avcodec: Implement masked lz decompression

Signed-off-by: Umair Khan <omerjerk@gmail.com>

1 files changed, 70 insertions, 0 deletions

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 <omerjerk@gmail.com>
+ *
+ * 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*/