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image/codecs/indeo/vlc.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/>.
+ *
+ */
+
+#include "common/scummsys.h"
+
+/* VLC code
+ *
+ * Original copyright note: * Intel Indeo 4 (IV41, IV42, etc.) video decoder for ffmpeg
+ * written, produced, and directed by Alan Smithee
+ */
+
+#ifndef IMAGE_CODECS_INDEO_VLC_H
+#define IMAGE_CODECS_INDEO_VLC_H
+
+#include "image/codecs/indeo/get_bits.h"
+
+namespace Image {
+namespace Indeo {
+
+#define VLC_TYPE int16
+
+enum VLCFlag {
+	INIT_VLC_LE             = 2,
+	INIT_VLC_USE_NEW_STATIC = 4
+};
+
+struct VLCcode {
+	uint8 bits;
+	uint16 symbol;
+
+	/**
+	 * codeword, with the first bit-to-be-read in the msb
+	 * (even if intended for a little-endian bitstream reader)
+	 */
+	uint32 code;
+};
+
+struct VLC {
+private:
+	static int compareVlcSpec(const void *a, const void *b);
+
+	/**
+	 * Gets a value of a given size from a table
+	 * @param table		Table to get data from
+	 * @param idx		Index of value to retrieve
+	 * @param wrap		Size of elements with alignment
+	 * @param size		Size of elements
+	 */
+	static uint getData(const void *table, uint idx, uint wrap, uint size);
+public:
+	int _bits;
+	VLC_TYPE (*_table)[2];	///< code, bits
+	int _tableSize, _tableAllocated;
+
+	VLC();
+
+	/* Build VLC decoding tables suitable for use with get_vlc().
+
+	'nbBits' sets the decoding table size (2^nbBits) entries. The
+	bigger it is, the faster is the decoding. But it should not be too
+	big to save memory and L1 cache. '9' is a good compromise.
+
+	'nbCodes' : number of vlcs codes
+
+	'bits' : table which gives the size (in bits) of each vlc code.
+
+	'codes' : table which gives the bit pattern of of each vlc code.
+
+	'symbols' : table which gives the values to be returned from get_vlc().
+
+	'xxx_wrap' : give the number of bytes between each entry of the
+	'bits' or 'codes' tables.
+
+	'xxx_size' : gives the number of bytes of each entry of the 'bits'
+	or 'codes' tables.
+
+	'wrap' and 'size' make it possible to use any memory configuration and types
+	(byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
+
+	'useStatic' should be set to 1 for tables, which should be freed
+	with av_free_static(), 0 if freeVlc() will be used.
+	*/
+	int init_vlc(int nbBits, int nbCodes, const void *bits, int bitsWrap,
+		int bitsSize, const void *codes, int codesWrap, int codesSize,
+		const void *symbols, int symbolsWrap, int symbolsSize, int flags);
+
+	int init_vlc(int nbBits, int nbCodes, const void *bits, int bitsWrap, int bitsSize,
+		const void *codes, int codesWrap, int codesSize, int flags);
+
+	/**
+	 * Free VLC data
+	 */
+	void freeVlc();
+
+
+	/**
+	 * Build VLC decoding tables suitable for use with get_vlc().
+	 *
+	 * @param tableNbBits    max length of vlc codes to store directly in this table
+	 *                       (Longer codes are delegated to subtables.)
+	 *
+	 * @param nbCodes        number of elements in codes[]
+	 *
+	 * @param codes          descriptions of the vlc codes
+	 *                       These must be ordered such that codes going into the same subtable are contiguous.
+	 *                       Sorting by VLCcode.code is sufficient, though not necessary.
+	 */
+	int buildTable(int tableNbBits, int nbCodes, VLCcode *codes, int flags);
+
+	int allocTable(int size, int useStatic);
+};
+
+} // End of namespace Indeo
+} // End of namespace Image
+
+#endif