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#include "lib9.h"
#include <bio.h>
int
Bgetc(Biobuf *bp)
{
int i;
loop:
i = bp->icount;
if(i != 0) {
bp->icount = i+1;
return bp->ebuf[i];
}
if(bp->state != Bractive) {
if(bp->state == Bracteof)
bp->state = Bractive;
return Beof;
}
/*
* get next buffer, try to keep Bungetsize
* characters pre-catenated from the previous
* buffer to allow that many ungets.
*/
memmove(bp->bbuf-Bungetsize, bp->ebuf-Bungetsize, Bungetsize);
i = read(bp->fid, bp->bbuf, bp->bsize);
bp->gbuf = bp->bbuf;
if(i <= 0) {
bp->state = Bracteof;
if(i < 0)
bp->state = Binactive;
return Beof;
}
if(i < bp->bsize) {
memmove(bp->ebuf-i-Bungetsize, bp->bbuf-Bungetsize, i+Bungetsize);
bp->gbuf = bp->ebuf-i;
}
bp->icount = -i;
bp->offset += i;
goto loop;
}
int
Bungetc(Biobuf *bp)
{
if(bp->state == Bracteof)
bp->state = Bractive;
if(bp->state != Bractive)
return Beof;
bp->icount--;
return 1;
}
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