Added function sanei_check_value in addition to the existing

sanei_constrain_value.  It checks if the value of a sane option fits into the
constraint but doesn't try to do any fixing/rounding.

ChangeLog

@@ -1,3 +1,10 @@
+2003-03-04  Henning Meier-Geinitz <henning@meier-geinitz.de>
+
+	* include/sane/sanei.h sanei/sanei_constrain_value.c: Added function
+	  sanei_check_value in addition to the existing sanei_constrain_value.
+	  It checks if the value of a sane option fits into the constraint but
+	  doesn't try to do any fixing/rounding.
+
 2003-03-03  Gerhard Jaeger <gerhard@gjaeger.de>
 	* doc/plustek/Plustek-USB-TODO.txt: update
 	* backend/plustek-devs.c backend/plustek-usb.c backend/plustek-usbhw.c

include/sane/sanei.h

@@ -15,28 +15,133 @@
    You should have received a copy of the GNU General Public License
    along with sane; see the file COPYING.  If not, write to the Free
    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
 
-   This file declares SANE internal routines that are provided to
+/** @file sanei.h
-   simplify backend implementation.  */
+ * Convenience macros and function declarations for backends
+ * @sa sanei_backend.h sanei_thread.h
+ */
+
+/* Doxygen documentation */
+
+/** @mainpage SANEI (SANE internal routines) documentation
+ *
+ * @image html ../sane-logo2.jpg
+ * @section intro Introduction
+ *
+ * The header files in the include/sane/ directory named sanei_*.h provide
+ * function declarations and macros that can be used by every SANE backend.
+ * Their implementations can be found in the sanei/ directory. The code aims
+ * to be platform-independent to avoid lots of \#ifdef code in the backends.
+ * Please use the SANEI functions wherever possible.
+ *
+ * This documentation was created by the use of doxygen, the 
+ * doc/doxygen-sanei.conf configuration file and dcoumentation in the sanei_*.h
+ * files.
+ *
+ * This documenation is far from complete. Any help is appreciated.
+ *
+ * @section additional Additional documentation
+ * - The SANE standard can be found at <a 
+ *   href="http://www.mostang.com/sane/html/">the SANE webserver</a>.
+ * - Information on how to write a backend: <a
+ *   href="../backend-writing.txt">backend-writing.txt</a>.
+ * - General SANE documentation is on <a
+ *   href="http://www.mostang.com/sane/docs.html>the SANE documentation
+ *   page</a>.
+ * 
+ * @section contact Contact 
+ *
+ * The common way to contact the developers of SANE is the sane-devel
+ * mailing list. See the <a
+ * href="http://www.mostang.com/sane/mail.html">mailing list webpage</a>
+ * for details. That's the place to ask questions, report bugs, or announce
+ * a new backend.
+ * 
+ */
 
 #ifndef sanei_h
 #define sanei_h
 
 #include <sane/sane.h>
 
-/* A few convenience macros:  */
+/** @name Public macros and functions
+ * @{
+ */
+/** @def STRINGIFY(x)
+ * Turn parameter into string.
+ */
+/** @def PASTE(x,y)
+ * Concatenate parameters.
+ *
+ */
+/** @def NELEMS(a)
+ * Return number of elements of an array.
+ *
+ */
 
+/** @fn extern SANE_Status sanei_check_value (const SANE_Option_Descriptor * opt, void * value);
+ * Check the constraints of a SANE option.
+ *
+ * @param opt   option to check
+ * @param value value of the option
+ *
+ * @return 
+ * - SANE_STATUS_GOOD     - on success
+ * - SANE_STATUS_INVAL    - if the value doesn't fit inside the constraint
+ *   or any other error occured
+ * @sa sanei_constrain_value()
+ */
+
+/** @fn extern SANE_Status sanei_constrain_value (const SANE_Option_Descriptor * opt, void * value, SANE_Word * info);
+ * Check the constraints of a SANE option and adjust its value if necessary.
+ *
+ * Depending on the type of the option and constraint, value is modified
+ * to fit inside constraint.
+ *
+ * @param opt   option to check
+ * @param value value of the option
+ * @param info  info is set to SANE_INFO_INEXACT if value was changed
+ *
+ * @return 
+ * - SANE_STATUS_GOOD     - on success
+ * - SANE_STATUS_INVAL    - if the function wasn't able to fit value into the
+ *   constraint or any other error occured
+ * @sa sanei_check_value()
+ */
+
+/* @} */
+
+/** @name Private macros
+ * @{
+ */
+/** @def STRINGIFY1(x)
+ * Internal use only.
+ */
+/** @def PASTE1(x,y)
+ * Internal use only.
+ */
+/* @} */
+
+/* A few convenience macros:  */
+/** @hideinitializer */
+#define NELEMS(a)	((int)(sizeof (a) / sizeof (a[0])))
+
+/** @hideinitializer */
 #define STRINGIFY1(x)	#x
+/** @hideinitializer */
 #define STRINGIFY(x)	STRINGIFY1(x)
 
+/** @hideinitializer */
 #define PASTE1(x,y)	x##y
+/** @hideinitializer */
 #define PASTE(x,y)	PASTE1(x,y)
 
-#define NELEMS(a)	((int)(sizeof (a) / sizeof (a[0])))
+extern SANE_Status sanei_check_value (const SANE_Option_Descriptor * opt,
+				      void * value);
 
 extern SANE_Status sanei_constrain_value (const SANE_Option_Descriptor * opt,
 					  void * value, SANE_Word * info);
-extern int sanei_save_values (int fd, SANE_Handle device);
+
-extern int sanei_load_values (int fd, SANE_Handle device);
 
 #endif /* sanei_h */

sanei/sanei_constrain_value.c

@@ -43,10 +43,67 @@
 #include <string.h>
 
 #include <sys/types.h>
+#include <stdlib.h>
 
 #include "sane/sane.h"
 #include "sane/sanei.h"
 
+SANE_Status
+sanei_check_value (const SANE_Option_Descriptor * opt, void * value)
+{
+  const SANE_String_Const * string_list;
+  const SANE_Word * word_list;
+  int i;
+  const SANE_Range * range;
+  SANE_Word w, v;
+  SANE_Bool b;
+  size_t len;
+
+  switch (opt->constraint_type)
+    {
+    case SANE_CONSTRAINT_RANGE:
+      w = *(SANE_Word *) value;
+      range = opt->constraint.range;
+
+      if (w < range->min || w > range->max)
+	return SANE_STATUS_INVAL;
+
+      w = *(SANE_Word *) value;
+
+      if (range->quant)
+	{
+	  v = (w - range->min + range->quant/2) / range->quant;
+	  v = v * range->quant + range->min;
+	  if (v != w)
+	    return SANE_STATUS_INVAL;
+	}
+      break;
+
+    case SANE_CONSTRAINT_WORD_LIST:
+      w = *(SANE_Word *) value;
+      word_list = opt->constraint.word_list;
+      for (i = 1; w != word_list[i]; ++i)
+        if (i >= word_list[0])
+          return SANE_STATUS_INVAL;
+      break;
+
+    case SANE_CONSTRAINT_STRING_LIST:
+      string_list = opt->constraint.string_list;
+      len = strlen (value);
+
+      for (i = 0; string_list[i]; ++i)
+	if (strncmp (value, string_list[i], len) == 0
+	    && len == strlen (string_list[i]))
+	  return SANE_STATUS_GOOD;
+      return SANE_STATUS_INVAL;
+      
+    default:
+      break;
+    }
+  return SANE_STATUS_GOOD;
+}
+
+
 SANE_Status
 sanei_constrain_value (const SANE_Option_Descriptor * opt, void * value,
 		       SANE_Word * info)