root / lab4 / .minix-src / include / lzma / delta.h @ 13
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1 | 13 | up20180614 | /**
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2 | * \file lzma/delta.h
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3 | * \brief Delta filter
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4 | */
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5 | |||
6 | /*
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7 | * Author: Lasse Collin
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8 | *
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9 | * This file has been put into the public domain.
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10 | * You can do whatever you want with this file.
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11 | *
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12 | * See ../lzma.h for information about liblzma as a whole.
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13 | */
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14 | |||
15 | #ifndef LZMA_H_INTERNAL
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16 | # error Never include this file directly. Use <lzma.h> instead.
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17 | #endif
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18 | |||
19 | |||
20 | /**
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21 | * \brief Filter ID
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22 | *
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23 | * Filter ID of the Delta filter. This is used as lzma_filter.id.
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24 | */
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25 | #define LZMA_FILTER_DELTA LZMA_VLI_C(0x03) |
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26 | |||
27 | |||
28 | /**
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29 | * \brief Type of the delta calculation
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30 | *
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31 | * Currently only byte-wise delta is supported. Other possible types could
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32 | * be, for example, delta of 16/32/64-bit little/big endian integers, but
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33 | * these are not currently planned since byte-wise delta is almost as good.
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34 | */
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35 | typedef enum { |
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36 | LZMA_DELTA_TYPE_BYTE |
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37 | } lzma_delta_type; |
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38 | |||
39 | |||
40 | /**
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41 | * \brief Options for the Delta filter
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42 | *
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43 | * These options are needed by both encoder and decoder.
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44 | */
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45 | typedef struct { |
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46 | /** For now, this must always be LZMA_DELTA_TYPE_BYTE. */
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47 | lzma_delta_type type; |
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48 | |||
49 | /**
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50 | * \brief Delta distance
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51 | *
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52 | * With the only currently supported type, LZMA_DELTA_TYPE_BYTE,
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53 | * the distance is as bytes.
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54 | *
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55 | * Examples:
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56 | * - 16-bit stereo audio: distance = 4 bytes
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57 | * - 24-bit RGB image data: distance = 3 bytes
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58 | */
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59 | uint32_t dist; |
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60 | # define LZMA_DELTA_DIST_MIN 1 |
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61 | # define LZMA_DELTA_DIST_MAX 256 |
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62 | |||
63 | /*
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64 | * Reserved space to allow possible future extensions without
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65 | * breaking the ABI. You should not touch these, because the names
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66 | * of these variables may change. These are and will never be used
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67 | * when type is LZMA_DELTA_TYPE_BYTE, so it is safe to leave these
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68 | * uninitialized.
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69 | */
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70 | uint32_t reserved_int1; |
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71 | uint32_t reserved_int2; |
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72 | uint32_t reserved_int3; |
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73 | uint32_t reserved_int4; |
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74 | void *reserved_ptr1;
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75 | void *reserved_ptr2;
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76 | |||
77 | } lzma_options_delta; |