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digitalmars.D.bugs - [Issue 11757] New: toHexString doesn't support dynamic array

reply d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=11757

           Summary: toHexString doesn't support dynamic array
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: pro.mathias.lang gmail.com



04:23:30 PST ---
import std.digest.md;
import std.digest.sha;

ubyte[]    hmac_md5(ubyte[] key, string msg)
{
    immutable auto blocksize = 64;
    if (key.length > blocksize)
        key = md5Of(key);
    if (key.length < blocksize)
        key.length = blocksize;
    ubyte[blocksize] okp = 0x5c;
    ubyte[blocksize] ikp = 0x36;
    for (size_t i = 0; i < blocksize; ++i)
        okp[i] ^= key[i];
    for (size_t i = 0; i < blocksize; ++i)
        ikp[i] ^= key[i];
    return md5Of(okp ~ md5Of(ikp ~ cast(ubyte[])(msg)));
}
ubyte[]    hmac_md5(string key, string msg)
{
    return hmac_md5(cast(ubyte[])(key), msg);
}

unittest {
    auto md5hmac = hmac_md5("key", "The quick brown fox jumps over the lazy
dog");
    assert(toHexString(md5hmac) == "80070713463E7749B90C2DC24911E275");
}


This unittest will fail (toHexString returns
'E0166C00000000000000000000000000'), but if you replace ubyte[] with ubyte[16]
-or auto-, it'll pass.
DMD 2.064.2

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next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=11757


bearophile_hugs eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs eml.cc






     return hmac_md5(cast(ubyte[])(key), msg);


Don't use cast() unless you know what you are doing.



 'E0166C00000000000000000000000000'), but if you replace ubyte[] with ubyte[16]
 -or auto-, it'll pass.


One advantage of the current design of toHexString() is that it can't fail,
because the type system makes its usage safe and correct for most situations.
(Unless you use cast() randomly).

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prev sibling next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=11757


Mathias LANG <pro.mathias.lang gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID



05:32:59 PST ---



 

     return hmac_md5(cast(ubyte[])(key), msg);


 
 Don't use cast() unless you know what you are doing.
 
 

 'E0166C00000000000000000000000000'), but if you replace ubyte[] with ubyte[16]
 -or auto-, it'll pass.


 
 One advantage of the current design of toHexString() is that it can't fail,
 because the type system makes its usage safe and correct for most situations.
 (Unless you use cast() randomly).


Fair enough. I'm just a beginner, with a C[++] background, so keeping in mind
that string == immutable(char[]), chars are UTF-8, and my string is pure ASCII,
I "just" expected it to work.
I'll close this as invalid so, but I wouldn't be against an enlightment of
what's going on (and how to convert a string to an ubyte safely).
Thanks bearophile !

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prev sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=11757







 Fair enough. I'm just a beginner, with a C[++] background, so keeping in mind
 that string == immutable(char[]), chars are UTF-8, and my string is pure ASCII,
 I "just" expected it to work.
 I'll close this as invalid so, but I wouldn't be against an enlightment of
 what's going on (and how to convert a string to an ubyte safely).


In D fixed-sized arrays are values. ubyte[16] is a value, it's 16 unsigned
bytes.

A string is a struct that contains two words: a length and a pointer to a
series of immutable chars.

When you have similar doubts or questions I suggest you to ask them in the
D.learn newsgroup.

Your D code has several problems. This is a fist try at improving your code,
but some small problems still need to be fixed:


import std.digest.md, std.digest.sha, std.string;

enum size_t blockSize = 64;
enum size_t digestSize = 16;

ubyte[digestSize] hmacMD5(in ubyte[blockSize] key, in ubyte[] msg)
pure nothrow {
    ubyte[key.length] okp = 0x5c;
    okp[] ^= key[];
    ubyte[key.length] ikp = 0x36;
    ikp[] ^= key[];

    // Heap allocations here:
    return md5Of(okp ~ md5Of(ikp ~ msg));
}

ubyte[digestSize] hmacMD5(in string key, in string msg)
pure nothrow {
    ubyte[blockSize] key2;

    if (key.length > blockSize)
        key2[0 .. digestSize] = key.md5Of;
    else if (key.length < blockSize)
        key2[0 .. key.length] = key[].representation;

    return hmacMD5(key2, msg.representation);
}

void main() {
    immutable r = hmacMD5("key", "The quick brown fox jumps over the lazy
dog");
    assert(r.toHexString == "80070713463E7749B90C2DC24911E275");
}

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