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1 | ------------------------------------------------------------------ utils | |
2 | - | local controls = {["\n"]="\\n", ["\r"]="\\r", ["\t"]="\\t", ["\b"]="\\b", ["\f"]="\\f", ["\""]="\\\"", ["\\"]="\\\\"} |
2 | + | local controls = {["\n"]="\\n", ["\r"]="\\r", ["\t"]="\\t", ["\b"]="\\b", ["\f"]="\\f", ["\""]="\\\"", ["\\"]="\\\\", ["/"] = "\\/"} |
3 | -- Encode stuff with fancy Unicode sequences. Kind of wrong. Oh well. | |
4 | for i = 0, 31 do | |
5 | controls[string.char(i)] = string.format("\\u%04x", i) | |
6 | end | |
7 | ||
8 | local function isArray(t) | |
9 | local max = 0 | |
10 | for k,v in pairs(t) do | |
11 | if type(k) ~= "number" then | |
12 | return false | |
13 | elseif k > max then | |
14 | max = k | |
15 | end | |
16 | end | |
17 | return max == #t | |
18 | end | |
19 | ||
20 | local whites = {['\n']=true; ['\r']=true; ['\t']=true; [' ']=true; [',']=true; [':']=true} | |
21 | function removeWhite(str) | |
22 | while whites[str:sub(1, 1)] do | |
23 | str = str:sub(2) | |
24 | end | |
25 | return str | |
26 | end | |
27 | ||
28 | ------------------------------------------------------------------ encoding | |
29 | ||
30 | local function encodeCommon(val, pretty, tabLevel, tTracking) | |
31 | local str = "" | |
32 | ||
33 | -- Tabbing util | |
34 | local function tab(s) | |
35 | str = str .. ("\t"):rep(tabLevel) .. s | |
36 | end | |
37 | ||
38 | local function arrEncoding(val, bracket, closeBracket, iterator, loopFunc) | |
39 | str = str .. bracket | |
40 | if pretty then | |
41 | str = str .. "\n" | |
42 | tabLevel = tabLevel + 1 | |
43 | end | |
44 | for k,v in iterator(val) do | |
45 | tab("") | |
46 | loopFunc(k,v) | |
47 | str = str .. "," | |
48 | if pretty then str = str .. "\n" end | |
49 | end | |
50 | if pretty then | |
51 | tabLevel = tabLevel - 1 | |
52 | end | |
53 | if str:sub(-2) == ",\n" then | |
54 | str = str:sub(1, -3) .. "\n" | |
55 | elseif str:sub(-1) == "," then | |
56 | str = str:sub(1, -2) | |
57 | end | |
58 | tab(closeBracket) | |
59 | end | |
60 | ||
61 | -- Table encoding | |
62 | if type(val) == "table" then | |
63 | assert(not tTracking[val], "Cannot encode a table holding itself recursively") | |
64 | tTracking[val] = true | |
65 | if isArray(val) then | |
66 | arrEncoding(val, "[", "]", ipairs, function(k,v) | |
67 | str = str .. encodeCommon(v, pretty, tabLevel, tTracking) | |
68 | end) | |
69 | else | |
70 | arrEncoding(val, "{", "}", pairs, function(k,v) | |
71 | assert(type(k) == "string", "JSON object keys must be strings", 2) | |
72 | str = str .. encodeCommon(k, pretty, tabLevel, tTracking) | |
73 | str = str .. (pretty and ": " or ":") .. encodeCommon(v, pretty, tabLevel, tTracking) | |
74 | end) | |
75 | end | |
76 | -- String encoding | |
77 | elseif type(val) == "string" then | |
78 | str = '"' .. val:gsub("[%c\"\\]", controls) .. '"' | |
79 | -- Number encoding | |
80 | elseif type(val) == "number" or type(val) == "boolean" then | |
81 | str = tostring(val) | |
82 | else | |
83 | error("JSON only supports arrays, objects, numbers, booleans, and strings", 2) | |
84 | end | |
85 | return str | |
86 | end | |
87 | ||
88 | function encode(val) | |
89 | return encodeCommon(val, false, 0, {}) | |
90 | end | |
91 | ||
92 | function encodePretty(val) | |
93 | return encodeCommon(val, true, 0, {}) | |
94 | end | |
95 | ||
96 | ------------------------------------------------------------------ decoding | |
97 | ||
98 | local decodeControls = {} | |
99 | for k,v in pairs(controls) do | |
100 | decodeControls[v] = k | |
101 | end | |
102 | ||
103 | function parseBoolean(str) | |
104 | if str:sub(1, 4) == "true" then | |
105 | return true, removeWhite(str:sub(5)) | |
106 | else | |
107 | return false, removeWhite(str:sub(6)) | |
108 | end | |
109 | end | |
110 | ||
111 | function parseNull(str) | |
112 | return nil, removeWhite(str:sub(5)) | |
113 | end | |
114 | ||
115 | local numChars = {['e']=true; ['E']=true; ['+']=true; ['-']=true; ['.']=true} | |
116 | function parseNumber(str) | |
117 | local i = 1 | |
118 | while numChars[str:sub(i, i)] or tonumber(str:sub(i, i)) do | |
119 | i = i + 1 | |
120 | end | |
121 | local val = tonumber(str:sub(1, i - 1)) | |
122 | str = removeWhite(str:sub(i)) | |
123 | return val, str | |
124 | end | |
125 | ||
126 | function parseString(str) | |
127 | str = str:sub(2) | |
128 | local s = "" | |
129 | while str:sub(1,1) ~= "\"" do | |
130 | local next = str:sub(1,1) | |
131 | str = str:sub(2) | |
132 | assert(next ~= "\n", "Unclosed string") | |
133 | ||
134 | - | next = assert(decodeControls[next..escape], "Invalid escape character") |
134 | + | |
135 | local escape = str:sub(1,1) | |
136 | str = str:sub(2) | |
137 | ||
138 | -- Handle \uXXXX escapes. Probably wrongly, too! | |
139 | if escape == "u" then | |
140 | local escapeValue = str:sub(1, 4) | |
141 | str = str:sub(5) | |
142 | next = string.char(math.min(255, tonumber(escapeValue, 16))) | |
143 | else | |
144 | next = assert(decodeControls[next..escape], "Invalid escape " .. next .. escape) | |
145 | end | |
146 | end | |
147 | ||
148 | s = s .. next | |
149 | end | |
150 | return s, removeWhite(str:sub(2)) | |
151 | end | |
152 | ||
153 | function parseArray(str) | |
154 | str = removeWhite(str:sub(2)) | |
155 | ||
156 | local val = {} | |
157 | local i = 1 | |
158 | while str:sub(1, 1) ~= "]" do | |
159 | local v = nil | |
160 | v, str = parseValue(str) | |
161 | val[i] = v | |
162 | i = i + 1 | |
163 | str = removeWhite(str) | |
164 | end | |
165 | str = removeWhite(str:sub(2)) | |
166 | return val, str | |
167 | end | |
168 | ||
169 | function parseObject(str) | |
170 | str = removeWhite(str:sub(2)) | |
171 | ||
172 | local val = {} | |
173 | while str:sub(1, 1) ~= "}" do | |
174 | local k, v = nil, nil | |
175 | k, v, str = parseMember(str) | |
176 | val[k] = v | |
177 | str = removeWhite(str) | |
178 | end | |
179 | str = removeWhite(str:sub(2)) | |
180 | return val, str | |
181 | end | |
182 | ||
183 | function parseMember(str) | |
184 | local k = nil | |
185 | k, str = parseValue(str) | |
186 | local val = nil | |
187 | val, str = parseValue(str) | |
188 | return k, val, str | |
189 | end | |
190 | ||
191 | function parseValue(str) | |
192 | local fchar = str:sub(1, 1) | |
193 | if fchar == "{" then | |
194 | return parseObject(str) | |
195 | elseif fchar == "[" then | |
196 | return parseArray(str) | |
197 | elseif tonumber(fchar) ~= nil or numChars[fchar] then | |
198 | return parseNumber(str) | |
199 | elseif str:sub(1, 4) == "true" or str:sub(1, 5) == "false" then | |
200 | return parseBoolean(str) | |
201 | elseif fchar == "\"" then | |
202 | return parseString(str) | |
203 | elseif str:sub(1, 4) == "null" then | |
204 | return parseNull(str) | |
205 | end | |
206 | return nil | |
207 | end | |
208 | ||
209 | function decode(str) | |
210 | str = removeWhite(str) | |
211 | t = parseValue(str) | |
212 | return t | |
213 | end | |
214 | ||
215 | function decodeFromFile(path) | |
216 | local file = assert(fs.open(path, "r")) | |
217 | local decoded = decode(file.readAll()) | |
218 | file.close() | |
219 | return decoded | |
220 | end |