How to Add Compression to a VFP Program Without ActiveX, Without $

*******************************************************
* zLib.prg
*  Author: William GC Steinford
*    Date: June 20, 2002
* Purpose: Easy to use Compress/Uncompress utilities
*            for VFP
*******************************************************
PROCEDURE zLib
PARAMETER cFunc, cStr
  DO CASE
    CASE upper(cFunc)='COMPRESS'
      RETURN CompressIt(cStr)
    CASE upper(cFunc)='UNCOMPRESS'
      RETURN UnCompressIt(cStr)
  ENDCASE
RETURN '
* Functions:
*!*	int compress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen); 
*!*	int uncompress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen); 

Function CompressIt( InFile )
DECLARE INTEGER compress IN zlib.dll AS zlibCompress ;
  STRING @ dest, INTEGER @ destLen, ;
  STRING src, INTEGER srcLen
* Compresses the source buffer into the destination buffer. 
*   sourceLen is the byte length of the source buffer. Upon entry, 
*   destLen is the total size of the destination buffer, which must 
*   be at least 0.1% larger than sourceLen plus 12 bytes. Upon exit, 
*   destLen is the actual size of the compressed buffer.
LOCAL lnSize, lcBuff, lnFinalSize
lnSize = len(InFile)
*123,456,789,012,345  15 chars is enough for 100 Terabytes.
*100,000,000,000,000
lcBuff      = space( len(InFile)*1.2 )
lnFinalSize = len(lcBuff)
Res = zlibCompress( @lcBuff, @lnFinalSize, InFile, lnSize )
If Res=0 && Success
  RETURN PadL( alltrim(str(lnSize)), 15, '0' ) + Left( lcBuff, lnFinalSize ) 
endif
RETURN '

****************************************************************************
* Proc UnCompressIt
*  The first 15 chars MUST be the (decimal) size of the uncompressed file
FUNCTION UnCompressIt( zLibFile )
DECLARE INTEGER uncompress IN zlib.dll AS zlibUnCompress ;
  STRING @ dest, INTEGER @ destLen, ;
  STRING src, INTEGER srcLen
* Decompresses the source buffer into the destination buffer. 
*   sourceLen is the byte length of the source buffer. Upon entry, 
*   destLen is the total size of the destination buffer, which must 
*   be large enough to hold the entire uncompressed data. 
* (The size of the uncompressed data must have been saved previously 
*  by the compressor and transmitted to the decompressor by some mechanism 
*  outside the scope of this compression library.) 
*  Upon exit, destLen is the actual size of the compressed buffer. 
* This function can be used to decompress a whole file at once if the input file is mmap'ed. 
*
LOCAL lnSize, lcBuff, lnFinalSize
lnSize = len(zLibFile)
*123,456,789,012,345  15 chars is enough for 100 Terabytes.
*100,000,000,000,000
lnFinalSize = Val( Left( zLibFile, 15 ) )
lcBuff      = space( lnFinalSize )
zLibFile    = SubStr( zLibFile, 16 )
Res = zlibUnCompress( @lcBuff, @lnFinalSize, zLibFile, lnSize )
If Res=0 && Success
  RETURN lcBuff
endif
RETURN '
********************************************************

  SET PROCEDURE TO zLib ADDITIVE
  x = CompressIt( FileToStr("testfile.txt") )
  y = UnCompressIt( x )
  StrToFile( y, "testfile.txt.out" )
  RELEASE PROCEDURE zLib

** OR **

  x = zLib("CompressIt", FileToStr("testfile.txt") )
  y = zLib("UnCompressIt", x )
  StrToFile( y, "testfile.txt.out" )

  SET PROC TO (srcDrv+"\source\las\zLib") ADDITIVE
  
  CREATE TABLE plg_Inst.dbf ;
    ( FileName   C(30), ;
      FileData   M,     ;
      Register   L,     ;
      Compressed L,     ;
      OrigSize   N(15)   )
  Select Plg_Inst
  fCnt = aDir( fArr, "*.HTM" )
  if fCnt > 0
    for fNum = 1 to fCnt
      append blank
      REPLACE FileName with fArr[fNum,1], ;
              FileData with CompressIt( FileToStr(fArr[fNum,1]) ), ;
              Compressed with .T.
    endfor
  endif

  if file('PLG_INST.DBF') and file('PLG_INST.FPT')
    * Copy DBF/FPT out because VFP has "issues" with
    *   accessing "included" FPT files.
    aa=FileToStr('PLG_INST.DBF')
    bb=FileToStr('PLG_INST.FPT')
    StrToFile(aa,'tmp_Inst.dbf')
    StrToFile(bb,'tmp_Inst.fpt')
    SELECT 0
    USE TMP_INST.DBF ALIAS plg_Inst
    * Dump out all internal files!
    SCAN
      If not empty(Plg_inst.FileName) ;
         and not empty(Plg_inst.FileData)
        if Plg_Inst.Compressed
          lcCompFile   = Plg_Inst.FileData
          lcUnCompFile = zLib("UnCompressIt", lcCompFile )
          if not empty(lcUnCompFile)
            =StrToFile( lcUnCompFile, alltrim(Plg_Inst.FileName) )
          else
            =MessageBox( 'Could not uncompress file "'+Plg_Inst.FileName+'".', mbxOk)
          endif
        else
          =StrToFile( Plg_Inst.FileData, alltrim(Plg_Inst.FileName) )
        endif
      endif
    ENDSCAN
    USE
    IF FILE('TMP_INST.DBF')
      DELETE FILE TMP_INST.DBF
    ENDIF
    IF FILE('TMP_INST.FPT')
      DELETE FILE TMP_INST.FPT
    ENDIF
  else
    =MessageBox('Error Installing additional files!',mbxOk,')
  endif