On Thursday, 17 March 2022 at 11:36:40 UTC, Patrick Schluter
wrote:
On Monday, 14 March 2022 at 09:40:00 UTC, zhad3 wrote:
Hey everyone, I am in need of some help. I have written this
Windows CP949 encoding table
https://github.com/zhad3/zencoding/blob/main/windows949/source/zencoding/windows949/table.d which is used to convert CP949 to UTF-16.
After some research about how to initialize immutable
associative arrays people suggested using `shared static
this()`. So far this worked for me, but I recently discovered
that DMD cannot compile this in release mode with
optimizations.
`dub build --build=release` or `dmd` with `-release -O` fails:
```
code windows949
function
zencoding.windows949.fromWindows949!(immutable(ubyte)[]).fromWindows949
code table
function zencoding.windows949.table._sharedStaticCtor_L29_C1
dmd failed with exit code -11.
```
I usually compile my projects using LDC where this works fine,
but I don't want to force others to use LDC because of this
one problem.
Hence I'd like to ask on how to change the code so that it
compiles on DMD in release mode (with optimizations). I
thought about having a computational algorithm instead of an
encoding table but sadly I could not find any references in
that regard. Apparently encoding tables seem to be the
standard.
Why not use a simple static array (not an associative array).
Where the values are indexed on `key - min(keys)`. Even with
the holes in the keys (i.e. keys that do not have corresponding
values) it will be smaller that the constructed associative
array? The lookup is also faster.
Something akin to
```d
auto lookup(ushort key)
{
return cp949[key-0x8141];
}
immutable ushort[0xFDFE-0x8141+1] cp949 = [
0x8141-0x8141: 0xAC02,
0x8142-0x8141: 0xAC03,
0x8143-0x8141: 0xAC05,
0x8144-0x8141: 0xAC06,
0x8145-0x8141: 0xAC0B,
0x8146-0x8141: 0xAC0C,
0x8147-0x8141: 0xAC0D,
0x8148-0x8141: 0xAC0E,
0x8149-0x8141: 0xAC0F,
0x814A-0x8141: 0xAC18,
0x814B-0x8141: 0xAC1E,
0x814C-0x8141: 0xAC1F,
0x814D-0x8141: 0xAC21,
0x814E-0x8141: 0xAC22,
0x814F-0x8141: 0xAC23,
0x8150-0x8141: 0xAC25,
0x8151-0x8141: 0xAC26,
0x8152-0x8141: 0xAC27,
0x8153-0x8141: 0xAC28,
0x8154-0x8141: 0xAC29,
0x8155-0x8141: 0xAC2A,
0x8156-0x8141: 0xAC2B,
0x8157-0x8141: 0xAC2E,
0x8158-0x8141: 0xAC32,
0x8159-0x8141: 0xAC33,
0x815A-0x8141: 0xAC34,
0x8161-0x8141: 0xAC35,
0x8162-0x8141: 0xAC36,
0x8163-0x8141: 0xAC37,
...
0xFDFA-0x8141: 0x72A7,
0xFDFB-0x8141: 0x79A7,
0xFDFC-0x8141: 0x7A00,
0xFDFD-0x8141: 0x7FB2,
0xFDFE-0x8141: 0x8A70,
];
```
