134 lines
3.6 KiB
Lua
134 lines
3.6 KiB
Lua
--[[
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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 lpeg = require("lpeg")
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local jsonutil = require("json.util")
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local util = require("json.decode.util")
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local merge = jsonutil.merge
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local tonumber = tonumber
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local string_char = require("string").char
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local floor = require("math").floor
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local table_concat = require("table").concat
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local error = error
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local _ENV = nil
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local function get_error(item)
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local fmt_string = item .. " in string [%q] @ %i:%i"
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return lpeg.P(function(data, index)
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local line, line_index, bad_char, last_line = util.get_invalid_character_info(data, index)
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local err = fmt_string:format(bad_char, line, line_index)
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error(err)
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end) * 1
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end
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local bad_unicode = get_error("Illegal unicode escape")
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local bad_hex = get_error("Illegal hex escape")
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local bad_character = get_error("Illegal character")
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local bad_escape = get_error("Illegal escape")
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local knownReplacements = {
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["'"] = "'",
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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',
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z = '\z'
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}
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-- according to the table at http://da.wikipedia.org/wiki/UTF-8
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local function utf8DecodeUnicode(code1, code2)
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code1, code2 = tonumber(code1, 16), tonumber(code2, 16)
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if code1 == 0 and code2 < 0x80 then
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return string_char(code2)
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end
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if code1 < 0x08 then
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return string_char(
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0xC0 + code1 * 4 + floor(code2 / 64),
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0x80 + code2 % 64)
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end
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return string_char(
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0xE0 + floor(code1 / 16),
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0x80 + (code1 % 16) * 4 + floor(code2 / 64),
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0x80 + code2 % 64)
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end
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local function decodeX(code)
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code = tonumber(code, 16)
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return string_char(code)
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end
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local doSimpleSub = lpeg.C(lpeg.S("'\"\\/bfnrtvz")) / knownReplacements
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local doUniSub = lpeg.P('u') * (lpeg.C(util.hexpair) * lpeg.C(util.hexpair) + bad_unicode)
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local doXSub = lpeg.P('x') * (lpeg.C(util.hexpair) + bad_hex)
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local defaultOptions = {
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badChars = '',
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additionalEscapes = false, -- disallow untranslated escapes
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escapeCheck = #lpeg.S('bfnrtv/\\"xu\'z'), -- no check on valid characters
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decodeUnicode = utf8DecodeUnicode,
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strict_quotes = false
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}
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local modeOptions = {}
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modeOptions.strict = {
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badChars = '\b\f\n\r\t\v',
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additionalEscapes = false, -- no additional escapes
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escapeCheck = #lpeg.S('bfnrtv/\\"u'), --only these chars are allowed to be escaped
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strict_quotes = true
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}
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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 buildCaptureString(quote, badChars, escapeMatch)
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local captureChar = (1 - lpeg.S("\\" .. badChars .. quote)) + (lpeg.P("\\") / "" * escapeMatch)
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-- During error, force end
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local captureString = captureChar^0 + (-#lpeg.P(quote) * bad_character + -1)
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return lpeg.P(quote) * lpeg.Cs(captureString) * lpeg.P(quote)
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end
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local function generateLexer(options)
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options = options.strings
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local quotes = { '"' }
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if not options.strict_quotes then
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quotes[#quotes + 1] = "'"
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end
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local escapeMatch = doSimpleSub
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escapeMatch = escapeMatch + doXSub / decodeX
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escapeMatch = escapeMatch + doUniSub / options.decodeUnicode
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if options.escapeCheck then
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escapeMatch = options.escapeCheck * escapeMatch + bad_escape
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end
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if options.additionalEscapes then
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escapeMatch = options.additionalEscapes + escapeMatch
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end
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local captureString
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for i = 1, #quotes do
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local cap = buildCaptureString(quotes[i], options.badChars, escapeMatch)
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if captureString == nil then
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captureString = cap
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else
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captureString = captureString + cap
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end
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end
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return captureString
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end
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local strings = {
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mergeOptions = mergeOptions,
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generateLexer = generateLexer
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}
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return strings
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