Base 64 code is used in email to encode a sequence of 8-bit bytes as a longer sequence of ASCII graphic characters. It is defined in Internet RFC232045 and also in RFC 4648. This section describes the functions for converting to and from this code.
This function converts the region from beg to end into base 64 code. It returns the length of the encoded text. An error is signaled if a character in the region is multibyte, i.e., in a multibyte buffer the region must contain only ASCII characters or raw bytes.
Normally, this function inserts newline characters into the encoded
text, to avoid overlong lines. However, if the optional argument
no-line-break is non-nil, these newlines are not added, so
the output is just one long line.
This function is like base64-encode-region, but it implements
the URL variant of base 64 encoding, per RFC 4648, and it doesn’t
insert newline characters into the encoded text, so the output is
just one long line.
If the optional argument no-pad is non-nil then this
function doesn’t generate the padding (=).
This function converts the string string into base 64 code. It
returns a string containing the encoded text. As for
base64-encode-region, an error is signaled if a character in the
string is multibyte.
Normally, this function inserts newline characters into the encoded
text, to avoid overlong lines. However, if the optional argument
no-line-break is non-nil, these newlines are not added, so
the result string is just one long line.
Like base64-encode-string, but generates the URL variant of
base 64, and doesn’t insert newline characters into the encoded text,
so the result is just one long line.
If the optional argument no-pad is non-nil then this
function doesn’t generate the padding.
This function converts the region from beg to end from base 64 code into the corresponding decoded text. It returns the length of the decoded text.
The decoding functions ignore newline characters in the encoded text.
If optional argument base64url is non-nil, then padding
is optional, and the URL variant of base 64 encoding is used.
If optional argument ignore-invalid is non-nil, then any
unrecognized characters are ignored.
This function converts the string string from base 64 code into the corresponding decoded text. It returns a unibyte string containing the decoded text.
The decoding functions ignore newline characters in the encoded text.
If optional argument base64url is non-nil, then padding
is optional, and the URL variant of base 64 encoding is used.
If optional argument ignore-invalid is non-nil, then any
unrecognized characters are ignored.
An RFC, an acronym for Request for Comments, is a numbered Internet informational document describing a standard. RFCs are usually written by technical experts acting on their own initiative, and are traditionally written in a pragmatic, experience-driven manner.