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