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* bignum.c (MAX_BIG2STR_TABLE_ENTRIES): Use SIZEOF_SIZE_T.

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(power_cache_get_power0): Add rb_bug call for too bit i argument.
  (power_cache_get_power): Simplified.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42274 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
akr 2013-07-31 10:58:58 +00:00
parent 601f783827
commit aba8c29a8b
2 changed files with 23 additions and 11 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
Wed Jul 31 19:55:33 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (MAX_BIG2STR_TABLE_ENTRIES): Use SIZEOF_SIZE_T.
(power_cache_get_power0): Add rb_bug call for too bit i argument.
(power_cache_get_power): Simplified.
Wed Jul 31 18:32:25 2013 Akinori MUSHA <knu@iDaemons.org>
* lib/uri/common.rb (URI.decode_www_form_component): Use String#b.

28
bignum.c
View file

@ -4082,7 +4082,7 @@ big_rshift(VALUE x, unsigned long shift)
#define LOG2_KARATSUBA_BIG2STR_DIGITS 7
#define KARATSUBA_BIG2STR_DIGITS (1L<<LOG2_KARATSUBA_BIG2STR_DIGITS)
#define MAX_BIG2STR_TABLE_ENTRIES 64
#define MAX_BIG2STR_TABLE_ENTRIES (SIZEOF_SIZE_T * CHAR_BIT)
static VALUE big2str_power_cache[35][MAX_BIG2STR_TABLE_ENTRIES];
@ -4100,6 +4100,21 @@ power_cache_init(void)
static inline VALUE
power_cache_get_power0(int base, int i)
{
/* MAX_BIG2STR_TABLE_ENTRIES is big enough to that
* big2str_power_cache[base][MAX_BIG2STR_TABLE_ENTRIES-1] fills whole memory.
* So MAX_BIG2STR_TABLE_ENTRIES <= i is not possible to calculate.
*
* big2str_power_cache[base][MAX_BIG2STR_TABLE_ENTRIES-1] =
* (base**KARATSUBA_BIG2STR_DIGITS)**(MAX_BIG2STR_TABLE_ENTRIES-1) =
* (base**KARATSUBA_BIG2STR_DIGITS)**(SIZEOF_SIZE_T*CHAR_BIT-1) =
* base**(KARATSUBA_BIG2STR_DIGITS*(SIZEOF_SIZE_T*CHAR_BIT-1)) > 2**(SIZEOF_SIZE_T*CHAR_BIT-1)
* where
* 2 <= base
* 1 < KARATSUBA_BIG2STR_DIGITS
*/
if (MAX_BIG2STR_TABLE_ENTRIES <= i)
rb_bug("too big power number requested: (%d**%ld)**(2**%d)", base, KARATSUBA_BIG2STR_DIGITS, i);
if (NIL_P(big2str_power_cache[base - 2][i])) {
big2str_power_cache[base - 2][i] =
i == 0 ? rb_big_pow(rb_int2big(base), INT2FIX(KARATSUBA_BIG2STR_DIGITS))
@ -4113,24 +4128,15 @@ static VALUE
power_cache_get_power(int base, long n1, long* m1)
{
int i, m;
long j;
VALUE t;
if (n1 <= KARATSUBA_BIG2STR_DIGITS)
rb_bug("n1 > KARATSUBA_BIG2STR_DIGITS");
m = bitsize(n1-1); /* ceil(log2(n1)) */
if (m1) *m1 = 1 << m;
if (m1) *m1 = 1 << m; /* smallest x which n1 <= x and x is a power of 2. */
i = m - LOG2_KARATSUBA_BIG2STR_DIGITS;
if (i >= MAX_BIG2STR_TABLE_ENTRIES)
i = MAX_BIG2STR_TABLE_ENTRIES - 1;
t = power_cache_get_power0(base, i);
j = KARATSUBA_BIG2STR_DIGITS*(1 << i);
while (n1 > j) {
t = bigsq(t);
j *= 2;
}
return t;
}