Coverage for python/lsst/sphgeom/_yaml.py : 64%

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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/>.
22"""Add support for YAML serialization of regions."""
24__all__ = ()
26import yaml
27from ._sphgeom import (
28 Box,
29 Circle,
30 ConvexPolygon,
31 Ellipse,
32 HtmPixelization,
33 Mq3cPixelization,
34 Region,
35 Q3cPixelization,
36)
38YamlLoaders = (yaml.Loader, yaml.CLoader, yaml.FullLoader, yaml.SafeLoader, yaml.UnsafeLoader)
41# Regions
43def region_representer(dumper, data):
44 """Represent a sphgeom region object in a form suitable for YAML.
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()})
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)
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)
67 for loader in YamlLoaders:
68 yaml.add_constructor(f"lsst.sphgeom.{region_class.__name__}", region_constructor, Loader=loader)
71# Pixelization schemes
73def pixel_representer(dumper, data):
74 """Represent a pixelization in YAML
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()})
83def pixel_constructor(loader, node):
84 """Construct a pixelization object from YAML.
85 """
86 mapping = loader.construct_mapping(node)
88 className = node.tag
89 pixelMap = {"lsst.sphgeom.Q3cPixelization": Q3cPixelization,
90 "lsst.sphgeom.Mq3cPixelization": Mq3cPixelization,
91 "lsst.sphgeom.HtmPixelization": HtmPixelization,
92 }
94 if className not in pixelMap:
95 raise RuntimeError(f"Encountered unexpected class {className} associated with"
96 " sphgeom pixelization YAML constructor")
98 return pixelMap[className](mapping["level"])
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)