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1869 lines (1674 loc) · 67.3 KB
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-- -*- coding: utf-8 -*-
--
-- Simple JSON encoding and decoding in pure Lua.
--
-- Copyright 2010-2017 Jeffrey Friedl
-- http://regex.info/blog/
-- Latest version: http://regex.info/blog/lua/json
--
-- This code is released under a Creative Commons CC-BY "Attribution" License:
-- http://creativecommons.org/licenses/by/3.0/deed.en_US
--
-- It can be used for any purpose so long as:
-- 1) the copyright notice above is maintained
-- 2) the web-page links above are maintained
-- 3) the 'AUTHOR_NOTE' string below is maintained
--
local VERSION = '20211016.28' -- version history at end of file
local AUTHOR_NOTE = "-[ JSON.lua package by Jeffrey Friedl (http://regex.info/blog/lua/json) version 20211016.28 ]-"
--
-- The 'AUTHOR_NOTE' variable exists so that information about the source
-- of the package is maintained even in compiled versions. It's also
-- included in OBJDEF below mostly to quiet warnings about unused variables.
--
local OBJDEF = {
VERSION = VERSION,
AUTHOR_NOTE = AUTHOR_NOTE,
}
--
-- Simple JSON encoding and decoding in pure Lua.
-- JSON definition: http://www.json.org/
--
--
-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
--
-- local lua_value = JSON:decode(raw_json_text)
--
-- local raw_json_text = JSON:encode(lua_table_or_value)
-- local pretty_json_text = JSON:encode_pretty(lua_table_or_value) -- "pretty printed" version for human readability
--
--
--
-- DECODING (from a JSON string to a Lua table)
--
--
-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
--
-- local lua_value = JSON:decode(raw_json_text)
--
-- If the JSON text is for an object or an array, e.g.
-- { "what": "books", "count": 3 }
-- or
-- [ "Larry", "Curly", "Moe" ]
--
-- the result is a Lua table, e.g.
-- { what = "books", count = 3 }
-- or
-- { "Larry", "Curly", "Moe" }
--
--
-- The encode and decode routines accept an optional second argument,
-- "etc", which is not used during encoding or decoding, but upon error
-- is passed along to error handlers. It can be of any type (including nil).
--
--
--
-- ERROR HANDLING DURING DECODE
--
-- With most errors during decoding, this code calls
--
-- JSON:onDecodeError(message, text, location, etc)
--
-- with a message about the error, and if known, the JSON text being
-- parsed and the byte count where the problem was discovered. You can
-- replace the default JSON:onDecodeError() with your own function.
--
-- The default onDecodeError() merely augments the message with data
-- about the text and the location (and, an 'etc' argument had been
-- provided to decode(), its value is tacked onto the message as well),
-- and then calls JSON.assert(), which itself defaults to Lua's built-in
-- assert(), and can also be overridden.
--
-- For example, in an Adobe Lightroom plugin, you might use something like
--
-- function JSON:onDecodeError(message, text, location, etc)
-- LrErrors.throwUserError("Internal Error: invalid JSON data")
-- end
--
-- or even just
--
-- function JSON.assert(message)
-- LrErrors.throwUserError("Internal Error: " .. message)
-- end
--
-- If JSON:decode() is passed a nil, this is called instead:
--
-- JSON:onDecodeOfNilError(message, nil, nil, etc)
--
-- and if JSON:decode() is passed HTML instead of JSON, this is called:
--
-- JSON:onDecodeOfHTMLError(message, text, nil, etc)
--
-- The use of the 'etc' argument allows stronger coordination between
-- decoding and error reporting, especially when you provide your own
-- error-handling routines. Continuing with the the Adobe Lightroom
-- plugin example:
--
-- function JSON:onDecodeError(message, text, location, etc)
-- local note = "Internal Error: invalid JSON data"
-- if type(etc) = 'table' and etc.photo then
-- note = note .. " while processing for " .. etc.photo:getFormattedMetadata('fileName')
-- end
-- LrErrors.throwUserError(note)
-- end
--
-- :
-- :
--
-- for i, photo in ipairs(photosToProcess) do
-- :
-- :
-- local data = JSON:decode(someJsonText, { photo = photo })
-- :
-- :
-- end
--
--
--
-- If the JSON text passed to decode() has trailing garbage (e.g. as with the JSON "[123]xyzzy"),
-- the method
--
-- JSON:onTrailingGarbage(json_text, location, parsed_value, etc)
--
-- is invoked, where:
--
-- 'json_text' is the original JSON text being parsed,
-- 'location' is the count of bytes into 'json_text' where the garbage starts (6 in the example),
-- 'parsed_value' is the Lua result of what was successfully parsed ({123} in the example),
-- 'etc' is as above.
--
-- If JSON:onTrailingGarbage() does not abort, it should return the value decode() should return,
-- or nil + an error message.
--
-- local new_value, error_message = JSON:onTrailingGarbage()
--
-- The default JSON:onTrailingGarbage() simply invokes JSON:onDecodeError("trailing garbage"...),
-- but you can have this package ignore trailing garbage via
--
-- function JSON:onTrailingGarbage(json_text, location, parsed_value, etc)
-- return parsed_value
-- end
--
--
-- DECODING AND STRICT TYPES
--
-- Because both JSON objects and JSON arrays are converted to Lua tables,
-- it's not normally possible to tell which original JSON type a
-- particular Lua table was derived from, or guarantee decode-encode
-- round-trip equivalency.
--
-- However, if you enable strictTypes, e.g.
--
-- JSON = assert(loadfile "JSON.lua")() --load the routines
-- JSON.strictTypes = true
--
-- then the Lua table resulting from the decoding of a JSON object or
-- JSON array is marked via Lua metatable, so that when re-encoded with
-- JSON:encode() it ends up as the appropriate JSON type.
--
-- (This is not the default because other routines may not work well with
-- tables that have a metatable set, for example, Lightroom API calls.)
--
--
-- DECODING AND STRICT PARSING
--
-- If strictParsing is true in your JSON object, or if you set strictParsing as a decode option,
-- some kinds of technically-invalid JSON that would normally be accepted are rejected with an error.
--
-- For example, passing in an empty string
--
-- JSON:decode("")
--
-- normally succeeds with a return value of nil, but
--
-- JSON:decode("", nil, { strictParsing = true })
--
-- results in an error being raised (onDecodeError is called).
--
-- JSON.strictParsing = true
-- JSON:decode("")
--
-- achieves the same thing.
--
--
--
-- ENCODING (from a lua table to a JSON string)
--
-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
--
-- local raw_json_text = JSON:encode(lua_table_or_value)
-- local pretty_json_text = JSON:encode_pretty(lua_table_or_value) -- "pretty printed" version for human readability
-- local custom_pretty = JSON:encode(lua_table_or_value, etc, { pretty = true, indent = "| ", align_keys = false })
--
-- On error during encoding, this code calls:
--
-- JSON:onEncodeError(message, etc)
--
-- which you can override in your local JSON object. Also see "HANDLING UNSUPPORTED VALUE TYPES" below.
--
-- The 'etc' in the error call is the second argument to encode() and encode_pretty(), or nil if it wasn't provided.
--
--
--
--
-- ENCODING OPTIONS
--
-- An optional third argument, a table of options, can be provided to encode().
--
-- encode_options = {
-- -- options for making "pretty" human-readable JSON (see "PRETTY-PRINTING" below)
-- pretty = true, -- turn pretty formatting on
-- indent = " ", -- use this indent for each level of an array/object
-- align_keys = false, -- if true, align the keys in a way that sounds like it should be nice, but is actually ugly
-- array_newline = false, -- if true, array elements become one to a line rather than inline
--
-- -- other output-related options
-- null = "\0", -- see "ENCODING JSON NULL VALUES" below
-- stringsAreUtf8 = false, -- see "HANDLING UNICODE LINE AND PARAGRAPH SEPARATORS FOR JAVA" below
-- }
--
-- json_string = JSON:encode(mytable, etc, encode_options)
--
--
--
-- For reference, the defaults are:
--
-- pretty = false
-- null = nil,
-- stringsAreUtf8 = false,
--
--
--
-- PRETTY-PRINTING
--
-- Enabling the 'pretty' encode option helps generate human-readable JSON.
--
-- pretty = JSON:encode(val, etc, {
-- pretty = true,
-- indent = " ",
-- align_keys = false,
-- })
--
-- encode_pretty() is also provided: it's identical to encode() except
-- that encode_pretty() provides a default options table if none given in the call:
--
-- { pretty = true, indent = " ", align_keys = false, array_newline = false }
--
-- For example, if
--
-- JSON:encode(data)
--
-- produces:
--
-- {"city":"Kyoto","climate":{"avg_temp":16,"humidity":"high","snowfall":"minimal"},"country":"Japan","wards":11}
--
-- then
--
-- JSON:encode_pretty(data)
--
-- produces:
--
-- {
-- "city": "Kyoto",
-- "climate": {
-- "avg_temp": 16,
-- "humidity": "high",
-- "snowfall": "minimal"
-- },
-- "country": "Japan",
-- "wards": 11
-- }
--
-- The following lines all return identical strings:
-- JSON:encode_pretty(data)
-- JSON:encode_pretty(data, nil, { pretty = true, indent = " ", align_keys = false, array_newline = false})
-- JSON:encode_pretty(data, nil, { pretty = true, indent = " " })
-- JSON:encode (data, nil, { pretty = true, indent = " " })
--
-- An example of setting your own indent string:
--
-- JSON:encode_pretty(data, nil, { pretty = true, indent = "| " })
--
-- produces:
--
-- {
-- | "city": "Kyoto",
-- | "climate": {
-- | | "avg_temp": 16,
-- | | "humidity": "high",
-- | | "snowfall": "minimal"
-- | },
-- | "country": "Japan",
-- | "wards": 11
-- }
--
-- An example of setting align_keys to true:
--
-- JSON:encode_pretty(data, nil, { pretty = true, indent = " ", align_keys = true })
--
-- produces:
--
-- {
-- "city": "Kyoto",
-- "climate": {
-- "avg_temp": 16,
-- "humidity": "high",
-- "snowfall": "minimal"
-- },
-- "country": "Japan",
-- "wards": 11
-- }
--
-- which I must admit is kinda ugly, sorry. This was the default for
-- encode_pretty() prior to version 20141223.14.
--
--
-- HANDLING UNICODE LINE AND PARAGRAPH SEPARATORS FOR JAVA
--
-- If the 'stringsAreUtf8' encode option is set to true, consider Lua strings not as a sequence of bytes,
-- but as a sequence of UTF-8 characters.
--
-- Currently, the only practical effect of setting this option is that Unicode LINE and PARAGRAPH
-- separators, if found in a string, are encoded with a JSON escape instead of being dumped as is.
-- The JSON is valid either way, but encoding this way, apparently, allows the resulting JSON
-- to also be valid Java.
--
-- AMBIGUOUS SITUATIONS DURING THE ENCODING
--
-- During the encode, if a Lua table being encoded contains both string
-- and numeric keys, it fits neither JSON's idea of an object, nor its
-- idea of an array. To get around this, when any string key exists (or
-- when non-positive numeric keys exist), numeric keys are converted to
-- strings.
--
-- For example,
-- JSON:encode({ "one", "two", "three", SOMESTRING = "some string" }))
-- produces the JSON object
-- {"1":"one","2":"two","3":"three","SOMESTRING":"some string"}
--
-- To prohibit this conversion and instead make it an error condition, set
-- JSON.noKeyConversion = true
--
--
-- ENCODING JSON NULL VALUES
--
-- Lua tables completely omit keys whose value is nil, so without special handling there's
-- no way to represent JSON object's null value in a Lua table. For example
-- JSON:encode({ username = "admin", password = nil })
--
-- produces:
--
-- {"username":"admin"}
--
-- In order to actually produce
--
-- {"username":"admin", "password":null}
--
-- one can include a string value for a "null" field in the options table passed to encode()....
-- any Lua table entry with that value becomes null in the JSON output:
--
-- JSON:encode({ username = "admin", password = "xyzzy" }, -- First arg is the Lua table to encode as JSON.
-- nil, -- Second arg is the 'etc' value, ignored here
-- { null = "xyzzy" }) -- Third arg is th options table
--
-- produces:
--
-- {"username":"admin", "password":null}
--
-- Just be sure to use a string that is otherwise unlikely to appear in your data.
-- The string "\0" (a string with one null byte) may well be appropriate for many applications.
--
-- The "null" options also applies to Lua tables that become JSON arrays.
-- JSON:encode({ "one", "two", nil, nil })
--
-- produces
--
-- ["one","two"]
--
-- while
--
-- NullPlaceholder = "\0"
-- encode_options = { null = NullPlaceholder }
-- JSON:encode({ "one", "two", NullPlaceholder, NullPlaceholder}, nil, encode_options)
-- produces
--
-- ["one","two",null,null]
--
--
--
-- HANDLING LARGE AND/OR PRECISE NUMBERS
--
--
-- Without special handling, numbers in JSON can lose precision in Lua.
-- For example:
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- produces
--
-- small: number 12345
-- big: number 1.2345678901235e+28
-- precise: number 9876.6789012346
--
-- Precision is lost with both 'big' and 'precise'.
--
-- This package offers ways to try to handle this better (for some definitions of "better")...
--
-- The most precise method is by setting the global:
--
-- JSON.decodeNumbersAsObjects = true
--
-- When this is set, numeric JSON data is encoded into Lua in a form that preserves the exact
-- JSON numeric presentation when re-encoded back out to JSON, or accessed in Lua as a string.
--
-- This is done by encoding the numeric data with a Lua table/metatable that returns
-- the possibly-imprecise numeric form when accessed numerically, but the original precise
-- representation when accessed as a string.
--
-- Consider the example above, with this option turned on:
--
-- JSON.decodeNumbersAsObjects = true
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- This now produces:
--
-- small: table 12345
-- big: table 12345678901234567890123456789
-- precise: table 9876.67890123456789012345
--
-- However, within Lua you can still use the values (e.g. T.precise in the example above) in numeric
-- contexts. In such cases you'll get the possibly-imprecise numeric version, but in string contexts
-- and when the data finds its way to this package's encode() function, the original full-precision
-- representation is used.
--
-- You can force access to the string or numeric version via
-- JSON:forceString()
-- JSON:forceNumber()
-- For example,
-- local probably_okay = JSON:forceNumber(T.small) -- 'probably_okay' is a number
--
-- Code the inspects the JSON-turned-Lua data using type() can run into troubles because what used to
-- be a number can now be a table (e.g. as the small/big/precise example above shows). Update these
-- situations to use JSON:isNumber(item), which returns nil if the item is neither a number nor one
-- of these number objects. If it is either, it returns the number itself. For completeness there's
-- also JSON:isString(item).
--
-- If you want to try to avoid the hassles of this "number as an object" kludge for all but really
-- big numbers, you can set JSON.decodeNumbersAsObjects and then also set one or both of
-- JSON:decodeIntegerObjectificationLength
-- JSON:decodeDecimalObjectificationLength
-- They refer to the length of the part of the number before and after a decimal point. If they are
-- set and their part is at least that number of digits, objectification occurs. If both are set,
-- objectification occurs when either length is met.
--
-- -----------------------
--
-- Even without using the JSON.decodeNumbersAsObjects option, you can encode numbers in your Lua
-- table that retain high precision upon encoding to JSON, by using the JSON:asNumber() function:
--
-- T = {
-- imprecise = 123456789123456789.123456789123456789,
-- precise = JSON:asNumber("123456789123456789.123456789123456789")
-- }
--
-- print(JSON:encode_pretty(T))
--
-- This produces:
--
-- {
-- "precise": 123456789123456789.123456789123456789,
-- "imprecise": 1.2345678912346e+17
-- }
--
--
-- -----------------------
--
-- A different way to handle big/precise JSON numbers is to have decode() merely return the exact
-- string representation of the number instead of the number itself. This approach might be useful
-- when the numbers are merely some kind of opaque object identifier and you want to work with them
-- in Lua as strings anyway.
--
-- This approach is enabled by setting
--
-- JSON.decodeIntegerStringificationLength = 10
--
-- The value is the number of digits (of the integer part of the number) at which to stringify numbers.
-- NOTE: this setting is ignored if JSON.decodeNumbersAsObjects is true, as that takes precedence.
--
-- Consider our previous example with this option set to 10:
--
-- JSON.decodeIntegerStringificationLength = 10
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- This produces:
--
-- small: number 12345
-- big: string 12345678901234567890123456789
-- precise: number 9876.6789012346
--
-- The long integer of the 'big' field is at least JSON.decodeIntegerStringificationLength digits
-- in length, so it's converted not to a Lua integer but to a Lua string. Using a value of 0 or 1 ensures
-- that all JSON numeric data becomes strings in Lua.
--
-- Note that unlike
-- JSON.decodeNumbersAsObjects = true
-- this stringification is simple and unintelligent: the JSON number simply becomes a Lua string, and that's the end of it.
-- If the string is then converted back to JSON, it's still a string. After running the code above, adding
-- print(JSON:encode(T))
-- produces
-- {"big":"12345678901234567890123456789","precise":9876.6789012346,"small":12345}
-- which is unlikely to be desired.
--
-- There's a comparable option for the length of the decimal part of a number:
--
-- JSON.decodeDecimalStringificationLength
--
-- This can be used alone or in conjunction with
--
-- JSON.decodeIntegerStringificationLength
--
-- to trip stringification on precise numbers with at least JSON.decodeIntegerStringificationLength digits after
-- the decimal point. (Both are ignored if JSON.decodeNumbersAsObjects is true.)
--
-- This example:
--
-- JSON.decodeIntegerStringificationLength = 10
-- JSON.decodeDecimalStringificationLength = 5
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- produces:
--
-- small: number 12345
-- big: string 12345678901234567890123456789
-- precise: string 9876.67890123456789012345
--
--
-- HANDLING UNSUPPORTED VALUE TYPES
--
-- Among the encoding errors that might be raised is an attempt to convert a table value that has a type
-- that this package hasn't accounted for: a function, userdata, or a thread. You can handle these types as table
-- values (but not as table keys) if you supply a JSON:unsupportedTypeEncoder() method along the lines of the
-- following example:
--
-- function JSON:unsupportedTypeEncoder(value_of_unsupported_type)
-- if type(value_of_unsupported_type) == 'function' then
-- return "a function value"
-- else
-- return nil
-- end
-- end
--
-- Your unsupportedTypeEncoder() method is actually called with a bunch of arguments:
--
-- self:unsupportedTypeEncoder(value, parents, etc, options, indent, for_key)
--
-- The 'value' is the function, thread, or userdata to be converted to JSON.
--
-- The 'etc' and 'options' arguments are those passed to the original encode(). The other arguments are
-- probably of little interest; see the source code. (Note that 'for_key' is never true, as this function
-- is invoked only on table values; table keys of these types still trigger the onEncodeError method.)
--
-- If your unsupportedTypeEncoder() method returns a string, it's inserted into the JSON as is.
-- If it returns nil plus an error message, that error message is passed through to an onEncodeError invocation.
-- If it returns only nil, processing falls through to a default onEncodeError invocation.
--
-- If you want to handle everything in a simple way:
--
-- function JSON:unsupportedTypeEncoder(value)
-- return tostring(value)
-- end
--
--
-- SUMMARY OF METHODS YOU CAN OVERRIDE IN YOUR LOCAL LUA JSON OBJECT
--
-- assert
-- onDecodeError
-- onDecodeOfNilError
-- onDecodeOfHTMLError
-- onTrailingGarbage
-- onEncodeError
-- unsupportedTypeEncoder
--
-- If you want to create a separate Lua JSON object with its own error handlers,
-- you can reload JSON.lua or use the :new() method.
--
---------------------------------------------------------------------------
local default_pretty_indent = " "
local default_pretty_options = { pretty = true, indent = default_pretty_indent, align_keys = false, array_newline = false }
local isArray = { __tostring = function() return "JSON array" end } isArray.__index = isArray
local isObject = { __tostring = function() return "JSON object" end } isObject.__index = isObject
function OBJDEF:newArray(tbl)
return setmetatable(tbl or {}, isArray)
end
function OBJDEF:newObject(tbl)
return setmetatable(tbl or {}, isObject)
end
local function getnum(op)
return type(op) == 'number' and op or op.N
end
local isNumber = {
__tostring = function(T) return T.S end,
__unm = function(op) return getnum(op) end,
__concat = function(op1, op2) return tostring(op1) .. tostring(op2) end,
__add = function(op1, op2) return getnum(op1) + getnum(op2) end,
__sub = function(op1, op2) return getnum(op1) - getnum(op2) end,
__mul = function(op1, op2) return getnum(op1) * getnum(op2) end,
__div = function(op1, op2) return getnum(op1) / getnum(op2) end,
__mod = function(op1, op2) return getnum(op1) % getnum(op2) end,
__pow = function(op1, op2) return getnum(op1) ^ getnum(op2) end,
__lt = function(op1, op2) return getnum(op1) < getnum(op2) end,
__eq = function(op1, op2) return getnum(op1) == getnum(op2) end,
__le = function(op1, op2) return getnum(op1) <= getnum(op2) end,
}
isNumber.__index = isNumber
function OBJDEF:asNumber(item)
if getmetatable(item) == isNumber then
-- it's already a JSON number object.
return item
elseif type(item) == 'table' and type(item.S) == 'string' and type(item.N) == 'number' then
-- it's a number-object table that lost its metatable, so give it one
return setmetatable(item, isNumber)
else
-- the normal situation... given a number or a string representation of a number....
local holder = {
S = tostring(item), -- S is the representation of the number as a string, which remains precise
N = tonumber(item), -- N is the number as a Lua number.
}
return setmetatable(holder, isNumber)
end
end
--
-- Given an item that might be a normal string or number, or might be an 'isNumber' object defined above,
-- return the string version. This shouldn't be needed often because the 'isNumber' object should autoconvert
-- to a string in most cases, but it's here to allow it to be forced when needed.
--
function OBJDEF:forceString(item)
if type(item) == 'table' and type(item.S) == 'string' then
return item.S
else
return tostring(item)
end
end
--
-- Given an item that might be a normal string or number, or might be an 'isNumber' object defined above,
-- return the numeric version.
--
function OBJDEF:forceNumber(item)
if type(item) == 'table' and type(item.N) == 'number' then
return item.N
else
return tonumber(item)
end
end
--
-- If the given item is a number, return it. Otherwise, return nil.
-- This, this can be used both in a conditional and to access the number when you're not sure its form.
--
function OBJDEF:isNumber(item)
if type(item) == 'number' then
return item
elseif type(item) == 'table' and type(item.N) == 'number' then
return item.N
else
return nil
end
end
function OBJDEF:isString(item)
if type(item) == 'string' then
return item
elseif type(item) == 'table' and type(item.S) == 'string' then
return item.S
else
return nil
end
end
--
-- Some utf8 routines to deal with the fact that Lua handles only bytes
--
local function top_three_bits(val)
return math.floor(val / 0x20)
end
local function top_four_bits(val)
return math.floor(val / 0x10)
end
local function unicode_character_bytecount_based_on_first_byte(first_byte)
local W = string.byte(first_byte)
if W < 0x80 then
return 1
elseif (W == 0xC0) or (W == 0xC1) or (W >= 0x80 and W <= 0xBF) or (W >= 0xF5) then
-- this is an error -- W can't be the start of a utf8 character
return 0
elseif top_three_bits(W) == 0x06 then
return 2
elseif top_four_bits(W) == 0x0E then
return 3
else
return 4
end
end
local function unicode_codepoint_as_utf8(codepoint)
--
-- codepoint is a number
--
if codepoint <= 127 then
return string.char(codepoint)
elseif codepoint <= 2047 then
--
-- 110yyyxx 10xxxxxx <-- useful notation from http://en.wikipedia.org/wiki/Utf8
--
local highpart = math.floor(codepoint / 0x40)
local lowpart = codepoint - (0x40 * highpart)
return string.char(0xC0 + highpart,
0x80 + lowpart)
elseif codepoint <= 65535 then
--
-- 1110yyyy 10yyyyxx 10xxxxxx
--
local highpart = math.floor(codepoint / 0x1000)
local remainder = codepoint - 0x1000 * highpart
local midpart = math.floor(remainder / 0x40)
local lowpart = remainder - 0x40 * midpart
highpart = 0xE0 + highpart
midpart = 0x80 + midpart
lowpart = 0x80 + lowpart
--
-- Check for an invalid character (thanks Andy R. at Adobe).
-- See table 3.7, page 93, in http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf#G28070
--
if ( highpart == 0xE0 and midpart < 0xA0 ) or
( highpart == 0xED and midpart > 0x9F ) or
( highpart == 0xF0 and midpart < 0x90 ) or
( highpart == 0xF4 and midpart > 0x8F )
then
return "?"
else
return string.char(highpart,
midpart,
lowpart)
end
else
--
-- 11110zzz 10zzyyyy 10yyyyxx 10xxxxxx
--
local highpart = math.floor(codepoint / 0x40000)
local remainder = codepoint - 0x40000 * highpart
local midA = math.floor(remainder / 0x1000)
remainder = remainder - 0x1000 * midA
local midB = math.floor(remainder / 0x40)
local lowpart = remainder - 0x40 * midB
return string.char(0xF0 + highpart,
0x80 + midA,
0x80 + midB,
0x80 + lowpart)
end
end
function OBJDEF:onDecodeError(message, text, location, etc)
if text then
if location then
message = string.format("%s at byte %d of: %s", message, location, text)
else
message = string.format("%s: %s", message, text)
end
end
if etc ~= nil then
message = message .. " (" .. OBJDEF:encode(etc) .. ")"
end
if self.assert then
self.assert(false, message)
else
assert(false, message)
end
end
function OBJDEF:onTrailingGarbage(json_text, location, parsed_value, etc)
return self:onDecodeError("trailing garbage", json_text, location, etc)
end
OBJDEF.onDecodeOfNilError = OBJDEF.onDecodeError
OBJDEF.onDecodeOfHTMLError = OBJDEF.onDecodeError
function OBJDEF:onEncodeError(message, etc)
if etc ~= nil then
message = message .. " (" .. OBJDEF:encode(etc) .. ")"
end
if self.assert then
self.assert(false, message)
else
assert(false, message)
end
end
local function grok_number(self, text, start, options)
--
-- Grab the integer part
--
local integer_part = text:match('^-?[1-9]%d*', start)
or text:match("^-?0", start)
if not integer_part then
self:onDecodeError("expected number", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local i = start + integer_part:len()
--
-- Grab an optional decimal part
--
local decimal_part = text:match('^%.%d+', i) or ""
i = i + decimal_part:len()
--
-- Grab an optional exponential part
--
local exponent_part = text:match('^[eE][-+]?%d+', i) or ""
i = i + exponent_part:len()
local full_number_text = integer_part .. decimal_part .. exponent_part
if options.decodeNumbersAsObjects then
local objectify = false
if not options.decodeIntegerObjectificationLength and not options.decodeDecimalObjectificationLength then
-- no options, so objectify
objectify = true
elseif (options.decodeIntegerObjectificationLength
and
(integer_part:len() >= options.decodeIntegerObjectificationLength or exponent_part:len() > 0))
or
(options.decodeDecimalObjectificationLength
and
(decimal_part:len() >= options.decodeDecimalObjectificationLength or exponent_part:len() > 0))
then
-- have options and they are triggered, so objectify
objectify = true
end
if objectify then
return OBJDEF:asNumber(full_number_text), i
end
-- else, fall through to try to return as a straight-up number
else
-- Not always decoding numbers as objects, so perhaps encode as strings?
--
-- If we're told to stringify only under certain conditions, so do.
-- We punt a bit when there's an exponent by just stringifying no matter what.
-- I suppose we should really look to see whether the exponent is actually big enough one
-- way or the other to trip stringification, but I'll be lazy about it until someone asks.
--
if (options.decodeIntegerStringificationLength
and
(integer_part:len() >= options.decodeIntegerStringificationLength or exponent_part:len() > 0))
or
(options.decodeDecimalStringificationLength
and
(decimal_part:len() >= options.decodeDecimalStringificationLength or exponent_part:len() > 0))
then
return full_number_text, i -- this returns the exact string representation seen in the original JSON
end
end
local as_number = tonumber(full_number_text)
if not as_number then
self:onDecodeError("bad number", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
return as_number, i
end
local backslash_escape_conversion = {
['"'] = '"',
['/'] = "/",
['\\'] = "\\",
['b'] = "\b",
['f'] = "\f",
['n'] = "\n",
['r'] = "\r",
['t'] = "\t",
}
local function grok_string(self, text, start, options)
if text:sub(start,start) ~= '"' then
self:onDecodeError("expected string's opening quote", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local i = start + 1 -- +1 to bypass the initial quote
local text_len = text:len()
local VALUE = ""
while i <= text_len do
local c = text:sub(i,i)
if c == '"' then
return VALUE, i + 1
end
if c ~= '\\' then
-- should grab the next bytes as per the number of bytes for this utf8 character
local byte_count = unicode_character_bytecount_based_on_first_byte(c)
local next_character
if byte_count == 0 then
self:onDecodeError("non-utf8 sequence", text, i, options.etc)
elseif byte_count == 1 then
if options.strictParsing and string.byte(c) < 0x20 then
self:onDecodeError("Unescaped control character", text, i+1, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
next_character = c
elseif byte_count == 2 then
next_character = text:match('^(.[\128-\191])', i)
elseif byte_count == 3 then
next_character = text:match('^(.[\128-\191][\128-\191])', i)
elseif byte_count == 4 then
next_character = text:match('^(.[\128-\191][\128-\191][\128-\191])', i)
end
if not next_character then
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