From eabdabb9822ed028cd8aeed94ded784b6364ba78 Mon Sep 17 00:00:00 2001 From: Umair Khan Date: Fri, 12 Aug 2016 17:49:15 +0530 Subject: avcodec: Implement masked lz decompression Signed-off-by: Umair Khan --- libavcodec/mlz.h | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 libavcodec/mlz.h (limited to 'libavcodec/mlz.h') diff --git a/libavcodec/mlz.h b/libavcodec/mlz.h new file mode 100644 index 0000000000..158715e7ec --- /dev/null +++ b/libavcodec/mlz.h @@ -0,0 +1,70 @@ +/* + * Copyright (c) 2016 Umair Khan + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVCODEC_MLZ_H +#define AVCODEC_MLZ_H + +#include "get_bits.h" + +#define CODE_UNSET -1 +#define CODE_BIT_INIT 9 +#define DIC_INDEX_INIT 512 // 2^9 +#define DIC_INDEX_MAX 32768l // 2^15 +#define FLUSH_CODE 256 +#define FREEZE_CODE 257 +#define FIRST_CODE 258 +#define MAX_CODE 32767l +#define TABLE_SIZE 35023l // TABLE_SIZE must be a prime number + +/** Dictionary structure for mlz decompression + */ +typedef struct MLZDict { + int string_code; + int parent_code; + int char_code; + int match_len; +} MLZDict; + +/** MLZ data strucure + */ +typedef struct MLZ { + int dic_code_bit; + int current_dic_index_max; + unsigned int bump_code; + unsigned int flush_code; + int next_code; + int freeze_flag; + MLZDict* dict; + void* context; +} MLZ; + +/** Initialize the dictionary + */ +void ff_mlz_init_dict(void* context, MLZ *mlz); + +/** Flush the dictionary + */ +void ff_mlz_flush_dict(MLZ *dict); + +/** Run mlz decompression on the next size bits and the output will be stored in buff + */ +int ff_mlz_decompression(MLZ* mlz, GetBitContext* gb, int size, unsigned char *buff); + +#endif /*AVCODEC_MLZ_H*/ -- cgit v1.2.3