[Python-checkins] r69634 - in python/trunk: Include/longintrepr.h Lib/test/test_sys.py Misc/NEWS Objects/longobject.c
mark.dickinson
python-checkins at python.org
Sun Feb 15 11:13:42 CET 2009
Author: mark.dickinson
Date: Sun Feb 15 11:13:41 2009
New Revision: 69634
Log:
Issue #5260: Various portability and standards compliance fixes, optimizations
and cleanups in Objects/longobject.c. The most significant change is that
longs now use less memory: average savings are 2 bytes per long on 32-bit
systems and 6 bytes per long on 64-bit systems. (This memory saving already
exists in py3k.)
Modified:
python/trunk/Include/longintrepr.h
python/trunk/Lib/test/test_sys.py
python/trunk/Misc/NEWS
python/trunk/Objects/longobject.c
Modified: python/trunk/Include/longintrepr.h
==============================================================================
--- python/trunk/Include/longintrepr.h (original)
+++ python/trunk/Include/longintrepr.h Sun Feb 15 11:13:41 2009
@@ -19,14 +19,13 @@
long_pow() requires that SHIFT be divisible by 5. */
typedef unsigned short digit;
-typedef unsigned int wdigit; /* digit widened to parameter size */
#define BASE_TWODIGITS_TYPE long
typedef unsigned BASE_TWODIGITS_TYPE twodigits;
typedef BASE_TWODIGITS_TYPE stwodigits; /* signed variant of twodigits */
#define PyLong_SHIFT 15
#define PyLong_BASE ((digit)1 << PyLong_SHIFT)
-#define PyLong_MASK ((int)(PyLong_BASE - 1))
+#define PyLong_MASK ((digit)(PyLong_BASE - 1))
/* b/w compatibility with Python 2.5 */
#define SHIFT PyLong_SHIFT
Modified: python/trunk/Lib/test/test_sys.py
==============================================================================
--- python/trunk/Lib/test/test_sys.py (original)
+++ python/trunk/Lib/test/test_sys.py Sun Feb 15 11:13:41 2009
@@ -593,12 +593,12 @@
# listreverseiterator (list)
check(reversed([]), size(h + 'lP'))
# long
- check(0L, size(vh + 'H') - self.H)
- check(1L, size(vh + 'H'))
- check(-1L, size(vh + 'H'))
- check(32768L, size(vh + 'H') + self.H)
- check(32768L*32768L-1, size(vh + 'H') + self.H)
- check(32768L*32768L, size(vh + 'H') + 2*self.H)
+ check(0L, size(vh))
+ check(1L, size(vh) + self.H)
+ check(-1L, size(vh) + self.H)
+ check(32768L, size(vh) + 2*self.H)
+ check(32768L*32768L-1, size(vh) + 2*self.H)
+ check(32768L*32768L, size(vh) + 3*self.H)
# module
check(unittest, size(h + 'P'))
# None
Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS (original)
+++ python/trunk/Misc/NEWS Sun Feb 15 11:13:41 2009
@@ -12,6 +12,10 @@
Core and Builtins
-----------------
+- Issue #5260: Long integers now consume less memory: average
+ saving is 2 bytes per long on a 32-bit system and 6 bytes per long
+ on a 64-bit system.
+
- Issue #5186: Reduce hash collisions for objects with no __hash__ method by
rotating the object pointer by 4 bits to the right.
Modified: python/trunk/Objects/longobject.c
==============================================================================
--- python/trunk/Objects/longobject.c (original)
+++ python/trunk/Objects/longobject.c Sun Feb 15 11:13:41 2009
@@ -8,6 +8,7 @@
#include "longintrepr.h"
#include <ctype.h>
+#include <stddef.h>
/* For long multiplication, use the O(N**2) school algorithm unless
* both operands contain more than KARATSUBA_CUTOFF digits (this
@@ -30,12 +31,6 @@
#define MAX(x, y) ((x) < (y) ? (y) : (x))
#define MIN(x, y) ((x) > (y) ? (y) : (x))
-/* Forward */
-static PyLongObject *long_normalize(PyLongObject *);
-static PyLongObject *mul1(PyLongObject *, wdigit);
-static PyLongObject *muladd1(PyLongObject *, wdigit, wdigit);
-static PyLongObject *divrem1(PyLongObject *, digit, digit *);
-
#define SIGCHECK(PyTryBlock) \
if (--_Py_Ticker < 0) { \
_Py_Ticker = _Py_CheckInterval; \
@@ -62,16 +57,20 @@
/* Allocate a new long int object with size digits.
Return NULL and set exception if we run out of memory. */
+#define MAX_LONG_DIGITS \
+ ((PY_SSIZE_T_MAX - offsetof(PyLongObject, ob_digit))/sizeof(digit))
+
PyLongObject *
_PyLong_New(Py_ssize_t size)
{
- if (size > PY_SSIZE_T_MAX) {
- PyErr_NoMemory();
+ if (size > MAX_LONG_DIGITS) {
+ PyErr_SetString(PyExc_OverflowError,
+ "too many digits in integer");
return NULL;
}
/* coverity[ampersand_in_size] */
- /* XXX(nnorwitz): This can overflow --
- PyObject_NEW_VAR / _PyObject_VAR_SIZE need to detect overflow */
+ /* XXX(nnorwitz): PyObject_NEW_VAR / _PyObject_VAR_SIZE need to detect
+ overflow */
return PyObject_NEW_VAR(PyLongObject, &PyLong_Type, size);
}
@@ -197,8 +196,8 @@
return NULL;
frac = ldexp(frac, (expo-1) % PyLong_SHIFT + 1);
for (i = ndig; --i >= 0; ) {
- long bits = (long)frac;
- v->ob_digit[i] = (digit) bits;
+ digit bits = (digit)frac;
+ v->ob_digit[i] = bits;
frac = frac - (double)bits;
frac = ldexp(frac, PyLong_SHIFT);
}
@@ -438,9 +437,9 @@
int incr; /* direction to move pstartbyte */
const unsigned char* pendbyte; /* MSB of bytes */
size_t numsignificantbytes; /* number of bytes that matter */
- size_t ndigits; /* number of Python long digits */
+ Py_ssize_t ndigits; /* number of Python long digits */
PyLongObject* v; /* result */
- int idigit = 0; /* next free index in v->ob_digit */
+ Py_ssize_t idigit = 0; /* next free index in v->ob_digit */
if (n == 0)
return PyLong_FromLong(0L);
@@ -483,12 +482,16 @@
}
/* How many Python long digits do we need? We have
- 8*numsignificantbytes bits, and each Python long digit has PyLong_SHIFT
- bits, so it's the ceiling of the quotient. */
+ 8*numsignificantbytes bits, and each Python long digit has
+ PyLong_SHIFT bits, so it's the ceiling of the quotient. */
+ /* catch overflow before it happens */
+ if (numsignificantbytes > (PY_SSIZE_T_MAX - PyLong_SHIFT) / 8) {
+ PyErr_SetString(PyExc_OverflowError,
+ "byte array too long to convert to int");
+ return NULL;
+ }
ndigits = (numsignificantbytes * 8 + PyLong_SHIFT - 1) / PyLong_SHIFT;
- if (ndigits > (size_t)INT_MAX)
- return PyErr_NoMemory();
- v = _PyLong_New((int)ndigits);
+ v = _PyLong_New(ndigits);
if (v == NULL)
return NULL;
@@ -517,8 +520,9 @@
accumbits += 8;
if (accumbits >= PyLong_SHIFT) {
/* There's enough to fill a Python digit. */
- assert(idigit < (int)ndigits);
- v->ob_digit[idigit] = (digit)(accum & PyLong_MASK);
+ assert(idigit < ndigits);
+ v->ob_digit[idigit] = (digit)(accum &
+ PyLong_MASK);
++idigit;
accum >>= PyLong_SHIFT;
accumbits -= PyLong_SHIFT;
@@ -527,7 +531,7 @@
}
assert(accumbits < PyLong_SHIFT);
if (accumbits) {
- assert(idigit < (int)ndigits);
+ assert(idigit < ndigits);
v->ob_digit[idigit] = (digit)accum;
++idigit;
}
@@ -1124,19 +1128,11 @@
/* Multiply by a single digit, ignoring the sign. */
static PyLongObject *
-mul1(PyLongObject *a, wdigit n)
-{
- return muladd1(a, n, (digit)0);
-}
-
-/* Multiply by a single digit and add a single digit, ignoring the sign. */
-
-static PyLongObject *
-muladd1(PyLongObject *a, wdigit n, wdigit extra)
+mul1(PyLongObject *a, digit n)
{
Py_ssize_t size_a = ABS(Py_SIZE(a));
PyLongObject *z = _PyLong_New(size_a+1);
- twodigits carry = extra;
+ twodigits carry = 0;
Py_ssize_t i;
if (z == NULL)
@@ -1757,8 +1753,6 @@
static PyLongObject *x_divrem
(PyLongObject *, PyLongObject *, PyLongObject **);
static PyObject *long_long(PyObject *v);
-static int long_divrem(PyLongObject *, PyLongObject *,
- PyLongObject **, PyLongObject **);
/* Long division with remainder, top-level routine */
@@ -1976,14 +1970,12 @@
sign = -1;
i = -(i);
}
-#define LONG_BIT_PyLong_SHIFT (8*sizeof(long) - PyLong_SHIFT)
/* The following loop produces a C unsigned long x such that x is
congruent to the absolute value of v modulo ULONG_MAX. The
resulting x is nonzero if and only if v is. */
while (--i >= 0) {
/* Force a native long #-bits (32 or 64) circular shift */
- x = ((x << PyLong_SHIFT) & ~PyLong_MASK) |
- ((x >> LONG_BIT_PyLong_SHIFT) & PyLong_MASK);
+ x = (x >> (8*SIZEOF_LONG-PyLong_SHIFT)) | (x << PyLong_SHIFT);
x += v->ob_digit[i];
/* If the addition above overflowed we compensate by
incrementing. This preserves the value modulo
@@ -1991,11 +1983,10 @@
if (x < v->ob_digit[i])
x++;
}
-#undef LONG_BIT_PyLong_SHIFT
x = x * sign;
- if (x == -1)
- x = -2;
- return x;
+ if (x == (unsigned long)-1)
+ x = (unsigned long)-2;
+ return (long)x;
}
@@ -3337,7 +3328,7 @@
/* Since PyLong_FromString doesn't have a length parameter,
* check here for possible NULs in the string. */
char *string = PyString_AS_STRING(x);
- if (strlen(string) != PyString_Size(x)) {
+ if (strlen(string) != (size_t)PyString_Size(x)) {
/* create a repr() of the input string,
* just like PyLong_FromString does. */
PyObject *srepr;
@@ -3443,9 +3434,7 @@
{
Py_ssize_t res;
- res = v->ob_type->tp_basicsize;
- if (v->ob_size != 0)
- res += abs(v->ob_size) * sizeof(digit);
+ res = v->ob_type->tp_basicsize + ABS(Py_SIZE(v))*sizeof(digit);
return PyInt_FromSsize_t(res);
}
@@ -3619,7 +3608,7 @@
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
"long", /* tp_name */
- sizeof(PyLongObject) - sizeof(digit), /* tp_basicsize */
+ offsetof(PyLongObject, ob_digit), /* tp_basicsize */
sizeof(digit), /* tp_itemsize */
long_dealloc, /* tp_dealloc */
0, /* tp_print */
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