Simplified file structure

src/sizeof/Signed.go

@@ -0,0 +1,20 @@
+package sizeof
+
+import "math"
+
+// Signed tells you how many bytes are needed to encode this signed number.
+func Signed(number int64) int {
+	switch {
+	case number >= math.MinInt8 && number <= math.MaxInt8:
+		return 1
+
+	case number >= math.MinInt16 && number <= math.MaxInt16:
+		return 2
+
+	case number >= math.MinInt32 && number <= math.MaxInt32:
+		return 4
+
+	default:
+		return 8
+	}
+}

src/sizeof/Signed_test.go

@@ -0,0 +1,21 @@
+package sizeof_test
+
+import (
+	"math"
+	"testing"
+
+	"git.akyoto.dev/cli/q/src/sizeof"
+	"git.akyoto.dev/go/assert"
+)
+
+func TestSigned(t *testing.T) {
+	assert.Equal(t, sizeof.Signed(0), 1)
+	assert.Equal(t, sizeof.Signed(math.MinInt8), 1)
+	assert.Equal(t, sizeof.Signed(math.MaxInt8), 1)
+	assert.Equal(t, sizeof.Signed(math.MinInt16), 2)
+	assert.Equal(t, sizeof.Signed(math.MaxInt16), 2)
+	assert.Equal(t, sizeof.Signed(math.MinInt32), 4)
+	assert.Equal(t, sizeof.Signed(math.MaxInt32), 4)
+	assert.Equal(t, sizeof.Signed(math.MinInt64), 8)
+	assert.Equal(t, sizeof.Signed(math.MaxInt64), 8)
+}

src/sizeof/Unsigned.go

@@ -0,0 +1,20 @@
+package sizeof
+
+import "math"
+
+// Unsigned tells you how many bytes are needed to encode this unsigned number.
+func Unsigned(number uint64) int {
+	switch {
+	case number <= math.MaxUint8:
+		return 1
+
+	case number <= math.MaxUint16:
+		return 2
+
+	case number <= math.MaxUint32:
+		return 4
+
+	default:
+		return 8
+	}
+}

src/sizeof/Unsigned_test.go

@@ -0,0 +1,17 @@
+package sizeof_test
+
+import (
+	"math"
+	"testing"
+
+	"git.akyoto.dev/cli/q/src/sizeof"
+	"git.akyoto.dev/go/assert"
+)
+
+func TestUnsigned(t *testing.T) {
+	assert.Equal(t, sizeof.Unsigned(0), 1)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint8), 1)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint16), 2)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint32), 4)
+	assert.Equal(t, sizeof.Unsigned(math.MaxUint64), 8)
+}