Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/h5py/_hl/selections2.py: 21%

1# This file is part of h5py, a Python interface to the HDF5 library. 

2# 

3# http://www.h5py.org 

4# 

5# Copyright 2008-2013 Andrew Collette and contributors 

6# 

7# License: Standard 3-clause BSD; see "license.txt" for full license terms 

8# and contributor agreement. 

9 

10""" 

11 Implements a portion of the selection operations. 

12""" 

13 

14import numpy as np 

15from .. import h5s 

16 

17def read_dtypes(dataset_dtype, names): 

18 """ Returns a 2-tuple containing: 

19 

20 1. Output dataset dtype 

21 2. Dtype containing HDF5-appropriate description of destination 

22 """ 

23 

24 if len(names) == 0: # Not compound, or all fields needed 

25 format_dtype = dataset_dtype 

26 

27 elif dataset_dtype.names is None: 

28 raise ValueError("Field names only allowed for compound types") 

29 

30 elif any(x not in dataset_dtype.names for x in names): 

31 raise ValueError("Field does not appear in this type.") 

32 

33 else: 

34 format_dtype = np.dtype([(name, dataset_dtype.fields[name][0]) for name in names]) 

35 

36 if len(names) == 1: 

37 # We don't preserve the field information if only one explicitly selected. 

38 output_dtype = format_dtype.fields[names[0]][0] 

39 

40 else: 

41 output_dtype = format_dtype 

42 

43 return output_dtype, format_dtype 

44 

45 

46def read_selections_scalar(dsid, args): 

47 """ Returns a 2-tuple containing: 

48 

49 1. Output dataset shape 

50 2. HDF5 dataspace containing source selection. 

51 

52 Works for scalar datasets. 

53 """ 

54 

55 if dsid.shape != (): 

56 raise RuntimeError("Illegal selection function for non-scalar dataset") 

57 

58 if args == (): 

59 # This is a signal that an array scalar should be returned instead 

60 # of an ndarray with shape () 

61 out_shape = None 

62 

63 elif args == (Ellipsis,): 

64 out_shape = () 

65 

66 else: 

67 raise ValueError("Illegal slicing argument for scalar dataspace") 

68 

69 source_space = dsid.get_space() 

70 source_space.select_all() 

71 

72 return out_shape, source_space 

73 

74class ScalarReadSelection: 

75 

76 """ 

77 Implements slicing for scalar datasets. 

78 """ 

79 

80 def __init__(self, fspace, args): 

81 if args == (): 

82 self.mshape = None 

83 elif args == (Ellipsis,): 

84 self.mshape = () 

85 else: 

86 raise ValueError("Illegal slicing argument for scalar dataspace") 

87 

88 self.mspace = h5s.create(h5s.SCALAR) 

89 self.fspace = fspace 

90 

91 def __iter__(self): 

92 self.mspace.select_all() 

93 yield self.fspace, self.mspace 

94 

95def select_read(fspace, args): 

96 """ Top-level dispatch function for reading. 

97 

98 At the moment, only supports reading from scalar datasets. 

99 """ 

100 if fspace.shape == (): 

101 return ScalarReadSelection(fspace, args) 

102 

103 raise NotImplementedError()