89 lines
2.5 KiB
Lua
89 lines
2.5 KiB
Lua
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--[[
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Licensed according to the included 'LICENSE' document
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Author: Thomas Harning Jr <harningt@gmail.com>
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]]
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local string_char = require("string").char
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local pairs = pairs
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local jsonutil = require("json.util")
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local util_merge = jsonutil.merge
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local _ENV = nil
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local normalEncodingMap = {
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['"'] = '\\"',
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['\\'] = '\\\\',
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['/'] = '\\/',
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['\b'] = '\\b',
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['\f'] = '\\f',
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['\n'] = '\\n',
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['\r'] = '\\r',
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['\t'] = '\\t',
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['\v'] = '\\v' -- not in official spec, on report, removing
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}
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local xEncodingMap = {}
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for char, encoded in pairs(normalEncodingMap) do
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xEncodingMap[char] = encoded
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end
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-- Pre-encode the control characters to speed up encoding...
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-- NOTE: UTF-8 may not work out right w/ JavaScript
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-- JavaScript uses 2 bytes after a \u... yet UTF-8 is a
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-- byte-stream encoding, not pairs of bytes (it does encode
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-- some letters > 1 byte, but base case is 1)
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for i = 0, 255 do
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local c = string_char(i)
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if c:match('[%z\1-\031\128-\255]') and not normalEncodingMap[c] then
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-- WARN: UTF8 specializes values >= 0x80 as parts of sequences...
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-- without \x encoding, do not allow encoding > 7F
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normalEncodingMap[c] = ('\\u%.4X'):format(i)
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xEncodingMap[c] = ('\\x%.2X'):format(i)
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end
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end
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local defaultOptions = {
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xEncode = false, -- Encode single-bytes as \xXX
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processor = nil, -- Simple processor for the string prior to quoting
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-- / is not required to be quoted but it helps with certain decoding
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-- Required encoded characters, " \, and 00-1F (0 - 31)
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encodeSet = '\\"/%z\1-\031',
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encodeSetAppend = nil -- Chars to append to the default set
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}
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local modeOptions = {}
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local function mergeOptions(options, mode)
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jsonutil.doOptionMerge(options, false, 'strings', defaultOptions, mode and modeOptions[mode])
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end
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local function getEncoder(options)
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options = options and util_merge({}, defaultOptions, options) or defaultOptions
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local encodeSet = options.encodeSet
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if options.encodeSetAppend then
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encodeSet = encodeSet .. options.encodeSetAppend
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end
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local encodingMap = options.xEncode and xEncodingMap or normalEncodingMap
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local encodeString
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if options.processor then
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local processor = options.processor
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encodeString = function(s, state)
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return '"' .. processor(s:gsub('[' .. encodeSet .. ']', encodingMap)) .. '"'
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end
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else
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encodeString = function(s, state)
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return '"' .. s:gsub('[' .. encodeSet .. ']', encodingMap) .. '"'
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end
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end
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return {
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string = encodeString
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}
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end
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local strings = {
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mergeOptions = mergeOptions,
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getEncoder = getEncoder
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}
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return strings
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