On 12/12/2012 07:22 PM, Jonathan M Davis wrote:
> On Wednesday, December 12, 2012 17:34:53 Ali Çehreli wrote:
>> (There must be an easier way of doing that. :))
>
> If you have a string that's really ASCII and you're _sure_ that it's only
> ASCII, then I'd suggest simply casting it to immutable(ubyte)[] and
operating
> on that with all range based functions. That way, no decoding occurs,
and you
> don't have to dup the string. If you want, you could also easily create a
> funtion called something like assumeASCII that did that cast in order
to make
> it more idiomatic (similar to std.exception.assumeUnique).
>
> - Jonathan M Davis
I like that. :)
Potentially, the function can check in debug compilation that a random
selection of characters are really ASCII. Similar to what the
constructor of std.range.SortedRange (used as assumeSorted) does:
https://github.com/D-Programming-Language/phobos/blob/master/std/range.d#L7015
struct SortedRange(Range, alias pred = "a < b")
if (isRandomAccessRange!Range)
{
// ...
// Undocummented because a clearer way to invoke is by calling
// assumeSorted.
this(Range input)
{
this._input = input;
if(!__ctfe)
debug
{
import std.random;
// Check the sortedness of the input
if (this._input.length < 2) return;
immutable size_t msb = bsr(this._input.length) + 1;
assert(msb > 0 && msb <= this._input.length);
immutable step = this._input.length / msb;
static MinstdRand gen;
immutable start = uniform(0, step, gen);
auto st = stride(this._input, step);
assert(isSorted!pred(st), text(st));
}
}
// ...
}
Ali
