add fromHexString

[Tynukua]

As I understood Phobos does not contain any functions for converting text strings to byte array

hexString - template(not usable in runtime parse, to - cannot convert into byte array

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[Tynukua]

Just a high-level observation: having toDigest return a range would avoid the gc allocation.

I don't get you It already does not contains GC allocation for static arrays

[RazvanN7]

I don't get you

The first overload allocates with the gcc. My point was that toDigestImpl may return a range that lazily computes the bytes when needed. Isn't that possible?

[Tynukua]

I don't get you

The first overload allocates with the gcc. My point was that toDigestImpl may return a range that lazily computes the bytes when needed. Isn't that possible?

Do you mean I should calculate the count of bytes to allocate more accurately?

[RazvanN7]

No, I mean you could implement a ByteRange that lazily computes the bytes:

struct ByteRange
{
      string hexString;    // stores a reference to the hex string that needs to be digested
      size_t pos;

      bool empty() { return pos == hexString; }
      ubyte front() { /* compute the next byte to be returned */ }
      void popFront() {/* advance `pos` to the next hex number */}

      // maybe add other range primitives as well to make it a more powerful range
}

Then toDigest will return such a range and no gc allocation will be required. I noticed that other digest functions do not make use of ranges, however, I do not know if it is anything preventing them for doing so or people just didn't think about this. What do you think @atilaneves ?

[atilaneves]

In all likelihood they were written ages ago when allocating was all the rage. I don't think repeating the mistakes of the past makes sense.

[RazvanN7]

@atilaneves Do you think this is a worthwhile addition?

[Tynukua]

@atilaneves i updated PR now it contains only generator

[atilaneves]

As I understood Phobos does not contain any functions for converting text strings to byte array

hexString - template(not usable in runtime parse, to - cannot convert into byte array

Why can't they convert to a byte array?

[Tynukua]

As I understood Phobos does not contain any functions for converting text strings to byte array hexString - template(not usable in runtime parse, to - cannot convert into byte array

Why can't they convert to a byte array?

Actually it's possible by to, but u need chunk your hexstring https://forum.dlang.org/thread/[email protected]

[ibuclaw]

Where does this sit now with compiler support for casting to arrays?

https://dlang.org/changelog/pending.html#dmd.hexstring-cast

I think it was always possible to cast them to a byte array, which gets its range interface from std.array.

[atilaneves]

As I understood Phobos does not contain any functions for converting text strings to byte array hexString - template(not usable in runtime parse, to - cannot convert into byte array

Why can't they convert to a byte array?

Actually it's possible by to, but u need chunk your hexstring https://forum.dlang.org/thread/[email protected]

Why isn't the implementation in this PR the one using chunk in the forum, then?

[Tynukua]

Where does this sit now with compiler support for casting to arrays?

https://dlang.org/changelog/pending.html#dmd.hexstring-cast

I think it was always possible to cast them to a byte array, which gets its range interface from std.array.

it's compiler time feature sometimes you need proceed with hex string in runtime

[Tynukua]

Why isn't the implementation in this PR the one using chunk in the forum, then?

I thought @nogc solution will be better, but now i m not sure Have u any suggestions what implementation is better for std?

[atilaneves]

Why isn't the implementation in this PR the one using chunk in the forum, then?

I thought @nogc solution will be better, but now i m not sure Have u any suggestions what implementation is better for std?

Unless I'm missing something, the only thing that isn't @nogc in the solution in the forum is .array. Leave that out, and there's the implementation. Users can call .array if they want to.

[Tynukua]

Unless I'm missing something, the only thing that isn't @nogc in the solution in the forum is .array. Leave that out, and there's the implementation. Users can call .array if they want to.

.array part only in example...