Initial QSfera import

Server/vendor/github.com/gookit/goutil/reflects/slice.go

@@ -0,0 +1,61 @@
+package reflects
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// MakeSliceByElem create a new slice by the element type.
+//
+// - elType: the type of the element.
+// - returns: the new slice.
+//
+// Usage:
+//
+//	sl := MakeSliceByElem(reflect.TypeOf(1), 10, 20)
+//	sl.Index(0).SetInt(10)
+//
+//	// Or use reflect.AppendSlice() merge two slice
+//	// Or use `for` with `reflect.Append()` add elements
+func MakeSliceByElem(elTyp reflect.Type, len, cap int) reflect.Value {
+	return reflect.MakeSlice(reflect.SliceOf(elTyp), len, cap)
+}
+
+// FlatSlice flatten multi-level slice to given depth-level slice.
+//
+// Example:
+//
+//	FlatSlice([]any{ []any{3, 4}, []any{5, 6} }, 1) // Output: []any{3, 4, 5, 6}
+//
+// always return reflect.Value of []any. note: maybe flatSl.Cap != flatSl.Len
+func FlatSlice(sl reflect.Value, depth int) reflect.Value {
+	items := make([]reflect.Value, 0, sl.Cap())
+	slCap := addSliceItem(sl, depth, func(item reflect.Value) {
+		items = append(items, item)
+	})
+
+	flatSl := reflect.MakeSlice(reflect.SliceOf(anyType), 0, slCap)
+	flatSl = reflect.Append(flatSl, items...)
+
+	return flatSl
+}
+
+func addSliceItem(sl reflect.Value, depth int, collector func(item reflect.Value)) (c int) {
+	for i := 0; i < sl.Len(); i++ {
+		v := Elem(sl.Index(i))
+
+		if depth > 0 {
+			if v.Kind() != reflect.Slice {
+				panic(fmt.Sprintf("depth: %d, the value of index %d is not slice", depth, i))
+			}
+			c += addSliceItem(v, depth-1, collector)
+		} else {
+			collector(v)
+		}
+	}
+
+	if depth == 0 {
+		c = sl.Cap()
+	}
+	return c
+}