Initial import of sane-backends version 1.0.24-1.2

1 files changed, 1343 insertions, 0 deletions

diff --git a/backend/xerox_mfp.c b/backend/xerox_mfp.c
new file mode 100644
index 0000000..2ef7078
--- /dev/null
+++ b/backend/xerox_mfp.c
@@ -0,0 +1,1343 @@
+/*
+ * SANE backend for Xerox Phaser 3200MFP
+ * Copyright 2008 ABC <abc@telekom.ru>
+ *
+ *	Network Scanners Support
+ *	Copyright 2010 Alexander Kuznetsov <acca(at)cpan.org>
+ *
+ * This program is licensed under GPL + SANE exception.
+ * More info at http://www.sane-project.org/license.html
+ */
+
+#define DEBUG_NOT_STATIC
+#define BACKEND_NAME xerox_mfp
+
+#include "../include/sane/config.h"
+#include "../include/lassert.h"
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <math.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include "../include/sane/sane.h"
+#include "../include/sane/sanei.h"
+#include "../include/sane/saneopts.h"
+#include "../include/sane/sanei_thread.h"
+#include "../include/sane/sanei_usb.h"
+#include "../include/sane/sanei_config.h"
+#include "../include/sane/sanei_backend.h"
+#include "xerox_mfp.h"
+
+#define BACKEND_BUILD 13
+#define XEROX_CONFIG_FILE "xerox_mfp.conf"
+
+static const SANE_Device **devlist = NULL;	/* sane_get_devices array */
+static struct device *devices_head = NULL;	/* sane_get_devices list */
+
+enum { TRANSPORT_USB, TRANSPORT_TCP, TRANSPORTS_MAX };
+transport available_transports[TRANSPORTS_MAX] = {
+    { "usb", usb_dev_request, usb_dev_open, usb_dev_close, usb_configure_device },
+    { "tcp", tcp_dev_request, tcp_dev_open, tcp_dev_close, tcp_configure_device },
+};
+
+static int resolv_state(int state)
+{
+  if (state & STATE_DOCUMENT_JAM)
+    return SANE_STATUS_JAMMED;
+  if (state & STATE_NO_DOCUMENT)
+    return SANE_STATUS_NO_DOCS;
+  if (state & STATE_COVER_OPEN)
+    return SANE_STATUS_COVER_OPEN;
+  if (state & STATE_INVALID_AREA)
+    return SANE_STATUS_INVAL; /* sane_start: implies SANE_INFO_RELOAD_OPTIONS */
+  if (state & STATE_WARMING)
+#ifdef SANE_STATUS_WARMING_UP
+    return SANE_STATUS_WARMING_UP;
+#else
+    return SANE_STATUS_DEVICE_BUSY;
+#endif
+  if (state & STATE_LOCKING)
+#ifdef SANE_STATUS_HW_LOCKED
+    return SANE_STATUS_HW_LOCKED;
+#else
+    return SANE_STATUS_JAMMED;
+#endif
+  if (state & ~STATE_NO_ERROR)
+    return SANE_STATUS_DEVICE_BUSY;
+  return 0;
+}
+
+static char *str_cmd(int cmd)
+{
+  switch (cmd) {
+    case CMD_ABORT:		return "ABORT";
+    case CMD_INQUIRY:		return "INQUIRY";
+    case CMD_RESERVE_UNIT:	return "RESERVE_UNIT";
+    case CMD_RELEASE_UNIT:	return "RELEASE_UNIT";
+    case CMD_SET_WINDOW:	return "SET_WINDOW";
+    case CMD_READ:		return "READ";
+    case CMD_READ_IMAGE:	return "READ_IMAGE";
+    case CMD_OBJECT_POSITION:	return "OBJECT_POSITION";
+  }
+  return "unknown";
+}
+
+#define MAX_DUMP 70
+static void dbg_dump(struct device *dev)
+{
+  int i;
+  char dbuf[MAX_DUMP * 3 + 1], *dptr = dbuf;
+  int nzlen = dev->reslen;
+  int dlen = MIN(dev->reslen, MAX_DUMP);
+
+  for (i = dev->reslen - 1; i >= 0; i--, nzlen--)
+    if (dev->res[i] != 0)
+      break;
+
+  dlen = MIN(dlen, nzlen + 1);
+
+  for (i = 0; i < dlen; i++, dptr += 3)
+    sprintf(dptr, " %02x", dev->res[i]);
+
+  DBG (5, "[%lu]%s%s\n", (u_long)dev->reslen, dbuf,
+       (dlen < (int)dev->reslen)? "..." : "");
+}
+
+/* one command to device */
+/* return 0: on error, 1: success */
+static int dev_command (struct device *dev, SANE_Byte * cmd, size_t reqlen)
+{
+  SANE_Status status;
+  size_t sendlen = cmd[3] + 4;
+  SANE_Byte *res = dev->res;
+
+
+  assert (reqlen <= sizeof (dev->res));	/* requested len */
+  dev->reslen = sizeof (dev->res);	/* doing full buffer to flush stalled commands */
+
+  if (cmd[2] == CMD_SET_WINDOW) {
+    /* Set Window have wrong packet length, huh. */
+    sendlen = 25;
+  }
+
+  if (cmd[2] == CMD_READ_IMAGE) {
+    /* Read Image is raw data, don't need to read response */
+    res = NULL;
+  }
+
+  dev->state = 0;
+  DBG (4, ":: dev_command(%s[%#x], %lu)\n", str_cmd(cmd[2]), cmd[2],
+       (u_long)reqlen);
+  status = dev->io->dev_request(dev, cmd, sendlen, res, &dev->reslen);
+  if (status != SANE_STATUS_GOOD) {
+    DBG (1, "%s: dev_request: %s\n", __FUNCTION__, sane_strstatus (status));
+    dev->state = SANE_STATUS_IO_ERROR;
+    return 0;
+  }
+
+  if (!res) {
+    /* if not need response just return success */
+    return 1;
+  }
+
+  /* normal command reply, some sanity checking */
+  if (dev->reslen < reqlen) {
+    DBG (1, "%s: illegal response len %lu, need %lu\n",
+	 __FUNCTION__, (u_long)dev->reslen, (u_long)reqlen);
+    dev->state = SANE_STATUS_IO_ERROR;
+    return 0;
+  } else {
+    size_t pktlen;		/* len specified in packet */
+
+    if (DBG_LEVEL > 3)
+      dbg_dump(dev);
+
+    if (dev->res[0] != RES_CODE) {
+      DBG (2, "%s: illegal data header %02x\n", __FUNCTION__, dev->res[0]);
+      dev->state = SANE_STATUS_IO_ERROR;
+      return 0;
+    }
+    pktlen = dev->res[2] + 3;
+    if (dev->reslen != pktlen) {
+      DBG (2, "%s: illegal response len %lu, should be %lu\n",
+	   __FUNCTION__, (u_long)pktlen, (u_long)dev->reslen);
+      dev->state = SANE_STATUS_IO_ERROR;
+      return 0;
+    }
+    if (dev->reslen > reqlen)
+      DBG (2, "%s: too big packet len %lu, need %lu\n",
+	   __FUNCTION__, (u_long)dev->reslen, (u_long)reqlen);
+  }
+
+  dev->state = 0;
+  if (cmd[2] == CMD_SET_WINDOW ||
+      cmd[2] == CMD_OBJECT_POSITION ||
+      cmd[2] == CMD_READ ||
+      cmd[2] == CMD_RESERVE_UNIT) {
+    if (dev->res[1] == STATUS_BUSY)
+      dev->state = SANE_STATUS_DEVICE_BUSY;
+    else if (dev->res[1] == STATUS_CANCEL)
+      dev->state = SANE_STATUS_CANCELLED;
+    else if (dev->res[1] == STATUS_CHECK)
+      dev->state = resolv_state((cmd[2] == CMD_READ)?
+				(dev->res[12] << 8 | dev->res[13]) :
+				(dev->res[4] << 8 | dev->res[5]));
+
+    if (dev->state)
+      DBG (3, "%s(%s[%#x]): => %d: %s\n",
+	   __FUNCTION__, str_cmd(cmd[2]), cmd[2],
+	   dev->state, sane_strstatus(dev->state));
+  }
+
+  return 1;
+}
+
+/* one short command to device */
+static int dev_cmd (struct device *dev, SANE_Byte command)
+{
+  SANE_Byte cmd[4] = { REQ_CODE_A, REQ_CODE_B };
+  cmd[2] = command;
+  return dev_command (dev, cmd, (command == CMD_INQUIRY)? 70 : 32);
+}
+
+/* stop scanning operation. return previous status */
+static SANE_Status dev_stop(struct device *dev)
+{
+  int state = dev->state;
+
+  DBG (3, "%s: %p, scanning %d, reserved %d\n", __FUNCTION__,
+       (void *)dev, dev->scanning, dev->reserved);
+  dev->scanning = 0;
+
+  /* release */
+  if (!dev->reserved)
+   return state;
+  dev->reserved = 0;
+  dev_cmd(dev, CMD_RELEASE_UNIT);
+  DBG (3, "total image %d*%d size %d (win %d*%d), %d*%d %d data: %d, out %d bytes\n",
+       dev->para.pixels_per_line, dev->para.lines,
+       dev->total_img_size,
+       dev->win_width, dev->win_len,
+       dev->pixels_per_line, dev->ulines, dev->blocks,
+       dev->total_data_size, dev->total_out_size);
+  dev->state = state;
+  return state;
+}
+
+SANE_Status ret_cancel(struct device *dev, SANE_Status ret)
+{
+  dev_cmd(dev, CMD_ABORT);
+  if (dev->scanning) {
+    dev_stop(dev);
+    dev->state = SANE_STATUS_CANCELLED;
+  }
+  return ret;
+}
+
+static int cancelled(struct device *dev)
+{
+  if (dev->cancel)
+    return ret_cancel(dev, 1);
+  return 0;
+}
+
+/* issue command and wait until scanner is not busy */
+/* return 0 on error/blocking, 1 is ok and ready */
+static int dev_cmd_wait(struct device *dev, int cmd)
+{
+  int sleeptime = 10;
+
+  do {
+    if (cancelled(dev))
+      return 0;
+    if (!dev_cmd(dev, cmd)) {
+      dev->state = SANE_STATUS_IO_ERROR;
+      return 0;
+    } else if (dev->state) {
+      if (dev->state != SANE_STATUS_DEVICE_BUSY)
+	return 0;
+      else {
+	if (dev->non_blocking) {
+	  dev->state = SANE_STATUS_GOOD;
+	  return 0;
+	} else {
+	  if (sleeptime > 1000)
+	    sleeptime = 1000;
+	  DBG (4, "(%s) sleeping(%d ms).. [%x %x]\n",
+	       str_cmd(cmd), sleeptime, dev->res[4], dev->res[5]);
+	  usleep(sleeptime * 1000);
+	  if (sleeptime < 1000)
+	    sleeptime *= (sleeptime < 100)? 10 : 2;
+	}
+      } /* BUSY */
+    }
+  } while (dev->state == SANE_STATUS_DEVICE_BUSY);
+
+  return 1;
+}
+
+static int inq_dpi_bits[] = {
+  75, 150, 0, 0,
+  200, 300, 0, 0, 
+  600, 0, 0, 1200,
+  100, 0, 0, 2400,
+  0, 4800, 0, 9600
+};
+
+static int res_dpi_codes[] = {
+  75, 0, 150, 0,
+  0, 300, 0, 600,
+  1200, 200, 100, 2400,
+  4800, 9600
+};
+
+static int SANE_Word_sort(const void * a, const void * b)
+{
+  return *(const SANE_Word *)a - *(const SANE_Word *)b;
+}
+
+/* resolve inquired dpi list to dpi_list array */
+static void resolv_inq_dpi(struct device *dev)
+{
+  unsigned int i;
+  int res = dev->resolutions;
+
+  assert(sizeof(inq_dpi_bits) < sizeof(dev->dpi_list));
+  for (i = 0; i < sizeof(inq_dpi_bits) / sizeof(int); i++)
+    if (inq_dpi_bits[i] && (res & (1 << i)))
+      dev->dpi_list[++dev->dpi_list[0]] = inq_dpi_bits[i];
+  qsort(&dev->dpi_list[1], dev->dpi_list[0], sizeof(SANE_Word), SANE_Word_sort);
+}
+
+static unsigned int dpi_to_code(int dpi)
+{
+  unsigned int i;
+
+  for (i = 0; i < sizeof(res_dpi_codes) / sizeof(int); i++) {
+    if (dpi == res_dpi_codes[i])
+      return i;
+  }
+  return 0;
+}
+
+static int string_match_index(const SANE_String_Const s[], SANE_String m)
+{
+  int i;
+
+  for (i = 0; *s; i++) {
+    SANE_String_Const x = *s++;
+    if (strcasecmp(x, m) == 0)
+      return i;
+  }
+  return 0;
+}
+
+static SANE_String string_match(const SANE_String_Const s[], SANE_String m)
+{
+  return UNCONST(s[string_match_index(s, m)]);
+}
+
+static size_t max_string_size (SANE_String_Const s[])
+{
+  size_t max = 0;
+
+  while (*s) {
+    size_t size = strlen(*s++) + 1;
+    if (size > max)
+      max = size;
+  }
+  return max;
+}
+
+static SANE_String_Const doc_sources[] = {
+  "Flatbed", "ADF", "Auto", NULL
+};
+
+static int doc_source_to_code[] = {
+  0x40, 0x20, 0x80
+};
+
+static SANE_String_Const scan_modes[] = {
+  SANE_VALUE_SCAN_MODE_LINEART,
+  SANE_VALUE_SCAN_MODE_HALFTONE,
+  SANE_VALUE_SCAN_MODE_GRAY,
+  SANE_VALUE_SCAN_MODE_COLOR,
+  NULL
+};
+
+static int scan_mode_to_code[] = {
+  0x00, 0x01, 0x03, 0x05
+};
+
+static SANE_Range threshold = {
+  SANE_FIX(30), SANE_FIX(70), SANE_FIX(10)
+};
+
+static void reset_options(struct device *dev)
+{
+  dev->val[OPT_RESOLUTION].w = 150;
+  dev->val[OPT_MODE].s = string_match(scan_modes, SANE_VALUE_SCAN_MODE_COLOR);
+
+  /* if docs loaded in adf use it as default source, flatbed oterwise */
+  dev->val[OPT_SOURCE].s = UNCONST(doc_sources[(dev->doc_loaded)? 1 : 0]);
+
+  dev->val[OPT_THRESHOLD].w = SANE_FIX(50);
+
+  /* this is reported maximum window size, will be fixed later */
+  dev->win_x_range.min = SANE_FIX(0);
+  dev->win_x_range.max = SANE_FIX((double)dev->max_win_width / PNT_PER_MM);
+  dev->win_x_range.quant = SANE_FIX(1);
+  dev->win_y_range.min = SANE_FIX(0);
+  dev->win_y_range.max = SANE_FIX((double)dev->max_win_len / PNT_PER_MM);
+  dev->win_y_range.quant = SANE_FIX(1);
+  dev->val[OPT_SCAN_TL_X].w = dev->win_x_range.min;
+  dev->val[OPT_SCAN_TL_Y].w = dev->win_y_range.min;
+  dev->val[OPT_SCAN_BR_X].w = dev->win_x_range.max;
+  dev->val[OPT_SCAN_BR_Y].w = dev->win_y_range.max;
+}
+
+static void init_options(struct device *dev)
+{
+  int i;
+
+  for (i = 0; i < NUM_OPTIONS; i++) {
+    dev->opt[i].cap = SANE_CAP_SOFT_SELECT | SANE_CAP_SOFT_DETECT;
+    dev->opt[i].size = sizeof(SANE_Word);
+    dev->opt[i].type = SANE_TYPE_FIXED;
+    dev->val[i].s = NULL;
+  }
+
+  dev->opt[OPT_NUMOPTIONS].name = SANE_NAME_NUM_OPTIONS;
+  dev->opt[OPT_NUMOPTIONS].title = SANE_TITLE_NUM_OPTIONS;
+  dev->opt[OPT_NUMOPTIONS].desc = SANE_DESC_NUM_OPTIONS;
+  dev->opt[OPT_NUMOPTIONS].type = SANE_TYPE_INT;
+  dev->opt[OPT_NUMOPTIONS].cap = SANE_CAP_SOFT_DETECT;
+  dev->val[OPT_NUMOPTIONS].w = NUM_OPTIONS;
+
+  dev->opt[OPT_GROUP_STD].name = SANE_NAME_STANDARD;
+  dev->opt[OPT_GROUP_STD].title = SANE_TITLE_STANDARD;
+  dev->opt[OPT_GROUP_STD].desc = SANE_DESC_STANDARD;
+  dev->opt[OPT_GROUP_STD].type = SANE_TYPE_GROUP;
+  dev->opt[OPT_GROUP_STD].cap = 0;
+
+  dev->opt[OPT_RESOLUTION].name = SANE_NAME_SCAN_RESOLUTION;
+  dev->opt[OPT_RESOLUTION].title = SANE_TITLE_SCAN_RESOLUTION;
+  dev->opt[OPT_RESOLUTION].desc = SANE_DESC_SCAN_RESOLUTION;
+  dev->opt[OPT_RESOLUTION].type = SANE_TYPE_INT;
+  dev->opt[OPT_RESOLUTION].cap = SANE_CAP_SOFT_SELECT|SANE_CAP_SOFT_DETECT;
+  dev->opt[OPT_RESOLUTION].unit = SANE_UNIT_DPI;
+  dev->opt[OPT_RESOLUTION].constraint_type = SANE_CONSTRAINT_WORD_LIST;
+  dev->opt[OPT_RESOLUTION].constraint.word_list = dev->dpi_list;
+
+  dev->opt[OPT_MODE].name = SANE_NAME_SCAN_MODE;
+  dev->opt[OPT_MODE].title = SANE_TITLE_SCAN_MODE;
+  dev->opt[OPT_MODE].desc = SANE_DESC_SCAN_MODE;
+  dev->opt[OPT_MODE].type = SANE_TYPE_STRING;
+  dev->opt[OPT_MODE].size = max_string_size(scan_modes);
+  dev->opt[OPT_MODE].cap = SANE_CAP_SOFT_SELECT|SANE_CAP_SOFT_DETECT;
+  dev->opt[OPT_MODE].constraint_type = SANE_CONSTRAINT_STRING_LIST;
+  dev->opt[OPT_MODE].constraint.string_list = scan_modes;
+
+  dev->opt[OPT_THRESHOLD].name = SANE_NAME_HIGHLIGHT;
+  dev->opt[OPT_THRESHOLD].title = SANE_TITLE_THRESHOLD;
+  dev->opt[OPT_THRESHOLD].desc = SANE_DESC_THRESHOLD;
+  dev->opt[OPT_THRESHOLD].unit = SANE_UNIT_PERCENT;
+  dev->opt[OPT_THRESHOLD].cap = SANE_CAP_SOFT_SELECT|SANE_CAP_SOFT_DETECT;
+  dev->opt[OPT_THRESHOLD].constraint_type = SANE_CONSTRAINT_RANGE;
+  dev->opt[OPT_THRESHOLD].constraint.range = &threshold;
+
+  dev->opt[OPT_SOURCE].name = SANE_NAME_SCAN_SOURCE;
+  dev->opt[OPT_SOURCE].title = SANE_TITLE_SCAN_SOURCE;
+  dev->opt[OPT_SOURCE].desc = SANE_DESC_SCAN_SOURCE;
+  dev->opt[OPT_SOURCE].type = SANE_TYPE_STRING;
+  dev->opt[OPT_SOURCE].size = max_string_size(doc_sources);
+  dev->opt[OPT_SOURCE].cap = SANE_CAP_SOFT_SELECT|SANE_CAP_SOFT_DETECT;
+  dev->opt[OPT_SOURCE].constraint_type = SANE_CONSTRAINT_STRING_LIST;
+  dev->opt[OPT_SOURCE].constraint.string_list = doc_sources;
+
+  dev->opt[OPT_GROUP_GEO].name = SANE_NAME_GEOMETRY;
+  dev->opt[OPT_GROUP_GEO].title = SANE_TITLE_GEOMETRY;
+  dev->opt[OPT_GROUP_GEO].desc = SANE_DESC_GEOMETRY;
+  dev->opt[OPT_GROUP_GEO].type = SANE_TYPE_GROUP;
+  dev->opt[OPT_GROUP_GEO].cap = 0;
+
+  dev->opt[OPT_SCAN_TL_X].name = SANE_NAME_SCAN_TL_X;
+  dev->opt[OPT_SCAN_TL_X].title = SANE_TITLE_SCAN_TL_X;
+  dev->opt[OPT_SCAN_TL_X].desc = SANE_DESC_SCAN_TL_X;
+  dev->opt[OPT_SCAN_TL_X].unit = SANE_UNIT_MM;
+  dev->opt[OPT_SCAN_TL_X].constraint_type = SANE_CONSTRAINT_RANGE;
+  dev->opt[OPT_SCAN_TL_X].constraint.range = &dev->win_x_range;
+
+  dev->opt[OPT_SCAN_TL_Y].name = SANE_NAME_SCAN_TL_Y;
+  dev->opt[OPT_SCAN_TL_Y].title = SANE_TITLE_SCAN_TL_Y;
+  dev->opt[OPT_SCAN_TL_Y].desc = SANE_DESC_SCAN_TL_Y;
+  dev->opt[OPT_SCAN_TL_Y].unit = SANE_UNIT_MM;
+  dev->opt[OPT_SCAN_TL_Y].constraint_type = SANE_CONSTRAINT_RANGE;
+  dev->opt[OPT_SCAN_TL_Y].constraint.range = &dev->win_y_range;
+
+  dev->opt[OPT_SCAN_BR_X].name = SANE_NAME_SCAN_BR_X;
+  dev->opt[OPT_SCAN_BR_X].title = SANE_TITLE_SCAN_BR_X;
+  dev->opt[OPT_SCAN_BR_X].desc = SANE_DESC_SCAN_BR_X;
+  dev->opt[OPT_SCAN_BR_X].unit = SANE_UNIT_MM;
+  dev->opt[OPT_SCAN_BR_X].constraint_type = SANE_CONSTRAINT_RANGE;
+  dev->opt[OPT_SCAN_BR_X].constraint.range = &dev->win_x_range;
+
+  dev->opt[OPT_SCAN_BR_Y].name = SANE_NAME_SCAN_BR_Y;
+  dev->opt[OPT_SCAN_BR_Y].title = SANE_TITLE_SCAN_BR_Y;
+  dev->opt[OPT_SCAN_BR_Y].desc = SANE_DESC_SCAN_BR_Y;
+  dev->opt[OPT_SCAN_BR_Y].unit = SANE_UNIT_MM;
+  dev->opt[OPT_SCAN_BR_Y].constraint_type = SANE_CONSTRAINT_RANGE;
+  dev->opt[OPT_SCAN_BR_Y].constraint.range = &dev->win_y_range;
+}
+
+/* fill parameters from options */
+static void set_parameters(struct device *dev)
+{
+  double px_to_len;
+
+  dev->para.last_frame = SANE_TRUE;
+  dev->para.lines = -1;
+  px_to_len = 1200.0 / dev->val[OPT_RESOLUTION].w;
+#define BETTER_BASEDPI 1
+  /* tests prove that 1200dpi base is very inexact
+   * so I calculated better values for each axis */
+#if BETTER_BASEDPI 
+  px_to_len = 1180.0 / dev->val[OPT_RESOLUTION].w;
+#endif
+  dev->para.pixels_per_line = dev->win_width / px_to_len;
+  dev->para.bytes_per_line = dev->para.pixels_per_line;
+#if BETTER_BASEDPI
+  px_to_len = 1213.9 / dev->val[OPT_RESOLUTION].w;
+#endif
+  dev->para.lines = dev->win_len / px_to_len;
+  if (dev->composition == MODE_LINEART ||
+      dev->composition == MODE_HALFTONE) {
+    dev->para.format = SANE_FRAME_GRAY;
+    dev->para.depth = 1;
+    dev->para.bytes_per_line = (dev->para.pixels_per_line + 7) / 8;
+  } else if (dev->composition == MODE_GRAY8) {
+    dev->para.format = SANE_FRAME_GRAY;
+    dev->para.depth = 8;
+    dev->para.bytes_per_line = dev->para.pixels_per_line;
+  } else if (dev->composition == MODE_RGB24) {
+    dev->para.format = SANE_FRAME_RGB;
+    dev->para.depth = 8;
+    dev->para.bytes_per_line *= 3;
+  } else {
+    /* this will never happen */
+    DBG (1, "%s: impossible image composition %d\n",
+	 __FUNCTION__, dev->composition);
+    dev->para.format = SANE_FRAME_GRAY;
+    dev->para.depth = 8;
+  }
+}
+
+/* resolve all options related to scan window */
+/* called after option changed and in set_window */
+static int fix_window(struct device *dev)
+{
+  double win_width_mm, win_len_mm;
+  int i;
+  int threshold = SANE_UNFIX(dev->val[OPT_THRESHOLD].w);
+
+  dev->resolution = dpi_to_code(dev->val[OPT_RESOLUTION].w);
+  dev->composition = scan_mode_to_code[string_match_index(scan_modes, dev->val[OPT_MODE].s)];
+
+  if (dev->composition == MODE_LINEART ||
+      dev->composition == MODE_HALFTONE) {
+    dev->opt[OPT_THRESHOLD].cap &= ~SANE_CAP_INACTIVE;
+  } else {
+    dev->opt[OPT_THRESHOLD].cap |= SANE_CAP_INACTIVE;
+  }
+  if (threshold < 30) {
+    dev->val[OPT_THRESHOLD].w = SANE_FIX(30);
+  } else if (threshold > 70) {
+    dev->val[OPT_THRESHOLD].w = SANE_FIX(70);
+  }
+  threshold = SANE_UNFIX(dev->val[OPT_THRESHOLD].w);
+  dev->threshold = (threshold - 30) / 10;
+  dev->val[OPT_THRESHOLD].w = SANE_FIX(dev->threshold * 10 + 30);
+
+  dev->doc_source = doc_source_to_code[string_match_index(doc_sources, dev->val[OPT_SOURCE].s)];
+
+  /* max window len is dependent of document source */
+  if (dev->doc_source == DOC_FLATBED ||
+      (dev->doc_source == DOC_AUTO && !dev->doc_loaded))
+    dev->max_len = dev->max_len_fb;
+  else
+    dev->max_len = dev->max_len_adf;
+
+  /* parameters */
+  dev->win_y_range.max = SANE_FIX((double)dev->max_len / PNT_PER_MM);
+
+  /* window sanity checking */
+  for (i = OPT_SCAN_TL_X; i <= OPT_SCAN_BR_Y; i++) {
+    if (dev->val[i].w < dev->opt[i].constraint.range->min)
+      dev->val[i].w = dev->opt[i].constraint.range->min;
+    if (dev->val[i].w > dev->opt[i].constraint.range->max)
+      dev->val[i].w = dev->opt[i].constraint.range->max;
+  }
+
+  if (dev->val[OPT_SCAN_TL_X].w > dev->val[OPT_SCAN_BR_X].w)
+    SWAP_Word(dev->val[OPT_SCAN_TL_X].w, dev->val[OPT_SCAN_BR_X].w);
+  if (dev->val[OPT_SCAN_TL_Y].w > dev->val[OPT_SCAN_BR_Y].w)
+    SWAP_Word(dev->val[OPT_SCAN_TL_Y].w, dev->val[OPT_SCAN_BR_Y].w);
+
+  /* recalculate millimeters to inches */
+  dev->win_off_x = SANE_UNFIX(dev->val[OPT_SCAN_TL_X].w) / MM_PER_INCH;
+  dev->win_off_y = SANE_UNFIX(dev->val[OPT_SCAN_TL_Y].w) / MM_PER_INCH;
+
+  /* calc win size in mm */
+  win_width_mm = SANE_UNFIX(dev->val[OPT_SCAN_BR_X].w) -
+		    SANE_UNFIX(dev->val[OPT_SCAN_TL_X].w);
+  win_len_mm = SANE_UNFIX(dev->val[OPT_SCAN_BR_Y].w) -
+		  SANE_UNFIX(dev->val[OPT_SCAN_TL_Y].w);
+  /* convert mm to 1200 dpi points */
+  dev->win_width = (int)(win_width_mm * PNT_PER_MM);
+  dev->win_len = (int)(win_len_mm * PNT_PER_MM);
+
+  /* don't scan if window is zero size */
+  if (!dev->win_width || !dev->win_len) {
+    /* "The scan cannot be started with the current set of options." */
+    dev->state = SANE_STATUS_INVAL;
+    return 0;
+  }
+
+  return 1;
+}
+
+static int dev_set_window (struct device *dev)
+{
+  SANE_Byte cmd[0x19] = {
+    REQ_CODE_A, REQ_CODE_B, CMD_SET_WINDOW, 0x13, MSG_SCANNING_PARAM
+  };
+
+  if (!fix_window(dev))
+    return 0;
+
+  cmd[0x05] = dev->win_width >> 24;
+  cmd[0x06] = dev->win_width >> 16;
+  cmd[0x07] = dev->win_width >> 8;
+  cmd[0x08] = dev->win_width;
+  cmd[0x09] = dev->win_len >> 24;
+  cmd[0x0a] = dev->win_len >> 16;
+  cmd[0x0b] = dev->win_len >> 8;
+  cmd[0x0c] = dev->win_len;
+  cmd[0x0d] = dev->resolution;		/* x */
+  cmd[0x0e] = dev->resolution;		/* y */
+  cmd[0x0f] = (SANE_Byte)floor(dev->win_off_x);
+  cmd[0x10] = (SANE_Byte)((dev->win_off_x - floor(dev->win_off_x)) * 100);
+  cmd[0x11] = (SANE_Byte)floor(dev->win_off_y);
+  cmd[0x12] = (SANE_Byte)((dev->win_off_y - floor(dev->win_off_y)) * 100);
+  cmd[0x13] = dev->composition;
+  cmd[0x16] = dev->threshold;
+  cmd[0x17] = dev->doc_source;
+
+  DBG (5, "OFF xi: %02x%02x yi: %02x%02x,"
+       " WIN xp: %02x%02x%02x%02x yp %02x%02x%02x%02x,"
+       " MAX %08x %08x\n",
+       cmd[0x0f], cmd[0x10], cmd[0x11], cmd[0x12],
+       cmd[0x05], cmd[0x06], cmd[0x07], cmd[0x08],
+       cmd[0x09], cmd[0x0a], cmd[0x0b], cmd[0x0c],
+       dev->max_win_width, dev->max_win_len);
+
+  return dev_command (dev, cmd, 32);
+}
+
+static SANE_Status
+dev_inquiry (struct device *dev)
+{
+  SANE_Byte *ptr;
+  SANE_Char *optr, *xptr;
+
+  if (!dev_cmd (dev, CMD_INQUIRY))
+    return SANE_STATUS_IO_ERROR;
+  ptr = dev->res;
+  if (ptr[3] != MSG_PRODUCT_INFO) {
+    DBG (1, "%s: illegal INQUIRY response %02x\n", __FUNCTION__, ptr[3]);
+    return SANE_STATUS_IO_ERROR;
+  }
+
+  /* parse reported manufacturer/product names */
+  dev->sane.vendor = optr = (SANE_Char *) malloc (33);
+  for (ptr += 4; ptr < &dev->res[0x24] && *ptr && *ptr != ' ';)
+    *optr++ = *ptr++;
+  *optr++ = 0;
+
+  for (; ptr < &dev->res[0x24] && (!*ptr || *ptr == ' '); ptr++)
+    /* skip spaces */;
+
+  dev->sane.model = optr = (SANE_Char *) malloc (33);
+  xptr = optr;			/* is last non space character + 1 */
+  for (; ptr < &dev->res[0x24] && *ptr;) {
+    if (*ptr != ' ')
+      xptr = optr + 1;
+    *optr++ = *ptr++;
+  }
+  *optr++ = 0;
+  *xptr = 0;
+
+  DBG (1, "%s: found %s/%s\n", __FUNCTION__, dev->sane.vendor, dev->sane.model);
+  dev->sane.type = strdup ("multi-function peripheral");
+
+  dev->resolutions = dev->res[0x37] << 16 |
+    dev->res[0x24] << 8 |
+    dev->res[0x25];
+  dev->compositions = dev->res[0x27];
+  dev->max_win_width = dev->res[0x28] << 24 |
+    dev->res[0x29] << 16 |
+    dev->res[0x2a] << 8 |
+    dev->res[0x2b];
+  dev->max_win_len = dev->res[0x2c] << 24 |
+    dev->res[0x2d] << 16 |
+    dev->res[0x2e] << 8 |
+    dev->res[0x2f];
+  dev->max_len_adf = dev->res[0x38] << 24 |
+    dev->res[0x39] << 16 |
+    dev->res[0x3a] << 8 |
+    dev->res[0x3b];
+  dev->max_len_fb = dev->res[0x3c] << 24 |
+    dev->res[0x3d] << 16 |
+    dev->res[0x3e] << 8 |
+    dev->res[0x3f];
+  dev->line_order = dev->res[0x31];
+  dev->doc_loaded = (dev->res[0x35] == 0x02) &&
+    (dev->res[0x26] & 0x03);
+
+  init_options(dev);
+  reset_options(dev);
+  fix_window(dev);
+  set_parameters(dev);
+  resolv_inq_dpi(dev);
+
+  return SANE_STATUS_GOOD;
+}
+
+const SANE_Option_Descriptor *
+sane_get_option_descriptor (SANE_Handle h, SANE_Int opt)
+{
+  struct device *dev = h;
+
+  DBG (3, "%s: %p, %d\n", __FUNCTION__, h, opt);
+  if (opt >= NUM_OPTIONS || opt < 0)
+    return NULL;
+  return &dev->opt[opt];
+}
+
+SANE_Status
+sane_control_option (SANE_Handle h, SANE_Int opt, SANE_Action act,
+		     void *val, SANE_Word * info)
+{
+  struct device *dev = h;
+
+  DBG (3, "%s: %p, %d, <%d>, %p, %p\n", __FUNCTION__, h, opt, act, val, (void *)info);
+  if (!dev || opt >= NUM_OPTIONS || opt < 0)
+    return SANE_STATUS_INVAL;
+
+  if (info)
+    *info = 0;
+
+  if (act == SANE_ACTION_GET_VALUE) { /* GET */
+    if (dev->opt[opt].type == SANE_TYPE_STRING)
+      strcpy(val, dev->val[opt].s);
+    else
+      *(SANE_Word *)val = dev->val[opt].w;
+  } else if (act == SANE_ACTION_SET_VALUE) { /* SET */
+    SANE_Parameters xpara = dev->para;
+    SANE_Option_Descriptor xopt[NUM_OPTIONS];
+    Option_Value xval[NUM_OPTIONS];
+    int i;
+
+    if (dev->opt[opt].constraint_type == SANE_CONSTRAINT_STRING_LIST) {
+      dev->val[opt].s = string_match(dev->opt[opt].constraint.string_list, val);
+      if (info && strcasecmp(dev->val[opt].s, val))
+	*info |= SANE_INFO_INEXACT;
+    } else if (opt == OPT_RESOLUTION)
+      dev->val[opt].w = res_dpi_codes[dpi_to_code(*(SANE_Word *)val)];
+    else
+      dev->val[opt].w = *(SANE_Word *)val;
+
+    memcpy(&xopt, &dev->opt, sizeof(xopt));
+    memcpy(&xval, &dev->val, sizeof(xval));
+    fix_window(dev);
+    set_parameters(dev);
+
+    /* check for side effects */
+    if (info) {
+      if (memcmp(&xpara, &dev->para, sizeof(xpara)))
+	*info |= SANE_INFO_RELOAD_PARAMS;
+      if (memcmp(&xopt, &dev->opt, sizeof(xopt)))
+	*info |= SANE_INFO_RELOAD_OPTIONS;
+      for (i = 0; i < NUM_OPTIONS; i++)
+	if (xval[i].w != dev->val[i].w) {
+	  if (i == opt)
+	    *info |= SANE_INFO_INEXACT;
+	  else
+	    *info |= SANE_INFO_RELOAD_OPTIONS;
+	}
+    }
+  }
+
+  DBG (4, "%s: %d, <%d> => %08x, %x\n", __FUNCTION__, opt, act,
+       val? *(SANE_Word *)val : 0, info? *info : 0);
+  return SANE_STATUS_GOOD;
+}
+
+static void
+dev_free (struct device *dev)
+{
+  if (!dev)
+    return;
+
+  if (dev->sane.name)
+    free (UNCONST(dev->sane.name));
+  if (dev->sane.vendor)
+    free (UNCONST(dev->sane.vendor));
+  if (dev->sane.model)
+    free (UNCONST(dev->sane.model));
+  if (dev->sane.type)
+    free (UNCONST(dev->sane.type));
+  if (dev->data)
+    free(dev->data);
+  memset (dev, 0, sizeof (*dev));
+  free (dev);
+}
+
+static void
+free_devices (void)
+{
+  int i;
+  struct device *next;
+  struct device *dev;
+
+  if (devlist) {
+    free (devlist);
+    devlist = NULL;
+  }
+  for (i = 0, dev = devices_head; dev; dev = next) {
+    next = dev->next;
+    dev_free (dev);
+  }
+  devices_head = NULL;
+}
+
+static transport *tr_from_devname(SANE_String_Const devname)
+{
+  if (strncmp("tcp", devname, 3) == 0)
+    return &available_transports[TRANSPORT_TCP];
+  return &available_transports[TRANSPORT_USB];
+}
+
+static SANE_Status
+list_one_device (SANE_String_Const devname)
+{
+  struct device *dev;
+  SANE_Status status;
+  transport *tr;
+
+  DBG (4, "%s: %s\n", __FUNCTION__, devname);
+
+  for (dev = devices_head; dev; dev = dev->next) {
+    if (strcmp (dev->sane.name, devname) == 0)
+      return SANE_STATUS_GOOD;
+  }
+
+  tr = tr_from_devname(devname);
+
+  dev = calloc (1, sizeof (struct device));
+  if (dev == NULL)
+    return SANE_STATUS_NO_MEM;
+
+  dev->sane.name = strdup (devname);
+  dev->io = tr;
+  status = tr->dev_open (dev);
+  if (status != SANE_STATUS_GOOD) {
+    dev_free (dev);
+    return status;
+  }
+
+/*  status = dev_cmd (dev, CMD_ABORT);*/
+  status = dev_inquiry (dev);
+  tr->dev_close (dev);
+  if (status != SANE_STATUS_GOOD) {
+    DBG (1, "%s: dev_inquiry(%s): %s\n", __FUNCTION__,
+	 dev->sane.name, sane_strstatus (status));
+    dev_free (dev);
+    return status;
+  }
+
+  /* good device, add it to list */
+  dev->next = devices_head;
+  devices_head = dev;
+  return SANE_STATUS_GOOD;
+}
+
+/* SANE API ignores return code of this callback */
+static SANE_Status
+list_conf_devices (UNUSED (SANEI_Config * config), const char *devname)
+{
+  return tr_from_devname(devname)->configure_device(devname, list_one_device);
+}
+
+SANE_Status
+sane_init (SANE_Int * version_code, SANE_Auth_Callback cb)
+{
+  DBG_INIT ();
+  DBG (2, "sane_init: Xerox backend (build %d), version %s null, authorize %s null\n", BACKEND_BUILD,
+       (version_code) ? "!=" : "==", (cb) ? "!=" : "==");
+
+  if (version_code)
+    *version_code = SANE_VERSION_CODE (V_MAJOR, V_MINOR, BACKEND_BUILD);
+
+  sanei_usb_init ();
+  return SANE_STATUS_GOOD;
+}
+
+void
+sane_exit (void)
+{
+  struct device *dev;
+
+  for (dev = devices_head; dev; dev = dev->next)
+    if (dev->dn != -1)
+      sane_close(dev); /* implies flush */
+  
+  free_devices ();
+}
+
+SANE_Status
+sane_get_devices (const SANE_Device *** device_list, SANE_Bool local)
+{
+  SANEI_Config config;
+  struct device *dev;
+  int dev_count;
+  int i;
+
+  DBG (3, "%s: %p, %d\n", __FUNCTION__, (const void *)device_list, local);
+
+  if (devlist) {
+    if (device_list)
+      *device_list = devlist;
+    return SANE_STATUS_GOOD;
+  }
+
+  free_devices ();
+
+  config.count = 0;
+  config.descriptors = NULL;
+  config.values = NULL;
+  sanei_configure_attach (XEROX_CONFIG_FILE, &config, list_conf_devices);
+
+  for (dev_count = 0, dev = devices_head; dev; dev = dev->next)
+    dev_count++;
+
+  devlist = malloc ((dev_count + 1) * sizeof (*devlist));
+  if (!devlist)
+    {
+      DBG (1, "%s: malloc: no memory\n", __FUNCTION__);
+      return SANE_STATUS_NO_MEM;
+    }
+
+  for (i = 0, dev = devices_head; dev; dev = dev->next)
+    devlist[i++] = &dev->sane;
+  devlist[i++] = NULL;
+
+  if (device_list)
+    *device_list = devlist;
+  return SANE_STATUS_GOOD;
+}
+
+void
+sane_close (SANE_Handle h)
+{
+  struct device *dev = h;
+
+  if (!dev)
+    return;
+
+  DBG (3, "%s: %p (%s)\n", __FUNCTION__, (void *)dev, dev->sane.name);
+  dev->io->dev_close(dev);
+}
+
+SANE_Status
+sane_open (SANE_String_Const name, SANE_Handle * h)
+{
+  struct device *dev;
+
+  DBG (3, "%s: '%s'\n", __FUNCTION__, name);
+
+  if (!devlist)
+    sane_get_devices (NULL, SANE_TRUE);
+
+  if (!name || !*name) {
+    /* special case of empty name: open first available device */
+    for (dev = devices_head; dev; dev = dev->next) {
+      if (dev->dn != -1) {
+	if (sane_open (dev->sane.name, h) == SANE_STATUS_GOOD)
+	  return SANE_STATUS_GOOD;
+      }
+    }
+  } else {
+    for (dev = devices_head; dev; dev = dev->next) {
+      if (strcmp(name, dev->sane.name) == 0) {
+	*h = dev;
+	return dev->io->dev_open(dev);
+      }
+    }
+  }
+
+  return SANE_STATUS_INVAL;
+}
+
+SANE_Status
+sane_get_parameters (SANE_Handle h, SANE_Parameters * para)
+{
+  struct device *dev = h;
+
+  DBG (3, "%s: %p, %p\n", __FUNCTION__, h, (void *)para);
+  if (!para)
+    return SANE_STATUS_INVAL;
+
+  *para = dev->para;
+  return SANE_STATUS_GOOD;
+}
+
+/* check if image data is ready, and wait if not */
+/* 1: image is acquired, 0: error or non_blocking mode */
+static int dev_acquire(struct device *dev)
+{
+  if (!dev_cmd_wait(dev, CMD_READ))
+    return dev->state;
+
+  dev->state = SANE_STATUS_GOOD;
+  dev->vertical = dev->res[0x08] << 8 | dev->res[0x09];
+  dev->horizontal = dev->res[0x0a] << 8 | dev->res[0x0b];
+  dev->blocklen = dev->res[4] << 24 |
+    dev->res[5] << 16 |
+    dev->res[6] << 8 |
+    dev->res[7];
+  dev->final_block = (dev->res[3] == MSG_END_BLOCK)? 1 : 0;
+
+  dev->pixels_per_line = dev->horizontal;
+  dev->bytes_per_line = dev->horizontal;
+
+  if (dev->composition == MODE_RGB24)
+    dev->bytes_per_line *= 3;
+  else if (dev->composition == MODE_LINEART ||
+	   dev->composition == MODE_HALFTONE)
+    dev->pixels_per_line *= 8;
+
+  DBG (4, "acquiring, size per band v: %d, h: %d, %sblock: %d, slack: %d\n",
+       dev->vertical, dev->horizontal, dev->final_block? "last " : "",
+       dev->blocklen, dev->blocklen - (dev->vertical * dev->bytes_per_line));
+
+  if (dev->bytes_per_line > DATASIZE) {
+    DBG (1, "%s: unsupported line size: %d bytes > %d\n",
+	 __FUNCTION__, dev->bytes_per_line, DATASIZE);
+    return ret_cancel(dev, SANE_STATUS_NO_MEM);
+  }
+
+  dev->reading = 0; /* need to issue READ_IMAGE */
+
+  dev->dataindex = 0;
+  dev->datalen = 0;
+  dev->dataoff = 0;
+
+  return 1;
+}
+
+static int fill_slack(struct device *dev, SANE_Byte *buf, int maxlen)
+{
+  const int slack = dev->total_img_size - dev->total_out_size;
+  const int havelen = MIN(slack, maxlen);
+  int j;
+
+  if (havelen <= 0)
+    return 0;
+  for (j = 0; j < havelen; j++)
+    buf[j] = 255;
+  return havelen;
+}
+
+static int copy_plain_trim(struct device *dev, SANE_Byte *buf, int maxlen, int *olenp)
+{
+  int j;
+  const int linesize = dev->bytes_per_line;
+  int k = dev->dataindex;
+  *olenp = 0;
+  for (j = 0; j < dev->datalen && *olenp < maxlen; j++, k++) {
+    const int x = k % linesize;
+    const int y = k / linesize;
+    if (y >= dev->vertical)
+      break; /* slack */
+    if (x < dev->para.bytes_per_line &&
+	(y + dev->y_off) < dev->para.lines) {
+      *buf++ = dev->data[(dev->dataoff + j) & DATAMASK];
+      (*olenp)++;
+    }
+  }
+  dev->dataindex = k;
+  return j;
+}
+
+/* return: how much data could be freed from cyclic buffer */
+/* convert from RRGGBB to RGBRGB */
+static int copy_mix_bands_trim(struct device *dev, SANE_Byte *buf, int maxlen, int *olenp) {
+  int j;
+
+  const int linesize = dev->bytes_per_line; /* caching real line size */
+
+  /* line number of the head of input buffer,
+   * input buffer is always aligned to whole line */
+  const int y_off = dev->dataindex / linesize;
+
+  int k = dev->dataindex; /* caching current index of input buffer */
+
+  /* can only copy as much as full lines we have */
+  int havelen = dev->datalen / linesize * linesize - k % linesize;
+
+  const int bands = 3;
+  *olenp = 0;
+
+  /* while we have data && they can receive */
+  for (j = 0; j < havelen && *olenp < maxlen; j++, k++) {
+    const int band = (k % bands) * dev->horizontal;
+    const int x = k % linesize / bands;
+    const int y = k / linesize - y_off; /* y relative to buffer head */
+    const int y_rly = y + y_off + dev->y_off; /* global y */
+
+    if (x < dev->para.pixels_per_line &&
+	y_rly < dev->para.lines) {
+      *buf++ = dev->data[(dev->dataoff + band + x + y * linesize) & DATAMASK];
+      (*olenp)++;
+    }
+  }
+  dev->dataindex = k;
+
+  /* how much full lines are finished */
+  return (k / linesize - y_off) * linesize;
+}
+
+SANE_Status
+sane_read (SANE_Handle h, SANE_Byte * buf, SANE_Int maxlen, SANE_Int * lenp)
+{
+  SANE_Status status;
+  struct device *dev = h;
+
+  DBG (3, "%s: %p, %p, %d, %p\n", __FUNCTION__, h, buf, maxlen, (void *)lenp);
+
+  if (lenp)
+    *lenp = 0;
+  if (!dev)
+    return SANE_STATUS_INVAL;
+
+  if (!dev->scanning)
+    return SANE_STATUS_EOF;
+
+  /* if there is no data to read or output from buffer */
+  if (!dev->blocklen && dev->datalen <= PADDING_SIZE) {
+
+    /* and we don't need to acquire next block */
+    if (dev->final_block) {
+      int slack = dev->total_img_size - dev->total_out_size;
+
+      /* but we may need to fill slack */
+      if (buf && lenp && slack > 0) {
+	*lenp = fill_slack(dev, buf, maxlen);
+	dev->total_out_size += *lenp;
+	DBG (9, "<> slack: %d, filled: %d, maxlen %d\n",
+	     slack, *lenp, maxlen);
+	return SANE_STATUS_GOOD;
+      } else if (slack < 0) {
+	/* this will never happen */
+	DBG(1, "image overflow %d bytes\n", dev->total_img_size - dev->total_out_size);
+      }
+
+      /* that's all */
+      dev_stop(dev);
+      return SANE_STATUS_EOF;
+    }
+
+    /* queue next image block */
+    if (!dev_acquire(dev))
+      return dev->state;
+  }
+
+  if (!dev->reading) {
+    if (cancelled(dev))
+      return dev->state;
+    DBG (5, "READ_IMAGE\n");
+    if (!dev_cmd(dev, CMD_READ_IMAGE))
+      return SANE_STATUS_IO_ERROR;
+    dev->reading++;
+    dev->ulines += dev->vertical;
+    dev->y_off = dev->ulines - dev->vertical;
+    dev->total_data_size += dev->blocklen;
+    dev->blocks++;
+  }
+
+  do {
+    size_t datalen;
+    int clrlen; /* cleared lines len */
+    int olen; /* output len */
+
+    /* read as much data into the buffer */
+    datalen = DATAROOM(dev) & USB_BLOCK_MASK;
+    while (datalen && dev->blocklen) {
+      SANE_Byte *rbuf = dev->data + DATATAIL(dev);
+
+      DBG (9, "<> request len: %lu, [%d, %d; %d]\n",
+	   (u_long)datalen, dev->dataoff, DATATAIL(dev), dev->datalen);
+      if ((status = dev->io->dev_request(dev, NULL, 0, rbuf, &datalen)) !=
+	  SANE_STATUS_GOOD)
+	return status;
+      dev->datalen += datalen;
+      dev->blocklen -= datalen;
+      DBG (9, "<> got %lu, [%d, %d; %d]\n",
+	   (u_long)datalen, dev->dataoff, DATATAIL(dev), dev->datalen);
+      if (dev->blocklen < 0)
+	return ret_cancel(dev, SANE_STATUS_IO_ERROR);
+
+      datalen = DATAROOM(dev) & USB_BLOCK_MASK;
+    }
+
+    if (buf && lenp) { /* read mode */
+      /* copy will do minimal of valid data */
+      if (dev->para.format == SANE_FRAME_RGB && dev->line_order)
+	clrlen = copy_mix_bands_trim(dev, buf, maxlen, &olen);
+      else
+	clrlen = copy_plain_trim(dev, buf, maxlen, &olen);
+
+      dev->datalen -= clrlen;
+      dev->dataoff = (dev->dataoff + clrlen) & DATAMASK;
+      buf += olen;
+      maxlen -= olen;
+      *lenp += olen;
+      dev->total_out_size += olen;
+
+      DBG (9, "<> olen: %d, clrlen: %d, blocklen: %d/%d, maxlen %d (%d %d %d)\n",
+	   olen, clrlen, dev->blocklen, dev->datalen, maxlen,
+	   dev->dataindex / dev->bytes_per_line + dev->y_off,
+	   dev->y_off, dev->para.lines);
+
+      /* slack beyond last line */
+      if (dev->dataindex / dev->bytes_per_line + dev->y_off >= dev->para.lines) {
+	dev->datalen = 0;
+	dev->dataoff = 0;
+      }
+
+      if (!clrlen || maxlen <= 0)
+	break;
+    } else { /* flush mode */
+      dev->datalen = 0;
+      dev->dataoff = 0;
+    }
+
+  } while (dev->blocklen);
+
+  if (lenp)
+    DBG (9, " ==> %d\n", *lenp);
+
+  return SANE_STATUS_GOOD;
+}
+
+SANE_Status
+sane_start (SANE_Handle h)
+{
+  struct device *dev = h;
+
+  DBG (3, "%s: %p\n", __FUNCTION__, h);
+
+  dev->cancel = 0;
+  dev->scanning = 0;
+  dev->total_img_size = 0;
+  dev->total_out_size = 0;
+  dev->total_data_size = 0;
+  dev->blocks = 0;
+
+  if (!dev->reserved) {
+    if (!dev_cmd_wait(dev, CMD_RESERVE_UNIT))
+      return dev->state;
+    dev->reserved++;
+  }
+
+  if (!dev_set_window(dev) ||
+      (dev->state && dev->state != SANE_STATUS_DEVICE_BUSY))
+    return dev_stop(dev);
+
+  if (!dev_cmd_wait(dev, CMD_OBJECT_POSITION))
+    return dev_stop(dev);
+
+  if (!dev_cmd(dev, CMD_READ) ||
+      (dev->state && dev->state != SANE_STATUS_DEVICE_BUSY))
+    return dev_stop(dev);
+
+  dev->scanning = 1;
+  dev->final_block = 0;
+  dev->blocklen = 0;
+  dev->pixels_per_line = 0;
+  dev->bytes_per_line = 0;
+  dev->ulines = 0;
+
+  set_parameters(dev);
+
+  if (!dev->data && !(dev->data = malloc(DATASIZE)))
+    return ret_cancel(dev, SANE_STATUS_NO_MEM);
+
+  if (!dev_acquire(dev))
+    return dev->state;
+
+  /* make sure to have dev->para <= of real size */
+  if (dev->para.pixels_per_line > dev->pixels_per_line) {
+    dev->para.pixels_per_line = dev->pixels_per_line;
+    dev->para.bytes_per_line = dev->pixels_per_line;
+  }
+
+  if (dev->composition == MODE_RGB24)
+    dev->para.bytes_per_line = dev->para.pixels_per_line * 3;
+  else if (dev->composition == MODE_LINEART ||
+	   dev->composition == MODE_HALFTONE) {
+    dev->para.bytes_per_line = (dev->para.pixels_per_line + 7) / 8;
+    dev->para.pixels_per_line = dev->para.bytes_per_line * 8;
+  } else {
+    dev->para.bytes_per_line = dev->para.pixels_per_line;
+  }
+
+  dev->total_img_size = dev->para.bytes_per_line * dev->para.lines;
+
+  return SANE_STATUS_GOOD;
+}
+
+SANE_Status sane_set_io_mode (SANE_Handle h, SANE_Bool non_blocking)
+{
+  struct device *dev = h;
+
+  DBG (3, "%s: %p, %d\n", __FUNCTION__, h, non_blocking);
+
+  if (non_blocking)
+    return SANE_STATUS_UNSUPPORTED;
+
+  dev->non_blocking = non_blocking;
+  return SANE_STATUS_GOOD;
+}
+
+SANE_Status sane_get_select_fd (SANE_Handle h, SANE_Int * fdp)
+{
+  DBG (3, "%s: %p, %p\n", __FUNCTION__, h, (void *)fdp);
+  /* supporting of this will require thread creation */
+  return SANE_STATUS_UNSUPPORTED;
+}
+
+void sane_cancel (SANE_Handle h)
+{
+  struct device *dev = h;
+
+  DBG (3, "%s: %p\n", __FUNCTION__, h);
+  dev->cancel = 1;
+}
+
+/* xerox_mfp.c */