20060303a

1 files changed, 122 insertions, 0 deletions

diff --git a/appl/lib/diskblocks.b b/appl/lib/diskblocks.b
new file mode 100644
index 00000000..a98505e7
--- /dev/null
+++ b/appl/lib/diskblocks.b
@@ -0,0 +1,122 @@
+implement Diskblocks;
+
+#
+# adapted from Acme's disk.b
+#
+
+include "sys.m";
+	sys: Sys;
+
+include "diskblocks.m";
+
+init()
+{
+	sys = load Sys Sys->PATH;
+}
+
+tempfile(): ref Sys->FD
+{
+	user := "inferno";
+	fd := sys->open("/dev/user", Sys->OREAD);
+	if(fd != nil){
+		b := array[Sys->NAMEMAX] of byte;
+		n := sys->read(fd, b, len b);
+		if(n > 0)
+			user = string b[0:n];
+	}
+	fd = nil;
+	buf := sys->sprint("/tmp/X%d.%.4sblks", sys->pctl(0, nil), user);
+	for(i:='A'; i<='Z'; i++){
+		buf[5] = i;
+		if(sys->stat(buf).t0 == 0)
+			continue;
+		fd = sys->create(buf, Sys->ORDWR|Sys->ORCLOSE|Sys->OEXCL, 8r600);
+		if(fd != nil)
+			return fd;
+	}
+	return nil;
+}
+
+Disk.init(fd: ref Sys->FD, gran: int, maxblock: int): ref Disk
+{
+	d := ref Disk;
+	if(gran == 0 || maxblock%gran != 0)
+		return nil;
+	d.maxblock = maxblock;
+	d.gran = gran;
+	d.free = array[maxblock/gran+1] of list of ref Block;
+	d.addr = big 0;
+	d.fd = fd;
+	d.lock = chan[1] of int;
+	return d;
+}
+
+ntosize(d: ref Disk, n: int): (int, int)
+{
+	if (n > d.maxblock)
+		return (-1, -1);
+	size := n;
+	if((size % d.gran) != 0)
+		size += d.gran - size%d.gran;
+	# last bucket holds blocks of exactly d.maxblock
+	return (size, size/d.gran);
+}
+
+Disk.new(d: self ref Disk, n: int): ref Block
+{
+	(size, i) := ntosize(d, n);
+	if(i < 0){
+		sys->werrstr("illegal Disk allocation");
+		return nil;
+	}
+	b: ref Block;
+	d.lock <-= 1;
+	if(d.free[i] != nil){
+		b = hd d.free[i];
+		d.free[i] = tl d.free[i];
+	}else{
+		b = ref Block(d.addr, 0);
+		d.addr += big size;
+	}
+	<-d.lock;
+	b.n = n;
+	return b;
+}
+
+Disk.release(d: self ref Disk, b: ref Block)
+{
+	(nil, i) := ntosize(d, b.n);
+	d.lock <-= 1;
+	d.free[i] = b :: d.free[i];
+	<-d.lock;
+}
+
+Disk.write(d: self ref Disk, b: ref Block, a: array of byte, n: int): ref Block
+{
+	if(b != nil){
+		(size, nil) := ntosize(d, b.n);
+		(nsize, nil) := ntosize(d, n);
+		if(size != nsize){
+			d.release(b);
+			b = d.new(n);
+		}
+	}else
+		b = d.new(n);
+	if(b == nil)
+		return nil;
+	if(sys->pwrite(d.fd, a, n, b.addr) != n){
+		sys->werrstr(sys->sprint("Disk write error: %r"));
+		return nil;
+	}
+	b.n = n;
+	return b;
+}
+
+Disk.read(d: self ref Disk, b: ref Block, a: array of byte, n: int): int
+{
+	if(b == nil || n > b.n){
+		sys->werrstr("read request bigger than block");
+		return -1;
+	}
+	return sys->pread(d.fd, a, n, b.addr);
+}