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* numeric.c (fix_pow): integer power calculation: 0**n => 0,
1**n => 1, -1**n => 1 (n: even) / -1 (n: odd). * test/ruby/test_fixnum.rb (TestFixnum::test_pow): update test suite. pow(-3, 2^64) gives NaN when pow(3, 2^64) gives Inf. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@12808 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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3 changed files with 45 additions and 6 deletions
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@ -1,3 +1,11 @@
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Tue Jul 17 00:50:53 2007 Yukihiro Matsumoto <matz@ruby-lang.org>
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* numeric.c (fix_pow): integer power calculation: 0**n => 0,
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1**n => 1, -1**n => 1 (n: even) / -1 (n: odd).
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* test/ruby/test_fixnum.rb (TestFixnum::test_pow): update test
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suite. pow(-3, 2^64) gives NaN when pow(3, 2^64) gives Inf.
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Mon Jul 16 23:07:51 2007 Yukihiro Matsumoto <matz@ruby-lang.org>
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* lib/base64.rb (Base64::b64encode): should not specify /o option
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41
numeric.c
41
numeric.c
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@ -2218,6 +2218,15 @@ int_pow(x, y)
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return LONG2NUM(z);
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}
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static VALUE
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int_even_p(VALUE num)
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{
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if (rb_funcall(num, '%', 1, INT2FIX(2)) == INT2FIX(0)) {
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return Qtrue;
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}
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return Qfalse;
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}
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/*
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* call-seq:
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* fix ** other => Numeric
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@ -2234,23 +2243,45 @@ static VALUE
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fix_pow(x, y)
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VALUE x, y;
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{
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long a = FIX2LONG(x);
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if (FIXNUM_P(y)) {
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long a, b;
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long b;
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b = FIX2LONG(y);
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if (b == 0) return INT2FIX(1);
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if (b == 1) return x;
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a = FIX2LONG(x);
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if (a == 0) return INT2FIX(0);
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if (a == 1) return INT2FIX(1);
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if (a == -1) {
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if (b % 2 == 0)
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return INT2FIX(1);
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else
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return INT2FIX(-1);
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}
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if (b > 0) {
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return int_pow(a, b);
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}
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return rb_float_new(pow((double)a, (double)b));
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} else if (TYPE(y) == T_FLOAT) {
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long a = FIX2LONG(x);
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return rb_float_new(pow((double)a, RFLOAT(y)->value));
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}
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return rb_num_coerce_bin(x, y);
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switch (TYPE(y)) {
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case T_BIGNUM:
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if (a == 0) return INT2FIX(0);
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if (a == 1) return INT2FIX(1);
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if (a == -1) {
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if (int_even_p(y)) return INT2FIX(1);
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else return INT2FIX(-1);
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}
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x = rb_int2big(FIX2LONG(x));
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return rb_big_pow(x, y);
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case T_FLOAT:
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if (a == 0) return rb_float_new(0.0);
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if (a == 1) return rb_float_new(1.0);
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return rb_float_new(pow((double)a, RFLOAT(y)->value));
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default:
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return rb_num_coerce_bin(x, y);
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}
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}
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/*
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@ -12,7 +12,7 @@ class TestFixnum < Test::Unit::TestCase
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def test_pow
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[1, 2, 2**64, 2**63*3, 2**64*3].each do |y|
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[1, 3].each do |x|
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[-1, 0, 1].each do |x|
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z1 = x**y
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z2 = (-x)**y
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if y % 2 == 1
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