Approach to Archive Programs in PDF and Retrieve Programs from PDF Files

Transcription

1 Paper PO18 Approach to Archive Programs in PDF and Retrieve Programs from PDF Files Eric Zhang, Centocor Research & Development, Inc., Malvern, PA Leah Bednarek, Centocor Research & Development, Inc., Malvern, PA Daniel Hofstaedter, Centocor Research & Development, Inc., Malvern, PA ABSTRACT Quite often, once a project has been completed, SAS programmers are faced with the need to archive their programs. Ideally, the program files should be (1) easily archived, (2) protected from unauthorized changes and (3) easily retrieved from archive, in their original format. Storing SAS programs in PDF format is one of the most effective and efficient ways to achieve all three of these objectives. A new approach was developed for this purpose. The capabilities, features, and usage of the approach are described in the paper. INTRODUCTION There are many tools available to convert SAS programs to PDF files and to retrieve SAS programs back from PDF files. However, most available tools have been developed outside SAS and are difficult to modify for our industry specific requirements. And in many cases, the retrieved SAS programs do not have the exact same format and layout as the original SAS programs. An approach was developed, entirely in SAS, in order to overcome both of these obstacles. Using this new approach, the converted SAS programs have the specific features we need and the retrieved SAS programs are identical to the originals. The approach does not rely on the third party software and works well across any platform where SAS can be used. APPROACH The approach utilizes two SAS macros, both of which incorporate PDF PostScript language. The first macro, SAS2PDF, has the ability to convert a single SAS program, or multiple SAS programs, from a designated directory, into a single PDF file, sorted and bookmarked by the names of the archived SAS programs. As with any bookmarked PDF file, the user can open the file in Acrobat Reader, click a program s bookmark in the left window and then browse the contents of that program in the right window. The second macro, PDF2SAS, will convert these archived SAS programs from PDF, back into their original format. The user has the option to select a single bookmark (SAS program), or multiple bookmarks (SAS programs). The retrieved SAS programs will have the original program names and the exact same contents and layouts they had prior to archival. In addition, macro PDF2SAS provides the user with the option of executing SAS programs from the PDF file in SAS Editor window directly instead of retrieving them to a physical folder. Before saving the archived PDF file and deleting the original SAS programs, users should make sure that the tobe-retrieved SAS programs from the archived PDF file would be the same as the original SAS programs. Users should create a temporary folder, retrieve SAS programs from the PDF file, save them in the temporary folder, and then compare them with the original SAS programs. The macro VALOFPDF is developed for this comparison. A PDF FILE AND ITS STRUCTURE PDF relies on the imaging model of PostScript page description language to describe text and graphics in a device-independent and resolution-independent manner. PDF defines a more structured format than that used by 1

2 most PostScript language programs. A PDF file (PDF version 1.2) always starts with the following codes: %PDF-1.2 %âãïó OBJECTS OF A PDF FILE A PDF file is object-structured and has many objects: information object, catalog object, page object, font object, encoding object, stream object, and so on. The objects of PDF are labeled by positive integers starting from 1. The labels start from one and consecutively continue to the number of the last object. PDF can access objects randomly and the order of the objects occurrence in a PDF file has no semantic significance. In general, it s not necessary to put numbered objects in numerical order when creating a PDF file, i.e., object 2 can follow object 4 in a PDF file. When a PDF file is viewed in Acrobat Reader, Acrobat Reader will automatically identify objects of the PDF file and display contents of the PDF file. The following example shows an object of a PDF file: 25 0 OBJ INFORMATION OBJECT The information object normally follows the two beginning statements of a PDF file immediately and identifies the information of the PDF file. The following code shows the information object in a PDF file that is generated by macro SAS2PDF: 1 0 OBJ /Author (Eric Zhang) /CreationDate (D: ) /Creator (SAS2PDF.SAS) /Producer (Centocor && Inc.) /Title (programs.pdf) /Subject (Convert SAS programs to a PDF file) The catalog object contains references to other objects defining the document s contents, outline, article threads, named destinations, and other attributes, i.e., the page object and other objects. The catalog object defined in macro SAS2PDF contains the reference to the page object only. The page object defines pages of a PDF file. The catalog object follows the information object and the page object follows the catalog object. The catalog object and page object outline the structure of pages of a PDF file. PAGE OBJECT A PDF file has a page object that defines object references, which contain text strings in pages. As an example, the following page object defines a PDF file with nine pages and its nine stream object references. 4 0 OBJ /Type /Pages /Count 9 /MediaBox [ ] /Kids [ 2

3 11 0 R 14 0 R 17 0 R 20 0 R 23 0 R 26 0 R 29 0 R 32 0 R 35 0 R ] FONT OBJECT The font object is a text object. It controls fonts and styles of text strings when a PDF file is viewed in Acrobat Reader. The font object has a couple of font types in PDF. The font object in the macros uses Type1 font type, which defines glyph shapes by using a special encoded format. This font type contains entries of Type1 font dictionary. The entries are Subtype, Name, Encoding and BaseFont. The following codes are used in the macros to define a font object. Using this example code, the characters in a PDF file viewed in Acrobat Reader would have Courier font with regular, italic, bold, and bold italic styles, and would be encoded in the encoding object OBJ /Type /Font /Subtype /Type1 /Name /F1 /Encoding R /BaseFont /Courier OBJ /Type /Font /Subtype /Type1 /Name /F2 /Encoding R /BaseFont /Courier-Oblique OBJ /Type /Font /Subtype /Type1 /Name /F3 /Encoding R /BaseFont /Courier-Bold OBJ /Type /Font /Subtype /Type1 /Name /F4 /Encoding R 3

4 /BaseFont /Courier-BoldOblique ENCODING OBJECT PDF needs to use one of the encoding formats that will translate characters in a PDF file to device-based characters. After encoding, contents of a PDF file can be viewed in Acrobat Reader. Macro SAS2PDF uses the following subset of Latin Character Set and the corresponding encoding. This character set includes all the characters SAS programs use OBJ /Type /Encoding /Differences [ 0 /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /space /exclam /quotedbl /numbersign /dollar /percent /ampersand /quoteright /parenleft /parenright /asterisk /plus /comma /hyphen /period /slash /zero /one /two /three /four /five /six /seven /eight /nine /colon /semicolon /less /equal /greater /question /at /A /B /C /D /E /F /G /H /I /J /K /L /M /N /O /P /Q /R /S /T /U /V /W /X /Y /Z /bracketleft /backslash /bracketright /asciicircum /underscore /quoteleft /a /b /c /d /e /f /g /h /i /j /k /l /m /n /o /p /q /r /s /t /u /v /w /x /y /z /braceleft /bar /braceright /asciitilde /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /.notdef /dotlessi /grave /acute /circumflex /tilde /macron /breve /dotaccent /dieresis /.notdef /ring /cedilla /.notdef /hungarumlaut /ogonek /caron /space /exclamdown /cent /sterling /currency /yen /brokenbar /section /dieresis /copyright /ordfeminine /guillemotleft /logicalnot /hyphen /registered /macron /degree /plusminus /twosuperior /threesuperior /acute /mu /paragraph /periodcentered /cedilla /onesuperior /ordmasculine /guillemotright /onequarter /onehalf /threequarters /questiondown /Agrave /Aacute /Acircumflex /Atilde /Adieresis /Aring /AE /Ccedilla /Egrave /Eacute /Ecircumflex /Edieresis /Igrave /Iacute /Icircumflex /Idieresis /Eth /Ntilde /Ograve /Oacute /Ocircumflex /Otilde /Odieresis /multiply /Oslash /Ugrave /Uacute /Ucircumflex /Udieresis /Yacute /Thorn /germandbls /agrave /aacute /acircumflex /atilde /adieresis /aring /ae /ccedilla /egrave /eacute /ecircumflex /edieresis /igrave /iacute /icircumflex /idieresis /eth /ntilde /ograve /oacute /ocircumflex /otilde /odieresis /divide /oslash /ugrave /uacute /ucircumflex /udieresis /yacute /thorn /ydieresis ] 4

5 STREAM OBJECTS Stream objects are referenced by entries of kids in the page object. The contents in a page of a PDF file must be contained between the statements STREAM and ENDSTREAM in a stream object. Each line in a stream object starts with the beginning T* ( and ends with the ending ) Tj. The following example is a stream object OBJ STREAM ENDSTREAM MACROS DEVELOPMENTS Since a PDF file created by PDF PostScript language is object-structured, it makes sense to program the macros in SAS in an object-oriented style. Each object generated by the macro is independent from other objects. It s easy to debug and modify the macro. When archiving SAS programs in PDF, the macro SAS2PDF generates objects of a PDF file and uses the PUT statements to produce the PDF file. STREAM SAS CODES CREATING A FONT OBJECT The following codes generate the font object that is displayed in the above section. A PDF file with this font object can have the courier font with regular, italic, bold, and bold italic styles. FONTS: IF _n_=1 THEN DO; ARRAY font {5} $80 temporary_( "" "/Type /Font" "/Subtype /Type1" "" "endobj" ); ARRAY fstyle{4} $80 temporary_( "Courier" "Courier-Oblique" "Courier-Bold " "Courier-BoldOblique" ); DO j=1 TO 4; string=compress(put(obj+1,8.))!!' 0 obj'; addobj=1; LINK output; DO i=1 TO 3; string=font{i}; LINK output; END; string='/name /F'!!compress(put(j,8.)); LINK output; string='/encoding '!!compress(put(obj+5-j,8.))!!' 0 R'; LINK output; string='/basefont /'!!fstyle{j}; LINK output; DO i=4 TO 5; string=font{i}; 5

6 LINK output; END; END; END; RETURN; In developing the macro SAS2PDF, we added some specific features that are useful for the conversion of SAS programs and are not available in the existing tools that have already been developed to convert text files into PDF files on the PC and UNIX platforms. Although these existing tools, known as third-party software, can convert any text files into PDF files, they are not coded in SAS and are not 100% suitable for our specific requirements of the conversion. In contrast, macro SAS2PDF is written in SAS and customized for the conversion of SAS programs. Using PDF PostScript language to produce PDF files, macro SAS2PDF is developed for easy usage since it does not require any third-party software (like Adobe Acrobat ) for support. Also, it can be used in any SAS version because it does not use SAS ODS, and can be applied in any operating system where SAS can be installed and used. A PDF file produced by macro SAS2PDF is a text file. The macro PDF2SAS reads in the PDF file as a text file and saves it as an initial SAS data. It then determines the page object, selects text strings of the SAS programs in stream objects, and saves them as a SAS data. Finally, the SAS data is put out as SAS programs. ARCHIVING SAS PROGRAMS IN PDF The macro SAS2PDF has a number of useful features, which can be employed when archiving SAS programs to a PDF file. Like other text editors, the macro SAS2PDF has the ability to specify the font style and size, margin widths, and page orientation of the PDF file. The macro also allows users to add programs names and/or page numbers at the top and/or bottom of pages in the PDF file. There is also an option for a user specified watermark. In addition, macro SAS2PDF provides the user with the option to convert all or selected SAS programs in a directory to a PDF file in the same or another directory. One additional note, PDF files have a line-size restriction which is not present in SAS programs. When writing a SAS program, users are allowed to write a statement as long as possible, limited only by the capabilities of the text editor. When converting a SAS program to a PDF file, the macro SAS2PDF will identify any statements that are too long to fit in one line in a page of the PDF file. The macro wraps the remaining characters in the statement to the following lines in the page of the PDF file. This line wrap in then reversed if/when the program is restored back to SAS. The following two examples demonstrate more specifically how macro SAS2PDF can be used to archive SAS programs in PDF. EXAMPLE 1 The user is converting two SAS programs, DEMO.SAS and AE.SAS, to a PDF file named as DEMO_AE.PDF. Prior to calling the macro SAS2PDF, the user has defined a FILENAME associated with the directory, where the SAS programs are currently stored and the PDF will be created (C:\SAS2PDF\SASPROGRAMS). The user has also specified that the PDF file will have the font Times New Roman with the font size 8 and the font style Bold, the portrait page orientation with all margins 0.7 inch and the watermark Project. Program names and page numbers will be displayed at the top and bottom of each page. FILENAME SASDIRFN 'C:\SAS2PDF\SASPROGRAMS'; %SAS2PDF(Dir=SASDIRFN, MemType=SAS, Member=DEMO AE, PdfDir=SASDIRFN, PdfFile=DEMO_AE, Font=TimesNewRoman, FntStyle=B, FntSize=8, 6

7 PgHeader=Y, PgFooter=Y, WMargin=0.7, HMargin=0.7, WMark=Project, WmMargin=2, PortLand=L); EXAMPLE 2 In this example, the user would like to convert all SAS programs in the directory C:\SAS2PDF\SASPROGRAMS to a PDF file named as PROGRAMS.PDF in a different directory, C:\SAS2PDF\PDFFILES. The user has defined one FILENAME associated with the directory where SAS programs are stored and another FILENAME where the PDF file will be saved. The user has also specified that the PDF file will have the font COURIER with the font size 10 and the regular font style, the landscape page orientation with all margins 1 inch, and the watermark Centocor. A partial list of the bookmarks and one page of the converted PDF file in Acrobat Reader are shown at figure 1 in the Appendix. FILENAME SASDIRFN "C:\SAS2PDF\SASPROGRAMS"; FILENAME PDFDIRFN "C:\SAS2PDF\PDFFILES"; %SAS2PDF(Dir=SASDIRFN, MemType=SAS, Member=_ALL_, PdfDir=PDFDIRFN, PdfFile=PROGRAMS, Font=COURIER, FntStyle=R, FntSize=10, PgHeader=Y, PgFooter=Y, WMargin=1, HMargin=1, WMark=Centocor, WmMargin=2, PortLand=L); RETRIEVING SAS PROGRAMS FROM PDF FILES The PDF file created by the macro SAS2PDF can contain a single SAS program or multiple SAS programs. The macro PDF2SAS reads the bookmarks in the PDF file and separates the designated SAS programs into individual SAS files, each with the appropriate program name and contents. Each retrieved SAS program has the exact same contents and layout as it had prior to the archival process. A PDF file created by macro SAS2PDF may have page titles (i.e., programs names, page numbers) or a watermark. These additional texts in the PDF file are treated as the same as the contents of SAS programs when macro PDF2SAS retrieves them. In order to remove this additional text, the user can specify, when calling the macro, whether the PDF file has page titles, page numbers, or watermark. The macro will remove them during retrieval, if the PDF file has them. It s also possible that one long line in a SAS program may be wrapped into multiple lines of a page in the PDF file by macro SAS2PDF. The macro PDF2SAS is able to detect the wrappings in the PDF file automatically and put them back to one line in the retrieved SAS program. The unwrapped line in the retrieved SAS program has the exact same layout as the corresponding line in the SAS program before conversion. The following two examples demonstrate more specifically how macro PDF2SAS works to retrieve SAS programs from a PDF file. 7

8 EXAMPLE 3 A user wants to retrieve one SAS program, DEMO.SAS, from the PDF file, PROGRAMS.PDF, in the directory C:\PDF2SAS\PDFFILES and save it in the same directory. Before calling the macro, the user has defined the FILENAME associated with the directory. The user has also identified that the PDF file has page titles, page numbers and a watermark, all of which must be stripped from the programs in order to restore them to their original format. FILENAME PDFDIRFN "C:\PDF2SAS\PDFFILES"; %PDF2SAS(Dir=PDFDIRFN, PdfFile=PROGRAMS, PdfType=PDF, FileDir=PDFDIRFN, Files=DEMO, FileType=SAS, PgHeader=Y, PgFooter=Y, WMark=Y); EXAMPLE 4 In this example, the user wants to retrieve all SAS programs from a PDF file, PROGRAMS.PDF, in the directory C:\PDF2SAS\PDFFILES and save them in another directory C:\PDF2SAS\SASPROGRAMS. The user has defined two FILENAMEs associated with the two directories, the directory where a PDF file is stored and the directory where SAS programs will be saved. The user has identified that the PDF file has page titles, page numbers and watermark, all of which must be stripped from the programs in order to restore them to their original format. The PDF file PROGRAMS.PDF and multiple SAS programs retrieved from PROGRAMS.PDF are displayed in two Window Explorer screenshots, shown at figure 2 in the appendix. FILENAME PDFDIRFN "C:\PDF2SAS\PDFFILES"; FILENAME SASDIRFN "C:\PDF2SAS\SASPROGRAMS"; %PDF2SAS(DIR=PDFDIRFN, PdfFile=PROGRAMS, PdfType=PDF, FileDir=SASDIRFN, Files=_All_, FileType=SAS, PgHeader=Y, PgFooter=Y, WMark=Y); The macro also gives users another opportunity to execute SAS programs in a PDF file directly instead of retrieving them to a physical place. For example, the PDF file PROGRAMS.PDF contains one SAS program DEMO.SAS. If the user wants to execute DEMO.SAS in SAS without retrieving, he/she can modify the calling program in example 3 by assigning the parameter FILEDIR with BLANK. This will submit the modified calling program in SAS. VALIDATION As we mentioned above, we need make sure that the PDF file is archived appropriately. The best way of validation is that users retrieve SAS programs from the PDF file and then compare them with the original SAS programs. The retrieved SAS programs should be the same as the original SAS programs. If they are different, users should look at the original SAS programs and check why they are different. The original SAS programs may have special characters or some SAS programs may be missed in the PDF file. The user might change the layout of the original SAS programs a little bit as needed. The discrepancy should disappear after the appropriate modifications of the original SAS programs. If the retrieved SAS programs are the same as the original SAS programs, the result of executing the macro VAL2PDF displays a statement All files match in SAS log. If the number of the retrieved SAS programs is less 8

9 than the number of the original SAS programs, or SAS programs have discrepancies between before archiving and after retrieving, the SAS log will list these programs names. EXAMPLE 5 This example shows how to execute the macro VALOFPDF. The original SAS programs are stored in C:\SAS2PDF\SASPROGRAMS and the retrieved SAS programs are stored in C:\PDF2SAS\SASPROGRAMS. FILENAME SASPDFFN "C:\SAS2PDF\SASPROGRAMS"; FILENAME PDFSASFN "C:\PDF2SAS\SASPROGRAMS"; %VALOFPDF(SASDir=SASPDFFN, Member=ALL, MemType=SAS, PDFDir=PDFSASFN); PROCEDURE OF ARCHIEVING SAS PROGRAMS After we discussed the macros, the features and the usage of the macros, we are ready for the procedure of archiving programs in PDF. The following steps illustrates the steps of the procedure: 1) Select and clean SAS programs, create a temporary folder, and copy the selected and cleaned SAS programs to this folder; 2) Execute the macro SAS2PDF and archive SAS programs from the above folder and save a PDF file in the folder wherever users would like to save it; 3) Create another temporary folder for the retrieved SAS programs, execute the macro PDF2SAS and save the retrieved SAS programs in that folder; 4) Execute the macro VAL2PDF to check whether there are any discrepancies between the original SAS programs and the retrieved SAS programs. If the discrepancies happen, check the original SAS programs, and find reasons. Users may modify the layouts of programs as needed and follow the above steps 1 to 3 again until the discrepancies disappear; 5) Delete the original and retrieved SAS programs and the temporary folders. CONCLUSION If SAS users would like to archive SAS programs in PDF and retrieve SAS programs from the PDF file that contains SAS programs, the macros SAS2PDF and PDF2SAS are a good choice. They are written in SAS with PDF PostScript language and are easy for updating or modification. The macros achieve most features that other similar tools have and have specific functions that other tools don t have. The macros are simple, easy to use for any level SAS users, and work well on any platforms wherever SAS works. ACKNOWLEDGEMENTS The authors would like to express their appreciation to the following people for reviewing the paper, comments and the support of publication of the paper: Beverly Hayes, Centocor Research & Development, Inc. CONTACT INFORMATION Your comments and questions are valued and encouraged. You may contact the authors by mails or s at the following addresses: Eric Zhang, ezhang5@cntus.jnj.com Leah Bednarek, lbednare@cntus.jnj.com Daniel Hofstaedter, dhofstae@cntus.jnj.com Centocor Research & Development, Inc., C Great Valley Parkway 9

10 Malvern, PA SAS and all other SAS Institute Inc. product or service names are registered trademarks or trademarks of SAS Institute Inc. in the USA and other countries indicates USA registration. Other brand and product names are trademarks of their respective companies. 10

11 APPENDIX Figure 1: A PDF file created by SAS2PDF PROGRAMS.PDF

12 Figure 2: A converted PDF file created by SAS2PDF PROGRAMS.PDF at window explorer in the left side and SAS programs retrieved form PROGRAMS.PDF by PDF2SAS at window explorer in the right side