Description

There are many protocols, like classic UNIX uuencode, which are used to transmit binary files over transmission mediums that do not support other than simple ASCII data. The epoch of physical lines of such sort is in past but file attachments in most popular mail systems still follow old regulations.

Encoded data are transmitted as a sequence of one or more "sections". They may be stored or sent as independent documents. Every section contains some range of original document's data. They may be decoded one after another, and original document may be composed by concatenation of decoded fragments. If the document is small (or if there's no limit on the size of message), it may be sent as single section.

Every section has some header and footer and a set of lines with data between them. Headers and especially footers are usually optional and may vary from system to system whereas data lines are described by standards. Data lines of any two consequent sections may be concatenated together, if needed, to create longer section.

uuencode creates a vector of strings, where every string contains some number of data lines, without headers or footers. A Virtuoso/PL stored procedure may be used to create some output stream(s) and put there sections of appropriate format with data lines from vector. Every item of the created vector will contain up to maxlines lines of data, usually 60 to 80 bytes per line; maxlines may vary from 10 to 120000 so section may be 0.8Kb to 10Mb long depending on your choice. Last section may be shorter than other, if only partially filled. 10Mb limit may be bypassed by sending of sections one after another without intermediate footers or headers, but please keep in mind that you cannot concatenate two strings in memory if the sum of their lengths exceeds system-wide 10Mb.

RFC 2045, (N. Borenstein, N. Freed. MIME (Multipurpose Internet Mail Extensions) Part One: The Format of Internet Message Bodies), contains detailed description of most important encodings used by mail systems. Older RFC 1521 is now obsoleted.

Currently, eight conventions are used for mail attachments. In Virtuoso, they are enumerated by integer IDs.

Parameters

Return Types

Vector of strings, where every string contains all data lines of a section.

Errors

Examples

-- Line 4:
create procedure BINHEX_ENCODE (in txt varchar, in lines_per_section integer)
{
  declare SECTION varchar;
  declare sections any;
  result_names (SECTION);
  sections := uuencode (txt, 5, lines_per_section);
  foreach (varchar sect in sections) do
    result (':' || sect);
}

Done. -- 00000 msec.

BINHEX_ENCODE ('Hello', 10)
SECTION
VARCHAR
_______________________________________________________________________________

:5'9XE'm:

1 Rows. -- 00000 msec.

BINHEX_ENCODE (repeat ('Hello', 100), 10)
SECTION
VARCHAR
_______________________________________________________________________________

:5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[

:5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[5'9XE'p)C@aXEdKPE'a[
5'9XE'm:

2 Rows. -- 00000 msec.

See Also

uudecode , uuvalidate