Embeded null written as \0 rather than \u0000 in property_tree::write_json

[Michael Anderson <drmikeando@…>]

Here's an example

#include "boost/property_tree/json_parser.hpp"
#include "boost/array.hpp"

int main()
{
  boost::property_tree::ptree pt;
  // Some random data to encode
  boost::array<unsigned char, 8> data = { 3,0,'W','A',0,'M',255,'z' };
  pt.put("binary", std::string(data.begin(), data.end() ) );
  boost::property_tree::write_json(std::cout, pt );
}

This produces the output

{
    "binary": "\u0003\0WA\0M\uFFFFz"
}

but from the description of JSON strings at ​http://www.json.org/ and the more detailed version at ​http://www.ietf.org/rfc/rfc4627.txt it would appear that the correct encoding of the 0 character is \u00000 rather than \0 ( which is correctly handled for other non-prinatable characters. )

[Michael Anderson <drmikeando@…>]

The fix is pretty easy, heres a patch from svn diff

===================================================================
--- boost/property_tree/detail/json_parser_write.hpp	(revision 58794)
+++ boost/property_tree/detail/json_parser_write.hpp	(working copy)
@@ -29,8 +29,7 @@
         typename std::basic_string<Ch>::const_iterator e = s.end();
         while (b != e)
         {
-            if (*b == Ch('\0')) result += Ch('\\'), result += Ch('0');
-            else if (*b == Ch('\b')) result += Ch('\\'), result += Ch('b');
+            if (*b == Ch('\b')) result += Ch('\\'), result += Ch('b');
             else if (*b == Ch('\f')) result += Ch('\\'), result += Ch('f');
             else if (*b == Ch('\n')) result += Ch('\\'), result += Ch('n');
             else if (*b == Ch('\r')) result += Ch('\\'), result += Ch('r');

[Sebastian Redl]

(In [59738]) Turns out JSON doesn't allow \0 as an escape sequence. Also, don't rely on is_print for figuring out which characters to escape, but instead follow the spec. Fixes bug 3827.