Kernel/src/io.c

71  *	buf          ptr        buf+cnt   buf+size
85  *	buf             ptr       buf+cnt buf+size
93  *	buf             ptr       buf+cnt buf+size
96  *	When writing, ptr may go beyond buf+cnt.
121  *	buf             ptr    buf+cnt    buf+size
124  *	Buf+cnt indicates the end of the used buffer and is always >= ptr.
125  *	If the buffer is the last in the chain, Buf+cnt is the end of "file".
131  *  StreamCnt	every buffer in the list has its own cnt field, which is
145  *	buf          ptr        buf+cnt   buf+size
147  *	Ptr is used for reading only, writing is done at buf+cnt.
150  *   this buffer is StreamWBuf + BufHeader(StreamWBuf)->cnt.
161  *  StreamCnt	every buffer in the list has its own cnt field, which is copied
307 	StreamCnt(nst) = StreamBufHeader(nst)->cnt; \
312 	StreamCnt(nst) = StreamBufHeader(nst)->cnt; \
318 	buf_header->cnt = 0; \
375     uword			cnt;
1460 	count += BufHeader(buf)->cnt - (ptr - buf);
1462 	while(ptr < buf + BufHeader(buf)->cnt)
1479 	    BufHeader(StreamWBuf(nst))->cnt - (StreamPtr(nst)-StreamBuf(nst));
1482 	    (StreamSize(nst)-(StreamPtr(nst)-StreamBuf(nst))) + BufHeader(StreamWBuf(nst))->cnt;
1496 	count += BufHeader(buf)->cnt;
1516 	count += BufHeader(buf)->cnt;
1517 	for (ptr = buf; ptr < buf + BufHeader(buf)->cnt; )
1573     wptr = wbuf + BufHeader(wbuf)->cnt;
1574     bfree = StreamSize(nst) - BufHeader(wbuf)->cnt;
1583 	BufHeader(wbuf)->cnt = wptr - wbuf;
1585 	    StreamCnt(nst) = BufHeader(wbuf)->cnt;
1587 	    StreamOffset(nst) += BufHeader(wbuf)->cnt;
1605     for(i = BufHeader(wbuf)->cnt; i < BufHeader(wbuf)->cnt + count; ++i)
1607     BufHeader(wbuf)->cnt += count;
1609 	StreamCnt(nst) = BufHeader(wbuf)->cnt;
1611     wbuf[BufHeader(wbuf)->cnt] = EOB_MARK;
1633 	    StreamCnt(nst) = StreamBufHeader(nst)->cnt = StreamPtr(nst) - StreamBuf(nst);
1652 	StreamCnt(nst) = StreamBufHeader(nst)->cnt = StreamPtr(nst) - StreamBuf(nst);
2036 	    StreamCnt(nst) = BufHeader(StreamBuf(nst))->cnt = pos - StreamOffset(nst);
2049 	    StreamCnt(nst) = BufHeader(StreamBuf(nst))->cnt = StreamSize(nst);
2062 		StreamCnt(nst) = BufHeader(StreamBuf(nst))->cnt = StreamSize(nst);
2069 	    StreamCnt(nst) = BufHeader(StreamBuf(nst))->cnt = pos - StreamOffset(nst);
2342     StreamCnt(nst) = StreamBufHeader(nst)->cnt = StreamPtr(nst) - StreamBuf(nst);
3021     int		cnt = 0;
3025 	cnt = write(fd, buf, n);
3026 	if (cnt == n)
3028 	else if (cnt < 0 )
3039 	    n -= cnt;
3040 	    buf += cnt;