Your comments would be reasonable if this were destined for a library,
but I haven't even finished checking it (and probably won't since I've
switched to a simple zero elimination scheme). But this is a bit
specialized for a library...a library should probably deal with
arbitrary ints from 8 to 64 or 128 [but I don't think that the 128 bit
type is yet standard, only reserved]. I just thought that something
like that should be available, possibly along the lines of Python's pack
and unpack, and wondered where it was and what it was called.)
Additionally, I'm clearly not the best person to write the library
version, as I still have LOTS of trouble with D templates. And I have
not successfully wrapped my mind around D ranges...which is odd, because
neither Ruby nor Python ranges give me much trouble. Perhaps its the syntax.
As for " pure", "@safe", and "nothrow" ... I'd like to understand that I
COULD use those annotations. (The "in" I agree should be applied. I
understand that one.)
As for size_t for indexes...here I think we disagree. It would be a bad
mistake to use an index that size. I even considered using short or
ushort, but I ran into a comment awhile back saying that one should
never use those for local variables. This *can't* be an efficient
enough way that it would be appropriate to use it for a huge array...but
that should probably be documented if it were for a library. (If I were
to use size_t indexing, I'd want to modify things so that I could feed
it a file as input, and that's taking it well away from what I was
building it for: converting input to a redis database so that I could
feed it raw serial data streams without first converting it into human
readable formats. I wanted to make everything ASCII-7 binary data,
which, when I thought about it more, was overkill. All I need to do is
eliminate internal zeros, since C handles various extended character
formats by ignoring them.
I'm not clear what you mean by a "final switch". fBit must adopt
various different values during execution. If you mean it's the same as
a nest of if...else if ... statements, that's all I was really
expecting, but I thought switch was a bit more readable.
Binary literals would be more self-documenting, but would make the code
harder to read. If I'd though of them I might have used them...but
maybe not.
Output range? Here I'm not sure what you're suggesting, probably
because I don't understand D ranges.
The formatting got a bit messed up during pasting from the editor to the
mail message. I should have looked at it more carefully. My standard
says that unless the entire block is on a single line, the closing brace
should align with the opening brace. And I use tabs for spacing which
works quite well in the editor, but I *do* need to remember to convert
it to spaces before doing a cut and paste.
Thanks for your comments. I guess that means that there *isn't* a
standard function that does this.
Charles
On 12/06/2014 03:01 PM, bearophile via Digitalmars-d-learn wrote:
Charles Hixson:
byte[] x8to7 (ubyte[] bin)
Better to add some annotations, like pure, @safe, nothrow, if you can,
and to annotate the bin with an "in".
int fByte, fBit;
It's probably better to define them as size_t.
switch (fBit)
I think D doesn't yet allow this switch to be _meaningfully_ a final
switch.
b = bin[fByte] & 0x7f;
D allows binary number literals as 0b100110010101.
b ~= (b1 | b2);
Perhaps an output range is better?
if (b == 0) bout ~= 0x80;
else bout ~= b;
fBit = fBit + 7;
if (fBit > 7)
{ fByte++;
fBit -= 7;
The formatting seems a bit messy.
Bye,
bearophile
