added a few more useful readers

trash.go

@@ -7,25 +7,43 @@ import (
 )
 
 func init() {
-	Reader = &reader{}
+	Reader = &reader{0xca}
+	Zeros = &reader{0x00}
+	Fs = &reader{0xff}
+	HiLo = &reader{0xaa}
+	LoHi = &reader{0x55}
 }
 
 // Reader provides a steady stream of trash (non-random bytes) when read from
 var Reader io.Reader
 
+// Zeros provides a steady stream of 0x00
+var Zeros io.Reader
+
+// Fs provides a steady stream of 0xff
+var Fs io.Reader
+
+// HiLo provides a steady stream of 0xaa
+var HiLo io.Reader
+
+// LoHi provides a steady stream of 0x55
+var LoHi io.Reader
+
 // TimeoutReader returns a reader that returns io.EOF after dur.
 func TimeoutReader(dur time.Duration) io.Reader {
 	return &timeoutReader{timeout: time.Now().Add(dur)}
 }
 
-type reader struct{}
+type reader struct {
+	pattern byte
+}
 
 func (r *reader) Read(p []byte) (int, error) {
 	c := 0
 	var err error
 	for i := 0; i < len(p); i++ {
 		c++
-		p[i] = 0xca
+		p[i] = r.pattern
 	}
 	return c, err
 }