-
Notifications
You must be signed in to change notification settings - Fork 1
/
basexx.lua
297 lines (240 loc) · 9.28 KB
/
basexx.lua
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
--------------------------------------------------------------------------------
-- util functions
--------------------------------------------------------------------------------
local function divide_string( str, max )
local result = {}
local start = 1
for i = 1, #str do
if i % max == 0 then
table.insert( result, str:sub( start, i ) )
start = i + 1
elseif i == #str then
table.insert( result, str:sub( start, i ) )
end
end
return result
end
local function number_to_bit( num, length )
local bits = {}
while num > 0 do
local rest = math.floor( math.fmod( num, 2 ) )
table.insert( bits, rest )
num = ( num - rest ) / 2
end
while #bits < length do
table.insert( bits, "0" )
end
return string.reverse( table.concat( bits ) )
end
local function ignore_set( str, set )
if set then
str = str:gsub( "["..set.."]", "" )
end
return str
end
local function pure_from_bit( str )
return ( str:gsub( '........', function ( cc )
return string.char( tonumber( cc, 2 ) )
end ) )
end
local function unexpected_char_error( str, pos )
local c = string.sub( str, pos, pos )
return string.format( "unexpected character at position %d: '%s'", pos, c )
end
--------------------------------------------------------------------------------
local basexx = {}
--------------------------------------------------------------------------------
-- base2(bitfield) decode and encode function
--------------------------------------------------------------------------------
local bitMap = { o = "0", i = "1", l = "1" }
function basexx.from_bit( str, ignore )
str = ignore_set( str, ignore )
str = string.lower( str )
str = str:gsub( '[ilo]', function( c ) return bitMap[ c ] end )
local pos = string.find( str, "[^01]" )
if pos then return nil, unexpected_char_error( str, pos ) end
return pure_from_bit( str )
end
function basexx.to_bit( str )
return ( str:gsub( '.', function ( c )
local byte = string.byte( c )
local bits = {}
for _ = 1,8 do
table.insert( bits, byte % 2 )
byte = math.floor( byte / 2 )
end
return table.concat( bits ):reverse()
end ) )
end
--------------------------------------------------------------------------------
-- base16(hex) decode and encode function
--------------------------------------------------------------------------------
function basexx.from_hex( str, ignore )
str = ignore_set( str, ignore )
local pos = string.find( str, "[^%x]" )
if pos then return nil, unexpected_char_error( str, pos ) end
return ( str:gsub( '..', function ( cc )
return string.char( tonumber( cc, 16 ) )
end ) )
end
function basexx.to_hex( str )
return ( str:gsub( '.', function ( c )
return string.format('%02X', string.byte( c ) )
end ) )
end
--------------------------------------------------------------------------------
-- generic function to decode and encode base32/base64
--------------------------------------------------------------------------------
local function from_basexx( str, alphabet, bits )
local result = {}
for i = 1, #str do
local c = string.sub( str, i, i )
if c ~= '=' then
local index = string.find( alphabet, c, 1, true )
if not index then
return nil, unexpected_char_error( str, i )
end
table.insert( result, number_to_bit( index - 1, bits ) )
end
end
local value = table.concat( result )
local pad = #value % 8
return pure_from_bit( string.sub( value, 1, #value - pad ) )
end
local function to_basexx( str, alphabet, bits, pad )
local bitString = basexx.to_bit( str )
local chunks = divide_string( bitString, bits )
local result = {}
for _,value in ipairs( chunks ) do
if ( #value < bits ) then
value = value .. string.rep( '0', bits - #value )
end
local pos = tonumber( value, 2 ) + 1
table.insert( result, alphabet:sub( pos, pos ) )
end
table.insert( result, pad )
return table.concat( result )
end
--------------------------------------------------------------------------------
-- rfc 3548: http://www.rfc-editor.org/rfc/rfc3548.txt
--------------------------------------------------------------------------------
local base32Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
local base32PadMap = { "", "======", "====", "===", "=" }
function basexx.from_base32( str, ignore )
str = ignore_set( str, ignore )
return from_basexx( string.upper( str ), base32Alphabet, 5 )
end
function basexx.to_base32( str )
return to_basexx( str, base32Alphabet, 5, base32PadMap[ #str % 5 + 1 ] )
end
--------------------------------------------------------------------------------
-- crockford: http://www.crockford.com/wrmg/base32.html
--------------------------------------------------------------------------------
local crockfordAlphabet = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"
local crockfordMap = { O = "0", I = "1", L = "1" }
function basexx.from_crockford( str, ignore )
str = ignore_set( str, ignore )
str = string.upper( str )
str = str:gsub( '[ILOU]', function( c ) return crockfordMap[ c ] end )
return from_basexx( str, crockfordAlphabet, 5 )
end
function basexx.to_crockford( str )
return to_basexx( str, crockfordAlphabet, 5, "" )
end
--------------------------------------------------------------------------------
-- base64 decode and encode function
--------------------------------------------------------------------------------
local base64Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"..
"abcdefghijklmnopqrstuvwxyz"..
"0123456789+/"
local base64PadMap = { "", "==", "=" }
function basexx.from_base64( str, ignore )
str = ignore_set( str, ignore )
return from_basexx( str, base64Alphabet, 6 )
end
function basexx.to_base64( str )
return to_basexx( str, base64Alphabet, 6, base64PadMap[ #str % 3 + 1 ] )
end
--------------------------------------------------------------------------------
-- URL safe base64 decode and encode function
--------------------------------------------------------------------------------
local url64Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"..
"abcdefghijklmnopqrstuvwxyz"..
"0123456789-_"
function basexx.from_url64( str, ignore )
str = ignore_set( str, ignore )
return from_basexx( str, url64Alphabet, 6 )
end
function basexx.to_url64( str )
return to_basexx( str, url64Alphabet, 6, "" )
end
--------------------------------------------------------------------------------
--
--------------------------------------------------------------------------------
local function length_error( len, d )
return string.format( "invalid length: %d - must be a multiple of %d", len, d )
end
local z85Decoder = { 0x00, 0x44, 0x00, 0x54, 0x53, 0x52, 0x48, 0x00,
0x4B, 0x4C, 0x46, 0x41, 0x00, 0x3F, 0x3E, 0x45,
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x40, 0x00, 0x49, 0x42, 0x4A, 0x47,
0x51, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A,
0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32,
0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
0x3B, 0x3C, 0x3D, 0x4D, 0x00, 0x4E, 0x43, 0x00,
0x00, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10,
0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,
0x21, 0x22, 0x23, 0x4F, 0x00, 0x50, 0x00, 0x00 }
function basexx.from_z85( str, ignore )
str = ignore_set( str, ignore )
if ( #str % 5 ) ~= 0 then
return nil, length_error( #str, 5 )
end
local result = {}
local value = 0
for i = 1, #str do
local index = string.byte( str, i ) - 31
if index < 1 or index >= #z85Decoder then
return nil, unexpected_char_error( str, i )
end
value = ( value * 85 ) + z85Decoder[ index ]
if ( i % 5 ) == 0 then
local divisor = 256 * 256 * 256
while divisor ~= 0 do
local b = math.floor( value / divisor ) % 256
table.insert( result, string.char( b ) )
divisor = math.floor( divisor / 256 )
end
value = 0
end
end
return table.concat( result )
end
local z85Encoder = "0123456789"..
"abcdefghijklmnopqrstuvwxyz"..
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"..
".-:+=^!/*?&<>()[]{}@%$#"
function basexx.to_z85( str )
if ( #str % 4 ) ~= 0 then
return nil, length_error( #str, 4 )
end
local result = {}
local value = 0
for i = 1, #str do
local b = string.byte( str, i )
value = ( value * 256 ) + b
if ( i % 4 ) == 0 then
local divisor = 85 * 85 * 85 * 85
while divisor ~= 0 do
local index = ( math.floor( value / divisor ) % 85 ) + 1
table.insert( result, z85Encoder:sub( index, index ) )
divisor = math.floor( divisor / 85 )
end
value = 0
end
end
return table.concat( result )
end
--------------------------------------------------------------------------------
return basexx