From: matz@... (Yukihiro Matsumoto)
Date: 2000-09-12T01:27:09+09:00
Subject: [ruby-talk:4850] Re: FEATURE REQUEST: Fixnum bitfields

Hi,

In message "[ruby-talk:4849] FEATURE REQUEST: Fixnum bitfields"
    on 00/09/12, Wayne Scott <wscott@ichips.intel.com> writes:

|why not:
|
|fixnum[bit,len]    access a bitfield in number
|bignum[bit,len]    access a bitfield in number

Do you mean 0xbabe[16,8] returns 0xba?
Hmm, is this useful?  Or just for completeness?

|fixnum[Range]      access a bitfield in number
|bignum[Range]      access a bitfield in number

Same as above.  I agree with your friend.  Persuade me.

|While I am on the subject of bitfields where is another question.
|Supose I read a series or raw 256 bit data chunks from a file into
|Strings.  How can I transfer them to Bignum's so i can do bitwise ORs
|and ANDs on them.  (I want to convert my CRC checksum generator for
|CPU caches from perl to Ruby.)

def bits2num(str)
  n = 0
  str.each_byte do |c|
    n <<= 8
    n |= c
  end
  n
end

							matz.