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1# This file is part of sphgeom. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (http://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This program is free software: you can redistribute it and/or modify 

10# it under the terms of the GNU General Public License as published by 

11# the Free Software Foundation, either version 3 of the License, or 

12# (at your option) any later version. 

13# 

14# This program is distributed in the hope that it will be useful, 

15# but WITHOUT ANY WARRANTY; without even the implied warranty of 

16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

17# GNU General Public License for more details. 

18# 

19# You should have received a copy of the GNU General Public License 

20# along with this program. If not, see <http://www.gnu.org/licenses/>. 

21 

22"""Add support for YAML serialization of regions.""" 

23 

24__all__ = () 

25 

26import yaml 

27from ._sphgeom import ( 

28 Box, 

29 Circle, 

30 ConvexPolygon, 

31 Ellipse, 

32 HtmPixelization, 

33 Mq3cPixelization, 

34 Region, 

35 Q3cPixelization, 

36) 

37 

38YamlLoaders = (yaml.Loader, yaml.CLoader, yaml.FullLoader, yaml.SafeLoader, yaml.UnsafeLoader) 

39 

40 

41# Regions 

42 

43def region_representer(dumper, data): 

44 """Represent a sphgeom region object in a form suitable for YAML. 

45 

46 Stores the region as a mapping with a single ``encoded`` key 

47 storing the hex encoded byte string. 

48 """ 

49 encoded = data.encode() 

50 return dumper.represent_mapping(f"lsst.sphgeom.{type(data).__name__}", 

51 {"encoded": encoded.hex()}) 

52 

53 

54def region_constructor(loader, node): 

55 """Construct a sphgeom region from YAML""" 

56 mapping = loader.construct_mapping(node) 

57 encoded = bytes.fromhex(mapping["encoded"]) 

58 # The generic Region base class can instantiate a region of the 

59 # correct type. 

60 return Region.decode(encoded) 

61 

62 

63# Register all the region classes with the same constructor and representer 

64for region_class in (ConvexPolygon, Ellipse, Circle, Box): 

65 yaml.add_representer(region_class, region_representer) 

66 

67 for loader in YamlLoaders: 

68 yaml.add_constructor(f"lsst.sphgeom.{region_class.__name__}", region_constructor, Loader=loader) 

69 

70 

71# Pixelization schemes 

72 

73def pixel_representer(dumper, data): 

74 """Represent a pixelization in YAML 

75 

76 Stored as the pixelization level in a mapping with a single key 

77 ``level``. 

78 """ 

79 return dumper.represent_mapping(f"lsst.sphgeom.{type(data).__name__}", 

80 {"level": data.getLevel()}) 

81 

82 

83def pixel_constructor(loader, node): 

84 """Construct a pixelization object from YAML. 

85 """ 

86 mapping = loader.construct_mapping(node) 

87 

88 className = node.tag 

89 pixelMap = {"lsst.sphgeom.Q3cPixelization": Q3cPixelization, 

90 "lsst.sphgeom.Mq3cPixelization": Mq3cPixelization, 

91 "lsst.sphgeom.HtmPixelization": HtmPixelization, 

92 } 

93 

94 if className not in pixelMap: 

95 raise RuntimeError(f"Encountered unexpected class {className} associated with" 

96 " sphgeom pixelization YAML constructor") 

97 

98 return pixelMap[className](mapping["level"]) 

99 

100 

101# All the pixelization schemes use the same approach with getLevel 

102for pixelSchemeCls in (HtmPixelization, Q3cPixelization, Mq3cPixelization): 

103 yaml.add_representer(pixelSchemeCls, pixel_representer) 

104 for loader in YamlLoaders: 

105 yaml.add_constructor(f"lsst.sphgeom.{pixelSchemeCls.__name__}", pixel_constructor, Loader=loader)