How to read FoxPro Memo with PHP?

Question

I have to convert .DBF and .FPT files from Visual FoxPro to MySQL. Right now my script works for .DBF files, it opens and reads them with dbase_open() and dbase_get_record_with_names() and then executes the MySQL INSERT commands.

However, some fields of these .DBF files are of type MEMO and therefore stored in a separate files ending in .FPT. How do I read this file?

I have found the specifications of this filetype in MSDN, but I don't know how I can read this file byte-wise with PHP (also, I would really prefer a simplier solution).

Any ideas?

Answer 1

Alright, I have carefully studied the MSDN specifications of DBF and FPT file structures and the outcome is a beautiful PHP class which can open a DBF and (optional) an FPT memo file at the same time. This class will give you record after record and thereby fetch any memos from the memo file - if opened.

class Prodigy_DBF {
    private $Filename, $DB_Type, $DB_Update, $DB_Records, $DB_FirstData, $DB_RecordLength, $DB_Flags, $DB_CodePageMark, $DB_Fields, $FileHandle, $FileOpened;
    private $Memo_Handle, $Memo_Opened, $Memo_BlockSize;

    private function Initialize() {

        if($this->FileOpened) {
            fclose($this->FileHandle);
        }

        if($this->Memo_Opened) {
            fclose($this->Memo_Handle);
        }

        $this->FileOpened = false;
        $this->FileHandle = NULL;
        $this->Filename = NULL;
        $this->DB_Type = NULL;
        $this->DB_Update = NULL;
        $this->DB_Records = NULL;
        $this->DB_FirstData = NULL;
        $this->DB_RecordLength = NULL;
        $this->DB_CodePageMark = NULL;
        $this->DB_Flags = NULL;
        $this->DB_Fields = array();

        $this->Memo_Handle = NULL;
        $this->Memo_Opened = false;
        $this->Memo_BlockSize = NULL;
    }

    public function __construct($Filename, $MemoFilename = NULL) {
        $this->Prodigy_DBF($Filename, $MemoFilename);
    }

    public function Prodigy_DBF($Filename, $MemoFilename = NULL) {
        $this->Initialize();
        $this->OpenDatabase($Filename, $MemoFilename);
    }

    public function OpenDatabase($Filename, $MemoFilename = NULL) {
        $Return = false;
        $this->Initialize();

        $this->FileHandle = fopen($Filename, "r");
        if($this->FileHandle) {
            // DB Open, reading headers
            $this->DB_Type = dechex(ord(fread($this->FileHandle, 1)));
            $LUPD = fread($this->FileHandle, 3);
            $this->DB_Update = ord($LUPD[0])."/".ord($LUPD[1])."/".ord($LUPD[2]);
            $Rec = unpack("V", fread($this->FileHandle, 4));
            $this->DB_Records = $Rec[1];
            $Pos = fread($this->FileHandle, 2);
            $this->DB_FirstData = (ord($Pos[0]) + ord($Pos[1]) * 256);
            $Len = fread($this->FileHandle, 2);
            $this->DB_RecordLength = (ord($Len[0]) + ord($Len[1]) * 256);
            fseek($this->FileHandle, 28); // Ignoring "reserved" bytes, jumping to table flags
            $this->DB_Flags = dechex(ord(fread($this->FileHandle, 1)));
            $this->DB_CodePageMark = ord(fread($this->FileHandle, 1));
            fseek($this->FileHandle, 2, SEEK_CUR);    // Ignoring next 2 "reserved" bytes

            // Now reading field captions and attributes
            while(!feof($this->FileHandle)) {

                // Checking for end of header
                if(ord(fread($this->FileHandle, 1)) == 13) {
                    break;  // End of header!
                } else {
                    // Go back
                    fseek($this->FileHandle, -1, SEEK_CUR);
                }

                $Field["Name"] = trim(fread($this->FileHandle, 11));
                $Field["Type"] = fread($this->FileHandle, 1);
                fseek($this->FileHandle, 4, SEEK_CUR);  // Skipping attribute "displacement"
                $Field["Size"] = ord(fread($this->FileHandle, 1));
                fseek($this->FileHandle, 15, SEEK_CUR); // Skipping any remaining attributes
                $this->DB_Fields[] = $Field;
            }

            // Setting file pointer to the first record
            fseek($this->FileHandle, $this->DB_FirstData);

            $this->FileOpened = true;

            // Open memo file, if exists
            if(!empty($MemoFilename) and file_exists($MemoFilename) and preg_match("%^(.+).fpt$%i", $MemoFilename)) {
                $this->Memo_Handle = fopen($MemoFilename, "r");
                if($this->Memo_Handle) {
                    $this->Memo_Opened = true;

                    // Getting block size
                    fseek($this->Memo_Handle, 6);
                    $Data = unpack("n", fread($this->Memo_Handle, 2));
                    $this->Memo_BlockSize = $Data[1];
                }
            }
        }

        return $Return;
    }

    public function GetNextRecord($FieldCaptions = false) {
        $Return = NULL;
        $Record = array();

        if(!$this->FileOpened) {
            $Return = false;
        } elseif(feof($this->FileHandle)) {
            $Return = NULL;
        } else {
            // File open and not EOF
            fseek($this->FileHandle, 1, SEEK_CUR);  // Ignoring DELETE flag
            foreach($this->DB_Fields as $Field) {
                $RawData = fread($this->FileHandle, $Field["Size"]);
                // Checking for memo reference
                if($Field["Type"] == "M" and $Field["Size"] == 4 and !empty($RawData)) {
                    // Binary Memo reference
                    $Memo_BO = unpack("V", $RawData);
                    if($this->Memo_Opened and $Memo_BO != 0) {
                        fseek($this->Memo_Handle, $Memo_BO[1] * $this->Memo_BlockSize);
                        $Type = unpack("N", fread($this->Memo_Handle, 4));
                        if($Type[1] == "1") {
                            $Len = unpack("N", fread($this->Memo_Handle, 4));
                            $Value = trim(fread($this->Memo_Handle, $Len[1]));
                        } else {
                            // Pictures will not be shown
                            $Value = "{BINARY_PICTURE}";
                        }
                    } else {
                        $Value = "{NO_MEMO_FILE_OPEN}";
                    }
                } else {
                    $Value = trim($RawData);
                }

                if($FieldCaptions) {
                    $Record[$Field["Name"]] = $Value;
                } else {
                    $Record[] = $Value;
                }
            }

            $Return = $Record;
        }

        return $Return;
    }

    function __destruct() {
        // Cleanly close any open files before destruction
        $this->Initialize();
    }
}

The class can be used like this:

    $Test = new Prodigy_DBF("customer.DBF", "customer.FPT");
    while(($Record = $Test->GetNextRecord(true)) and !empty($Record)) {
        print_r($Record);
    }

It might not be an almighty perfect class, but it works for me. Feel free to use this code, but note that the class is VERY tolerant - it doesn't care if fread() and fseek() return true or anything else - so you might want to improve it a bit before using.

Also note that there are many private variables like number of records, recordsize etc. which are not used at the moment.