hex/plugins/bencode.lua

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--
-- bencode.lua: BitTorrent data encoding
--
-- Copyright (c) 2017, Přemysl Janouch <p.janouch@gmail.com>
--
-- Permission to use, copy, modify, and/or distribute this software for any
-- purpose with or without fee is hereby granted, provided that the above
-- copyright notice and this permission notice appear in all copies.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
-- SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
-- OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
-- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
--
local detect = function (c)
-- There is no magic to go by
return false
end
-- We're not making it exactly readable but at least we're trying
local function one_value (c, level)
local p, type = c.position, c:read (1)
if type == "e" then
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c (p, c.position - 1):mark ("%d: container end", level - 1)
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return false
elseif type == "i" then
local n = ""
type = c:read (1)
while type ~= "e" do
n = n .. type
type = c:read (1)
end
c (p, c.position - 1):mark ("%d: integer: %s", level, n)
elseif type == "l" then
c (p, p):mark ("%d: list begin", level)
local i = 0
while true do
local p = c.position
if not one_value (c, level + 1) then break end
c (p, c.position - 1):mark ("%d: list value %d", level, i)
i = i + 1
end
elseif type == "d" then
c (p, p):mark ("%d: dictionary begin", level)
while true do
local p = c.position
if not one_value (c, level + 1) then break end
c (p, c.position - 1):mark ("%d: dictionary key", level)
local p = c.position
if not one_value (c, level + 1) then break end
c (p, c.position - 1):mark ("%d: dictionary value", level)
end
else
local n = type
type = c:read (1)
while type ~= ":" do
n = n .. type
type = c:read (1)
end
c (p, c.position - 1):mark ("%d: string length: %s", level, n)
p = c.position
c:read (tonumber (n))
c (p, c.position - 1):mark ("%d: string value", level)
end
return true
end
local decode = function (c)
while not c.eof do
one_value (c, 0)
end
end
hex.register { type="bencode", detect=detect, decode=decode }