Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/pyzstd/_c/__init__.py: 88%

1from collections import namedtuple 

2from enum import IntEnum 

3 

4from ._zstd import ( 

5 EndlessZstdDecompressor, 

6 PYZSTD_CONFIG, 

7 RichMemZstdCompressor, 

8 ZstdCompressor, 

9 ZstdDecompressor, 

10 ZstdDict, 

11 ZstdError, 

12 ZstdFileReader, 

13 ZstdFileWriter, 

14 _ZSTD_CStreamSizes, 

15 _ZSTD_DStreamSizes, 

16 _ZSTD_btlazy2, 

17 _ZSTD_btopt, 

18 _ZSTD_btultra, 

19 _ZSTD_btultra2, 

20 _ZSTD_c_chainLog, 

21 _ZSTD_c_checksumFlag, 

22 _ZSTD_c_compressionLevel, 

23 _ZSTD_c_contentSizeFlag, 

24 _ZSTD_c_dictIDFlag, 

25 _ZSTD_c_enableLongDistanceMatching, 

26 _ZSTD_c_hashLog, 

27 _ZSTD_c_jobSize, 

28 _ZSTD_c_ldmBucketSizeLog, 

29 _ZSTD_c_ldmHashLog, 

30 _ZSTD_c_ldmHashRateLog, 

31 _ZSTD_c_ldmMinMatch, 

32 _ZSTD_c_minMatch, 

33 _ZSTD_c_nbWorkers, 

34 _ZSTD_c_overlapLog, 

35 _ZSTD_c_searchLog, 

36 _ZSTD_c_strategy, 

37 _ZSTD_c_targetCBlockSize, 

38 _ZSTD_c_targetLength, 

39 _ZSTD_c_windowLog, 

40 _ZSTD_d_windowLogMax, 

41 _ZSTD_dfast, 

42 _ZSTD_fast, 

43 _ZSTD_greedy, 

44 _ZSTD_lazy, 

45 _ZSTD_lazy2, 

46 _compressionLevel_values, 

47 _finalize_dict, 

48 _get_frame_info, 

49 _get_param_bounds, 

50 _set_parameter_types, 

51 _train_dict, 

52 compress_stream, 

53 decompress, 

54 decompress_stream, 

55 get_frame_size, 

56 zstd_version, 

57 zstd_version_info 

58) 

59 

60__all__ = (# From this file 

61 'compressionLevel_values', 'get_frame_info', 

62 'CParameter', 'DParameter', 'Strategy', 

63 # From _zstd 

64 'ZstdCompressor', 'RichMemZstdCompressor', 

65 'ZstdDecompressor', 'EndlessZstdDecompressor', 

66 'ZstdDict', 'ZstdError', 'decompress', 'get_frame_size', 

67 'compress_stream', 'decompress_stream', 

68 'zstd_version', 'zstd_version_info', 

69 '_train_dict', '_finalize_dict', 

70 'ZstdFileReader', 'ZstdFileWriter', 

71 '_ZSTD_CStreamSizes', '_ZSTD_DStreamSizes', 

72 'PYZSTD_CONFIG') 

73 

74 

75# compressionLevel_values 

76_nt_values = namedtuple('values', ['default', 'min', 'max']) 

77compressionLevel_values = _nt_values(*_compressionLevel_values) 

78 

79 

80_nt_frame_info = namedtuple('frame_info', 

81 ['decompressed_size', 'dictionary_id']) 

82 

83def get_frame_info(frame_buffer): 

84 """Get zstd frame information from a frame header. 

85 

86 Parameter 

87 frame_buffer: A bytes-like object. It should starts from the beginning of 

88 a frame, and needs to include at least the frame header (6 to 

89 18 bytes). 

90 

91 Return a two-items namedtuple: (decompressed_size, dictionary_id) 

92 

93 If decompressed_size is None, decompressed size is unknown. 

94 

95 dictionary_id is a 32-bit unsigned integer value. 0 means dictionary ID was 

96 not recorded in the frame header, the frame may or may not need a dictionary 

97 to be decoded, and the ID of such a dictionary is not specified. 

98 

99 It's possible to append more items to the namedtuple in the future.""" 

100 

101 ret_tuple = _get_frame_info(frame_buffer) 

102 return _nt_frame_info(*ret_tuple) 

103 

104 

105class _UnsupportedCParameter: 

106 def __set_name__(self, _, name): 

107 self.name = name 

108 

109 def __get__(self, *_, **__): 

110 msg = ("%s CParameter only available when the underlying " 

111 "zstd library's version is greater than or equal to v1.5.6. " 

112 "At pyzstd module's run-time, zstd version is %s.") % \ 

113 (self.name, zstd_version) 

114 raise NotImplementedError(msg) 

115 

116 

117class CParameter(IntEnum): 

118 """Compression parameters""" 

119 

120 compressionLevel = _ZSTD_c_compressionLevel 

121 windowLog = _ZSTD_c_windowLog 

122 hashLog = _ZSTD_c_hashLog 

123 chainLog = _ZSTD_c_chainLog 

124 searchLog = _ZSTD_c_searchLog 

125 minMatch = _ZSTD_c_minMatch 

126 targetLength = _ZSTD_c_targetLength 

127 strategy = _ZSTD_c_strategy 

128 if zstd_version_info >= (1, 5, 6): 

129 targetCBlockSize = _ZSTD_c_targetCBlockSize 

130 else: 

131 targetCBlockSize = _UnsupportedCParameter() 

132 

133 enableLongDistanceMatching = _ZSTD_c_enableLongDistanceMatching 

134 ldmHashLog = _ZSTD_c_ldmHashLog 

135 ldmMinMatch = _ZSTD_c_ldmMinMatch 

136 ldmBucketSizeLog = _ZSTD_c_ldmBucketSizeLog 

137 ldmHashRateLog = _ZSTD_c_ldmHashRateLog 

138 

139 contentSizeFlag = _ZSTD_c_contentSizeFlag 

140 checksumFlag = _ZSTD_c_checksumFlag 

141 dictIDFlag = _ZSTD_c_dictIDFlag 

142 

143 nbWorkers = _ZSTD_c_nbWorkers 

144 jobSize = _ZSTD_c_jobSize 

145 overlapLog = _ZSTD_c_overlapLog 

146 

147 def bounds(self): 

148 """Return lower and upper bounds of a compression parameter, both inclusive.""" 

149 # 1 means compression parameter 

150 return _get_param_bounds(1, self.value) 

151 

152 

153class DParameter(IntEnum): 

154 """Decompression parameters""" 

155 

156 windowLogMax = _ZSTD_d_windowLogMax 

157 

158 def bounds(self): 

159 """Return lower and upper bounds of a decompression parameter, both inclusive.""" 

160 # 0 means decompression parameter 

161 return _get_param_bounds(0, self.value) 

162 

163 

164class Strategy(IntEnum): 

165 """Compression strategies, listed from fastest to strongest. 

166 

167 Note : new strategies _might_ be added in the future, only the order 

168 (from fast to strong) is guaranteed. 

169 """ 

170 fast = _ZSTD_fast 

171 dfast = _ZSTD_dfast 

172 greedy = _ZSTD_greedy 

173 lazy = _ZSTD_lazy 

174 lazy2 = _ZSTD_lazy2 

175 btlazy2 = _ZSTD_btlazy2 

176 btopt = _ZSTD_btopt 

177 btultra = _ZSTD_btultra 

178 btultra2 = _ZSTD_btultra2 

179 

180 

181# Set CParameter/DParameter types for validity check 

182_set_parameter_types(CParameter, DParameter)