root / lab4 / .minix-src / include / lzma / check.h @ 13
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1 | 13 | up20180614 | /**
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2 | * \file lzma/check.h
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3 | * \brief Integrity checks
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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 Type of the integrity check (Check ID)
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22 | *
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23 | * The .xz format supports multiple types of checks that are calculated
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24 | * from the uncompressed data. They vary in both speed and ability to
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25 | * detect errors.
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26 | */
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27 | typedef enum { |
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28 | LZMA_CHECK_NONE = 0,
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29 | /**<
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30 | * No Check is calculated.
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31 | *
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32 | * Size of the Check field: 0 bytes
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33 | */
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34 | |||
35 | LZMA_CHECK_CRC32 = 1,
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36 | /**<
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37 | * CRC32 using the polynomial from the IEEE 802.3 standard
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38 | *
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39 | * Size of the Check field: 4 bytes
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40 | */
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41 | |||
42 | LZMA_CHECK_CRC64 = 4,
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43 | /**<
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44 | * CRC64 using the polynomial from the ECMA-182 standard
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45 | *
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46 | * Size of the Check field: 8 bytes
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47 | */
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48 | |||
49 | LZMA_CHECK_SHA256 = 10
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50 | /**<
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51 | * SHA-256
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52 | *
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53 | * Size of the Check field: 32 bytes
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54 | */
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55 | } lzma_check; |
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56 | |||
57 | |||
58 | /**
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59 | * \brief Maximum valid Check ID
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60 | *
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61 | * The .xz file format specification specifies 16 Check IDs (0-15). Some
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62 | * of them are only reserved, that is, no actual Check algorithm has been
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63 | * assigned. When decoding, liblzma still accepts unknown Check IDs for
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64 | * future compatibility. If a valid but unsupported Check ID is detected,
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65 | * liblzma can indicate a warning; see the flags LZMA_TELL_NO_CHECK,
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66 | * LZMA_TELL_UNSUPPORTED_CHECK, and LZMA_TELL_ANY_CHECK in container.h.
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67 | */
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68 | #define LZMA_CHECK_ID_MAX 15 |
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69 | |||
70 | |||
71 | /**
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72 | * \brief Test if the given Check ID is supported
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73 | *
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74 | * Return true if the given Check ID is supported by this liblzma build.
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75 | * Otherwise false is returned. It is safe to call this with a value that
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76 | * is not in the range [0, 15]; in that case the return value is always false.
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77 | *
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78 | * You can assume that LZMA_CHECK_NONE and LZMA_CHECK_CRC32 are always
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79 | * supported (even if liblzma is built with limited features).
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80 | */
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81 | extern LZMA_API(lzma_bool) lzma_check_is_supported(lzma_check check)
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82 | lzma_nothrow lzma_attr_const; |
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83 | |||
84 | |||
85 | /**
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86 | * \brief Get the size of the Check field with the given Check ID
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87 | *
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88 | * Although not all Check IDs have a check algorithm associated, the size of
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89 | * every Check is already frozen. This function returns the size (in bytes) of
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90 | * the Check field with the specified Check ID. The values are:
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91 | * { 0, 4, 4, 4, 8, 8, 8, 16, 16, 16, 32, 32, 32, 64, 64, 64 }
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92 | *
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93 | * If the argument is not in the range [0, 15], UINT32_MAX is returned.
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94 | */
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95 | extern LZMA_API(uint32_t) lzma_check_size(lzma_check check)
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96 | lzma_nothrow lzma_attr_const; |
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97 | |||
98 | |||
99 | /**
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100 | * \brief Maximum size of a Check field
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101 | */
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102 | #define LZMA_CHECK_SIZE_MAX 64 |
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103 | |||
104 | |||
105 | /**
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106 | * \brief Calculate CRC32
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107 | *
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108 | * Calculate CRC32 using the polynomial from the IEEE 802.3 standard.
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109 | *
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110 | * \param buf Pointer to the input buffer
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111 | * \param size Size of the input buffer
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112 | * \param crc Previously returned CRC value. This is used to
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113 | * calculate the CRC of a big buffer in smaller chunks.
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114 | * Set to zero when starting a new calculation.
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115 | *
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116 | * \return Updated CRC value, which can be passed to this function
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117 | * again to continue CRC calculation.
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118 | */
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119 | extern LZMA_API(uint32_t) lzma_crc32(
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120 | const uint8_t *buf, size_t size, uint32_t crc)
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121 | lzma_nothrow lzma_attr_pure; |
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122 | |||
123 | |||
124 | /**
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125 | * \brief Calculate CRC64
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126 | *
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127 | * Calculate CRC64 using the polynomial from the ECMA-182 standard.
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128 | *
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129 | * This function is used similarly to lzma_crc32(). See its documentation.
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130 | */
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131 | extern LZMA_API(uint64_t) lzma_crc64(
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132 | const uint8_t *buf, size_t size, uint64_t crc)
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133 | lzma_nothrow lzma_attr_pure; |
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134 | |||
135 | |||
136 | /*
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137 | * SHA-256 functions are currently not exported to public API.
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138 | * Contact Lasse Collin if you think it should be.
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139 | */
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140 | |||
141 | |||
142 | /**
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143 | * \brief Get the type of the integrity check
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144 | *
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145 | * This function can be called only immediately after lzma_code() has
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146 | * returned LZMA_NO_CHECK, LZMA_UNSUPPORTED_CHECK, or LZMA_GET_CHECK.
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147 | * Calling this function in any other situation has undefined behavior.
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148 | */
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149 | extern LZMA_API(lzma_check) lzma_get_check(const lzma_stream *strm) |
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150 | lzma_nothrow; |