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Reduce the size of the _PyLong_DigitValue table.

This commit is contained in:
Raymond Hettinger 2009-01-09 03:58:09 +00:00
parent 1467ac8e54
commit 3563153793
3 changed files with 8 additions and 4 deletions
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2
Include/longobject.h
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@ -41,7 +41,7 @@ PyAPI_FUNC(unsigned long) PyLong_AsUnsignedLongMask(PyObject *);
#endif #endif
/* For use by intobject.c only */ /* For use by intobject.c only */
PyAPI_DATA(int) _PyLong_DigitValue[256]; PyAPI_DATA(unsigned char) _PyLong_DigitValue[256];
/* _PyLong_AsScaledDouble returns a double x and an exponent e such that /* _PyLong_AsScaledDouble returns a double x and an exponent e such that
the true value is approximately equal to x * 2**(SHIFT*e). e is >= 0. the true value is approximately equal to x * 2**(SHIFT*e). e is >= 0.

4
Misc/NEWS
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@ -12,6 +12,10 @@ What's New in Python 3.1 alpha 0
Core and Builtins Core and Builtins
----------------- -----------------
- The internal table, _PyLong_DigitValue, is now an array of unsigned chars
instead of ints (reducing its size from 4 to 8 times thereby reducing
Python's overall memory).
- Issue #1180193: When importing a module from a .pyc (or .pyo) file with - Issue #1180193: When importing a module from a .pyc (or .pyo) file with
an existing .py counterpart, override the co_filename attributes of all an existing .py counterpart, override the co_filename attributes of all
code objects if the original filename is obsolete (which can happen if the code objects if the original filename is obsolete (which can happen if the

6
Objects/longobject.c
View File

@ -1646,7 +1646,7 @@ _PyLong_Format(PyObject *aa, int base)
* Note that when converting a base B string, a char c is a legitimate * Note that when converting a base B string, a char c is a legitimate
* base B digit iff _PyLong_DigitValue[Py_CHARPyLong_MASK(c)] < B. * base B digit iff _PyLong_DigitValue[Py_CHARPyLong_MASK(c)] < B.
*/ */
int _PyLong_DigitValue[256] = { unsigned char _PyLong_DigitValue[256] = {
37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37,
37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37,
37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37, 37,
@ -1710,7 +1710,7 @@ long_from_binary_base(char **str, int base)
bits_in_accum = 0; bits_in_accum = 0;
pdigit = z->ob_digit; pdigit = z->ob_digit;
while (--p >= start) { while (--p >= start) {
int k = _PyLong_DigitValue[Py_CHARMASK(*p)]; int k = (int)_PyLong_DigitValue[Py_CHARMASK(*p)];
assert(k >= 0 && k < base); assert(k >= 0 && k < base);
accum |= (twodigits)(k << bits_in_accum); accum |= (twodigits)(k << bits_in_accum);
bits_in_accum += bits_per_char; bits_in_accum += bits_per_char;
@ -1926,7 +1926,7 @@ digit beyond the first.
c = (digit)_PyLong_DigitValue[Py_CHARMASK(*str++)]; c = (digit)_PyLong_DigitValue[Py_CHARMASK(*str++)];
for (i = 1; i < convwidth && str != scan; ++i, ++str) { for (i = 1; i < convwidth && str != scan; ++i, ++str) {
c = (twodigits)(c * base + c = (twodigits)(c * base +
_PyLong_DigitValue[Py_CHARMASK(*str)]); (int)_PyLong_DigitValue[Py_CHARMASK(*str)]);
assert(c < PyLong_BASE); assert(c < PyLong_BASE);
} }