/* sane - Scanner Access Now Easy.
   Copyright (C) Marian Eichholz 2001
   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, see <https://www.gnu.org/licenses/>.

   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.
*/

/* ======================================================================

Userspace scan tool for the Microtek 3600 scanner

grayscale scan routine

(C) Marian Eichholz 2001

====================================================================== */

#include "sm3600-scantool.h"

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

DoScanGray()

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

#define LINE_THRESHOLD   0x800

static unsigned char uchRegs075[]={
   /*R_SPOS*/ 0xFC, /*R_SPOSH*/ 0x00, /*0x03*/ 0x20,
   /*R_SWID*/ 0xB0, /*R_SWIDH*/ 0x04, /*R_STPS*/ 0x06,
   /*R_STPSH*/ 0x00, /*0x08*/ 0x00, /*0x09*/ 0x3F,
   /*R_LEN*/ 0x28, /*R_LENH*/ 0x07, /*0x0C*/ 0x6D,
   /*0x0D*/ 0x70, /*0x0E*/ 0x69, /*0x0F*/ 0xD0,
   /*0x10*/ 0x00, /*0x11*/ 0x00, /*0x12*/ 0x40,
   /*0x13*/ 0x15, /*0x14*/ 0x80, /*0x15*/ 0x2A,
   /*0x16*/ 0xC0, /*0x17*/ 0x40, /*0x18*/ 0xC0,
   /*0x19*/ 0x40, /*0x1A*/ 0xFF, /*0x1B*/ 0x01,
   /*0x1C*/ 0x88, /*0x1D*/ 0x40, /*0x1E*/ 0x4C,
   /*0x1F*/ 0x50, /*0x20*/ 0x00, /*0x21*/ 0x0C,
   /*0x22*/ 0x21, /*0x23*/ 0xF0, /*0x24*/ 0x40,
   /*0x25*/ 0x00, /*0x26*/ 0x0A, /*0x27*/ 0xF0,
   /*0x28*/ 0x00, /*0x29*/ 0x00, /*0x2A*/ 0x4E,
   /*0x2B*/ 0xF0, /*0x2C*/ 0x00, /*0x2D*/ 0x00,
   /*0x2E*/ 0x4E, /*R_CCAL*/ 0x80, /*R_CCAL2*/ 0x80,
   /*R_CCAL3*/ 0x80, /*0x32*/ 0xC9, /*0x33*/ 0x20,
   /*0x34*/ 0x83, /*0x35*/ 0x29, /*0x36*/ 0x00,
   /*0x37*/ 0x00, /*0x38*/ 0x00, /*0x39*/ 0x00,
   /*0x3A*/ 0x00, /*0x3B*/ 0x00, /*0x3C*/ 0xFF,
   /*0x3D*/ 0x0F, /*0x3E*/ 0x00, /*0x3F*/ 0x00,
   /*0x40*/ 0x01, /*0x41*/ 0x00, /*R_CSTAT*/ 0x00,
   /*0x43*/ 0x03, /*R_LMP*/ 0x01, /*0x45*/ 0x00,
   /*R_CTL*/ 0x39, /*0x47*/ 0xC0, /*0x48*/ 0x40,
   /*0x49*/ 0x9E, /*0x4A*/ 0x8C };

static unsigned char uchRegs100[]={
   /*R_SPOS*/ 0xFC, /*R_SPOSH*/ 0x00, /*0x03*/ 0x20,
   /*R_SWID*/ 0xB0, /*R_SWIDH*/ 0x04, /*R_STPS*/ 0x06,
   /*R_STPSH*/ 0x00, /*0x08*/ 0x00, /*0x09*/ 0x3F,
   /*R_LEN*/ 0x34, /*R_LENH*/ 0x07, /*0x0C*/ 0x6D,
   /*0x0D*/ 0x70, /*0x0E*/ 0x69, /*0x0F*/ 0xD0,
   /*0x10*/ 0x00, /*0x11*/ 0x00, /*0x12*/ 0x42,
   /*0x13*/ 0x15, /*0x14*/ 0x84, /*0x15*/ 0x2A,
   /*0x16*/ 0xC2, /*0x17*/ 0x40, /*0x18*/ 0xC2,
   /*0x19*/ 0x40, /*0x1A*/ 0xFF, /*0x1B*/ 0x01,
   /*0x1C*/ 0x88, /*0x1D*/ 0x40, /*0x1E*/ 0x4C,
   /*0x1F*/ 0x50, /*0x20*/ 0x00, /*0x21*/ 0x0C,
   /*0x22*/ 0x21, /*0x23*/ 0xF0, /*0x24*/ 0x40,
   /*0x25*/ 0x00, /*0x26*/ 0x0A, /*0x27*/ 0xF0,
   /*0x28*/ 0x00, /*0x29*/ 0x00, /*0x2A*/ 0x4E,
   /*0x2B*/ 0xF0, /*0x2C*/ 0x00, /*0x2D*/ 0x00,
   /*0x2E*/ 0x4E, /*R_CCAL*/ 0x80, /*R_CCAL2*/ 0x80,
   /*R_CCAL3*/ 0x80, /*0x32*/ 0xC9, /*0x33*/ 0x20,
   /*0x34*/ 0x63, /*0x35*/ 0x29, /*0x36*/ 0x00,
   /*0x37*/ 0x00, /*0x38*/ 0x00, /*0x39*/ 0x00,
   /*0x3A*/ 0x00, /*0x3B*/ 0x00, /*0x3C*/ 0xFF,
   /*0x3D*/ 0x0F, /*0x3E*/ 0x00, /*0x3F*/ 0x00,
   /*0x40*/ 0x01, /*0x41*/ 0x00, /*R_CSTAT*/ 0x80,
   /*0x43*/ 0x03, /*R_LMP*/ 0x01, /*0x45*/ 0x00,
   /*R_CTL*/ 0x39, /*0x47*/ 0xC2, /*0x48*/ 0x40,
   /*0x49*/ 0x9E, /*0x4A*/ 0x8C };

static unsigned char uchRegs200[]={
   /*R_SPOS*/ 0xFC, /*R_SPOSH*/ 0x00, /*0x03*/ 0x24,
   /*R_SWID*/ 0xB0, /*R_SWIDH*/ 0x04, /*R_STPS*/ 0x06,
   /*R_STPSH*/ 0x00, /*0x08*/ 0x00, /*0x09*/ 0x3F,
   /*R_LEN*/ 0x22, /*R_LENH*/ 0x07, /*0x0C*/ 0x6D,
   /*0x0D*/ 0x70, /*0x0E*/ 0x69, /*0x0F*/ 0xD0,
   /*0x10*/ 0x00, /*0x11*/ 0x00, /*0x12*/ 0x42,
   /*0x13*/ 0x15, /*0x14*/ 0x42, /*0x15*/ 0x15,
   /*0x16*/ 0x42, /*0x17*/ 0x15, /*0x18*/ 0x42,
   /*0x19*/ 0x15, /*0x1A*/ 0x07, /*0x1B*/ 0x00,
   /*0x1C*/ 0x08, /*0x1D*/ 0x12, /*0x1E*/ 0x4C,
   /*0x1F*/ 0x50, /*0x20*/ 0x00, /*0x21*/ 0x0C,
   /*0x22*/ 0x21, /*0x23*/ 0xF0, /*0x24*/ 0x40,
   /*0x25*/ 0x00, /*0x26*/ 0x0A, /*0x27*/ 0xF0,
   /*0x28*/ 0x00, /*0x29*/ 0x00, /*0x2A*/ 0x4E,
   /*0x2B*/ 0xF0, /*0x2C*/ 0x00, /*0x2D*/ 0x00,
   /*0x2E*/ 0x4E, /*R_CCAL*/ 0x80, /*R_CCAL2*/ 0x80,
   /*R_CCAL3*/ 0x80, /*0x32*/ 0xC9, /*0x33*/ 0x20,
   /*0x34*/ 0x43, /*0x35*/ 0x29, /*0x36*/ 0x00,
   /*0x37*/ 0x00, /*0x38*/ 0x00, /*0x39*/ 0x00,
   /*0x3A*/ 0x00, /*0x3B*/ 0x00, /*0x3C*/ 0xFF,
   /*0x3D*/ 0x0F, /*0x3E*/ 0x00, /*0x3F*/ 0x00,
   /*0x40*/ 0x01, /*0x41*/ 0x00, /*R_CSTAT*/ 0x80,
   /*0x43*/ 0x03, /*R_LMP*/ 0x01, /*0x45*/ 0x00,
   /*R_CTL*/ 0x39, /*0x47*/ 0x42, /*0x48*/ 0x15,
   /*0x49*/ 0x9E, /*0x4A*/ 0x8C };

static unsigned char uchRegs300[]={
   /*R_SPOS*/ 0xFC, /*R_SPOSH*/ 0x00, /*0x03*/ 0x2A,
   /*R_SWID*/ 0xB0, /*R_SWIDH*/ 0x04, /*R_STPS*/ 0x06,
   /*R_STPSH*/ 0x00, /*0x08*/ 0x00, /*0x09*/ 0x2A,
   /*R_LEN*/ 0x16, /*R_LENH*/ 0x07, /*0x0C*/ 0x6D,
   /*0x0D*/ 0x70, /*0x0E*/ 0x69, /*0x0F*/ 0xD0,
   /*0x10*/ 0x00, /*0x11*/ 0x00, /*0x12*/ 0x40,
   /*0x13*/ 0x15, /*0x14*/ 0x40, /*0x15*/ 0x15,
   /*0x16*/ 0x40, /*0x17*/ 0x15, /*0x18*/ 0x40,
   /*0x19*/ 0x15, /*0x1A*/ 0x07, /*0x1B*/ 0x00,
   /*0x1C*/ 0x08, /*0x1D*/ 0x12, /*0x1E*/ 0x4C,
   /*0x1F*/ 0x50, /*0x20*/ 0x00, /*0x21*/ 0x0C,
   /*0x22*/ 0x21, /*0x23*/ 0xF0, /*0x24*/ 0x40,
   /*0x25*/ 0x00, /*0x26*/ 0x0A, /*0x27*/ 0xF0,
   /*0x28*/ 0x00, /*0x29*/ 0x00, /*0x2A*/ 0x4E,
   /*0x2B*/ 0xF0, /*0x2C*/ 0x00, /*0x2D*/ 0x00,
   /*0x2E*/ 0x4E, /*R_CCAL*/ 0x80, /*R_CCAL2*/ 0x80,
   /*R_CCAL3*/ 0x80, /*0x32*/ 0xC9, /*0x33*/ 0x20,
   /*0x34*/ 0x03, /*0x35*/ 0x29, /*0x36*/ 0x00,
   /*0x37*/ 0x00, /*0x38*/ 0x00, /*0x39*/ 0x00,
   /*0x3A*/ 0x00, /*0x3B*/ 0x00, /*0x3C*/ 0xFF,
   /*0x3D*/ 0x0F, /*0x3E*/ 0x00, /*0x3F*/ 0x00,
   /*0x40*/ 0x01, /*0x41*/ 0x00, /*R_CSTAT*/ 0x80,
   /*0x43*/ 0x03, /*R_LMP*/ 0x01, /*0x45*/ 0x00,
   /*R_CTL*/ 0x39, /*0x47*/ 0x40, /*0x48*/ 0x15,
   /*0x49*/ 0x96, /*0x4A*/ 0x8C };

static unsigned char uchRegs600[]={
   /*R_SPOS*/ 0xFC, /*R_SPOSH*/ 0x00, /*0x03*/ 0x3F,
   /*R_SWID*/ 0xB0, /*R_SWIDH*/ 0x04, /*R_STPS*/ 0x06,
   /*R_STPSH*/ 0x00, /*0x08*/ 0x00, /*0x09*/ 0x3F,
   /*R_LEN*/ 0x16, /*R_LENH*/ 0x07, /*0x0C*/ 0x6D,
   /*0x0D*/ 0x70, /*0x0E*/ 0x69, /*0x0F*/ 0xD0,
   /*0x10*/ 0x00, /*0x11*/ 0x00, /*0x12*/ 0x42,
   /*0x13*/ 0x15, /*0x14*/ 0x42, /*0x15*/ 0x15,
   /*0x16*/ 0x42, /*0x17*/ 0x15, /*0x18*/ 0x42,
   /*0x19*/ 0x15, /*0x1A*/ 0x07, /*0x1B*/ 0x00,
   /*0x1C*/ 0x08, /*0x1D*/ 0x12, /*0x1E*/ 0x4C,
   /*0x1F*/ 0x50, /*0x20*/ 0x00, /*0x21*/ 0x0C,
   /*0x22*/ 0x21, /*0x23*/ 0xF0, /*0x24*/ 0x40,
   /*0x25*/ 0x00, /*0x26*/ 0x0A, /*0x27*/ 0xF0,
   /*0x28*/ 0x00, /*0x29*/ 0x00, /*0x2A*/ 0x4E,
   /*0x2B*/ 0xF0, /*0x2C*/ 0x00, /*0x2D*/ 0x00,
   /*0x2E*/ 0x4E, /*R_CCAL*/ 0x80, /*R_CCAL2*/ 0x80,
   /*R_CCAL3*/ 0x80, /*0x32*/ 0xC9, /*0x33*/ 0x20,
   /*0x34*/ 0x03, /*0x35*/ 0x29, /*0x36*/ 0x00,
   /*0x37*/ 0x00, /*0x38*/ 0x00, /*0x39*/ 0x00,
   /*0x3A*/ 0x00, /*0x3B*/ 0x00, /*0x3C*/ 0xFF,
   /*0x3D*/ 0x0F, /*0x3E*/ 0x00, /*0x3F*/ 0x00,
   /*0x40*/ 0x01, /*0x41*/ 0x00, /*R_CSTAT*/ 0x80,
   /*0x43*/ 0x03, /*R_LMP*/ 0x01, /*0x45*/ 0x00,
   /*R_CTL*/ 0x39, /*0x47*/ 0x42, /*0x48*/ 0x15,
   /*0x49*/ 0x96, /*0x4A*/ 0x8C };

/* ======================================================================

ReadNextGrayLine()

====================================================================== */

static TState ReadNextGrayLine(PTInstance this)
{
  int           iWrite;
  int           iDot;
  unsigned char chBits;
  int           iRead; /* read position in raw line */
  int           nInterpolator;

  iWrite=0;

  while (iWrite<this->state.cxMax) /* max 1 time in reality */
    {
      while (iWrite<this->state.cxMax &&
	     this->state.iBulkReadPos<this->state.cchBulk)
	this->state.ppchLines[0][iWrite++] += /* add! */
	  this->state.pchBuf[this->state.iBulkReadPos++]<<4;
      if (iWrite<this->state.cxMax) /* we need an additional chunk */
	{
	  if (this->state.bLastBulk)
	      return SANE_STATUS_EOF;
	  this->state.cchBulk=BulkReadBuffer(this,this->state.pchBuf,
					     USB_CHUNK_SIZE);
	  dprintf(DEBUG_SCAN,"bulk read: %d byte(s), line #%d\n",
		  this->state.cchBulk, this->state.iLine);
	  if (this->bWriteRaw)
	    fwrite(this->state.pchBuf,1,this->state.cchBulk,this->fhScan);
	  INST_ASSERT();
	  if (this->state.cchBulk!=USB_CHUNK_SIZE)
	    this->state.bLastBulk=true;
	  this->state.iBulkReadPos=0;
	}
    } /* while raw line buffer acquiring */
  this->state.iLine++;
  iDot=0; chBits=0; /* init pixelbuffer */
  for (nInterpolator=50, iWrite=0, iRead=0;
       iRead<this->state.cxMax;
       iRead++)
    {
      nInterpolator+=this->state.nFixAspect;
      if (nInterpolator<100) continue; /* res. reduction */
      nInterpolator-=100;
      if (iWrite>=this->state.cchLineOut) continue;
      /* dprintf(DEBUG_SCAN," i=%d",iTo); */
      if (this->mode==gray)
	  this->state.pchLineOut[iWrite++]=
	    this->state.ppchLines[0][iRead]>>4;
      else
	{
	  unsigned char chBit; /* 1=white */
	  if (this->mode==line)
	    chBit=(this->state.ppchLines[0][iRead]<LINE_THRESHOLD);
	  else
	    {
	      short nError=this->state.ppchLines[0][iRead];
	      /* printf("(%d)",nError); */
	      if (nError>=0xFF0)
		{
		  nError-=0xFF0;
		  chBit=0;
		}
	      else
		chBit=1;
	      /* since I sketched the Floyd-Steinberg
		 algorithm from heart, I have no idea, if
		 there is room for improvement in the
		 coefficients.  If You know, please drop
		 me a line (eichholz@computer.org, 1.4.2001) */
#define FASTDITHER
#ifdef FASTDITHER
	      this->state.ppchLines[0][iRead+1]+=(nError>>2); /* 8/16 */
	      this->state.ppchLines[1][iRead+1]+=(nError>>1);
	      this->state.ppchLines[1][iRead]  +=(nError>>2); /* 8/16 */
#else
	      this->state.ppchLines[0][iRead+1]+=(nError*5)>>4;
	      this->state.ppchLines[1][iRead+1]+=(nError*8)>>4;
	      this->state.ppchLines[1][iRead]  +=(nError*3)>>4;
#endif
	    }
	  chBits=(chBits<<1)|chBit;
	  iDot++;
	  if (iDot==8 && iWrite<this->state.cchLineOut)
	    {
	      this->state.pchLineOut[iWrite++]=chBits;
	      iDot=0; chBits=0;
	    }
	} /* gray pixel postprocessing */
    } /* line postprocessing */
  if (iDot && iWrite<this->state.cchLineOut)
    this->state.pchLineOut[iWrite++]=chBits;
  /* cycle the history lines and clear the preread buffer*/
  {
    short *p=this->state.ppchLines[0];
    this->state.ppchLines[0]=this->state.ppchLines[1];
    this->state.ppchLines[1]=p;
    memset(this->state.ppchLines[1],0,(this->state.cxMax+1)*sizeof(short));
  }
  return SANE_STATUS_GOOD;
}

/* ======================================================================

StartScanGray()

====================================================================== */

__SM3600EXPORT__
TState StartScanGray(TInstance *this)
{
  unsigned char  *puchRegs;
  int             i;
  if (this->state.bScanning)
    return SetError(this,SANE_STATUS_DEVICE_BUSY,"scan active");
  memset(&(this->state),0,sizeof(TScanState));
  this->state.ReadProc  =ReadNextGrayLine;
  puchRegs=NULL;
  switch (this->param.res)
  {
  case 75:  puchRegs=uchRegs075; break;
  case 100: puchRegs=uchRegs100; break;
  case 200: puchRegs=uchRegs200; break;
  case 300: puchRegs=uchRegs300; break;
  case 600: puchRegs=uchRegs600; break;
  }
  GetAreaSize(this);
  this->state.cyTotalPath = this->param.y/2;
  DoJog(this,this->state.cyTotalPath);
  INST_ASSERT();
  this->state.cyTotalPath += this->param.cy/2; /* for jogging back */

  /*
    regular scan is asynchronously, that is,
    the scanning is issued, and the driver does bulk reads,
    until there are no data left.
  */
  RegWriteArray(this,R_ALL, NUM_SCANREGS, puchRegs); INST_ASSERT();
  RegWrite(this,R_SPOS, 2,
	   this->param.x/2+this->calibration.xMargin); INST_ASSERT();
  RegWrite(this,R_SLEN, 2, this->state.cyWindow); INST_ASSERT();
  RegWrite(this,R_SWID, 2, this->state.cxWindow); INST_ASSERT();
  RegWrite(this,R_STPS, 2, 0); INST_ASSERT();

  /* upload gamma table */
  RegWrite(this,0x41,1,0x01); /* gamma, gray */
  RegWrite(this,0x40,1,0x20); /* FIFO at   0x08000 */
  UploadGammaTable(this,0,this->agammaY); INST_ASSERT();

  UploadGainCorrection(this, 0x2000);
  INST_ASSERT();

  /* for halftone dithering we need one history line */
  this->state.pchBuf=malloc(USB_CHUNK_SIZE);
  this->state.cBacklog=2;
  this->state.ppchLines=calloc(this->state.cBacklog,sizeof(short *));
  if (!this->state.pchBuf || !this->state.ppchLines)
    return FreeState(this,SetError(this,
				   SANE_STATUS_NO_MEM,"no buffers available"));
  for (i=0; i<this->state.cBacklog; i++)
    {
      this->state.ppchLines[i]=calloc(this->state.cxMax+1,
				      sizeof(short)); /* 1 dummy at right edge */
      if (!this->state.ppchLines[i])
	return FreeState(this,SetError(this,
				       SANE_STATUS_NO_MEM,"no buffers available"));
    }

  /* calculate and prepare intermediate line transfer buffer */

  this->state.cchLineOut=(this->mode==gray)
    ? this->state.cxPixel
    : (this->state.cxPixel+7)/8;

  this->state.pchLineOut = malloc(this->state.cchLineOut);
  if (!this->state.pchLineOut)
    return FreeState(this,SetError(this,
				   SANE_STATUS_NO_MEM,
				   "no buffers available"));

  /* start the unit, when all buffers are available */

  RegWrite(this,R_CTL, 1, 0x39); INST_ASSERT();
  RegWrite(this,R_CTL, 1, 0x79); INST_ASSERT();
  RegWrite(this,R_CTL, 1, 0xF9); INST_ASSERT();

  this->state.bScanning = true;
  return SANE_STATUS_GOOD;
}