util.json: Convert \uXXXX to UTF-8 when decoding

diff --git a/util/json.lua b/util/json.lua
index abb87eabe827456b2c916672e22afeebabb5ec55..ff7351a72f991dcb56ade78eb80c7d5e1153b8b3 100644 (file)
--- a/util/json.lua
+++ b/util/json.lua
@@ -1,3 +1,12 @@
+-- Prosody IM
+-- Copyright (C) 2008-2010 Matthew Wild
+-- Copyright (C) 2008-2010 Waqas Hussain
+--
+-- utf8char copyright (C) 2007 Rici Lake
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
 
 local type = type;
 local t_insert, t_concat, t_remove, t_sort = table.insert, table.concat, table.remove, table.sort;
@@ -29,6 +38,32 @@ for i=0,31 do
        if not escapes[ch] then escapes[ch] = ("\\u%.4X"):format(i); end
 end
 
+local function utf8char(i)
+       if i >= 0 then
+               i = i - i%1
+               if i < 128 then
+                       return s_char(i)
+               else
+                       local c1 = i % 64
+                       i = (i - c1) / 64
+                       if i < 32 then
+                               return s_char(0xC0+i, 0x80+c1)
+                       else
+                               local c2 = i % 64
+                               i = (i - c2) / 64
+                               if i < 16 and (i ~= 13 or c2 < 32) then
+                                       return s_char(0xE0+i, 0x80+c2, 0x80+c1)
+                               elseif i >= 16 and i < 0x110 then
+                                       local c3 = i % 64
+                                       i = (i - c3) / 64
+                                       return s_char(0xF0+i, 0x80+c3, 0x80+c2, 0x80+c1)
+                               end
+                       end
+               end
+       end
+end
+
+
 local valid_types = {
        number  = true,
        string  = true,
@@ -249,7 +284,7 @@ function json.decode(json)
                                                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
+                                       s = s..utf8char(tonumber(seq, 16));
                                        next();
                                else error("invalid escape sequence in string"); end
                        end