PWGen/pwgenerator/funcs.go

package pwgenerator

import (
	"bytes"
	"crypto/rand"
	"math/big"
	"sort"
)

// sortDedupe sorts a slice of runes and deduplicates them.
func sortDedupe(charset *CharSet) {

	var vals map[Char]bool = make(map[Char]bool)
	var sorted CharSet
	var idx int

	// This inherently dedupes.
	for _, i := range *charset {
		vals[i] = true
	}

	// This handles sorting.
	sorted = make(CharSet, len(vals))
	// First we need a slice (again).
	for k := range vals {
		sorted[idx] = k
		idx++
	}
	// And now we can sort...
	sort.Sort(&sorted)

	// And replace the original charset with the sorted, deduplicated one.
	*charset = sorted

	return
}

/*
	saferRandInt uses crypto/rand instead of math/rand to get a random number.

	While this is cryptographically safer, I guarantee it's a much bigger pain to do.
*/
func saferRandInt(max int) (randInt int, err error) {

	var max64 int64 = int64(max)
	var cryptoInt *big.Int = big.NewInt(max64)
	var cryptoReader *bytes.Buffer = new(bytes.Buffer)
	var randInt64 int64

	if cryptoInt, err = rand.Int(cryptoReader, cryptoInt); err != nil {
		return
	}

	randInt64 = cryptoInt.Int64()

	randInt = int(randInt64)

	return
}