Convert ORA_FFI to WEBUTIL_C_API to print locally

Question

I am trying to figure out how to convert this package to WEBUTIL_C_API to be able to print to a users local printer (EPSON slip printer)... ANY help would be appreciated...
PACKAGE EPSON_SLIP_PRINTER_INTERFACE IS
* This package provides functions to interact with the EPSON
* TM-U295 slip printers.
* The OPEN_PRINTER function must be called to obtain a printer ID.
* This printer ID can then be used when calling other functions
* that require a printer to be specified.
* NOTE that the printer ID is only valid within the same thread
* that called the OPEN_PRINTER function.
* Brendan Rickey 2004-JAN-09
-- AVAILABLE PRINTERS
CHEQUE_PRINTER     VARCHAR2(50) := 'Generic / Text Only droite';
INVOICE_PRINTER     VARCHAR2(50) := 'Generic / Text Only left';
-- ERROR CODES
-- Some of the provided functions return a NUMBER value that may hold
-- an error code (negative number).
-- These are the possible error codes:
SUCCESS                    NUMBER := 0;     --no error
ERR_TYPE               NUMBER := -10;     --parameter type error
ERR_OPENED               NUMBER := -20; --printer already opened
ERR_NO_PRINTER     NUMBER := -30;     --the printer driver does not exist
ERR_NO_TARGET          NUMBER := -40;     --no printer found (could of off, faulty, unsupported)
ERR_NO_MEMORY          NUMBER := -50;     --insufficient memory
ERR_HANDLE               NUMBER := -60;     --invalid printer ID
ERR_TIMEOUT               NUMBER := -70;     --time out error
ERR_ACCESS               NUMBER := -80;     --cannot read/write to printer (printing in progress)
ERR_PARAM               NUMBER := -90;     --parameter error
ERR_OFFLINE               NUMBER := -110;     --printer was opened in offline state.  Status must be changed to online.
ERR_NOT_EPSON          NUMBER := -120;     --printer is not an EPSON printer
* INITIALIZE
* Initializes the interface between Forms and the EPSON library (call before any other function in the package).
* Returns:
* TRUE if the library is registered successfully,
* FALSE otherwise (library not found etc...)
function INITIALIZE return BOOLEAN;
* OPEN_PRINTER
* Obtains a handle on the specified EPSON slip printer (either CHEQUE_PRINTER or INVOICE_PRINTER).
* Returns:
*           a printer ID for the specified printer (greater than 0)
*           an error code on failure (less than 0):
* ERR_TYPE, ERR_OPENED, ERR_NO_PRINTER, ERR_NO_TARGET, ERR_NO_MEMORY, ERR_PARAM
function OPEN_PRINTER (p_printer_name IN VARCHAR2) return NUMBER;
* CLOSE_PRINTER
* Releases the handle on the specified printer.
* Returns:
*           0 on success
*           ERR_HANDLE on failure
function CLOSE_PRINTER (p_printer_id IN NUMBER) return NUMBER;
* IS_PAPER_OUT
* Tests if there is no paper in the printer.
* Returns:
*           1 if there is no paper in the printer, 0 if paper is in the printer
*           ERR_HANDLE or ERR_PARAM on failure.
function IS_PAPER_OUT (p_printer_id IN NUMBER) return NUMBER;
* PRINT_TEXT
* Prints the specified text to the specified printer.
* Returns:
*           0 on success
*           ERR_HANDLE, ERR_ACCESS, ERR_OFFLINE, ERR_NOT_EPSON, or ERR_PARAM on failure.
function PRINT_TEXT (p_printer_id IN NUMBER, p_text IN VARCHAR2) return NUMBER;
* RELEASE_PAPER
* Performs the Release function on the specified printer.
* Returns:
*           0 on success
*           ERR_HANDLE, ERR_ACCESS, ERR_OFFLINE, ERR_NOT_EPSON, or ERR_PARAM on failure.
function RELEASE_PAPER (p_printer_id IN NUMBER) return NUMBER;
/* PRIVATE FUNCTIONS
function BiOpenMonPrinter(arg0 in PLS_INTEGER,
arg1 in out VARCHAR2)
return PLS_INTEGER;
function BiCloseMonPrinter(arg0 in PLS_INTEGER)
return PLS_INTEGER;
function BiGetStatus(arg0 in PLS_INTEGER,
arg1 in out PLS_INTEGER)
return PLS_INTEGER;
function BiDirectIO(arg0 in PLS_INTEGER,
arg1 in PLS_INTEGER,
arg2 in out VARCHAR2,
arg3 in out PLS_INTEGER,
arg4 in out VARCHAR2,
arg5 in PLS_INTEGER,
arg6 in PLS_INTEGER)
return PLS_INTEGER;
function BiDirectIOEx(arg0 in PLS_INTEGER,
arg1 in PLS_INTEGER,
arg2 in out VARCHAR2,
arg3 in out PLS_INTEGER,
arg4 in out VARCHAR2,
arg5 in PLS_INTEGER,
arg6 in PLS_INTEGER,
arg7 in PLS_INTEGER)
return PLS_INTEGER;
END;
PACKAGE BODY EPSON_SLIP_PRINTER_INTERFACE IS
v_msg_b VARCHAR2(20);
v_EPSON_LIBRARY_OK BOOLEAN:= FALSE;
--ORA_FFI function handles and library handle
lh_EpsStmApi ora_ffi.libHandleType;                    --DLL library handle
fh_BiOpenMonPrinter ora_ffi.funcHandleType;          --DLL function handle
fh_BiCloseMonPrinter ora_ffi.funcHandleType;     --DLL function handle
fh_BiGetStatus ora_ffi.funcHandleType;               --DLL function handle
fh_BiDirectIO ora_ffi.funcHandleType;               --DLL function handle
fh_BiDirectIOEx ora_ffi.funcHandleType;               --DLL function handle
--constant
ASB_SLIP_BOF     PLS_INTEGER := 4*power(16,5);     --BOF printer status flag 0x00400000
c_release_code      CHAR(2) := CHR(27)||CHR(113);     --ESC+q, to release the paper
-------PRIVATE FUNCTIONS--------
* Brendan Rickey 2004-JAN-09
* The following are functions that are required to interface with the
* EPSON StatusAPI DLL (C library) though ORA_FFI.
* The following describes the DLL functions that are made available
* through this ORA_FFI implementation:
Function Purpose
BiOpenMonPrinter Get a handle on a printer.
Parameters
p_Type --int: 1 if p_Name is a port, 2 if a printer name.
,p_Name --varchar2: the port of printer name to open.
Return printer identifier number (>0) on success, < 0 on failure.
BiCloseMonPrinter Close the monitor on the printer.
Parameters
p_Handle --int: The numerical printer handle returned from BiOpenMonPrinter.
Return 0 on success, < 0 on failure.
BiGetStatus Returns the status of the printer.
Parameters     
p_Handle --int: The numerical printer handle returned from BiOpenMonPrinter.
,p_Status OUT --long: The status of the printer (use AND bitwise operator to test for statuses).
Return 0 on success, < 0 on failure.
BiDirectIO Sends data to and Reads data from the printer. Use BiDirectIOEx if more that 255 chars are to be written/read.
Parameters
p_Handle --int: The numerical printer handle returned from BiOpenMonPrinter.
,p_WriteLen --short: The length of the command/data being sent to the printer (max 255).
,p_WriteCmd --varchar2: The command/data to send to the printer.
,p_ReadLen --short: The length of the data to be read from the printer (max 255)
(Use 0 if no data is to be read).
,p_ReadBuff OUT --varchar2: The buffer where the the data read from the printer is stored.
,p_Timeout --long: write/read time out in msecs.
,p_NullTerminate --short: 0 => reading of data from printer is performed until time out or length of p_ReadLen is reached.
1 => reading is finished at thepoint when a NULL is received from the printer. ReadLen must have a value.
Return 0 on success, < 0 on failure.
BiDirectIOEx Sends data to and Reads data from the printer (handles larger quantities of write/read data).
Parameters
p_Handle --int: The numerical printer handle returned from BiOpenMonPrinter.
,p_WriteLen --long: The length of the command/data being sent to the printer.
,p_WriteCmd --varchar2: The command/data to send to the printer.
,p_ReadLen --long: The length of the data to be read from the printer (Use 0 if no data is to be read).
,p_ReadBuff OUT --varchar2: The buffer where the the data read from the printer is stored.
,p_Timeout --long: write/read time out in msecs.
,p_NullTerminate --short: 0 => reading of data from printer is performed until time out or length of p_ReadLen is reached.
1 => reading is finished at thepoint when a NULL is received from the printer. ReadLen must have a value.
,p_Option --short: 0 => prevents Automatic Status Back (ASB) during execution of this function (as does BiDirectIO).
1 => does not disable Automatic Status Back (ASB).
Return 0 on success, < 0 on failure.
function icd_BiOpenMonPrinter(funcHandle in ora_ffi.funcHandleType, arg0 in PLS_INTEGER,
arg1 in out VARCHAR2)
return PLS_INTEGER;
pragma interface(c, icd_BiOpenMonPrinter, 11265);
function BiOpenMonPrinter(arg0 in PLS_INTEGER,
arg1 in out VARCHAR2)
return PLS_INTEGER is
begin
return(icd_BiOpenMonPrinter(fh_BiOpenMonPrinter,
arg0,
arg1));
end;
function icd_BiCloseMonPrinter(funcHandle in ora_ffi.funcHandleType, arg0 in PLS_INTEGER)
return PLS_INTEGER;
pragma interface(c, icd_BiCloseMonPrinter, 11265);
function BiCloseMonPrinter(arg0 in PLS_INTEGER)
return PLS_INTEGER is
begin
return(icd_BiCloseMonPrinter(fh_BiCloseMonPrinter,
arg0));
end;
function icd_BiGetStatus(funcHandle in ora_ffi.funcHandleType, arg0 in PLS_INTEGER,
arg1 in out PLS_INTEGER)
return PLS_INTEGER;
pragma interface(c, icd_BiGetStatus, 11265);
function BiGetStatus(arg0 in PLS_INTEGER,
arg1 in out PLS_INTEGER)
return PLS_INTEGER is
begin
return(icd_BiGetStatus(fh_BiGetStatus,
arg0,
arg1));
end;
function icd_BiDirectIO(funcHandle in ora_ffi.funcHandleType, arg0 in PLS_INTEGER,
arg1 in PLS_INTEGER,
arg2 in out VARCHAR2,
arg3 in out PLS_INTEGER,
arg4 in out VARCHAR2,
arg5 in PLS_INTEGER,
arg6 in PLS_INTEGER)
return PLS_INTEGER;
pragma interface(c, icd_BiDirectIO, 11265);
function BiDirectIO(arg0 in PLS_INTEGER,
arg1 in PLS_INTEGER,
arg2 in out VARCHAR2,
arg3 in out PLS_INTEGER,
arg4 in out VARCHAR2,
arg5 in PLS_INTEGER,
arg6 in PLS_INTEGER)
return PLS_INTEGER is
begin
return(icd_BiDirectIO(fh_BiDirectIO,
arg0,
arg1,
arg2,
arg3,
arg4,
arg5,
arg6));
end;
function icd_BiDirectIOEx(funcHandle in ora_ffi.funcHandleType, arg0 in PLS_INTEGER,
arg1 in PLS_INTEGER,
arg2 in out VARCHAR2,
arg3 in out PLS_INTEGER,
arg4 in out VARCHAR2,
arg5 in PLS_INTEGER,
arg6 in PLS_INTEGER,
arg7 in PLS_INTEGER)
return PLS_INTEGER;
pragma interface(c, icd_BiDirectIOEx, 11265);
function BiDirectIOEx(arg0 in PLS_INTEGER,
arg1 in PLS_INTEGER,
arg2 in out VARCHAR2,
arg3 in out PLS_INTEGER,
arg4 in out VARCHAR2,
arg5 in PLS_INTEGER,
arg6 in PLS_INTEGER,
arg7 in PLS_INTEGER)
return PLS_INTEGER is
begin
return(icd_BiDirectIOEx(fh_BiDirectIOEx,
arg0,
arg1,
arg2,
arg3,
arg4,
arg5,
arg6,
arg7));
end;
--------PUBLIC FUNCTIONS--------
function INITIALIZE return BOOLEAN IS
BEGIN
--When this is the first package function called, code in the package's
--body is executed and sets v_EPSON_LIBRARY_OK.
RETURN v_EPSON_LIBRARY_OK;
END;
function OPEN_PRINTER (p_printer_name IN VARCHAR2) return NUMBER IS
     v_printer                    PLS_INTEGER;
     v_printer_name     VARCHAR2(50) := p_printer_name;
     v_name_type           PLS_INTEGER := 2; --use printer Name to specify printer     
BEGIN
     /* Open a monitor for the printer */
     v_printer := BiOpenMonPrinter(v_name_type,v_printer_name);
     RETURN v_printer;
END;
function CLOSE_PRINTER (p_printer_id IN NUMBER) return NUMBER IS
v_return PLS_INTEGER;
BEGIN
/* CLOSE the printer monitor */
     v_return := BiCloseMonPrinter(p_printer_id);
     RETURN v_return;
END;
function IS_PAPER_OUT (p_printer_id IN NUMBER) return NUMBER IS
     v_return          PLS_INTEGER;
     v_status          PLS_INTEGER := -123456;
BEGIN
     /* Test if paper is in the printer by first getting the status (a binary integer) */
     v_return := BiGetStatus(p_printer_id,v_status);
     IF v_return <> 0 THEN
          RETURN v_return;
     ELSE
     --Test for BOF status flag
     IF WIN_API_BITOP.BITWISE_AND(v_status,ASB_SLIP_BOF) = ASB_SLIP_BOF THEN
          RETURN 1; --paper out
     ELSE
          RETURN 0; --paper in
     END IF;
     END IF;
END;
function PRINT_TEXT (p_printer_id IN NUMBER, p_text IN VARCHAR2) return NUMBER IS
v_return          PLS_INTEGER;
v_text               VARCHAR2(2000) := p_text;
v_text_len          PLS_INTEGER;                    --number of characters to be printed
v_read_len      PLS_INTEGER := 0;               --number of characters to be read from the printer
v_read_buff      VARCHAR2(255) := NULL;          --not used: holds characters read from the printer
v_timeout      PLS_INTEGER := 1000;          --not used: amount of time to wait for response (msecs)
     v_nullTerm          PLS_INTEGER := 0;               --not used: 0 means read until reached v_read_len or v_timeout
     -- 1 means read until NULL received from printer
     v_option          PLS_INTEGER := 0;           --0 means do not answer other requests while printing
                                                            --1 means do not stop answering other requests while printing
BEGIN
     --Get the number of chars to be printed and then print.
     v_text_len := length(p_text);
     v_return := BiDirectIOEx(p_printer_id,
     v_text_len,
     v_text,
     v_read_len,
     v_read_buff,
     v_timeout,
     v_nullTerm,
     v_option);
     --Ignore timeout(-70) errors, otherwise return error
     IF v_return = -70 THEN
          v_return := 0;     
     END IF;
     RETURN v_return;
END;
function RELEASE_PAPER (p_printer_id IN NUMBER) return NUMBER IS
BEGIN
/* Release the paper by sending the release escape code to the printer */
     RETURN PRINT_TEXT(p_printer_id, c_release_code);
END;
-----END OF FUNCTION IMPLEMENTATIONS-----
BEGIN
* Load the EPSON printer driver's StatusAPI library.
* Create an ORA_FFI interface to the library by doing the following for each desired function:
*          1- Create a handle on the function,
*          2- Register the return value,
*          3- Register the arguments/parameters in the correct order.
lh_EpsStmApi := ora_ffi.load_library('', 'EpsStmApi.DLL');
IF Ora_Ffi.Is_Null_Ptr(lh_EpsStmApi) THEN
     AFC_MESSAGES('I','MAIN-0020','E',v_msg_b);
     v_EPSON_LIBRARY_OK := FALSE;
ELSE
fh_BiOpenMonPrinter := ora_ffi.register_function(lh_EpsStmApi, 'BiOpenMonPrinter', ora_ffi.c_std);
ora_ffi.register_return(fh_BiOpenMonPrinter, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiOpenMonPrinter, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiOpenMonPrinter, ora_ffi.c_char_ptr, ora_ffi.pls_varchar2);
fh_BiCloseMonPrinter := ora_ffi.register_function(lh_EpsStmApi, 'BiCloseMonPrinter', ora_ffi.c_std);
ora_ffi.register_return(fh_BiCloseMonPrinter, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiCloseMonPrinter, ora_ffi.c_int, ora_ffi.pls_pls_integer);
fh_BiGetStatus := ora_ffi.register_function(lh_EpsStmApi, 'BiGetStatus', ora_ffi.c_std);
ora_ffi.register_return(fh_BiGetStatus, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiGetStatus, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiGetStatus, ora_ffi.c_long_ptr, ora_ffi.pls_pls_integer);
fh_BiDirectIO := ora_ffi.register_function(lh_EpsStmApi, 'BiDirectIO', ora_ffi.c_std);
ora_ffi.register_return(fh_BiDirectIO, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIO, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIO, ora_ffi.c_short, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIO, ora_ffi.c_char_ptr, ora_ffi.pls_varchar2);
ora_ffi.register_parameter(fh_BiDirectIO, ora_ffi.c_short_ptr, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIO, ora_ffi.c_char_ptr, ora_ffi.pls_varchar2);
ora_ffi.register_parameter(fh_BiDirectIO, ora_ffi.c_long, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIO, ora_ffi.c_short, ora_ffi.pls_pls_integer);
fh_BiDirectIOEx := ora_ffi.register_function(lh_EpsStmApi, 'BiDirectIOEx', ora_ffi.c_std);
ora_ffi.register_return(fh_BiDirectIOEx, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_int, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_long, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_char_ptr, ora_ffi.pls_varchar2);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_long_ptr, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_char_ptr, ora_ffi.pls_varchar2);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_long, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_short, ora_ffi.pls_pls_integer);
ora_ffi.register_parameter(fh_BiDirectIOEx, ora_ffi.c_short, ora_ffi.pls_pls_integer);
v_EPSON_LIBRARY_OK := TRUE;
END IF;
EXCEPTION
     WHEN OTHERS THEN
          AFC_MESSAGES('I','MAIN-0021','E',v_msg_b);
          v_EPSON_LIBRARY_OK := FALSE;
END;

Answer 1

Hi Duncan,
Thanks for the response. Beyond the problem you pointed out I found that the "open server" command is requiring a window handle parameter, even though it isn't used by the program. I talked with Oracle Support and it turns out that even if the window handle isn't used, it's existence makes it not work with the current version of webutil.
The program I am working with also has a COM interface, so I decided to back up and redo the interface using webutil OLE2. I've got it working now, just a little more polishing to do.
Thanks again for the help.
Mark