add json_parse.pro for compatibility prior to v8.2

json_parse.pro

@@ -0,0 +1,93 @@
+; $Id: //depot/InDevelopment/scrums/ENVI_Yukon/idl/idldir/lib/idl_base64.pro#3 $
+;
+; Copyright (c) 2012-2015, Exelis Visual Information Solutions, Inc. All
+;       rights reserved. Unauthorized reproduction is prohibited.
+;
+;----------------------------------------------------------------------------
+;+
+; :Description:
+;    The JSON_PARSE function takes a JSON string and converts it into
+;    an IDL variable.
+;
+; :Returns:
+;    If *String* begins with a curly brace "{", then the result is
+;    a HASH, containing the unordered name-value pairs from the JSON string.
+;    If *String* begins with a square bracket "[", then the result is
+;    a LIST, containing the ordered collection of values.
+;    If *String* is a scalar string that does not begin with "{" or "[",
+;    then it is assumed to be a file name. If the file exists, then the
+;    contents of the file are read and parsed.
+;
+;    *Note*: When converting JSON strings into IDL variables,
+;    the following rules are used:
+;      "null" becomes !NULL.
+;      "false" becomes byte 0, "true" becomes byte 1.
+;      Integer values become IDL variables of type LONG64.
+;      Floating-point numbers become IDL variables of type DOUBLE.
+;      Strings will be converted to IDL strings, and all \ escaped characters
+;      will be converted back to normal characters.
+;      JSON arrays will become IDL LIST variables.
+;      JSON objects will become IDL HASH variables.
+;   
+;    *Note*: Since the HASH stores its name-value pairs in an arbitrary
+;    order, the HASH::Keys() method may return the name-value pairs
+;    in a different order compared to the original JSON string.
+;   
+; :Params:
+;    String:
+;      *String* must be a valid JSON string containing either a
+;      JSON *object* of name-value pairs, or a JSON *array* of values.
+;
+; :Keywords:
+;    None
+;
+;
+; :Author:
+;   CT, VIS, Jan 2012. Based on the IDLffJSON, written by Dawn Lenz.
+;-
+function JSON_Parse, String, DEBUG=debug, _EXTRA=extra
+
+  compile_opt idl2, hidden
+
+  if (~KEYWORD_SET(debug)) then begin
+    ON_ERROR, 2
+    ; Catch errors from our method and fake the call stack.
+    CATCH, iErr
+    if (iErr ne 0) then begin
+      CATCH, /CANCEL
+      MESSAGE, !ERROR_STATE.msg
+    endif
+  endif
+
+  ; Make sure the object definition is compiled, in case this
+  ; will be included in save files.
+  IDLffJSON__Define
+
+  ; See if our input is actually a file name.
+  if (ISA(String, 'STRING', /SCALAR)) then begin
+
+    char = STRMID(String, 0, 1)
+    if (char ne '"' && char ne '[' && char ne '{') then begin
+
+      if (FILE_TEST(String, /READ) && QUERY_ASCII(String, info)) then begin
+        data = STRARR(info.lines)
+        OPENR, lun, String, /GET_LUN
+        READF, lun, data
+        FREE_LUN, lun
+        obj = OBJ_NEW("IDLffJSON")
+        result = obj->Parse(STRJOIN(data), DEBUG=debug, _STRICT_EXTRA=extra)
+        OBJ_DESTROY, obj
+        return, result
+      endif
+
+    endif
+
+  endif
+
+
+  obj = OBJ_NEW("IDLffJSON")
+  result = obj->Parse(String, DEBUG=debug, _STRICT_EXTRA=extra)
+  OBJ_DESTROY, obj
+  return, result
+end
+