cpython/Lib/sunaudio.py

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"""Interpret sun audio headers."""
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MAGIC = b'.snd'
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class error(Exception):
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pass
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def get_long_be(s):
"""Convert a 4-byte value to integer."""
return (s[0]<<24) | (s[1]<<16) | (s[2]<<8) | s[3]
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def gethdr(fp):
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"""Read a sound header from an open file."""
if fp.read(4) != MAGIC:
raise error, 'gethdr: bad magic word'
hdr_size = get_long_be(fp.read(4))
data_size = get_long_be(fp.read(4))
encoding = get_long_be(fp.read(4))
sample_rate = get_long_be(fp.read(4))
channels = get_long_be(fp.read(4))
excess = hdr_size - 24
if excess < 0:
raise error, 'gethdr: bad hdr_size'
if excess > 0:
info = fp.read(excess)
else:
info = b''
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return (data_size, encoding, sample_rate, channels, info)
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def printhdr(file):
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"""Read and print the sound header of a named file."""
f = open(file, 'rb')
try:
hdr = gethdr(f)
finally:
f.close()
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data_size, encoding, sample_rate, channels, info = hdr
while info.endswith(b'\0'):
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info = info[:-1]
print('File name: ', file)
print('Data size: ', data_size)
print('Encoding: ', encoding)
print('Sample rate:', sample_rate)
print('Channels: ', channels)
print('Info: ', repr(info))