mirror of
https://github.com/fluencelabs/musl
synced 2025-05-21 19:51:31 +00:00
46 lines
865 B
C
46 lines
865 B
C
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#include "stdio_impl.h"
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wint_t ungetwc(wint_t c, FILE *f)
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{
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unsigned char mbc[MB_LEN_MAX];
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int l=1;
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if (c == WEOF) return c;
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/* Try conversion early so we can fail without locking if invalid */
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if (!isascii(c) && (l = wctomb(mbc, c)) < 0)
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return WEOF;
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FLOCK(f);
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f->mode |= f->mode+1;
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/* Fail if unreadable or writing and unable to flush */
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if ((f->flags & (F_ERR|F_NORD)) || (f->wpos && __oflow(f))) {
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FUNLOCK(f);
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return EOF;
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}
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/* Clear write mode */
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f->wpos = f->wstop = f->wend = 0;
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/* Put the file in read mode */
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if (!f->rpos) f->rpos = f->rend = f->buf;
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/* If unget buffer is nonempty, fail. */
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if (f->rpos < f->buf) {
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FUNLOCK(f);
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return WEOF;
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}
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/* Put character back into the buffer */
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if (isascii(c)) *--f->rpos = c;
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else memcpy(f->rpos -= l, mbc, l);
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/* Clear EOF */
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f->flags &= ~F_EOF;
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FUNLOCK(f);
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return c;
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}
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