97 lines
2.4 KiB
Python
97 lines
2.4 KiB
Python
# (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
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# and is covered by GPLv3 license found in COPYING.
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#
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# utils.py - Misc utils. My favourite kind of source file.
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#
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import gc, sys
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class imported:
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# Context manager that temporarily imports
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# a list of modules.
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# LATER: doubtful this saves any memory when all the code is frozen.
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def __init__(self, *modules):
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self.modules = modules
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def __enter__(self):
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# import everything required
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rv = tuple(__import__(n) for n in self.modules)
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return rv[0] if len(self.modules) == 1 else rv
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def __exit__(self, exc_type, exc_value, traceback):
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for n in self.modules:
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if n in sys.modules:
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del sys.modules[n]
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# recovery that tasty memory.
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gc.collect()
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# class min_dramatic_pause:
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# # insure that something takes at least N ms
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# def __init__(self, min_time):
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# import utime
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#
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# self.min_time = min_time
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# self.start_time = utime.ticks_ms()
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#
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# def __enter__(self):
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# pass
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#
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# def __exit__(self, exc_type, exc_value, traceback):
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# import utime
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#
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# if exc_type is not None: return
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#
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# actual = utime.ticks_ms() - self.start_time
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# if actual < self.min_time:
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# utime.sleep_ms(self.min_time - actual)
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#
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def pretty_delay(n):
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# decode # of seconds into various ranges, need not be precise.
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if n < 120:
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return '%d seconds' % n
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n /= 60
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if n < 60:
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return '%d minutes' % n
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n /= 60
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if n < 48:
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return '%.1f hours' % n
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n /= 24
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return 'about %d days' % n
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def pop_count(i):
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# 32-bit population count for integers
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# from <https://stackoverflow.com/questions/9829578>
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i = i - ((i >> 1) & 0x55555555)
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i = (i & 0x33333333) + ((i >> 2) & 0x33333333)
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return (((i + (i >> 4) & 0xF0F0F0F) * 0x1010101) & 0xffffffff) >> 24
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def get_filesize(fn):
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# like os.path.getsize()
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import uos
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return uos.stat(fn)[6]
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class HexWriter:
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# Emulate a file/stream but convert binary to hex as they write
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def __init__(self, fd):
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self.fd = fd
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def __enter__(self):
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self.fd.__enter__()
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return self
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def __exit__(self, *a, **k):
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self.fd.write('\r\n')
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return self.fd.__exit__(*a, **k)
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def write(self, b):
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for ch in b:
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self.fd.write('%02x' % ch)
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# EOF
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