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#include "shgetc.h"
/* The shcnt field stores the number of bytes read so far, offset by
* the value of buf-rpos at the last function call (__shlim or __shgetc),
* so that between calls the inline shcnt macro can add rpos-buf to get
* the actual count. */
void __shlim(FILE *f, off_t lim)
{
f->shlim = lim;
f->shcnt = f->buf - f->rpos;
/* If lim is nonzero, rend must be a valid pointer. */
if (lim && f->rend - f->rpos > lim)
f->shend = f->rpos + lim;
else
f->shend = f->rend;
}
int __shgetc(FILE *f)
{
int c;
off_t cnt = shcnt(f);
if (f->shlim && cnt >= f->shlim || (c=__uflow(f)) < 0) {
f->shcnt = f->buf - f->rpos + cnt;
f->shend = f->rpos;
f->shlim = -1;
return EOF;
}
cnt++;
if (f->shlim && f->rend - f->rpos > f->shlim - cnt)
f->shend = f->rpos + (f->shlim - cnt);
else
f->shend = f->rend;
f->shcnt = f->buf - f->rpos + cnt;
if (f->rpos <= f->buf) f->rpos[-1] = c;
return c;
}
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