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Diffstat (limited to 'Data/BuiltIn/Libraries/json4lua/json/json.lua')
| -rw-r--r-- | Data/BuiltIn/Libraries/json4lua/json/json.lua | 427 |
1 files changed, 427 insertions, 0 deletions
diff --git a/Data/BuiltIn/Libraries/json4lua/json/json.lua b/Data/BuiltIn/Libraries/json4lua/json/json.lua new file mode 100644 index 0000000..79761b6 --- /dev/null +++ b/Data/BuiltIn/Libraries/json4lua/json/json.lua @@ -0,0 +1,427 @@ +-----------------------------------------------------------------------------
+-- JSON4Lua: JSON encoding / decoding support for the Lua language.
+-- json Module.
+-- Author: Craig Mason-Jones
+-- Homepage: http://github.com/craigmj/json4lua/
+-- Version: 1.0.0
+-- This module is released under the MIT License (MIT).
+-- Please see LICENCE.txt for details.
+--
+-- USAGE:
+-- This module exposes two functions:
+-- json.encode(o)
+-- Returns the table / string / boolean / number / nil / json.null value as a JSON-encoded string.
+-- json.decode(json_string)
+-- Returns a Lua object populated with the data encoded in the JSON string json_string.
+--
+-- REQUIREMENTS:
+-- compat-5.1 if using Lua 5.0
+--
+-- CHANGELOG
+-- 0.9.20 Introduction of local Lua functions for private functions (removed _ function prefix).
+-- Fixed Lua 5.1 compatibility issues.
+-- Introduced json.null to have null values in associative arrays.
+-- json.encode() performance improvement (more than 50%) through table.concat rather than ..
+-- Introduced decode ability to ignore /**/ comments in the JSON string.
+-- 0.9.10 Fix to array encoding / decoding to correctly manage nil/null values in arrays.
+-----------------------------------------------------------------------------
+
+-----------------------------------------------------------------------------
+-- Imports and dependencies
+-----------------------------------------------------------------------------
+local math = require('math')
+local string = require("string")
+local table = require("table")
+
+-----------------------------------------------------------------------------
+-- Module declaration
+-----------------------------------------------------------------------------
+local json = {} -- Public namespace
+local json_private = {} -- Private namespace
+
+-- Public constants
+json.EMPTY_ARRAY={}
+json.EMPTY_OBJECT={}
+
+-- Public functions
+
+-- Private functions
+local decode_scanArray
+local decode_scanComment
+local decode_scanConstant
+local decode_scanNumber
+local decode_scanObject
+local decode_scanString
+local decode_scanWhitespace
+local encodeString
+local isArray
+local isEncodable
+
+-----------------------------------------------------------------------------
+-- PUBLIC FUNCTIONS
+-----------------------------------------------------------------------------
+--- Encodes an arbitrary Lua object / variable.
+-- @param v The Lua object / variable to be JSON encoded.
+-- @return String containing the JSON encoding in internal Lua string format (i.e. not unicode)
+function json.encode (v)
+ -- Handle nil values
+ if v==nil then
+ return "null"
+ end
+
+ local vtype = type(v)
+
+ -- Handle strings
+ if vtype=='string' then
+ return '"' .. json_private.encodeString(v) .. '"' -- Need to handle encoding in string
+ end
+
+ -- Handle booleans
+ if vtype=='number' or vtype=='boolean' then
+ return tostring(v)
+ end
+
+ -- Handle tables
+ if vtype=='table' then
+ local rval = {}
+ -- Consider arrays separately
+ local bArray, maxCount = isArray(v)
+ if bArray then
+ for i = 1,maxCount do
+ table.insert(rval, json.encode(v[i]))
+ end
+ else -- An object, not an array
+ for i,j in pairs(v) do
+ if isEncodable(i) and isEncodable(j) then
+ table.insert(rval, '"' .. json_private.encodeString(i) .. '":' .. json.encode(j))
+ end
+ end
+ end
+ if bArray then
+ return '[' .. table.concat(rval,',') ..']'
+ else
+ return '{' .. table.concat(rval,',') .. '}'
+ end
+ end
+
+ -- Handle null values
+ if vtype=='function' and v==json.null then
+ return 'null'
+ end
+
+ assert(false,'encode attempt to encode unsupported type ' .. vtype .. ':' .. tostring(v))
+end
+
+
+--- Decodes a JSON string and returns the decoded value as a Lua data structure / value.
+-- @param s The string to scan.
+-- @param [startPos] Optional starting position where the JSON string is located. Defaults to 1.
+-- @param Lua object, number The object that was scanned, as a Lua table / string / number / boolean or nil,
+-- and the position of the first character after
+-- the scanned JSON object.
+function json.decode(s, startPos)
+ startPos = startPos and startPos or 1
+ startPos = decode_scanWhitespace(s,startPos)
+ assert(startPos<=string.len(s), 'Unterminated JSON encoded object found at position in [' .. s .. ']')
+ local curChar = string.sub(s,startPos,startPos)
+ -- Object
+ if curChar=='{' then
+ return decode_scanObject(s,startPos)
+ end
+ -- Array
+ if curChar=='[' then
+ return decode_scanArray(s,startPos)
+ end
+ -- Number
+ if string.find("+-0123456789.e", curChar, 1, true) then
+ return decode_scanNumber(s,startPos)
+ end
+ -- String
+ if curChar==[["]] or curChar==[[']] then
+ return decode_scanString(s,startPos)
+ end
+ if string.sub(s,startPos,startPos+1)=='/*' then
+ return json.decode(s, decode_scanComment(s,startPos))
+ end
+ -- Otherwise, it must be a constant
+ return decode_scanConstant(s,startPos)
+end
+
+--- The null function allows one to specify a null value in an associative array (which is otherwise
+-- discarded if you set the value with 'nil' in Lua. Simply set t = { first=json.null }
+function json.null()
+ return json.null -- so json.null() will also return null ;-)
+end
+-----------------------------------------------------------------------------
+-- Internal, PRIVATE functions.
+-- Following a Python-like convention, I have prefixed all these 'PRIVATE'
+-- functions with an underscore.
+-----------------------------------------------------------------------------
+
+--- Scans an array from JSON into a Lua object
+-- startPos begins at the start of the array.
+-- Returns the array and the next starting position
+-- @param s The string being scanned.
+-- @param startPos The starting position for the scan.
+-- @return table, int The scanned array as a table, and the position of the next character to scan.
+function decode_scanArray(s,startPos)
+ local array = {} -- The return value
+ local stringLen = string.len(s)
+ assert(string.sub(s,startPos,startPos)=='[','decode_scanArray called but array does not start at position ' .. startPos .. ' in string:\n'..s )
+ startPos = startPos + 1
+ -- Infinite loop for array elements
+ local index = 1
+ repeat
+ startPos = decode_scanWhitespace(s,startPos)
+ assert(startPos<=stringLen,'JSON String ended unexpectedly scanning array.')
+ local curChar = string.sub(s,startPos,startPos)
+ if (curChar==']') then
+ return array, startPos+1
+ end
+ if (curChar==',') then
+ startPos = decode_scanWhitespace(s,startPos+1)
+ end
+ assert(startPos<=stringLen, 'JSON String ended unexpectedly scanning array.')
+ object, startPos = json.decode(s,startPos)
+ array[index] = object
+ index = index + 1
+ until false
+end
+
+--- Scans a comment and discards the comment.
+-- Returns the position of the next character following the comment.
+-- @param string s The JSON string to scan.
+-- @param int startPos The starting position of the comment
+function decode_scanComment(s, startPos)
+ assert( string.sub(s,startPos,startPos+1)=='/*', "decode_scanComment called but comment does not start at position " .. startPos)
+ local endPos = string.find(s,'*/',startPos+2)
+ assert(endPos~=nil, "Unterminated comment in string at " .. startPos)
+ return endPos+2
+end
+
+--- Scans for given constants: true, false or null
+-- Returns the appropriate Lua type, and the position of the next character to read.
+-- @param s The string being scanned.
+-- @param startPos The position in the string at which to start scanning.
+-- @return object, int The object (true, false or nil) and the position at which the next character should be
+-- scanned.
+function decode_scanConstant(s, startPos)
+ local consts = { ["true"] = true, ["false"] = false, ["null"] = nil }
+ local constNames = {"true","false","null"}
+
+ for i,k in pairs(constNames) do
+ if string.sub(s,startPos, startPos + string.len(k) -1 )==k then
+ return consts[k], startPos + string.len(k)
+ end
+ end
+ assert(nil, 'Failed to scan constant from string ' .. s .. ' at starting position ' .. startPos)
+end
+
+--- Scans a number from the JSON encoded string.
+-- (in fact, also is able to scan numeric +- eqns, which is not
+-- in the JSON spec.)
+-- Returns the number, and the position of the next character
+-- after the number.
+-- @param s The string being scanned.
+-- @param startPos The position at which to start scanning.
+-- @return number, int The extracted number and the position of the next character to scan.
+function decode_scanNumber(s,startPos)
+ local endPos = startPos+1
+ local stringLen = string.len(s)
+ local acceptableChars = "+-0123456789.e"
+ while (string.find(acceptableChars, string.sub(s,endPos,endPos), 1, true)
+ and endPos<=stringLen
+ ) do
+ endPos = endPos + 1
+ end
+ local stringValue = 'return ' .. string.sub(s,startPos, endPos-1)
+ local stringEval = load(stringValue)
+ assert(stringEval, 'Failed to scan number [ ' .. stringValue .. '] in JSON string at position ' .. startPos .. ' : ' .. endPos)
+ return stringEval(), endPos
+end
+
+--- Scans a JSON object into a Lua object.
+-- startPos begins at the start of the object.
+-- Returns the object and the next starting position.
+-- @param s The string being scanned.
+-- @param startPos The starting position of the scan.
+-- @return table, int The scanned object as a table and the position of the next character to scan.
+function decode_scanObject(s,startPos)
+ local object = {}
+ local stringLen = string.len(s)
+ local key, value
+ assert(string.sub(s,startPos,startPos)=='{','decode_scanObject called but object does not start at position ' .. startPos .. ' in string:\n' .. s)
+ startPos = startPos + 1
+ repeat
+ startPos = decode_scanWhitespace(s,startPos)
+ assert(startPos<=stringLen, 'JSON string ended unexpectedly while scanning object.')
+ local curChar = string.sub(s,startPos,startPos)
+ if (curChar=='}') then
+ return object,startPos+1
+ end
+ if (curChar==',') then
+ startPos = decode_scanWhitespace(s,startPos+1)
+ end
+ assert(startPos<=stringLen, 'JSON string ended unexpectedly scanning object.')
+ -- Scan the key
+ key, startPos = json.decode(s,startPos)
+ assert(startPos<=stringLen, 'JSON string ended unexpectedly searching for value of key ' .. key)
+ startPos = decode_scanWhitespace(s,startPos)
+ assert(startPos<=stringLen, 'JSON string ended unexpectedly searching for value of key ' .. key)
+ assert(string.sub(s,startPos,startPos)==':','JSON object key-value assignment mal-formed at ' .. startPos)
+ startPos = decode_scanWhitespace(s,startPos+1)
+ assert(startPos<=stringLen, 'JSON string ended unexpectedly searching for value of key ' .. key)
+ value, startPos = json.decode(s,startPos)
+ object[key]=value
+ until false -- infinite loop while key-value pairs are found
+end
+
+-- START SoniEx2
+-- Initialize some things used by decode_scanString
+-- You know, for efficiency
+local escapeSequences = {
+ ["\\t"] = "\t",
+ ["\\f"] = "\f",
+ ["\\r"] = "\r",
+ ["\\n"] = "\n",
+ ["\\b"] = "\b"
+}
+setmetatable(escapeSequences, {__index = function(t,k)
+ -- skip "\" aka strip escape
+ return string.sub(k,2)
+end})
+-- END SoniEx2
+
+--- Scans a JSON string from the opening inverted comma or single quote to the
+-- end of the string.
+-- Returns the string extracted as a Lua string,
+-- and the position of the next non-string character
+-- (after the closing inverted comma or single quote).
+-- @param s The string being scanned.
+-- @param startPos The starting position of the scan.
+-- @return string, int The extracted string as a Lua string, and the next character to parse.
+function decode_scanString(s,startPos)
+ assert(startPos, 'decode_scanString(..) called without start position')
+ local startChar = string.sub(s,startPos,startPos)
+ -- START SoniEx2
+ -- PS: I don't think single quotes are valid JSON
+ assert(startChar == [["]] or startChar == [[']],'decode_scanString called for a non-string')
+ --assert(startPos, "String decoding failed: missing closing " .. startChar .. " for string at position " .. oldStart)
+ local t = {}
+ local i,j = startPos,startPos
+ while string.find(s, startChar, j+1) ~= j+1 do
+ local oldj = j
+ i,j = string.find(s, "\\.", j+1)
+ local x,y = string.find(s, startChar, oldj+1)
+ if not i or x < i then
+ i,j = x,y-1
+ end
+ table.insert(t, string.sub(s, oldj+1, i-1))
+ if string.sub(s, i, j) == "\\u" then
+ local a = string.sub(s,j+1,j+4)
+ j = j + 4
+ local n = tonumber(a, 16)
+ assert(n, "String decoding failed: bad Unicode escape " .. a .. " at position " .. i .. " : " .. j)
+ -- math.floor(x/2^y) == lazy right shift
+ -- a % 2^b == bitwise_and(a, (2^b)-1)
+ -- 64 = 2^6
+ -- 4096 = 2^12 (or 2^6 * 2^6)
+ local x
+ if n < 0x80 then
+ x = string.char(n % 0x80)
+ elseif n < 0x800 then
+ -- [110x xxxx] [10xx xxxx]
+ x = string.char(0xC0 + (math.floor(n/64) % 0x20), 0x80 + (n % 0x40))
+ else
+ -- [1110 xxxx] [10xx xxxx] [10xx xxxx]
+ x = string.char(0xE0 + (math.floor(n/4096) % 0x10), 0x80 + (math.floor(n/64) % 0x40), 0x80 + (n % 0x40))
+ end
+ table.insert(t, x)
+ else
+ table.insert(t, escapeSequences[string.sub(s, i, j)])
+ end
+ end
+ table.insert(t,string.sub(j, j+1))
+ assert(string.find(s, startChar, j+1), "String decoding failed: missing closing " .. startChar .. " at position " .. j .. "(for string at position " .. startPos .. ")")
+ return table.concat(t,""), j+2
+ -- END SoniEx2
+end
+
+--- Scans a JSON string skipping all whitespace from the current start position.
+-- Returns the position of the first non-whitespace character, or nil if the whole end of string is reached.
+-- @param s The string being scanned
+-- @param startPos The starting position where we should begin removing whitespace.
+-- @return int The first position where non-whitespace was encountered, or string.len(s)+1 if the end of string
+-- was reached.
+function decode_scanWhitespace(s,startPos)
+ local whitespace=" \n\r\t"
+ local stringLen = string.len(s)
+ while ( string.find(whitespace, string.sub(s,startPos,startPos), 1, true) and startPos <= stringLen) do
+ startPos = startPos + 1
+ end
+ return startPos
+end
+
+--- Encodes a string to be JSON-compatible.
+-- This just involves back-quoting inverted commas, back-quotes and newlines, I think ;-)
+-- @param s The string to return as a JSON encoded (i.e. backquoted string)
+-- @return The string appropriately escaped.
+
+local escapeList = {
+ ['"'] = '\\"',
+ ['\\'] = '\\\\',
+ ['/'] = '\\/',
+ ['\b'] = '\\b',
+ ['\f'] = '\\f',
+ ['\n'] = '\\n',
+ ['\r'] = '\\r',
+ ['\t'] = '\\t'
+}
+
+function json_private.encodeString(s)
+ local s = tostring(s)
+ return s:gsub(".", function(c) return escapeList[c] end) -- SoniEx2: 5.0 compat
+end
+
+-- Determines whether the given Lua type is an array or a table / dictionary.
+-- We consider any table an array if it has indexes 1..n for its n items, and no
+-- other data in the table.
+-- I think this method is currently a little 'flaky', but can't think of a good way around it yet...
+-- @param t The table to evaluate as an array
+-- @return boolean, number True if the table can be represented as an array, false otherwise. If true,
+-- the second returned value is the maximum
+-- number of indexed elements in the array.
+function isArray(t)
+ -- Next we count all the elements, ensuring that any non-indexed elements are not-encodable
+ -- (with the possible exception of 'n')
+ if (t == json.EMPTY_ARRAY) then return true, 0 end
+ if (t == json.EMPTY_OBJECT) then return false end
+
+ local maxIndex = 0
+ for k,v in pairs(t) do
+ if (type(k)=='number' and math.floor(k)==k and 1<=k) then -- k,v is an indexed pair
+ if (not isEncodable(v)) then return false end -- All array elements must be encodable
+ maxIndex = math.max(maxIndex,k)
+ else
+ if (k=='n') then
+ if v ~= (t.n or #t) then return false end -- False if n does not hold the number of elements
+ else -- Else of (k=='n')
+ if isEncodable(v) then return false end
+ end -- End of (k~='n')
+ end -- End of k,v not an indexed pair
+ end -- End of loop across all pairs
+ return true, maxIndex
+end
+
+--- Determines whether the given Lua object / table / variable can be JSON encoded. The only
+-- types that are JSON encodable are: string, boolean, number, nil, table and json.null.
+-- In this implementation, all other types are ignored.
+-- @param o The object to examine.
+-- @return boolean True if the object should be JSON encoded, false if it should be ignored.
+function isEncodable(o)
+ local t = type(o)
+ return (t=='string' or t=='boolean' or t=='number' or t=='nil' or t=='table') or
+ (t=='function' and o==json.null)
+end
+
+return json
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