Module MrMime_contentEncoding

module MrMime_contentEncoding: sig .. end

type mechanism = [ `Base64
       | `Binary
       | `Bit7
       | `Bit8
       | `Ietf_token of string
       | `QuotedPrintable
       | `X_token of string ] 

Kind of encoding. Many media types which could be usefully transported via email are represented, in their natural format, as `Bit8 character or `Binary data. Such data cannot be transmitted over some transfer protocols. For example, RFC821 (SMTP) restricts mail messages to `Bit7 US-ASCII data whitch lines no longer than 1000 characters including any trailing CRLF line separator.

Three transformations are currently defined: identity, the "quoted-printable" encoding, and the "base64" encoding. The domains are "binary", "8bit" and "7bit".

The "Content-Transfer-Encoding" values "7bit", "8bit", and "binary" all mean that the identity (i.e. No) encoding transformation has been performed. As such, they serve simply as indicators of the domain of the body data, and provide useful information about the sort of encoding that might be needed for transmission in a given transport system.

The "quoted-printable" and "base64" encodings transform their input from an arbitrary domain into material in the "7bit" range, thus making it safe to carry over restricted transports. You can see MrMime.QuotedPrintable for the "quoted-printable" decoding and MrMime.Base64 for the "base64" decoding.

type field = [ `ContentEncoding of mechanism ] 

It is necessary, therefore, to define a standard mechanism for encoding such data into a `Bit7 short line format. Proper labelling of unencoded material in less restrictive formats for direct use over less restrictive transports is also desirable. This module specifies that such encodings will be indicated by a new "Content-Transfer-Encoding" header field.

val pp : Format.formatter -> mechanism -> unit

pp mechanism prints an human readable representation of mechanism.

val default : mechanism

An encoding type of `Bit7 requires that the body is already in a `Bit7 mail-ready representation. This is the default value -- that is, "Content-Transfer-Encoding: 7BIT" is assumed if the "Content-Transfer-Encoding" header field is not present.

module Encoder: sig .. end

module Decoder: sig .. end

val of_string : ?chunk:int -> string -> mechanism option

of_string ~chunk:1024 buf parses an RFC2045 MrMime_contentEncoding.mechanism starting at 0 in buf.

This function allocates a internal buffer with chunk size (default to 1024).

val of_string_raw : ?chunk:int ->
       string -> int -> int -> (mechanism * int) option

of_string_raw ~chunk:1024 buff off len parses an RFC2045 MrMime_contentEncoding.mechanism starting at off in buf to a tuple (mechanism, count) with:

• mechanism the MrMime_contentEncoding.mechanism
• count the number of bytes read starting at off to parse the mechanism.

This function allocates a internal buffer with chunk size (default to 1024).