Přemysl Eric Janouch
019c4302ad
Lua detection functions used to cause fatal errors on failure to read. We could also reconsider treating detection errors as fatal.
55 lines
1.9 KiB
Lua
55 lines
1.9 KiB
Lua
--
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-- xcursor.lua: X11 cursors
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--
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-- Copyright (c) 2021, Přemysl Eric Janouch <p@janouch.name>
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--
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-- Permission to use, copy, modify, and/or distribute this software for any
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-- purpose with or without fee is hereby granted.
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--
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-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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-- SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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-- OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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-- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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--
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local detect = function (c)
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return #c >= 4 and c:read (4) == "Xcur"
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end
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-- https://www.x.org/releases/current/doc/man/man3/Xcursor.3.xhtml
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local decode = function (c)
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if not detect (c) then error ("not an Xcursor file") end
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-- libXcursor shows that they are always little-endian
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c (1, 4):mark ("Xcursor magic")
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c.endianity = "le"
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local size = c:u32 ("header size: %d")
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-- TODO: check the version, although it is essentially set in stone
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-- as 1.0, with X.org being a nearly abandoned project
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local version = c:u32 ("file version: %s", function (u32)
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return "%d.%d", u32 >> 16, u32 & 0xffff
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end)
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local ntoc = c:u32 ("number of ToC entries: %d")
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local i
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for i = 1, ntoc do
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local start = c.position
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local type = c:u32 ("entry type: %s", function (u32)
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if u32 == 0xfffe0001 then return "comment" end
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if u32 == 0xfffd0002 then return "image" end
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return "unknown: %d", u32
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end)
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local subtype = c:u32 ("entry subtype: %d")
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local position = c:u32 ("chunk position: %d")
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c (start, c.position - 1):mark (("ToC entry %d"):format (i))
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end
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-- TODO: decode all entries as well
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end
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hex.register { type="xcursor", detect=detect, decode=decode }
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