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engines/tinsel/scn.cpp

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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/>.
+ *
+ * A (some would say very) small collection of utility functions.
+ */
+
+#include "tinsel/dw.h"
+#include "tinsel/film.h"
+#include "tinsel/handle.h"
+#include "tinsel/multiobj.h"
+#include "tinsel/scn.h"
+#include "tinsel/tinsel.h"	// for _vm
+
+namespace Tinsel {
+
+/**
+ * Given a scene handle and a chunk id, gets the scene in RAM and
+ * locates the requested chunk.
+ * @param handle			Scene handle
+ * @param chunk				Chunk Id
+ */
+byte *FindChunk(SCNHANDLE handle, uint32 chunk) {
+	byte *bptr = _vm->_handle->LockMem(handle);
+	uint32 *lptr = (uint32 *)bptr;
+	uint32 add;
+
+	// Initial adjustment for Tinsel 1 chunk types
+	if ((TinselVersion <= 1) && (chunk >= CHUNK_SCENE) &&
+		(chunk != CHUNK_MBSTRING))
+		--chunk;
+
+	// V0 chunk types can be found by subtracting 2 from the
+	// chunk type. Note that CHUNK_STRING and CHUNK_BITMAP are
+	// the same in V0 and V1
+	if (TinselVersion == 0 &&
+		chunk != CHUNK_STRING && chunk != CHUNK_BITMAP)
+		chunk -= 0x2L;
+
+	while (1) {
+		if (READ_32(lptr) == chunk)
+			return (byte *)(lptr + 2);
+
+		++lptr;
+		add = READ_32(lptr);
+
+		if (!add)
+			// End of file reached
+			return NULL;
+
+		// Move to next chunk
+		lptr = (uint32 *)(bptr + add);
+	}
+}
+
+} // End of namespace Tinsel