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backends/graphics/default-palette.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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 3 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef BACKENDS_GRAPHICS_DEFAULT_PALETTE_H
+#define BACKENDS_GRAPHICS_DEFAULT_PALETTE_H
+
+#include "graphics/paletteman.h"
+
+/**
+ * This is a default implementation of the PaletteManager interface
+ * which ensures that grabPalette works as specified. Of course
+ * it is still necessary to provide code that actually updates
+ * the (possibly emulated) "hardware" palette of the backend.
+ * For this purpose, implement the abstract setPaletteIntern
+ * method.
+ */
+class DefaultPaletteManager : public PaletteManager {
+protected:
+	byte _palette[3 * 256];
+
+	/**
+	 * Subclasses should only implement this method and none of the others.
+	 * Its semantics are like that of setPalette, only that it does not need
+	 * to worry about making it possible to query the palette values once they
+	 * have been set.
+	 */
+	virtual void setPaletteIntern(const byte *colors, uint start, uint num) = 0;
+
+public:
+	void setPalette(const byte *colors, uint start, uint num) {
+		assert(start + num <= 256);
+		memcpy(_palette + 3 * start, colors, 3 * num);
+		setPaletteIntern(colors, start, num);
+	}
+	void grabPalette(byte *colors, uint start, uint num) const {
+		assert(start + num <= 256);
+		memcpy(colors, _palette + 3 * start, 3 * num);
+	}
+};
+
+#endif