How to Find the Size of an .FPT File with Different Blocksizes

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1. Open a program file called LowLevel.prg and add this code:

      FUNCTION BLOCKTEST
      PARAMETER lnTempsize
      CLEAR
      IF lnTempsize>0
        IF lnTempsize<=32
          lnTempsize=lnTempsize*512
        ENDIF
        lnTempblk=0
        lcFilename=LEFT(DBF(),LEN(DBF())-4)
        lnBlksize=VAL(SYS(2012))
        USE
        lnHandle=FOPEN(lcFilename+".FPT")
        IF lnHandle>0
           lnFilesize=FSEEK(lnHandle,0,2)
           =FSEEK(lnHandle,0)
           lcByte=FREAD(lnHandle,8)
           lnBlknum=ASC(SUBSTR(lcByte,4,1))+(ASC(SUBSTR(lcByte,3,1))*256)+;
              (ASC(SUBSTR(lcByte,2,1))*256*256)+;
              (ASC(SUBSTR(lcByte,1,1))*256*256*256)
           ?  "Current Memo Stats"
           ?  "    Blocksize    "+ALLTRIM(STR(lnBlksize))
           ?  "    # of blocks  "+ALLTRIM(STR(lnBlknum))
           ?  "    Filesize     "+ALLTRIM(STR(lnFilesize))+" Bytes"
           lnBlkend=0
           lni=1
           DO WHILE lnBlkend<512
              lnBlkend=lni*lnBlksize
              lni=lni+1
           ENDDO
           =FSEEK(lnHandle,lnBlkend+4)
           lnRec=0
           FOR lni=lni TO lnBlknum
              lcByte=FREAD(lnHandle,4)
              =FSEEK(lnHandle,lnBlksize-4,1)
              IF (lnBlksize*lni)>lnBlkend
                 lnx=ASC(SUBSTR(lcByte,4,1))+:
                    (ASC(SUBSTR(lcByte,3,1))*256)+;
                    (ASC(SUBSTR(lcByte,2,1))*256*256)+;
                    (ASC(SUBSTR(lcByte,1,1))*256*256*256)+8
                 lnRec=lnRec+1
                 lnk=INT((lnx-1)/lnBlksize)
                 lni=lni+lnk
                 lnTempblk=lnTempblk+INT(lnx/lnTempsize)+;
                    IIF(MOD(lnx,lnTempsize)=0,0,1)
                 =FSEEK(lnHandle,(lnBlksize*lnk),1)
              ENDIF
           ENDFOR
           =FCLOSE(lnHandle)
           lnTempblk=lnTempblk+INT(512/lnTempsize)+;
              IIF(MOD(512,lnTempsize)=0,0,1)
           lnTempfile=lnTempsize*lnTempblk
           ?
           ?  "Requested Memo Stats"
           ?  "    Blocksize    "+ALLTRIM(STR(lnTempsize))
           ?  "    # of blocks  "+ALLTRIM(STR(lnTempblk))
           ?  "    Filesize     "+ALLTRIM(STR(lnTempfile))+" Bytes"
           ?
           ? "Savings: "+ALLTRIM(STR(lnFilesize-lnTempfile))+" Bytes"
           USE &lcFilename
           IF lnRec>RECCOUNT()
             ?
             ? ALLTRIM(str(lnrec-reccount()))+;
                " disconneted records in memo file."
             ? "Please PACK MEMO and run this command again"
           ENDIF
           RETURN lnTempfile
        ENDIF
      ENDIF
   						

2. Save and close LowLevel.prg.
3. Test the function by opening a table with a memo field. For this example, the table is Restaurs.dbf. A blocksize of 64 will be tested. In the Command window, type:

      SET PROCEDURE TO LOWLEVEL.PRG
      USE C:\FPW26\SAMPLE\ORGANIZE\DBFS\RESTAURS
      =BLOCKTEST(64)
   						

   Note that if the current blocksize is 64, there will be no savings in creating a new file with the same blocksize.
4. Test it again using the following different block sizes:

      =BLOCKTEST(32)
      =BLOCKTEST(35)
      =BLOCKTEST(40)
   						

5. To change the blocksize of Restaurs.dbf TO 40, use these commands:

      SET BLOCKSIZE TO 40
      COPY TO TEMP
      USE
   
      ERASE RESTAURS.DBF
      ERASE RESTAURS.FPT
   
      RENAME TEMP.DBF TO RESTAURS.DBF
      RENAME TEMP.FPT TO RESTAURS.FPT