6f4d424f46
Rework the conversion of floats to decimal strings so it aligns precisely with the conversion of strings to floats in parsenum.c. This is to avoid rendering 1eX as 9.99999eX-1 etc. This is achieved by removing the power- of-10 tables and using pow() to compute the exponent directly, and that's done efficiently by first estimating the power-of-10 exponent from the power-of-2 exponent in the floating-point representation. Code size is reduced by roughly 100 to 200 bytes by this commit. Signed-off-by: Dan Ellis <dan.ellis@gmail.com>
19 lines
594 B
Python
19 lines
594 B
Python
# Test formatting of very large ints.
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# Relies on double-precision floats.
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import array
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import sys
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# Challenging way to express 1e200 and 1e100.
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print("{:.12e}".format(float("9" * 400 + "e-200")))
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print("{:.12e}".format(float("9" * 400 + "e-300")))
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# These correspond to the binary representation of 1e200 in float64s:
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v1 = 0x54B249AD2594C37D # 1e100
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v2 = 0x6974E718D7D7625A # 1e200
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print("{:.12e}".format(array.array("d", v1.to_bytes(8, sys.byteorder))[0]))
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print("{:.12e}".format(array.array("d", v2.to_bytes(8, sys.byteorder))[0]))
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for i in range(300):
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print(float("1e" + str(i)))
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