utils.go

/*
   ZAU Single Sign-On
   Copyright (C) 2021  Daniel A. Hawton <daniel@hawton.org>

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU Affero General Public License as published
   by the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

package main

import (
	"os"
	"unsafe"
)

func Getenv(key string, defaultValue string) string {
	val := os.Getenv(key)
	if len(val) == 0 {
		return defaultValue
	}
	return val
}

// StringToBytes converts string to byte slice without a memory allocation.
func StringToBytes(s string) []byte {
	return *(*[]byte)(unsafe.Pointer(
		&struct {
			string
			Cap int
		}{s, len(s)},
	))
}

// BytesToString converts byte slice to string without a memory allocation.
func BytesToString(b []byte) string {
	return *(*string)(unsafe.Pointer(&b))
}