diff options
Diffstat (limited to 'Modules/_randommodule.c')
| -rw-r--r-- | Modules/_randommodule.c | 113 |
1 files changed, 47 insertions, 66 deletions
diff --git a/Modules/_randommodule.c b/Modules/_randommodule.c index 21a2b09..416e266 100644 --- a/Modules/_randommodule.c +++ b/Modules/_randommodule.c @@ -168,9 +168,9 @@ init_genrand(RandomObject *self, unsigned long s) /* init_key is the array for initializing keys */ /* key_length is its length */ static PyObject * -init_by_array(RandomObject *self, unsigned long init_key[], unsigned long key_length) +init_by_array(RandomObject *self, unsigned long init_key[], size_t key_length) { - unsigned int i, j, k; /* was signed in the original code. RDH 12/16/2002 */ + size_t i, j, k; /* was signed in the original code. RDH 12/16/2002 */ unsigned long *mt; mt = self->state; @@ -179,7 +179,7 @@ init_by_array(RandomObject *self, unsigned long init_key[], unsigned long key_le k = (N>key_length ? N : key_length); for (; k; k--) { mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL)) - + init_key[j] + j; /* non linear */ + + init_key[j] + (unsigned long)j; /* non linear */ mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ i++; j++; if (i>=N) { mt[0] = mt[N-1]; i=1; } @@ -187,7 +187,7 @@ init_by_array(RandomObject *self, unsigned long init_key[], unsigned long key_le } for (k=N-1; k; k--) { mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL)) - - i; /* non linear */ + - (unsigned long)i; /* non linear */ mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */ i++; if (i>=N) { mt[0] = mt[N-1]; i=1; } @@ -207,14 +207,11 @@ static PyObject * random_seed(RandomObject *self, PyObject *args) { PyObject *result = NULL; /* guilty until proved innocent */ - PyObject *masklower = NULL; - PyObject *thirtytwo = NULL; PyObject *n = NULL; - unsigned long *new_key, *key = NULL; - unsigned long keymax; /* # of allocated slots in key */ - unsigned long keyused; /* # of used slots in key */ - int err; - + unsigned long *key = NULL; + unsigned char *key_as_bytes = NULL; + size_t bits, keyused, i; + int res; PyObject *arg = NULL; if (!PyArg_UnpackTuple(args, "seed", 0, 1, &arg)) @@ -243,69 +240,46 @@ random_seed(RandomObject *self, PyObject *args) if (n == NULL) goto Done; - /* Now split n into 32-bit chunks, from the right. Each piece is - * stored into key, which has a capacity of keymax chunks, of which - * keyused are filled. Alas, the repeated shifting makes this a - * quadratic-time algorithm; we'd really like to use - * _PyLong_AsByteArray here, but then we'd have to break into the - * long representation to figure out how big an array was needed - * in advance. - */ - keymax = 8; /* arbitrary; grows later if needed */ - keyused = 0; - key = (unsigned long *)PyMem_Malloc(keymax * sizeof(*key)); - if (key == NULL) + /* Now split n into 32-bit chunks, from the right. */ + bits = _PyLong_NumBits(n); + if (bits == (size_t)-1 && PyErr_Occurred()) goto Done; - masklower = PyLong_FromUnsignedLong(0xffffffffU); - if (masklower == NULL) + /* Figure out how many 32-bit chunks this gives us. */ + keyused = bits == 0 ? 1 : (bits - 1) / 32 + 1; + + /* Convert seed to byte sequence. */ + key_as_bytes = (unsigned char *)PyMem_Malloc((size_t)4 * keyused); + if (key_as_bytes == NULL) { + PyErr_NoMemory(); goto Done; - thirtytwo = PyLong_FromLong(32L); - if (thirtytwo == NULL) + } + res = _PyLong_AsByteArray((PyLongObject *)n, + key_as_bytes, keyused * 4, + 1, /* little-endian */ + 0); /* unsigned */ + if (res == -1) { + PyMem_Free(key_as_bytes); goto Done; - while ((err=PyObject_IsTrue(n))) { - PyObject *newn; - PyObject *pychunk; - unsigned long chunk; - - if (err == -1) - goto Done; - pychunk = PyNumber_And(n, masklower); - if (pychunk == NULL) - goto Done; - chunk = PyLong_AsUnsignedLong(pychunk); - Py_DECREF(pychunk); - if (chunk == (unsigned long)-1 && PyErr_Occurred()) - goto Done; - newn = PyNumber_Rshift(n, thirtytwo); - if (newn == NULL) - goto Done; - Py_DECREF(n); - n = newn; - if (keyused >= keymax) { - unsigned long bigger = keymax << 1; - if ((bigger >> 1) != keymax || - bigger > PY_SSIZE_T_MAX / sizeof(*key)) { - PyErr_NoMemory(); - goto Done; - } - new_key = (unsigned long *)PyMem_Realloc(key, - bigger * sizeof(*key)); - if (new_key == NULL) - goto Done; - key = new_key; - keymax = bigger; - } - assert(keyused < keymax); - key[keyused++] = chunk; } - if (keyused == 0) - key[keyused++] = 0UL; + /* Fill array of unsigned longs from byte sequence. */ + key = (unsigned long *)PyMem_Malloc(sizeof(unsigned long) * keyused); + if (key == NULL) { + PyErr_NoMemory(); + PyMem_Free(key_as_bytes); + goto Done; + } + for (i = 0; i < keyused; i++) { + key[i] = + ((unsigned long)key_as_bytes[4*i + 0] << 0) + + ((unsigned long)key_as_bytes[4*i + 1] << 8) + + ((unsigned long)key_as_bytes[4*i + 2] << 16) + + ((unsigned long)key_as_bytes[4*i + 3] << 24); + } + PyMem_Free(key_as_bytes); result = init_by_array(self, key, keyused); Done: - Py_XDECREF(masklower); - Py_XDECREF(thirtytwo); Py_XDECREF(n); PyMem_Free(key); return result; @@ -366,6 +340,10 @@ random_setstate(RandomObject *self, PyObject *state) index = PyLong_AsLong(PyTuple_GET_ITEM(state, i)); if (index == -1 && PyErr_Occurred()) return NULL; + if (index < 0 || index > N) { + PyErr_SetString(PyExc_ValueError, "invalid state"); + return NULL; + } self->index = (int)index; Py_INCREF(Py_None); @@ -389,6 +367,9 @@ random_getrandbits(RandomObject *self, PyObject *args) return NULL; } + if (k <= 32) /* Fast path */ + return PyLong_FromUnsignedLong(genrand_int32(self) >> (32 - k)); + bytes = ((k - 1) / 32 + 1) * 4; bytearray = (unsigned char *)PyMem_Malloc(bytes); if (bytearray == NULL) { |