blob: f09255838b8f8feb4bca58dacbc0c396e3a3e123 [file] [log] [blame]
--[[
Licensed according to the included 'LICENSE' document
Author: Thomas Harning Jr <harningt@gmail.com>
]]
local lpeg = require("lpeg")
local util = require("json.decode.util")
local merge = require("json.util").merge
local tonumber = tonumber
local string_char = require("string").char
local floor = require("math").floor
local table_concat = require("table").concat
local error = error
module("json.decode.strings")
local function get_error(item)
local fmt_string = item .. " in string [%q] @ %i:%i"
return 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
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) + lpeg.P(bad_unicode))
local doXSub = lpeg.P('x') * (lpeg.C(util.hexpair) + lpeg.P(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
}
default = nil -- Let the buildCapture optimization take place
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 buildCaptureString(quote, badChars, escapeMatch)
local captureChar = (1 - lpeg.S("\\" .. badChars .. quote)) + (lpeg.P("\\") / "" * escapeMatch)
captureChar = captureChar + (-#lpeg.P(quote) * lpeg.P(bad_character))
local captureString = captureChar^0
return lpeg.P(quote) * lpeg.Cs(captureString) * lpeg.P(quote)
end
local function buildCapture(options)
options = options and merge({}, defaultOptions, options) or defaultOptions
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.additionalEscapes then
escapeMatch = escapeMatch + options.additionalEscapes
end
if options.escapeCheck then
escapeMatch = options.escapeCheck * escapeMatch + lpeg.P(bad_escape)
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
function register_types()
util.register_type("STRING")
end
function load_types(options, global_options, grammar)
local capture = buildCapture(options)
local string_id = util.types.STRING
grammar[string_id] = capture
util.append_grammar_item(grammar, "VALUE", lpeg.V(string_id))
end