internal: get rid of architecture specific constants (#191)

internal/c/const.go

@@ -6,6 +6,20 @@ import (
 	"math/big"
 )
 
+const (
+	is64bit = 1 << (^uintptr(0) >> 63) / 2 // 0 or 1
+	is32bit = is64bit &^ 1                 // 0 or 1
+
+	maxScale32    = 425000000
+	maxScaleInf32 = 1000000001
+
+	maxScale64    = 999999999999999999
+	maxScaleInf64 = 2000000000000000001
+
+	MaxScale    = maxScale32*is32bit + maxScale64*is64bit
+	MaxScaleInf = maxScaleInf32*is32bit + maxScaleInf64*is64bit
+)
+
 const Inflated uint64 = math.MaxUint64
 
 var (

internal/c/const_test.go

@@ -0,0 +1,37 @@
+package c
+
+import (
+	"math/bits"
+	"testing"
+)
+
+func TestMaxScale(t *testing.T) {
+	check := func(t *testing.T, max int64, maxInf int64) {
+		if MaxScale != max {
+			t.Fatalf("MaxScale: got %d, expected %d", MaxScale, max)
+		}
+		if MaxScaleInf != maxInf {
+			t.Fatalf("MaxScaleInf: got %d, expected %d", MaxScaleInf, maxInf)
+		}
+	}
+	switch n := bits.UintSize; n {
+	case 32:
+		if is32bit != 1 {
+			t.Fatalf("is32bit: got %d, expected %d", is32bit, 1)
+		}
+		if is64bit != 0 {
+			t.Fatalf("is64bit: got %d, expected %d", is64bit, 0)
+		}
+		check(t, maxScale32, maxScaleInf32)
+	case 64:
+		if is32bit != 0 {
+			t.Fatalf("is32bit: got %d, expected %d", is32bit, 0)
+		}
+		if is64bit != 1 {
+			t.Fatalf("is64bit: got %d, expected %d", is64bit, 1)
+		}
+		check(t, maxScale64, maxScaleInf64)
+	default:
+		t.Fatalf("unknown bit size: %d", n)
+	}
+}