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#include "internal.h"
intptr
bio·read(io·Header *io, intptr len, void *buf)
{
uchar *b;
intptr c0, c, nr, n, ic;
b = buf;
c = len;
ic = io->ilen; // how many bytes we've read and not flushed
while(c > 0){
n = -ic;
if(n > c)
n = c;
if(n == 0){
/* only continue if we are a file reader */
if(io->state != io·BufRdr)
break;
/* get more bytes */
if(sys·read(io->fd, io->cap, io->b, &nr)){
io->state = io·BufNil;
break;
}
if(nr == 0){
io->state = io·BufEnd;
break;
}
/* shift bytes within buffer so they end at terminal */
io->g = io->b;
io->pos += nr;
if(nr < io->cap){
io->g = io->e-nr;
mem·move(io->g, io->b, nr);
}
ic -= nr;
continue;
}
/* move our read bytes into the caller's buffer */
mem·move(b, io->e+ic, n);
c -= n;
ic += n;
b += n;
}
io->ilen = ic;
if(c == len && io->state == io·BufNil)
return -1;
return len-c;
}
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