formatter.go

// Copyright © 2018, 2019 Weald Technology Trading
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package merkletree

import "fmt"

// Formatter formats a []byte in to a string.
// It is used by DOT() to provide users with the required format for the graphical display of their Merkle trees.
type Formatter interface {
	// Format
	Format(data []byte) string
}

// TruncatedHexFormatter shows only the first and last two bytes of the value.
type TruncatedHexFormatter struct{}

// Format formats a value as truncated hex, showing the first and last four characers of the hex string.
func (*TruncatedHexFormatter) Format(data []byte) string {
	return fmt.Sprintf("%4x…%4x", data[0:2], data[len(data)-2:])
}

// HexFormatter shows the entire value.
type HexFormatter struct{}

// Format formats a value as a full hex string.
func (*HexFormatter) Format(data []byte) string {
	return fmt.Sprintf("%0x", data)
}

// StringFormatter shows the entire value as a string.
type StringFormatter struct{}

// Format formats a value as a UTF-8 string.
func (*StringFormatter) Format(data []byte) string {
	return string(data)
}