A New JSON Library

Announcements
41

Nice! Latest on my laptop:

                       fson :   1.0140  seconds
                      rojff :   0.3662  seconds
               json_fortran :   0.1368  seconds
2 Likes
42

Interesting…maybe I was misremembering. I thought the stream read made a difference.

43

@everythingfunctional What is the minimum version of GFortran needed to compile this library?
GFortran 9.3.0 (the default version on Ubuntu 20.04 LTS) fails with the following error messages:

 + gfortran -c ././src/rojff/json_integer_m.f90  -Wall -Wextra -Wimplicit-interface -fPIC -fmax-errors=1 -g -fcheck=bounds -fcheck=array-temps -fbacktrace -fcoarray=single -J build/gfortran_2A42023B310FA28D/rojff -I build/gfortran_2A42023B310FA28D/rojff  -o build/gfortran_2A42023B310FA28D/rojff/src_rojff_json_integer_m.f90.o
././src/rojff/json_element_m.f90:36:24:

   36 |     recursive elemental function equals(lhs, rhs)
      |                        1
Error: ELEMENTAL attribute conflicts with RECURSIVE attribute at (1)
compilation terminated due to -fmax-errors=1.
././src/rojff/json_null_m.f90:50:37:

   50 |     subroutine write_to_expanded(self, indentation_level, sink)
      |                                     1
Warning: Unused dummy argument ‘self’ at (1) [-Wunused-dummy-argument]
././src/rojff/json_null_m.f90:43:38:

   43 |     subroutine write_to_compactly(self, sink)
      |                                      1
Warning: Unused dummy argument ‘self’ at (1) [-Wunused-dummy-argument]
././src/rojff/json_null_m.f90:30:33:

   30 |     elemental function equals(lhs, rhs)
      |                                 1
Warning: Unused dummy argument ‘lhs’ at (1) [-Wunused-dummy-argument]
././src/rojff/json_null_m.f90:20:44:

   20 |     function constructor() result(json_null)
      |                                            1
Warning: Return value ‘json_null’ of function ‘constructor’ declared at (1) not set [-Wreturn-type]
<ERROR> Compilation failed for object " src_rojff_json_element_m.f90.o "
<ERROR>stopping due to failed compilation
STOP 1

This is from using plain fpm build, btw. No additional options, no nothing.

44

Yeah, I ran into the same problem yesterday and had to make changes to my CI environment. 10 might work, but 11 definitely does.

45

I just tested with GFortran 10.3.0. Same error.

46

FYI: using strtod for the string to double conversion, and a few other minor tweaks, I’ve got JSON-Fortran parsing this canada.json file in 0.057 seconds with Gfortran 11.1. Amazing! Same order of magnitude as the python/C ones, although still not as fast, but a huge improvement from the read(fmt=*) version.

4 Likes
47

@jacobwilliams , would you care to try profiling of your JSON library now, say using Intel VTune Amplifier if gprof is suspect, to see what it might reveal to you on where the time is spent?

1 Like
48

I tried the same with my str2real function in your json-fortran:

original             : 0.117 s
str2real replacement : 0.051 s

I don’t know what your other tweaks did performance wise, but at least str2real seems to be competitive.

3 Likes