[vlc-devel] [PATCH 2/6] lua:add dkjson
Rob Jonson
rob at hobbyistsoftware.com
Wed Sep 28 14:05:14 CEST 2011
---
share/Makefile.am | 2 +
share/lua/modules/dkjson.lua | 806 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 808 insertions(+), 0 deletions(-)
create mode 100644 share/lua/modules/dkjson.lua
diff --git a/share/Makefile.am b/share/Makefile.am
index ac6ed9c..0acb31f 100644
--- a/share/Makefile.am
+++ b/share/Makefile.am
@@ -149,6 +149,7 @@ nobase_vlclib_DATA = \
lua/meta/art/01_googleimage.luac \
lua/meta/fetcher/tvrage.luac \
lua/meta/reader/filename.luac \
+ lua/modules/dkjson.luac \
lua/modules/sandbox.luac \
lua/modules/simplexml.luac \
lua/playlist/anevia_streams.luac \
@@ -215,6 +216,7 @@ EXTRA_DIST += \
lua/meta/fetcher/tvrage.lua \
lua/meta/reader/README.txt \
lua/meta/reader/filename.lua \
+ lua/modules/dkjson.lua \
lua/modules/sandbox.lua \
lua/modules/simplexml.lua \
lua/playlist/README.txt \
diff --git a/share/lua/modules/dkjson.lua b/share/lua/modules/dkjson.lua
new file mode 100644
index 0000000..987587b
--- /dev/null
+++ b/share/lua/modules/dkjson.lua
@@ -0,0 +1,806 @@
+ --[==[
+
+David Kolf's JSON module for Lua 5.1/5.2
+========================================
+
+*Version 2.1*
+
+This module writes no global values, not even the module table.
+Import it using
+
+ json = require ("dkjson")
+
+Exported functions and values:
+
+`json.encode (object [, state])`
+--------------------------------
+
+Create a string representing the object. `Object` can be a table,
+a string, a number, a boolean, `nil`, `json.null` or any object with
+a function `__tojson` in its metatable. A table can only use strings
+and numbers as keys and its values have to be valid objects as
+well. It raises an error for any invalid data types or reference
+cycles.
+
+`state` is an optional table with the following fields:
+
+ - `indent`
+ When `indent` (a boolean) is set, the created string will contain
+ newlines and indentations. Otherwise it will be one long line.
+ - `keyorder`
+ `keyorder` is an array to specify the ordering of keys in the
+ encoded output. If an object has keys which are not in this array
+ they are written after the sorted keys.
+ - `level`
+ This is the initial level of indentation used when `indent` is
+ set. For each level two spaces are added. When absent it is set
+ to 0.
+ - `buffer`
+ `buffer` is an array to store the strings for the result so they
+ can be concatenated at once. When it isn't given, the encode
+ function will create it temporary and will return the
+ concatenated result.
+ - `bufferlen`
+ When `bufferlen` is set, it has to be the index of the last
+ element of `buffer`.
+ - `tables`
+ `tables` is a set to detect reference cycles. It is created
+ temporary when absent. Every table that is currently processed
+ is used as key, the value is `true`.
+
+When `state.buffer` was set, the return value will be `true` on
+success. Without `state.buffer` the return value will be a string.
+
+`json.decode (string [, position [, null]])`
+--------------------------------------------
+
+Decode `string` starting at `position` or at 1 if `position` was
+omitted.
+
+`null` is an optional value to be returned for null values. The
+default is `nil`, but you could set it to `json.null` or any other
+value.
+
+The return values are the object or `nil`, the position of the next
+character that doesn't belong to the object, and in case of errors
+an error message.
+
+Two metatables are created. Every array or object that is decoded gets
+a metatable with the `__jsontype` field set to either `array` or
+`object`. If you want to provide your own metatables use the syntax
+
+ json.decode (string, position, null, objectmeta, arraymeta)
+
+`<metatable>.__jsonorder`
+-------------------------
+
+`__jsonorder` can overwrite the `keyorder` for a specific table.
+
+`<metatable>.__jsontype`
+------------------------
+
+`__jsontype` can be either `"array"` or `"object"`. This is mainly useful
+for tables that can be empty. (The default for empty tables is
+`"array"`).
+
+`<metatable>.__tojson (self, state)`
+------------------------------------
+
+You can provide your own `__tojson` function in a metatable. In this
+function you can either add directly to the buffer and return true,
+or you can return a string. On errors nil and a message should be
+returned.
+
+`json.null`
+-----------
+
+You can use this value for setting explicit `null` values.
+
+`json.version`
+--------------
+
+Set to `"dkjson 2.1"`.
+
+`json.quotestring (string)`
+---------------------------
+
+Quote a UTF-8 string and escape critical characters using JSON
+escape sequences. This function is only necessary when you build
+your own `__tojson` functions.
+
+`json.addnewline (state)`
+-------------------------
+
+When `state.indent` is set, add a newline to `state.buffer` and spaces
+according to `state.level`.
+
+LPeg support
+------------
+
+When the local configuration variable
+`always_try_using_lpeg` is set, this module tries to load LPeg to
+replace the functions `quotestring` and `decode`. The speed increase
+is significant. You can get the LPeg module at
+ <http://www.inf.puc-rio.br/~roberto/lpeg/>.
+When LPeg couldn't be loaded, the pure Lua functions stay active.
+
+In case you don't want this module to require LPeg on its own,
+disable this option:
+
+ --]==]
+ local always_try_using_lpeg = true
+ --[==[
+
+In this case you can later load LPeg support using
+
+### `json.use_lpeg ()`
+
+Require the LPeg module and replace the functions `quotestring` and
+and `decode` with functions that use LPeg patterns.
+This function returns the module table, so you can load the module
+using:
+
+ json = require "dkjson".use_lpeg()
+
+Alternatively you can use `pcall` so the JSON module still works when
+LPeg isn't found.
+
+ json = require "dkjson"
+ pcall (json.use_lpeg)
+
+### `json.using_lpeg`
+
+This variable is set to `true` when LPeg was loaded successfully.
+
+You can contact the author by sending an e-mail to 'kolf' at the
+e-mail provider 'gmx.de'.
+
+---------------------------------------------------------------------
+
+*Copyright (C) 2010, 2011 David Heiko Kolf*
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+<!-- This documentation can be parsed using Markdown to generate HTML.
+ The source code is enclosed in a HTML comment so it won't be displayed
+ by browsers, but it should be removed from the final HTML file as
+ it isn't a valid HTML comment (and wastes space).
+ -->
+
+ <!--]==]
+
+-- global dependencies:
+local pairs, type, tostring, tonumber, getmetatable, setmetatable, rawset =
+ pairs, type, tostring, tonumber, getmetatable, setmetatable, rawset
+local error, require, pcall = error, require, pcall
+local floor, huge = math.floor, math.huge
+local strrep, gsub, strsub, strbyte, strchar, strfind, strlen, strformat =
+ string.rep, string.gsub, string.sub, string.byte, string.char,
+ string.find, string.len, string.format
+local concat = table.concat
+
+if _VERSION == 'Lua 5.1' then
+ local function noglobals (s,k,v) error ("global access: " .. k, 2) end
+ setfenv (1, setmetatable ({}, { __index = noglobals, __newindex = noglobals }))
+end
+local _ENV = nil -- blocking globals in Lua 5.2
+
+local json = { version = "dkjson 2.1" }
+
+pcall (function()
+ -- Enable access to blocked metatables.
+ -- Don't worry, this module doesn't change anything in them.
+ local debmeta = require "debug".getmetatable
+ if debmeta then getmetatable = debmeta end
+end)
+
+json.null = setmetatable ({}, {
+ __tojson = function () return "null" end
+})
+
+local function isarray (tbl)
+ local max, n, arraylen = 0, 0, 0
+ for k,v in pairs (tbl) do
+ if k == 'n' and type(v) == 'number' then
+ arraylen = v
+ if v > max then
+ max = v
+ end
+ else
+ if type(k) ~= 'number' or k < 1 or floor(k) ~= k then
+ return false
+ end
+ if k > max then
+ max = k
+ end
+ n = n + 1
+ end
+ end
+ if max > 10 and max > arraylen and max > n * 2 then
+ return false -- don't create an array with too many holes
+ end
+ return true, max
+end
+
+local escapecodes = {
+ ["\""] = "\\\"", ["\\"] = "\\\\", ["\b"] = "\\b", ["\f"] = "\\f",
+ ["\n"] = "\\n", ["\r"] = "\\r", ["\t"] = "\\t"
+}
+
+local function escapeutf8 (uchar)
+ local value = escapecodes[uchar]
+ if value then
+ return value
+ end
+ local a, b, c, d = strbyte (uchar, 1, 4)
+ a, b, c, d = a or 0, b or 0, c or 0, d or 0
+ if a <= 0x7f then
+ value = a
+ elseif 0xc0 <= a and a <= 0xdf and b >= 0x80 then
+ value = (a - 0xc0) * 0x40 + b - 0x80
+ elseif 0xe0 <= a and a <= 0xef and b >= 0x80 and c >= 0x80 then
+ value = ((a - 0xe0) * 0x40 + b - 0x80) * 0x40 + c - 0x80
+ elseif 0xf0 <= a and a <= 0xf7 and b >= 0x80 and c >= 0x80 and d >= 0x80 then
+ value = (((a - 0xf0) * 0x40 + b - 0x80) * 0x40 + c - 0x80) * 0x40 + d - 0x80
+ else
+ return ""
+ end
+ if value <= 0xffff then
+ return strformat ("\\u%.4x", value)
+ elseif value <= 0x10ffff then
+ -- encode as UTF-16 surrogate pair
+ value = value - 0x10000
+ local highsur, lowsur = 0xD800 + floor (value/0x400), 0xDC00 + (value % 0x400)
+ return strformat ("\\u%.4x\\u%.4x", highsur, lowsur)
+ else
+ return ""
+ end
+end
+
+local function fsub (str, pattern, repl)
+ -- gsub always builds a new string in a buffer, even when no match
+ -- exists. First using find should be more efficient when most strings
+ -- don't contain the pattern.
+ if strfind (str, pattern) then
+ return gsub (str, pattern, repl)
+ else
+ return str
+ end
+end
+
+local function quotestring (value)
+ -- based on the regexp "escapable" in https://github.com/douglascrockford/JSON-js
+ value = fsub (value, "[%z\1-\31\"\\\127]", escapeutf8)
+ if strfind (value, "[\194\216\220\225\226\239]") then
+ value = fsub (value, "\194[\128-\159\173]", escapeutf8)
+ value = fsub (value, "\216[\128-\132]", escapeutf8)
+ value = fsub (value, "\220\143", escapeutf8)
+ value = fsub (value, "\225\158[\180\181]", escapeutf8)
+ value = fsub (value, "\226\128[\140-\143\168\175]", escapeutf8)
+ value = fsub (value, "\226\129[\160-\175]", escapeutf8)
+ value = fsub (value, "\239\187\191", escapeutf8)
+ value = fsub (value, "\239\191[\176\191]", escapeutf8)
+ end
+ return "\"" .. value .. "\""
+end
+json.quotestring = quotestring
+
+local function addnewline2 (level, buffer, buflen)
+ buffer[buflen+1] = "\n"
+ buffer[buflen+2] = strrep (" ", level)
+ buflen = buflen + 2
+ return buflen
+end
+
+function json.addnewline (state)
+ if state.indent then
+ state.bufferlen = addnewline2 (state.level or 0,
+ state.buffer, state.bufferlen or #(state.buffer))
+ end
+end
+
+local encode2 -- forward declaration
+
+local function addpair (key, value, prev, indent, level, buffer, buflen, tables, globalorder)
+ local kt = type (key)
+ if kt ~= 'string' and kt ~= 'number' then
+ return nil, "type '" .. kt .. "' is not supported as a key by JSON."
+ end
+ if prev then
+ buflen = buflen + 1
+ buffer[buflen] = ","
+ end
+ if indent then
+ buflen = addnewline2 (level, buffer, buflen)
+ end
+ buffer[buflen+1] = quotestring (key)
+ buffer[buflen+2] = ":"
+ return encode2 (value, indent, level, buffer, buflen + 2, tables, globalorder)
+end
+
+encode2 = function (value, indent, level, buffer, buflen, tables, globalorder)
+ local valtype = type (value)
+ local valmeta = getmetatable (value)
+ valmeta = type (valmeta) == 'table' and valmeta -- only tables
+ local valtojson = valmeta and valmeta.__tojson
+ if valtojson then
+ if tables[value] then
+ return nil, "reference cycle"
+ end
+ tables[value] = true
+ local state = {
+ indent = indent, level = level, buffer = buffer,
+ bufferlen = buflen, tables = tables, keyorder = globalorder
+ }
+ local ret, msg = valtojson (value, state)
+ if not ret then return nil, msg end
+ tables[value] = nil
+ buflen = state.bufferlen
+ if type (ret) == 'string' then
+ buflen = buflen + 1
+ buffer[buflen] = ret
+ end
+ elseif value == nil then
+ buflen = buflen + 1
+ buffer[buflen] = "null"
+ elseif valtype == 'number' then
+ local s
+ if value ~= value or value >= huge or -value >= huge then
+ -- This is the behaviour of the original JSON implementation.
+ s = "null"
+ else
+ s = tostring (value)
+ end
+ buflen = buflen + 1
+ buffer[buflen] = s
+ elseif valtype == 'boolean' then
+ buflen = buflen + 1
+ buffer[buflen] = value and "true" or "false"
+ elseif valtype == 'string' then
+ buflen = buflen + 1
+ buffer[buflen] = quotestring (value)
+ elseif valtype == 'table' then
+ if tables[value] then
+ return nil, "reference cycle"
+ end
+ tables[value] = true
+ level = level + 1
+ local metatype = valmeta and valmeta.__jsontype
+ local isa, n
+ if metatype == 'array' then
+ isa = true
+ n = value.n or #value
+ elseif metatype == 'object' then
+ isa = false
+ else
+ isa, n = isarray (value)
+ end
+ local msg
+ if isa then -- JSON array
+ buflen = buflen + 1
+ buffer[buflen] = "["
+ for i = 1, n do
+ buflen, msg = encode2 (value[i], indent, level, buffer, buflen, tables, globalorder)
+ if not buflen then return nil, msg end
+ if i < n then
+ buflen = buflen + 1
+ buffer[buflen] = ","
+ end
+ end
+ buflen = buflen + 1
+ buffer[buflen] = "]"
+ else -- JSON object
+ local prev = false
+ buflen = buflen + 1
+ buffer[buflen] = "{"
+ local order = valmeta and valmeta.__jsonorder or globalorder
+ if order then
+ local used = {}
+ n = #order
+ for i = 1, n do
+ local k = order[i]
+ local v = value[k]
+ if v then
+ used[k] = true
+ buflen, msg = addpair (k, v, prev, indent, level, buffer, buflen, tables, globalorder)
+ prev = true -- add a seperator before the next element
+ end
+ end
+ for k,v in pairs (value) do
+ if not used[k] then
+ buflen, msg = addpair (k, v, prev, indent, level, buffer, buflen, tables, globalorder)
+ if not buflen then return nil, msg end
+ prev = true -- add a seperator before the next element
+ end
+ end
+ else -- unordered
+ for k,v in pairs (value) do
+ buflen, msg = addpair (k, v, prev, indent, level, buffer, buflen, tables, globalorder)
+ if not buflen then return nil, msg end
+ prev = true -- add a seperator before the next element
+ end
+ end
+ if indent then
+ buflen = addnewline2 (level - 1, buffer, buflen)
+ end
+ buflen = buflen + 1
+ buffer[buflen] = "}"
+ end
+ tables[value] = nil
+ else
+ return nil, "type '" .. valtype .. "' is not supported by JSON."
+ end
+ return buflen
+end
+
+function json.encode (value, state)
+ state = state or {}
+ local oldbuffer = state.buffer
+ local buffer = oldbuffer or {}
+ local ret, msg = encode2 (value, state.indent, state.level or 0,
+ buffer, state.bufferlen or 0, state.tables or {}, state.keyorder)
+ if not ret then
+ error (msg, 2)
+ elseif oldbuffer then
+ state.bufferlen = ret
+ return true
+ else
+ return concat (buffer)
+ end
+end
+
+local function loc (str, where)
+ local line, pos, linepos = 1, 1, 1
+ while true do
+ pos = strfind (str, "\n", pos, true)
+ if pos and pos < where then
+ line = line + 1
+ linepos = pos
+ pos = pos + 1
+ else
+ break
+ end
+ end
+ return "line " .. line .. ", column " .. (where - linepos)
+end
+
+local function unterminated (str, what, where)
+ return nil, strlen (str) + 1, "unterminated " .. what .. " at " .. loc (str, where)
+end
+
+local function scanwhite (str, pos)
+ while true do
+ pos = strfind (str, "%S", pos)
+ if not pos then return nil end
+ if strsub (str, pos, pos + 2) == "\239\187\191" then
+ -- UTF-8 Byte Order Mark
+ pos = pos + 3
+ else
+ return pos
+ end
+ end
+end
+
+local escapechars = {
+ ["\""] = "\"", ["\\"] = "\\", ["/"] = "/", ["b"] = "\b", ["f"] = "\f",
+ ["n"] = "\n", ["r"] = "\r", ["t"] = "\t"
+}
+
+local function unichar (value)
+ if value < 0 then
+ return nil
+ elseif value <= 0x007f then
+ return strchar (value)
+ elseif value <= 0x07ff then
+ return strchar (0xc0 + floor(value/0x40),
+ 0x80 + (floor(value) % 0x40))
+ elseif value <= 0xffff then
+ return strchar (0xe0 + floor(value/0x1000),
+ 0x80 + (floor(value/0x40) % 0x40),
+ 0x80 + (floor(value) % 0x40))
+ elseif value <= 0x10ffff then
+ return strchar (0xf0 + floor(value/0x40000),
+ 0x80 + (floor(value/0x1000) % 0x40),
+ 0x80 + (floor(value/0x40) % 0x40),
+ 0x80 + (floor(value) % 0x40))
+ else
+ return nil
+ end
+end
+
+local function scanstring (str, pos)
+ local lastpos = pos + 1
+ local buffer, n = {}, 0
+ while true do
+ local nextpos = strfind (str, "[\"\\]", lastpos)
+ if not nextpos then
+ return unterminated (str, "string", pos)
+ end
+ if nextpos > lastpos then
+ n = n + 1
+ buffer[n] = strsub (str, lastpos, nextpos - 1)
+ end
+ if strsub (str, nextpos, nextpos) == "\"" then
+ lastpos = nextpos + 1
+ break
+ else
+ local escchar = strsub (str, nextpos + 1, nextpos + 1)
+ local value
+ if escchar == "u" then
+ value = tonumber (strsub (str, nextpos + 2, nextpos + 5), 16)
+ if value then
+ local value2
+ if 0xD800 <= value and value <= 0xDBff then
+ -- we have the high surrogate of UTF-16. Check if there is a
+ -- low surrogate escaped nearby to combine them.
+ if strsub (str, nextpos + 6, nextpos + 7) == "\\u" then
+ value2 = tonumber (strsub (str, nextpos + 8, nextpos + 11), 16)
+ if value2 and 0xDC00 <= value2 and value2 <= 0xDFFF then
+ value = (value - 0xD800) * 0x400 + (value2 - 0xDC00) + 0x10000
+ else
+ value2 = nil -- in case it was out of range for a low surrogate
+ end
+ end
+ end
+ value = value and unichar (value)
+ if value then
+ if value2 then
+ lastpos = nextpos + 12
+ else
+ lastpos = nextpos + 6
+ end
+ end
+ end
+ end
+ if not value then
+ value = escapechars[escchar] or escchar
+ lastpos = nextpos + 2
+ end
+ n = n + 1
+ buffer[n] = value
+ end
+ end
+ if n == 1 then
+ return buffer[1], lastpos
+ elseif n > 1 then
+ return concat (buffer), lastpos
+ else
+ return "", lastpos
+ end
+end
+
+local scanvalue -- forward declaration
+
+local function scantable (what, closechar, str, startpos, nullval, objectmeta, arraymeta)
+ local len = strlen (str)
+ local tbl, n = {}, 0
+ local pos = startpos + 1
+ if what == 'object' then
+ setmetatable (tbl, objectmeta)
+ else
+ setmetatable (tbl, arraymeta)
+ end
+ while true do
+ pos = scanwhite (str, pos)
+ if not pos then return unterminated (str, what, startpos) end
+ local char = strsub (str, pos, pos)
+ if char == closechar then
+ return tbl, pos + 1
+ end
+ local val1, err
+ val1, pos, err = scanvalue (str, pos, nullval, objectmeta, arraymeta)
+ if err then return nil, pos, err end
+ pos = scanwhite (str, pos)
+ if not pos then return unterminated (str, what, startpos) end
+ char = strsub (str, pos, pos)
+ if char == ":" then
+ if val1 == nil then
+ return nil, pos, "cannot use nil as table index (at " .. loc (str, pos) .. ")"
+ end
+ pos = scanwhite (str, pos + 1)
+ if not pos then return unterminated (str, what, startpos) end
+ local val2
+ val2, pos, err = scanvalue (str, pos, nullval, objectmeta, arraymeta)
+ if err then return nil, pos, err end
+ tbl[val1] = val2
+ pos = scanwhite (str, pos)
+ if not pos then return unterminated (str, what, startpos) end
+ char = strsub (str, pos, pos)
+ else
+ n = n + 1
+ tbl[n] = val1
+ end
+ if char == "," then
+ pos = pos + 1
+ end
+ end
+end
+
+scanvalue = function (str, pos, nullval, objectmeta, arraymeta)
+ pos = pos or 1
+ pos = scanwhite (str, pos)
+ if not pos then
+ return nil, strlen (str) + 1, "no valid JSON value (reached the end)"
+ end
+ local char = strsub (str, pos, pos)
+ if char == "{" then
+ return scantable ('object', "}", str, pos, nullval, objectmeta, arraymeta)
+ elseif char == "[" then
+ return scantable ('array', "]", str, pos, nullval, objectmeta, arraymeta)
+ elseif char == "\"" then
+ return scanstring (str, pos)
+ else
+ local pstart, pend = strfind (str, "^%-?[%d%.]+[eE]?[%+%-]?%d*", pos)
+ if pstart then
+ local number = tonumber (strsub (str, pstart, pend))
+ if number then
+ return number, pend + 1
+ end
+ end
+ pstart, pend = strfind (str, "^%a%w*", pos)
+ if pstart then
+ local name = strsub (str, pstart, pend)
+ if name == "true" then
+ return true, pend + 1
+ elseif name == "false" then
+ return false, pend + 1
+ elseif name == "null" then
+ return nullval, pend + 1
+ end
+ end
+ return nil, pos, "no valid JSON value at " .. loc (str, pos)
+ end
+end
+
+function json.decode (str, pos, nullval, objectmeta, arraymeta)
+ objectmeta = objectmeta or {__jsontype = 'object'}
+ arraymeta = arraymeta or {__jsontype = 'array'}
+ return scanvalue (str, pos, nullval, objectmeta, arraymeta)
+end
+
+function json.use_lpeg ()
+ local g = require ("lpeg")
+ local pegmatch = g.match
+ local P, S, R, V = g.P, g.S, g.R, g.V
+
+ local SpecialChars = (R"\0\31" + S"\"\\\127" +
+ P"\194" * (R"\128\159" + P"\173") +
+ P"\216" * R"\128\132" +
+ P"\220\132" +
+ P"\225\158" * S"\180\181" +
+ P"\226\128" * (R"\140\143" + S"\168\175") +
+ P"\226\129" * R"\160\175" +
+ P"\239\187\191" +
+ P"\229\191" + R"\176\191") / escapeutf8
+
+ local QuoteStr = g.Cs (g.Cc "\"" * (SpecialChars + 1)^0 * g.Cc "\"")
+
+ quotestring = function (str)
+ return pegmatch (QuoteStr, str)
+ end
+ json.quotestring = quotestring
+
+ local function ErrorCall (str, pos, msg, state)
+ if not state.msg then
+ state.msg = msg .. " at " .. loc (str, pos)
+ state.pos = pos
+ end
+ return false
+ end
+
+ local function Err (msg)
+ return g.Cmt (g.Cc (msg) * g.Carg (2), ErrorCall)
+ end
+
+ local Space = (S" \n\r\t" + P"\239\187\191")^0
+
+ local PlainChar = 1 - S"\"\\\n\r"
+ local EscapeSequence = (P"\\" * g.C (S"\"\\/bfnrt" + Err "unsupported escape sequence")) / escapechars
+ local HexDigit = R("09", "af", "AF")
+ local function UTF16Surrogate (match, pos, high, low)
+ high, low = tonumber (high, 16), tonumber (low, 16)
+ if 0xD800 <= high and high <= 0xDBff and 0xDC00 <= low and low <= 0xDFFF then
+ return true, unichar ((high - 0xD800) * 0x400 + (low - 0xDC00) + 0x10000)
+ else
+ return false
+ end
+ end
+ local function UTF16BMP (hex)
+ return unichar (tonumber (hex, 16))
+ end
+ local U16Sequence = (P"\\u" * g.C (HexDigit * HexDigit * HexDigit * HexDigit))
+ local UnicodeEscape = g.Cmt (U16Sequence * U16Sequence, UTF16Surrogate) + U16Sequence/UTF16BMP
+ local Char = UnicodeEscape + EscapeSequence + PlainChar
+ local String = P"\"" * g.Cs (Char ^ 0) * (P"\"" + Err "unterminated string")
+ local Integer = P"-"^(-1) * (P"0" + (R"19" * R"09"^0))
+ local Fractal = P"." * R"09"^0
+ local Exponent = (S"eE") * (S"+-")^(-1) * R"09"^1
+ local Number = (Integer * Fractal^(-1) * Exponent^(-1))/tonumber
+ local Constant = P"true" * g.Cc (true) + P"false" * g.Cc (false) + P"null" * g.Carg (1)
+ local SimpleValue = Number + String + Constant
+ local ArrayContent, ObjectContent
+
+ -- The functions parsearray and parseobject parse only a single value/pair
+ -- at a time and store them directly to avoid hitting the LPeg limits.
+ local function parsearray (str, pos, nullval, state)
+ local obj, cont
+ local npos
+ local t, nt = {}, 0
+ repeat
+ obj, cont, npos = pegmatch (ArrayContent, str, pos, nullval, state)
+ if not npos then break end
+ pos = npos
+ nt = nt + 1
+ t[nt] = obj
+ until cont == 'last'
+ return pos, setmetatable (t, state.arraymeta)
+ end
+
+ local function parseobject (str, pos, nullval, state)
+ local obj, key, cont
+ local npos
+ local t = {}
+ repeat
+ key, obj, cont, npos = pegmatch (ObjectContent, str, pos, nullval, state)
+ if not npos then break end
+ pos = npos
+ t[key] = obj
+ until cont == 'last'
+ return pos, setmetatable (t, state.objectmeta)
+ end
+
+ local Array = P"[" * g.Cmt (g.Carg(1) * g.Carg(2), parsearray) * Space * (P"]" + Err "']' expected")
+ local Object = P"{" * g.Cmt (g.Carg(1) * g.Carg(2), parseobject) * Space * (P"}" + Err "'}' expected")
+ local Value = Space * (Array + Object + SimpleValue)
+ local ExpectedValue = Value + Space * Err "value expected"
+ ArrayContent = Value * Space * (P"," * g.Cc'cont' + g.Cc'last') * g.Cp()
+ local Pair = g.Cg (Space * String * Space * (P":" + Err "colon expected") * ExpectedValue)
+ ObjectContent = Pair * Space * (P"," * g.Cc'cont' + g.Cc'last') * g.Cp()
+ local DecodeValue = ExpectedValue * g.Cp ()
+
+ function json.decode (str, pos, nullval, objectmeta, arraymeta)
+ local state = {
+ objectmeta = objectmeta or {__jsontype = 'object'},
+ arraymeta = arraymeta or {__jsontype = 'array'}
+ }
+ local obj, retpos = pegmatch (DecodeValue, str, pos, nullval, state)
+ if state.msg then
+ return nil, state.pos, state.msg
+ else
+ return obj, retpos
+ end
+ end
+
+ -- use this function only once:
+ json.use_lpeg = function () return json end
+
+ json.using_lpeg = true
+
+ return json -- so you can get the module using json = require "dkjson".use_lpeg()
+end
+
+if always_try_using_lpeg then
+ pcall (json.use_lpeg)
+end
+
+return json
+
+-->
--
1.7.5
More information about the vlc-devel
mailing list