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| author | Charles Harris <charlesr.harris@gmail.com> | 2016-07-10 11:37:31 -0600 |
|---|---|---|
| committer | Charles Harris <charlesr.harris@gmail.com> | 2016-07-10 14:06:35 -0600 |
| commit | 2d24f8a41da440b53ffe953de14c2e1117df07f0 (patch) | |
| tree | f0cd5abc634ad0d708bd10274586220b3f79b13b | |
| parent | d3e3d91d401f5e47a81e748cd7fb12620b45947a (diff) | |
| download | numpy-2d24f8a41da440b53ffe953de14c2e1117df07f0.tar.gz | |
BUG: Make sure npy_mul_with_overflow_<type> detects overflow.
The previous check for overflow would fail with signed integers as it
was designed to check for overflow of the larger corresponding unsigned
type.
| -rw-r--r-- | numpy/core/src/private/templ_common.h.src | 9 | ||||
| -rw-r--r-- | numpy/core/tests/test_multiarray.py | 15 |
2 files changed, 21 insertions, 3 deletions
diff --git a/numpy/core/src/private/templ_common.h.src b/numpy/core/src/private/templ_common.h.src index dd6c7bf23..a65a00758 100644 --- a/numpy/core/src/private/templ_common.h.src +++ b/numpy/core/src/private/templ_common.h.src @@ -17,6 +17,10 @@ /* * writes result of a * b into r * returns 1 if a * b overflowed else returns 0 + * + * These functions are not designed to work if either a or b is negative, but + * that is not checked. Could use absolute values and adjust the sign if that + * functionality was desired. */ static NPY_INLINE int npy_mul_with_overflow_@name@(@type@ * r, @type@ a, @type@ b) @@ -24,17 +28,16 @@ npy_mul_with_overflow_@name@(@type@ * r, @type@ a, @type@ b) #ifdef HAVE___BUILTIN_MUL_OVERFLOW return __builtin_mul_overflow(a, b, r); #else - const @type@ half_sz = (((@type@)1 << (sizeof(a) * 8 / 2)) - 1); + const @type@ half_sz = ((@type@)1 << ((sizeof(a) * 8 - 1 ) / 2)); *r = a * b; /* * avoid expensive division on common no overflow case */ if (NPY_UNLIKELY((a | b) >= half_sz) && - a != 0 && b > @MAX@ / a) { + a != 0 && b > @MAX@ / a) { return 1; } - return 0; #endif } diff --git a/numpy/core/tests/test_multiarray.py b/numpy/core/tests/test_multiarray.py index ca13a172f..542dfa843 100644 --- a/numpy/core/tests/test_multiarray.py +++ b/numpy/core/tests/test_multiarray.py @@ -564,6 +564,21 @@ class TestCreation(TestCase): arr = np.array([], dtype='V') assert_equal(arr.dtype.kind, 'V') + def test_too_big_error(self): + # 45341 is the smallest integer greater than sqrt(2**31 - 1). + # 3037000500 is the smallest integer greater than sqrt(2**63 - 1). + # We want to make sure that the square byte array with those dimensions + # is too big on 32 or 64 bit systems respectively. + if np.iinfo('intp').max == 2**31 - 1: + shape = (46341, 46341) + elif np.iinfo('intp').max == 2**63 - 1: + shape = (3037000500, 3037000500) + else: + return + assert_raises(ValueError, np.empty, shape, dtype=np.int8) + assert_raises(ValueError, np.zeros, shape, dtype=np.int8) + assert_raises(ValueError, np.ones, shape, dtype=np.int8) + def test_zeros(self): types = np.typecodes['AllInteger'] + np.typecodes['AllFloat'] for dt in types: |