diff options
Diffstat (limited to 'lua/mason-vendor/zzlib/inflate-bit32.lua')
| -rw-r--r-- | lua/mason-vendor/zzlib/inflate-bit32.lua | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/lua/mason-vendor/zzlib/inflate-bit32.lua b/lua/mason-vendor/zzlib/inflate-bit32.lua new file mode 100644 index 00000000..fc426018 --- /dev/null +++ b/lua/mason-vendor/zzlib/inflate-bit32.lua @@ -0,0 +1,285 @@ +-- stylua: ignore start + +-- zzlib-bit32 - zlib decompression in Lua - version using bit/bit32 libraries + +-- 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 inflate = {} + +local bit = bit32 or bit + +inflate.band = bit.band +inflate.rshift = bit.rshift + +function inflate.bitstream_init(file) + local bs = { + file = file, -- the open file handle + buf = nil, -- character buffer + len = nil, -- length of character buffer + pos = 1, -- position in char buffer, next to be read + b = 0, -- bit buffer + n = 0, -- number of bits in buffer + } + -- get rid of n first bits + function bs:flushb(n) + self.n = self.n - n + self.b = bit.rshift(self.b,n) + end + -- returns the next byte from the stream, excluding any half-read bytes + function bs:next_byte() + if self.pos > self.len then + self.buf = self.file:read(4096) + self.len = self.buf:len() + self.pos = 1 + end + local pos = self.pos + self.pos = pos + 1 + return self.buf:byte(pos) + end + -- peek a number of n bits from stream + function bs:peekb(n) + while self.n < n do + self.b = self.b + bit.lshift(self:next_byte(),self.n) + self.n = self.n + 8 + end + return bit.band(self.b,bit.lshift(1,n)-1) + end + -- get a number of n bits from stream + function bs:getb(n) + local ret = bs:peekb(n) + self.n = self.n - n + self.b = bit.rshift(self.b,n) + return ret + end + -- get next variable-size of maximum size=n element from stream, according to Huffman table + function bs:getv(hufftable,n) + local e = hufftable[bs:peekb(n)] + local len = bit.band(e,15) + local ret = bit.rshift(e,4) + self.n = self.n - len + self.b = bit.rshift(self.b,len) + return ret + end + function bs:close() + if self.file then + self.file:close() + end + end + if type(file) == "string" then + bs.file = nil + bs.buf = file + else + bs.buf = file:read(4096) + end + bs.len = bs.buf:len() + return bs +end + +local function hufftable_create(depths) + local nvalues = #depths + local nbits = 1 + local bl_count = {} + local next_code = {} + for i=1,nvalues do + local d = depths[i] + if d > nbits then + nbits = d + end + bl_count[d] = (bl_count[d] or 0) + 1 + end + local table = {} + local code = 0 + bl_count[0] = 0 + for i=1,nbits do + code = (code + (bl_count[i-1] or 0)) * 2 + next_code[i] = code + end + for i=1,nvalues do + local len = depths[i] or 0 + if len > 0 then + local e = (i-1)*16 + len + local code = next_code[len] + local rcode = 0 + for j=1,len do + rcode = rcode + bit.lshift(bit.band(1,bit.rshift(code,j-1)),len-j) + end + for j=0,2^nbits-1,2^len do + table[j+rcode] = e + end + next_code[len] = next_code[len] + 1 + end + end + return table,nbits +end + +local function block_loop(out,bs,nlit,ndist,littable,disttable) + local lit + repeat + lit = bs:getv(littable,nlit) + if lit < 256 then + table.insert(out,lit) + elseif lit > 256 then + local nbits = 0 + local size = 3 + local dist = 1 + if lit < 265 then + size = size + lit - 257 + elseif lit < 285 then + nbits = bit.rshift(lit-261,2) + size = size + bit.lshift(bit.band(lit-261,3)+4,nbits) + else + size = 258 + end + if nbits > 0 then + size = size + bs:getb(nbits) + end + local v = bs:getv(disttable,ndist) + if v < 4 then + dist = dist + v + else + nbits = bit.rshift(v-2,1) + dist = dist + bit.lshift(bit.band(v,1)+2,nbits) + dist = dist + bs:getb(nbits) + end + local p = #out-dist+1 + while size > 0 do + table.insert(out,out[p]) + p = p + 1 + size = size - 1 + end + end + until lit == 256 +end + +local function block_dynamic(out,bs) + local order = { 17, 18, 19, 1, 9, 8, 10, 7, 11, 6, 12, 5, 13, 4, 14, 3, 15, 2, 16 } + local hlit = 257 + bs:getb(5) + local hdist = 1 + bs:getb(5) + local hclen = 4 + bs:getb(4) + local depths = {} + for i=1,hclen do + local v = bs:getb(3) + depths[order[i]] = v + end + for i=hclen+1,19 do + depths[order[i]] = 0 + end + local lengthtable,nlen = hufftable_create(depths) + local i=1 + while i<=hlit+hdist do + local v = bs:getv(lengthtable,nlen) + if v < 16 then + depths[i] = v + i = i + 1 + elseif v < 19 then + local nbt = {2,3,7} + local nb = nbt[v-15] + local c = 0 + local n = 3 + bs:getb(nb) + if v == 16 then + c = depths[i-1] + elseif v == 18 then + n = n + 8 + end + for j=1,n do + depths[i] = c + i = i + 1 + end + else + error("wrong entry in depth table for literal/length alphabet: "..v); + end + end + local litdepths = {} for i=1,hlit do table.insert(litdepths,depths[i]) end + local littable,nlit = hufftable_create(litdepths) + local distdepths = {} for i=hlit+1,#depths do table.insert(distdepths,depths[i]) end + local disttable,ndist = hufftable_create(distdepths) + block_loop(out,bs,nlit,ndist,littable,disttable) +end + +local function block_static(out,bs) + local cnt = { 144, 112, 24, 8 } + local dpt = { 8, 9, 7, 8 } + local depths = {} + for i=1,4 do + local d = dpt[i] + for j=1,cnt[i] do + table.insert(depths,d) + end + end + local littable,nlit = hufftable_create(depths) + depths = {} + for i=1,32 do + depths[i] = 5 + end + local disttable,ndist = hufftable_create(depths) + block_loop(out,bs,nlit,ndist,littable,disttable) +end + +local function block_uncompressed(out,bs) + bs:flushb(bit.band(bs.n,7)) + local len = bs:getb(16) + if bs.n > 0 then + error("Unexpected.. should be zero remaining bits in buffer.") + end + local nlen = bs:getb(16) + if bit.bxor(len,nlen) ~= 65535 then + error("LEN and NLEN don't match") + end + for i=1,len do + table.insert(out,bs:next_byte()) + end +end + +function inflate.main(bs) + local last,type + local output = {} + repeat + local block + last = bs:getb(1) + type = bs:getb(2) + if type == 0 then + block_uncompressed(output,bs) + elseif type == 1 then + block_static(output,bs) + elseif type == 2 then + block_dynamic(output,bs) + else + error("unsupported block type") + end + until last == 1 + bs:flushb(bit.band(bs.n,7)) + return output +end + +local crc32_table +function inflate.crc32(s,crc) + if not crc32_table then + crc32_table = {} + for i=0,255 do + local r=i + for j=1,8 do + r = bit.bxor(bit.rshift(r,1),bit.band(0xedb88320,bit.bnot(bit.band(r,1)-1))) + end + crc32_table[i] = r + end + end + crc = bit.bnot(crc or 0) + for i=1,#s do + local c = s:byte(i) + crc = bit.bxor(crc32_table[bit.bxor(c,bit.band(crc,0xff))],bit.rshift(crc,8)) + end + crc = bit.bnot(crc) + if crc<0 then + -- in Lua < 5.2, sign extension was performed + crc = crc + 4294967296 + end + return crc +end + +return inflate |
