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|
-- stylua: ignore start
-- zzlib - zlib decompression in Lua - Implementation-independent code
-- Copyright (c) 2016-2023 Francois Galea <fgalea at free.fr>
-- This program is free software. It comes without any warranty, to
-- the extent permitted by applicable law. You can redistribute it
-- and/or modify it under the terms of the Do What The Fuck You Want
-- To Public License, Version 2, as published by Sam Hocevar. See
-- the COPYING file or http://www.wtfpl.net/ for more details.
local unpack = table.unpack or unpack
local infl
local lua_version = tonumber(_VERSION:match("^Lua (.*)"))
if not lua_version or lua_version < 5.3 then
-- older version of Lua or Luajit being used - use bit/bit32-based implementation
infl = require("mason-vendor.zzlib.inflate-bit32")
else
-- From Lua 5.3, use implementation based on bitwise operators
infl = require("mason-vendor.zzlib.inflate-bwo")
end
local zzlib = {}
local function arraytostr(array)
local tmp = {}
local size = #array
local pos = 1
local imax = 1
while size > 0 do
local bsize = size>=2048 and 2048 or size
local s = string.char(unpack(array,pos,pos+bsize-1))
pos = pos + bsize
size = size - bsize
local i = 1
while tmp[i] do
s = tmp[i]..s
tmp[i] = nil
i = i + 1
end
if i > imax then
imax = i
end
tmp[i] = s
end
local str = ""
for i=1,imax do
if tmp[i] then
str = tmp[i]..str
end
end
return str
end
local function inflate_gzip(bs)
local id1,id2,cm,flg = bs.buf:byte(1,4)
if id1 ~= 31 or id2 ~= 139 then
error("invalid gzip header")
end
if cm ~= 8 then
error("only deflate format is supported")
end
bs.pos=11
if infl.band(flg,4) ~= 0 then
local xl1,xl2 = bs.buf.byte(bs.pos,bs.pos+1)
local xlen = xl2*256+xl1
bs.pos = bs.pos+xlen+2
end
if infl.band(flg,8) ~= 0 then
local pos = bs.buf:find("\0",bs.pos)
bs.pos = pos+1
end
if infl.band(flg,16) ~= 0 then
local pos = bs.buf:find("\0",bs.pos)
bs.pos = pos+1
end
if infl.band(flg,2) ~= 0 then
-- TODO: check header CRC16
bs.pos = bs.pos+2
end
local result = arraytostr(infl.main(bs))
local crc = bs:getb(8)+256*(bs:getb(8)+256*(bs:getb(8)+256*bs:getb(8)))
bs:close()
if crc ~= infl.crc32(result) then
error("checksum verification failed")
end
return result
end
-- compute Adler-32 checksum
local function adler32(s)
local s1 = 1
local s2 = 0
for i=1,#s do
local c = s:byte(i)
s1 = (s1+c)%65521
s2 = (s2+s1)%65521
end
return s2*65536+s1
end
local function inflate_zlib(bs)
local cmf = bs.buf:byte(1)
local flg = bs.buf:byte(2)
if (cmf*256+flg)%31 ~= 0 then
error("zlib header check bits are incorrect")
end
if infl.band(cmf,15) ~= 8 then
error("only deflate format is supported")
end
if infl.rshift(cmf,4) ~= 7 then
error("unsupported window size")
end
if infl.band(flg,32) ~= 0 then
error("preset dictionary not implemented")
end
bs.pos=3
local result = arraytostr(infl.main(bs))
local adler = ((bs:getb(8)*256+bs:getb(8))*256+bs:getb(8))*256+bs:getb(8)
bs:close()
if adler ~= adler32(result) then
error("checksum verification failed")
end
return result
end
local function inflate_raw(buf,offset,crc)
local bs = infl.bitstream_init(buf)
bs.pos = offset
local result = arraytostr(infl.main(bs))
if crc and crc ~= infl.crc32(result) then
error("checksum verification failed")
end
return result
end
function zzlib.gunzipf(filename)
local file,err = io.open(filename,"rb")
if not file then
return nil,err
end
return inflate_gzip(infl.bitstream_init(file))
end
function zzlib.gunzip(str)
return inflate_gzip(infl.bitstream_init(str))
end
function zzlib.inflate(str)
return inflate_zlib(infl.bitstream_init(str))
end
local function int2le(str,pos)
local a,b = str:byte(pos,pos+1)
return b*256+a
end
local function int4le(str,pos)
local a,b,c,d = str:byte(pos,pos+3)
return ((d*256+c)*256+b)*256+a
end
local function nextfile(buf,p)
if int4le(buf,p) ~= 0x02014b50 then
-- end of central directory list
return
end
-- local flag = int2le(buf,p+8)
local packed = int2le(buf,p+10)~=0
local crc = int4le(buf,p+16)
local namelen = int2le(buf,p+28)
local name = buf:sub(p+46,p+45+namelen)
local offset = int4le(buf,p+42)+1
p = p+46+namelen+int2le(buf,p+30)+int2le(buf,p+32)
if int4le(buf,offset) ~= 0x04034b50 then
error("invalid local header signature")
end
local size = int4le(buf,offset+18)
local extlen = int2le(buf,offset+28)
offset = offset+30+namelen+extlen
return p,name,offset,size,packed,crc
end
function zzlib.files(buf)
local p = #buf-21
if int4le(buf,p) ~= 0x06054b50 then
-- not sure there is a reliable way to locate the end of central directory record
-- if it has a variable sized comment field
error(".ZIP file comments not supported")
end
local cdoffset = int4le(buf,p+16)+1
return nextfile,buf,cdoffset
end
function zzlib.unzip(buf,arg1,arg2)
if type(arg1) == "number" then
-- mode 1: unpack data from specified position in zip file
return inflate_raw(buf,arg1,arg2)
end
-- mode 2: search and unpack file from zip file
local filename = arg1
for _,name,offset,size,packed,crc in zzlib.files(buf) do
if name == filename then
local result
if not packed then
-- no compression
result = buf:sub(offset,offset+size-1)
else
-- DEFLATE compression
result = inflate_raw(buf,offset,crc)
end
return result
end
end
error("file '"..filename.."' not found in ZIP archive")
end
return zzlib
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