rewrite in go and compile to wasm

pkg/custom_slice.go

@@ -0,0 +1,97 @@
+package wfa
+
+type IntegerSlice[T any] struct {
+	data         []T
+	valid        []bool
+	defaultValue T
+}
+
+func (a *IntegerSlice[T]) TranslateIndex(idx int) int {
+	if idx >= 0 { // 0 -> 0, 1 -> 2, 2 -> 4, 3 -> 6, ...
+		return 2 * idx
+	} else { // -1 -> 1, -2 -> 3, -3 -> 5, ...
+		return (-2 * idx) - 1
+	}
+}
+
+func (a *IntegerSlice[T]) Valid(idx int) bool {
+	actualIdx := a.TranslateIndex(idx)
+	if actualIdx < len(a.valid) { // idx is in the slice
+		return a.valid[actualIdx]
+	} else { // idx is out of the slice
+		return false
+	}
+}
+
+func (a *IntegerSlice[T]) Get(idx int) T {
+	actualIdx := a.TranslateIndex(idx)
+	if actualIdx < len(a.valid) { // idx is in the slice
+		return a.data[actualIdx]
+	} else { // idx is out of the slice
+		return a.defaultValue
+	}
+}
+
+func (a *IntegerSlice[T]) Set(idx int, value T) {
+	actualIdx := a.TranslateIndex(idx)
+	if actualIdx >= len(a.valid) { // idx is outside the slice
+		// expand data array to actualIdx
+		newData := make([]T, actualIdx+1)
+		copy(newData, a.data)
+		a.data = newData
+
+		// expand valid array to actualIdx
+		newValid := make([]bool, actualIdx+1)
+		copy(newValid, a.valid)
+		a.valid = newValid
+	}
+
+	a.data[actualIdx] = value
+	a.valid[actualIdx] = true
+}
+
+type PositiveSlice[T any] struct {
+	data         []T
+	valid        []bool
+	defaultValue T
+}
+
+func (a *PositiveSlice[T]) TranslateIndex(idx int) int {
+	return idx
+}
+
+func (a *PositiveSlice[T]) Valid(idx int) bool {
+	actualIdx := a.TranslateIndex(idx)
+	if actualIdx >= 0 && actualIdx < len(a.valid) { // idx is in the slice
+		return a.valid[actualIdx]
+	} else { // idx is out of the slice
+		return false
+	}
+}
+
+func (a *PositiveSlice[T]) Get(idx int) T {
+	actualIdx := a.TranslateIndex(idx)
+	if actualIdx >= 0 && actualIdx < len(a.valid) { // idx is in the slice
+		return a.data[actualIdx]
+	} else { // idx is out of the slice
+		return a.defaultValue
+	}
+}
+
+func (a *PositiveSlice[T]) Set(idx int, value T) {
+	actualIdx := a.TranslateIndex(idx)
+	if actualIdx < 0 || actualIdx >= len(a.valid) { // idx is outside the slice
+		// expand data array to actualIdx
+		newData := make([]T, actualIdx+1)
+		copy(newData, a.data)
+		a.data = newData
+
+		// expand valid array to actualIdx
+		newValid := make([]bool, actualIdx+1)
+		copy(newValid, a.valid)
+		a.valid = newValid
+	}
+
+	a.data[actualIdx] = value
+	a.valid[actualIdx] = true
+}