mirror of
https://github.com/python/cpython.git
synced 2026-06-22 11:03:15 -04:00
Serhiy Storchaka
ae62b53928
It was used to generate the _expat_decoding_table attribute of CodecInfo.
108 lines
3.0 KiB
Python
108 lines
3.0 KiB
Python
import sys
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def info(msg, *args):
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print(msg % args, file=sys.stderr)
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def fail(msg, *args):
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info(msg, *args)
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sys.exit(2)
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# ASCII characters that can appear in a well-formed XML document
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# except the characters "$@\^`{}~".
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compulsory_chars = (set(b'\t\n\r') | set(range(32, 127))) - set(br'$@\^`{}~')
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def check_compatibility(encoding):
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for i in compulsory_chars:
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c = chr(i)
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b = bytes([i])
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try:
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decoded = b.decode(encoding)
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except UnicodeDecodeError:
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info('Cannot decode byte %#04x (%a)', i, c)
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return False
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if decoded != c:
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info('Incompatible encoding: %#04x (%a) -> %a', i, c, decoded)
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return False
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return True
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def create_table(encoding):
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mapping = [-1] * 256
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non_bmp = None
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for i in range(0x110000):
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char = chr(i)
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try:
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encoded = char.encode(encoding)
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except UnicodeEncodeError:
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continue
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if i >= 0x10000 and non_bmp is None:
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non_bmp = i
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info('Non-BMP character: %r (U+%04X)', char, i)
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length = len(encoded)
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k = encoded[0]
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v = mapping[k]
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if length == 1:
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if v == -1:
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mapping[k] = i
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elif v < 0:
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fail('Ambiguous mapping for %#04x: '
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'%r (U+%04X) and %d-byte sequence',
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k, c, i, -v)
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else:
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info('Ambiguous mapping for %#04x: '
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'%r (U+%04X) and %r (U+%04X)',
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k, chr(v), v, char, i)
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else:
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if length > 4:
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fail('Too long encoding for %r (U+%04X): %r',
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char, i, encoded)
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if v == -1:
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mapping[k] = -length
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elif v != -length:
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if v < 0:
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fail('Ambiguous mapping for %#04x: '
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'%d-byte sequence and %d-byte sequence %r',
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k, -v, length, encoded)
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else:
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fail('Ambiguous mapping for %#04x: '
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'%r (U+%04X) and %d-byte sequence %r',
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k, chr(v), v, length, encoded)
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return mapping
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def print_table(mapping):
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print(' '*8 + '_expat_decoding_table=(', end='')
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if mapping[:128] == list(range(128)):
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print('*range(128),')
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start = 128
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else:
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print()
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start = 0
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line = ''
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pos = 0
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i = start
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while True:
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if i % 8 == 0:
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if len(line) > 68:
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print(' '*12 + line[:pos].rstrip())
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line = line[pos:]
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pos = len(line)
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if i == 256:
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break
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v = mapping[i]
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if v >= 0:
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v = hex(v)
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line += f'{v}, '
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i += 1
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print(' '*12 + line.rstrip().rstrip(',') + '),')
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encoding = sys.argv[1]
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if not check_compatibility(encoding):
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print(' '*8 + '_expat_decoding_table=False,')
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sys.exit(1)
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mapping = create_table(encoding)
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print_table(mapping)
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