sane-project-backends/backend/plustek.c

/*.............................................................................
 * Project : SANE library for Plustek flatbed scanners.
 *.............................................................................
 */
 
/** @file plustek.c
 *  @brief SANE backend for Plustek scanner
 *
 * Based on Kazuhiro Sasayama previous work on
 * plustek.[ch] file from the SANE package.<br>
 * Original code taken from sane-0.71<br>
 * Copyright (C) 1997 Hypercore Software Design, Ltd.<br>
 * Also based on the work done by Rick Bronson<br>
 * Copyright (C) 2000-2003 Gerhard Jaeger <gerhard@gjaeger.de><br>
 *
 * History:
 * - 0.30 - initial version
 * - 0.31 - no changes
 * - 0.32 - no changes
 * - 0.33 - no changes
 * - 0.34 - moved some definitions and typedefs to plustek.h
 * - 0.35 - removed Y-correction for 12000P model<br>
 *        -  getting Y-size of scan area from driver
 * - 0.36 - disabled Dropout, as this does currently not work<br>
 *        - enabled Halftone selection only for Halftone-mode<br>
 *        - made the cancel button work by using a child process during read<br>
 *        - added version code to driver interface<br>
 *        - cleaned up the code<br>
 *        - fixed sane compatibility problems<br>
 *        - added multiple device support<br>
 *        - 12bit color-depth are now available for scanimage
 * - 0.37 - removed X/Y autocorrection, now correcting the stuff
 *          before scanning
 *        - applied Michaels' patch to solve the sane_get_parameter problem<br>
 *        - getting X-size of scan area from driver<br>
 *        - applied Michaels patch for OPT_RESOLUTION (SANE_INFO_INEXACT stuff)
 * - 0.38 - now using the information from the driver
 *        - some minor fixes<br>
 *        - removed dropout stuff<br>
 *        - removed some warning conditions
 * - 0.39 - added stuff to use the backend completely in user mode<br>
 *        - fixed a potential buffer problem<br>
 *        - removed function attach_one()<br>
 *        - added USB interface stuff
 * - 0.40 - USB scanning works now
 * - 0.41 - added some configuration stuff and also changed .conf file<br>
 *        - added call to sanei_usb_init() and sanei_lm983x_init()
 * - 0.42 - added adjustment stuff<br>
 *        - added custom gamma tables<br>
 *        - fixed a problem with the "size-sliders"<br>
 *        - fixed a bug that causes segfault when using the autodetection for
 *          USB devices<br>
 *        - added OS/2 switch to disable the USB stuff for OS/2
 * - 0.43 - added support for PREVIEW flag
 * - 0.44 - added _DBG_DUMP debug level<br>
 *        - fixed a bug, that stops our lamp timer
 * - 0.45 - added additional flags
 *        - added WIFSIGNALED to check result of child termination
 *        - changed readImage interface for USB devices
 *        - homeing of USB scanner is now working correctly
 * - 0.46 - added plustek-usbcal.c for extra CIS device calibration
 *          based in Montys' great work
 *        - added altCalibration option
 *        - removed parallelport support --> new backend: plustek_pp
 *        - cleanup
 *.
 * <hr>
 * This file is part of the SANE package.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 *
 * As a special exception, the authors of SANE give permission for
 * additional uses of the libraries contained in this release of SANE.
 *
 * The exception is that, if you link a SANE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License.  Your use of that executable is in no way restricted on
 * account of linking the SANE library code into it.
 *
 * This exception does not, however, invalidate any other reasons why
 * the executable file might be covered by the GNU General Public
 * License.
 *
 * If you submit changes to SANE to the maintainers to be included in
 * a subsequent release, you agree by submitting the changes that
 * those changes may be distributed with this exception intact.
 *
 * If you write modifications of your own for SANE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.
 * <hr>
 */

/** @mainpage
 *  @verbinclude Plustek-USB.txt
 */
  
#ifdef _AIX
# include <lalloca.h>		/* MUST come first for AIX! */
#endif

#include "sane/config.h"
#include <lalloca.h>

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <time.h>
#include <math.h>

#include <sys/time.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/ioctl.h>

#include "sane/sane.h"
#include "sane/sanei.h"
#include "sane/saneopts.h"

#define BACKEND_VERSION "0.46-2"
#define BACKEND_NAME	plustek
#include "sane/sanei_backend.h"
#include "sane/sanei_config.h"

/** might be used to disable all USB stuff - esp. for OS/2 */
#ifndef HAVE_OS2_H
# define _PLUSTEK_USB
#endif

#include "plustek-usb.h"
#include "plustek.h"

/*********************** the debug levels ************************************/

#define _DBG_FATAL      0
#define _DBG_ERROR      1
#define _DBG_WARNING    3
#define _DBG_INFO       5
#define _DBG_PROC       7
#define _DBG_SANE_INIT 10
#define _DBG_INFO2     13
#define _DBG_DUMP      20
#define _DBG_READ      25

/*****************************************************************************/

#define _SECTION        "[merlin-device]"
#define _DEFAULT_DEVICE "auto"

/* declare it here, as it's used in plustek-usbscan.c too :-( */
static SANE_Bool cancelRead;

/* the USB-stuff... I know this is in general no good idea, but it works */
#ifdef _PLUSTEK_USB

# include "plustek-usbio.c"
# include "plustek-usbdevs.c"
# include "plustek-usbhw.c"
# include "plustek-usbmap.c"
# include "plustek-usbscan.c"
# include "plustek-usbimg.c"
# include "plustek-usbcalfile.c"
# include "plustek-usbshading.c"
# include "plustek-usbcal.c"
# include "plustek-usb.c"
#endif

/************************** global vars **************************************/

static int                 num_devices;
static Plustek_Device     *first_dev;
static Plustek_Scanner    *first_handle;
static const SANE_Device **devlist = 0;
static unsigned long       tsecs   = 0;

static ModeParam mode_params[] =
{
  {0, 1,  COLOR_BW},
  {0, 8,  COLOR_256GRAY},
  {0, 16, COLOR_GRAY16},
  {1, 8,  COLOR_TRUE24},
  {1, 16, COLOR_TRUE48}
};

static const SANE_String_Const mode_usb_list[] =
{
	SANE_I18N("Binary"),
	SANE_I18N("Gray"),
	SANE_I18N("Gray 14/16"),
	SANE_I18N("Color"),
	SANE_I18N("Color 42/48"),
	NULL
};

static const SANE_String_Const ext_mode_list[] =
{
	SANE_I18N("Normal"),
	SANE_I18N("Transparency"),
	SANE_I18N("Negative"),
	NULL
};

static const SANE_Range percentage_range =
{
	-100 << SANE_FIXED_SCALE_SHIFT, /* minimum 		*/
	 100 << SANE_FIXED_SCALE_SHIFT, /* maximum 		*/
	   1 << SANE_FIXED_SCALE_SHIFT  /* quantization */
};

/* authorization stuff */
static SANE_Auth_Callback auth = NULL;

/****************************** the backend... *******************************/

#define _YN(x) (x?"yes":"no")

/**
 * function to display the configuration options for the current device
 * @param cnf - pointer to the configuration structure whose content should be
 *              displayed
 */
static void show_cnf( pCnfDef cnf )
{
	DBG( _DBG_SANE_INIT,"Device configuration:\n" );
	DBG( _DBG_SANE_INIT,"device name  : >%s<\n",cnf->devName                 );
	DBG( _DBG_SANE_INIT,"USB-ID       : >%s<\n",cnf->usbId                   );
	DBG( _DBG_SANE_INIT,"warmup       : %ds\n", cnf->adj.warmup              );
	DBG( _DBG_SANE_INIT,"lampOff      : %d\n",  cnf->adj.lampOff             );
	DBG( _DBG_SANE_INIT,"lampOffOnEnd : %s\n",  _YN(cnf->adj.lampOffOnEnd   ));
	DBG( _DBG_SANE_INIT,"cacheCalData : %s\n",  _YN(cnf->adj.cacheCalData   ));
	DBG( _DBG_SANE_INIT,"altCalibrate : %s\n",  _YN(cnf->adj.altCalibrate   ));
	DBG( _DBG_SANE_INIT,"skipCalibr.  : %s\n",  _YN(cnf->adj.skipCalibration));
	DBG( _DBG_SANE_INIT,"skipFine     : %s\n",  _YN(cnf->adj.skipFine       ));
	DBG( _DBG_SANE_INIT,"skipFineWhite: %s\n",  _YN(cnf->adj.skipFineWhite  ));
	DBG( _DBG_SANE_INIT,"invertNegs.  : %s\n",  _YN(cnf->adj.invertNegatives));
	DBG( _DBG_SANE_INIT,"pos_x        : %d\n",  cnf->adj.pos.x               );
	DBG( _DBG_SANE_INIT,"pos_y        : %d\n",  cnf->adj.pos.y               );
	DBG( _DBG_SANE_INIT,"pos_shading_y: %d\n",  cnf->adj.posShadingY         );
	DBG( _DBG_SANE_INIT,"neg_x        : %d\n",  cnf->adj.neg.x               );
	DBG( _DBG_SANE_INIT,"neg_y        : %d\n",  cnf->adj.neg.y               );
	DBG( _DBG_SANE_INIT,"neg_shading_y: %d\n",  cnf->adj.negShadingY         );
	DBG( _DBG_SANE_INIT,"tpa_x        : %d\n",  cnf->adj.tpa.x               );
	DBG( _DBG_SANE_INIT,"tpa_y        : %d\n",  cnf->adj.tpa.y               );
	DBG( _DBG_SANE_INIT,"tpa_shading_y: %d\n",  cnf->adj.tpaShadingY         );
	DBG( _DBG_SANE_INIT,"red gain     : %d\n",  cnf->adj.rgain               );
	DBG( _DBG_SANE_INIT,"green gain   : %d\n",  cnf->adj.ggain               );
	DBG( _DBG_SANE_INIT,"blue gain    : %d\n",  cnf->adj.bgain               );
	DBG( _DBG_SANE_INIT,"red Gamma    : %.2f\n",cnf->adj.rgamma              );
	DBG( _DBG_SANE_INIT,"green Gamma  : %.2f\n",cnf->adj.ggamma              );
	DBG( _DBG_SANE_INIT,"blue Gamma   : %.2f\n",cnf->adj.bgamma              );
	DBG( _DBG_SANE_INIT,"gray Gamma   : %.2f\n",cnf->adj.graygamma           );
	DBG( _DBG_SANE_INIT,"---------------------\n" );
}

/** open the device specific driver and reset the internal timing stuff
 * @param  dev - pointer to the device specific structure
 * @return the function returns the result of the open call, on success
 *         of course the handle
 */
static int drvopen(	Plustek_Device *dev )
{
	int handle;

    DBG( _DBG_INFO, "drvopen()\n" );

	handle = dev->open((const char*)dev->name, (void *)dev );

	tsecs = 0;

	return handle;
}

/** Calls the device specific stop and close functions.
 * @param  dev - pointer to the device specific structure
 * @return The function always returns SANE_STATUS_GOOD
 */
static SANE_Status drvclose( Plustek_Device *dev )
{
	int int_cnt;

	if( dev->fd >= 0 ) {

	    DBG( _DBG_INFO, "drvclose()\n" );

		if( 0 != tsecs ) {
			DBG( _DBG_INFO, "TIME END 1: %lus\n", time(NULL)-tsecs);
		}

		/*
		 * don't check the return values, simply do it and close the driver
		 */
		int_cnt = 0;
		dev->stopScan( dev, &int_cnt );
		dev->close( dev );
	}
	dev->fd = -1;

	return SANE_STATUS_GOOD;
}

/** according to the mode and source we return the corresponding mode list
 */
static pModeParam getModeList( Plustek_Scanner *scanner )
{
	pModeParam mp= mode_params;

	/*
	 * the transparency/negative mode supports only GRAY/COLOR/COLOR32/COLOR48
	 */
	if( 0 != scanner->val[OPT_EXT_MODE].w ) {
		mp = &mp[_TPAModeSupportMin];
	}		

	return mp;
}

/** function to check what our reader process returns. If the
 * process didn't exist, we can be sure, that we had any other problems
 */
static SANE_Bool getReaderProcessExitCode( Plustek_Scanner *scanner )
{
    int res;
    int status;

    scanner->exit_code = SANE_STATUS_IO_ERROR;

	if( scanner->reader_pid > 0 ) {

        res = waitpid( scanner->reader_pid, &status, WNOHANG );

        if( res == scanner->reader_pid ) {

    		DBG( _DBG_INFO, "res=%i, status=%i\n",res,status );

            if( WIFEXITED( status )) {

                scanner->exit_code = WEXITSTATUS(status);
	    		DBG( _DBG_INFO, "Child WEXITSTATUS = %d\n",scanner->exit_code);

            } else {

				if( !WIFSIGNALED( status )) {
	                scanner->exit_code = SANE_STATUS_GOOD;
		    		DBG( _DBG_INFO, "Child termination okay\n" );
				} else {
		    		DBG( _DBG_ERROR, "Child terminated by signal %d\n",
															WTERMSIG(status));
				}				
            }

			scanner->reader_pid = -1;
            return SANE_TRUE;
        }
    }

    return SANE_FALSE;
}

/**
 */
static SANE_Status close_pipe( Plustek_Scanner *scanner )
{
	if( scanner->pipe >= 0 ) {

		DBG( _DBG_PROC, "close_pipe\n" );

		close( scanner->pipe );
		scanner->pipe = -1;
	}

	return SANE_STATUS_EOF;
}

/**
 */
static void sig_chldhandler( int signo )
{
	DBG( _DBG_PROC, "Child is down (signal=%d)\n", signo );
}

/** signal handler to kill the child process
 */
static RETSIGTYPE reader_process_sigterm_handler( int signo )
{
	DBG( _DBG_PROC, "reader_process: terminated by signal %d\n", signo );
	_exit( SANE_STATUS_GOOD );
}

static RETSIGTYPE usb_reader_process_sigterm_handler( int signo )
{
	DBG( _DBG_PROC, "reader_process: terminated by signal %d\n", signo );
	cancelRead = SANE_TRUE;
}

static RETSIGTYPE sigalarm_handler( int signo )
{
	_VAR_NOT_USED( signo );
	DBG( _DBG_PROC, "ALARM!!!\n" );
}

/** executed as a child process
 * read the data from the driver and send them to the parent process
 */
static int reader_process( Plustek_Scanner *scanner, int pipe_fd )		
{
	int              line;
	unsigned char   *buf;
	unsigned long    status;
	unsigned long    data_length;
	struct SIGACTION act;

	DBG( _DBG_PROC, "reader_process started\n" );

	/* install the signal handler */
	cancelRead = SANE_FALSE;

    sigemptyset(&(act.sa_mask));
    act.sa_flags = 0;

	act.sa_handler = reader_process_sigterm_handler;
	sigaction( SIGTERM, &act, 0 );
	
	act.sa_handler = usb_reader_process_sigterm_handler;
	sigaction( SIGUSR1, &act, 0 );

	data_length = scanner->params.lines * scanner->params.bytes_per_line;

	DBG( _DBG_PROC, "reader_process:"
					"starting to READ data (%lu bytes)\n", data_length );
	DBG( _DBG_PROC, "buf = 0x%08lx\n", (unsigned long)scanner->buf );

	if( NULL == scanner->buf ) {
		DBG( _DBG_FATAL, "NULL Pointer !!!!\n" );
		return SANE_STATUS_IO_ERROR;
	}
	
	/* here we read all data from the driver... */
	buf    = scanner->buf;
	status = scanner->hw->prepare( scanner->hw, buf );
	
	if( 0 == status ) {

		for( line = 0; line < scanner->params.lines; line++ ) {

			status = scanner->hw->readLine( scanner->hw );
			if((int)status < 0 ) {
				break;
			}

			write( pipe_fd, buf, scanner->params.bytes_per_line );
    		buf += scanner->params.bytes_per_line;
		}
	}

	/* on error, there's no need to clean up, as this is done by the parent */
	if((int)status < 0 ) {
		DBG( _DBG_ERROR, "read failed, status = %i, errno %i\n",
                                                          (int)status, errno );
		if( -9009 == (int)status )
			return SANE_STATUS_CANCELLED;
		
		if( errno == EBUSY )
			return SANE_STATUS_DEVICE_BUSY;

		return SANE_STATUS_IO_ERROR;
	}

	pipe_fd = -1;

	DBG( _DBG_PROC, "reader_process: finished reading data\n" );
	return SANE_STATUS_GOOD;
}

/** stop the current scan process
 */
static SANE_Status do_cancel( Plustek_Scanner *scanner, SANE_Bool closepipe  )
{
	struct SIGACTION act;
	pid_t            res;

	DBG( _DBG_PROC,"do_cancel\n" );

	scanner->scanning = SANE_FALSE;

	if( scanner->reader_pid > 0 ) {

		DBG( _DBG_PROC, ">>>>>>>> killing reader_process <<<<<<<<\n" );

		cancelRead = SANE_TRUE;

	    sigemptyset(&(act.sa_mask));
    	act.sa_flags = 0;

		act.sa_handler = sigalarm_handler;
		sigaction( SIGALRM, &act, 0 );
	
		/* kill our child process and wait until done */
		kill( scanner->reader_pid, SIGUSR1 );

		/* give'em 10 seconds 'til done...*/			
		alarm(10);					
		res = waitpid( scanner->reader_pid, 0, 0 );
		alarm(0);					
		
		if( res != scanner->reader_pid ) {
			DBG( _DBG_PROC,"waitpid() failed !\n");
			kill( scanner->reader_pid, SIGKILL );
		}			

		scanner->reader_pid = 0;
		DBG( _DBG_PROC,"reader_process killed\n");
	}

	if( SANE_TRUE == closepipe ) {
		close_pipe( scanner );
	}

	drvclose( scanner->hw );

	if( tsecs != 0 ) {
		DBG( _DBG_INFO, "TIME END 2: %lus\n", time(NULL)-tsecs);
		tsecs = 0;
	}

	return SANE_STATUS_CANCELLED;
}

/** because of some internal problems (inside the parport driver), we have to
 * limit the max resolution to optical resolution. This is done by this
 * function
 * @param  dev - pointer to the device specific structure
 * @return The function always returns SANE_STATUS_GOOD
 */
static SANE_Status limitResolution( Plustek_Device *dev )
{
	dev->dpi_range.min = _DEF_DPI;
 	if( dev->dpi_range.min < _DEF_DPI )
		dev->dpi_range.min = _DEF_DPI;

	dev->dpi_range.max   = dev->usbDev.Caps.OpticDpi.x * 2;
	dev->dpi_range.quant = 0;
	dev->x_range.min 	 = 0;
	dev->x_range.max 	 = SANE_FIX(dev->max_x);
	dev->x_range.quant 	 = 0;
	dev->y_range.min 	 = 0;
	dev->y_range.max 	 = SANE_FIX(dev->max_y);
	dev->y_range.quant 	 = 0;
	
	return SANE_STATUS_GOOD;
}

/** Currently we support only LM9831/2/3 chips and these use the same
 * sizes...
 * @param  s - pointer to the scanner specific structure
 * @return The function always returns SANE_STATUS_GOOD
 */
static SANE_Status initGammaSettings( Plustek_Scanner *s )
{
	int    i, j, val;
	double gamma;

	/*
     * this setting is common to the ASIC98001/3 and
     * LM9831/2/3 based devices
     * older parallelport devices use 256 entries
     */
	s->gamma_length      = 4096;
  	s->gamma_range.min   = 0;
  	s->gamma_range.max   = 255;
  	s->gamma_range.quant = 0;

  	DBG( _DBG_INFO, "Presetting Gamma tables (len=%u)\n", s->gamma_length );
  	DBG( _DBG_INFO, "----------------------------------\n" );
  	
  	/*
  	 * preset the gamma maps
  	 */
  	for( i = 0; i < 4; i++ ) {
			
		switch( i ) {
			case 1:  gamma = s->hw->adj.rgamma;    break;
			case 2:  gamma = s->hw->adj.ggamma;    break;
			case 3:  gamma = s->hw->adj.bgamma;    break;
			default: gamma = s->hw->adj.graygamma; break;
		}			
  	
		for( j = 0; j < s->gamma_length; j++ ) {
		
			val = (s->gamma_range.max *
					    pow((double) j / ((double)s->gamma_length - 1.0),
						1.0 / gamma ));
			
			if( val > s->gamma_range.max )
				val = s->gamma_range.max;
												
			s->gamma_table[i][j] = val;					
		}			
	}			
	
	return SANE_STATUS_GOOD;
}  	

/** Check the gamma vectors we got back and limit if necessary
 * @param  s - pointer to the scanner specific structure
 * @return nothing
 */
static void checkGammaSettings( Plustek_Scanner *s )
{
	int i, j;
  	
  	for( i = 0; i < 4 ; i++ ) {
		for( j = 0; j < s->gamma_length; j++ ) {
			if( s->gamma_table[i][j] > s->gamma_range.max ) {
				s->gamma_table[i][j] = s->gamma_range.max;
			}
		}	
	}	
}

/** initialize the options for the backend according to the device we have
 */
static SANE_Status init_options( Plustek_Scanner *s )
{
	int i;

	memset( s->opt, 0, sizeof(s->opt));

	for( i = 0; i < NUM_OPTIONS; ++i ) {
		s->opt[i].size = sizeof (SANE_Word);
		s->opt[i].cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
    }

	s->opt[OPT_NUM_OPTS].name  = SANE_NAME_NUM_OPTIONS;
	s->opt[OPT_NUM_OPTS].title = SANE_TITLE_NUM_OPTIONS;
	s->opt[OPT_NUM_OPTS].desc  = SANE_DESC_NUM_OPTIONS;
	s->opt[OPT_NUM_OPTS].type  = SANE_TYPE_INT;
	s->opt[OPT_NUM_OPTS].unit  = SANE_UNIT_NONE;
	s->opt[OPT_NUM_OPTS].cap   = SANE_CAP_SOFT_DETECT;
	s->opt[OPT_NUM_OPTS].constraint_type = SANE_CONSTRAINT_NONE;
	s->val[OPT_NUM_OPTS].w 	   = NUM_OPTIONS;

	/* "Scan Mode" group: */
	s->opt[OPT_MODE_GROUP].name  = "scanmode-group";
	s->opt[OPT_MODE_GROUP].title = SANE_I18N("Scan Mode");
	s->opt[OPT_MODE_GROUP].desc  = "";
	s->opt[OPT_MODE_GROUP].type  = SANE_TYPE_GROUP;
	s->opt[OPT_MODE_GROUP].cap   = 0;

	/* scan mode */
	s->opt[OPT_MODE].name  = SANE_NAME_SCAN_MODE;
	s->opt[OPT_MODE].title = SANE_TITLE_SCAN_MODE;
	s->opt[OPT_MODE].desc  = SANE_DESC_SCAN_MODE;
	s->opt[OPT_MODE].type  = SANE_TYPE_STRING;
	s->opt[OPT_MODE].size  = 32;
	s->opt[OPT_MODE].constraint_type = SANE_CONSTRAINT_STRING_LIST;
	s->opt[OPT_MODE].constraint.string_list = mode_usb_list;
	s->val[OPT_MODE].w = 3;		/* Color */

	/* scan source */
	s->opt[OPT_EXT_MODE].name  = SANE_NAME_SCAN_SOURCE;
	s->opt[OPT_EXT_MODE].title = SANE_TITLE_SCAN_SOURCE;
	s->opt[OPT_EXT_MODE].desc  = SANE_DESC_SCAN_SOURCE;
	s->opt[OPT_EXT_MODE].type  = SANE_TYPE_STRING;
	s->opt[OPT_EXT_MODE].size  = 32;
	s->opt[OPT_EXT_MODE].constraint_type = SANE_CONSTRAINT_STRING_LIST;
	s->opt[OPT_EXT_MODE].constraint.string_list = ext_mode_list;
	s->val[OPT_EXT_MODE].w = 0; /* Normal */
	
	/* brightness */
	s->opt[OPT_BRIGHTNESS].name  = SANE_NAME_BRIGHTNESS;
	s->opt[OPT_BRIGHTNESS].title = SANE_TITLE_BRIGHTNESS;
	s->opt[OPT_BRIGHTNESS].desc  = SANE_DESC_BRIGHTNESS;
	s->opt[OPT_BRIGHTNESS].type  = SANE_TYPE_FIXED;
	s->opt[OPT_BRIGHTNESS].unit  = SANE_UNIT_PERCENT;
	s->opt[OPT_BRIGHTNESS].constraint_type = SANE_CONSTRAINT_RANGE;
	s->opt[OPT_BRIGHTNESS].constraint.range = &percentage_range;
	s->val[OPT_BRIGHTNESS].w     = 0;

	/* contrast */
	s->opt[OPT_CONTRAST].name  = SANE_NAME_CONTRAST;
	s->opt[OPT_CONTRAST].title = SANE_TITLE_CONTRAST;
	s->opt[OPT_CONTRAST].desc  = SANE_DESC_CONTRAST;
	s->opt[OPT_CONTRAST].type  = SANE_TYPE_FIXED;
	s->opt[OPT_CONTRAST].unit  = SANE_UNIT_PERCENT;
	s->opt[OPT_CONTRAST].constraint_type = SANE_CONSTRAINT_RANGE;
	s->opt[OPT_CONTRAST].constraint.range = &percentage_range;
	s->val[OPT_CONTRAST].w     = 0;

	/* resolution */
	s->opt[OPT_RESOLUTION].name  = SANE_NAME_SCAN_RESOLUTION;
	s->opt[OPT_RESOLUTION].title = SANE_TITLE_SCAN_RESOLUTION;
	s->opt[OPT_RESOLUTION].desc  = SANE_DESC_SCAN_RESOLUTION;
	s->opt[OPT_RESOLUTION].type  = SANE_TYPE_INT;
	s->opt[OPT_RESOLUTION].unit  = SANE_UNIT_DPI;

	s->opt[OPT_RESOLUTION].constraint_type  = SANE_CONSTRAINT_RANGE;
	s->opt[OPT_RESOLUTION].constraint.range = &s->hw->dpi_range;
	s->val[OPT_RESOLUTION].w = s->hw->dpi_range.min;

	/* custom-gamma table */
  	s->opt[OPT_CUSTOM_GAMMA].name  = SANE_NAME_CUSTOM_GAMMA;
  	s->opt[OPT_CUSTOM_GAMMA].title = SANE_TITLE_CUSTOM_GAMMA;
  	s->opt[OPT_CUSTOM_GAMMA].desc  = SANE_DESC_CUSTOM_GAMMA;
  	s->opt[OPT_CUSTOM_GAMMA].type  = SANE_TYPE_BOOL;
  	s->val[OPT_CUSTOM_GAMMA].w     = SANE_FALSE;

	/* preview */
	s->opt[OPT_PREVIEW].name = SANE_NAME_PREVIEW;
	s->opt[OPT_PREVIEW].title = SANE_TITLE_PREVIEW;
	s->opt[OPT_PREVIEW].desc = SANE_DESC_PREVIEW;
	s->opt[OPT_PREVIEW].cap = SANE_CAP_SOFT_DETECT | SANE_CAP_SOFT_SELECT;
	s->val[OPT_PREVIEW].w = 0;

	/* "Geometry" group: */
	s->opt[OPT_GEOMETRY_GROUP].name  = "geometry-group";
	s->opt[OPT_GEOMETRY_GROUP].title = SANE_I18N("Geometry");
	s->opt[OPT_GEOMETRY_GROUP].desc  = "";
	s->opt[OPT_GEOMETRY_GROUP].type  = SANE_TYPE_GROUP;
	s->opt[OPT_GEOMETRY_GROUP].cap   = SANE_CAP_ADVANCED;

	/* top-left x */
	s->opt[OPT_TL_X].name  = SANE_NAME_SCAN_TL_X;
	s->opt[OPT_TL_X].title = SANE_TITLE_SCAN_TL_X;
	s->opt[OPT_TL_X].desc  = SANE_DESC_SCAN_TL_X;
	s->opt[OPT_TL_X].type  = SANE_TYPE_FIXED;
	s->opt[OPT_TL_X].unit  = SANE_UNIT_MM;
	s->opt[OPT_TL_X].constraint_type = SANE_CONSTRAINT_RANGE;
	s->opt[OPT_TL_X].constraint.range = &s->hw->x_range;
	s->val[OPT_TL_X].w = SANE_FIX(_DEFAULT_TLX);

	/* top-left y */
	s->opt[OPT_TL_Y].name  = SANE_NAME_SCAN_TL_Y;
	s->opt[OPT_TL_Y].title = SANE_TITLE_SCAN_TL_Y;
	s->opt[OPT_TL_Y].desc  = SANE_DESC_SCAN_TL_Y;
	s->opt[OPT_TL_Y].type  = SANE_TYPE_FIXED;
	s->opt[OPT_TL_Y].unit  = SANE_UNIT_MM;
	s->opt[OPT_TL_Y].constraint_type = SANE_CONSTRAINT_RANGE;
	s->opt[OPT_TL_Y].constraint.range = &s->hw->y_range;
	s->val[OPT_TL_Y].w = SANE_FIX(_DEFAULT_TLY);

	/* bottom-right x */
	s->opt[OPT_BR_X].name  = SANE_NAME_SCAN_BR_X;
	s->opt[OPT_BR_X].title = SANE_TITLE_SCAN_BR_X;
	s->opt[OPT_BR_X].desc  = SANE_DESC_SCAN_BR_X;
	s->opt[OPT_BR_X].type  = SANE_TYPE_FIXED;
	s->opt[OPT_BR_X].unit  = SANE_UNIT_MM;
	s->opt[OPT_BR_X].constraint_type = SANE_CONSTRAINT_RANGE;
	s->opt[OPT_BR_X].constraint.range = &s->hw->x_range;
	s->val[OPT_BR_X].w = SANE_FIX(_DEFAULT_BRX);

	/* bottom-right y */
	s->opt[OPT_BR_Y].name  = SANE_NAME_SCAN_BR_Y;
	s->opt[OPT_BR_Y].title = SANE_TITLE_SCAN_BR_Y;
	s->opt[OPT_BR_Y].desc  = SANE_DESC_SCAN_BR_Y;
	s->opt[OPT_BR_Y].type  = SANE_TYPE_FIXED;
	s->opt[OPT_BR_Y].unit  = SANE_UNIT_MM;
	s->opt[OPT_BR_Y].constraint_type = SANE_CONSTRAINT_RANGE;
	s->opt[OPT_BR_Y].constraint.range = &s->hw->y_range;
	s->val[OPT_BR_Y].w = SANE_FIX(_DEFAULT_BRY);

	/* "Enhancement" group: */
	s->opt[OPT_ENHANCEMENT_GROUP].title = SANE_I18N("Enhancement");	
	s->opt[OPT_ENHANCEMENT_GROUP].desc = "";
	s->opt[OPT_ENHANCEMENT_GROUP].type = SANE_TYPE_GROUP;
	s->opt[OPT_ENHANCEMENT_GROUP].cap = 0;
	s->opt[OPT_ENHANCEMENT_GROUP].constraint_type = SANE_CONSTRAINT_NONE;
	
	initGammaSettings( s );
	
 	/* grayscale gamma vector */
  	s->opt[OPT_GAMMA_VECTOR].name  = SANE_NAME_GAMMA_VECTOR;
  	s->opt[OPT_GAMMA_VECTOR].title = SANE_TITLE_GAMMA_VECTOR;
  	s->opt[OPT_GAMMA_VECTOR].desc  = SANE_DESC_GAMMA_VECTOR;
  	s->opt[OPT_GAMMA_VECTOR].type  = SANE_TYPE_INT;
  	s->opt[OPT_GAMMA_VECTOR].unit  = SANE_UNIT_NONE;
  	s->opt[OPT_GAMMA_VECTOR].constraint_type = SANE_CONSTRAINT_RANGE;
  	s->val[OPT_GAMMA_VECTOR].wa = &(s->gamma_table[0][0]);
  	s->opt[OPT_GAMMA_VECTOR].constraint.range = &(s->gamma_range);
  	s->opt[OPT_GAMMA_VECTOR].size = s->gamma_length * sizeof(SANE_Word);

	/* red gamma vector */
  	s->opt[OPT_GAMMA_VECTOR_R].name  = SANE_NAME_GAMMA_VECTOR_R;
  	s->opt[OPT_GAMMA_VECTOR_R].title = SANE_TITLE_GAMMA_VECTOR_R;
  	s->opt[OPT_GAMMA_VECTOR_R].desc  = SANE_DESC_GAMMA_VECTOR_R;
  	s->opt[OPT_GAMMA_VECTOR_R].type  = SANE_TYPE_INT;
  	s->opt[OPT_GAMMA_VECTOR_R].unit  = SANE_UNIT_NONE;
  	s->opt[OPT_GAMMA_VECTOR_R].constraint_type = SANE_CONSTRAINT_RANGE;
  	s->val[OPT_GAMMA_VECTOR_R].wa = &(s->gamma_table[1][0]);
  	s->opt[OPT_GAMMA_VECTOR_R].constraint.range = &(s->gamma_range);
  	s->opt[OPT_GAMMA_VECTOR_R].size = s->gamma_length * sizeof(SANE_Word);

  	/* green gamma vector */
  	s->opt[OPT_GAMMA_VECTOR_G].name  = SANE_NAME_GAMMA_VECTOR_G;
  	s->opt[OPT_GAMMA_VECTOR_G].title = SANE_TITLE_GAMMA_VECTOR_G;
  	s->opt[OPT_GAMMA_VECTOR_G].desc  = SANE_DESC_GAMMA_VECTOR_G;
  	s->opt[OPT_GAMMA_VECTOR_G].type  = SANE_TYPE_INT;
  	s->opt[OPT_GAMMA_VECTOR_G].unit  = SANE_UNIT_NONE;
  	s->opt[OPT_GAMMA_VECTOR_G].constraint_type = SANE_CONSTRAINT_RANGE;
  	s->val[OPT_GAMMA_VECTOR_G].wa = &(s->gamma_table[2][0]);
  	s->opt[OPT_GAMMA_VECTOR_G].constraint.range = &(s->gamma_range);
  	s->opt[OPT_GAMMA_VECTOR_G].size = s->gamma_length * sizeof(SANE_Word);

  	/* blue gamma vector */
  	s->opt[OPT_GAMMA_VECTOR_B].name  = SANE_NAME_GAMMA_VECTOR_B;
  	s->opt[OPT_GAMMA_VECTOR_B].title = SANE_TITLE_GAMMA_VECTOR_B;
  	s->opt[OPT_GAMMA_VECTOR_B].desc  = SANE_DESC_GAMMA_VECTOR_B;
  	s->opt[OPT_GAMMA_VECTOR_B].type  = SANE_TYPE_INT;
  	s->opt[OPT_GAMMA_VECTOR_B].unit  = SANE_UNIT_NONE;
  	s->opt[OPT_GAMMA_VECTOR_B].constraint_type = SANE_CONSTRAINT_RANGE;
  	s->val[OPT_GAMMA_VECTOR_B].wa = &(s->gamma_table[3][0]);
  	s->opt[OPT_GAMMA_VECTOR_B].constraint.range = &(s->gamma_range);
  	s->opt[OPT_GAMMA_VECTOR_B].size = s->gamma_length * sizeof(SANE_Word);

	/* GAMMA stuff is disabled per default */	
    s->opt[OPT_GAMMA_VECTOR].cap   |= SANE_CAP_INACTIVE;
    s->opt[OPT_GAMMA_VECTOR_R].cap |= SANE_CAP_INACTIVE;
    s->opt[OPT_GAMMA_VECTOR_G].cap |= SANE_CAP_INACTIVE;
    s->opt[OPT_GAMMA_VECTOR_B].cap |= SANE_CAP_INACTIVE;
	
	/* disable extended mode list for devices without TPA */
	if( 0 == (s->hw->caps.dwFlag & SFLAG_TPA)) {
		s->opt[OPT_EXT_MODE].cap |= SANE_CAP_INACTIVE;
	}

  	/* disable custom gamma, if not supported by the driver... */
	if( 0 == (s->hw->caps.dwFlag & SFLAG_CUSTOM_GAMMA)) {
	  	s->opt[OPT_CUSTOM_GAMMA].cap |= SANE_CAP_INACTIVE;
	}  		

	return SANE_STATUS_GOOD;
}

/** Function to retrieve the vendor and product id from a given string
 * @param src  - string, that should be investigated
 * @param dest - pointer to a string to receive the USB ID
 */
static void decodeUsbIDs( char *src, char **dest )
{		
	const char *name;	
	char       *tmp = *dest;
	int         len = strlen(_SECTION);

	if( isspace(src[len])) {
		strncpy( tmp, &src[len+1], (strlen(src)-(len+1)));
        tmp[(strlen(src)-(len+1))] = '\0';
	}

	name = tmp;
   	name = sanei_config_skip_whitespace( name );

	if( '\0' == name[0] ) {
		DBG( _DBG_SANE_INIT, "next device uses autodetection\n" );
	} else {
			
		u_short pi = 0, vi = 0;

		if( *name ) {
	
			name = sanei_config_get_string( name, &tmp );
			if( tmp ) {
		    	vi = strtol( tmp, 0, 0 );
			    free( tmp );
			}
	    }
				
		name = sanei_config_skip_whitespace( name );
     	if( *name ) {
		
			name = sanei_config_get_string( name, &tmp );
			if( tmp ) {
	      		pi = strtol( tmp, 0, 0 );
		    	free( tmp );
		    }
		}

		/* create what we need to go through our device list...*/			
		sprintf( *dest, "0x%04X-0x%04X", vi, pi );
		DBG( _DBG_SANE_INIT, "next device is a USB device (%s)\n", *dest );
	}	
}				

#define _INT   0
#define _FLOAT 1

/** function to decode an value and give it back to the caller.
 * @param src    -  pointer to the source string to check
 * @param opt    -  string that keeps the option name to check src for
 * @param what   - _FLOAT or _INT
 * @param result -  pointer to the var that should receive our result
 * @param def    - default value that result should be in case of any error
 * @return The function returns SANE_TRUE if the option has been found,
 *         if not, it returns SANE_FALSE
 */
static SANE_Bool decodeVal( char *src, char *opt,
							int what, void *result, void *def )
{
	char       *tmp, *tmp2;
	const char *name;

	/* skip the option string */
	name = (const char*)&src[strlen("option")];

	/* get the name of the option */
	name = sanei_config_get_string( name, &tmp );

	if( tmp ) {	

		/* on success, compare wiht the given one */
		if( 0 == strcmp( tmp, opt )) {
	
			DBG( _DBG_SANE_INIT, "Decoding option >%s<\n", opt );

			if( _INT == what ) {
			
				/* assign the default value for this option... */
				*((int*)result) = *((int*)def);
	
				if( *name ) {

					/* get the configuration value and decode it */
					name = sanei_config_get_string( name, &tmp2 );

					if( tmp2 ) {
		      			*((int*)result) = strtol( tmp2, 0, 0 );
				    	free( tmp2 );
					}
				}
				free( tmp );	
				return SANE_TRUE;
				
			} else if( _FLOAT == what ) {
			
				/* assign the default value for this option... */
				*((double*)result) = *((double*)def);
	
				if( *name ) {

					/* get the configuration value and decode it */
					name = sanei_config_get_string( name, &tmp2 );

					if( tmp2 ) {
		      			*((double*)result) = strtod( tmp2, 0 );
				    	free( tmp2 );
					}
				}
				free( tmp );	
				return SANE_TRUE;
			}
		}	
		free( tmp );
	}
	
   	return SANE_FALSE;
}

/** function to retrive the device name of a given string
 * @param src  -  string that keeps the option name to check src for
 * @param dest -  pointer to the string, that should receive the detected
 *                devicename
 * @return The function returns SANE_TRUE if the devicename has been found,
 *         if not, it returns SANE_FALSE
 */
static SANE_Bool decodeDevName( char *src, char *dest )
{
	char       *tmp;	
	const char *name;

	if( 0 == strncmp( "device", src, 6 )) {

		name = (const char*)&src[strlen("device")];
		name = sanei_config_skip_whitespace( name );
	
		DBG( _DBG_SANE_INIT, "Decoding device name >%s<\n", name );
		
		if( *name ) {
			name = sanei_config_get_string( name, &tmp );
			if( tmp ) {
	      		
				strcpy( dest, tmp );
		    	free( tmp );
		    	return SANE_TRUE;
		    }
		}	
	}
	
   	return SANE_FALSE;
}

/** attach a device to the backend
 */
static SANE_Status attach( const char *dev_name, pCnfDef cnf,
										                Plustek_Device **devp )
{
	int 		    cntr;
	int			    result;
	int			    handle;
	SANE_Status	    status;
	Plustek_Device *dev;

	DBG( _DBG_SANE_INIT, "attach (%s, %p, %p)\n",
	                                      dev_name, (void *)cnf, (void *)devp);

	/* already attached ?*/
	for( dev = first_dev; dev; dev = dev->next ) {

		if( 0 == strcmp( dev->sane.name, dev_name )) {
			if( devp )
        		*devp = dev;

    		return SANE_STATUS_GOOD;
        }
    }

	/* allocate some memory for the device */
	dev = malloc( sizeof (*dev));
	if( NULL == dev )
    	return SANE_STATUS_NO_MEM;

	/* assign all the stuff we need fo this device... */

	memset(dev, 0, sizeof (*dev));
	
	dev->fd			 = -1;
    dev->name        = strdup(dev_name);    /* hold it double to avoid  */
	dev->sane.name   = dev->name;           /* compiler warnings        */
	dev->sane.vendor = "Plustek";
	dev->initialized = -1;                  /* will be used as index too */
	dev->calFile     = NULL;

	memcpy( &dev->adj, &cnf->adj, sizeof(AdjDef));

	show_cnf( cnf );

	dev->sane.type = "USB flatbed scanner";

#ifdef _PLUSTEK_USB
	dev->open  	     = usbDev_open;
	dev->close 	     = usbDev_close;
	dev->getCaps     = usbDev_getCaps;
	dev->getCropInfo = usbDev_getCropInfo;
	dev->setScanEnv  = usbDev_setScanEnv;
	dev->startScan   = usbDev_startScan;
	dev->stopScan    = usbDev_stopScan;
	dev->setMap      = usbDev_setMap;
	dev->readLine    = usbDev_readLine;
	dev->prepare     = usbDev_Prepare;
	dev->shutdown    = usbDev_shutdown;

	strncpy( dev->usbId, cnf->usbId, _MAX_ID_LEN );
		
	if( cnf->adj.warmup >= 0 )
		dev->usbDev.dwWarmup = cnf->adj.warmup;
	
	if( cnf->adj.lampOff >= 0 )
		dev->usbDev.dwLampOnPeriod = cnf->adj.lampOff;

	if( cnf->adj.lampOffOnEnd >= 0 )
		dev->usbDev.bLampOffOnEnd = cnf->adj.lampOffOnEnd;
#else
	free( dev->name );
	free( dev );
	DBG( _DBG_ERROR, "Backend non-functional on this platform :-(\n" );
	return SANE_STATUS_INVAL;
#endif

	/*
	 * go ahead and open the scanner device
	 */
	handle = drvopen( dev );
	if( handle < 0 ) {
		DBG( _DBG_ERROR,"open failed: %d\n", handle );
		return SANE_STATUS_IO_ERROR;
    }

	/* okay, so assign the handle... */
	dev->fd = handle;

 	result = dev->getCaps( dev );
	if( result < 0 ) {
		DBG( _DBG_ERROR, "dev->getCaps() failed(%d)\n", result);
		dev->close(dev);
		return SANE_STATUS_IO_ERROR;
    }

	/* save the info we got from the driver */
	DBG( _DBG_INFO, "Scanner information:\n" );
#ifdef _PLUSTEK_USB
    if( NULL != dev->usbDev.ModelStr )
    	dev->sane.model = dev->usbDev.ModelStr;
	else
#endif
    	dev->sane.model = "USB-Device";
   	
   	DBG( _DBG_INFO, "Vendor : %s\n",      dev->sane.vendor  );
   	DBG( _DBG_INFO, "Model  : %s\n",      dev->sane.model   );
	DBG( _DBG_INFO, "Flags  : 0x%08lx\n", dev->caps.dwFlag  );

	dev->max_x = dev->caps.wMaxExtentX*MM_PER_INCH/_MEASURE_BASE;
	dev->max_y = dev->caps.wMaxExtentY*MM_PER_INCH/_MEASURE_BASE;

	/* calculate the size of the resolution list +
	 * one more to avoid a buffer overflow, then allocate it...
	 */
	dev->res_list = (SANE_Int *)
					calloc((((dev->usbDev.Caps.OpticDpi.x*16)-_DEF_DPI)/25+1),
						sizeof (SANE_Int));  

	if (NULL == dev->res_list) {
		DBG( _DBG_ERROR, "alloc fail, resolution problem\n" );
		dev->close(dev);
		return SANE_STATUS_INVAL;
	}

    /* build up the resolution table */
	dev->res_list_size = 0;
	for( cntr = _DEF_DPI; cntr <= (dev->usbDev.Caps.OpticDpi.x*16); cntr += 25 ) {
		dev->res_list_size++;
		dev->res_list[dev->res_list_size - 1] = (SANE_Int)cntr;
	}

	status = limitResolution( dev );

	dev->fd = handle;
	drvclose( dev );

	DBG( _DBG_SANE_INIT, "attach: model = >%s<\n", dev->sane.model );

	++num_devices;
	dev->next = first_dev;
	first_dev = dev;

	if (devp)
    	*devp = dev;

	return SANE_STATUS_GOOD;
}

/** function to preset a configuration structure
 * @param cnf - pointer to the structure that should be initialized
 */
static void init_config_struct( pCnfDef cnf )
{
    memset( cnf, 0, sizeof(CnfDef));

	cnf->adj.warmup       = -1;
	cnf->adj.lampOff      = -1;
	cnf->adj.lampOffOnEnd = -1;

	cnf->adj.posShadingY  = -1;
	cnf->adj.tpaShadingY  = -1;
	cnf->adj.negShadingY  = -1;
	cnf->adj.rgain        = -1;
	cnf->adj.ggain        = -1;
	cnf->adj.bgain        = -1;

	cnf->adj.graygamma = 1.0;
	cnf->adj.rgamma    = 1.0;
	cnf->adj.ggamma    = 1.0;
	cnf->adj.bgamma    = 1.0;
}

/** intialize the backend
 */
SANE_Status sane_init( SANE_Int *version_code, SANE_Auth_Callback authorize )
{
	char     str[PATH_MAX] = _DEFAULT_DEVICE;
    CnfDef   config;
	size_t   len;
	FILE    *fp;

	DBG_INIT();

#ifdef _PLUSTEK_USB
	sanei_usb_init();
	sanei_lm983x_init();
#endif	

#if defined PACKAGE && defined VERSION
	DBG( _DBG_SANE_INIT, "Plustek backend V"BACKEND_VERSION", part of "
												 PACKAGE " " VERSION "\n");
#else
	DBG( _DBG_INFO, "Plustek backend V"BACKEND_VERSION"\n" );
#endif

	/* do some presettings... */
	auth         = authorize;
	first_dev    = NULL;
	first_handle = NULL;
	num_devices  = 0;

	/* initialize the configuration structure */
	init_config_struct( &config );

	if( version_code != NULL )
		*version_code = SANE_VERSION_CODE(V_MAJOR, V_MINOR, 0);

	fp = sanei_config_open( PLUSTEK_CONFIG_FILE );

	/* default to _DEFAULT_DEVICE instead of insisting on config file */
	if( NULL == fp ) {
		return attach( _DEFAULT_DEVICE, &config, 0 );
	}

	while( sanei_config_read( str, sizeof(str), fp)) {
		
		DBG( _DBG_SANE_INIT, ">%s<\n", str );
		if( str[0] == '#')		/* ignore line comments */
    		continue;
			
		len = strlen(str);
		if( 0 == len )
           	continue;			    /* ignore empty lines */

		/* check for options */
		if( 0 == strncmp(str, "option", 6)) {
		
			int    ival;
			double dval;
		
			ival = -1;
			decodeVal( str, "warmup",    _INT, &config.adj.warmup,      &ival);
			decodeVal( str, "lampOff",   _INT, &config.adj.lampOff,     &ival);
			decodeVal( str, "lOffOnEnd", _INT, &config.adj.lampOffOnEnd,&ival);
			decodeVal( str, "posShadingY",_INT, &config.adj.posShadingY,&ival);
			decodeVal( str, "tpaShadingY",_INT, &config.adj.tpaShadingY,&ival);
			decodeVal( str, "negShadingY",_INT, &config.adj.negShadingY,&ival);
			decodeVal( str, "red_gain",   _INT, &config.adj.rgain,      &ival);
			decodeVal( str, "green_gain", _INT, &config.adj.ggain,      &ival);
			decodeVal( str, "blue_gain",  _INT, &config.adj.bgain,      &ival);
			
			ival = 0;
			decodeVal( str, "enableTPA", _INT, &config.adj.enableTpa, &ival);
			decodeVal( str, "cacheCalData",
									     _INT, &config.adj.cacheCalData,&ival);
			decodeVal( str, "altCalibration",
									     _INT, &config.adj.altCalibrate,&ival);
			decodeVal( str, "skipCalibration",
									  _INT, &config.adj.skipCalibration,&ival);
			decodeVal( str, "skipFine",
									  _INT, &config.adj.skipFine,&ival);
			decodeVal( str, "skipFineWhite",
									  _INT, &config.adj.skipFineWhite,&ival);
			decodeVal( str, "invertNegatives",
									  _INT, &config.adj.invertNegatives,&ival);

			decodeVal( str, "posOffX", _INT, &config.adj.pos.x, &ival );
			decodeVal( str, "posOffY", _INT, &config.adj.pos.y, &ival );

			decodeVal( str, "negOffX", _INT, &config.adj.neg.x, &ival );
			decodeVal( str, "negOffY", _INT, &config.adj.neg.y, &ival );

			decodeVal( str, "tpaOffX", _INT, &config.adj.tpa.x, &ival );
			decodeVal( str, "tpaOffY", _INT, &config.adj.tpa.y, &ival );
			
			dval = 1.0;
			decodeVal( str, "grayGamma",  _FLOAT, &config.adj.graygamma,&dval);
			decodeVal( str, "redGamma",   _FLOAT, &config.adj.rgamma, &dval );
			decodeVal( str, "greenGamma", _FLOAT, &config.adj.ggamma, &dval );
			decodeVal( str, "blueGamma",  _FLOAT, &config.adj.bgamma, &dval );
			continue;

		/* check for sections: */
		} else if( 0 == strncmp( str, _SECTION, strlen(_SECTION))) {
		
		    char *tmp;
		
		    /* new section, try and attach previous device */
		    if( config.devName[0] != '\0' ) {
				attach( config.devName, &config, 0 );
			} else {
				DBG( _DBG_WARNING, "section contains no device name,"
				                   " ignored!\n" );
			}
		
			/* re-initialize the configuration structure */
			init_config_struct( &config );
		
		    tmp = config.usbId;
			decodeUsbIDs( str, &tmp );
		
			DBG( _DBG_SANE_INIT, "... next device\n" );
			continue;				

		} else if( SANE_TRUE == decodeDevName( str, config.devName )) {
			continue;
		}
		
		/* ignore other stuff... */
		DBG( _DBG_SANE_INIT, "ignoring >%s<\n", str );
	}
   	fclose (fp);

    /* try to attach the last device in the config file... */
    if( config.devName[0] != '\0' )
		attach( config.devName, &config, 0 );
   	
	return SANE_STATUS_GOOD;
}

/** cleanup the backend...
 */
void sane_exit( void )
{
	Plustek_Device *dev, *next;

	DBG( _DBG_SANE_INIT, "sane_exit\n" );

	for( dev = first_dev; dev; ) {

    	next = dev->next;

		/* call the shutdown function of each device... */
		if( dev->shutdown )
			dev->shutdown( dev );

        /*
         * we're doin' this to avoid compiler warnings as dev->sane.name
         * is defined as const char*
         */
		if( dev->sane.name )
			free( dev->name );

		if( dev->calFile )
			free( dev->calFile );
		
        if( dev->res_list )
			free( dev->res_list );
		free( dev );

		dev = next;
	}

	if( devlist )
    	free( devlist );

    devlist      = NULL;
	auth         = NULL;
	first_dev    = NULL;
	first_handle = NULL;
}

/** return a list of all devices
 */
SANE_Status sane_get_devices(const SANE_Device ***device_list,
														SANE_Bool local_only )
{
	int             i;
	Plustek_Device *dev;

	DBG(_DBG_SANE_INIT, "sane_get_devices (%p, %ld)\n",
                                       (void *)device_list, (long) local_only);

	/* already called, so cleanup */
	if( devlist )
    	free( devlist );

	devlist = malloc((num_devices + 1) * sizeof (devlist[0]));
	if ( NULL == devlist )
    	return SANE_STATUS_NO_MEM;

	i = 0;
	for (dev = first_dev; i < num_devices; dev = dev->next)
    	devlist[i++] = &dev->sane;
	devlist[i++] = 0;

	*device_list = devlist;
	return SANE_STATUS_GOOD;
}

/** open the sane device
 */
SANE_Status sane_open( SANE_String_Const devicename, SANE_Handle* handle )
{
	SANE_Status      status;
	Plustek_Device  *dev;
	Plustek_Scanner *s;
    CnfDef           config;

	DBG( _DBG_SANE_INIT, "sane_open - %s\n", devicename );

	if( devicename[0] ) {
    	for( dev = first_dev; dev; dev = dev->next ) {
			if( strcmp( dev->sane.name, devicename ) == 0 )
				break;
        }

		if( !dev ) {

			memset( &config, 0, sizeof(CnfDef));
			
			status = attach( devicename, &config, &dev );
			if( SANE_STATUS_GOOD != status )
				return status;
		}
	} else {
		/* empty devicename -> use first device */
		dev = first_dev;
	}

	if( !dev )
    	return SANE_STATUS_INVAL;

	s = malloc (sizeof (*s));
	if( NULL == s )
    	return SANE_STATUS_NO_MEM;

	memset(s, 0, sizeof (*s));
	s->pipe     = -1;
	s->hw       = dev;
	s->scanning = SANE_FALSE;

	init_options(s);

	/* insert newly opened handle into list of open handles: */
	s->next      = first_handle;
	first_handle = s;

	*handle = s;
	
	return SANE_STATUS_GOOD;
}

/**
 */
void sane_close (SANE_Handle handle)
{
	Plustek_Scanner *prev, *s;

	DBG( _DBG_SANE_INIT, "sane_close\n" );

	/* remove handle from list of open handles: */
	prev = 0;

	for( s = first_handle; s; s = s->next ) {
		if( s == handle )
			break;
		prev = s;
	}

	if (!s) {
    	DBG( _DBG_ERROR, "close: invalid handle %p\n", handle);
		return;		
	}

	close_pipe( s );

	if( NULL != s->buf )
		free(s->buf);

	drvclose( s->hw );

	if (prev)
    	prev->next = s->next;
	else
    	first_handle = s->next;

	free(s);
}

/** goes through a string list and returns the start-address of the string
 * that has been found, or NULL on error
 */
static const SANE_String_Const *search_string_list(
                            const SANE_String_Const *list, SANE_String value )
{
	while( *list != NULL && strcmp(value, *list) != 0 )
		++list;

	if( *list == NULL )
		return NULL;

	return list;
}

/** return or set the parameter values, also do some checks
 */
SANE_Status sane_control_option( SANE_Handle handle, SANE_Int option,
							     SANE_Action action, void *value,
							     SANE_Int * info)
{
	Plustek_Scanner         *s = (Plustek_Scanner *)handle;
	SANE_Status              status;
	const SANE_String_Const *optval;
	pModeParam               mp;
	int                      scanmode, idx;

	if ( s->scanning )
		return SANE_STATUS_DEVICE_BUSY;

	if((option < 0) || (option >= NUM_OPTIONS))
    	return SANE_STATUS_INVAL;

	if( NULL != info )
		*info = 0;

	switch( action ) {

		case SANE_ACTION_GET_VALUE:
			switch (option) {
			case OPT_PREVIEW:
			case OPT_NUM_OPTS:
			case OPT_RESOLUTION:
			case OPT_TL_X:
			case OPT_TL_Y:
			case OPT_BR_X:
			case OPT_BR_Y:
			case OPT_CUSTOM_GAMMA:
			  *(SANE_Word *)value = s->val[option].w;
			  break;

			case OPT_CONTRAST:
			case OPT_BRIGHTNESS:
				*(SANE_Word *)value =
								(s->val[option].w << SANE_FIXED_SCALE_SHIFT);
				break;

			case OPT_MODE:
			case OPT_EXT_MODE:
				strcpy ((char *) value,
					  s->opt[option].constraint.string_list[s->val[option].w]);
				break;
	
	  		/* word array options: */
	  		case OPT_GAMMA_VECTOR:
			case OPT_GAMMA_VECTOR_R:
			case OPT_GAMMA_VECTOR_G:
			case OPT_GAMMA_VECTOR_B:
				memcpy( value, s->val[option].wa, s->opt[option].size );
				break;
								
			default:
				return SANE_STATUS_INVAL;
		}
		break;

    	case SANE_ACTION_SET_VALUE:
        	status = sanei_constrain_value( s->opt + option, value, info );
		    if( SANE_STATUS_GOOD != status )
			    return status;

    		optval = NULL;
	    	if( SANE_CONSTRAINT_STRING_LIST == s->opt[option].constraint_type ) {

		    	optval = search_string_list( s->opt[option].constraint.string_list,
								         (char *) value);
    			if( NULL == optval )
	        		return SANE_STATUS_INVAL;
		    }

          	switch (option) {

	    		case OPT_RESOLUTION: {
		    	    int n;
	    	    	int min_d = s->hw->res_list[s->hw->res_list_size - 1];
			        int v     = *(SANE_Word *)value;
    	    		int best  = v;

	    		    for( n = 0; n < s->hw->res_list_size; n++ ) {
		    			int d = abs(v - s->hw->res_list[n]);

					    if( d < min_d ) {
				    	    min_d = d;
				    	    best  = s->hw->res_list[n];
    					}
	    			}

	        		s->val[option].w = (SANE_Word)best;

                    if( v != best )
                        *(SANE_Word *)value = best;

	    			if( NULL != info ) {
		    			if( v != best )	
                            *info |= SANE_INFO_INEXACT;
				    	*info |= SANE_INFO_RELOAD_PARAMS;
         		  	}
	    		    break;

		      	}

				case OPT_PREVIEW:
    			case OPT_TL_X:
	    		case OPT_TL_Y:
		    	case OPT_BR_X:
			    case OPT_BR_Y:
    				s->val[option].w = *(SANE_Word *)value;
	    			if( NULL != info )
    					*info |= SANE_INFO_RELOAD_PARAMS;
	    			break;
				
				case OPT_CUSTOM_GAMMA:
    				s->val[option].w = *(SANE_Word *)value;
	    			if( NULL != info )
    					*info |= SANE_INFO_RELOAD_PARAMS | SANE_INFO_RELOAD_OPTIONS;

					mp       = getModeList( s );
					scanmode = mp[s->val[OPT_MODE].w].scanmode;

				    s->opt[OPT_GAMMA_VECTOR].cap   |= SANE_CAP_INACTIVE;
				    s->opt[OPT_GAMMA_VECTOR_R].cap |= SANE_CAP_INACTIVE;
				    s->opt[OPT_GAMMA_VECTOR_G].cap |= SANE_CAP_INACTIVE;
				    s->opt[OPT_GAMMA_VECTOR_B].cap |= SANE_CAP_INACTIVE;
					    					    					
    				if( SANE_TRUE == s->val[option].w ) {
    				
    					if((scanmode == COLOR_256GRAY) ||
						   (scanmode == COLOR_GRAY16)) {
						    s->opt[OPT_GAMMA_VECTOR].cap &= ~SANE_CAP_INACTIVE;
						} else {
						    s->opt[OPT_GAMMA_VECTOR_R].cap &= ~SANE_CAP_INACTIVE;
						    s->opt[OPT_GAMMA_VECTOR_G].cap &= ~SANE_CAP_INACTIVE;
						    s->opt[OPT_GAMMA_VECTOR_B].cap &= ~SANE_CAP_INACTIVE;
						}		
										
    				} else {
	
						initGammaSettings( s );
    				
    					if((scanmode == COLOR_256GRAY) ||
						   (scanmode == COLOR_GRAY16)) {
						    s->opt[OPT_GAMMA_VECTOR].cap |= SANE_CAP_INACTIVE;
						} else {						
						    s->opt[OPT_GAMMA_VECTOR_R].cap |= SANE_CAP_INACTIVE;
						    s->opt[OPT_GAMMA_VECTOR_G].cap |= SANE_CAP_INACTIVE;
						    s->opt[OPT_GAMMA_VECTOR_B].cap |= SANE_CAP_INACTIVE;
						}						
    				}
	    			break;

		    	case OPT_CONTRAST:
			    case OPT_BRIGHTNESS:
        			s->val[option].w =
							((*(SANE_Word *)value) >> SANE_FIXED_SCALE_SHIFT);
	    			break;

		    	case OPT_MODE: 
                    idx = (optval - mode_usb_list);
					mp  = getModeList( s );
					
					s->opt[OPT_CONTRAST].cap     &= ~SANE_CAP_INACTIVE;
					s->opt[OPT_CUSTOM_GAMMA].cap &= ~SANE_CAP_INACTIVE;

	    			if( mp[idx].scanmode == COLOR_BW ) {
			    		s->opt[OPT_CONTRAST].cap     |= SANE_CAP_INACTIVE;
			    		s->opt[OPT_CUSTOM_GAMMA].cap |= SANE_CAP_INACTIVE;
			    	}	
			    	
			    	s->opt[OPT_GAMMA_VECTOR].cap   |= SANE_CAP_INACTIVE;
			    	s->opt[OPT_GAMMA_VECTOR_R].cap |= SANE_CAP_INACTIVE;
			    	s->opt[OPT_GAMMA_VECTOR_G].cap |= SANE_CAP_INACTIVE;
			    	s->opt[OPT_GAMMA_VECTOR_B].cap |= SANE_CAP_INACTIVE;
					
					if( s->val[OPT_CUSTOM_GAMMA].w &&
			    		!(s->opt[OPT_CUSTOM_GAMMA].cap & SANE_CAP_INACTIVE)) {
			    		
    					if((mp[idx].scanmode == COLOR_256GRAY) ||
						   (mp[idx].scanmode == COLOR_GRAY16)) {
						    s->opt[OPT_GAMMA_VECTOR].cap   &= ~SANE_CAP_INACTIVE;
						} else {
					    	s->opt[OPT_GAMMA_VECTOR_R].cap &= ~SANE_CAP_INACTIVE;
					    	s->opt[OPT_GAMMA_VECTOR_G].cap &= ~SANE_CAP_INACTIVE;
					    	s->opt[OPT_GAMMA_VECTOR_B].cap &= ~SANE_CAP_INACTIVE;
						}
					}

			    	if( NULL != info )
    					*info |= SANE_INFO_RELOAD_OPTIONS | SANE_INFO_RELOAD_PARAMS;

			    	s->val[option].w = optval - s->opt[option].constraint.string_list;
				    break;

    			case OPT_EXT_MODE: {
	    			s->val[option].w = optval - s->opt[option].constraint.string_list;

		    		/*
			    	 * change the area and mode_list when changing the source
				     */
    				if( s->val[option].w == 0 ) {

	    				s->hw->dpi_range.min = _DEF_DPI;

		    			s->hw->x_range.max = SANE_FIX(s->hw->max_x);
			    		s->hw->y_range.max = SANE_FIX(s->hw->max_y);
				    	s->val[OPT_TL_X].w = SANE_FIX(_DEFAULT_TLX);
					    s->val[OPT_TL_Y].w = SANE_FIX(_DEFAULT_TLY);
   	    				s->val[OPT_BR_X].w = SANE_FIX(_DEFAULT_BRX);
    					s->val[OPT_BR_Y].w = SANE_FIX(_DEFAULT_BRY);

					    s->opt[OPT_MODE].constraint.string_list = mode_usb_list;
	    				s->val[OPT_MODE].w = COLOR_TRUE24;

				    } else {

					    s->hw->dpi_range.min = _TPAMinDpi;

    					if( s->val[option].w == 1 ) {
        					s->hw->x_range.max = SANE_FIX(_TP_X);
		    				s->hw->y_range.max = SANE_FIX(_TP_Y);
			    			s->val[OPT_TL_X].w = SANE_FIX(_DEFAULT_TP_TLX);
				    		s->val[OPT_TL_Y].w = SANE_FIX(_DEFAULT_TP_TLY);
   					    	s->val[OPT_BR_X].w = SANE_FIX(_DEFAULT_TP_BRX);
						    s->val[OPT_BR_Y].w = SANE_FIX(_DEFAULT_TP_BRY);

    					} else {
        					s->hw->x_range.max = SANE_FIX(_NEG_X);
			    			s->hw->y_range.max = SANE_FIX(_NEG_Y);
		    				s->val[OPT_TL_X].w = SANE_FIX(_DEFAULT_NEG_TLX);
				    		s->val[OPT_TL_Y].w = SANE_FIX(_DEFAULT_NEG_TLY);
   					    	s->val[OPT_BR_X].w = SANE_FIX(_DEFAULT_NEG_BRX);
						    s->val[OPT_BR_Y].w = SANE_FIX(_DEFAULT_NEG_BRY);
    					}
	    				s->opt[OPT_MODE].constraint.string_list =
											&mode_usb_list[_TPAModeSupportMin];
						s->val[OPT_MODE].w = 0;		/* COLOR_24 is the default */
        			}

				    s->opt[OPT_CONTRAST].cap &= ~SANE_CAP_INACTIVE;

    				if( NULL != info )
	    				*info |= SANE_INFO_RELOAD_OPTIONS | SANE_INFO_RELOAD_PARAMS;
		    		break;
	            }
				case OPT_GAMMA_VECTOR:
				case OPT_GAMMA_VECTOR_R:
				case OPT_GAMMA_VECTOR_G:
				case OPT_GAMMA_VECTOR_B:
					memcpy( s->val[option].wa, value, s->opt[option].size );
					checkGammaSettings(s);
	    			if( NULL != info )
		    			*info |= SANE_INFO_RELOAD_PARAMS;
					break;

			    default:
				    return SANE_STATUS_INVAL;
    		}
	    	break;
	    	

    	default:
        	return SANE_STATUS_INVAL;
	}

	return SANE_STATUS_GOOD;
}

/** according to the option number, return a pointer to a descriptor
 */
const SANE_Option_Descriptor *
   			 sane_get_option_descriptor( SANE_Handle handle, SANE_Int option )
{
	Plustek_Scanner *s = (Plustek_Scanner *)handle;

	if((option < 0) || (option >= NUM_OPTIONS))
		return NULL;

	return &(s->opt[option]);
}

/** return the current parameter settings
 */
SANE_Status sane_get_parameters( SANE_Handle handle, SANE_Parameters *params )
{
	int    			 ndpi;
	pModeParam  	 mp;
	Plustek_Scanner *s = (Plustek_Scanner *)handle;

	/* if we're calling from within, calc best guess
     * do the same, if sane_get_parameters() is called
     * by a frontend before sane_start() is called
     */
    if((NULL == params) || (s->scanning != SANE_TRUE)) {

		mp = getModeList( s );

		memset( &s->params, 0, sizeof (SANE_Parameters));

		ndpi = s->val[OPT_RESOLUTION].w;

	    s->params.pixels_per_line =	SANE_UNFIX(s->val[OPT_BR_X].w -
									  s->val[OPT_TL_X].w) / MM_PER_INCH * ndpi;

    	s->params.lines = SANE_UNFIX( s->val[OPT_BR_Y].w -
									  s->val[OPT_TL_Y].w) / MM_PER_INCH * ndpi;

		/* pixels_per_line seems to be 8 * n.  */
		/* s->params.pixels_per_line = s->params.pixels_per_line & ~7; debug only */

	    s->params.last_frame = SANE_TRUE;
    	s->params.depth      = mp[s->val[OPT_MODE].w].depth;

		if( mp[s->val[OPT_MODE].w].color ) {
			s->params.format = SANE_FRAME_RGB;
			s->params.bytes_per_line = 3 * s->params.pixels_per_line;
		} else {
			s->params.format = SANE_FRAME_GRAY;
			if (s->params.depth == 1)
				s->params.bytes_per_line = (s->params.pixels_per_line + 7) / 8;
			else
				s->params.bytes_per_line = s->params.pixels_per_line *
														   s->params.depth / 8;
		}

        /* if sane_get_parameters() was called before sane_start() */
	    /* pass new values to the caller                           */
    	if ((NULL != params) &&	(s->scanning != SANE_TRUE))
	    	*params = s->params;
	} else
		*params = s->params;

	return SANE_STATUS_GOOD;
}

/** initiate the scan process
 */
SANE_Status sane_start( SANE_Handle handle )
{
	Plustek_Scanner *s = (Plustek_Scanner *)handle;
	pPlustek_Device  dev;
	pModeParam       mp;

	int         result;
	int         ndpi;
	int         left, top;
	int         width, height;
	int         scanmode;
	int         fds[2];
	double      dpi_x, dpi_y;
	CropInfo    crop;
	ScanInfo    sinfo;
	SANE_Status status;
	SANE_Word   tmp;

	DBG( _DBG_SANE_INIT, "sane_start\n" );

	if( s->scanning ) {
		return SANE_STATUS_DEVICE_BUSY;
	}

	status = sane_get_parameters (handle, NULL);
	if (status != SANE_STATUS_GOOD) {
		DBG( _DBG_ERROR, "sane_get_parameters failed\n" );
		return status;
	}

	dev = s->hw;

	/*
	 * open the driver and get some information about the scanner
	 */
	dev->fd = drvopen( dev );
	if( dev->fd < 0 ) {
		DBG( _DBG_ERROR,"sane_start: open failed: %d\n", errno );

		if( errno == EBUSY )
			return SANE_STATUS_DEVICE_BUSY;

		return SANE_STATUS_IO_ERROR;
	}

	result = dev->getCaps( dev );
	if( result < 0 ) {
		DBG( _DBG_ERROR, "dev->getCaps() failed(%d)\n", result);
		dev->close( dev );
		return SANE_STATUS_IO_ERROR;
    }
	
	/* All ready to go.  Set image def and see what the scanner
	 * says for crop info.
	 */
	ndpi = s->val[OPT_RESOLUTION].w;

    /* exchange the values as we can't deal with negative heights and so on...*/
    tmp = s->val[OPT_TL_X].w;
    if( tmp > s->val[OPT_BR_X].w ) {
		DBG( _DBG_INFO, "exchanging BR-X - TL-X\n" );
        s->val[OPT_TL_X].w = s->val[OPT_BR_X].w;
        s->val[OPT_BR_X].w = tmp;
    }

    tmp = s->val[OPT_TL_Y].w;
    if( tmp > s->val[OPT_BR_Y].w ) {
		DBG( _DBG_INFO, "exchanging BR-Y - TL-Y\n" );
        s->val[OPT_TL_Y].w = s->val[OPT_BR_Y].w;
        s->val[OPT_BR_Y].w = tmp;
    }

	/* position and extent are always relative to 300 dpi */
	dpi_x = (double)dev->usbDev.Caps.OpticDpi.x; 
	dpi_y = (double)dev->usbDev.Caps.OpticDpi.x * 2;
	
	left   = (int)(SANE_UNFIX (s->val[OPT_TL_X].w)*dpi_x/
												(MM_PER_INCH*(dpi_x/300.0)));
	top    = (int)(SANE_UNFIX (s->val[OPT_TL_Y].w)*dpi_y/
												(MM_PER_INCH*(dpi_y/300.0)));
	width  = (int)(SANE_UNFIX (s->val[OPT_BR_X].w - s->val[OPT_TL_X].w) *
										dpi_x / (MM_PER_INCH *(dpi_x/300.0)));
	height = (int)(SANE_UNFIX (s->val[OPT_BR_Y].w - s->val[OPT_TL_Y].w) *
										dpi_y / (MM_PER_INCH *(dpi_y/300.0)));
	/*
	 * adjust mode list according to the model we use and the
	 * source we have
	 */
	mp = getModeList( s );

	scanmode = mp[s->val[OPT_MODE].w].scanmode;
	DBG( _DBG_INFO, "scanmode = %u\n", scanmode );

	/* clear it out just in case */
	memset (&crop, 0, sizeof(crop));
	crop.ImgDef.xyDpi.x   = ndpi;
	crop.ImgDef.xyDpi.y   = ndpi;
	crop.ImgDef.crArea.x  = left;  /* offset from left edge to area you want to scan */
	crop.ImgDef.crArea.y  = top;  	/* offset from top edge to area you want to scan  */
	crop.ImgDef.crArea.cx = width; /* always relative to 300 dpi */
	crop.ImgDef.crArea.cy = height;
	crop.ImgDef.wDataType = scanmode;
	crop.ImgDef.dwFlag    = SCANDEF_QualityScan;

	switch( s->val[OPT_EXT_MODE].w ) {
		case 1: crop.ImgDef.dwFlag |= SCANDEF_Transparency; break;
		case 2: crop.ImgDef.dwFlag |= SCANDEF_Negative;     break;
		default: break;
	}

	result = dev->getCropInfo( dev, &crop );
	if( result < 0 ) {
	    DBG( _DBG_ERROR, "dev->getCropInfo() failed(%d)\n", result );
		dev->close( dev );
    	return SANE_STATUS_IO_ERROR;
    }

	/* DataInf.dwAppPixelsPerLine = crop.dwPixelsPerLine;  */
	s->params.pixels_per_line = crop.dwPixelsPerLine;
	s->params.bytes_per_line  = crop.dwBytesPerLine;
	s->params.lines 		  = crop.dwLinesPerArea;

	/* build a SCANINFO block and get ready to scan it */
	crop.ImgDef.dwFlag |= SCANDEF_QualityScan;

	/* remove that for preview scans */
	if( s->val[OPT_PREVIEW].w )
		crop.ImgDef.dwFlag &= (~SCANDEF_QualityScan);

    /* set adjustments for brightness and contrast */
	sinfo.siBrightness = s->val[OPT_BRIGHTNESS].w;
	sinfo.siContrast   = s->val[OPT_CONTRAST].w;

    memcpy( &sinfo.ImgDef, &crop.ImgDef, sizeof(ImgDef));
	
	DBG( _DBG_SANE_INIT, "brightness %i, contrast %i\n",
						sinfo.siBrightness, sinfo.siContrast );

	result = dev->setScanEnv( dev, &sinfo );
	if( result < 0 ) {
		DBG( _DBG_ERROR, "dev->setEnv() failed(%d)\n", result );
		dev->close( dev );
		return SANE_STATUS_IO_ERROR;
    }

    /* download gamma correction tables... */
	if( scanmode <= COLOR_GRAY16 ) {
	   	dev->setMap( dev, s->gamma_table[0], s->gamma_length, _MAP_MASTER);
	} else {
	   	dev->setMap( dev, s->gamma_table[1], s->gamma_length, _MAP_RED   );
   		dev->setMap( dev, s->gamma_table[2], s->gamma_length, _MAP_GREEN );
   		dev->setMap( dev, s->gamma_table[3], s->gamma_length, _MAP_BLUE  );
    }

	result = dev->startScan( dev );
	if( result < 0 ) {
		DBG( _DBG_ERROR, "dev->startScan() failed(%d)\n", result );
		dev->close( dev );
		return SANE_STATUS_IO_ERROR;
    }

	DBG( _DBG_SANE_INIT, "dwflag = 0x%lx dwBytesPerLine = %ld \n",
						dev->scanning.dwFlag, dev->scanning.dwBytesLine );

	s->buf = realloc( s->buf, (s->params.lines) * s->params.bytes_per_line );
	if( NULL == s->buf ) {
		DBG( _DBG_ERROR, "realloc failed\n" );
		dev->close( dev );
		return SANE_STATUS_NO_MEM;
	}

	s->scanning = SANE_TRUE;

	tsecs = (unsigned long)time(NULL);
	DBG( _DBG_INFO, "TIME START\n" );

	/*
	 * everything prepared, so start the child process and a pipe to communicate
	 * pipe --> fds[0]=read-fd, fds[1]=write-fd
	 */
	if( pipe(fds) < 0 ) {
		DBG( _DBG_ERROR, "ERROR: could not create pipe\n" );
	    s->scanning = SANE_FALSE;
		dev->close( dev );
		return SANE_STATUS_IO_ERROR;
	}

	/* create reader routine as new process */
	s->bytes_read = 0;
  	s->reader_pid = fork();			

	cancelRead = SANE_FALSE;
	
	if( s->reader_pid < 0 ) {
		DBG( _DBG_ERROR, "ERROR: could not create child process\n" );
	    s->scanning = SANE_FALSE;
		dev->close( dev );
		return SANE_STATUS_IO_ERROR;
	}

	/* reader_pid = 0 ===> child process */		
	if( 0 == s->reader_pid ) {									

		sigset_t 		 ignore_set;
		struct SIGACTION act;

		DBG( _DBG_SANE_INIT, "reader process...\n" );

		close(fds[0]);

		sigfillset ( &ignore_set );
		sigdelset  ( &ignore_set, SIGTERM );
		sigprocmask( SIG_SETMASK, &ignore_set, 0 );

		memset   ( &act, 0, sizeof (act));
		sigaction( SIGTERM, &act, 0 );

		status = reader_process( s, fds[1] );

		DBG( _DBG_SANE_INIT, "reader process done, status = %i\n", status );

		/* don't use exit() since that would run the atexit() handlers */
		_exit( status );
	}

	signal( SIGCHLD, sig_chldhandler );

	close(fds[1]);
	s->pipe = fds[0];

	DBG( _DBG_SANE_INIT, "sane_start done\n" );

	return SANE_STATUS_GOOD;
}

/** function to read the data from our child process
 */
SANE_Status sane_read( SANE_Handle handle, SANE_Byte *data,
									   SANE_Int max_length, SANE_Int *length )
{
	Plustek_Scanner *s = (Plustek_Scanner*)handle;
	ssize_t 		 nread;

	*length = 0;

	/* here we read all data from the driver... */
	nread = read( s->pipe, data, max_length );
	DBG( _DBG_READ, "sane_read - read %ld bytes\n", (long)nread );
	if (!(s->scanning)) {
		return do_cancel( s, SANE_TRUE );
	}

	if( nread < 0 ) {

		if( EAGAIN == errno ) {

            /* if we already had red the picture, so it's okay and stop */
			if( s->bytes_read ==
				(unsigned long)(s->params.lines * s->params.bytes_per_line)) {
				waitpid( s->reader_pid, 0, 0 );
				s->reader_pid = -1;
				drvclose( s->hw );
				return close_pipe(s);
			}

            /* else force the frontend to try again*/
			return SANE_STATUS_GOOD;

		} else {
			DBG( _DBG_ERROR, "ERROR: errno=%d\n", errno );
			do_cancel( s, SANE_TRUE );
			return SANE_STATUS_IO_ERROR;
		}
	}

	*length        = nread;
	s->bytes_read += nread;

    /* nothing red means that we're finished OR we had a problem...*/
	if( 0 == nread ) {

		drvclose( s->hw );
        getReaderProcessExitCode( s );

        if( SANE_STATUS_GOOD != s->exit_code ) {
            close_pipe(s);
      		return s->exit_code;
        }
		return close_pipe(s);
	}

	return SANE_STATUS_GOOD;
}

/** cancel the scanning process
 */
void sane_cancel (SANE_Handle handle)
{
	Plustek_Scanner *s = (Plustek_Scanner *)handle;

	DBG( _DBG_SANE_INIT, "sane_cancel\n" );

	if( s->scanning )
		do_cancel( s, SANE_FALSE );
}

/** set the pipe to blocking/non blocking mode
 */
SANE_Status sane_set_io_mode (SANE_Handle handle, SANE_Bool non_blocking)
{
	Plustek_Scanner *s = (Plustek_Scanner *)handle;

	DBG( _DBG_SANE_INIT, "sane_set_io_mode: non_blocking=%d\n",non_blocking );

	if ( !s->scanning ) {
		DBG( _DBG_ERROR, "ERROR: not scanning !\n" );
		return SANE_STATUS_INVAL;
	}

	if( -1 == s->pipe ) {
		DBG( _DBG_ERROR, "ERROR: not supported !\n" );
		return SANE_STATUS_UNSUPPORTED;
	}
	
	if( fcntl (s->pipe, F_SETFL, non_blocking ? O_NONBLOCK : 0) < 0) {
		DBG( _DBG_ERROR, "ERROR: can<61>t set to non-blocking mode !\n" );
		return SANE_STATUS_IO_ERROR;
	}

	DBG( _DBG_SANE_INIT, "sane_set_io_mode done\n" );
	return SANE_STATUS_GOOD;
}

/** return the descriptor if available
 */
SANE_Status sane_get_select_fd( SANE_Handle handle, SANE_Int * fd )
{
	Plustek_Scanner *s = (Plustek_Scanner *)handle;

	DBG( _DBG_SANE_INIT, "sane_get_select_fd\n" );

	if( !s->scanning ) {
		DBG( _DBG_ERROR, "ERROR: not scanning !\n" );
		return SANE_STATUS_INVAL;
	}

	*fd = s->pipe;

	DBG( _DBG_SANE_INIT, "sane_get_select_fd done\n" );
	return SANE_STATUS_GOOD;
}

/* END PLUSTEK.C ............................................................*/