Numeric access to char[]

[nobody]

Peter Thomassen wrote:
> nobody schrieb am Dienstag, 22. August 2006 00:54:
>>> how is it possible to work on the numeric value of a char[]? I'm
>>> interested in bit shifting and arithmetic operations on the numeric
>>> value.
>> I am pretty sure you can just treat a char as a ubyte. The char type is 8
>> bits and unsigned. However if it makes it easier for you then you might
>> try this:
>>
>>    int main(char[][] args)
>>    {
>>      ubyte[] num1 = cast(ubyte) args[0];
>>    }
> 
> When casting to ubyte[], this works fine. But I actually meant the numeric
> value of char[], not the one of char. Do I need to construct it from the
> single chars, or can I, for example, right-shift a whole char[] by 1?
> 
> Peter

Sorry I misunderstood you! I am still not completely sure what you are after but 
I think it sounds likely you mean this:

   char[] ex = "azAZ";
   // 'a' = 65 = 01000001 (binary)
   // 'z' = 90 = 01011010 (binary)
   // 'A' = 97 = 01100001 (binary)
   // 'Z' = 122= 01111010 (binary)

   01000001 01011010 01100001 01111010

becomes (carries from one pos to the next)

   00100000 10101101 00110000 10111101

instead of (right 1s fall off)

   00100000 00101101 00110000 00111101

I am pretty sure the only likely candidate for that would have been std.bitarray 
but the docs don't include the shift operators:

http://digitalmars.com/d/phobos/std_bitarray.html

So you will have to do it manually. I would like to suggest that if you can pad 
the char[] to ensure its .length % 8 == 0 then you can cast it to a ulong and 
your shifting will be faster.