chromium/third_party/ffmpeg/libavutil/lzo.c

/*
 * LZO 1x decompression
 * Copyright (c) 2006 Reimar Doeffinger
 *
 * 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
 */

#include <limits.h>
#include <stdint.h>
#include <string.h>

#include "avassert.h"
#include "intreadwrite.h"
#include "lzo.h"
#include "macros.h"
#include "mem.h"

/// Define if we may write up to 12 bytes beyond the output buffer.
#define OUTBUF_PADDED …
/// Define if we may read up to 8 bytes beyond the input buffer.
#define INBUF_PADDED …

LZOContext;

/**
 * @brief Reads one byte from the input buffer, avoiding an overrun.
 * @return byte read
 */
static inline int get_byte(LZOContext *c)
{ … }

#ifdef INBUF_PADDED
#define GETB(c) …
#else
#define GETB …
#endif

/**
 * @brief Decodes a length value in the coding used by lzo.
 * @param x previous byte value
 * @param mask bits used from x
 * @return decoded length value
 */
static inline int get_len(LZOContext *c, int x, int mask)
{ … }

/**
 * @brief Copies bytes from input to output buffer with checking.
 * @param cnt number of bytes to copy, must be >= 0
 */
static inline void copy(LZOContext *c, int cnt)
{ … }

/**
 * @brief Copies previously decoded bytes to current position.
 * @param back how many bytes back we start, must be > 0
 * @param cnt number of bytes to copy, must be > 0
 *
 * cnt > back is valid, this will copy the bytes we just copied,
 * thus creating a repeating pattern with a period length of back.
 */
static inline void copy_backptr(LZOContext *c, int back, int cnt)
{ … }

int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen)
{ … }