test/float2int_fp30: Variant of float2int for 30-bit stuffed float.

tests/float/float2int_fp30.py

+# 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(14187744.))
+print("%d" % 14187744.)
+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
+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.**126., 'large neg', False)
+    fp2int_test(1.999999879*2.**126., '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))