bitflags

How to pick bitflag values?

I have a set of options, some orthogonal (can be combined in any combination), some exclusive (only one from the set is allowed), and need to pick a set of enum values so that they can be combined with bit-wise or and extracted with bit-wise and. I would prefer that or-ing invalid combination would be detectable. Are there any tools for...

Enum bitfield container class

Im trying to write a small class to better understand bit flags in c++. But something isnt working out. It prints the wrong values. Where is the problem? Have I misunderstood how to add flags? Or check if the bit field has them? Heres the code: #include <iostream> enum flag { A = 1, B = 2, C = 4 }; class Holder { public: Hold...

#defined bitflags and enums - peaceful coexistence in "c"

I have just discovered the joy of bitflags. I have several questions related to "best-practices" regarding the use of bitflags in C. I learned everything from various examples I found on the web but still have questions. In order to save space, I am using a single 32bit integer field in a struct (A->flag) to represent several different ...

Bitflag enums in C++

Using enums for storing bitflags in C++ is a bit troublesome, since once the enum values are ORed they loose their enum-type, which causes errors without explicit casting. The accepted answer for this question suggests overloading the | operator: FlagsSet operator|(FlagsSet a, FlagsSet b) { return FlagsSet(int(a) | int(b)); } ...

How to calculate Bit Flag in javascript?

im writing a free tool for SEO... implementing an api from seomoz and the flags look like this URL Metric,Bit Flag Title,1 URL,4 Subdomain,8 Root Domain,16 External Links,32 Links,2048 mozRank,16384 mozTrust,131072 these are just a few but i dont know how to calculate the proper bit flag in javascript... is it just an OR of all the in...

What to name an array of flags?

I have a project where lots of the objects hold state by maintaining simple boolean flags. There are lots of these, so I maintain them within a uint32_t and use bit masking. There are now so many flags to keep track of, I've created an abstraction for them (just a class wrapping the uint32_t) with set(), clear(), etc. My question: Wha...

Is there a name for the technique of using base-2 numbers to encode a list of unique options?

Apologies for the rather vague nature of this question, I've never formally been taught programming and Google is rather useless to a self-help guy like me in this case as the key words are pretty ambiguous. I am writing a couple of functions that encode and decode a list of options into a Long so they can easily be passed around the ap...

Why does [Flag]'d enums start at 0 and increment by 1?

Edit: It seems most people misunderstood my question. I know how enum works, and I know binary. I'm wondering why the enums with the [Flags] attribute is designed the way it is. Original post: This might be a duplicate, but I didn't find any other posts, so here goes. I bet there has been some good rationale behind it, I just find it...

Actual uses of bit flags in .NET framework

Was looking at how enums can be used as bit flags by decorating them with the flags attribute and bitwize operators (see below). Are there any places in the .NET framework that this pattern is used? I like this but want to see some more real life examples [Flags] enum Days2 : int { None = 0x0, Sunday = 0x1, Monday = 0x2, Tuesd...

How should I represent a bit flags int field in django admin?

I have a data model with a bitfield defined something like this: alter table MemberFlags add column title varchar(50) not null default ''; alter table MemberFlags add column value integer( 3) not null default 0; insert into MemberFlags (title, value) values ("Blacklisted", 1), ("Special Guest", 2), ("A...