Fixed 16 bit pnm output. The byte-order was wrong for little-endian

systems. Based on code from Roland Roberts <roland@astrofoto.org>.
Henning Meier-Geinitz <henning@meier-geinitz.de>

configure.in

@@ -39,6 +39,7 @@ AC_AIX
 AC_MINIX
 AC_ISC_POSIX
 AM_PROG_CC_STDC
+AC_C_BIGENDIAN
 
 INCLUDES="${INCLUDES} -I/usr/local/include"
 CPPFLAGS="${CPPFLAGS} -D_GNU_SOURCE"

frontend/scanimage.c

@@ -1016,6 +1016,7 @@ scan_it (void)
     "gray", "RGB", "red", "green", "blue"
   };
   SANE_Word total_bytes = 0, expected_bytes;
+  SANE_Int hang_over = -1;
 
   do
     {
@@ -1061,7 +1062,7 @@ scan_it (void)
 	    case SANE_FRAME_RED:
 	    case SANE_FRAME_GREEN:
 	    case SANE_FRAME_BLUE:
-	      assert ((parm.depth == 8) || (parm.depth == 16));
+	      assert (parm.depth == 8);
 	      must_buffer = 1;
 	      offset = parm.format - SANE_FRAME_RED;
 	      break;
@@ -1107,6 +1108,8 @@ scan_it (void)
 	      image.Bpp = 3;
 	      if (parm.format == SANE_FRAME_GRAY)
 		image.Bpp = 1;
+	      if (parm.depth == 16)
+		image.Bpp *= 2;
 	      image.x = image.width - 1;
 	      image.y = -1;
 	      if (!advance (&image))
@@ -1164,6 +1167,7 @@ scan_it (void)
 		  for (i = 0; i < len; ++i)
 		    {
 		      image.data[offset + i] = buffer[i];
+		      if (image.Bpp == 3 || (offset + i) % 2 == 0)
 			if ((offset + i) % 3 == 0 && !advance (&image))
 			  {
 			    status = SANE_STATUS_NO_MEM;
@@ -1177,6 +1181,7 @@ scan_it (void)
 		  for (i = 0; i < len; ++i)
 		    {
 		      image.data[offset + i] = buffer[i];
+		      if (image.Bpp == 1 || (offset + i) % 2 == 0)
 			if (!advance (&image))
 			  {
 			    status = SANE_STATUS_NO_MEM;
@@ -1187,8 +1192,44 @@ scan_it (void)
 		  break;
 		}
 	    }
-	  else
+	  else /* ! must_buffer */
+  	    {
+	      if ((output_format == OUTPUT_TIFF) || (parm.depth != 16))
 		fwrite (buffer, 1, len, stdout);
+	      else
+	        {
+#if !defined(WORDS_BIGENDIAN)
+		  int i, start = 0;
+		  
+		  /* check if we have saved one byte from the last sane_read */
+		  if (hang_over > -1) 
+		    {
+		      if (len > 0)
+			{
+			  fwrite (buffer, 1, 1, stdout);
+			  buffer[0] = (SANE_Byte) hang_over;
+			  hang_over = -1;
+			  start = 1;
+			}
+		    }
+		  /* now do the byte-swapping */
+		  for (i = start; i < (len - 1); i += 2)
+		    {
+		      unsigned char LSB;
+		      LSB = buffer[i];
+		      buffer[i] = buffer[i+1];
+		      buffer[i+1] = LSB;
+		    }
+		  /* check if we have an odd number of bytes */
+		  if (((len - start) % 2) != 0)
+		    {
+		      hang_over = buffer [len - 1];
+		      len--;
+		    }
+#endif
+		  fwrite (buffer, 1, len, stdout);
+		}
+	    }
 
 	  if (verbose && parm.depth == 8)
 	    {
@@ -1211,7 +1252,23 @@ scan_it (void)
 				 parm.lines, parm.depth, resolution_value);
       else
 	write_pnm_header (parm.format, image.width, image.height, parm.depth);
+      if ((output_format == OUTPUT_TIFF) || (image.Bpp == 1) 
+	  || (image.Bpp == 3))
 	fwrite (image.data, image.Bpp, image.height * image.width, stdout);
+      else /* image.Bpp == 2 or image.Bpp == 6 assumed */
+        {
+#if !defined(WORDS_BIGENDIAN)
+	  int i;
+	  for (i = 0; i < image.Bpp * image.height * image.width; i += 2)
+	    {
+	      unsigned char LSB;
+	      LSB = image.data[i];
+	      image.data[i] = image.data[i+1];
+	      image.data[i+1] = LSB;
+	    }
+#endif
+	  fwrite (image.data, image.Bpp, image.height * image.width, stdout);
+	}
     }
 
 cleanup:
@@ -1219,6 +1276,7 @@ cleanup:
   if (image.data)
     free (image.data);
 
+
   expected_bytes = parm.bytes_per_line * parm.lines * 
     ((parm.format == SANE_FRAME_RGB || parm.format == SANE_FRAME_GRAY)?1:3);
   if (parm.lines < 0)
@@ -1770,7 +1828,6 @@ standard output.\n\
 	}
 
       free (full_optstring);
-
       for (index = 0; index < 2; ++index)
 	if (window[index])
 	  {

include/sane/config.h.in

@@ -8,6 +8,9 @@
 #undef _ALL_SOURCE
 #endif
 
+/* Define if words are stored with the most significant byte first */
+#undef WORDS_BIGENDIAN
+
 /* Define if using alloca.c.  */
 #undef C_ALLOCA