From ad5b4b52e88991a581ef6217d4500be24dd9e220 Mon Sep 17 00:00:00 2001
From: Harshavardhana <harsha@harshavardhana.net>
Date: Sun, 30 Nov 2014 22:56:33 -0800
Subject: [PATCH] strbyteconv -    - StringToBytes()    - BytesToString()

---
 pkgs/strbyteconv/strbyteconv.go      | 93 ++++++++++++++++++++++++++++
 pkgs/strbyteconv/strbyteconv_test.go | 62 +++++++++++++++++++
 2 files changed, 155 insertions(+)
 create mode 100644 pkgs/strbyteconv/strbyteconv.go
 create mode 100644 pkgs/strbyteconv/strbyteconv_test.go

diff --git a/pkgs/strbyteconv/strbyteconv.go b/pkgs/strbyteconv/strbyteconv.go
new file mode 100644
index 000000000..64a12a76d
--- /dev/null
+++ b/pkgs/strbyteconv/strbyteconv.go
@@ -0,0 +1,93 @@
+/*
+ * Mini Object Storage, (C) 2014 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package strbyteconv
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+const (
+	UNIT_BYTE     = 1
+	UNIT_KILOBYTE = 1024 * UNIT_BYTE
+	UNIT_MEGABYTE = 1024 * UNIT_KILOBYTE
+	UNIT_GIGABYTE = 1024 * UNIT_MEGABYTE
+	UNIT_TERABYTE = 1024 * UNIT_GIGABYTE
+)
+
+func BytesToString(bytes uint64) string {
+	var unit string = "B"
+	var value uint64 = 0
+
+	switch {
+	case bytes >= UNIT_TERABYTE:
+		unit = "TB"
+		value = uint64(bytes / UNIT_TERABYTE)
+	case bytes >= UNIT_GIGABYTE:
+		unit = "GB"
+		value = uint64(bytes / UNIT_GIGABYTE)
+	case bytes >= UNIT_MEGABYTE:
+		unit = "MB"
+		value = uint64(bytes / UNIT_MEGABYTE)
+	case bytes >= UNIT_KILOBYTE:
+		unit = "KB"
+		value = uint64(bytes / UNIT_KILOBYTE)
+	case bytes < UNIT_KILOBYTE && bytes >= UNIT_BYTE:
+		unit = "B"
+		value = uint64(bytes / UNIT_BYTE)
+	}
+
+	return fmt.Sprintf("%d%s", value, unit)
+}
+
+func StringToBytes(s string) (uint64, error) {
+	var bytes uint64
+
+	StringPattern, err := regexp.Compile(`(?i)^(-?\d+)([KMGT])B?$`)
+	if err != nil {
+		return 0, err
+	}
+
+	parts := StringPattern.FindStringSubmatch(strings.TrimSpace(s))
+	if len(parts) < 3 {
+		return 0, errors.New("Incorrect string format must be K,KB,M,MB,G,GB")
+	}
+
+	value, err := strconv.ParseUint(parts[1], 10, 0)
+	if err != nil || value < 1 {
+		return 0, err
+	}
+
+	unit := strings.ToUpper(parts[2])
+	switch unit {
+	case "T":
+		bytes = value * UNIT_TERABYTE
+	case "G":
+		bytes = value * UNIT_GIGABYTE
+	case "M":
+		bytes = value * UNIT_MEGABYTE
+	case "K":
+		bytes = value * UNIT_KILOBYTE
+	case "B":
+		bytes = value * UNIT_BYTE
+	}
+
+	return bytes, nil
+}
diff --git a/pkgs/strbyteconv/strbyteconv_test.go b/pkgs/strbyteconv/strbyteconv_test.go
new file mode 100644
index 000000000..2f807ff50
--- /dev/null
+++ b/pkgs/strbyteconv/strbyteconv_test.go
@@ -0,0 +1,62 @@
+/*
+ * Mini Object Storage, (C) 2014 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package strbyteconv
+
+import (
+	. "gopkg.in/check.v1"
+	"testing"
+)
+
+type MySuite struct{}
+
+var _ = Suite(&MySuite{})
+
+func Test(t *testing.T) { TestingT(t) }
+
+func (s *MySuite) Test(c *C) {
+	value := BytesToString(100 * UNIT_BYTE)
+	c.Assert(value, Equals, "100B")
+
+	value = BytesToString(100 * UNIT_KILOBYTE)
+	c.Assert(value, Equals, "100KB")
+
+	value = BytesToString(100 * UNIT_MEGABYTE)
+	c.Assert(value, Equals, "100MB")
+
+	value = BytesToString(100 * UNIT_GIGABYTE)
+	c.Assert(value, Equals, "100GB")
+
+	value = BytesToString(100 * UNIT_TERABYTE)
+	c.Assert(value, Equals, "100TB")
+
+	bytes, err := StringToBytes("100KB")
+	c.Assert(err, IsNil)
+	c.Assert(bytes, Equals, uint64(100*UNIT_KILOBYTE))
+
+	bytes, err = StringToBytes("100MB")
+	c.Assert(err, IsNil)
+	c.Assert(bytes, Equals, uint64(100*UNIT_MEGABYTE))
+
+	bytes, err = StringToBytes("100GB")
+	c.Assert(err, IsNil)
+	c.Assert(bytes, Equals, uint64(100*UNIT_GIGABYTE))
+
+	bytes, err = StringToBytes("100TB")
+	c.Assert(err, IsNil)
+	c.Assert(bytes, Equals, uint64(100*UNIT_TERABYTE))
+
+}