util.go

// Copyright © 2018 Immutability, LLC
//
// 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 main

import (
	"bytes"
	"crypto/ecdsa"
	"encoding/hex"
	"encoding/json"
	"io/ioutil"
	"os"
)

// PrettyPrint prints an indented JSON payload. This is used for development debugging.
func PrettyPrint(v interface{}) string {
	jsonString, _ := json.Marshal(v)
	var out bytes.Buffer
	json.Indent(&out, jsonString, "", "  ")
	return out.String()
}

// Dedup removes duplicates from a list
func Dedup(stringSlice []string) []string {
	var returnSlice []string
	for _, value := range stringSlice {
		if !Contains(returnSlice, value) {
			returnSlice = append(returnSlice, value)
		}
	}
	return returnSlice
}

// Contains returns true if an element is present in a list
func Contains(stringSlice []string, searchString string) bool {
	for _, value := range stringSlice {
		if value == searchString {
			return true
		}
	}
	return false
}

// ZeroKey removes the key from memory
func ZeroKey(k *ecdsa.PrivateKey) {
	b := k.D.Bits()
	for i := range b {
		b[i] = 0
	}
}

// ReadFile returns the contents of a file
func ReadFile(path string) ([]byte, error) {
	var contents []byte
	file, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	contents, err = ioutil.ReadFile(path)
	if err != nil {
		return nil, err
	}
	return contents, nil

}

// Decode will decode the hex
func Decode(src []byte) ([]byte, error) {
	raw := make([]byte, hex.EncodedLen(len(src)))
	n, err := hex.Decode(raw, src)
	if err != nil {
		return nil, err
	}
	raw = raw[:n]
	return raw[:], nil
}