Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/PIL/FitsImagePlugin.py: 18%

1# 

2# The Python Imaging Library 

3# $Id$ 

4# 

5# FITS file handling 

6# 

7# Copyright (c) 1998-2003 by Fredrik Lundh 

8# 

9# See the README file for information on usage and redistribution. 

10# 

11from __future__ import annotations 

12 

13import gzip 

14import math 

15 

16from . import Image, ImageFile 

17 

18 

19def _accept(prefix: bytes) -> bool: 

20 return prefix.startswith(b"SIMPLE") 

21 

22 

23class FitsImageFile(ImageFile.ImageFile): 

24 format = "FITS" 

25 format_description = "FITS" 

26 

27 def _open(self) -> None: 

28 assert self.fp is not None 

29 

30 headers: dict[bytes, bytes] = {} 

31 header_in_progress = False 

32 decoder_name = "" 

33 while True: 

34 header = self.fp.read(80) 

35 if not header: 

36 msg = "Truncated FITS file" 

37 raise OSError(msg) 

38 keyword = header[:8].strip() 

39 if keyword in (b"SIMPLE", b"XTENSION"): 

40 header_in_progress = True 

41 elif headers and not header_in_progress: 

42 # This is now a data unit 

43 break 

44 elif keyword == b"END": 

45 # Seek to the end of the header unit 

46 self.fp.seek(math.ceil(self.fp.tell() / 2880) * 2880) 

47 if not decoder_name: 

48 decoder_name, offset, args = self._parse_headers(headers) 

49 

50 header_in_progress = False 

51 continue 

52 

53 if decoder_name: 

54 # Keep going to read past the headers 

55 continue 

56 

57 value = header[8:].split(b"/")[0].strip() 

58 if value.startswith(b"="): 

59 value = value[1:].strip() 

60 if not headers and (not _accept(keyword) or value != b"T"): 

61 msg = "Not a FITS file" 

62 raise SyntaxError(msg) 

63 headers[keyword] = value 

64 

65 if not decoder_name: 

66 msg = "No image data" 

67 raise ValueError(msg) 

68 

69 offset += self.fp.tell() - 80 

70 self.tile = [ImageFile._Tile(decoder_name, (0, 0) + self.size, offset, args)] 

71 

72 def _get_size( 

73 self, headers: dict[bytes, bytes], prefix: bytes 

74 ) -> tuple[int, int] | None: 

75 naxis = int(headers[prefix + b"NAXIS"]) 

76 if naxis == 0: 

77 return None 

78 

79 if naxis == 1: 

80 return 1, int(headers[prefix + b"NAXIS1"]) 

81 else: 

82 return int(headers[prefix + b"NAXIS1"]), int(headers[prefix + b"NAXIS2"]) 

83 

84 def _parse_headers( 

85 self, headers: dict[bytes, bytes] 

86 ) -> tuple[str, int, tuple[str | int, ...]]: 

87 prefix = b"" 

88 decoder_name = "raw" 

89 offset = 0 

90 if ( 

91 headers.get(b"XTENSION") == b"'BINTABLE'" 

92 and headers.get(b"ZIMAGE") == b"T" 

93 and headers[b"ZCMPTYPE"] == b"'GZIP_1 '" 

94 ): 

95 no_prefix_size = self._get_size(headers, prefix) or (0, 0) 

96 number_of_bits = int(headers[b"BITPIX"]) 

97 offset = no_prefix_size[0] * no_prefix_size[1] * (number_of_bits // 8) 

98 

99 prefix = b"Z" 

100 decoder_name = "fits_gzip" 

101 

102 size = self._get_size(headers, prefix) 

103 if not size: 

104 return "", 0, () 

105 

106 self._size = size 

107 

108 number_of_bits = int(headers[prefix + b"BITPIX"]) 

109 if number_of_bits == 8: 

110 self._mode = "L" 

111 elif number_of_bits == 16: 

112 self._mode = "I;16" 

113 elif number_of_bits == 32: 

114 self._mode = "I" 

115 elif number_of_bits in (-32, -64): 

116 self._mode = "F" 

117 

118 args: tuple[str | int, ...] 

119 if decoder_name == "raw": 

120 args = (self.mode, 0, -1) 

121 else: 

122 args = (number_of_bits,) 

123 return decoder_name, offset, args 

124 

125 

126class FitsGzipDecoder(ImageFile.PyDecoder): 

127 _pulls_fd = True 

128 

129 def decode(self, buffer: bytes | Image.SupportsArrayInterface) -> tuple[int, int]: 

130 assert self.fd is not None 

131 value = gzip.decompress(self.fd.read()) 

132 

133 rows = [] 

134 offset = 0 

135 number_of_bits = min(self.args[0] // 8, 4) 

136 for y in range(self.state.ysize): 

137 row = bytearray() 

138 for x in range(self.state.xsize): 

139 row += value[offset + (4 - number_of_bits) : offset + 4] 

140 offset += 4 

141 rows.append(row) 

142 self.set_as_raw(bytes([pixel for row in rows[::-1] for pixel in row])) 

143 return -1, 0 

144 

145 

146# -------------------------------------------------------------------- 

147# Registry 

148 

149Image.register_open(FitsImageFile.format, FitsImageFile, _accept) 

150Image.register_decoder("fits_gzip", FitsGzipDecoder) 

151 

152Image.register_extensions(FitsImageFile.format, [".fit", ".fits"])