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-rw-r--r--util/json.lua358
1 files changed, 358 insertions, 0 deletions
diff --git a/util/json.lua b/util/json.lua
new file mode 100644
index 00000000..05453703
--- /dev/null
+++ b/util/json.lua
@@ -0,0 +1,358 @@
+
+local type = type;
+local t_insert, t_concat, t_remove = table.insert, table.concat, table.remove;
+local s_char = string.char;
+local tostring, tonumber = tostring, tonumber;
+local pairs, ipairs = pairs, ipairs;
+local next = next;
+local error = error;
+local newproxy, getmetatable = newproxy, getmetatable;
+local print = print;
+
+--module("json")
+local json = {};
+
+local null = newproxy and newproxy(true) or {};
+if getmetatable and getmetatable(null) then
+ getmetatable(null).__tostring = function() return "null"; end;
+end
+json.null = null;
+
+local escapes = {
+ ["\""] = "\\\"", ["\\"] = "\\\\", ["\b"] = "\\b",
+ ["\f"] = "\\f", ["\n"] = "\\n", ["\r"] = "\\r", ["\t"] = "\\t"};
+local unescapes = {
+ ["\""] = "\"", ["\\"] = "\\", ["/"] = "/",
+ b = "\b", f = "\f", n = "\n", r = "\r", t = "\t"};
+for i=0,31 do
+ local ch = s_char(i);
+ if not escapes[ch] then escapes[ch] = ("\\u%.4X"):format(i); end
+end
+
+local valid_types = {
+ number = true,
+ string = true,
+ table = true,
+ boolean = true
+};
+local special_keys = {
+ __array = true;
+ __hash = true;
+};
+
+local simplesave, tablesave, arraysave, stringsave;
+
+function stringsave(o, buffer)
+ -- FIXME do proper utf-8 and binary data detection
+ t_insert(buffer, "\""..(o:gsub(".", escapes)).."\"");
+end
+
+function arraysave(o, buffer)
+ t_insert(buffer, "[");
+ if next(o) then
+ for i,v in ipairs(o) do
+ simplesave(v, buffer);
+ t_insert(buffer, ",");
+ end
+ t_remove(buffer);
+ end
+ t_insert(buffer, "]");
+end
+
+function tablesave(o, buffer)
+ local __array = {};
+ local __hash = {};
+ local hash = {};
+ for i,v in ipairs(o) do
+ __array[i] = v;
+ end
+ for k,v in pairs(o) do
+ local ktype, vtype = type(k), type(v);
+ if valid_types[vtype] or v == null then
+ if ktype == "string" and not special_keys[k] then
+ hash[k] = v;
+ elseif (valid_types[ktype] or k == null) and __array[k] == nil then
+ __hash[k] = v;
+ end
+ end
+ end
+ if next(__hash) ~= nil or next(hash) ~= nil or next(__array) == nil then
+ t_insert(buffer, "{");
+ local mark = #buffer;
+ for k,v in pairs(hash) do
+ stringsave(k, buffer);
+ t_insert(buffer, ":");
+ simplesave(v, buffer);
+ t_insert(buffer, ",");
+ end
+ if next(__hash) ~= nil then
+ t_insert(buffer, "\"__hash\":[");
+ for k,v in pairs(__hash) do
+ simplesave(k, buffer);
+ t_insert(buffer, ",");
+ simplesave(v, buffer);
+ t_insert(buffer, ",");
+ end
+ t_remove(buffer);
+ t_insert(buffer, "]");
+ t_insert(buffer, ",");
+ end
+ if next(__array) then
+ t_insert(buffer, "\"__array\":");
+ arraysave(__array, buffer);
+ t_insert(buffer, ",");
+ end
+ if mark ~= #buffer then t_remove(buffer); end
+ t_insert(buffer, "}");
+ else
+ arraysave(__array, buffer);
+ end
+end
+
+function simplesave(o, buffer)
+ local t = type(o);
+ if t == "number" then
+ t_insert(buffer, tostring(o));
+ elseif t == "string" then
+ stringsave(o, buffer);
+ elseif t == "table" then
+ tablesave(o, buffer);
+ elseif t == "boolean" then
+ t_insert(buffer, (o and "true" or "false"));
+ else
+ t_insert(buffer, "null");
+ end
+end
+
+function json.encode(obj)
+ local t = {};
+ simplesave(obj, t);
+ return t_concat(t);
+end
+
+-----------------------------------
+
+
+function json.decode(json)
+ local pos = 1;
+ local current = {};
+ local stack = {};
+ local ch, peek;
+ local function next()
+ ch = json:sub(pos, pos);
+ pos = pos+1;
+ peek = json:sub(pos, pos);
+ return ch;
+ end
+
+ local function skipwhitespace()
+ while ch and (ch == "\r" or ch == "\n" or ch == "\t" or ch == " ") do
+ next();
+ end
+ end
+ local function skiplinecomment()
+ repeat next(); until not(ch) or ch == "\r" or ch == "\n";
+ skipwhitespace();
+ end
+ local function skipstarcomment()
+ next(); next(); -- skip '/', '*'
+ while peek and ch ~= "*" and peek ~= "/" do next(); end
+ if not peek then error("eof in star comment") end
+ next(); next(); -- skip '*', '/'
+ skipwhitespace();
+ end
+ local function skipstuff()
+ while true do
+ skipwhitespace();
+ if ch == "/" and peek == "*" then
+ skipstarcomment();
+ elseif ch == "/" and peek == "*" then
+ skiplinecomment();
+ else
+ return;
+ end
+ end
+ end
+
+ local readvalue;
+ local function readarray()
+ local t = {};
+ next(); -- skip '['
+ skipstuff();
+ if ch == "]" then next(); return t; end
+ t_insert(t, readvalue());
+ while true do
+ skipstuff();
+ if ch == "]" then next(); return t; end
+ if not ch then error("eof while reading array");
+ elseif ch == "," then next();
+ elseif ch then error("unexpected character in array, comma expected"); end
+ if not ch then error("eof while reading array"); end
+ t_insert(t, readvalue());
+ end
+ end
+
+ local function checkandskip(c)
+ local x = ch or "eof";
+ if x ~= c then error("unexpected "..x..", '"..c.."' expected"); end
+ next();
+ end
+ local function readliteral(lit, val)
+ for c in lit:gmatch(".") do
+ checkandskip(c);
+ end
+ return val;
+ end
+ local function readstring()
+ local s = "";
+ checkandskip("\"");
+ while ch do
+ while ch and ch ~= "\\" and ch ~= "\"" do
+ s = s..ch; next();
+ end
+ if ch == "\\" then
+ next();
+ if unescapes[ch] then
+ s = s..unescapes[ch];
+ next();
+ elseif ch == "u" then
+ local seq = "";
+ for i=1,4 do
+ next();
+ if not ch then error("unexpected eof in string"); end
+ if not ch:match("[0-9a-fA-F]") then error("invalid unicode escape sequence in string"); end
+ seq = seq..ch;
+ end
+ s = s..s.char(tonumber(seq, 16)); -- FIXME do proper utf-8
+ next();
+ else error("invalid escape sequence in string"); end
+ end
+ if ch == "\"" then
+ next();
+ return s;
+ end
+ end
+ error("eof while reading string");
+ end
+ local function readnumber()
+ local s = "";
+ if ch == "-" then
+ s = s..ch; next();
+ if not ch:match("[0-9]") then error("number format error"); end
+ end
+ if ch == "0" then
+ s = s..ch; next();
+ if ch:match("[0-9]") then error("number format error"); end
+ else
+ while ch and ch:match("[0-9]") do
+ s = s..ch; next();
+ end
+ end
+ if ch == "." then
+ s = s..ch; next();
+ if not ch:match("[0-9]") then error("number format error"); end
+ while ch and ch:match("[0-9]") do
+ s = s..ch; next();
+ end
+ if ch == "e" or ch == "E" then
+ s = s..ch; next();
+ if ch == "+" or ch == "-" then
+ s = s..ch; next();
+ if not ch:match("[0-9]") then error("number format error"); end
+ while ch and ch:match("[0-9]") do
+ s = s..ch; next();
+ end
+ end
+ end
+ end
+ return tonumber(s);
+ end
+ local function readmember(t)
+ skipstuff();
+ local k = readstring();
+ skipstuff();
+ checkandskip(":");
+ t[k] = readvalue();
+ end
+ local function fixobject(obj)
+ local __array = obj.__array;
+ if __array then
+ obj.__array = nil;
+ for i,v in ipairs(__array) do
+ t_insert(obj, v);
+ end
+ end
+ local __hash = obj.__hash;
+ if __hash then
+ obj.__hash = nil;
+ local k;
+ for i,v in ipairs(__hash) do
+ if k ~= nil then
+ obj[k] = v; k = nil;
+ else
+ k = v;
+ end
+ end
+ end
+ return obj;
+ end
+ local function readobject()
+ local t = {};
+ next(); -- skip '{'
+ skipstuff();
+ if ch == "}" then next(); return t; end
+ if not ch then error("eof while reading object"); end
+ readmember(t);
+ while true do
+ skipstuff();
+ if ch == "}" then next(); return fixobject(t); end
+ if not ch then error("eof while reading object");
+ elseif ch == "," then next();
+ elseif ch then error("unexpected character in object, comma expected"); end
+ if not ch then error("eof while reading object"); end
+ readmember(t);
+ end
+ end
+
+ function readvalue()
+ skipstuff();
+ while ch do
+ if ch == "{" then
+ return readobject();
+ elseif ch == "[" then
+ return readarray();
+ elseif ch == "\"" then
+ return readstring();
+ elseif ch:match("[%-0-9%.]") then
+ return readnumber();
+ elseif ch == "n" then
+ return readliteral("null", null);
+ elseif ch == "t" then
+ return readliteral("true", true);
+ elseif ch == "f" then
+ return readliteral("false", false);
+ else
+ error("invalid character at value start: "..ch);
+ end
+ end
+ error("eof while reading value");
+ end
+ next();
+ return readvalue();
+end
+
+function json.test(object)
+ local encoded = json.encode(object);
+ local decoded = json.decode(encoded);
+ local recoded = json.encode(decoded);
+ if encoded ~= recoded then
+ print("FAILED");
+ print("encoded:", encoded);
+ print("recoded:", recoded);
+ else
+ print(encoded);
+ end
+ return encoded == recoded;
+end
+
+return json;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-08 11:33:46 +0000