Add examples

hashing/hashing_example_test.go

@@ -0,0 +1,33 @@
+package hashing_test
+
+import (
+	"bytes"
+	"crypto/md5"
+	"crypto/sha1"
+	"fmt"
+	"strings"
+
+	"github.com/fd0/khepri/hashing"
+)
+
+func ExampleReader() {
+	str := "foobar"
+	reader := hashing.NewReader(strings.NewReader(str), md5.New)
+	buf := make([]byte, len(str))
+
+	reader.Read(buf)
+
+	fmt.Printf("hash for %q is %02x", str, reader.Hash())
+	// Output: hash for "foobar" is 3858f62230ac3c915f300c664312c63f
+}
+
+func ExampleWriter() {
+	str := "foobar"
+	var buf bytes.Buffer
+
+	writer := hashing.NewWriter(&buf, sha1.New)
+	writer.Write([]byte(str))
+
+	fmt.Printf("hash for %q is %02x", str, writer.Hash())
+	// Output: hash for "foobar" is 8843d7f92416211de9ebb963ff4ce28125932878
+}