genesys: Extract conversion of ScanColorMode to separate functions

backend/genesys/enums.cpp

@@ -70,4 +70,29 @@ ScanMethod option_string_to_scan_method(const std::string& str)
     throw SaneException("Unknown scan method option %s", str.c_str());
 }
 
+const char* scan_color_mode_to_option_string(ScanColorMode mode)
+{
+    switch (mode) {
+        case ScanColorMode::COLOR_SINGLE_PASS: return SANE_VALUE_SCAN_MODE_COLOR;
+        case ScanColorMode::GRAY: return SANE_VALUE_SCAN_MODE_GRAY;
+        case ScanColorMode::HALFTONE: return SANE_VALUE_SCAN_MODE_HALFTONE;
+        case ScanColorMode::LINEART: return SANE_VALUE_SCAN_MODE_LINEART;
+    }
+    throw SaneException("Unknown scan mode %d", static_cast<unsigned>(mode));
+}
+
+ScanColorMode option_string_to_scan_color_mode(const std::string& str)
+{
+    if (str == SANE_VALUE_SCAN_MODE_COLOR) {
+        return ScanColorMode::COLOR_SINGLE_PASS;
+    } else if (str == SANE_VALUE_SCAN_MODE_GRAY) {
+        return ScanColorMode::GRAY;
+    } else if (str == SANE_VALUE_SCAN_MODE_HALFTONE) {
+        return ScanColorMode::HALFTONE;
+    } else if (str == SANE_VALUE_SCAN_MODE_LINEART) {
+        return ScanColorMode::LINEART;
+    }
+    throw SaneException("Unknown scan color mode %s", str.c_str());
+}
+
 } // namespace genesys

backend/genesys/enums.h

@@ -94,6 +94,8 @@ inline void serialize(std::ostream& str, ScanColorMode& x)
     serialize(str, value);
 }
 
+const char* scan_color_mode_to_option_string(ScanColorMode mode);
+ScanColorMode option_string_to_scan_color_mode(const std::string& str);
 
 enum class ColorFilter : unsigned {
     RED = 0,

backend/genesys/genesys.cpp

@@ -3511,15 +3511,7 @@ static void calc_parameters(Genesys_Scanner* s)
         bytes_per_line *= 3;
     }
 
-    if (s->mode == SANE_VALUE_SCAN_MODE_COLOR) {
-        s->dev->settings.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
-    } else if (s->mode == SANE_VALUE_SCAN_MODE_GRAY) {
-        s->dev->settings.scan_mode = ScanColorMode::GRAY;
-    } else if (s->mode == SANE_TITLE_HALFTONE) {
-        s->dev->settings.scan_mode = ScanColorMode::HALFTONE;
-    } else {				/* Lineart */
-        s->dev->settings.scan_mode = ScanColorMode::LINEART;
-    }
+    s->dev->settings.scan_mode = option_string_to_scan_color_mode(s->mode);
 
   s->dev->settings.lines = s->params.lines;
     s->dev->settings.pixels = pixels_per_line;