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Code Releases Activity

* string.c (rb_str_clear): avoid revealing NULL pointer.

Browse source 
[ruby-dev:24766]

* string.c (str_gsub): add paranoid check. [ruby-dev:24827]

* string.c (str_mod_check): check frozen status as well.
  [ruby-dev:24801]

* lib/mathn.rb (Integer::gcd2): faster implementation by
  <erlercw@siu.edu>. [ruby-talk:120232]

* ext/gdbm/gdbm.c (fgdbm_store): StringValue() may alter string
  pointer.  [ruby-dev:24783]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@7265 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
matz 2004-11-14 15:41:40 +00:00
parent 8f1c92af4f
commit 0f36ecebe0
8 changed files with 82 additions and 47 deletions
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87
lib/mathn.rb
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@ -17,24 +17,13 @@ require "matrix.rb"
class Integer
remove_method(:gcd2)
def gcd2(int)
a = self.abs
b = int.abs
a, b = b, a if a < b
pd_a = a.prime_division
pd_b = b.prime_division
gcd = 1
for pair in pd_a
as = pd_b.assoc(pair[0])
if as
gcd *= as[0] ** [as[1], pair[1]].min
end
end
return gcd
def gcd2(other)
min = self.abs
max = other.abs
min, max = max % min, min while min > 0
max
end
def Integer.from_prime_division(pd)
value = 1
for prime, index in pd
@ -68,34 +57,54 @@ end
class Prime
include Enumerable
# These are included as class variables to cache them for later uses. If memory
# usage is a problem, they can be put in Prime#initialize as instance variables.
def initialize
@seed = 1
@primes = []
@counts = []
# There must be no primes between @@primes[-1] and @@next_to_check.
@@primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101]
# @@next_to_check % 6 must be 1.
@@next_to_check = 103 # @@primes[-1] - @@primes[-1] % 6 + 7
@@ulticheck_index = 3 # @@primes.index(@@primes.reverse.find {|n|
# n < Math.sqrt(@@next_to_check) })
@@ulticheck_next_squared = 121 # @@primes[@@ulticheck_index + 1] ** 2
class << self
# Return the prime cache.
def cache
return @@primes
end
alias primes cache
alias primes_so_far cache
end
def initialize
@index = -1
end
# Return primes given by this instance so far.
def primes
return @@primes[0, @index + 1]
end
alias primes_so_far primes
def succ
i = -1
size = @primes.size
while i < size
if i == -1
@seed += 1
i += 1
else
while @seed > @counts[i]
@counts[i] += @primes[i]
end
if @seed != @counts[i]
i += 1
else
i = -1
end
@index += 1
while @index >= @@primes.length
# Only check for prime factors up to the square root of the potential primes,
# but without the performance hit of an actual square root calculation.
if @@next_to_check + 4 > @@ulticheck_next_squared
@@ulticheck_index += 1
@@ulticheck_next_squared = @@primes.at(@@ulticheck_index + 1) ** 2
end
# Only check numbers congruent to one and five, modulo six. All others
# are divisible by two or three. This also allows us to skip checking against
# two and three.
@@primes.push @@next_to_check if @@primes[2..@@ulticheck_index].find {|prime| @@next_to_check % prime == 0 }.nil?
@@next_to_check += 4
@@primes.push @@next_to_check if @@primes[2..@@ulticheck_index].find {|prime| @@next_to_check % prime == 0 }.nil?
@@next_to_check += 2
end
@primes.push @seed
@counts.push @seed + @seed
return @seed
return @@primes[@index]
end
alias next succ