grokify/mogo

// encoding provides generic encoding support.
package encoding

import "github.com/grokify/mogo/math/mathutil"

func Pad4(encoded, char string) string {
    inputLength := len(encoded)
    _, rem := mathutil.DivideInt64(int64(inputLength), int64(4))
    if rem == 0 {
        return encoded
    }
    if len(char) == 0 {
        char = " "
    }
    switch rem {
    case 1:
        rem = 3
    case 3:
        rem = 1
    }
    for i := 0; i < int(rem); i++ {
        encoded += char
    }
    return encoded[:inputLength+int(rem)]
}