[Boost-bugs] [Boost C++ Libraries] #9495: property_tree json_read should accept iterators instead of just streams

Subject: [Boost-bugs] [Boost C++ Libraries] #9495: property_tree json_read should accept iterators instead of just streams
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-12-15 11:57:20

#9495: property_tree json_read should accept iterators instead of just streams
-----------------------------------------+---------------------------
 Reporter:  Egbert van der Wal <ewal@…>  |      Owner:  cornedbee
     Type:  Patches                      |     Status:  new
Milestone:  To Be Determined             |  Component:  property_tree
  Version:  Boost Development Trunk      |   Severity:  Optimization
 Keywords:                               |
-----------------------------------------+---------------------------
 For a project I am using boost::property_tree abundantly. The trees need
 to be transfered across all kinds of interfaces and I have ran the limited
 function call several times.

 It requires a istream to read from. To make matters worse, as soon as it
 enters the function, a complete copy is made to a vector. And that happens
 when I already had to make a copy because the read_json method expects to
 consume all input data, which rarely happens for me. I know the exact
 beginning and ending position in the stream, but there is no way to
 specify this.

 The following function signature would be prefered:

 {{{#!cpp
  template<typename Iterator, class Ptree>
     void read_json_internal(Iterator begin,
                             Iterator end,
                             Ptree &pt,
                             const std::string &filename)
 }}}

 This signature could still be used by the existing read_json_internal,
 which first converts this to a vector and then passed the vector iterators
 begin and and to this function, to avoid code duplication.

 Of course, the proper front-end in json_parser.hpp needs to be added to.

 The benefit is that this method can operate directly on my input sequence
 where I can specify exactly where the JSON states and where the JSON ends,
 avoiding all copies completely.

 I will attach a patch based on SVN Trunk that will accomplish this.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/9495>
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