initial

lualib/mime.lua

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+-----------------------------------------------------------------------------
+-- MIME support for the Lua language.
+-- Author: Diego Nehab
+-- Conforming to RFCs 2045-2049
+-- RCS ID: $Id: mime.lua,v 1.29 2007/06/11 23:44:54 diego Exp $
+-----------------------------------------------------------------------------
+
+-----------------------------------------------------------------------------
+-- Declare module and import dependencies
+-----------------------------------------------------------------------------
+local base = _G
+local ltn12 = require("ltn12")
+local mime = require("mime.core")
+--local io = require("io")
+local string = require("string")
+module("mime")
+
+-- encode, decode and wrap algorithm tables
+encodet = {}
+decodet = {}
+wrapt = {}
+
+-- creates a function that chooses a filter by name from a given table
+local function choose(table)
+    return function(name, opt1, opt2)
+        if base.type(name) ~= "string" then
+            name, opt1, opt2 = "default", name, opt1
+        end
+        local f = table[name or "nil"]
+        if not f then 
+            base.error("unknown key (" .. base.tostring(name) .. ")", 3)
+        else return f(opt1, opt2) end
+    end
+end
+
+-- define the encoding filters
+encodet['base64'] = function()
+    return ltn12.filter.cycle(b64, "")
+end
+
+encodet['quoted-printable'] = function(mode)
+    return ltn12.filter.cycle(qp, "",
+        (mode == "binary") and "=0D=0A" or "\r\n")
+end
+
+-- define the decoding filters
+decodet['base64'] = function()
+    return ltn12.filter.cycle(unb64, "")
+end
+
+decodet['quoted-printable'] = function()
+    return ltn12.filter.cycle(unqp, "")
+end
+
+local function format(chunk)
+    if chunk then
+        if chunk == "" then return "''"
+        else return string.len(chunk) end
+    else return "nil" end
+end
+
+-- define the line-wrap filters
+wrapt['text'] = function(length)
+    length = length or 76
+    return ltn12.filter.cycle(wrp, length, length)
+end
+wrapt['base64'] = wrapt['text']
+wrapt['default'] = wrapt['text']
+
+wrapt['quoted-printable'] = function()
+    return ltn12.filter.cycle(qpwrp, 76, 76)
+end
+
+-- function that choose the encoding, decoding or wrap algorithm
+encode = choose(encodet)
+decode = choose(decodet)
+wrap = choose(wrapt)
+
+-- define the end-of-line normalization filter
+function normalize(marker)
+    return ltn12.filter.cycle(eol, 0, marker)
+end
+
+-- high level stuffing filter
+function stuff()
+    return ltn12.filter.cycle(dot, 2)
+end