lib/bytes: add function AppendInt64 and AppendUint64

The AppendInt64 append an int64 value into slice of byte.
The AppendUint64 append an uint64 value into slice of byte.

2 files changed, 86 insertions, 6 deletions

diff --git a/lib/bytes/bytes.go b/lib/bytes/bytes.go
index 6e44f0a6..b47b0a85 100644
--- a/lib/bytes/bytes.go
+++ b/lib/bytes/bytes.go
@@ -1,6 +1,6 @@
-// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// SPDX-FileCopyrightText: 2018 M. Shulhan <ms@kilabit.info>
+//
+// SPDX-License-Identifier: BSD-3-Clause
 
 // Package bytes provide a library for working with byte or slice of bytes.
 package bytes
@@ -32,6 +32,19 @@ func AppendInt32(data []byte, v int32) []byte {
 	return data
 }
 
+// AppendInt64 append an int64 value into slice of byte.
+func AppendInt64(data []byte, v int64) []byte {
+	data = append(data, byte(v>>56))
+	data = append(data, byte(v>>48))
+	data = append(data, byte(v>>40))
+	data = append(data, byte(v>>32))
+	data = append(data, byte(v>>24))
+	data = append(data, byte(v>>16))
+	data = append(data, byte(v>>8))
+	data = append(data, byte(v))
+	return data
+}
+
 // AppendUint16 append an uint16 value into slice of byte.
 func AppendUint16(data []byte, v uint16) []byte {
 	data = append(data, byte(v>>8))
@@ -48,6 +61,19 @@ func AppendUint32(data []byte, v uint32) []byte {
 	return data
 }
 
+// AppendUint64 append an uint64 value into slice of byte.
+func AppendUint64(data []byte, v uint64) []byte {
+	data = append(data, byte(v>>56))
+	data = append(data, byte(v>>48))
+	data = append(data, byte(v>>40))
+	data = append(data, byte(v>>32))
+	data = append(data, byte(v>>24))
+	data = append(data, byte(v>>16))
+	data = append(data, byte(v>>8))
+	data = append(data, byte(v))
+	return data
+}
+
 // Concat merge one or more []byte or string in args into slice of
 // byte.
 // Any type that is not []byte or string in args will be ignored.
diff --git a/lib/bytes/bytes_example_test.go b/lib/bytes/bytes_example_test.go
index d1efbafe..0c2fbf49 100644
--- a/lib/bytes/bytes_example_test.go
+++ b/lib/bytes/bytes_example_test.go
@@ -1,6 +1,6 @@
-// Copyright 2018, Shulhan <ms@kilabit.info>. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// SPDX-FileCopyrightText: 2018 M. Shulhan <ms@kilabit.info>
+//
+// SPDX-License-Identifier: BSD-3-Clause
 
 package bytes_test
 
@@ -38,6 +38,33 @@ func ExampleAppendInt32() {
 	//  2147483647 => 0x7fffffff => []byte{0x7f, 0xff, 0xff, 0xff}
 }
 
+func ExampleAppendInt64() {
+	var listInt64 = []int64{
+		math.MaxInt64,
+		1000,
+		math.MinInt64,
+	}
+
+	var (
+		v   int64
+		out []byte
+	)
+	for _, v = range listInt64 {
+		out = libbytes.AppendInt64(nil, v)
+		fmt.Printf("%d\n=> %#x\n=> %#v\n", v, v, out)
+	}
+	// Output:
+	// 9223372036854775807
+	// => 0x7fffffffffffffff
+	// => []byte{0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
+	// 1000
+	// => 0x3e8
+	// => []byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x3, 0xe8}
+	// -9223372036854775808
+	// => -0x8000000000000000
+	// => []byte{0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}
+}
+
 func ExampleAppendUint16() {
 	inputs := []uint16{0, 0xab, 0xabc, math.MaxInt16, math.MaxUint16}
 	for _, v := range inputs {
@@ -78,6 +105,33 @@ func ExampleAppendUint32() {
 	//           1 => 0x1 => []byte{0x0, 0x0, 0x0, 0x1}
 }
 
+func ExampleAppendUint64() {
+	var listUint64 = []uint64{
+		math.MaxUint64,
+		math.MaxInt64,
+		1000,
+	}
+
+	var (
+		v   uint64
+		out []byte
+	)
+	for _, v = range listUint64 {
+		out = libbytes.AppendUint64(nil, v)
+		fmt.Printf("%d\n=> %#x\n=> %#v\n", v, v, out)
+	}
+	// Output:
+	// 18446744073709551615
+	// => 0xffffffffffffffff
+	// => []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
+	// 9223372036854775807
+	// => 0x7fffffffffffffff
+	// => []byte{0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
+	// 1000
+	// => 0x3e8
+	// => []byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x3, 0xe8}
+}
+
 func ExampleConcat() {
 	fmt.Printf("%s\n", libbytes.Concat())
 	fmt.Printf("%s\n", libbytes.Concat([]byte{}))