Current Path : /usr/local/lib/python2.5/ctypes/test/ |
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Current File : //usr/local/lib/python2.5/ctypes/test/test_numbers.py |
from ctypes import * import unittest import sys, struct def valid_ranges(*types): # given a sequence of numeric types, collect their _type_ # attribute, which is a single format character compatible with # the struct module, use the struct module to calculate the # minimum and maximum value allowed for this format. # Returns a list of (min, max) values. result = [] for t in types: fmt = t._type_ size = struct.calcsize(fmt) a = struct.unpack(fmt, ("\x00"*32)[:size])[0] b = struct.unpack(fmt, ("\xFF"*32)[:size])[0] c = struct.unpack(fmt, ("\x7F"+"\x00"*32)[:size])[0] d = struct.unpack(fmt, ("\x80"+"\xFF"*32)[:size])[0] result.append((min(a, b, c, d), max(a, b, c, d))) return result ArgType = type(byref(c_int(0))) unsigned_types = [c_ubyte, c_ushort, c_uint, c_ulong] signed_types = [c_byte, c_short, c_int, c_long, c_longlong] float_types = [c_double, c_float] try: c_ulonglong c_longlong except NameError: pass else: unsigned_types.append(c_ulonglong) signed_types.append(c_longlong) unsigned_ranges = valid_ranges(*unsigned_types) signed_ranges = valid_ranges(*signed_types) ################################################################ class NumberTestCase(unittest.TestCase): def test_default_init(self): # default values are set to zero for t in signed_types + unsigned_types + float_types: self.failUnlessEqual(t().value, 0) def test_unsigned_values(self): # the value given to the constructor is available # as the 'value' attribute for t, (l, h) in zip(unsigned_types, unsigned_ranges): self.failUnlessEqual(t(l).value, l) self.failUnlessEqual(t(h).value, h) def test_signed_values(self): # see above for t, (l, h) in zip(signed_types, signed_ranges): self.failUnlessEqual(t(l).value, l) self.failUnlessEqual(t(h).value, h) def test_typeerror(self): # Only numbers are allowed in the contructor, # otherwise TypeError is raised for t in signed_types + unsigned_types + float_types: self.assertRaises(TypeError, t, "") self.assertRaises(TypeError, t, None) ## def test_valid_ranges(self): ## # invalid values of the correct type ## # raise ValueError (not OverflowError) ## for t, (l, h) in zip(unsigned_types, unsigned_ranges): ## self.assertRaises(ValueError, t, l-1) ## self.assertRaises(ValueError, t, h+1) def test_from_param(self): # the from_param class method attribute always # returns PyCArgObject instances for t in signed_types + unsigned_types + float_types: self.failUnlessEqual(ArgType, type(t.from_param(0))) def test_byref(self): # calling byref returns also a PyCArgObject instance for t in signed_types + unsigned_types + float_types: parm = byref(t()) self.failUnlessEqual(ArgType, type(parm)) def test_floats(self): # c_float and c_double can be created from # Python int, long and float class FloatLike(object): def __float__(self): return 2.0 f = FloatLike() for t in float_types: self.failUnlessEqual(t(2.0).value, 2.0) self.failUnlessEqual(t(2).value, 2.0) self.failUnlessEqual(t(2L).value, 2.0) self.failUnlessEqual(t(f).value, 2.0) def test_integers(self): class FloatLike(object): def __float__(self): return 2.0 f = FloatLike() class IntLike(object): def __int__(self): return 2 i = IntLike() # integers cannot be constructed from floats, # but from integer-like objects for t in signed_types + unsigned_types: self.assertRaises(TypeError, t, 3.14) self.assertRaises(TypeError, t, f) self.failUnlessEqual(t(i).value, 2) def test_sizes(self): for t in signed_types + unsigned_types + float_types: size = struct.calcsize(t._type_) # sizeof of the type... self.failUnlessEqual(sizeof(t), size) # and sizeof of an instance self.failUnlessEqual(sizeof(t()), size) def test_alignments(self): for t in signed_types + unsigned_types + float_types: code = t._type_ # the typecode align = struct.calcsize("c%c" % code) - struct.calcsize(code) # alignment of the type... self.failUnlessEqual((code, alignment(t)), (code, align)) # and alignment of an instance self.failUnlessEqual((code, alignment(t())), (code, align)) def test_int_from_address(self): from array import array for t in signed_types + unsigned_types: # the array module doesn't suppport all format codes # (no 'q' or 'Q') try: array(t._type_) except ValueError: continue a = array(t._type_, [100]) # v now is an integer at an 'external' memory location v = t.from_address(a.buffer_info()[0]) self.failUnlessEqual(v.value, a[0]) self.failUnlessEqual(type(v), t) # changing the value at the memory location changes v's value also a[0] = 42 self.failUnlessEqual(v.value, a[0]) def test_float_from_address(self): from array import array for t in float_types: a = array(t._type_, [3.14]) v = t.from_address(a.buffer_info()[0]) self.failUnlessEqual(v.value, a[0]) self.failUnless(type(v) is t) a[0] = 2.3456e17 self.failUnlessEqual(v.value, a[0]) self.failUnless(type(v) is t) def test_char_from_address(self): from ctypes import c_char from array import array a = array('c', 'x') v = c_char.from_address(a.buffer_info()[0]) self.failUnlessEqual(v.value, a[0]) self.failUnless(type(v) is c_char) a[0] = '?' self.failUnlessEqual(v.value, a[0]) def test_init(self): # c_int() can be initialized from Python's int, and c_int. # Not from c_long or so, which seems strange, abd should # probably be changed: self.assertRaises(TypeError, c_int, c_long(42)) ## def test_perf(self): ## check_perf() from ctypes import _SimpleCData class c_int_S(_SimpleCData): _type_ = "i" __slots__ = [] def run_test(rep, msg, func, arg=None): ## items = [None] * rep items = range(rep) from time import clock if arg is not None: start = clock() for i in items: func(arg); func(arg); func(arg); func(arg); func(arg) stop = clock() else: start = clock() for i in items: func(); func(); func(); func(); func() stop = clock() print "%15s: %.2f us" % (msg, ((stop-start)*1e6/5/rep)) def check_perf(): # Construct 5 objects from ctypes import c_int REP = 200000 run_test(REP, "int()", int) run_test(REP, "int(999)", int) run_test(REP, "c_int()", c_int) run_test(REP, "c_int(999)", c_int) run_test(REP, "c_int_S()", c_int_S) run_test(REP, "c_int_S(999)", c_int_S) # Python 2.3 -OO, win2k, P4 700 MHz: # # int(): 0.87 us # int(999): 0.87 us # c_int(): 3.35 us # c_int(999): 3.34 us # c_int_S(): 3.23 us # c_int_S(999): 3.24 us # Python 2.2 -OO, win2k, P4 700 MHz: # # int(): 0.89 us # int(999): 0.89 us # c_int(): 9.99 us # c_int(999): 10.02 us # c_int_S(): 9.87 us # c_int_S(999): 9.85 us if __name__ == '__main__': ## check_perf() unittest.main()