did something

vendor/periph.io/x/conn/v3/pin/func.go

@@ -0,0 +1,58 @@
+// Copyright 2018 The Periph Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package pin
+
+import (
+	"strconv"
+	"strings"
+)
+
+// Func is a pin function.
+//
+// The Func format must be "[A-Z]+", "[A-Z]+_[A-Z]+" or exceptionally
+// "(In|Out)/(Low|High)".
+type Func string
+
+// FuncNone is returned by PinFunc.Func() for a Pin without an active
+// functionality.
+const FuncNone Func = ""
+
+// Specialize converts a "BUS_LINE" function and appends the bug number and
+// line number, to look like "BUS0_LINE1".
+//
+// Use -1 to not add a bus or line number.
+func (f Func) Specialize(b, l int) Func {
+	if f == FuncNone {
+		return FuncNone
+	}
+	if b != -1 {
+		parts := strings.SplitN(string(f), "_", 2)
+		if len(parts) == 1 {
+			return FuncNone
+		}
+		f = Func(parts[0] + strconv.Itoa(b) + "_" + parts[1])
+	}
+	if l != -1 {
+		f += Func(strconv.Itoa(l))
+	}
+	return f
+}
+
+// Generalize is the reverse of Specialize().
+func (f Func) Generalize() Func {
+	parts := strings.SplitN(string(f), "_", 2)
+	f = Func(strings.TrimRightFunc(parts[0], isNum))
+	if len(parts) == 2 {
+		f += "_"
+		f += Func(strings.TrimRightFunc(parts[1], isNum))
+	}
+	return f
+}
+
+//
+
+func isNum(r rune) bool {
+	return r >= '0' && r <= '9'
+}