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Move docs for Integer#bit_length [ci skip]

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Alan Wu 2020-12-14 20:01:55 -05:00
parent befa24488c
commit c59b9a8c0c
2 changed files with 41 additions and 45 deletions
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41
integer.rb
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@ -4,6 +4,47 @@ class Integer
Primitive.cexpr! 'rb_int_abs(self)'
end
# call-seq:
# int.bit_length -> integer
#
# Returns the number of bits of the value of +int+.
#
# "Number of bits" means the bit position of the highest bit
# which is different from the sign bit
# (where the least significant bit has bit position 1).
# If there is no such bit (zero or minus one), zero is returned.
#
# I.e. this method returns <i>ceil(log2(int < 0 ? -int : int+1))</i>.
#
# (-2**1000-1).bit_length #=> 1001
# (-2**1000).bit_length #=> 1000
# (-2**1000+1).bit_length #=> 1000
# (-2**12-1).bit_length #=> 13
# (-2**12).bit_length #=> 12
# (-2**12+1).bit_length #=> 12
# -0x101.bit_length #=> 9
# -0x100.bit_length #=> 8
# -0xff.bit_length #=> 8
# -2.bit_length #=> 1
# -1.bit_length #=> 0
# 0.bit_length #=> 0
# 1.bit_length #=> 1
# 0xff.bit_length #=> 8
# 0x100.bit_length #=> 9
# (2**12-1).bit_length #=> 12
# (2**12).bit_length #=> 13
# (2**12+1).bit_length #=> 13
# (2**1000-1).bit_length #=> 1000
# (2**1000).bit_length #=> 1001
# (2**1000+1).bit_length #=> 1001
#
# This method can be used to detect overflow in Array#pack as follows:
#
# if n.bit_length < 32
# [n].pack("l") # no overflow
# else
# raise "overflow"
# end
def bit_length
Primitive.attr! 'inline'
Primitive.cexpr! 'rb_int_bit_length(self)'

45
numeric.c
View file

@ -4890,51 +4890,6 @@ int_size(VALUE num)
return Qnil;
}
/*
* Document-method: Integer#bit_length
* call-seq:
* int.bit_length -> integer
*
* Returns the number of bits of the value of +int+.
*
* "Number of bits" means the bit position of the highest bit
* which is different from the sign bit
* (where the least significant bit has bit position 1).
* If there is no such bit (zero or minus one), zero is returned.
*
* I.e. this method returns <i>ceil(log2(int < 0 ? -int : int+1))</i>.
*
* (-2**1000-1).bit_length #=> 1001
* (-2**1000).bit_length #=> 1000
* (-2**1000+1).bit_length #=> 1000
* (-2**12-1).bit_length #=> 13
* (-2**12).bit_length #=> 12
* (-2**12+1).bit_length #=> 12
* -0x101.bit_length #=> 9
* -0x100.bit_length #=> 8
* -0xff.bit_length #=> 8
* -2.bit_length #=> 1
* -1.bit_length #=> 0
* 0.bit_length #=> 0
* 1.bit_length #=> 1
* 0xff.bit_length #=> 8
* 0x100.bit_length #=> 9
* (2**12-1).bit_length #=> 12
* (2**12).bit_length #=> 13
* (2**12+1).bit_length #=> 13
* (2**1000-1).bit_length #=> 1000
* (2**1000).bit_length #=> 1001
* (2**1000+1).bit_length #=> 1001
*
* This method can be used to detect overflow in Array#pack as follows:
*
* if n.bit_length < 32
* [n].pack("l") # no overflow
* else
* raise "overflow"
* end
*/
static VALUE
rb_fix_bit_length(VALUE fix)
{