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#include "lib9.h"
#include <bio.h>
#include <fmt.h>
#include <sys/types.h>
#include <unistd.h>
off_t
Bseek(Biobuf *bp, off_t offset, int base)
{
long long n, d;
int bufsz;
switch(bp->state) {
default:
fprint(2, "Bseek: unknown state %d\n", bp->state);
return Beof;
case Bracteof:
bp->state = Bractive;
bp->icount = 0;
bp->gbuf = bp->ebuf;
case Bractive:
n = offset;
if(base == 1) {
n += Boffset(bp);
base = 0;
}
/*
* try to seek within buffer
*/
if(base == 0) {
d = n - Boffset(bp);
bufsz = bp->ebuf - bp->gbuf;
if(-bufsz <= d && d <= bufsz){
bp->icount += d;
if(d >= 0) {
if(bp->icount <= 0)
return n;
} else {
if(bp->ebuf - bp->gbuf >= -bp->icount)
return n;
}
}
}
/*
* reset the buffer
*/
n = lseek(bp->fid, n, base);
bp->icount = 0;
bp->gbuf = bp->ebuf;
break;
case Bwactive:
Bflush(bp);
n = lseek(bp->fid, offset, base);
break;
}
bp->offset = n;
return n;
}
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