mirror of
https://github.com/fluencelabs/musl
synced 2025-06-09 13:01:34 +00:00
34 lines
608 B
C
34 lines
608 B
C
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#include "stdio_impl.h"
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int ungetc(int c, FILE *f)
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{
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if (c == EOF) return c;
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FLOCK(f);
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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->wbase = 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 already full, fail. */
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if (f->rpos <= f->buf - UNGET) {
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FUNLOCK(f);
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return EOF;
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}
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/* Put a byte back into the buffer */
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*--f->rpos = c;
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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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