BASE64DECODE Perform base64 decoding on a string.
BASE64DECODE(STR) decodes the given base64 string STR.
Any character not part of the 65-character base64 subset set is silently
ignored. Characters occuring after a ‘=’ padding character are never
STR doesn’t have to be a string. The only requirement is that it is a
vector containing values in the range 0-255.
If the length of the string to decode (after ignoring non-base64 chars) is
not a multiple of 4, then a warning is generated.
This function is used to decode strings from the Base64 encoding specified
in RFC 2045 - MIME (Multipurpose Internet Mail Extensions). The Base64
encoding is designed to represent arbitrary sequences of octets in a form
that need not be humanly readable. A 65-character subset ([A-Za-z0-9+/=])
of US-ASCII is used, enabling 6 bits to be represented per printable
See also BASE64ENCODE.