Re: bigEndian in std.bitmanip
On Thursday, 2 November 2023 at 11:29:05 UTC, Salih Dincer wrote: On Tuesday, 31 October 2023 at 14:43:43 UTC, Imperatorn wrote: It might make sense to change since little endian is the most common when it comes to hardware. But big endian is most common when it comes to networking. So I guess it depends on your view of what is most common. Interacting with your local hardware or networking. I realized that I had to make my prefer based on the most common. But I have to use Union. That's why I have to choose little.Endian. Because it is compatible with both Union and HexString. My test code works perfectly as seen below. I'm grateful to everyone who helped here and [on the other thread](https://forum.dlang.org/thread/ekpvajiablcfueyip...@forum.dlang.org). Nice to hear you found a solution. Little endian is *most common* in hardware but big endian is *most common* in networking, so defining a default endianness can be tricky.
Re: bigEndian in std.bitmanip
On Tuesday, 31 October 2023 at 14:43:43 UTC, Imperatorn wrote:
It might make sense to change since little endian is the most
common when it comes to hardware. But big endian is most common
when it comes to networking. So I guess it depends on your view
of what is most common. Interacting with your local hardware or
networking.
I realized that I had to make my prefer based on the most common.
But I have to use Union. That's why I have to choose
little.Endian. Because it is compatible with both Union and
HexString. My test code works perfectly as seen below. I'm
grateful to everyone who helped here and [on the other
thread](https://forum.dlang.org/thread/ekpvajiablcfueyip...@forum.dlang.org).
```d
enum sampleText = "Hello D!"; // length <= 8 char
void main()
{
//import sdb.string : UnionBytes;
mixin UnionBytes!size_t;
bytes.init = sampleText;
import std.digest: toHexString;
auto hexF = bytes.cell.toHexString;
assert(hexF == "48656C6C6F204421");
import std.string : format;
auto helloD = sampleText.format!"%(%02X%)";
assert(hexF == helloD);
import std.stdio;
bytes.code.writeln(": ", helloD); /* Prints:
2397076564600448328: 48656C6C6F204421 */
import std.conv : hexString;
static assert(sampleText == hexString!"48656C6C6F204421");
//import sdb.string : readBytes;
auto code = bytes.cell.readBytes!size_t;
assert(code == bytes.code);
bytes.init = code;
code.writeln(": ", bytes); /* Prints:
2397076564600448328: Hello D! */
assert(bytes[] == [72, 101, 108, 108, 111, 32, 68, 33]);
//import sdb.string : HexString
auto str = "0x";
auto hex = HexString!size_t(bytes.code);
hex.each!(chr => str ~= chr);
str.writeln; // 0x48656C6C6F204421
}
```
My core template (UnionBytes) is initialized like this, and
underneath I have the readBytes template, which also works with
static arrays:
```d
// ...
import std.range : front, popFront;
size_t i;
do // new version: range support
{
char chr; // default init: 0xFF
chr &= str.front; // masking
code |= T(chr) << (i * 8); // shifting
str.popFront; // next char
} while(++i < size);
}
auto opCast(Cast : T)() const
=> code;
auto opCast(Cast : string)() const
=> this.format!"%s";
auto toString(void delegate(in char[]) sink) const
=> sink.formattedWrite("%s", cast(char[])cell);
}
UnionBytes bytes; // for mixin
}
template readBytes(T, bool big = false, R)
{// pair endian version 2.1
import std.bitmanip;
static if(big) enum E = Endian.bigEndian;
else enum E = Endian.littleEndian;
import std.range : ElementType;
alias ET = ElementType!R;
auto readBytes(ref R dat)
{
auto data = cast(ET[])dat;
return read!(T, E)(data);
}
}
```
SDB@79
Re: bigEndian in std.bitmanip
On Tuesday, October 31, 2023 8:23:28 AM MDT Salih Dincer via Digitalmars-d-
learn wrote:
> On Tuesday, 31 October 2023 at 10:24:56 UTC, Jonathan M Davis
>
> wrote:
> > On Tuesday, October 31, 2023 4:09:53 AM MDT Salih Dincer via
> >
> > Digitalmars-d- learn wrote:
> >> Hello,
> >>
> >> Why isn't Endian.littleEndian the default setting for read() in
> >> std.bitmanip?
> >
> > Why would you expect little endian to be the default? The
> > typical thing to do when encoding integral values in a
> > platform-agnostic manner is to use big endian, not little
> > endian...
>
> Because when we create a structure with a Union, it does reverse
> insertion with according to the static array(bytes) index; I
> showed this above.
I fail to see what the situation with the union has to do with anything.
Sure, you can convert between an array of bytes and an int with a union if
you want to, but what that does is going to be dependent on your local
architecture. read and its related functions in std.bitmanip are
architecture-independent. So, they will convert from little endian or big
endian regardless of what your local architecture is. You would typically
use it on ranges of bytes that come from the network or from serialized
data. The most common scenario there is likely to be that they'll be in big
endian, because that's what platforma-independent binary formats typically
do, but you can explicitly tell read that the range is in little endian if
your range of bytes happens to be in little endian. Both scenarios can
occur, and it supports both. It just defaults to big endian, because that's
the more common scenario when dealing with binary formats.
> I also have a convenience template like this:
> ```d
> template readBytes(T, bool big = false, R)
> {// pair endian version 2.0
>import bop = std.bitmanip;
>
>static if(big)
> enum E = bop.Endian.bigEndian;
>else
> enum E = bop.Endian.littleEndian;
>
>auto readBytes(ref R dat)
> => bop.read!(T, E)(dat);
> }
> ```
> Sorry to give you extra engage because I already solved the
> problem with readBytes(). Thank you for your answer, but there is
> 1 more problem, or even 2! The read() in the library, which is
> 2nd function, conflicts with std.write. Yeah, there are many
> solutions to this, but what it does is just read bytes. However,
> you can insert 4 ushorts into one ulong.
>
> Don't you think the name of the function should be readBytes, not
> read? Because it doesn't work with any type other than ubyte[]!
D's module system makes it so that names do not need to be unique across
modules, and this is not the only case in Phobos where multiple modules use
the same function name. It's easy enough to import only the functions you're
using or to rename them via the import if you happen to be importing from
multiple modules containing functions with the same name. E.G. if you want
to do
std.bitmanip : readBytes = read;
then you can.
- Jonathan M Davis
Re: bigEndian in std.bitmanip
On Tuesday, 31 October 2023 at 10:09:53 UTC, Salih Dincer wrote:
Hello,
Why isn't Endian.littleEndian the default setting for read() in
std.bitmanip?
Okay, we can easily change this if we want (I could use enum LE
in the example) and I can also be reversed with
data.retro.array().
```d
void main()
{
import std.conv : hexString;
string helloD = hexString!"48656C6C6F204421";
// compile time converted literal string -ˆ
import std.string : format;
auto hexF = helloD.format!"%(%02X%)";
import std.digest: toHexString;
auto arr = cast(ubyte[])"Hello D!";
auto hex = arr.toHexString;
assert(hex == hexF);
import std.stdio : writeln;
hex.writeln(": ", helloD);
// 48656C6C6F204421: Hello D!
assert(helloD == "Hello D!");
auto data = arr.readBytes!size_t;
data.code.writeln(": ", data.bytes);
// 2397076564600448328: Hello D!
}
template readBytes(T, R)
{
union Bytes
{
T code;
char[T.sizeof] bytes;
}
import std.bitmanip;
enum LE = Endian.littleEndian;
auto readBytes(ref R data)
{
import std.range : retro, array;
auto reverse = data.retro.array;
return Bytes(reverse.read!T);
}
}
```
However, I think it is not compatible with Union. Thanks...
SDB@79
It might make sense to change since little endian is the most
common when it comes to hardware. But big endian is most common
when it comes to networking. So I guess it depends on your view
of what is most common. Interacting with your local hardware or
networking.
Re: bigEndian in std.bitmanip
On Tuesday, 31 October 2023 at 10:24:56 UTC, Jonathan M Davis
wrote:
On Tuesday, October 31, 2023 4:09:53 AM MDT Salih Dincer via
Digitalmars-d- learn wrote:
Hello,
Why isn't Endian.littleEndian the default setting for read() in
std.bitmanip?
Why would you expect little endian to be the default? The
typical thing to do when encoding integral values in a
platform-agnostic manner is to use big endian, not little
endian...
Because when we create a structure with a Union, it does reverse
insertion with according to the static array(bytes) index; I
showed this above. I also have a convenience template like this:
```d
template readBytes(T, bool big = false, R)
{// pair endian version 2.0
import bop = std.bitmanip;
static if(big)
enum E = bop.Endian.bigEndian;
else
enum E = bop.Endian.littleEndian;
auto readBytes(ref R dat)
=> bop.read!(T, E)(dat);
}
```
Sorry to give you extra engage because I already solved the
problem with readBytes(). Thank you for your answer, but there is
1 more problem, or even 2! The read() in the library, which is
2nd function, conflicts with std.write. Yeah, there are many
solutions to this, but what it does is just read bytes. However,
you can insert 4 ushorts into one ulong.
Don't you think the name of the function should be readBytes, not
read? Because it doesn't work with any type other than ubyte[]!
SDB@79
Re: bigEndian in std.bitmanip
On Tuesday, October 31, 2023 4:09:53 AM MDT Salih Dincer via Digitalmars-d- learn wrote: > Hello, > > Why isn't Endian.littleEndian the default setting for read() in > std.bitmanip? Why would you expect little endian to be the default? The typical thing to do when encoding integral values in a platform-agnostic manner is to use big endian, not little endian. Either way, it supports both big endian and little endian, so if your use case requires little endian, you can do that. You just have to specifiy the endianness, and if you find that to be too verbose, you can create a wrapper to use in your own code. - Jonathan M Davis
bigEndian in std.bitmanip
Hello,
Why isn't Endian.littleEndian the default setting for read() in
std.bitmanip?
Okay, we can easily change this if we want (I could use enum LE
in the example) and I can also be reversed with
data.retro.array().
```d
void main()
{
import std.conv : hexString;
string helloD = hexString!"48656C6C6F204421";
// compile time converted literal string -ˆ
import std.string : format;
auto hexF = helloD.format!"%(%02X%)";
import std.digest: toHexString;
auto arr = cast(ubyte[])"Hello D!";
auto hex = arr.toHexString;
assert(hex == hexF);
import std.stdio : writeln;
hex.writeln(": ", helloD);
// 48656C6C6F204421: Hello D!
assert(helloD == "Hello D!");
auto data = arr.readBytes!size_t;
data.code.writeln(": ", data.bytes);
// 2397076564600448328: Hello D!
}
template readBytes(T, R)
{
union Bytes
{
T code;
char[T.sizeof] bytes;
}
import std.bitmanip;
enum LE = Endian.littleEndian;
auto readBytes(ref R data)
{
import std.range : retro, array;
auto reverse = data.retro.array;
return Bytes(reverse.read!T);
}
}
```
However, I think it is not compatible with Union. Thanks...
SDB@79
