added WriteReadVarSize test, added PutVarSize/GetVarSize and test

little/little.go

@@ -32,6 +32,7 @@ var (
 	ErrNoSpace      = errors.New("bin: no space")
 	ErrTooLong      = errors.New("bin: too long") // слишком длинная строка или массив байт
 	ErrRange        = errors.New("bin: out of range")
+	ErrNegativeSize = errors.New("bin: negative size")
 )
 
 func ReadByteAsInt(r io.Reader) (i int, err error) {
@@ -1013,10 +1014,16 @@ func ReadBool(src io.Reader) (bool, error) {
 	return b == 1, nil
 }
 
-// uint64
+// READ/WRITE VAR SIZE
+
 func WriteVarSize(w io.Writer, n int) (int, error) {
-	num := uint64(n)
+	if n < 0 {
-	a := make([]byte, 9)
+		return 0, ErrNegativeSize
+	}
+	var (
+		num = uint64(n)
+		a   = make([]byte, 9)
+	)
 	for i := 0; i < 8; i++ {
 		a[i] = byte(num & 127)
 		num >>= 7
@@ -1100,3 +1107,55 @@ func CountVarSize(n int) int {
 	}
 	return 9
 }
+
+// PUT/GET VAR SIZE
+
+func PutVarSize(a []byte, n int) (int, error) {
+	if n < 0 {
+		return 0, ErrNegativeSize
+	}
+	var (
+		num = uint64(n)
+		tmp = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0}
+	)
+	for i := 0; i < 8; i++ {
+		if i < len(a) {
+			if num < 128 {
+				tmp[i] = byte(num) | 128
+				q := i + 1
+				copy(a, tmp[:q])
+				return q, nil
+			}
+			tmp[i] = byte(num & 127)
+			num >>= 7
+		} else {
+			return 0, ErrNoSpace
+		}
+	}
+	if len(a) < 9 {
+		return 0, ErrNoSpace
+	}
+	tmp[8] = byte(num)
+	copy(a, tmp)
+	return 9, nil
+}
+
+func GetVarSize(a []byte) (int, error) {
+	var num uint64
+	for i := 0; i < 8; i++ {
+		if i < len(a) {
+			b := a[i]
+			num |= uint64(b&127) << uint(i*7)
+			if b >= 128 {
+				return int(num), nil
+			}
+		} else {
+			return 0, ErrNoSpace
+		}
+	}
+	if len(a) < 9 {
+		return 0, ErrNoSpace
+	}
+	num |= uint64(a[8]) << 56
+	return int(num), nil
+}

little/little_test.go

@@ -361,7 +361,7 @@ func TestWriteReadInt16(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteInt16(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadInt16(w)
 		if err != nil {
@@ -383,7 +383,7 @@ func TestWriteReadInt24(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteInt24(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadInt24(w)
 		if err != nil {
@@ -405,7 +405,7 @@ func TestWriteReadInt32(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteInt32(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadInt32(w)
 		if err != nil {
@@ -427,7 +427,7 @@ func TestWriteReadInt48(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteInt48(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadInt48(w)
 		if err != nil {
@@ -449,7 +449,7 @@ func TestWriteReadInt64(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteInt64(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadInt64(w)
 		if err != nil {
@@ -471,7 +471,7 @@ func TestWriteReadUint16(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteUint16(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadUint16(w)
 		if err != nil {
@@ -492,7 +492,7 @@ func TestWriteReadUint24(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteUint24(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadUint24(w)
 		if err != nil {
@@ -513,7 +513,7 @@ func TestWriteReadUint32(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteUint32(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadUint32(w)
 		if err != nil {
@@ -534,7 +534,7 @@ func TestWriteReadUint48(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteUint48(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadUint48(w)
 		if err != nil {
@@ -555,7 +555,7 @@ func TestWriteReadUint64(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteUint64(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadUint64(w)
 		if err != nil {
@@ -582,7 +582,7 @@ func TestWriteReadFloat32(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteFloat32(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadFloat32(w)
 		if err != nil {
@@ -608,7 +608,7 @@ func TestWriteReadFloat64(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteFloat64(w, num)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadFloat64(w)
 		if err != nil {
@@ -633,7 +633,7 @@ func TestWriteReadString8(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteString8(w, origin)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadString8(w)
 		if err != nil {
@@ -662,7 +662,7 @@ func TestWriteReadString16(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteString16(w, origin)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadString16(w)
 		if err != nil {
@@ -691,7 +691,7 @@ func TestWriteReadBool(t *testing.T) {
 		w := bytes.NewBuffer(nil)
 		err := WriteBool(w, flag)
 		if err != nil {
-			return
+			t.Fatal(err)
 		}
 		decoded, err := ReadBool(w)
 		if err != nil {
@@ -761,8 +761,7 @@ func TestCountVarUint64(t *testing.T) {
 	}
 }
 
-func TestCountVarSize(t *testing.T) {
+var varSizeTestCases = []struct {
-	var testCases = []struct {
 	Num   int
 	Count int
 }{
@@ -784,7 +783,9 @@ func TestCountVarSize(t *testing.T) {
 	{Num: (1 << 56), Count: 9},
 	{Num: (1 << 63) - 1, Count: 9},
 }
-	for _, testCase := range testCases {
+
+func TestCountVarSize(t *testing.T) {
+	for _, testCase := range varSizeTestCases {
 		count := CountVarSize(testCase.Num)
 		if count != testCase.Count {
 			t.Fatalf("calculated count %d is not equal %d for num %d\n",
@@ -793,6 +794,60 @@ func TestCountVarSize(t *testing.T) {
 	}
 }
 
+func TestWriteReadVarSize(t *testing.T) {
+	for _, testCase := range varSizeTestCases {
+		w := bytes.NewBuffer(nil)
+		count, err := WriteVarSize(w, testCase.Num)
+		if err != nil {
+			t.Fatal(err)
+		}
+		decoded, err := ReadVarSize(w)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if decoded != testCase.Num {
+			t.Fatalf("num %d not equal decoded %d", testCase.Num, decoded)
+		}
+		if count != testCase.Count {
+			t.Fatalf("count %d not equal decoded count %d of num %d",
+				testCase.Count, count, testCase.Num)
+		}
+	}
+	// negative size
+	w := bytes.NewBuffer(nil)
+	_, err := WriteVarSize(w, -1)
+	if err != ErrNegativeSize {
+		t.Fatal("negative size did not lead to ErrNegativeSize")
+	}
+}
+
+func TestPutGetVarSize(t *testing.T) {
+	for _, testCase := range varSizeTestCases {
+		a := make([]byte, 9)
+		count, err := PutVarSize(a, testCase.Num)
+		if err != nil {
+			t.Fatal(err)
+		}
+		decoded, err := GetVarSize(a)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if decoded != testCase.Num {
+			t.Fatalf("num %d not equal decoded %d", testCase.Num, decoded)
+		}
+		if count != testCase.Count {
+			t.Fatalf("count %d not equal decoded count %d of num %d",
+				testCase.Count, count, testCase.Num)
+		}
+	}
+	// negative size
+	a := make([]byte, 9)
+	_, err := PutVarSize(a, -1)
+	if err != ErrNegativeSize {
+		t.Fatal("negative size did not lead to ErrNegativeSize")
+	}
+}
+
 // HELPERS
 
 const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"