string to bytes value formatter

Author: jeevatkm

format.go

@@ -0,0 +1,57 @@
+// Copyright (c) Jeevanandam M. (https://github.com/jeevatkm)
+// go-aah/essentials source code and usage is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package ess
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// Byte unit value
+const (
+	ByteSize     = 1.0
+	KiloByteSize = 1024 * ByteSize
+	MegaByteSize = 1024 * KiloByteSize
+	GigaByteSize = 1024 * MegaByteSize
+	TeraByteSize = 1024 * GigaByteSize
+)
+
+var sizePattern = regexp.MustCompile(`(?i)^(\d+)([kmgt]?[i]?[b?|b])$`)
+
+// StrToBytes method returns bytes value for given string value.
+//    For e.g.:
+//      2mb ==> 2097152 bytes
+//      2MB ==> 2097152 bytes
+//      2MiB ==> 2097152 bytes
+func StrToBytes(value string) (int64, error) {
+	segments := sizePattern.FindStringSubmatch(strings.TrimSpace(value))
+	if len(segments) < 3 {
+		return 0, fmt.Errorf("format: invalid input '%s'", value)
+	}
+
+	unitValue, err := strconv.ParseInt(segments[1], 10, 0)
+	if err != nil {
+		return 0, fmt.Errorf("format: unable to parse '%d'", unitValue)
+	}
+
+	var bytes int64
+	unit := strings.ToLower(segments[2])
+	switch unit[:1] {
+	case "t":
+		bytes = unitValue * TeraByteSize
+	case "g":
+		bytes = unitValue * GigaByteSize
+	case "m":
+		bytes = unitValue * MegaByteSize
+	case "k":
+		bytes = unitValue * KiloByteSize
+	case "b":
+		bytes = unitValue * ByteSize
+	}
+
+	return bytes, nil
+}

format_test.go

@@ -0,0 +1,59 @@
+// Copyright (c) Jeevanandam M. (https://github.com/jeevatkm)
+// go-aah/essentials source code and usage is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package ess
+
+import (
+	"testing"
+
+	"aahframework.org/test/assert"
+)
+
+func TestBStrToBytes(t *testing.T) {
+	checkBytesValue(t, "2b", int64(2))
+	checkBytesValue(t, "2B", int64(2))
+	checkBytesValue(t, "2b", int64(2))
+	checkBytesValue(t, "2B", int64(2))
+}
+
+func TestKBStrToBytes(t *testing.T) {
+	checkBytesValue(t, "2kb", int64(2048))
+	checkBytesValue(t, "2KB", int64(2048))
+	checkBytesValue(t, "2kib", int64(2048))
+	checkBytesValue(t, "2KiB", int64(2048))
+}
+
+func TestMBStrToBytes(t *testing.T) {
+	checkBytesValue(t, "2mb", int64(2097152))
+	checkBytesValue(t, "2MB", int64(2097152))
+	checkBytesValue(t, "2mib", int64(2097152))
+	checkBytesValue(t, "2MiB", int64(2097152))
+}
+
+func TestGBStrToBytes(t *testing.T) {
+	checkBytesValue(t, "2gb", int64(2147483648))
+	checkBytesValue(t, "2GB", int64(2147483648))
+	checkBytesValue(t, "2Gib", int64(2147483648))
+	checkBytesValue(t, "2GiB", int64(2147483648))
+}
+
+func TestTBStrToBytes(t *testing.T) {
+	checkBytesValue(t, "2tb", int64(2199023255552))
+	checkBytesValue(t, "2TB", int64(2199023255552))
+	checkBytesValue(t, "2Tib", int64(2199023255552))
+	checkBytesValue(t, "2TiB", int64(2199023255552))
+}
+
+func TestErrStrToBytes(t *testing.T) {
+	v1, err := StrToBytes("2")
+	assert.NotNil(t, err)
+	assert.Equal(t, "format: invalid input '2'", err.Error())
+	assert.Equal(t, int64(0), v1)
+}
+
+func checkBytesValue(t *testing.T, value string, expt int64) {
+	v, err := StrToBytes(value)
+	assert.Nil(t, err)
+	assert.Equal(t, expt, v)
+}