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|
if not modules then modules = { } end modules ['l-gzip'] = {
version = 1.001,
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- We only have a few official methods here:
--
-- local decompressed = gzip.load (filename)
-- local resultsize = gzip.save (filename,compresslevel)
-- local compressed = gzip.compress (str,compresslevel)
-- local decompressed = gzip.decompress (str)
-- local iscompressed = gzip.compressed (str)
-- local suffix, okay = gzip.suffix (filename)
--
-- In LuaMetaTeX we have only xzip which implements a very few methods:
--
-- compress (str,level,method,window,memory,strategy)
-- decompress (str,window)
-- adler32 (str,checksum)
-- crc32 (str,checksum)
--
-- Special window values are:
--
-- flate : - 15
-- zlib : 15
-- gzip : 15 | 16
-- auto : 15 | 32
gzip = gzip or { } -- so in luatex we keep the old ones too
if not zlib then
zlib = xzip -- in luametatex we shadow the old one
elseif not xzip then
xzip = zlib
end
if zlib then
local suffix = file.suffix
local suffixes = file.suffixes
local find = string.find
local openfile = io.open
local gzipwindow = 15 + 16 -- +16: gzip, +32: gzip|zlib
local gziplevel = 3
local identifier = "^\x1F\x8B\x08"
local compress = zlib.compress
local decompress = zlib.decompress
function gzip.load(filename)
local f = openfile(filename,"rb")
if not f then
-- invalid file
else
local data = f:read("*all")
f:close()
if data and data ~= "" then
if suffix(filename) == "gz" then
data = decompress(data,gzipwindow)
end
return data
end
end
end
function gzip.save(filename,data,level)
if suffix(filename) ~= "gz" then
filename = filename .. ".gz"
end
local f = openfile(filename,"wb")
if f then
data = compress(data or "",level or gziplevel,nil,gzipwindow)
f:write(data)
f:close()
return #data
end
end
function gzip.suffix(filename)
local suffix, extra = suffixes(filename)
local gzipped = extra == "gz"
return suffix, gzipped
end
function gzip.compressed(s)
return s and find(s,identifier)
end
function gzip.compress(s,level)
if s and not find(s,identifier) then -- the find check might go away
if not level then
level = gziplevel
elseif level <= 0 then
return s
elseif level > 9 then
level = 9
end
return compress(s,level or gziplevel,nil,gzipwindow) or s
end
end
function gzip.decompress(s)
if s and find(s,identifier) then
return decompress(s,gzipwindow)
else
return s
end
end
end
-- In luametatex we can use this one but it doesn't look like there wil be stream
-- support so for now we still use zlib (the performance difference is not that
-- spectacular in our usage.
-- if flate then
--
-- local type = type
-- local find = string.find
--
-- local compress = flate.gz_compress
-- local decompress = flate.gz_decompress
--
-- local absmax = 128*1024*1024
-- local initial = 64*1024
-- local identifier = "^\x1F\x8B\x08"
--
-- function gzip.compressed(s)
-- return s and find(s,identifier)
-- end
--
-- function gzip.compress(s,level)
-- if s and not find(s,identifier) then -- the find check might go away
-- if not level then
-- level = 3
-- elseif level <= 0 then
-- return s
-- elseif level > 9 then
-- level = 9
-- end
-- return compress(s,level) or s
-- end
-- end
--
-- function gzip.decompress(s,size,iterate)
-- if s and find(s,identifier) then
-- if type(size) ~= "number" then
-- size = initial
-- end
-- if size > absmax then
-- size = absmax
-- end
-- if type(iterate) == "number" then
-- max = size * iterate
-- elseif iterate == nil or iterate == true then
-- iterate = true
-- max = absmax
-- end
-- if max > absmax then
-- max = absmax
-- end
-- while true do
-- local d = decompress(s,size)
-- if d then
-- return d
-- end
-- size = 2 * size
-- if not iterate or size > max then
-- return false
-- end
-- end
-- else
-- return s
-- end
-- end
--
-- end
|
