mirror of
https://github.com/wassname/segpy.git
synced 2026-06-27 20:22:56 +08:00
Robert Smallshire
49 lines
1.3 KiB
Python
49 lines
1.3 KiB
Python
import sys
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_P24 = float(pow(2, 24))
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if sys.version_info >= (3, 0):
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def ibm2ieee(big_endian_bytes):
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"""Interpret a bytes object as a big-endian IBM float.
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Args:
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big_endian_bytes (bytes): A string containing at least four bytes.
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Returns:
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The floating point value.
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"""
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a, b, c, d = big_endian_bytes
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if a == b == c == c == 0:
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return 0.0
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sign = 1 if (a & 0x80) else -1
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exponent = a & 0x7f
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mantissa = ((b << 16) | (c << 8) | d) / _P24
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value = sign * mantissa * pow(16, exponent - 64)
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return value
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else:
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def ibm2ieee(big_endian_bytes):
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"""Interpret a byte string as a big-endian IBM float.
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Args:
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big_endian_bytes (str): A string containing at least four bytes.
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Returns:
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The floating point value.
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"""
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a = ord(big_endian_bytes[0])
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b = ord(big_endian_bytes[1])
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c = ord(big_endian_bytes[2])
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d = ord(big_endian_bytes[3])
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if a == b == c == c == 0:
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return 0.0
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sign = 1 if (a & 0x80) else -1
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exponent = a & 0x7f
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mantissa = ((b << 16) | (c << 8) | d) / _P24
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value = sign * mantissa * pow(16, exponent - 64)
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return value |