diff --git a/LibDeflate.lua b/LibDeflate.lua
deleted file mode 100644
index b42a107..0000000
--- a/LibDeflate.lua
+++ /dev/null
@@ -1,3466 +0,0 @@
---LibDeflate is originally from here: https://github.com/SafeteeWoW/LibDeflate, it has been edited for only decompression and minified
-
---https://blog.cloudflare.com/improving-compression-with-preset-deflate-dictionary/
-
---[[
-zlib License
-
-(C) 2018-2020 Haoqian He
-
-This software is provided 'as-is', without any express or implied
-warranty. In no event will the authors be held liable for any damages
-arising from the use of this software.
-
-Permission is granted to anyone to use this software for any purpose,
-including commercial applications, and to alter it and redistribute it
-freely, subject to the following restrictions:
-
-1. The origin of this software must not be misrepresented; you must not
- claim that you wrote the original software. If you use this software
- in a product, an acknowledgment in the product documentation would be
- appreciated but is not required.
-2. Altered source versions must be plainly marked as such, and must not be
- misrepresented as being the original software.
-3. This notice may not be removed or altered from any source distribution.
-
-License History:
-1. GNU General Public License Version 3 in v1.0.0 and earlier versions.
-2. GNU Lesser General Public License Version 3 in v1.0.1
-3. the zlib License since v1.0.2
-
-Credits and Disclaimer:
-This library rewrites the code from the algorithm
-and the ideas of the following projects,
-and uses their code to help to test the correctness of this library,
-but their code is not included directly in the library itself.
-Their original licenses shall be comply when used.
-
-1. zlib, by Jean-loup Gailly (compression) and Mark Adler (decompression).
- http://www.zlib.net/
- Licensed under zlib License. http://www.zlib.net/zlib_license.html
- For the compression algorithm.
-2. puff, by Mark Adler. https://github.com/madler/zlib/tree/master/contrib/puff
- Licensed under zlib License. http://www.zlib.net/zlib_license.html
- For the decompression algorithm.
-3. LibCompress, by jjsheets and Galmok of European Stormrage (Horde)
- https://www.wowace.com/projects/libcompress
- Licensed under GPLv2.
- https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
- For the code to create customized codec.
-4. WeakAuras2,
- https://github.com/WeakAuras/WeakAuras2
- Licensed under GPLv2.
- For the 6bit encoding and decoding.
-]]
-
-local LibDeflate
-
-do
- local _VERSION = "1.0.2-release"
-
- local _MAJOR = "LibDeflate"
-
- local _MINOR = 3
-
- local _COPYRIGHT =
- "LibDeflate ".._VERSION
- .." Copyright (C) 2018-2020 Haoqian He."
- .." Licensed under the zlib License"
-
- LibDeflate = {}
-
- LibDeflate._VERSION = _VERSION
- LibDeflate._MAJOR = _MAJOR
- LibDeflate._MINOR = _MINOR
- LibDeflate._COPYRIGHT = _COPYRIGHT
-end
-
--- localize Lua api for faster access.
-local assert = assert
-local error = error
-local pairs = pairs
-local string_byte = string.byte
-local string_char = string.char
-local string_find = string.find
-local string_gsub = string.gsub
-local string_sub = string.sub
-local table_concat = table.concat
-local table_sort = table.sort
-local tostring = tostring
-local type = type
-
--- Converts i to 2^i, (0<=i<=32)
--- This is used to implement bit left shift and bit right shift.
--- "x >> y" in C: "(x-x%_pow2[y])/_pow2[y]" in Lua
--- "x << y" in C: "x*_pow2[y]" in Lua
-local _pow2 = {}
-
--- Converts any byte to a character, (0<=byte<=255)
-local _byte_to_char = {}
-
--- _reverseBitsTbl[len][val] stores the bit reverse of
--- the number with bit length "len" and value "val"
--- For example, decimal number 6 with bits length 5 is binary 00110
--- It's reverse is binary 01100,
--- which is decimal 12 and 12 == _reverseBitsTbl[5][6]
--- 1<=len<=9, 0<=val<=2^len-1
--- The reason for 1<=len<=9 is that the max of min bitlen of huffman code
--- of a huffman alphabet is 9?
-local _reverse_bits_tbl = {}
-
--- Convert a LZ77 length (3<=len<=258) to
--- a deflate literal/LZ77_length code (257<=code<=285)
-local _length_to_deflate_code = {}
-
--- convert a LZ77 length (3<=len<=258) to
--- a deflate literal/LZ77_length code extra bits.
-local _length_to_deflate_extra_bits = {}
-
--- Convert a LZ77 length (3<=len<=258) to
--- a deflate literal/LZ77_length code extra bit length.
-local _length_to_deflate_extra_bitlen = {}
-
--- Convert a small LZ77 distance (1<=dist<=256) to a deflate code.
-local _dist256_to_deflate_code = {}
-
--- Convert a small LZ77 distance (1<=dist<=256) to
--- a deflate distance code extra bits.
-local _dist256_to_deflate_extra_bits = {}
-
--- Convert a small LZ77 distance (1<=dist<=256) to
--- a deflate distance code extra bit length.
-local _dist256_to_deflate_extra_bitlen = {}
-
--- Convert a literal/LZ77_length deflate code to LZ77 base length
--- The key of the table is (code - 256), 257<=code<=285
-local _literal_deflate_code_to_base_len = {
- 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
- 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258,
-}
-
--- Convert a literal/LZ77_length deflate code to base LZ77 length extra bits
--- The key of the table is (code - 256), 257<=code<=285
-local _literal_deflate_code_to_extra_bitlen = {
- 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
- 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0,
-}
-
--- Convert a distance deflate code to base LZ77 distance. (0<=code<=29)
-local _dist_deflate_code_to_base_dist = {
- [0] = 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
- 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
- 8193, 12289, 16385, 24577,
-}
-
--- Convert a distance deflate code to LZ77 bits length. (0<=code<=29)
-local _dist_deflate_code_to_extra_bitlen = {
- [0] = 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
- 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13,
-}
-
--- The code order of the first huffman header in the dynamic deflate block.
--- See the page 12 of RFC1951
-local _rle_codes_huffman_bitlen_order = {16, 17, 18,
- 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15,
-}
-
--- The following tables are used by fixed deflate block.
--- The value of these tables are assigned at the bottom of the source.
-
--- The huffman code of the literal/LZ77_length deflate codes,
--- in fixed deflate block.
-local _fix_block_literal_huffman_code
-
--- Convert huffman code of the literal/LZ77_length to deflate codes,
--- in fixed deflate block.
-local _fix_block_literal_huffman_to_deflate_code
-
--- The bit length of the huffman code of literal/LZ77_length deflate codes,
--- in fixed deflate block.
-local _fix_block_literal_huffman_bitlen
-
--- The count of each bit length of the literal/LZ77_length deflate codes,
--- in fixed deflate block.
-local _fix_block_literal_huffman_bitlen_count
-
--- The huffman code of the distance deflate codes,
--- in fixed deflate block.
-local _fix_block_dist_huffman_code
-
--- Convert huffman code of the distance to deflate codes,
--- in fixed deflate block.
-local _fix_block_dist_huffman_to_deflate_code
-
--- The bit length of the huffman code of the distance deflate codes,
--- in fixed deflate block.
-local _fix_block_dist_huffman_bitlen
-
--- The count of each bit length of the huffman code of
--- the distance deflate codes,
--- in fixed deflate block.
-local _fix_block_dist_huffman_bitlen_count
-
-for i = 0, 255 do
- _byte_to_char[i] = string_char(i)
-end
-
-do
- local pow = 1
- for i = 0, 32 do
- _pow2[i] = pow
- pow = pow * 2
- end
-end
-
-for i = 1, 9 do
- _reverse_bits_tbl[i] = {}
- for j=0, _pow2[i+1]-1 do
- local reverse = 0
- local value = j
- for _ = 1, i do
- -- The following line is equivalent to "res | (code %2)" in C.
- reverse = reverse - reverse%2
- + (((reverse%2==1) or (value % 2) == 1) and 1 or 0)
- value = (value-value%2)/2
- reverse = reverse * 2
- end
- _reverse_bits_tbl[i][j] = (reverse-reverse%2)/2
- end
-end
-
--- The source code is written according to the pattern in the numbers
--- in RFC1951 Page10.
-do
- local a = 18
- local b = 16
- local c = 265
- local bitlen = 1
- for len = 3, 258 do
- if len <= 10 then
- _length_to_deflate_code[len] = len + 254
- _length_to_deflate_extra_bitlen[len] = 0
- elseif len == 258 then
- _length_to_deflate_code[len] = 285
- _length_to_deflate_extra_bitlen[len] = 0
- else
- if len > a then
- a = a + b
- b = b * 2
- c = c + 4
- bitlen = bitlen + 1
- end
- local t = len-a-1+b/2
- _length_to_deflate_code[len] = (t-(t%(b/8)))/(b/8) + c
- _length_to_deflate_extra_bitlen[len] = bitlen
- _length_to_deflate_extra_bits[len] = t % (b/8)
- end
- end
-end
-
--- The source code is written according to the pattern in the numbers
--- in RFC1951 Page11.
-do
- _dist256_to_deflate_code[1] = 0
- _dist256_to_deflate_code[2] = 1
- _dist256_to_deflate_extra_bitlen[1] = 0
- _dist256_to_deflate_extra_bitlen[2] = 0
-
- local a = 3
- local b = 4
- local code = 2
- local bitlen = 0
- for dist = 3, 256 do
- if dist > b then
- a = a * 2
- b = b * 2
- code = code + 2
- bitlen = bitlen + 1
- end
- _dist256_to_deflate_code[dist] = (dist <= a) and code or (code+1)
- _dist256_to_deflate_extra_bitlen[dist] = (bitlen < 0) and 0 or bitlen
- if b >= 8 then
- _dist256_to_deflate_extra_bits[dist] = (dist-b/2-1) % (b/4)
- end
- end
-end
-
---- Calculate the Adler-32 checksum of the string.
--- See RFC1950 Page 9 https://tools.ietf.org/html/rfc1950 for the
--- definition of Adler-32 checksum.
--- @param str [string] the input string to calcuate its Adler-32 checksum.
--- @return [integer] The Adler-32 checksum, which is greater or equal to 0,
--- and less than 2^32 (4294967296).
-function LibDeflate:Adler32(str)
- -- This function is loop unrolled by better performance.
- --
- -- Here is the minimum code:
- --
- -- local a = 1
- -- local b = 0
- -- for i=1, #str do
- -- local s = string.byte(str, i, i)
- -- a = (a+s)%65521
- -- b = (b+a)%65521
- -- end
- -- return b*65536+a
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:Adler32(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- local strlen = #str
-
- local i = 1
- local a = 1
- local b = 0
- while i <= strlen - 15 do
- local x1, x2, x3, x4, x5, x6, x7, x8,
- x9, x10, x11, x12, x13, x14, x15, x16 = string_byte(str, i, i+15)
- b = (b+16*a+16*x1+15*x2+14*x3+13*x4+12*x5+11*x6+10*x7+9*x8+8*x9
- +7*x10+6*x11+5*x12+4*x13+3*x14+2*x15+x16)%65521
- a = (a+x1+x2+x3+x4+x5+x6+x7+x8+x9+x10+x11+x12+x13+x14+x15+x16)%65521
- i = i + 16
- end
- while (i <= strlen) do
- local x = string_byte(str, i, i)
- a = (a + x) % 65521
- b = (b + a) % 65521
- i = i + 1
- end
- return (b*65536+a) % 4294967296
-end
-
--- Compare adler32 checksum.
--- adler32 should be compared with a mod to avoid sign problem
--- 4072834167 (unsigned) is the same adler32 as -222133129
-local function IsEqualAdler32(actual, expected)
- return (actual % 4294967296) == (expected % 4294967296)
-end
-
---- Create a preset dictionary.
---
--- This function is not fast, and the memory consumption of the produced
--- dictionary is about 50 times of the input string. Therefore, it is suggestted
--- to run this function only once in your program.
---
--- It is very important to know that if you do use a preset dictionary,
--- compressors and decompressors MUST USE THE SAME dictionary. That is,
--- dictionary must be created using the same string. If you update your program
--- with a new dictionary, people with the old version won't be able to transmit
--- data with people with the new version. Therefore, changing the dictionary
--- must be very careful.
---
--- The parameters "strlen" and "adler32" add a layer of verification to ensure
--- the parameter "str" is not modified unintentionally during the program
--- development.
---
--- @usage local dict_str = "1234567890"
---
--- -- print(dict_str:len(), LibDeflate:Adler32(dict_str))
--- -- Hardcode the print result below to verify it to avoid acciently
--- -- modification of 'str' during the program development.
--- -- string length: 10, Adler-32: 187433486,
--- -- Don't calculate string length and its Adler-32 at run-time.
---
--- local dict = LibDeflate:CreateDictionary(dict_str, 10, 187433486)
---
--- @param str [string] The string used as the preset dictionary.
--- You should put stuffs that frequently appears in the dictionary
--- string and preferablely put more frequently appeared stuffs toward the end
--- of the string.
--- Empty string and string longer than 32768 bytes are not allowed.
--- @param strlen [integer] The length of 'str'. Please pass in this parameter
--- as a hardcoded constant, in order to verify the content of 'str'. The value
--- of this parameter should be known before your program runs.
--- @param adler32 [integer] The Adler-32 checksum of 'str'. Please pass in this
--- parameter as a hardcoded constant, in order to verify the content of 'str'.
--- The value of this parameter should be known before your program runs.
--- @return [table] The dictionary used for preset dictionary compression and
--- decompression.
--- @raise error if 'strlen' does not match the length of 'str',
--- or if 'adler32' does not match the Adler-32 checksum of 'str'.
-function LibDeflate:CreateDictionary(str, strlen, adler32)
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- if type(strlen) ~= "number" then
- error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
- .." 'strlen' - number expected got '%s'."):format(
- type(strlen)), 2)
- end
- if type(adler32) ~= "number" then
- error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
- .." 'adler32' - number expected got '%s'."):format(
- type(adler32)), 2)
- end
- if strlen ~= #str then
- error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
- .." 'strlen' does not match the actual length of 'str'."
- .." 'strlen': %u, '#str': %u ."
- .." Please check if 'str' is modified unintentionally.")
- :format(strlen, #str))
- end
- if strlen == 0 then
- error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
- .." 'str' - Empty string is not allowed."), 2)
- end
- if strlen > 32768 then
- error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
- .." 'str' - string longer than 32768 bytes is not allowed."
- .." Got %d bytes."):format(strlen), 2)
- end
- local actual_adler32 = self:Adler32(str)
- if not IsEqualAdler32(adler32, actual_adler32) then
- error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
- .." 'adler32' does not match the actual adler32 of 'str'."
- .." 'adler32': %u, 'Adler32(str)': %u ."
- .." Please check if 'str' is modified unintentionally.")
- :format(adler32, actual_adler32))
- end
-
- local dictionary = {}
- dictionary.adler32 = adler32
- dictionary.hash_tables = {}
- dictionary.string_table = {}
- dictionary.strlen = strlen
- local string_table = dictionary.string_table
- local hash_tables = dictionary.hash_tables
- string_table[1] = string_byte(str, 1, 1)
- string_table[2] = string_byte(str, 2, 2)
- if strlen >= 3 then
- local i = 1
- local hash = string_table[1]*256+string_table[2]
- while i <= strlen - 2 - 3 do
- local x1, x2, x3, x4 = string_byte(str, i+2, i+5)
- string_table[i+2] = x1
- string_table[i+3] = x2
- string_table[i+4] = x3
- string_table[i+5] = x4
- hash = (hash*256+x1)%16777216
- local t = hash_tables[hash]
- if not t then t = {}; hash_tables[hash] = t end
- t[#t+1] = i-strlen
- i = i + 1
- hash = (hash*256+x2)%16777216
- t = hash_tables[hash]
- if not t then t = {}; hash_tables[hash] = t end
- t[#t+1] = i-strlen
- i = i + 1
- hash = (hash*256+x3)%16777216
- t = hash_tables[hash]
- if not t then t = {}; hash_tables[hash] = t end
- t[#t+1] = i-strlen
- i = i + 1
- hash = (hash*256+x4)%16777216
- t = hash_tables[hash]
- if not t then t = {}; hash_tables[hash] = t end
- t[#t+1] = i-strlen
- i = i + 1
- end
- while i <= strlen - 2 do
- local x = string_byte(str, i+2)
- string_table[i+2] = x
- hash = (hash*256+x)%16777216
- local t = hash_tables[hash]
- if not t then t = {}; hash_tables[hash] = t end
- t[#t+1] = i-strlen
- i = i + 1
- end
- end
- return dictionary
-end
-
--- Check if the dictionary is valid.
--- @param dictionary The preset dictionary for compression and decompression.
--- @return true if valid, false if not valid.
--- @return if not valid, the error message.
-local function IsValidDictionary(dictionary)
- if type(dictionary) ~= "table" then
- return false, ("'dictionary' - table expected got '%s'.")
- :format(type(dictionary))
- end
- if type(dictionary.adler32) ~= "number"
- or type(dictionary.string_table) ~= "table"
- or type(dictionary.strlen) ~= "number"
- or dictionary.strlen <= 0
- or dictionary.strlen > 32768
- or dictionary.strlen ~= #dictionary.string_table
- or type(dictionary.hash_tables) ~= "table"
- then
- return false, ("'dictionary' - corrupted dictionary.")
- :format(type(dictionary))
- end
- return true, ""
-end
-
---[[
- key of the configuration table is the compression level,
- and its value stores the compression setting.
- These numbers come from zlib source code.
-
- Higher compression level usually means better compression.
- (Because LibDeflate uses a simplified version of zlib algorithm,
- there is no guarantee that higher compression level does not create
- bigger file than lower level, but I can say it's 99% likely)
-
- Be careful with the high compression level. This is a pure lua
- implementation compressor/decompressor, which is significant slower than
- a C/C++ equivalant compressor/decompressor. Very high compression level
- costs significant more CPU time, and usually compression size won't be
- significant smaller when you increase compression level by 1, when the
- level is already very high. Benchmark yourself if you can afford it.
-
- See also https://github.com/madler/zlib/blob/master/doc/algorithm.txt,
- https://github.com/madler/zlib/blob/master/deflate.c for more information.
-
- The meaning of each field:
- @field 1 use_lazy_evaluation:
- true/false. Whether the program uses lazy evaluation.
- See what is "lazy evaluation" in the link above.
- lazy_evaluation improves ratio, but relatively slow.
- @field 2 good_prev_length:
- Only effective if lazy is set, Only use 1/4 of max_chain,
- if prev length of lazy match is above this.
- @field 3 max_insert_length/max_lazy_match:
- If not using lazy evaluation,
- insert new strings in the hash table only if the match length is not
- greater than this length.
- If using lazy evaluation, only continue lazy evaluation,
- if previous match length is strictly smaller than this value.
- @field 4 nice_length:
- Number. Don't continue to go down the hash chain,
- if match length is above this.
- @field 5 max_chain:
- Number. The maximum number of hash chains we look.
---]]
-local _compression_level_configs = {
- [0] = {false, nil, 0, 0, 0}, -- level 0, no compression
- [1] = {false, nil, 4, 8, 4}, -- level 1, similar to zlib level 1
- [2] = {false, nil, 5, 18, 8}, -- level 2, similar to zlib level 2
- [3] = {false, nil, 6, 32, 32}, -- level 3, similar to zlib level 3
- [4] = {true, 4, 4, 16, 16}, -- level 4, similar to zlib level 4
- [5] = {true, 8, 16, 32, 32}, -- level 5, similar to zlib level 5
- [6] = {true, 8, 16, 128, 128}, -- level 6, similar to zlib level 6
- [7] = {true, 8, 32, 128, 256}, -- (SLOW) level 7, similar to zlib level 7
- [8] = {true, 32, 128, 258, 1024} , --(SLOW) level 8,similar to zlib level 8
- [9] = {true, 32, 258, 258, 4096},
- -- (VERY SLOW) level 9, similar to zlib level 9
-}
-
--- Check if the compression/decompression arguments is valid
--- @param str The input string.
--- @param check_dictionary if true, check if dictionary is valid.
--- @param dictionary The preset dictionary for compression and decompression.
--- @param check_configs if true, check if config is valid.
--- @param configs The compression configuration table
--- @return true if valid, false if not valid.
--- @return if not valid, the error message.
-local function IsValidArguments(str,
- check_dictionary, dictionary,
- check_configs, configs)
-
- if type(str) ~= "string" then
- return false,
- ("'str' - string expected got '%s'."):format(type(str))
- end
- if check_dictionary then
- local dict_valid, dict_err = IsValidDictionary(dictionary)
- if not dict_valid then
- return false, dict_err
- end
- end
- if check_configs then
- local type_configs = type(configs)
- if type_configs ~= "nil" and type_configs ~= "table" then
- return false,
- ("'configs' - nil or table expected got '%s'.")
- :format(type(configs))
- end
- if type_configs == "table" then
- for k, v in pairs(configs) do
- if k ~= "level" and k ~= "strategy" then
- return false,
- ("'configs' - unsupported table key in the configs: '%s'.")
- :format(k)
- elseif k == "level" and not _compression_level_configs[v] then
- return false,
- ("'configs' - unsupported 'level': %s."):format(tostring(v))
- elseif k == "strategy" and v ~= "fixed" and v ~= "huffman_only"
- and v ~= "dynamic" then
- -- random_block_type is for testing purpose
- return false, ("'configs' - unsupported 'strategy': '%s'.")
- :format(tostring(v))
- end
- end
- end
- end
- return true, ""
-end
-
-
-
---[[ --------------------------------------------------------------------------
- Compress code
---]] --------------------------------------------------------------------------
-
--- partial flush to save memory
-local _FLUSH_MODE_MEMORY_CLEANUP = 0
--- full flush with partial bytes
-local _FLUSH_MODE_OUTPUT = 1
--- write bytes to get to byte boundary
-local _FLUSH_MODE_BYTE_BOUNDARY = 2
--- no flush, just get num of bits written so far
-local _FLUSH_MODE_NO_FLUSH = 3
-
---[[
- Create an empty writer to easily write stuffs as the unit of bits.
- Return values:
- 1. WriteBits(code, bitlen):
- 2. WriteString(str):
- 3. Flush(mode):
---]]
-local function CreateWriter()
- local buffer_size = 0
- local cache = 0
- local cache_bitlen = 0
- local total_bitlen = 0
- local buffer = {}
- -- When buffer is big enough, flush into result_buffer to save memory.
- local result_buffer = {}
-
- -- Write bits with value "value" and bit length of "bitlen" into writer.
- -- @param value: The value being written
- -- @param bitlen: The bit length of "value"
- -- @return nil
- local function WriteBits(value, bitlen)
- cache = cache + value * _pow2[cache_bitlen]
- cache_bitlen = cache_bitlen + bitlen
- total_bitlen = total_bitlen + bitlen
- -- Only bulk to buffer every 4 bytes. This is quicker.
- if cache_bitlen >= 32 then
- buffer_size = buffer_size + 1
- buffer[buffer_size] =
- _byte_to_char[cache % 256]
- .._byte_to_char[((cache-cache%256)/256 % 256)]
- .._byte_to_char[((cache-cache%65536)/65536 % 256)]
- .._byte_to_char[((cache-cache%16777216)/16777216 % 256)]
- local rshift_mask = _pow2[32 - cache_bitlen + bitlen]
- cache = (value - value%rshift_mask)/rshift_mask
- cache_bitlen = cache_bitlen - 32
- end
- end
-
- -- Write the entire string into the writer.
- -- @param str The string being written
- -- @return nil
- local function WriteString(str)
- for _ = 1, cache_bitlen, 8 do
- buffer_size = buffer_size + 1
- buffer[buffer_size] = string_char(cache % 256)
- cache = (cache-cache%256)/256
- end
- cache_bitlen = 0
- buffer_size = buffer_size + 1
- buffer[buffer_size] = str
- total_bitlen = total_bitlen + #str*8
- end
-
- -- Flush current stuffs in the writer and return it.
- -- This operation will free most of the memory.
- -- @param mode See the descrtion of the constant and the source code.
- -- @return The total number of bits stored in the writer right now.
- -- for byte boundary mode, it includes the padding bits.
- -- for output mode, it does not include padding bits.
- -- @return Return the outputs if mode is output.
- local function FlushWriter(mode)
- if mode == _FLUSH_MODE_NO_FLUSH then
- return total_bitlen
- end
-
- if mode == _FLUSH_MODE_OUTPUT
- or mode == _FLUSH_MODE_BYTE_BOUNDARY then
- -- Full flush, also output cache.
- -- Need to pad some bits if cache_bitlen is not multiple of 8.
- local padding_bitlen = (8 - cache_bitlen % 8) % 8
-
- if cache_bitlen > 0 then
- -- padding with all 1 bits, mainly because "\000" is not
- -- good to be tranmitted. I do this so "\000" is a little bit
- -- less frequent.
- cache = cache - _pow2[cache_bitlen]
- + _pow2[cache_bitlen+padding_bitlen]
- for _ = 1, cache_bitlen, 8 do
- buffer_size = buffer_size + 1
- buffer[buffer_size] = _byte_to_char[cache % 256]
- cache = (cache-cache%256)/256
- end
-
- cache = 0
- cache_bitlen = 0
- end
- if mode == _FLUSH_MODE_BYTE_BOUNDARY then
- total_bitlen = total_bitlen + padding_bitlen
- return total_bitlen
- end
- end
-
- local flushed = table_concat(buffer)
- buffer = {}
- buffer_size = 0
- result_buffer[#result_buffer+1] = flushed
-
- if mode == _FLUSH_MODE_MEMORY_CLEANUP then
- return total_bitlen
- else
- return total_bitlen, table_concat(result_buffer)
- end
- end
-
- return WriteBits, WriteString, FlushWriter
-end
-
--- Push an element into a max heap
--- @param heap A max heap whose max element is at index 1.
--- @param e The element to be pushed. Assume element "e" is a table
--- and comparison is done via its first entry e[1]
--- @param heap_size current number of elements in the heap.
--- NOTE: There may be some garbage stored in
--- heap[heap_size+1], heap[heap_size+2], etc..
--- @return nil
-local function MinHeapPush(heap, e, heap_size)
- heap_size = heap_size + 1
- heap[heap_size] = e
- local value = e[1]
- local pos = heap_size
- local parent_pos = (pos-pos%2)/2
-
- while (parent_pos >= 1 and heap[parent_pos][1] > value) do
- local t = heap[parent_pos]
- heap[parent_pos] = e
- heap[pos] = t
- pos = parent_pos
- parent_pos = (parent_pos-parent_pos%2)/2
- end
-end
-
--- Pop an element from a max heap
--- @param heap A max heap whose max element is at index 1.
--- @param heap_size current number of elements in the heap.
--- @return the poped element
--- Note: This function does not change table size of "heap" to save CPU time.
-local function MinHeapPop(heap, heap_size)
- local top = heap[1]
- local e = heap[heap_size]
- local value = e[1]
- heap[1] = e
- heap[heap_size] = top
- heap_size = heap_size - 1
-
- local pos = 1
- local left_child_pos = pos * 2
- local right_child_pos = left_child_pos + 1
-
- while (left_child_pos <= heap_size) do
- local left_child = heap[left_child_pos]
- if (right_child_pos <= heap_size
- and heap[right_child_pos][1] < left_child[1]) then
- local right_child = heap[right_child_pos]
- if right_child[1] < value then
- heap[right_child_pos] = e
- heap[pos] = right_child
- pos = right_child_pos
- left_child_pos = pos * 2
- right_child_pos = left_child_pos + 1
- else
- break
- end
- else
- if left_child[1] < value then
- heap[left_child_pos] = e
- heap[pos] = left_child
- pos = left_child_pos
- left_child_pos = pos * 2
- right_child_pos = left_child_pos + 1
- else
- break
- end
- end
- end
-
- return top
-end
-
--- Deflate defines a special huffman tree, which is unique once the bit length
--- of huffman code of all symbols are known.
--- @param bitlen_count Number of symbols with a specific bitlen
--- @param symbol_bitlen The bit length of a symbol
--- @param max_symbol The max symbol among all symbols,
--- which is (number of symbols - 1)
--- @param max_bitlen The max huffman bit length among all symbols.
--- @return The huffman code of all symbols.
-local function GetHuffmanCodeFromBitlen(bitlen_counts, symbol_bitlens
- , max_symbol, max_bitlen)
- local huffman_code = 0
- local next_codes = {}
- local symbol_huffman_codes = {}
- for bitlen = 1, max_bitlen do
- huffman_code = (huffman_code+(bitlen_counts[bitlen-1] or 0))*2
- next_codes[bitlen] = huffman_code
- end
- for symbol = 0, max_symbol do
- local bitlen = symbol_bitlens[symbol]
- if bitlen then
- huffman_code = next_codes[bitlen]
- next_codes[bitlen] = huffman_code + 1
-
- -- Reverse the bits of huffman code,
- -- because most signifant bits of huffman code
- -- is stored first into the compressed data.
- -- @see RFC1951 Page5 Section 3.1.1
- if bitlen <= 9 then -- Have cached reverse for small bitlen.
- symbol_huffman_codes[symbol] =
- _reverse_bits_tbl[bitlen][huffman_code]
- else
- local reverse = 0
- for _ = 1, bitlen do
- reverse = reverse - reverse%2
- + (((reverse%2==1)
- or (huffman_code % 2) == 1) and 1 or 0)
- huffman_code = (huffman_code-huffman_code%2)/2
- reverse = reverse*2
- end
- symbol_huffman_codes[symbol] = (reverse-reverse%2)/2
- end
- end
- end
- return symbol_huffman_codes
-end
-
--- A helper function to sort heap elements
--- a[1], b[1] is the huffman frequency
--- a[2], b[2] is the symbol value.
-local function SortByFirstThenSecond(a, b)
- return a[1] < b[1] or
- (a[1] == b[1] and a[2] < b[2])
-end
-
--- Calculate the huffman bit length and huffman code.
--- @param symbol_count: A table whose table key is the symbol, and table value
--- is the symbol frenquency (nil means 0 frequency).
--- @param max_bitlen: See description of return value.
--- @param max_symbol: The maximum symbol
--- @return a table whose key is the symbol, and the value is the huffman bit
--- bit length. We guarantee that all bit length <= max_bitlen.
--- For 0<=symbol<=max_symbol, table value could be nil if the frequency
--- of the symbol is 0 or nil.
--- @return a table whose key is the symbol, and the value is the huffman code.
--- @return a number indicating the maximum symbol whose bitlen is not 0.
-local function GetHuffmanBitlenAndCode(symbol_counts, max_bitlen, max_symbol)
- local heap_size
- local max_non_zero_bitlen_symbol = -1
- local leafs = {}
- local heap = {}
- local symbol_bitlens = {}
- local symbol_codes = {}
- local bitlen_counts = {}
-
- --[[
- tree[1]: weight, temporarily used as parent and bitLengths
- tree[2]: symbol
- tree[3]: left child
- tree[4]: right child
- --]]
- local number_unique_symbols = 0
- for symbol, count in pairs(symbol_counts) do
- number_unique_symbols = number_unique_symbols + 1
- leafs[number_unique_symbols] = {count, symbol}
- end
-
- if (number_unique_symbols == 0) then
- -- no code.
- return {}, {}, -1
- elseif (number_unique_symbols == 1) then
- -- Only one code. In this case, its huffman code
- -- needs to be assigned as 0, and bit length is 1.
- -- This is the only case that the return result
- -- represents an imcomplete huffman tree.
- local symbol = leafs[1][2]
- symbol_bitlens[symbol] = 1
- symbol_codes[symbol] = 0
- return symbol_bitlens, symbol_codes, symbol
- else
- table_sort(leafs, SortByFirstThenSecond)
- heap_size = number_unique_symbols
- for i = 1, heap_size do
- heap[i] = leafs[i]
- end
-
- while (heap_size > 1) do
- -- Note: pop does not change table size of heap
- local leftChild = MinHeapPop(heap, heap_size)
- heap_size = heap_size - 1
- local rightChild = MinHeapPop(heap, heap_size)
- heap_size = heap_size - 1
- local newNode =
- {leftChild[1]+rightChild[1], -1, leftChild, rightChild}
- MinHeapPush(heap, newNode, heap_size)
- heap_size = heap_size + 1
- end
-
- -- Number of leafs whose bit length is greater than max_len.
- local number_bitlen_overflow = 0
-
- -- Calculate bit length of all nodes
- local fifo = {heap[1], 0, 0, 0} -- preallocate some spaces.
- local fifo_size = 1
- local index = 1
- heap[1][1] = 0
- while (index <= fifo_size) do -- Breath first search
- local e = fifo[index]
- local bitlen = e[1]
- local symbol = e[2]
- local left_child = e[3]
- local right_child = e[4]
- if left_child then
- fifo_size = fifo_size + 1
- fifo[fifo_size] = left_child
- left_child[1] = bitlen + 1
- end
- if right_child then
- fifo_size = fifo_size + 1
- fifo[fifo_size] = right_child
- right_child[1] = bitlen + 1
- end
- index = index + 1
-
- if (bitlen > max_bitlen) then
- number_bitlen_overflow = number_bitlen_overflow + 1
- bitlen = max_bitlen
- end
- if symbol >= 0 then
- symbol_bitlens[symbol] = bitlen
- max_non_zero_bitlen_symbol =
- (symbol > max_non_zero_bitlen_symbol)
- and symbol or max_non_zero_bitlen_symbol
- bitlen_counts[bitlen] = (bitlen_counts[bitlen] or 0) + 1
- end
- end
-
- -- Resolve bit length overflow
- -- @see ZLib/trees.c:gen_bitlen(s, desc), for reference
- if (number_bitlen_overflow > 0) then
- repeat
- local bitlen = max_bitlen - 1
- while ((bitlen_counts[bitlen] or 0) == 0) do
- bitlen = bitlen - 1
- end
- -- move one leaf down the tree
- bitlen_counts[bitlen] = bitlen_counts[bitlen] - 1
- -- move one overflow item as its brother
- bitlen_counts[bitlen+1] = (bitlen_counts[bitlen+1] or 0) + 2
- bitlen_counts[max_bitlen] = bitlen_counts[max_bitlen] - 1
- number_bitlen_overflow = number_bitlen_overflow - 2
- until (number_bitlen_overflow <= 0)
-
- index = 1
- for bitlen = max_bitlen, 1, -1 do
- local n = bitlen_counts[bitlen] or 0
- while (n > 0) do
- local symbol = leafs[index][2]
- symbol_bitlens[symbol] = bitlen
- n = n - 1
- index = index + 1
- end
- end
- end
-
- symbol_codes = GetHuffmanCodeFromBitlen(bitlen_counts, symbol_bitlens,
- max_symbol, max_bitlen)
- return symbol_bitlens, symbol_codes, max_non_zero_bitlen_symbol
- end
-end
-
--- Calculate the first huffman header in the dynamic huffman block
--- @see RFC1951 Page 12
--- @param lcode_bitlen: The huffman bit length of literal/LZ77_length.
--- @param max_non_zero_bitlen_lcode: The maximum literal/LZ77_length symbol
--- whose huffman bit length is not zero.
--- @param dcode_bitlen: The huffman bit length of LZ77 distance.
--- @param max_non_zero_bitlen_dcode: The maximum LZ77 distance symbol
--- whose huffman bit length is not zero.
--- @return The run length encoded codes.
--- @return The extra bits. One entry for each rle code that needs extra bits.
--- (code == 16 or 17 or 18).
--- @return The count of appearance of each rle codes.
-local function RunLengthEncodeHuffmanBitlen(
- lcode_bitlens,
- max_non_zero_bitlen_lcode,
- dcode_bitlens,
- max_non_zero_bitlen_dcode)
- local rle_code_tblsize = 0
- local rle_codes = {}
- local rle_code_counts = {}
- local rle_extra_bits_tblsize = 0
- local rle_extra_bits = {}
- local prev = nil
- local count = 0
-
- -- If there is no distance code, assume one distance code of bit length 0.
- -- RFC1951: One distance code of zero bits means that
- -- there are no distance codes used at all (the data is all literals).
- max_non_zero_bitlen_dcode = (max_non_zero_bitlen_dcode < 0)
- and 0 or max_non_zero_bitlen_dcode
- local max_code = max_non_zero_bitlen_lcode+max_non_zero_bitlen_dcode+1
-
- for code = 0, max_code+1 do
- local len = (code <= max_non_zero_bitlen_lcode)
- and (lcode_bitlens[code] or 0)
- or ((code <= max_code)
- and (dcode_bitlens[code-max_non_zero_bitlen_lcode-1] or 0) or nil)
- if len == prev then
- count = count + 1
- if len ~= 0 and count == 6 then
- rle_code_tblsize = rle_code_tblsize + 1
- rle_codes[rle_code_tblsize] = 16
- rle_extra_bits_tblsize = rle_extra_bits_tblsize + 1
- rle_extra_bits[rle_extra_bits_tblsize] = 3
- rle_code_counts[16] = (rle_code_counts[16] or 0) + 1
- count = 0
- elseif len == 0 and count == 138 then
- rle_code_tblsize = rle_code_tblsize + 1
- rle_codes[rle_code_tblsize] = 18
- rle_extra_bits_tblsize = rle_extra_bits_tblsize + 1
- rle_extra_bits[rle_extra_bits_tblsize] = 127
- rle_code_counts[18] = (rle_code_counts[18] or 0) + 1
- count = 0
- end
- else
- if count == 1 then
- rle_code_tblsize = rle_code_tblsize + 1
- rle_codes[rle_code_tblsize] = prev
- rle_code_counts[prev] = (rle_code_counts[prev] or 0) + 1
- elseif count == 2 then
- rle_code_tblsize = rle_code_tblsize + 1
- rle_codes[rle_code_tblsize] = prev
- rle_code_tblsize = rle_code_tblsize + 1
- rle_codes[rle_code_tblsize] = prev
- rle_code_counts[prev] = (rle_code_counts[prev] or 0) + 2
- elseif count >= 3 then
- rle_code_tblsize = rle_code_tblsize + 1
- local rleCode = (prev ~= 0) and 16 or (count <= 10 and 17 or 18)
- rle_codes[rle_code_tblsize] = rleCode
- rle_code_counts[rleCode] = (rle_code_counts[rleCode] or 0) + 1
- rle_extra_bits_tblsize = rle_extra_bits_tblsize + 1
- rle_extra_bits[rle_extra_bits_tblsize] =
- (count <= 10) and (count - 3) or (count - 11)
- end
-
- prev = len
- if len and len ~= 0 then
- rle_code_tblsize = rle_code_tblsize + 1
- rle_codes[rle_code_tblsize] = len
- rle_code_counts[len] = (rle_code_counts[len] or 0) + 1
- count = 0
- else
- count = 1
- end
- end
- end
-
- return rle_codes, rle_extra_bits, rle_code_counts
-end
-
--- Load the string into a table, in order to speed up LZ77.
--- Loop unrolled 16 times to speed this function up.
--- @param str The string to be loaded.
--- @param t The load destination
--- @param start str[index] will be the first character to be loaded.
--- @param end str[index] will be the last character to be loaded
--- @param offset str[index] will be loaded into t[index-offset]
--- @return t
-local function LoadStringToTable(str, t, start, stop, offset)
- local i = start - offset
- while i <= stop - 15 - offset do
- t[i], t[i+1], t[i+2], t[i+3], t[i+4], t[i+5], t[i+6], t[i+7], t[i+8],
- t[i+9], t[i+10], t[i+11], t[i+12], t[i+13], t[i+14], t[i+15] =
- string_byte(str, i + offset, i + 15 + offset)
- i = i + 16
- end
- while (i <= stop - offset) do
- t[i] = string_byte(str, i + offset, i + offset)
- i = i + 1
- end
- return t
-end
-
--- Do LZ77 process. This function uses the majority of the CPU time.
--- @see zlib/deflate.c:deflate_fast(), zlib/deflate.c:deflate_slow()
--- @see https://github.com/madler/zlib/blob/master/doc/algorithm.txt
--- This function uses the algorithms used above. You should read the
--- algorithm.txt above to understand what is the hash function and the
--- lazy evaluation.
---
--- The special optimization used here is hash functions used here.
--- The hash function is just the multiplication of the three consective
--- characters. So if the hash matches, it guarantees 3 characters are matched.
--- This optimization can be implemented because Lua table is a hash table.
---
--- @param level integer that describes compression level.
--- @param string_table table that stores the value of string to be compressed.
--- The index of this table starts from 1.
--- The caller needs to make sure all values needed by this function
--- are loaded.
--- Assume "str" is the origin input string into the compressor
--- str[block_start]..str[block_end+3] needs to be loaded into
--- string_table[block_start-offset]..string_table[block_end-offset]
--- If dictionary is presented, the last 258 bytes of the dictionary
--- needs to be loaded into sing_table[-257..0]
--- (See more in the description of offset.)
--- @param hash_tables. The table key is the hash value (0<=hash<=16777216=256^3)
--- The table value is an array0 that stores the indexes of the
--- input data string to be compressed, such that
--- hash == str[index]*str[index+1]*str[index+2]
--- Indexes are ordered in this array.
--- @param block_start The indexes of the input data string to be compressed.
--- that starts the LZ77 block.
--- @param block_end The indexes of the input data string to be compressed.
--- that stores the LZ77 block.
--- @param offset str[index] is stored in string_table[index-offset],
--- This offset is mainly an optimization to limit the index
--- of string_table, so lua can access this table quicker.
--- @param dictionary See LibDeflate:CreateDictionary
--- @return literal/LZ77_length deflate codes.
--- @return the extra bits of literal/LZ77_length deflate codes.
--- @return the count of each literal/LZ77 deflate code.
--- @return LZ77 distance deflate codes.
--- @return the extra bits of LZ77 distance deflate codes.
--- @return the count of each LZ77 distance deflate code.
-local function GetBlockLZ77Result(level, string_table, hash_tables, block_start,
- block_end, offset, dictionary)
- local config = _compression_level_configs[level]
- local config_use_lazy
- , config_good_prev_length
- , config_max_lazy_match
- , config_nice_length
- , config_max_hash_chain =
- config[1], config[2], config[3], config[4], config[5]
-
- local config_max_insert_length = (not config_use_lazy)
- and config_max_lazy_match or 2147483646
- local config_good_hash_chain =
- (config_max_hash_chain-config_max_hash_chain%4/4)
-
- local hash
-
- local dict_hash_tables
- local dict_string_table
- local dict_string_len = 0
-
- if dictionary then
- dict_hash_tables = dictionary.hash_tables
- dict_string_table = dictionary.string_table
- dict_string_len = dictionary.strlen
- assert(block_start == 1)
- if block_end >= block_start and dict_string_len >= 2 then
- hash = dict_string_table[dict_string_len-1]*65536
- + dict_string_table[dict_string_len]*256 + string_table[1]
- local t = hash_tables[hash]
- if not t then t = {}; hash_tables[hash] = t end
- t[#t+1] = -1
- end
- if block_end >= block_start+1 and dict_string_len >= 1 then
- hash = dict_string_table[dict_string_len]*65536
- + string_table[1]*256 + string_table[2]
- local t = hash_tables[hash]
- if not t then t = {}; hash_tables[hash] = t end
- t[#t+1] = 0
- end
- end
-
- local dict_string_len_plus3 = dict_string_len + 3
-
- hash = (string_table[block_start-offset] or 0)*256
- + (string_table[block_start+1-offset] or 0)
-
- local lcodes = {}
- local lcode_tblsize = 0
- local lcodes_counts = {}
- local dcodes = {}
- local dcodes_tblsize = 0
- local dcodes_counts = {}
-
- local lextra_bits = {}
- local lextra_bits_tblsize = 0
- local dextra_bits = {}
- local dextra_bits_tblsize = 0
-
- local match_available = false
- local prev_len
- local prev_dist
- local cur_len = 0
- local cur_dist = 0
-
- local index = block_start
- local index_end = block_end + (config_use_lazy and 1 or 0)
-
- -- the zlib source code writes separate code for lazy evaluation and
- -- not lazy evaluation, which is easier to understand.
- -- I put them together, so it is a bit harder to understand.
- -- because I think this is easier for me to maintain it.
- while (index <= index_end) do
- local string_table_index = index - offset
- local offset_minus_three = offset - 3
- prev_len = cur_len
- prev_dist = cur_dist
- cur_len = 0
-
- hash = (hash*256+(string_table[string_table_index+2] or 0))%16777216
-
- local chain_index
- local cur_chain
- local hash_chain = hash_tables[hash]
- local chain_old_size
- if not hash_chain then
- chain_old_size = 0
- hash_chain = {}
- hash_tables[hash] = hash_chain
- if dict_hash_tables then
- cur_chain = dict_hash_tables[hash]
- chain_index = cur_chain and #cur_chain or 0
- else
- chain_index = 0
- end
- else
- chain_old_size = #hash_chain
- cur_chain = hash_chain
- chain_index = chain_old_size
- end
-
- if index <= block_end then
- hash_chain[chain_old_size+1] = index
- end
-
- if (chain_index > 0 and index + 2 <= block_end
- and (not config_use_lazy or prev_len < config_max_lazy_match)) then
-
- local depth =
- (config_use_lazy and prev_len >= config_good_prev_length)
- and config_good_hash_chain or config_max_hash_chain
-
- local max_len_minus_one = block_end - index
- max_len_minus_one = (max_len_minus_one >= 257) and 257 or max_len_minus_one
- max_len_minus_one = max_len_minus_one + string_table_index
- local string_table_index_plus_three = string_table_index + 3
-
- while chain_index >= 1 and depth > 0 do
- local prev = cur_chain[chain_index]
-
- if index - prev > 32768 then
- break
- end
- if prev < index then
- local sj = string_table_index_plus_three
-
- if prev >= -257 then
- local pj = prev - offset_minus_three
- while (sj <= max_len_minus_one
- and string_table[pj]
- == string_table[sj]) do
- sj = sj + 1
- pj = pj + 1
- end
- else
- local pj = dict_string_len_plus3 + prev
- while (sj <= max_len_minus_one
- and dict_string_table[pj]
- == string_table[sj]) do
- sj = sj + 1
- pj = pj + 1
- end
- end
- local j = sj - string_table_index
- if j > cur_len then
- cur_len = j
- cur_dist = index - prev
- end
- if cur_len >= config_nice_length then
- break
- end
- end
-
- chain_index = chain_index - 1
- depth = depth - 1
- if chain_index == 0 and prev > 0 and dict_hash_tables then
- cur_chain = dict_hash_tables[hash]
- chain_index = cur_chain and #cur_chain or 0
- end
- end
- end
-
- if not config_use_lazy then
- prev_len, prev_dist = cur_len, cur_dist
- end
- if ((not config_use_lazy or match_available)
- and (prev_len > 3 or (prev_len == 3 and prev_dist < 4096))
- and cur_len <= prev_len )then
- local code = _length_to_deflate_code[prev_len]
- local length_extra_bits_bitlen =
- _length_to_deflate_extra_bitlen[prev_len]
- local dist_code, dist_extra_bits_bitlen, dist_extra_bits
- if prev_dist <= 256 then -- have cached code for small distance.
- dist_code = _dist256_to_deflate_code[prev_dist]
- dist_extra_bits = _dist256_to_deflate_extra_bits[prev_dist]
- dist_extra_bits_bitlen =
- _dist256_to_deflate_extra_bitlen[prev_dist]
- else
- dist_code = 16
- dist_extra_bits_bitlen = 7
- local a = 384
- local b = 512
-
- while true do
- if prev_dist <= a then
- dist_extra_bits = (prev_dist-(b/2)-1) % (b/4)
- break
- elseif prev_dist <= b then
- dist_extra_bits = (prev_dist-(b/2)-1) % (b/4)
- dist_code = dist_code + 1
- break
- else
- dist_code = dist_code + 2
- dist_extra_bits_bitlen = dist_extra_bits_bitlen + 1
- a = a*2
- b = b*2
- end
- end
- end
- lcode_tblsize = lcode_tblsize + 1
- lcodes[lcode_tblsize] = code
- lcodes_counts[code] = (lcodes_counts[code] or 0) + 1
-
- dcodes_tblsize = dcodes_tblsize + 1
- dcodes[dcodes_tblsize] = dist_code
- dcodes_counts[dist_code] = (dcodes_counts[dist_code] or 0) + 1
-
- if length_extra_bits_bitlen > 0 then
- local lenExtraBits = _length_to_deflate_extra_bits[prev_len]
- lextra_bits_tblsize = lextra_bits_tblsize + 1
- lextra_bits[lextra_bits_tblsize] = lenExtraBits
- end
- if dist_extra_bits_bitlen > 0 then
- dextra_bits_tblsize = dextra_bits_tblsize + 1
- dextra_bits[dextra_bits_tblsize] = dist_extra_bits
- end
-
- for i=index+1, index+prev_len-(config_use_lazy and 2 or 1) do
- hash = (hash*256+(string_table[i-offset+2] or 0))%16777216
- if prev_len <= config_max_insert_length then
- hash_chain = hash_tables[hash]
- if not hash_chain then
- hash_chain = {}
- hash_tables[hash] = hash_chain
- end
- hash_chain[#hash_chain+1] = i
- end
- end
- index = index + prev_len - (config_use_lazy and 1 or 0)
- match_available = false
- elseif (not config_use_lazy) or match_available then
- local code = string_table[config_use_lazy
- and (string_table_index-1) or string_table_index]
- lcode_tblsize = lcode_tblsize + 1
- lcodes[lcode_tblsize] = code
- lcodes_counts[code] = (lcodes_counts[code] or 0) + 1
- index = index + 1
- else
- match_available = true
- index = index + 1
- end
- end
-
- -- Write "end of block" symbol
- lcode_tblsize = lcode_tblsize + 1
- lcodes[lcode_tblsize] = 256
- lcodes_counts[256] = (lcodes_counts[256] or 0) + 1
-
- return lcodes, lextra_bits, lcodes_counts, dcodes, dextra_bits
- , dcodes_counts
-end
-
--- Get the header data of dynamic block.
--- @param lcodes_count The count of each literal/LZ77_length codes.
--- @param dcodes_count The count of each Lz77 distance codes.
--- @return a lots of stuffs.
--- @see RFC1951 Page 12
-local function GetBlockDynamicHuffmanHeader(lcodes_counts, dcodes_counts)
- local lcodes_huffman_bitlens, lcodes_huffman_codes
- , max_non_zero_bitlen_lcode =
- GetHuffmanBitlenAndCode(lcodes_counts, 15, 285)
- local dcodes_huffman_bitlens, dcodes_huffman_codes
- , max_non_zero_bitlen_dcode =
- GetHuffmanBitlenAndCode(dcodes_counts, 15, 29)
-
- local rle_deflate_codes, rle_extra_bits, rle_codes_counts =
- RunLengthEncodeHuffmanBitlen(lcodes_huffman_bitlens
- ,max_non_zero_bitlen_lcode, dcodes_huffman_bitlens
- , max_non_zero_bitlen_dcode)
-
- local rle_codes_huffman_bitlens, rle_codes_huffman_codes =
- GetHuffmanBitlenAndCode(rle_codes_counts, 7, 18)
-
- local HCLEN = 0
- for i = 1, 19 do
- local symbol = _rle_codes_huffman_bitlen_order[i]
- local length = rle_codes_huffman_bitlens[symbol] or 0
- if length ~= 0 then
- HCLEN = i
- end
- end
-
- HCLEN = HCLEN - 4
- local HLIT = max_non_zero_bitlen_lcode + 1 - 257
- local HDIST = max_non_zero_bitlen_dcode + 1 - 1
- if HDIST < 0 then HDIST = 0 end
-
- return HLIT, HDIST, HCLEN, rle_codes_huffman_bitlens
- , rle_codes_huffman_codes, rle_deflate_codes, rle_extra_bits
- , lcodes_huffman_bitlens, lcodes_huffman_codes
- , dcodes_huffman_bitlens, dcodes_huffman_codes
-end
-
--- Get the size of dynamic block without writing any bits into the writer.
--- @param ... Read the source code of GetBlockDynamicHuffmanHeader()
--- @return the bit length of the dynamic block
-local function GetDynamicHuffmanBlockSize(lcodes, dcodes, HCLEN
- , rle_codes_huffman_bitlens, rle_deflate_codes
- , lcodes_huffman_bitlens, dcodes_huffman_bitlens)
-
- local block_bitlen = 17 -- 1+2+5+5+4
- block_bitlen = block_bitlen + (HCLEN+4)*3
-
- for i = 1, #rle_deflate_codes do
- local code = rle_deflate_codes[i]
- block_bitlen = block_bitlen + rle_codes_huffman_bitlens[code]
- if code >= 16 then
- block_bitlen = block_bitlen +
- ((code == 16) and 2 or (code == 17 and 3 or 7))
- end
- end
-
- local length_code_count = 0
- for i = 1, #lcodes do
- local code = lcodes[i]
- local huffman_bitlen = lcodes_huffman_bitlens[code]
- block_bitlen = block_bitlen + huffman_bitlen
- if code > 256 then -- Length code
- length_code_count = length_code_count + 1
- if code > 264 and code < 285 then -- Length code with extra bits
- local extra_bits_bitlen =
- _literal_deflate_code_to_extra_bitlen[code-256]
- block_bitlen = block_bitlen + extra_bits_bitlen
- end
- local dist_code = dcodes[length_code_count]
- local dist_huffman_bitlen = dcodes_huffman_bitlens[dist_code]
- block_bitlen = block_bitlen + dist_huffman_bitlen
-
- if dist_code > 3 then -- dist code with extra bits
- local dist_extra_bits_bitlen = (dist_code-dist_code%2)/2 - 1
- block_bitlen = block_bitlen + dist_extra_bits_bitlen
- end
- end
- end
- return block_bitlen
-end
-
--- Write dynamic block.
--- @param ... Read the source code of GetBlockDynamicHuffmanHeader()
-local function CompressDynamicHuffmanBlock(WriteBits, is_last_block
- , lcodes, lextra_bits, dcodes, dextra_bits, HLIT, HDIST, HCLEN
- , rle_codes_huffman_bitlens, rle_codes_huffman_codes
- , rle_deflate_codes, rle_extra_bits
- , lcodes_huffman_bitlens, lcodes_huffman_codes
- , dcodes_huffman_bitlens, dcodes_huffman_codes)
-
- WriteBits(is_last_block and 1 or 0, 1) -- Last block identifier
- WriteBits(2, 2) -- Dynamic Huffman block identifier
-
- WriteBits(HLIT, 5)
- WriteBits(HDIST, 5)
- WriteBits(HCLEN, 4)
-
- for i = 1, HCLEN+4 do
- local symbol = _rle_codes_huffman_bitlen_order[i]
- local length = rle_codes_huffman_bitlens[symbol] or 0
- WriteBits(length, 3)
- end
-
- local rleExtraBitsIndex = 1
- for i=1, #rle_deflate_codes do
- local code = rle_deflate_codes[i]
- WriteBits(rle_codes_huffman_codes[code]
- , rle_codes_huffman_bitlens[code])
- if code >= 16 then
- local extraBits = rle_extra_bits[rleExtraBitsIndex]
- WriteBits(extraBits, (code == 16) and 2 or (code == 17 and 3 or 7))
- rleExtraBitsIndex = rleExtraBitsIndex + 1
- end
- end
-
- local length_code_count = 0
- local length_code_with_extra_count = 0
- local dist_code_with_extra_count = 0
-
- for i=1, #lcodes do
- local deflate_codee = lcodes[i]
- local huffman_code = lcodes_huffman_codes[deflate_codee]
- local huffman_bitlen = lcodes_huffman_bitlens[deflate_codee]
- WriteBits(huffman_code, huffman_bitlen)
- if deflate_codee > 256 then -- Length code
- length_code_count = length_code_count + 1
- if deflate_codee > 264 and deflate_codee < 285 then
- -- Length code with extra bits
- length_code_with_extra_count = length_code_with_extra_count + 1
- local extra_bits = lextra_bits[length_code_with_extra_count]
- local extra_bits_bitlen =
- _literal_deflate_code_to_extra_bitlen[deflate_codee-256]
- WriteBits(extra_bits, extra_bits_bitlen)
- end
- -- Write distance code
- local dist_deflate_code = dcodes[length_code_count]
- local dist_huffman_code = dcodes_huffman_codes[dist_deflate_code]
- local dist_huffman_bitlen =
- dcodes_huffman_bitlens[dist_deflate_code]
- WriteBits(dist_huffman_code, dist_huffman_bitlen)
-
- if dist_deflate_code > 3 then -- dist code with extra bits
- dist_code_with_extra_count = dist_code_with_extra_count + 1
- local dist_extra_bits = dextra_bits[dist_code_with_extra_count]
- local dist_extra_bits_bitlen =
- (dist_deflate_code-dist_deflate_code%2)/2 - 1
- WriteBits(dist_extra_bits, dist_extra_bits_bitlen)
- end
- end
- end
-end
-
--- Get the size of fixed block without writing any bits into the writer.
--- @param lcodes literal/LZ77_length deflate codes
--- @param decodes LZ77 distance deflate codes
--- @return the bit length of the fixed block
-local function GetFixedHuffmanBlockSize(lcodes, dcodes)
- local block_bitlen = 3
- local length_code_count = 0
- for i=1, #lcodes do
- local code = lcodes[i]
- local huffman_bitlen = _fix_block_literal_huffman_bitlen[code]
- block_bitlen = block_bitlen + huffman_bitlen
- if code > 256 then -- Length code
- length_code_count = length_code_count + 1
- if code > 264 and code < 285 then -- Length code with extra bits
- local extra_bits_bitlen =
- _literal_deflate_code_to_extra_bitlen[code-256]
- block_bitlen = block_bitlen + extra_bits_bitlen
- end
- local dist_code = dcodes[length_code_count]
- block_bitlen = block_bitlen + 5
-
- if dist_code > 3 then -- dist code with extra bits
- local dist_extra_bits_bitlen =
- (dist_code-dist_code%2)/2 - 1
- block_bitlen = block_bitlen + dist_extra_bits_bitlen
- end
- end
- end
- return block_bitlen
-end
-
--- Write fixed block.
--- @param lcodes literal/LZ77_length deflate codes
--- @param decodes LZ77 distance deflate codes
-local function CompressFixedHuffmanBlock(WriteBits, is_last_block,
- lcodes, lextra_bits, dcodes, dextra_bits)
- WriteBits(is_last_block and 1 or 0, 1) -- Last block identifier
- WriteBits(1, 2) -- Fixed Huffman block identifier
- local length_code_count = 0
- local length_code_with_extra_count = 0
- local dist_code_with_extra_count = 0
- for i=1, #lcodes do
- local deflate_code = lcodes[i]
- local huffman_code = _fix_block_literal_huffman_code[deflate_code]
- local huffman_bitlen = _fix_block_literal_huffman_bitlen[deflate_code]
- WriteBits(huffman_code, huffman_bitlen)
- if deflate_code > 256 then -- Length code
- length_code_count = length_code_count + 1
- if deflate_code > 264 and deflate_code < 285 then
- -- Length code with extra bits
- length_code_with_extra_count = length_code_with_extra_count + 1
- local extra_bits = lextra_bits[length_code_with_extra_count]
- local extra_bits_bitlen =
- _literal_deflate_code_to_extra_bitlen[deflate_code-256]
- WriteBits(extra_bits, extra_bits_bitlen)
- end
- -- Write distance code
- local dist_code = dcodes[length_code_count]
- local dist_huffman_code = _fix_block_dist_huffman_code[dist_code]
- WriteBits(dist_huffman_code, 5)
-
- if dist_code > 3 then -- dist code with extra bits
- dist_code_with_extra_count = dist_code_with_extra_count + 1
- local dist_extra_bits = dextra_bits[dist_code_with_extra_count]
- local dist_extra_bits_bitlen = (dist_code-dist_code%2)/2 - 1
- WriteBits(dist_extra_bits, dist_extra_bits_bitlen)
- end
- end
- end
-end
-
--- Get the size of store block without writing any bits into the writer.
--- @param block_start The start index of the origin input string
--- @param block_end The end index of the origin input string
--- @param Total bit lens had been written into the compressed result before,
--- because store block needs to shift to byte boundary.
--- @return the bit length of the fixed block
-local function GetStoreBlockSize(block_start, block_end, total_bitlen)
- assert(block_end-block_start+1 <= 65535)
- local block_bitlen = 3
- total_bitlen = total_bitlen + 3
- local padding_bitlen = (8-total_bitlen%8)%8
- block_bitlen = block_bitlen + padding_bitlen
- block_bitlen = block_bitlen + 32
- block_bitlen = block_bitlen + (block_end - block_start + 1) * 8
- return block_bitlen
-end
-
--- Write the store block.
--- @param ... lots of stuffs
--- @return nil
-local function CompressStoreBlock(WriteBits, WriteString, is_last_block, str
- , block_start, block_end, total_bitlen)
- assert(block_end-block_start+1 <= 65535)
- WriteBits(is_last_block and 1 or 0, 1) -- Last block identifer.
- WriteBits(0, 2) -- Store block identifier.
- total_bitlen = total_bitlen + 3
- local padding_bitlen = (8-total_bitlen%8)%8
- if padding_bitlen > 0 then
- WriteBits(_pow2[padding_bitlen]-1, padding_bitlen)
- end
- local size = block_end - block_start + 1
- WriteBits(size, 16)
-
- -- Write size's one's complement
- local comp = (255 - size % 256) + (255 - (size-size%256)/256)*256
- WriteBits(comp, 16)
-
- WriteString(str:sub(block_start, block_end))
-end
-
--- Do the deflate
--- Currently using a simple way to determine the block size
--- (This is why the compression ratio is little bit worse than zlib when
--- the input size is very large
--- The first block is 64KB, the following block is 32KB.
--- After each block, there is a memory cleanup operation.
--- This is not a fast operation, but it is needed to save memory usage, so
--- the memory usage does not grow unboundly. If the data size is less than
--- 64KB, then memory cleanup won't happen.
--- This function determines whether to use store/fixed/dynamic blocks by
--- calculating the block size of each block type and chooses the smallest one.
-local function Deflate(configs, WriteBits, WriteString, FlushWriter, str
- , dictionary)
- local string_table = {}
- local hash_tables = {}
- local is_last_block = nil
- local block_start
- local block_end
- local bitlen_written
- local total_bitlen = FlushWriter(_FLUSH_MODE_NO_FLUSH)
- local strlen = #str
- local offset
-
- local level
- local strategy
- if configs then
- if configs.level then
- level = configs.level
- end
- if configs.strategy then
- strategy = configs.strategy
- end
- end
-
- if not level then
- if strlen < 2048 then
- level = 7
- elseif strlen > 65536 then
- level = 3
- else
- level = 5
- end
- end
-
- while not is_last_block do
- if not block_start then
- block_start = 1
- block_end = 64*1024 - 1
- offset = 0
- else
- block_start = block_end + 1
- block_end = block_end + 32*1024
- offset = block_start - 32*1024 - 1
- end
-
- if block_end >= strlen then
- block_end = strlen
- is_last_block = true
- else
- is_last_block = false
- end
-
- local lcodes, lextra_bits, lcodes_counts, dcodes, dextra_bits
- , dcodes_counts
-
- local HLIT, HDIST, HCLEN, rle_codes_huffman_bitlens
- , rle_codes_huffman_codes, rle_deflate_codes
- , rle_extra_bits, lcodes_huffman_bitlens, lcodes_huffman_codes
- , dcodes_huffman_bitlens, dcodes_huffman_codes
-
- local dynamic_block_bitlen
- local fixed_block_bitlen
- local store_block_bitlen
-
- if level ~= 0 then
-
- -- GetBlockLZ77 needs block_start to block_end+3 to be loaded.
- LoadStringToTable(str, string_table, block_start, block_end + 3
- , offset)
- if block_start == 1 and dictionary then
- local dict_string_table = dictionary.string_table
- local dict_strlen = dictionary.strlen
- for i=0, (-dict_strlen+1)<-257
- and -257 or (-dict_strlen+1), -1 do
- string_table[i] = dict_string_table[dict_strlen+i]
- end
- end
-
- if strategy == "huffman_only" then
- lcodes = {}
- LoadStringToTable(str, lcodes, block_start, block_end
- , block_start-1)
- lextra_bits = {}
- lcodes_counts = {}
- lcodes[block_end - block_start+2] = 256 -- end of block
- for i=1, block_end - block_start+2 do
- local code = lcodes[i]
- lcodes_counts[code] = (lcodes_counts[code] or 0) + 1
- end
- dcodes = {}
- dextra_bits = {}
- dcodes_counts = {}
- else
- lcodes, lextra_bits, lcodes_counts, dcodes, dextra_bits
- , dcodes_counts = GetBlockLZ77Result(level, string_table
- , hash_tables, block_start, block_end, offset, dictionary
- )
- end
-
- HLIT, HDIST, HCLEN, rle_codes_huffman_bitlens
- , rle_codes_huffman_codes, rle_deflate_codes
- , rle_extra_bits, lcodes_huffman_bitlens, lcodes_huffman_codes
- , dcodes_huffman_bitlens, dcodes_huffman_codes =
- GetBlockDynamicHuffmanHeader(lcodes_counts, dcodes_counts)
- dynamic_block_bitlen = GetDynamicHuffmanBlockSize(
- lcodes, dcodes, HCLEN, rle_codes_huffman_bitlens
- , rle_deflate_codes, lcodes_huffman_bitlens
- , dcodes_huffman_bitlens)
- fixed_block_bitlen = GetFixedHuffmanBlockSize(lcodes, dcodes)
- end
-
- store_block_bitlen = GetStoreBlockSize(block_start, block_end
- , total_bitlen)
-
- local min_bitlen = store_block_bitlen
- min_bitlen = (fixed_block_bitlen and fixed_block_bitlen < min_bitlen)
- and fixed_block_bitlen or min_bitlen
- min_bitlen = (dynamic_block_bitlen
- and dynamic_block_bitlen < min_bitlen)
- and dynamic_block_bitlen or min_bitlen
-
- if level == 0 or (strategy ~= "fixed" and strategy ~= "dynamic" and
- store_block_bitlen == min_bitlen) then
- CompressStoreBlock(WriteBits, WriteString, is_last_block
- , str, block_start, block_end, total_bitlen)
- total_bitlen = total_bitlen + store_block_bitlen
- elseif strategy ~= "dynamic" and (
- strategy == "fixed" or fixed_block_bitlen == min_bitlen) then
- CompressFixedHuffmanBlock(WriteBits, is_last_block,
- lcodes, lextra_bits, dcodes, dextra_bits)
- total_bitlen = total_bitlen + fixed_block_bitlen
- elseif strategy == "dynamic" or dynamic_block_bitlen == min_bitlen then
- CompressDynamicHuffmanBlock(WriteBits, is_last_block, lcodes
- , lextra_bits, dcodes, dextra_bits, HLIT, HDIST, HCLEN
- , rle_codes_huffman_bitlens, rle_codes_huffman_codes
- , rle_deflate_codes, rle_extra_bits
- , lcodes_huffman_bitlens, lcodes_huffman_codes
- , dcodes_huffman_bitlens, dcodes_huffman_codes)
- total_bitlen = total_bitlen + dynamic_block_bitlen
- end
-
- if is_last_block then
- bitlen_written = FlushWriter(_FLUSH_MODE_NO_FLUSH)
- else
- bitlen_written = FlushWriter(_FLUSH_MODE_MEMORY_CLEANUP)
- end
-
- assert(bitlen_written == total_bitlen)
-
- -- Memory clean up, so memory consumption does not always grow linearly
- -- , even if input string is > 64K.
- -- Not a very efficient operation, but this operation won't happen
- -- when the input data size is less than 64K.
- if not is_last_block then
- local j
- if dictionary and block_start == 1 then
- j = 0
- while (string_table[j]) do
- string_table[j] = nil
- j = j - 1
- end
- end
- dictionary = nil
- j = 1
- for i = block_end-32767, block_end do
- string_table[j] = string_table[i-offset]
- j = j + 1
- end
-
- for k, t in pairs(hash_tables) do
- local tSize = #t
- if tSize > 0 and block_end+1 - t[1] > 32768 then
- if tSize == 1 then
- hash_tables[k] = nil
- else
- local new = {}
- local newSize = 0
- for i = 2, tSize do
- j = t[i]
- if block_end+1 - j <= 32768 then
- newSize = newSize + 1
- new[newSize] = j
- end
- end
- hash_tables[k] = new
- end
- end
- end
- end
- end
-end
-
---- The description to compression configuration table.
--- Any field can be nil to use its default.
--- Table with keys other than those below is an invalid table.
--- @class table
--- @name compression_configs
--- @field level The compression level ranged from 0 to 9. 0 is no compression.
--- 9 is the slowest but best compression. Use nil for default level.
--- @field strategy The compression strategy. "fixed" to only use fixed deflate
--- compression block. "dynamic" to only use dynamic block. "huffman_only" to
--- do no LZ77 compression. Only do huffman compression.
-
-
--- @see LibDeflate:CompressDeflate(str, configs)
--- @see LibDeflate:CompressDeflateWithDict(str, dictionary, configs)
-local function CompressDeflateInternal(str, dictionary, configs)
- local WriteBits, WriteString, FlushWriter = CreateWriter()
- Deflate(configs, WriteBits, WriteString, FlushWriter, str, dictionary)
- local total_bitlen, result = FlushWriter(_FLUSH_MODE_OUTPUT)
- local padding_bitlen = (8-total_bitlen%8)%8
- return result, padding_bitlen
-end
-
--- @see LibDeflate:CompressZlib
--- @see LibDeflate:CompressZlibWithDict
-local function CompressZlibInternal(str, dictionary, configs)
- local WriteBits, WriteString, FlushWriter = CreateWriter()
-
- local CM = 8 -- Compression method
- local CINFO = 7 --Window Size = 32K
- local CMF = CINFO*16+CM
- WriteBits(CMF, 8)
-
- local FDIST = dictionary and 1 or 0
- local FLEVEL = 2 -- Default compression
- local FLG = FLEVEL*64+FDIST*32
- local FCHECK = (31-(CMF*256+FLG)%31)
- -- The FCHECK value must be such that CMF and FLG,
- -- when viewed as a 16-bit unsigned integer stored
- -- in MSB order (CMF*256 + FLG), is a multiple of 31.
- FLG = FLG + FCHECK
- WriteBits(FLG, 8)
-
- if FDIST == 1 then
- local adler32 = dictionary.adler32
- local byte0 = adler32 % 256
- adler32 = (adler32 - byte0) / 256
- local byte1 = adler32 % 256
- adler32 = (adler32 - byte1) / 256
- local byte2 = adler32 % 256
- adler32 = (adler32 - byte2) / 256
- local byte3 = adler32 % 256
- WriteBits(byte3, 8)
- WriteBits(byte2, 8)
- WriteBits(byte1, 8)
- WriteBits(byte0, 8)
- end
-
- Deflate(configs, WriteBits, WriteString, FlushWriter, str, dictionary)
- FlushWriter(_FLUSH_MODE_BYTE_BOUNDARY)
-
- local adler32 = LibDeflate:Adler32(str)
-
- -- Most significant byte first
- local byte3 = adler32%256
- adler32 = (adler32 - byte3) / 256
- local byte2 = adler32%256
- adler32 = (adler32 - byte2) / 256
- local byte1 = adler32%256
- adler32 = (adler32 - byte1) / 256
- local byte0 = adler32%256
-
- WriteBits(byte0, 8)
- WriteBits(byte1, 8)
- WriteBits(byte2, 8)
- WriteBits(byte3, 8)
- local total_bitlen, result = FlushWriter(_FLUSH_MODE_OUTPUT)
- local padding_bitlen = (8-total_bitlen%8)%8
- return result, padding_bitlen
-end
-
---- Compress using the raw deflate format.
--- @param str [string] The data to be compressed.
--- @param configs [table/nil] The configuration table to control the compression
--- . If nil, use the default configuration.
--- @return [string] The compressed data.
--- @return [integer] The number of bits padded at the end of output.
--- 0 <= bits < 8
--- This means the most significant "bits" of the last byte of the returned
--- compressed data are padding bits and they don't affect decompression.
--- You don't need to use this value unless you want to do some postprocessing
--- to the compressed data.
--- @see compression_configs
--- @see LibDeflate:DecompressDeflate
-function LibDeflate:CompressDeflate(str, configs)
- local arg_valid, arg_err = IsValidArguments(str, false, nil, true, configs)
- if not arg_valid then
- error(("Usage: LibDeflate:CompressDeflate(str, configs): "
- ..arg_err), 2)
- end
- return CompressDeflateInternal(str, nil, configs)
-end
-
---- Compress using the raw deflate format with a preset dictionary.
--- @param str [string] The data to be compressed.
--- @param dictionary [table] The preset dictionary produced by
--- LibDeflate:CreateDictionary
--- @param configs [table/nil] The configuration table to control the compression
--- . If nil, use the default configuration.
--- @return [string] The compressed data.
--- @return [integer] The number of bits padded at the end of output.
--- 0 <= bits < 8
--- This means the most significant "bits" of the last byte of the returned
--- compressed data are padding bits and they don't affect decompression.
--- You don't need to use this value unless you want to do some postprocessing
--- to the compressed data.
--- @see compression_configs
--- @see LibDeflate:CreateDictionary
--- @see LibDeflate:DecompressDeflateWithDict
-function LibDeflate:CompressDeflateWithDict(str, dictionary, configs)
- local arg_valid, arg_err = IsValidArguments(str, true, dictionary
- , true, configs)
- if not arg_valid then
- error(("Usage: LibDeflate:CompressDeflateWithDict"
- .."(str, dictionary, configs): "
- ..arg_err), 2)
- end
- return CompressDeflateInternal(str, dictionary, configs)
-end
-
---- Compress using the zlib format.
--- @param str [string] the data to be compressed.
--- @param configs [table/nil] The configuration table to control the compression
--- . If nil, use the default configuration.
--- @return [string] The compressed data.
--- @return [integer] The number of bits padded at the end of output.
--- Should always be 0.
--- Zlib formatted compressed data never has padding bits at the end.
--- @see compression_configs
--- @see LibDeflate:DecompressZlib
-function LibDeflate:CompressZlib(str, configs)
- local arg_valid, arg_err = IsValidArguments(str, false, nil, true, configs)
- if not arg_valid then
- error(("Usage: LibDeflate:CompressZlib(str, configs): "
- ..arg_err), 2)
- end
- return CompressZlibInternal(str, nil, configs)
-end
-
---- Compress using the zlib format with a preset dictionary.
--- @param str [string] the data to be compressed.
--- @param dictionary [table] A preset dictionary produced
--- by LibDeflate:CreateDictionary()
--- @param configs [table/nil] The configuration table to control the compression
--- . If nil, use the default configuration.
--- @return [string] The compressed data.
--- @return [integer] The number of bits padded at the end of output.
--- Should always be 0.
--- Zlib formatted compressed data never has padding bits at the end.
--- @see compression_configs
--- @see LibDeflate:CreateDictionary
--- @see LibDeflate:DecompressZlibWithDict
-function LibDeflate:CompressZlibWithDict(str, dictionary, configs)
- local arg_valid, arg_err = IsValidArguments(str, true, dictionary
- , true, configs)
- if not arg_valid then
- error(("Usage: LibDeflate:CompressZlibWithDict"
- .."(str, dictionary, configs): "
- ..arg_err), 2)
- end
- return CompressZlibInternal(str, dictionary, configs)
-end
-
---[[ --------------------------------------------------------------------------
- Decompress code
---]] --------------------------------------------------------------------------
-
---[[
- Create a reader to easily reader stuffs as the unit of bits.
- Return values:
- 1. ReadBits(bitlen)
- 2. ReadBytes(bytelen, buffer, buffer_size)
- 3. Decode(huffman_bitlen_count, huffman_symbol, min_bitlen)
- 4. ReaderBitlenLeft()
- 5. SkipToByteBoundary()
---]]
-local function CreateReader(input_string)
- local input = input_string
- local input_strlen = #input_string
- local input_next_byte_pos = 1
- local cache_bitlen = 0
- local cache = 0
-
- -- Read some bits.
- -- To improve speed, this function does not
- -- check if the input has been exhausted.
- -- Use ReaderBitlenLeft() < 0 to check it.
- -- @param bitlen the number of bits to read
- -- @return the data is read.
- local function ReadBits(bitlen)
- local rshift_mask = _pow2[bitlen]
- local code
- if bitlen <= cache_bitlen then
- code = cache % rshift_mask
- cache = (cache - code) / rshift_mask
- cache_bitlen = cache_bitlen - bitlen
- else -- Whether input has been exhausted is not checked.
- local lshift_mask = _pow2[cache_bitlen]
- local byte1, byte2, byte3, byte4 = string_byte(input
- , input_next_byte_pos, input_next_byte_pos+3)
- -- This requires lua number to be at least double ()
- cache = cache + ((byte1 or 0)+(byte2 or 0)*256
- + (byte3 or 0)*65536+(byte4 or 0)*16777216)*lshift_mask
- input_next_byte_pos = input_next_byte_pos + 4
- cache_bitlen = cache_bitlen + 32 - bitlen
- code = cache % rshift_mask
- cache = (cache - code) / rshift_mask
- end
- return code
- end
-
- -- Read some bytes from the reader.
- -- Assume reader is on the byte boundary.
- -- @param bytelen The number of bytes to be read.
- -- @param buffer The byte read will be stored into this buffer.
- -- @param buffer_size The buffer will be modified starting from
- -- buffer[buffer_size+1], ending at buffer[buffer_size+bytelen-1]
- -- @return the new buffer_size
- local function ReadBytes(bytelen, buffer, buffer_size)
- assert(cache_bitlen % 8 == 0)
-
- local byte_from_cache = (cache_bitlen/8 < bytelen)
- and (cache_bitlen/8) or bytelen
- for _=1, byte_from_cache do
- local byte = cache % 256
- buffer_size = buffer_size + 1
- buffer[buffer_size] = string_char(byte)
- cache = (cache - byte) / 256
- end
- cache_bitlen = cache_bitlen - byte_from_cache*8
- bytelen = bytelen - byte_from_cache
- if (input_strlen - input_next_byte_pos - bytelen + 1) * 8
- + cache_bitlen < 0 then
- return -1 -- out of input
- end
- for i=input_next_byte_pos, input_next_byte_pos+bytelen-1 do
- buffer_size = buffer_size + 1
- buffer[buffer_size] = string_sub(input, i, i)
- end
-
- input_next_byte_pos = input_next_byte_pos + bytelen
- return buffer_size
- end
-
- -- Decode huffman code
- -- To improve speed, this function does not check
- -- if the input has been exhausted.
- -- Use ReaderBitlenLeft() < 0 to check it.
- -- Credits for Mark Adler. This code is from puff:Decode()
- -- @see puff:Decode(...)
- -- @param huffman_bitlen_count
- -- @param huffman_symbol
- -- @param min_bitlen The minimum huffman bit length of all symbols
- -- @return The decoded deflate code.
- -- Negative value is returned if decoding fails.
- local function Decode(huffman_bitlen_counts, huffman_symbols, min_bitlen)
- local code = 0
- local first = 0
- local index = 0
- local count
- if min_bitlen > 0 then
- if cache_bitlen < 15 and input then
- local lshift_mask = _pow2[cache_bitlen]
- local byte1, byte2, byte3, byte4 =
- string_byte(input, input_next_byte_pos
- , input_next_byte_pos+3)
- -- This requires lua number to be at least double ()
- cache = cache + ((byte1 or 0)+(byte2 or 0)*256
- +(byte3 or 0)*65536+(byte4 or 0)*16777216)*lshift_mask
- input_next_byte_pos = input_next_byte_pos + 4
- cache_bitlen = cache_bitlen + 32
- end
-
- local rshift_mask = _pow2[min_bitlen]
- cache_bitlen = cache_bitlen - min_bitlen
- code = cache % rshift_mask
- cache = (cache - code) / rshift_mask
- -- Reverse the bits
- code = _reverse_bits_tbl[min_bitlen][code]
-
- count = huffman_bitlen_counts[min_bitlen]
- if code < count then
- return huffman_symbols[code]
- end
- index = count
- first = count * 2
- code = code * 2
- end
-
- for bitlen = min_bitlen+1, 15 do
- local bit
- bit = cache % 2
- cache = (cache - bit) / 2
- cache_bitlen = cache_bitlen - 1
-
- code = (bit==1) and (code + 1 - code % 2) or code
- count = huffman_bitlen_counts[bitlen] or 0
- local diff = code - first
- if diff < count then
- return huffman_symbols[index + diff]
- end
- index = index + count
- first = first + count
- first = first * 2
- code = code * 2
- end
- -- invalid literal/length or distance code
- -- in fixed or dynamic block (run out of code)
- return -10
- end
-
- local function ReaderBitlenLeft()
- return (input_strlen - input_next_byte_pos + 1) * 8 + cache_bitlen
- end
-
- local function SkipToByteBoundary()
- local skipped_bitlen = cache_bitlen%8
- local rshift_mask = _pow2[skipped_bitlen]
- cache_bitlen = cache_bitlen - skipped_bitlen
- cache = (cache - cache % rshift_mask) / rshift_mask
- end
-
- return ReadBits, ReadBytes, Decode, ReaderBitlenLeft, SkipToByteBoundary
-end
-
--- Create a deflate state, so I can pass in less arguments to functions.
--- @param str the whole string to be decompressed.
--- @param dictionary The preset dictionary. nil if not provided.
--- This dictionary should be produced by LibDeflate:CreateDictionary(str)
--- @return The decomrpess state.
-local function CreateDecompressState(str, dictionary)
- local ReadBits, ReadBytes, Decode, ReaderBitlenLeft
- , SkipToByteBoundary = CreateReader(str)
- local state =
- {
- ReadBits = ReadBits,
- ReadBytes = ReadBytes,
- Decode = Decode,
- ReaderBitlenLeft = ReaderBitlenLeft,
- SkipToByteBoundary = SkipToByteBoundary,
- buffer_size = 0,
- buffer = {},
- result_buffer = {},
- dictionary = dictionary,
- }
- return state
-end
-
--- Get the stuffs needed to decode huffman codes
--- @see puff.c:construct(...)
--- @param huffman_bitlen The huffman bit length of the huffman codes.
--- @param max_symbol The maximum symbol
--- @param max_bitlen The min huffman bit length of all codes
--- @return zero or positive for success, negative for failure.
--- @return The count of each huffman bit length.
--- @return A table to convert huffman codes to deflate codes.
--- @return The minimum huffman bit length.
-local function GetHuffmanForDecode(huffman_bitlens, max_symbol, max_bitlen)
- local huffman_bitlen_counts = {}
- local min_bitlen = max_bitlen
- for symbol = 0, max_symbol do
- local bitlen = huffman_bitlens[symbol] or 0
- min_bitlen = (bitlen > 0 and bitlen < min_bitlen)
- and bitlen or min_bitlen
- huffman_bitlen_counts[bitlen] = (huffman_bitlen_counts[bitlen] or 0)+1
- end
-
- if huffman_bitlen_counts[0] == max_symbol+1 then -- No Codes
- return 0, huffman_bitlen_counts, {}, 0 -- Complete, but decode will fail
- end
-
- local left = 1
- for len = 1, max_bitlen do
- left = left * 2
- left = left - (huffman_bitlen_counts[len] or 0)
- if left < 0 then
- return left -- Over-subscribed, return negative
- end
- end
-
- -- Generate offsets info symbol table for each length for sorting
- local offsets = {}
- offsets[1] = 0
- for len = 1, max_bitlen-1 do
- offsets[len + 1] = offsets[len] + (huffman_bitlen_counts[len] or 0)
- end
-
- local huffman_symbols = {}
- for symbol = 0, max_symbol do
- local bitlen = huffman_bitlens[symbol] or 0
- if bitlen ~= 0 then
- local offset = offsets[bitlen]
- huffman_symbols[offset] = symbol
- offsets[bitlen] = offsets[bitlen] + 1
- end
- end
-
- -- Return zero for complete set, positive for incomplete set.
- return left, huffman_bitlen_counts, huffman_symbols, min_bitlen
-end
-
--- Decode a fixed or dynamic huffman blocks, excluding last block identifier
--- and block type identifer.
--- @see puff.c:codes()
--- @param state decompression state that will be modified by this function.
--- @see CreateDecompressState
--- @param ... Read the source code
--- @return 0 on success, other value on failure.
-local function DecodeUntilEndOfBlock(state, lcodes_huffman_bitlens
- , lcodes_huffman_symbols, lcodes_huffman_min_bitlen
- , dcodes_huffman_bitlens, dcodes_huffman_symbols
- , dcodes_huffman_min_bitlen)
- local buffer, buffer_size, ReadBits, Decode, ReaderBitlenLeft
- , result_buffer =
- state.buffer, state.buffer_size, state.ReadBits, state.Decode
- , state.ReaderBitlenLeft, state.result_buffer
- local dictionary = state.dictionary
- local dict_string_table
- local dict_strlen
-
- local buffer_end = 1
- if dictionary and not buffer[0] then
- -- If there is a dictionary, copy the last 258 bytes into
- -- the string_table to make the copy in the main loop quicker.
- -- This is done only once per decompression.
- dict_string_table = dictionary.string_table
- dict_strlen = dictionary.strlen
- buffer_end = -dict_strlen + 1
- for i=0, (-dict_strlen+1)<-257 and -257 or (-dict_strlen+1), -1 do
- buffer[i] = _byte_to_char[dict_string_table[dict_strlen+i]]
- end
- end
-
- repeat
- local symbol = Decode(lcodes_huffman_bitlens
- , lcodes_huffman_symbols, lcodes_huffman_min_bitlen)
- if symbol < 0 or symbol > 285 then
- -- invalid literal/length or distance code in fixed or dynamic block
- return -10
- elseif symbol < 256 then -- Literal
- buffer_size = buffer_size + 1
- buffer[buffer_size] = _byte_to_char[symbol]
- elseif symbol > 256 then -- Length code
- symbol = symbol - 256
- local bitlen = _literal_deflate_code_to_base_len[symbol]
- bitlen = (symbol >= 8)
- and (bitlen
- + ReadBits(_literal_deflate_code_to_extra_bitlen[symbol]))
- or bitlen
- symbol = Decode(dcodes_huffman_bitlens, dcodes_huffman_symbols
- , dcodes_huffman_min_bitlen)
- if symbol < 0 or symbol > 29 then
- -- invalid literal/length or distance code in fixed or dynamic block
- return -10
- end
- local dist = _dist_deflate_code_to_base_dist[symbol]
- dist = (dist > 4) and (dist
- + ReadBits(_dist_deflate_code_to_extra_bitlen[symbol])) or dist
-
- local char_buffer_index = buffer_size-dist+1
- if char_buffer_index < buffer_end then
- -- distance is too far back in fixed or dynamic block
- return -11
- end
- if char_buffer_index >= -257 then
- for _=1, bitlen do
- buffer_size = buffer_size + 1
- buffer[buffer_size] = buffer[char_buffer_index]
- char_buffer_index = char_buffer_index + 1
- end
- else
- char_buffer_index = dict_strlen + char_buffer_index
- for _=1, bitlen do
- buffer_size = buffer_size + 1
- buffer[buffer_size] =
- _byte_to_char[dict_string_table[char_buffer_index]]
- char_buffer_index = char_buffer_index + 1
- end
- end
- end
-
- if ReaderBitlenLeft() < 0 then
- return 2 -- available inflate data did not terminate
- end
-
- if buffer_size >= 65536 then
- result_buffer[#result_buffer+1] =
- table_concat(buffer, "", 1, 32768)
- for i=32769, buffer_size do
- buffer[i-32768] = buffer[i]
- end
- buffer_size = buffer_size - 32768
- buffer[buffer_size+1] = nil
- -- NOTE: buffer[32769..end] and buffer[-257..0] are not cleared.
- -- This is why "buffer_size" variable is needed.
- end
- until symbol == 256
-
- state.buffer_size = buffer_size
-
- return 0
-end
-
--- Decompress a store block
--- @param state decompression state that will be modified by this function.
--- @return 0 if succeeds, other value if fails.
-local function DecompressStoreBlock(state)
- local buffer, buffer_size, ReadBits, ReadBytes, ReaderBitlenLeft
- , SkipToByteBoundary, result_buffer =
- state.buffer, state.buffer_size, state.ReadBits, state.ReadBytes
- , state.ReaderBitlenLeft, state.SkipToByteBoundary, state.result_buffer
-
- SkipToByteBoundary()
- local bytelen = ReadBits(16)
- if ReaderBitlenLeft() < 0 then
- return 2 -- available inflate data did not terminate
- end
- local bytelenComp = ReadBits(16)
- if ReaderBitlenLeft() < 0 then
- return 2 -- available inflate data did not terminate
- end
-
- if bytelen % 256 + bytelenComp % 256 ~= 255 then
- return -2 -- Not one's complement
- end
- if (bytelen-bytelen % 256)/256
- + (bytelenComp-bytelenComp % 256)/256 ~= 255 then
- return -2 -- Not one's complement
- end
-
- -- Note that ReadBytes will skip to the next byte boundary first.
- buffer_size = ReadBytes(bytelen, buffer, buffer_size)
- if buffer_size < 0 then
- return 2 -- available inflate data did not terminate
- end
-
- -- memory clean up when there are enough bytes in the buffer.
- if buffer_size >= 65536 then
- result_buffer[#result_buffer+1] = table_concat(buffer, "", 1, 32768)
- for i=32769, buffer_size do
- buffer[i-32768] = buffer[i]
- end
- buffer_size = buffer_size - 32768
- buffer[buffer_size+1] = nil
- end
- state.buffer_size = buffer_size
- return 0
-end
-
--- Decompress a fixed block
--- @param state decompression state that will be modified by this function.
--- @return 0 if succeeds other value if fails.
-local function DecompressFixBlock(state)
- return DecodeUntilEndOfBlock(state
- , _fix_block_literal_huffman_bitlen_count
- , _fix_block_literal_huffman_to_deflate_code, 7
- , _fix_block_dist_huffman_bitlen_count
- , _fix_block_dist_huffman_to_deflate_code, 5)
-end
-
--- Decompress a dynamic block
--- @param state decompression state that will be modified by this function.
--- @return 0 if success, other value if fails.
-local function DecompressDynamicBlock(state)
- local ReadBits, Decode = state.ReadBits, state.Decode
- local nlen = ReadBits(5) + 257
- local ndist = ReadBits(5) + 1
- local ncode = ReadBits(4) + 4
- if nlen > 286 or ndist > 30 then
- -- dynamic block code description: too many length or distance codes
- return -3
- end
-
- local rle_codes_huffman_bitlens = {}
-
- for i = 1, ncode do
- rle_codes_huffman_bitlens[_rle_codes_huffman_bitlen_order[i]] =
- ReadBits(3)
- end
-
- local rle_codes_err, rle_codes_huffman_bitlen_counts,
- rle_codes_huffman_symbols, rle_codes_huffman_min_bitlen =
- GetHuffmanForDecode(rle_codes_huffman_bitlens, 18, 7)
- if rle_codes_err ~= 0 then -- Require complete code set here
- -- dynamic block code description: code lengths codes incomplete
- return -4
- end
-
- local lcodes_huffman_bitlens = {}
- local dcodes_huffman_bitlens = {}
- -- Read length/literal and distance code length tables
- local index = 0
- while index < nlen + ndist do
- local symbol -- Decoded value
- local bitlen -- Last length to repeat
-
- symbol = Decode(rle_codes_huffman_bitlen_counts
- , rle_codes_huffman_symbols, rle_codes_huffman_min_bitlen)
-
- if symbol < 0 then
- return symbol -- Invalid symbol
- elseif symbol < 16 then
- if index < nlen then
- lcodes_huffman_bitlens[index] = symbol
- else
- dcodes_huffman_bitlens[index-nlen] = symbol
- end
- index = index + 1
- else
- bitlen = 0
- if symbol == 16 then
- if index == 0 then
- -- dynamic block code description: repeat lengths
- -- with no first length
- return -5
- end
- if index-1 < nlen then
- bitlen = lcodes_huffman_bitlens[index-1]
- else
- bitlen = dcodes_huffman_bitlens[index-nlen-1]
- end
- symbol = 3 + ReadBits(2)
- elseif symbol == 17 then -- Repeat zero 3..10 times
- symbol = 3 + ReadBits(3)
- else -- == 18, repeat zero 11.138 times
- symbol = 11 + ReadBits(7)
- end
- if index + symbol > nlen + ndist then
- -- dynamic block code description:
- -- repeat more than specified lengths
- return -6
- end
- while symbol > 0 do -- Repeat last or zero symbol times
- symbol = symbol - 1
- if index < nlen then
- lcodes_huffman_bitlens[index] = bitlen
- else
- dcodes_huffman_bitlens[index-nlen] = bitlen
- end
- index = index + 1
- end
- end
- end
-
- if (lcodes_huffman_bitlens[256] or 0) == 0 then
- -- dynamic block code description: missing end-of-block code
- return -9
- end
-
- local lcodes_err, lcodes_huffman_bitlen_counts
- , lcodes_huffman_symbols, lcodes_huffman_min_bitlen =
- GetHuffmanForDecode(lcodes_huffman_bitlens, nlen-1, 15)
- --dynamic block code description: invalid literal/length code lengths,
- -- Incomplete code ok only for single length 1 code
- if (lcodes_err ~=0 and (lcodes_err < 0
- or nlen ~= (lcodes_huffman_bitlen_counts[0] or 0)
- +(lcodes_huffman_bitlen_counts[1] or 0))) then
- return -7
- end
-
- local dcodes_err, dcodes_huffman_bitlen_counts
- , dcodes_huffman_symbols, dcodes_huffman_min_bitlen =
- GetHuffmanForDecode(dcodes_huffman_bitlens, ndist-1, 15)
- -- dynamic block code description: invalid distance code lengths,
- -- Incomplete code ok only for single length 1 code
- if (dcodes_err ~=0 and (dcodes_err < 0
- or ndist ~= (dcodes_huffman_bitlen_counts[0] or 0)
- + (dcodes_huffman_bitlen_counts[1] or 0))) then
- return -8
- end
-
- -- Build buffman table for literal/length codes
- return DecodeUntilEndOfBlock(state, lcodes_huffman_bitlen_counts
- , lcodes_huffman_symbols, lcodes_huffman_min_bitlen
- , dcodes_huffman_bitlen_counts, dcodes_huffman_symbols
- , dcodes_huffman_min_bitlen)
-end
-
--- Decompress a deflate stream
--- @param state: a decompression state
--- @return the decompressed string if succeeds. nil if fails.
-local function Inflate(state)
- local ReadBits = state.ReadBits
-
- local is_last_block
- while not is_last_block do
- is_last_block = (ReadBits(1) == 1)
- local block_type = ReadBits(2)
- local status
- if block_type == 0 then
- status = DecompressStoreBlock(state)
- elseif block_type == 1 then
- status = DecompressFixBlock(state)
- elseif block_type == 2 then
- status = DecompressDynamicBlock(state)
- else
- return nil, -1 -- invalid block type (type == 3)
- end
- if status ~= 0 then
- return nil, status
- end
- end
-
- state.result_buffer[#state.result_buffer+1] =
- table_concat(state.buffer, "", 1, state.buffer_size)
- local result = table_concat(state.result_buffer)
- return result
-end
-
--- @see LibDeflate:DecompressDeflate(str)
--- @see LibDeflate:DecompressDeflateWithDict(str, dictionary)
-local function DecompressDeflateInternal(str, dictionary)
- local state = CreateDecompressState(str, dictionary)
- local result, status = Inflate(state)
- if not result then
- return nil, status
- end
-
- local bitlen_left = state.ReaderBitlenLeft()
- local bytelen_left = (bitlen_left - bitlen_left % 8) / 8
- return result, bytelen_left
-end
-
--- @see LibDeflate:DecompressZlib(str)
--- @see LibDeflate:DecompressZlibWithDict(str)
-local function DecompressZlibInternal(str, dictionary)
- local state = CreateDecompressState(str, dictionary)
- local ReadBits = state.ReadBits
-
- local CMF = ReadBits(8)
- if state.ReaderBitlenLeft() < 0 then
- return nil, 2 -- available inflate data did not terminate
- end
- local CM = CMF % 16
- local CINFO = (CMF - CM) / 16
- if CM ~= 8 then
- return nil, -12 -- invalid compression method
- end
- if CINFO > 7 then
- return nil, -13 -- invalid window size
- end
-
- local FLG = ReadBits(8)
- if state.ReaderBitlenLeft() < 0 then
- return nil, 2 -- available inflate data did not terminate
- end
- if (CMF*256+FLG)%31 ~= 0 then
- return nil, -14 -- invalid header checksum
- end
-
- local FDIST = ((FLG-FLG%32)/32 % 2)
- local FLEVEL = ((FLG-FLG%64)/64 % 4) -- luacheck: ignore FLEVEL
-
- if FDIST == 1 then
- if not dictionary then
- return nil, -16 -- need dictonary, but dictionary is not provided.
- end
- local byte3 = ReadBits(8)
- local byte2 = ReadBits(8)
- local byte1 = ReadBits(8)
- local byte0 = ReadBits(8)
- local actual_adler32 = byte3*16777216+byte2*65536+byte1*256+byte0
- if state.ReaderBitlenLeft() < 0 then
- return nil, 2 -- available inflate data did not terminate
- end
- if not IsEqualAdler32(actual_adler32, dictionary.adler32) then
- return nil, -17 -- dictionary adler32 does not match
- end
- end
- local result, status = Inflate(state)
- if not result then
- return nil, status
- end
- state.SkipToByteBoundary()
-
- local adler_byte0 = ReadBits(8)
- local adler_byte1 = ReadBits(8)
- local adler_byte2 = ReadBits(8)
- local adler_byte3 = ReadBits(8)
- if state.ReaderBitlenLeft() < 0 then
- return nil, 2 -- available inflate data did not terminate
- end
-
- local adler32_expected = adler_byte0*16777216
- + adler_byte1*65536 + adler_byte2*256 + adler_byte3
- local adler32_actual = LibDeflate:Adler32(result)
- if not IsEqualAdler32(adler32_expected, adler32_actual) then
- return nil, -15 -- Adler32 checksum does not match
- end
-
- local bitlen_left = state.ReaderBitlenLeft()
- local bytelen_left = (bitlen_left - bitlen_left % 8) / 8
- return result, bytelen_left
-end
-
---- Decompress a raw deflate compressed data.
--- @param str [string] The data to be decompressed.
--- @return [string/nil] If the decompression succeeds, return the decompressed
--- data. If the decompression fails, return nil. You should check if this return
--- value is non-nil to know if the decompression succeeds.
--- @return [integer] If the decompression succeeds, return the number of
--- unprocessed bytes in the input compressed data. This return value is a
--- positive integer if the input data is a valid compressed data appended by an
--- arbitary non-empty string. This return value is 0 if the input data does not
--- contain any extra bytes.
--- If the decompression fails (The first return value of this function is nil),
--- this return value is undefined.
--- @see LibDeflate:CompressDeflate
-function LibDeflate:DecompressDeflate(str)
- local arg_valid, arg_err = IsValidArguments(str)
- if not arg_valid then
- error(("Usage: LibDeflate:DecompressDeflate(str): "
- ..arg_err), 2)
- end
- return DecompressDeflateInternal(str)
-end
-
---- Decompress a raw deflate compressed data with a preset dictionary.
--- @param str [string] The data to be decompressed.
--- @param dictionary [table] The preset dictionary used by
--- LibDeflate:CompressDeflateWithDict when the compressed data is produced.
--- Decompression and compression must use the same dictionary.
--- Otherwise wrong decompressed data could be produced without generating any
--- error.
--- @return [string/nil] If the decompression succeeds, return the decompressed
--- data. If the decompression fails, return nil. You should check if this return
--- value is non-nil to know if the decompression succeeds.
--- @return [integer] If the decompression succeeds, return the number of
--- unprocessed bytes in the input compressed data. This return value is a
--- positive integer if the input data is a valid compressed data appended by an
--- arbitary non-empty string. This return value is 0 if the input data does not
--- contain any extra bytes.
--- If the decompression fails (The first return value of this function is nil),
--- this return value is undefined.
--- @see LibDeflate:CompressDeflateWithDict
-function LibDeflate:DecompressDeflateWithDict(str, dictionary)
- local arg_valid, arg_err = IsValidArguments(str, true, dictionary)
- if not arg_valid then
- error(("Usage: LibDeflate:DecompressDeflateWithDict(str, dictionary): "
- ..arg_err), 2)
- end
- return DecompressDeflateInternal(str, dictionary)
-end
-
---- Decompress a zlib compressed data.
--- @param str [string] The data to be decompressed
--- @return [string/nil] If the decompression succeeds, return the decompressed
--- data. If the decompression fails, return nil. You should check if this return
--- value is non-nil to know if the decompression succeeds.
--- @return [integer] If the decompression succeeds, return the number of
--- unprocessed bytes in the input compressed data. This return value is a
--- positive integer if the input data is a valid compressed data appended by an
--- arbitary non-empty string. This return value is 0 if the input data does not
--- contain any extra bytes.
--- If the decompression fails (The first return value of this function is nil),
--- this return value is undefined.
--- @see LibDeflate:CompressZlib
-function LibDeflate:DecompressZlib(str)
- local arg_valid, arg_err = IsValidArguments(str)
- if not arg_valid then
- error(("Usage: LibDeflate:DecompressZlib(str): "
- ..arg_err), 2)
- end
- return DecompressZlibInternal(str)
-end
-
---- Decompress a zlib compressed data with a preset dictionary.
--- @param str [string] The data to be decompressed
--- @param dictionary [table] The preset dictionary used by
--- LibDeflate:CompressDeflateWithDict when the compressed data is produced.
--- Decompression and compression must use the same dictionary.
--- Otherwise wrong decompressed data could be produced without generating any
--- error.
--- @return [string/nil] If the decompression succeeds, return the decompressed
--- data. If the decompression fails, return nil. You should check if this return
--- value is non-nil to know if the decompression succeeds.
--- @return [integer] If the decompression succeeds, return the number of
--- unprocessed bytes in the input compressed data. This return value is a
--- positive integer if the input data is a valid compressed data appended by an
--- arbitary non-empty string. This return value is 0 if the input data does not
--- contain any extra bytes.
--- If the decompression fails (The first return value of this function is nil),
--- this return value is undefined.
--- @see LibDeflate:CompressZlibWithDict
-function LibDeflate:DecompressZlibWithDict(str, dictionary)
- local arg_valid, arg_err = IsValidArguments(str, true, dictionary)
- if not arg_valid then
- error(("Usage: LibDeflate:DecompressZlibWithDict(str, dictionary): "
- ..arg_err), 2)
- end
- return DecompressZlibInternal(str, dictionary)
-end
-
--- Calculate the huffman code of fixed block
-do
- _fix_block_literal_huffman_bitlen = {}
- for sym=0, 143 do
- _fix_block_literal_huffman_bitlen[sym] = 8
- end
- for sym=144, 255 do
- _fix_block_literal_huffman_bitlen[sym] = 9
- end
- for sym=256, 279 do
- _fix_block_literal_huffman_bitlen[sym] = 7
- end
- for sym=280, 287 do
- _fix_block_literal_huffman_bitlen[sym] = 8
- end
-
- _fix_block_dist_huffman_bitlen = {}
- for dist=0, 31 do
- _fix_block_dist_huffman_bitlen[dist] = 5
- end
- local status
- status, _fix_block_literal_huffman_bitlen_count
- , _fix_block_literal_huffman_to_deflate_code =
- GetHuffmanForDecode(_fix_block_literal_huffman_bitlen, 287, 9)
- assert(status == 0)
- status, _fix_block_dist_huffman_bitlen_count,
- _fix_block_dist_huffman_to_deflate_code =
- GetHuffmanForDecode(_fix_block_dist_huffman_bitlen, 31, 5)
- assert(status == 0)
-
- _fix_block_literal_huffman_code =
- GetHuffmanCodeFromBitlen(_fix_block_literal_huffman_bitlen_count
- , _fix_block_literal_huffman_bitlen, 287, 9)
- _fix_block_dist_huffman_code =
- GetHuffmanCodeFromBitlen(_fix_block_dist_huffman_bitlen_count
- , _fix_block_dist_huffman_bitlen, 31, 5)
-end
-
--- Prefix encoding algorithm
--- Credits to LibCompress.
--- The code has been rewritten by the author of LibDeflate.
-------------------------------------------------------------------------------
-
--- to be able to match any requested byte value, the search
--- string must be preprocessed characters to escape with %:
--- ( ) . % + - * ? [ ] ^ $
--- "illegal" byte values:
--- 0 is replaces %z
-local _gsub_escape_table = {
- ["\000"] = "%z", ["("] = "%(", [")"] = "%)", ["."] = "%.",
- ["%"] = "%%", ["+"] = "%+", ["-"] = "%-", ["*"] = "%*",
- ["?"] = "%?", ["["] = "%[", ["]"] = "%]", ["^"] = "%^",
- ["$"] = "%$",
-}
-
-local function escape_for_gsub(str)
- return str:gsub("([%z%(%)%.%%%+%-%*%?%[%]%^%$])", _gsub_escape_table)
-end
-
---- Create a custom codec with encoder and decoder.
--- This codec is used to convert an input string to make it not contain
--- some specific bytes.
--- This created codec and the parameters of this function do NOT take
--- localization into account. One byte (0-255) in the string is exactly one
--- character (0-255).
--- Credits to LibCompress.
--- The code has been rewritten by the author of LibDeflate.
--- @param reserved_chars [string] The created encoder will ensure encoded
--- data does not contain any single character in reserved_chars. This parameter
--- should be non-empty.
--- @param escape_chars [string] The escape character(s) used in the created
--- codec. The codec converts any character included in reserved\_chars /
--- escape\_chars / map\_chars to (one escape char + one character not in
--- reserved\_chars / escape\_chars / map\_chars).
--- You usually only need to provide a length-1 string for this parameter.
--- Length-2 string is only needed when
--- reserved\_chars + escape\_chars + map\_chars is longer than 127.
--- This parameter should be non-empty.
--- @param map_chars [string] The created encoder will map every
--- reserved\_chars:sub(i, i) (1 <= i <= #map\_chars) to map\_chars:sub(i, i).
--- This parameter CAN be empty string.
--- @return [table/nil] If the codec cannot be created, return nil.
--- If the codec can be created according to the given
--- parameters, return the codec, which is a encode/decode table.
--- The table contains two functions:
--- t:Encode(str) returns the encoded string.
--- t:Decode(str) returns the decoded string if succeeds. nil if fails.
--- @return [nil/string] If the codec is successfully created, return nil.
--- If not, return a string that describes the reason why the codec cannot be
--- created.
--- @usage
--- -- Create an encoder/decoder that maps all "\000" to "\003",
--- -- and escape "\001" (and "\002" and "\003") properly
--- local codec = LibDeflate:CreateCodec("\000\001", "\002", "\003")
---
--- local encoded = codec:Encode(SOME_STRING)
--- -- "encoded" does not contain "\000" or "\001"
--- local decoded = codec:Decode(encoded)
--- -- assert(decoded == SOME_STRING)
-function LibDeflate:CreateCodec(reserved_chars, escape_chars
- , map_chars)
- if type(reserved_chars) ~= "string"
- or type(escape_chars) ~= "string"
- or type(map_chars) ~= "string" then
- error(
- "Usage: LibDeflate:CreateCodec(reserved_chars,"
- .." escape_chars, map_chars):"
- .." All arguments must be string.", 2)
- end
-
- if escape_chars == "" then
- return nil, "No escape characters supplied."
- end
- if #reserved_chars < #map_chars then
- return nil, "The number of reserved characters must be"
- .." at least as many as the number of mapped chars."
- end
- if reserved_chars == "" then
- return nil, "No characters to encode."
- end
-
- local encode_bytes = reserved_chars..escape_chars..map_chars
- -- build list of bytes not available as a suffix to a prefix byte
- local taken = {}
- for i = 1, #encode_bytes do
- local byte = string_byte(encode_bytes, i, i)
- if taken[byte] then
- return nil, "There must be no duplicate characters in the"
- .." concatenation of reserved_chars, escape_chars and"
- .." map_chars."
- end
- taken[byte] = true
- end
-
- local decode_patterns = {}
- local decode_repls = {}
-
- -- the encoding can be a single gsub
- -- , but the decoding can require multiple gsubs
- local encode_search = {}
- local encode_translate = {}
-
- -- map single byte to single byte
- if #map_chars > 0 then
- local decode_search = {}
- local decode_translate = {}
- for i = 1, #map_chars do
- local from = string_sub(reserved_chars, i, i)
- local to = string_sub(map_chars, i, i)
- encode_translate[from] = to
- encode_search[#encode_search+1] = from
- decode_translate[to] = from
- decode_search[#decode_search+1] = to
- end
- decode_patterns[#decode_patterns+1] =
- "([".. escape_for_gsub(table_concat(decode_search)).."])"
- decode_repls[#decode_repls+1] = decode_translate
- end
-
- local escape_char_index = 1
- local escape_char = string_sub(escape_chars
- , escape_char_index, escape_char_index)
- -- map single byte to double-byte
- local r = 0 -- suffix char value to the escapeChar
-
- local decode_search = {}
- local decode_translate = {}
- for i = 1, #encode_bytes do
- local c = string_sub(encode_bytes, i, i)
- if not encode_translate[c] then
- while r >= 256 or taken[r] do
- r = r + 1
- if r > 255 then -- switch to next escapeChar
- decode_patterns[#decode_patterns+1] =
- escape_for_gsub(escape_char)
- .."(["
- .. escape_for_gsub(table_concat(decode_search)).."])"
- decode_repls[#decode_repls+1] = decode_translate
-
- escape_char_index = escape_char_index + 1
- escape_char = string_sub(escape_chars, escape_char_index
- , escape_char_index)
- r = 0
- decode_search = {}
- decode_translate = {}
-
- if not escape_char or escape_char == "" then
- -- actually I don't need to check
- -- "not ecape_char", but what if Lua changes
- -- the behavior of string.sub() in the future?
- -- we are out of escape chars and we need more!
- return nil, "Out of escape characters."
- end
- end
- end
-
- local char_r = _byte_to_char[r]
- encode_translate[c] = escape_char..char_r
- encode_search[#encode_search+1] = c
- decode_translate[char_r] = c
- decode_search[#decode_search+1] = char_r
- r = r + 1
- end
- if i == #encode_bytes then
- decode_patterns[#decode_patterns+1] =
- escape_for_gsub(escape_char).."(["
- .. escape_for_gsub(table_concat(decode_search)).."])"
- decode_repls[#decode_repls+1] = decode_translate
- end
- end
-
- local codec = {}
-
- local encode_pattern = "(["
- .. escape_for_gsub(table_concat(encode_search)).."])"
- local encode_repl = encode_translate
-
- function codec:Encode(str)
- if type(str) ~= "string" then
- error(("Usage: codec:Encode(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- return string_gsub(str, encode_pattern, encode_repl)
- end
-
- local decode_tblsize = #decode_patterns
- local decode_fail_pattern = "(["
- .. escape_for_gsub(reserved_chars).."])"
-
- function codec:Decode(str)
- if type(str) ~= "string" then
- error(("Usage: codec:Decode(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- if string_find(str, decode_fail_pattern) then
- return nil
- end
- for i = 1, decode_tblsize do
- str = string_gsub(str, decode_patterns[i], decode_repls[i])
- end
- return str
- end
-
- return codec
-end
-
-local _addon_channel_codec
-
-local function GenerateWoWAddonChannelCodec()
- return LibDeflate:CreateCodec("\000", "\001", "")
-end
-
---- Encode the string to make it ready to be transmitted in World of
--- Warcraft addon channel.
--- The encoded string is guaranteed to contain no NULL ("\000") character.
--- @param str [string] The string to be encoded.
--- @return The encoded string.
--- @see LibDeflate:DecodeForWoWAddonChannel
-function LibDeflate:EncodeForWoWAddonChannel(str)
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:EncodeForWoWAddonChannel(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- if not _addon_channel_codec then
- _addon_channel_codec = GenerateWoWAddonChannelCodec()
- end
- return _addon_channel_codec:Encode(str)
-end
-
---- Decode the string produced by LibDeflate:EncodeForWoWAddonChannel
--- @param str [string] The string to be decoded.
--- @return [string/nil] The decoded string if succeeds. nil if fails.
--- @see LibDeflate:EncodeForWoWAddonChannel
-function LibDeflate:DecodeForWoWAddonChannel(str)
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:DecodeForWoWAddonChannel(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- if not _addon_channel_codec then
- _addon_channel_codec = GenerateWoWAddonChannelCodec()
- end
- return _addon_channel_codec:Decode(str)
-end
-
--- For World of Warcraft Chat Channel Encoding
--- Credits to LibCompress.
--- The code has been rewritten by the author of LibDeflate.
--- Following byte values are not allowed:
--- \000, s, S, \010, \013, \124, %
--- Because SendChatMessage will error
--- if an UTF8 multibyte character is incomplete,
--- all character values above 127 have to be encoded to avoid this.
--- This costs quite a bit of bandwidth (about 13-14%)
--- Also, because drunken status is unknown for the received
--- , strings used with SendChatMessage should be terminated with
--- an identifying byte value, after which the server MAY add "...hic!"
--- or as much as it can fit(!).
--- Pass the identifying byte as a reserved character to this function
--- to ensure the encoding doesn't contain that value.
--- or use this: local message, match = arg1:gsub("^(.*)\029.-$", "%1")
--- arg1 is message from channel, \029 is the string terminator
--- , but may be used in the encoded datastream as well. :-)
--- This encoding will expand data anywhere from:
--- 0% (average with pure ascii text)
--- 53.5% (average with random data valued zero to 255)
--- 100% (only encoding data that encodes to two bytes)
-local function GenerateWoWChatChannelCodec()
- local r = {}
- for i = 128, 255 do
- r[#r+1] = _byte_to_char[i]
- end
-
- local reserved_chars = "sS\000\010\013\124%"..table_concat(r)
- return LibDeflate:CreateCodec(reserved_chars
- , "\029\031", "\015\020")
-end
-
-local _chat_channel_codec
-
---- Encode the string to make it ready to be transmitted in World of
--- Warcraft chat channel.
--- See also https://wow.gamepedia.com/ValidChatMessageCharacters
--- @param str [string] The string to be encoded.
--- @return [string] The encoded string.
--- @see LibDeflate:DecodeForWoWChatChannel
-function LibDeflate:EncodeForWoWChatChannel(str)
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:EncodeForWoWChatChannel(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- if not _chat_channel_codec then
- _chat_channel_codec = GenerateWoWChatChannelCodec()
- end
- return _chat_channel_codec:Encode(str)
-end
-
---- Decode the string produced by LibDeflate:EncodeForWoWChatChannel.
--- @param str [string] The string to be decoded.
--- @return [string/nil] The decoded string if succeeds. nil if fails.
--- @see LibDeflate:EncodeForWoWChatChannel
-function LibDeflate:DecodeForWoWChatChannel(str)
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:DecodeForWoWChatChannel(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- if not _chat_channel_codec then
- _chat_channel_codec = GenerateWoWChatChannelCodec()
- end
- return _chat_channel_codec:Decode(str)
-end
-
--- Credits to WeakAuras2 and Galmok for the 6 bit encoding algorithm.
--- The code has been rewritten by the author of LibDeflate.
--- The result of encoding will be 25% larger than the
--- origin string, but every single byte of the encoding result will be
--- printable characters as the following.
-local _byte_to_6bit_char = {
- [0]="a", "b", "c", "d", "e", "f", "g", "h",
- "i", "j", "k", "l", "m", "n", "o", "p",
- "q", "r", "s", "t", "u", "v", "w", "x",
- "y", "z", "A", "B", "C", "D", "E", "F",
- "G", "H", "I", "J", "K", "L", "M", "N",
- "O", "P", "Q", "R", "S", "T", "U", "V",
- "W", "X", "Y", "Z", "0", "1", "2", "3",
- "4", "5", "6", "7", "8", "9", "(", ")",
-}
-
-local _6bit_to_byte = {
- [97]=0,[98]=1,[99]=2,[100]=3,[101]=4,[102]=5,[103]=6,[104]=7,
- [105]=8,[106]=9,[107]=10,[108]=11,[109]=12,[110]=13,[111]=14,[112]=15,
- [113]=16,[114]=17,[115]=18,[116]=19,[117]=20,[118]=21,[119]=22,[120]=23,
- [121]=24,[122]=25,[65]=26,[66]=27,[67]=28,[68]=29,[69]=30,[70]=31,
- [71]=32,[72]=33,[73]=34,[74]=35,[75]=36,[76]=37,[77]=38,[78]=39,
- [79]=40,[80]=41,[81]=42,[82]=43,[83]=44,[84]=45,[85]=46,[86]=47,
- [87]=48,[88]=49,[89]=50,[90]=51,[48]=52,[49]=53,[50]=54,[51]=55,
- [52]=56,[53]=57,[54]=58,[55]=59,[56]=60,[57]=61,[40]=62,[41]=63,
-}
-
---- Encode the string to make it printable.
---
--- Credit to WeakAuras2, this function is equivalant to the implementation
--- it is using right now.
--- The code has been rewritten by the author of LibDeflate.
--- The encoded string will be 25% larger than the origin string. However, every
--- single byte of the encoded string will be one of 64 printable ASCII
--- characters, which are can be easier copied, pasted and displayed.
--- (26 lowercase letters, 26 uppercase letters, 10 numbers digits,
--- left parenthese, or right parenthese)
--- @param str [string] The string to be encoded.
--- @return [string] The encoded string.
-function LibDeflate:EncodeForPrint(str)
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:EncodeForPrint(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- local strlen = #str
- local strlenMinus2 = strlen - 2
- local i = 1
- local buffer = {}
- local buffer_size = 0
- while i <= strlenMinus2 do
- local x1, x2, x3 = string_byte(str, i, i+2)
- i = i + 3
- local cache = x1+x2*256+x3*65536
- local b1 = cache % 64
- cache = (cache - b1) / 64
- local b2 = cache % 64
- cache = (cache - b2) / 64
- local b3 = cache % 64
- local b4 = (cache - b3) / 64
- buffer_size = buffer_size + 1
- buffer[buffer_size] =
- _byte_to_6bit_char[b1].._byte_to_6bit_char[b2]
- .._byte_to_6bit_char[b3].._byte_to_6bit_char[b4]
- end
-
- local cache = 0
- local cache_bitlen = 0
- while i <= strlen do
- local x = string_byte(str, i, i)
- cache = cache + x * _pow2[cache_bitlen]
- cache_bitlen = cache_bitlen + 8
- i = i + 1
- end
- while cache_bitlen > 0 do
- local bit6 = cache % 64
- buffer_size = buffer_size + 1
- buffer[buffer_size] = _byte_to_6bit_char[bit6]
- cache = (cache - bit6) / 64
- cache_bitlen = cache_bitlen - 6
- end
-
- return table_concat(buffer)
-end
-
---- Decode the printable string produced by LibDeflate:EncodeForPrint.
--- "str" will have its prefixed and trailing control characters or space
--- removed before it is decoded, so it is easier to use if "str" comes form
--- user copy and paste with some prefixed or trailing spaces.
--- Then decode fails if the string contains any characters cant be produced by
--- LibDeflate:EncodeForPrint. That means, decode fails if the string contains a
--- characters NOT one of 26 lowercase letters, 26 uppercase letters,
--- 10 numbers digits, left parenthese, or right parenthese.
--- @param str [string] The string to be decoded
--- @return [string/nil] The decoded string if succeeds. nil if fails.
-function LibDeflate:DecodeForPrint(str)
- if type(str) ~= "string" then
- error(("Usage: LibDeflate:DecodeForPrint(str):"
- .." 'str' - string expected got '%s'."):format(type(str)), 2)
- end
- str = str:gsub("^[%c ]+", "")
- str = str:gsub("[%c ]+$", "")
-
- local strlen = #str
- if strlen == 1 then
- return nil
- end
- local strlenMinus3 = strlen - 3
- local i = 1
- local buffer = {}
- local buffer_size = 0
- while i <= strlenMinus3 do
- local x1, x2, x3, x4 = string_byte(str, i, i+3)
- x1 = _6bit_to_byte[x1]
- x2 = _6bit_to_byte[x2]
- x3 = _6bit_to_byte[x3]
- x4 = _6bit_to_byte[x4]
- if not (x1 and x2 and x3 and x4) then
- return nil
- end
- i = i + 4
- local cache = x1+x2*64+x3*4096+x4*262144
- local b1 = cache % 256
- cache = (cache - b1) / 256
- local b2 = cache % 256
- local b3 = (cache - b2) / 256
- buffer_size = buffer_size + 1
- buffer[buffer_size] =
- _byte_to_char[b1].._byte_to_char[b2].._byte_to_char[b3]
- end
-
- local cache = 0
- local cache_bitlen = 0
- while i <= strlen do
- local x = string_byte(str, i, i)
- x = _6bit_to_byte[x]
- if not x then
- return nil
- end
- cache = cache + x * _pow2[cache_bitlen]
- cache_bitlen = cache_bitlen + 6
- i = i + 1
- end
-
- while cache_bitlen >= 8 do
- local byte = cache % 256
- buffer_size = buffer_size + 1
- buffer[buffer_size] = _byte_to_char[byte]
- cache = (cache - byte) / 256
- cache_bitlen = cache_bitlen - 8
- end
-
- return table_concat(buffer)
-end
-
-local function InternalClearCache()
- _chat_channel_codec = nil
- _addon_channel_codec = nil
-end
-
--- For test. Don't use the functions in this table for real application.
--- Stuffs in this table is subject to change.
-LibDeflate.internals = {
- LoadStringToTable = LoadStringToTable,
- IsValidDictionary = IsValidDictionary,
- IsEqualAdler32 = IsEqualAdler32,
- _byte_to_6bit_char = _byte_to_6bit_char,
- _6bit_to_byte = _6bit_to_byte,
- InternalClearCache = InternalClearCache,
-}
-
---[[-- Commandline options
-@class table
-@name CommandlineOptions
-@usage lua LibDeflate.lua [OPTION] [INPUT] [OUTPUT]
-\-0 store only. no compression.
-\-1 fastest compression.
-\-9 slowest and best compression.
-\-d do decompression instead of compression.
-\--dict specify the file that contains
-the entire preset dictionary.
-\-h give this help.
-\--strategy specify a special compression strategy.
-\-v print the version and copyright info.
-\--zlib use zlib format instead of raw deflate.
-]]
-
--- currently no plan to support stdin and stdout.
--- Because Lua in Windows does not set stdout with binary mode.
-if io and os and debug and _G.arg then
- local io = io
- local os = os
- local debug = debug
- local arg = _G.arg
- local debug_info = debug.getinfo(1)
- if debug_info.source == arg[0]
- or debug_info.short_src == arg[0] then
- -- We are indeed runnning THIS file from the commandline.
- local input
- local output
- local i = 1
- local status
- local is_zlib = false
- local is_decompress = false
- local level
- local strategy
- local dictionary
- while (arg[i]) do
- local a = arg[i]
- if a == "-h" then
- print(LibDeflate._COPYRIGHT
- .."\nUsage: lua LibDeflate.lua [OPTION] [INPUT] [OUTPUT]\n"
- .." -0 store only. no compression.\n"
- .." -1 fastest compression.\n"
- .." -9 slowest and best compression.\n"
- .." -d do decompression instead of compression.\n"
- .." --dict specify the file that contains"
- .." the entire preset dictionary.\n"
- .." -h give this help.\n"
- .." --strategy "
- .." specify a special compression strategy.\n"
- .." -v print the version and copyright info.\n"
- .." --zlib use zlib format instead of raw deflate.\n")
- os.exit(0)
- elseif a == "-v" then
- print(LibDeflate._COPYRIGHT)
- os.exit(0)
- elseif a:find("^%-[0-9]$") then
- level = tonumber(a:sub(2, 2))
- elseif a == "-d" then
- is_decompress = true
- elseif a == "--dict" then
- i = i + 1
- local dict_filename = arg[i]
- if not dict_filename then
- io.stderr:write("You must speicify the dict filename")
- os.exit(1)
- end
- local dict_file, dict_status = io.open(dict_filename, "rb")
- if not dict_file then
- io.stderr:write(
- ("LibDeflate: Cannot read the dictionary file '%s': %s")
- :format(dict_filename, dict_status))
- os.exit(1)
- end
- local dict_str = dict_file:read("*all")
- dict_file:close()
- -- In your lua program, you should pass in adler32 as a CONSTANT
- -- , so it actually prevent you from modifying dictionary
- -- unintentionally during the program development. I do this
- -- here just because no convenient way to verify in commandline.
- dictionary = LibDeflate:CreateDictionary(dict_str,
- #dict_str, LibDeflate:Adler32(dict_str))
- elseif a == "--strategy" then
- -- Not sure if I should check error here
- -- If I do, redudant code.
- i = i + 1
- strategy = arg[i]
- elseif a == "--zlib" then
- is_zlib = true
- elseif a:find("^%-") then
- io.stderr:write(("LibDeflate: Invalid argument: %s")
- :format(a))
- os.exit(1)
- else
- if not input then
- input, status = io.open(a, "rb")
- if not input then
- io.stderr:write(
- ("LibDeflate: Cannot read the file '%s': %s")
- :format(a, tostring(status)))
- os.exit(1)
- end
- elseif not output then
- output, status = io.open(a, "wb")
- if not output then
- io.stderr:write(
- ("LibDeflate: Cannot write the file '%s': %s")
- :format(a, tostring(status)))
- os.exit(1)
- end
- end
- end
- i = i + 1
- end -- while (arg[i])
-
- if not input or not output then
- io.stderr:write("LibDeflate:"
- .." You must specify both input and output files.")
- os.exit(1)
- end
-
- local input_data = input:read("*all")
- local configs = {
- level = level,
- strategy = strategy,
- }
- local output_data
- if not is_decompress then
- if not is_zlib then
- if not dictionary then
- output_data =
- LibDeflate:CompressDeflate(input_data, configs)
- else
- output_data =
- LibDeflate:CompressDeflateWithDict(input_data, dictionary
- , configs)
- end
- else
- if not dictionary then
- output_data =
- LibDeflate:CompressZlib(input_data, configs)
- else
- output_data =
- LibDeflate:CompressZlibWithDict(input_data, dictionary
- , configs)
- end
- end
- else
- if not is_zlib then
- if not dictionary then
- output_data = LibDeflate:DecompressDeflate(input_data)
- else
- output_data = LibDeflate:DecompressDeflateWithDict(
- input_data, dictionary)
- end
- else
- if not dictionary then
- output_data = LibDeflate:DecompressZlib(input_data)
- else
- output_data = LibDeflate:DecompressZlibWithDict(
- input_data, dictionary)
- end
- end
- end
-
- if not output_data then
- io.stderr:write("LibDeflate: Decompress fails.")
- os.exit(1)
- end
-
- output:write(output_data)
- if input and input ~= io.stdin then
- input:close()
- end
- if output and output ~= io.stdout then
- output:close()
- end
-
- io.stderr:write(("Successfully writes %d bytes"):format(
- output_data:len()))
- os.exit(0)
- end
-end
-
-return LibDeflate