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authorPřemysl Janouch <p.janouch@gmail.com>2017-01-22 14:25:09 +0100
committerPřemysl Janouch <p.janouch@gmail.com>2017-01-22 14:25:09 +0100
commitb4cc98e63c38bd445978610839f64590f6fad570 (patch)
tree4b7287c59ec42746b5fa9a2e260b43a99bb438f3 /plugins
parenta20b09e80907a1e51775d35922cc2ab6cd7fb4b5 (diff)
downloadhex-b4cc98e63c38bd445978610839f64590f6fad570.tar.gz
hex-b4cc98e63c38bd445978610839f64590f6fad570.tar.xz
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Add a decoder for bencode
Diffstat (limited to 'plugins')
-rw-r--r--plugins/bencode.lua80
1 files changed, 80 insertions, 0 deletions
diff --git a/plugins/bencode.lua b/plugins/bencode.lua
new file mode 100644
index 0000000..8a704fd
--- /dev/null
+++ b/plugins/bencode.lua
@@ -0,0 +1,80 @@
+--
+-- 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
+ c (p, c.position -1):mark ("%d: container end", level - 1)
+ 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 }