bug fix in print to string code. it didn't work if the string being appended was larger than the chunk size.

added a unit test.

Author: jacobwilliams

src/json_value_module.F90

@@ -5702,7 +5702,9 @@ subroutine write_it(advance,comma,space_after_comma)
         logical(LK) :: add_comma       !! if a delimiter is to be added after string
         logical(LK) :: add_line_break  !! if a line break is to be added after string
         logical(LK) :: add_space       !! if a space is to be added after the comma
-        integer(IK) :: n               !! length of actual string appended to `str`
+        integer(IK) :: n               !! length of actual string `s` appended to `str`
+        integer(IK) :: room_left       !! number of characters left in `str`
+        integer(IK) :: n_chunks_to_add !! number of chunks to add to `str` for appending `s`
 
         if (present(comma)) then
             add_comma = comma
@@ -5752,9 +5754,11 @@ subroutine write_it(advance,comma,space_after_comma)
             if (add_line_break) s = s // newline
 
             n = len(s)
-            if (len(str)-iloc < n) then
+            room_left = len(str)-iloc
+            if (room_left < n) then
                 ! need to add another chunk to fit this string:
-                str = str // repeat(space, print_str_chunk_size)
+                n_chunks_to_add = max(1_IK, ceiling( real(len(s)-room_left,RK) / real(chunk_size,RK), IK ) )
+                str = str // repeat(space, print_str_chunk_size*n_chunks_to_add)
             end if
             ! append s to str:
             str(iloc+1:iloc+n-1) = s

src/tests/jf_test_36.F90

@@ -0,0 +1,78 @@
+!*****************************************************************************************
+!> author: Jacob Williams
+!  date: 1/15/2019
+!
+! Module for the 36th unit test.
+
+module jf_test_36_mod
+
+    use json_module
+    use, intrinsic :: iso_fortran_env , only: error_unit, output_unit
+
+    implicit none
+
+    private
+    public :: test_36
+
+contains
+
+    subroutine test_36(error_cnt)
+
+    !! Test writing a large JSON structure to a string.
+
+    implicit none
+
+    integer,intent(out) :: error_cnt !! report number of errors to caller
+
+    type(json_file) :: my_file
+    character(kind=json_CK,len=:),allocatable :: str_in, str_out
+
+    write(error_unit,'(A)') ''
+    write(error_unit,'(A)') '================================='
+    write(error_unit,'(A)') '   TEST 36'
+    write(error_unit,'(A)') '================================='
+    write(error_unit,'(A)') ''
+
+    error_cnt = 0
+
+    ! create a long string:
+    str_in = '{"long_string": "' // repeat('a', 10000) //'"}'
+
+    call my_file%initialize()
+
+    call my_file%load_from_string(str_in)
+
+    if (my_file%failed()) then
+        call my_file%print_error_message(error_unit)
+        error_cnt = error_cnt + 1
+    end if
+    call my_file%print_to_string(str_out)
+    if (my_file%failed()) then
+        call my_file%print_error_message(error_unit)
+        error_cnt = error_cnt + 1
+    end if
+
+    call my_file%destroy()
+
+    if (error_cnt==0) write(error_unit,'(A)') ' Success!'
+
+    end subroutine test_36
+
+end module jf_test_36_mod
+!*****************************************************************************************
+
+#ifndef INTERGATED_TESTS
+!*****************************************************************************************
+program jf_test_36
+
+    !! 36th unit test.
+
+    use jf_test_36_mod, only: test_36
+    implicit none
+    integer :: n_errors
+    call test_36(n_errors)
+    if ( n_errors /= 0) stop 1
+
+end program jf_test_36
+!*****************************************************************************************
+#endif

visual_studio/jsonfortrantest/jsonfortrantest.f90

@@ -42,6 +42,7 @@ program jsonfortrantest
     use jf_test_33_mod , only: test_33
     use jf_test_34_mod , only: test_34
     use jf_test_35_mod , only: test_35
+    use jf_test_36_mod , only: test_36
 
     implicit none
 
@@ -84,6 +85,7 @@ program jsonfortrantest
     call test_33(n_errors); if (n_errors /= 0) stop 1
     call test_34(n_errors); if (n_errors /= 0) stop 1
     call test_35(n_errors); if (n_errors /= 0) stop 1
+    call test_36(n_errors); if (n_errors /= 0) stop 1
 
     end program jsonfortrantest
 !*****************************************************************************************

visual_studio/jsonfortrantest/jsonfortrantest.vfproj

@@ -81,5 +81,6 @@
 		<File RelativePath="..\..\src\tests\jf_test_33.F90"/>
 		<File RelativePath="..\..\src\tests\jf_test_34.F90"/>
 		<File RelativePath="..\..\src\tests\jf_test_35.F90"/>
+		<File RelativePath="..\..\src\tests\jf_test_36.F90"/>
 		<File RelativePath=".\jsonfortrantest.f90"/></Filter></Files>
 	<Globals/></VisualStudioProject>