Python math.h() Examples

def test_FILE_stored_explicitly():
    ffi = FFI()
    ffi.cdef("int myprintf11(const char *, int); FILE *myfile;")
    lib = ffi.verify("""
        #include <stdio.h>
        FILE *myfile;
        int myprintf11(const char *out, int value) {
            return fprintf(myfile, out, value);
        }
    """)
    import os
    fdr, fdw = os.pipe()
    fw1 = os.fdopen(fdw, 'wb', 256)
    lib.myfile = ffi.cast("FILE *", fw1)
    #
    fw1.write(b"X")
    r = lib.myprintf11(b"hello, %d!\n", ffi.cast("int", 42))
    fw1.close()
    assert r == len("hello, 42!\n")
    #
    result = os.read(fdr, 256)
    os.close(fdr)
    # the 'X' might remain in the user-level buffer of 'fw1' and
    # end up showing up after the 'hello, 42!\n'
    assert result == b"Xhello, 42!\n" or result == b"hello, 42!\nX" 

def test_opaque_integer_as_function_result():
    #import platform
    #if platform.machine().startswith('sparc'):
    #    py.test.skip('Breaks horribly on sparc (SIGILL + corrupted stack)')
    #elif platform.machine() == 'mips64' and sys.maxsize > 2**32:
    #    py.test.skip('Segfaults on mips64el')
    # XXX bad abuse of "struct { ...; }".  It only works a bit by chance
    # anyway.  XXX think about something better :-(
    ffi = FFI()
    ffi.cdef("""
        typedef struct { ...; } myhandle_t;
        myhandle_t foo(void);
    """)
    lib = ffi.verify("""
        typedef short myhandle_t;
        myhandle_t foo(void) { return 42; }
    """)
    h = lib.foo()
    assert ffi.sizeof(h) == ffi.sizeof("short") 

def test_opaque_integer_as_function_result():
    #import platform
    #if platform.machine().startswith('sparc'):
    #    py.test.skip('Breaks horribly on sparc (SIGILL + corrupted stack)')
    #elif platform.machine() == 'mips64' and sys.maxsize > 2**32:
    #    py.test.skip('Segfaults on mips64el')
    # XXX bad abuse of "struct { ...; }".  It only works a bit by chance
    # anyway.  XXX think about something better :-(
    ffi = FFI()
    ffi.cdef("""
        typedef struct { ...; } myhandle_t;
        myhandle_t foo(void);
    """)
    lib = ffi.verify("""
        typedef short myhandle_t;
        myhandle_t foo(void) { return 42; }
    """)
    h = lib.foo()
    assert ffi.sizeof(h) == ffi.sizeof("short") 

def test_FILE_stored_explicitly():
    ffi = FFI()
    ffi.cdef("int myprintf11(const char *, int); FILE *myfile;")
    lib = ffi.verify("""
        #include <stdio.h>
        FILE *myfile;
        int myprintf11(const char *out, int value) {
            return fprintf(myfile, out, value);
        }
    """)
    import os
    fdr, fdw = os.pipe()
    fw1 = os.fdopen(fdw, 'wb', 256)
    lib.myfile = ffi.cast("FILE *", fw1)
    #
    fw1.write(b"X")
    r = lib.myprintf11(b"hello, %d!\n", ffi.cast("int", 42))
    fw1.close()
    assert r == len("hello, 42!\n")
    #
    result = os.read(fdr, 256)
    os.close(fdr)
    # the 'X' might remain in the user-level buffer of 'fw1' and
    # end up showing up after the 'hello, 42!\n'
    assert result == b"Xhello, 42!\n" or result == b"hello, 42!\nX" 

def test_errno_working_even_with_pypys_jit():
    ffi = FFI()
    ffi.cdef("int f(int);")
    lib = ffi.verify("""
        #include <errno.h>
        int f(int x) { return (errno = errno + x); }
    """)
    @_run_in_multiple_threads
    def test1():
        ffi.errno = 0
        for i in range(10000):
            e = lib.f(1)
            assert e == i + 1
            assert ffi.errno == e
        for i in range(10000):
            ffi.errno = i
            e = lib.f(42)
            assert e == i + 42 

def test_take_and_return_partial_structs():
    ffi = FFI()
    ffi.cdef("""
        typedef struct { int x; ...; } foo_t;
        foo_t foo(foo_t, foo_t);
    """)
    lib = ffi.verify("""
        typedef struct { int y, x; } foo_t;
        foo_t foo(foo_t a, foo_t b) {
            foo_t r = { 100, a.x * 5 + b.x * 7 };
            return r;
        }
    """)
    args = ffi.new("foo_t[3]")
    args[0].x = 1000
    args[2].x = -498
    h = lib.foo(args[0], args[2])
    assert ffi.sizeof(h) == 2 * ffi.sizeof("int")
    assert h.x == 1000 * 5 - 498 * 7 

def test_extension_object(self):
        ffi = FFI()
        ffi.cdef("double sin(double x);")
        csrc = '/*7%s*/' % self + '''
    #include <math.h>
    #ifndef TEST_EXTENSION_OBJECT
    # error "define_macros missing"
    #endif
    '''
        lib = ffi.verify(csrc, define_macros=[('TEST_EXTENSION_OBJECT', '1')],
                         force_generic_engine=self.generic,
                         libraries=[self.lib_m])
        assert lib.sin(12.3) == math.sin(12.3)
        v = ffi.verifier
        ext = v.get_extension()
        assert 'distutils.extension.Extension' in str(ext.__class__) or \
               'setuptools.extension.Extension' in str(ext.__class__)
        assert ext.sources == [maybe_relative_path(v.sourcefilename)]
        assert ext.name == v.get_module_name()
        assert ext.define_macros == [('TEST_EXTENSION_OBJECT', '1')] 

def test_unicode_libraries():
    try:
        unicode
    except NameError:
        py.test.skip("for python 2.x")
    #
    import math
    lib_m = "m"
    if sys.platform == 'win32':
        #there is a small chance this fails on Mingw via environ $CC
        import distutils.ccompiler
        if distutils.ccompiler.get_default_compiler() == 'msvc':
            lib_m = 'msvcrt'
    ffi = FFI()
    ffi.cdef(unicode("float sin(double); double cos(double);"))
    lib = verify(ffi, 'test_math_sin_unicode', unicode('#include <math.h>'),
                 libraries=[unicode(lib_m)])
    assert lib.cos(1.43) == math.cos(1.43) 

def test_ptr_to_opaque():
    ffi = FFI()
    ffi.cdef("typedef ... foo_t; int f1(foo_t*); foo_t *f2(int);")
    lib = ffi.verify("""
        #include <stdlib.h>
        typedef struct { int x; } foo_t;
        int f1(foo_t* p) {
            int x = p->x;
            free(p);
            return x;
        }
        foo_t *f2(int x) {
            foo_t *p = malloc(sizeof(foo_t));
            p->x = x;
            return p;
        }
    """)
    p = lib.f2(42)
    x = lib.f1(p)
    assert x == 42 

def test_implicit_unicode_on_windows():
    if sys.platform != 'win32':
        py.test.skip("win32-only test")
    ffi = FFI()
    e = py.test.raises(FFIError, ffi.cdef, "int foo(LPTSTR);")
    assert str(e.value) == ("The Windows type 'LPTSTR' is only available after"
                            " you call ffi.set_unicode()")
    for with_unicode in [True, False]:
        ffi = FFI()
        ffi.set_unicode(with_unicode)
        ffi.cdef("""
            DWORD GetModuleFileName(HMODULE hModule, LPTSTR lpFilename,
                                    DWORD nSize);
        """)
        lib = ffi.verify("""
            #include <windows.h>
        """, libraries=['Kernel32'])
        outbuf = ffi.new("TCHAR[]", 200)
        n = lib.GetModuleFileName(ffi.NULL, outbuf, 500)
        assert 0 < n < 500
        for i in range(n):
            #print repr(outbuf[i])
            assert ord(outbuf[i]) != 0
        assert ord(outbuf[n]) == 0
        assert ord(outbuf[0]) < 128     # should be a letter, or '\' 

def setUp(self):
        """NOTE this is called once for each test* method
        (it is not called once per class).
        FIXME This is slightly inefficient as it is called *way* more times than it needs to be.
        """
        header_str = """
#include <math.h>
#define sin_plus_y(x,y) (sin(x) + (y))
"""
        if sys.platform == "win32":
            # pick something from %windir%\system32\msvc*dll that include stdlib
            libraries = ["msvcrt.dll"]
            libraries = ["msvcrt"]
        elif sys.platform.startswith("linux"):
            libraries = ["libm.so.6"]
        else:
            libraries = ["libc"]
        self.module, output = ctypesgentest.test(header_str, libraries=libraries, all_headers=True) 

def test_abs_fallback_expr():
    expr = ast.AbsExpr(ast.NumVal(-2.0))

    interpreter = CInterpreter()
    interpreter.abs_function_name = NotImplemented

    expected_code = """
#include <math.h>
double score(double * input) {
    double var0;
    double var1;
    var1 = -2.0;
    if ((var1) < (0)) {
        var0 = (0.0) - (var1);
    } else {
        var0 = var1;
    }
    return var0;
}
"""

    assert_code_equal(interpreter.interpret(expr), expected_code) 

def cleanup_json_src_paths(json):
    """
    JSON stores the path to some source items.  These need to be genericized in
    order for tests to succeed on all machines/user accounts.
    """
    TYPES_W_PATHS = ["CtypesStruct", "CtypesEnum"]
    for i in json:
        if "ctype" in i and i["ctype"]["Klass"] in TYPES_W_PATHS:
            i["ctype"]["src"][0] = "/some-path/temp.h" 

def rotation_matrix_weave(axis, theta, mat=None):
    try:
        from scipy import weave
    except ImportError:
        raise NotImplementedError
    if mat is None:
        mat = np.eye(3, 3)

    support = "#include <math.h>"
    code = """
        double x = sqrt(axis[0] * axis[0] + axis[1] * axis[1] + axis[2] * axis[2]);
        double a = cos(theta / 2.0);
        double b = -(axis[0] / x) * sin(theta / 2.0);
        double c = -(axis[1] / x) * sin(theta / 2.0);
        double d = -(axis[2] / x) * sin(theta / 2.0);

        mat[0] = a*a + b*b - c*c - d*d;
        mat[1] = 2 * (b*c - a*d);
        mat[2] = 2 * (b*d + a*c);

        mat[3*1 + 0] = 2*(b*c+a*d);
        mat[3*1 + 1] = a*a+c*c-b*b-d*d;
        mat[3*1 + 2] = 2*(c*d-a*b);

        mat[3*2 + 0] = 2*(b*d-a*c);
        mat[3*2 + 1] = 2*(c*d+a*b);
        mat[3*2 + 2] = a*a+d*d-b*b-c*c;
    """

    weave.inline(code, ['axis', 'theta', 'mat'], support_code=support, libraries=['m'])

    return mat 

def test_strlen_array_of_char():
    ffi = FFI()
    ffi.cdef("size_t strlen(char[]);")
    lib = ffi.verify("#include <string.h>")
    assert lib.strlen(b"hello") == 5 

def setUp(self):
        """NOTE this is called once for each test* method
        (it is not called once per class).
        FIXME This is slightly inefficient as it is called *way* more times than it needs to be.
        """
        header_str = "#include <stdlib.h>\n"
        if sys.platform == "win32":
            # pick something from %windir%\system32\msvc*dll that include stdlib
            libraries = ["msvcrt.dll"]
            libraries = ["msvcrt"]
        elif sys.platform.startswith("linux"):
            libraries = ["libc.so.6"]
        else:
            libraries = ["libc"]
        self.module, output = ctypesgentest.test(header_str, libraries=libraries, all_headers=True) 

def c_headers(self, c_compiler):
        l = ['<math.h>']
        # These includes are needed by Scalar and TensorType,
        # we declare them here and they will be re-used by TensorType
        l.append('<numpy/arrayobject.h>')
        l.append('<numpy/arrayscalars.h>')
        if config.lib.amdlibm and c_compiler.supports_amdlibm:
            l += ['<amdlibm.h>']
        return l 

def setUp(self):
        """NOTE this is called once for each test* method
        (it is not called once per class).
        FIXME This is slightly inefficient as it is called *way* more times than it needs to be.
        """
        header_str = """
#include <stdbool.h>

struct foo
{
    bool is_bar;
    int a;
};
"""
        self.module, _ = ctypesgentest.test(header_str)  # , all_headers=True) 

def c_headers(self, c_compiler):
        l = ['<math.h>']
        # These includes are needed by Scalar and TensorType,
        # we declare them here and they will be re-used by TensorType
        l.append('<numpy/arrayobject.h>')
        l.append('<numpy/arrayscalars.h>')
        if config.lib.amdlibm and c_compiler.supports_amdlibm:
            l += ['<amdlibm.h>']
        return l 

def test_math_sin_type():
    ffi = FFI()
    ffi.cdef("double sin(double);")
    lib = verify(ffi, 'test_math_sin_type', '#include <math.h>')
    # 'lib.sin' is typed as a <built-in method> object on lib
    assert ffi.typeof(lib.sin).cname == "double(*)(double)"
    # 'x' is another <built-in method> object on lib, made very indirectly
    x = type(lib).__dir__.__get__(lib)
    py.test.raises(TypeError, ffi.typeof, x)
    #
    # present on built-in functions on CPython; must be emulated on PyPy:
    assert lib.sin.__name__ == 'sin'
    assert lib.sin.__module__ == '_CFFI_test_math_sin_type'
    assert lib.sin.__doc__ == 'direct call to the C function of the same name' 

def test_help(self):
        """Test that script at least generates a help"""
        o, e, c = self._exec(["--help"])
        self.assertEqual(c, 0)
        self.assertEqual(
            o.decode().splitlines()[0], "Usage: run.py [options] /path/to/header.h ..."
        )
        self.assertGreater(len(o), 3000)  # its long, so it must be the generated help
        self.assertEqual(e.decode(), "") 

def test_array_as_argument():
    ffi = FFI()
    ffi.cdef("""
        size_t strlen(char string[]);
    """)
    ffi.verify("#include <string.h>") 

def test_func_as_argument():
    ffi = FFI()
    ffi.cdef("""
        void qsort(void *base, size_t nel, size_t width,
            int compar(const void *, const void *));
    """)
    ffi.verify("#include <stdlib.h>") 

def test_longdouble():
    ffi = FFI()
    ffi.cdef("long double sinl(long double x);")
    lib = ffi.verify('#include <math.h>', libraries=lib_m)
    for input in [1.23,
                  ffi.cast("double", 1.23),
                  ffi.cast("long double", 1.23)]:
        x = lib.sinl(input)
        assert repr(x).startswith("<cdata 'long double'")
        assert (float(x) - math.sin(1.23)) < 1E-10 

def test_relative_to():
    py.test.skip("not available")
    import tempfile, os
    from testing.udir import udir
    tmpdir = tempfile.mkdtemp(dir=str(udir))
    ffi = FFI()
    ffi.cdef("int foo(int);")
    f = open(os.path.join(tmpdir, 'foo.h'), 'w')
    f.write("int foo(int a) { return a + 42; }\n")
    f.close()
    lib = ffi.verify('#include "foo.h"',
                     include_dirs=['.'],
                     relative_to=os.path.join(tmpdir, 'x'))
    assert lib.foo(100) == 142 

def test_strlen_approximate():
    lib = _Wconversion("int strlen(char *s);",
                       "#include <string.h>")
    assert lib.strlen(b"hi there!") == 9 

def test_strlen_exact():
    ffi = FFI()
    ffi.cdef("size_t strlen(const char *s);")
    lib = ffi.verify("#include <string.h>")
    assert lib.strlen(b"hi there!") == 9 

def test_rounding_2():
    ffi = FFI()
    ffi.cdef("double sin(float x);")
    lib = ffi.verify('#include <math.h>', libraries=lib_m)
    res = lib.sin(1.23)
    assert res != math.sin(1.23)     # not exact, because of double->float
    assert abs(res - math.sin(1.23)) < 1E-5 

def test_Wconversion_double2int():
    _Wconversion("int sin(double);",
                 "#include <math.h>", libraries=lib_m) 

def test_Wconversion_float2int():
    _Wconversion("int sinf(float);",
                 "#include <math.h>", libraries=lib_m)