;+
; NAME:
;    FSC_BASE_FILENAME
;
; PURPOSE:
;
;    The purpose of this is to extract from a long file path, the
;    base file name. That is, the name of the actual file without
;    the preceeding directory information or the final file extension.
;    The directory information and file extension can be obtained via
;    keywords. The file is named so as not to interfere with FILE_BASENAME,
;    which was introduced in IDL 6.0 and performs a similar function.
;
; AUTHOR:
;
;   FANNING SOFTWARE CONSULTING
;   David Fanning, Ph.D.
;   1645 Sheely Drive
;   Fort Collins, CO 80526 USA
;   Phone: 970-221-0438
;   E-mail: davidf@dfanning.com
;   Coyote's Guide to IDL Programming: http://www.dfanning.com/
;
; CATEGORY:
;
;    Utility.
;
; CALLING SEQUENCE:
;
;    baseFilename = FSC_Base_Filename(thePath)
;
; INPUTS:
;
;    thePath:      This is the file path you wish to extract a base file name from.
;                  It is a string variable of the sort returned from Dialog_Pickfile.
;
; KEYWORDS:
;
;    DIRECTORY:      The directory information obtained from the input file path.
;                    The directory always ends in a directory separator character.
;
;    EXTENSION:      The file extension associated with the input file path.
;
;    PATH_SEPARATOR: The string to use as a path separator. If undefined, the output
;                    of PATH_SEP() will be used.
;
; RETURN_VALUE:
;
;    baseFilename:   The base filename, stripped of directory and file extension information.
;
; RESTRICTIONS:
;
;    This is a quick and dirty program. It has been tested on Windows machines and *lightly*
;    tested on UNIX machines. Please contact me at the e-mail address above if you discover
;    problems.
;
; EXAMPLE:
;
;    IDL> thePath = "C:\rsi\idl7.8\lib\jester.pro"
;    IDL> Print, FSC_Base_Filename(thePath, Directory=theDirectory, Extension=theExtension)
;         jester
;    IDL> Print, theDirectory
;         C:\rsi\idl7.8\lib\
;    IDL> Print, theExtension
;         pro
;
;
; MODIFICATION HISTORY:
;
;    Written by: David W. Fanning, 31 July 2003.
;    Modified by KaRo, 13 Feb. 2005 to allow dots in the filename.
;    Added PATH_SEPARATOR keyword. 25 July 2005. DWF.
;    Added ability to recongnize directory by path separator in last character. 19 Sept 2005. DWF.
;-
;###########################################################################
;
; LICENSE
;
; This software is OSI Certified Open Source Software.
; OSI Certified is a certification mark of the Open Source Initiative.
;
; Copyright © 2003-2005 Fanning Software Consulting
;
; This software is provided "as-is", without any express or
; implied warranty. In no event will the authors be held liable
; for any damages arising from the use of this software.
;
; Permission is granted to anyone to use this software for any
; purpose, including commercial applications, and to alter it and
; redistribute it freely, subject to the following restrictions:
;
; 1. The origin of this software must not be misrepresented; you must
;    not claim you wrote the original software. If you use this software
;    in a product, an acknowledgment in the product documentation
;    would be appreciated, but is not required.
;
; 2. Altered source versions must be plainly marked as such, and must
;    not be misrepresented as being the original software.
;
; 3. This notice may not be removed or altered from any source distribution.
;
; For more information on Open Source Software, visit the Open Source
; web site: http://www.opensource.org.
;
;###########################################################################


FUNCTION FSC_Base_Filename, filename, $
   Directory=directory, $
   Extension=extension, $
   Path_Separator=pathsep

   On_Error, 2

   ; Default values.
   directory = ""
   extension = ""
   file = ""

   ; If there is no filename, return NULL.
   IF (N_Elements(filename) EQ 0) OR (filename EQ "") THEN RETURN, file

   ; Is a path separator specified?
   IF N_Elements(pathsep) EQ 0 THEN pathsep = Path_Sep()

   ; If the last element of filename is a path separator, then separation is easy.
   IF StrMid(filename, StrLen(filename)-1, 1) EQ pathsep THEN BEGIN
      directory = filename
      RETURN, file
   ENDIF

   ; Split the file by the path separator and extract into parts.
   parts = StrSplit(filename, pathsep, /Extract)
   IF StrMid(filename, 0, 1) EQ pathsep AND N_Elements(parts) GT 1 THEN parts[0] = pathsep + parts[0]
   numParts = N_Elements(parts)

   ; Put the parts back together after identifying them.
   CASE numParts OF
      1: BEGIN
            subparts = StrSplit(filename, ".", /Extract)
            numsubParts = N_Elements(subparts)
            CASE numsubParts OF
               1: file = subparts[0]
               2: BEGIN
                     file = subparts[0]
                     extension = subparts[1]
                  END
               ELSE: BEGIN
                     file = StrJoin(subparts[0:numsubParts-2],'.')
                     extension = subparts[numsubParts-1]
                  END
            ENDCASE
         END

      2: BEGIN
            file = parts[1]
            directory = parts[0] + pathsep
            subparts = StrSplit(file, ".", /Extract)
            numsubParts = N_Elements(subparts)
            CASE numsubParts OF
               1: file = subparts[0]
               2: BEGIN
                     file = subparts[0]
                     extension = subparts[1]
                  END
               ELSE: BEGIN
                     file = StrJoin(subparts[0:numsubParts-2],'.')
                     extension = subparts[numsubParts-1]
                  END
            ENDCASE
         END

      ELSE: BEGIN

            file = parts[numParts-1]
            subparts = StrSplit(file, ".", /Extract)
            numsubParts = N_Elements(subparts)
            CASE numsubParts OF
               1: file = subparts[0]
               2: BEGIN
                     file = subparts[0]
                     extension = subparts[1]
                  END
               ELSE: BEGIN
                     file = StrJoin(subparts[0:numsubParts-2],'.')
                     extension = subparts[numsubParts-1]
                  END
            ENDCASE
            directory = parts[0]
            FOR j=1,numParts-2 DO BEGIN
               directory = directory + pathsep + parts[j]
            ENDFOR
            directory = directory + pathsep
         END

   ENDCASE

   RETURN, file

END