Re: BOOL array
Re: BOOL array
- Subject: Re: BOOL array
- From: Peter N Lewis <email@hidden>
- Date: Thu, 11 Sep 2008 22:03:43 +0800
At 14:22 +0100 11/9/08, dreamcat7 wrote:
On 11 Sep 2008, at 13:08, Jean-Daniel Dupas wrote:
And it probably does it better as it will not waste 7 bits for each option.
No, in a CFBitVector there is 4-bytes for each bit.
CFBit
A binary value of either 0 or 1.
typedef UInt32 CFBit;
The CFBit type is used only for parameters, it is not indicitive of
how the bits are actually stored.
You can see the source code for a version of CFBitVector at
<http://src.gnu-darwin.org/DarwinSourceArchive/expanded/CF/CF-299/Collections.subproj/CFBitVector.c>
/* The bucket type must be unsigned, at least one byte in size, and a
power of 2 in number of bits; bits are numbered from 0 from left to
right (bit 0 is the most significant) */
__CF_BITS_PER_BYTE = 8
__CF_BITS_PER_BUCKET = (__CF_BITS_PER_BYTE * sizeof(__CFBitVectorBucket))
etc.
Of course there is no guarentee as to the storage, but I think it's
safe to assume a guarantee of a little more than 1 bit per BOOL.
Enjoy,
Peter.
--
Keyboard Maestro 3 Now Available!
Now With Status Menu triggers!
Keyboard Maestro <http://www.keyboardmaestro.com/> Macros for your Mac
<http://www.stairways.com/> <http://download.stairways.com/>
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden