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50 lines
1.2 KiB
Python
50 lines
1.2 KiB
Python
# Miscellaneous utilities, meant to be included from build.py
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import os
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# Do a fork/execl because that way all children get the same stdout,
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# i.e. if it's a tty the executed program should behave appropriately.
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# Python probably has an idiomatic way to do this, but frankly idc.
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def run_sync(program: str, *args):
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path = os.popen("which " + program).read().strip()
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child = os.fork()
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if child == 0:
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os.execl(path, program, *args)
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print("execl() failed")
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exit(1)
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elif child == -1:
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print("fork() failed")
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exit(1)
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status = os.waitpid(child, 0)
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if status[1] != 0:
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print(program + " exited with status code " + str(status[1]))
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exit(1)
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def generate_crc_tab(poly_reverse: int):
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tab = []
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for crc in range(256):
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for _ in range(8):
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lsb = crc % 2
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crc >>= 1
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if lsb == 1:
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crc ^= poly_reverse
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tab.append(crc)
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return tab
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def do_crc(data, table):
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crc = 0xffffffff
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for byte in data:
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crc = (crc >> 8) ^ table[(crc ^ byte) & 0xff]
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return ~crc & 0xffffffff
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CCITT32_TAB = generate_crc_tab(0xedb88320)
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def crc32(data: bytes):
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global CCITT32_TAB
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return do_crc(data, CCITT32_TAB)
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