroid Build Coastguard Worker {
10*c9945492SAndroid Build Coastguard Worker 	unsigned char mbc[MB_LEN_MAX];
11*c9945492SAndroid Build Coastguard Worker 	int l;
12*c9945492SAndroid Build Coastguard Worker 	locale_t *ploc = &CURRENT_LOCALE, loc = *ploc;
13*c9945492SAndroid Build Coastguard Worker 
14*c9945492SAndroid Build Coastguard Worker 	FLOCK(f);
15*c9945492SAndroid Build Coastguard Worker 
16*c9945492SAndroid Build Coastguard Worker 	if (f->mode <= 0) fwide(f, 1);
17*c9945492SAndroid Build Coastguard Worker 	*ploc = f->locale;
18*c9945492SAndroid Build Coastguard Worker 
19*c9945492SAndroid Build Coastguard Worker 	if (!f->rpos) __toread(f);
20*c9945492SAndroid Build Coastguard Worker 	if (!f->rpos || c == WEOF || (l = wcrtomb((void *)mbc, c, 0)) < 0 ||
21*c9945492SAndroid Build Coastguard Worker 	    f->rpos < f->buf - UNGET + l) {
22*c9945492SAndroid Build Coastguard Worker 		FUNLOCK(f);
23*c9945492SAndroid Build Coastguard Worker 		*ploc = loc;
24*c9945492SAndroid Build Coastguard Worker 		return WEOF;
25*c9945492SAndroid Build Coastguard Worker 	}
26*c9945492SAndroid Build Coastguard Worker 
27*c9945492SAndroid Build Coastguard Worker 	if (isascii(c)) *--f->rpos = c;
28*c9945492SAndroid Build Coastguard Worker 	else memcpy(f->rpos -= l, mbc, l);
29*c9945492SAndroid Build Coastguard Worker 
30*c9945492SAndroid Build Coastguard Worker 	f->flags &= ~F_EOF;
31*c9945492SAndroid Build Coastguard Worker 
32*c9945492SAndroid Build Coastguard Worker 	FUNLOCK(f);
33*c9945492SAndroid Build Coastguard Worker 	*ploc = loc;
34*c9945492SAndroid Build Coastguard Worker 	return c;
35*c9945492SAndroid Build Coastguard Worker }
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