Import sources from 2011-03-30 iso image

1 files changed, 115 insertions, 0 deletions

diff --git a/sys/src/cmd/cdfs/buf.c b/sys/src/cmd/cdfs/buf.c
new file mode 100755
index 000000000..245cdf325
--- /dev/null
+++ b/sys/src/cmd/cdfs/buf.c
@@ -0,0 +1,115 @@
+/*
+ * Buffered I/O on block devices.
+ * Write buffering ignores offset.
+ */
+
+#include <u.h>
+#include <libc.h>
+#include <disk.h>
+#include "dat.h"
+#include "fns.h"
+
+Buf*
+bopen(long (*fn)(Buf*, void*, long, ulong), int omode, int bs, int nblock)
+{
+	Buf *b;
+
+	assert(omode == OREAD || OWRITE);
+	assert(bs > 0 && nblock > 0);
+	assert(fn != nil);
+
+	b = emalloc(sizeof(*b));
+	b->data = emalloc(bs*nblock);
+	b->ndata = 0;
+	b->nblock = nblock;
+	b->bs = bs;
+	b->omode = omode;
+	b->fn = fn;		/* function to read or write bs-byte blocks */
+
+	return b;
+}
+
+long
+bread(Buf *b, void *v, long n, vlong off)
+{
+	long m;
+	vlong noff;
+
+	assert(b->omode == OREAD);
+
+	/* Refill buffer */
+	if(b->off > off || off >= b->off+b->ndata) {
+		noff = off - off % b->bs;
+		if(vflag)
+			fprint(2, "try refill at %lld...", noff);
+		if((m = b->fn(b, b->data, b->nblock, noff/b->bs)) <= 0) {
+			if (vflag)
+				fprint(2, "failed\n");
+			return m;
+		}
+		b->ndata = b->bs * m;
+		b->off = noff;
+		if(vflag)
+			fprint(2, "got %ld\n", b->ndata);
+	}
+
+//	fprint(2, "read %ld at %ld\n", n, off);
+	/* Satisfy request from buffer */
+	off -= b->off;
+	if(n > b->ndata - off)
+		n = b->ndata - off;
+	memmove(v, b->data+off, n);
+	return n;
+}
+
+long
+bwrite(Buf *b, void *v, long n)
+{
+	long on, m, mdata;
+	uchar *p;
+
+	p = v;
+	on = n;
+
+	/* Fill buffer */
+	mdata = b->bs*b->nblock;
+	m = mdata - b->ndata;
+	if(m > n)
+		m = n;
+	memmove(b->data+b->ndata, p, m);
+	p += m;
+	n -= m;
+	b->ndata += m;
+
+	/* Flush buffer */
+	if(b->ndata == mdata) {
+		if(b->fn(b, b->data, b->nblock, 0) < 0) {
+			if(vflag)
+				fprint(2, "write fails: %r\n");
+			return -1;
+		}
+		b->ndata = 0;
+	}
+
+	/* For now, don't worry about big writes; 9P only does 8k */
+	assert(n < mdata);
+
+	/* Add remainder to buffer */
+	if(n) {
+		memmove(b->data, p, n);
+		b->ndata = n;
+	}
+
+	return on;
+}
+
+void
+bterm(Buf *b)
+{
+	/* DVD & BD prefer full ecc blocks (tracks), but can cope with less */
+	if(b->omode == OWRITE && b->ndata)
+		b->fn(b, b->data, (b->ndata + b->bs - 1)/b->bs, 0); 
+
+	free(b->data);
+	free(b);
+}