swade-fr-content/tools/luajson/json/decode/strings.lua

134 lines
3.6 KiB
Lua

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