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app/admin/main/member/model/bom/BUILD

@@ -0,0 +1,42 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+    "go_test",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "bom.go",
+        "discard_go15.go",
+    ],
+    importpath = "go-common/app/admin/main/member/model/bom",
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)
+
+go_test(
+    name = "go_default_xtest",
+    srcs = ["bom_test.go"],
+    tags = ["automanaged"],
+    deps = [
+        "//app/admin/main/member/model/bom:go_default_library",
+        "//vendor/github.com/stretchr/testify/assert:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

app/admin/main/member/model/bom/bom.go

@@ -0,0 +1,39 @@
+// Package bom is used to clean up UTF-8 Byte Order Marks.
+package bom
+
+import (
+	"bufio"
+	"io"
+)
+
+const (
+	bom0 = 0xef
+	bom1 = 0xbb
+	bom2 = 0xbf
+)
+
+// Clean returns b with the 3 byte BOM stripped off the front if it is present.
+// If the BOM is not present, then b is returned.
+func Clean(b []byte) []byte {
+	if len(b) >= 3 &&
+		b[0] == bom0 &&
+		b[1] == bom1 &&
+		b[2] == bom2 {
+		return b[3:]
+	}
+	return b
+}
+
+// NewReader returns an io.Reader that will skip over initial UTF-8 byte order marks.
+func NewReader(r io.Reader) io.Reader {
+	buf := bufio.NewReader(r)
+	b, err := buf.Peek(3)
+	if err != nil {
+		// not enough bytes
+		return buf
+	}
+	if b[0] == bom0 && b[1] == bom1 && b[2] == bom2 {
+		discardBytes(buf, 3)
+	}
+	return buf
+}

app/admin/main/member/model/bom/bom_test.go

@@ -0,0 +1,80 @@
+package bom_test
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+
+	"go-common/app/admin/main/member/model/bom"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var testCases = []struct {
+	Input    []byte
+	Expected []byte
+}{
+	{
+		Input:    nil,
+		Expected: nil,
+	},
+	{
+		Input:    []byte{},
+		Expected: []byte{},
+	},
+	{
+		Input:    []byte{0xef},
+		Expected: []byte{0xef},
+	},
+	{
+		Input:    []byte{0xef, 0xbb},
+		Expected: []byte{0xef, 0xbb},
+	},
+	{
+		Input:    []byte{0xef, 0xbb, 0xbf},
+		Expected: []byte{},
+	},
+	{
+		Input:    []byte{0xef, 0xbb, 0xbf, 0x41, 0x42, 0x43},
+		Expected: []byte{0x41, 0x42, 0x43},
+	},
+	{
+		Input:    []byte{0xef, 0xbb, 0x41, 0x42, 0x43},
+		Expected: []byte{0xef, 0xbb, 0x41, 0x42, 0x43},
+	},
+	{
+		Input:    []byte{0xef, 0x41, 0x42, 0x43},
+		Expected: []byte{0xef, 0x41, 0x42, 0x43},
+	},
+	{
+		Input:    []byte{0x41, 0x42, 0x43},
+		Expected: []byte{0x41, 0x42, 0x43},
+	},
+}
+
+func TestClean(t *testing.T) {
+	assert := assert.New(t)
+
+	for _, tc := range testCases {
+		output := bom.Clean(tc.Input)
+		assert.Equal(tc.Expected, output)
+	}
+}
+
+func TestReader(t *testing.T) {
+	assert := assert.New(t)
+
+	for _, tc := range testCases {
+		// An input value of nil works differently to the Clean function.
+		// In this case it results in an empty buffer, not nil.
+		expected := tc.Expected
+		if tc.Input == nil {
+			expected = []byte{}
+		}
+		r1 := bytes.NewReader(tc.Input)
+		r2 := bom.NewReader(r1)
+		output, err := ioutil.ReadAll(r2)
+		assert.NoError(err)
+		assert.Equal(expected, output)
+	}
+}

app/admin/main/member/model/bom/discard_go14.go

@@ -0,0 +1,12 @@
+// +build !go1.5
+
+package bom
+
+import "bufio"
+
+func discardBytes(buf *bufio.Reader, n int) {
+	// cannot use the buf.Discard method as it was introduced in Go 1.5
+	for i := 0; i < n; i++ {
+		buf.ReadByte()
+	}
+}

app/admin/main/member/model/bom/discard_go15.go

@@ -0,0 +1,10 @@
+// +build go1.5
+
+package bom
+
+import "bufio"
+
+func discardBytes(buf *bufio.Reader, n int) {
+	// the Discard method was introduced in Go 1.5
+	buf.Discard(n)
+}