The goal is to control which types of users are allowed to perform which operations at the UI level. This code has been in place for a while; I just want to improve it a bit. The file which I am trying to improve should probably be auto-generated, but that would be too big of a change, so I seek a simpler solution.
A file which we shall call PermissionBits.h
has a bunch of these:
// Here names are mangled; for example XYZ_OP_A is:
// permission to operation A in category/context XYZ
// SCU64 = static const unsigned __int64
// Some namespaces utilize all 64 bits
// The actual values (as long as they are proper bit fields)
// do not matter - they are always used by name
namespace XYZPermissionBits
{
SCU64 XYZ_OP_A = 1UI64 << 0; // 1 = 0x0000000000000001
SCU64 XYZ_OP_B = 1UI64 << 1; // 2 = 0x0000000000000002
SCU64 XYZ_OP_C = 1UI64 << 2; // 4 = 0x0000000000000004
SCU64 XYZ_OP_C = 1UI64 << 3; // 8 = 0x0000000000000008
SCU64 XYZ_OP_D = 1UI64 << 4; // 16 = 0x0000000000000010
SCU64 XYZ_OP_E = 1UI64 << 5; // 32 = 0x0000000000000020
SCU64 XYZ_OP_F = 1UI64 << 6; // 64 = 0x0000000000000040
SCU64 XYZ_OP_G = 1UI64 << 7; // 128 = 0x0000000000000080
SCU64 XYZ_OP_H = 1UI64 << 8; // 256 = 0x0000000000000100
SCU64 XYZ_OP_I = 1UI64 << 9; // 512 = 0x0000000000000200
SCU64 XYZ_OP_J = 1UI64 << 10; // 1024 = 0x0000000000000400
SCU64 XYZ_OP_K = 1UI64 << 11; // 2048 = 0x0000000000000800
SCU64 XYZ_OP_L = 1UI64 << 12; // 4096 = 0x0000000000001000
}
Even with the help of 1UI64 << <numBits>;
shortcut there are still problems, as coders create flags with duplicate values, make typos, etc.
Ideally I would like a macro which can be nicely formatted and look like:
BITFIELDS_FOR_NAMESPACE(
//*************** <<== I want to make the namespace name more vivid
XYZPermissionBits,
//*************** <<== somehow if that is possible. It is not a must-have.
XYZ_OP_A, // Being able to add a comment here would be nice, but not critical
XYZ_OP_B,
XYZ_OP_C,
XYZ_OP_D,
XYZ_OP_E,
XYZ_OP_F,
XYZ_OP_G,
XYZ_OP_H,
XYZ_OP_I,
XYZ_OP_J,
XYZ_OP_K,
XYZ_OP_L
)
I would like this macro be flexible and prevent me from entering less than 2 or more than 65 arguments - namespace name + 64 flags. Is it possible to do what I want or close to it, or should I resort to generated code? What other advice do you have?