1  /**
       2   * \file        lzma/delta.h
       3   * \brief       Delta filter
       4   * \note        Never include this file directly. Use <lzma.h> instead.
       5   */
       6  
       7  /*
       8   * Author: Lasse Collin
       9   *
      10   * This file has been put into the public domain.
      11   * You can do whatever you want with this file.
      12   */
      13  
      14  #ifndef LZMA_H_INTERNAL
      15  #	error Never include this file directly. Use <lzma.h> instead.
      16  #endif
      17  
      18  
      19  /**
      20   * \brief       Filter ID
      21   *
      22   * Filter ID of the Delta filter. This is used as lzma_filter.id.
      23   */
      24  #define LZMA_FILTER_DELTA       LZMA_VLI_C(0x03)
      25  
      26  
      27  /**
      28   * \brief       Type of the delta calculation
      29   *
      30   * Currently only byte-wise delta is supported. Other possible types could
      31   * be, for example, delta of 16/32/64-bit little/big endian integers, but
      32   * these are not currently planned since byte-wise delta is almost as good.
      33   */
      34  typedef enum {
      35  	LZMA_DELTA_TYPE_BYTE
      36  } lzma_delta_type;
      37  
      38  
      39  /**
      40   * \brief       Options for the Delta filter
      41   *
      42   * These options are needed by both encoder and decoder.
      43   */
      44  typedef struct {
      45  	/** For now, this must always be LZMA_DELTA_TYPE_BYTE. */
      46  	lzma_delta_type type;
      47  
      48  	/**
      49  	 * \brief       Delta distance
      50  	 *
      51  	 * With the only currently supported type, LZMA_DELTA_TYPE_BYTE,
      52  	 * the distance is as bytes.
      53  	 *
      54  	 * Examples:
      55  	 *  - 16-bit stereo audio: distance = 4 bytes
      56  	 *  - 24-bit RGB image data: distance = 3 bytes
      57  	 */
      58  	uint32_t dist;
      59  
      60  	/**
      61  	 * \brief       Minimum value for lzma_options_delta.dist.
      62  	 */
      63  #	define LZMA_DELTA_DIST_MIN 1
      64  
      65  	/**
      66  	 * \brief       Maximum value for lzma_options_delta.dist.
      67  	 */
      68  #	define LZMA_DELTA_DIST_MAX 256
      69  
      70  	/*
      71  	 * Reserved space to allow possible future extensions without
      72  	 * breaking the ABI. You should not touch these, because the names
      73  	 * of these variables may change. These are and will never be used
      74  	 * when type is LZMA_DELTA_TYPE_BYTE, so it is safe to leave these
      75  	 * uninitialized.
      76  	 */
      77  
      78  	/** \private     Reserved member. */
      79  	uint32_t reserved_int1;
      80  
      81  	/** \private     Reserved member. */
      82  	uint32_t reserved_int2;
      83  
      84  	/** \private     Reserved member. */
      85  	uint32_t reserved_int3;
      86  
      87  	/** \private     Reserved member. */
      88  	uint32_t reserved_int4;
      89  
      90  	/** \private     Reserved member. */
      91  	void *reserved_ptr1;
      92  
      93  	/** \private     Reserved member. */
      94  	void *reserved_ptr2;
      95  
      96  } lzma_options_delta;