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 parse-bytecode

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float2int.py

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# check cases converting float to int, relying only on single precision float

try:

import ustruct as struct

except:

import struct

# work out configuration values

is_64bit = struct.calcsize("P") == 8

# 0 = none, 1 = long long, 2 = mpz

try:

dummy = 0x7fffffffffffffff

try:

if (0xffffffffffffffff + 1) > 0:

ll_type = 2

else:

ll_type = 1

except:

# in case the sum in the if statement above changes to raising an exception on overflow

ll_type = 1

except:

ll_type = 0

# basic conversion

print(int(14187745.))

print("%d" % 14187745.)

if ll_type == 2:

print(int(2.**100))

print("%d" % 2.**100)

testpass = True

p2_rng = ((30,63,127),(62,63,127))[is_64bit][ll_type]

for i in range(0,p2_rng):

bitcnt = len(bin(int(2.**i))) - 3;

if i != bitcnt:

print('fail: 2.**%u was %u bits long' % (i, bitcnt));

testpass = False

print("power of 2 test: %s" % (testpass and 'passed' or 'failed'))

# TODO why does 10**12 fail this test for single precision float?

testpass = True

p10_rng = 9 if (ll_type == 0 and ~is_64bit) else 11

for i in range(0,p10_rng):

digcnt = len(str(int(10.**i))) - 1;

if i != digcnt:

print('fail: 10.**%u was %u digits long' % (i, digcnt));

testpass = False

print("power of 10 test: %s" % (testpass and 'passed' or 'failed'))

def fp2int_test(num, name, should_fail):

try:

x = int(num)

passed = ~should_fail

except:

passed = should_fail

print('%s: %s' % (name, passed and 'passed' or 'failed'))

if ll_type != 2:

if ll_type == 0:

if is_64bit:

neg_bad_fp = -1.00000005*2.**62.

pos_bad_fp = 2.**62.

neg_good_fp = -2.**62.

pos_good_fp = 0.99999993*2.**62.

else:

neg_bad_fp = -1.00000005*2.**30.

pos_bad_fp = 2.**30.

neg_good_fp = -2.**30.

pos_good_fp = 0.9999999499*2.**30.

else:

neg_bad_fp = -0.51*2.**64.

pos_bad_fp = 2.**63.

neg_good_fp = -2.**63.

pos_good_fp = 1.9999998*2.**62.

fp2int_test(neg_bad_fp, 'neg bad', True)

fp2int_test(pos_bad_fp, 'pos bad', True)

fp2int_test(neg_good_fp, 'neg good', False)

fp2int_test(pos_good_fp, 'pos good', False)

else:

fp2int_test(-1.999999879*2.**127., 'large neg', False)

fp2int_test(1.999999879*2.**127., 'large pos', False)

fp2int_test(float('inf'), 'inf test', True)

fp2int_test(float('nan'), 'NaN test', True)

# test numbers < 1 (this used to fail; see issue #1044)

fp2int_test(0.0001, 'small num', False)

struct.pack('I', int(1/2))