Expose array data as pointer

[jpnurmi]

Consider the aiString structure in Assimp:

struct aiString {
    uint32_t length;
    char data[1024];
};

While the ArrayHelper, that is generated for the data, does offer [] and []= operators for accessing and manipulating the data at each index one by one, it seems like it would be more useful to expose the array data as a pointer:

class aiString extends Struct {
  @Uint32()
  int length;

  Pointer<Int8> get data => Pointer<Int8>.fromAddress(addressOf.address + sizeOf<Uint32>());
}

Int8Pointer would not only offer the same operators, but would also let you have the data as a typed list view too. This struct here is extremely simple, though. Things might get hairy if there are holes/padding involved.

[jpnurmi]

Oh, and if dart:ffi had something like @Padding(1024), you could easily fill up the memory gap without having to generate 1024 x Int8.

[dcharkes]

Blocked by dart-lang/sdk#35763.

[maks]

@dcharkes is this still blocked given that dart-lang/sdk#35763 has been closed?

[dcharkes]

Shouldn't that generate the following now?

class aiString extends Struct {
  @Uint32()
  int length;

  Array<Int8> data;
}

Array already provides index access.

https://api.dart.dev/stable/2.14.1/dart-ffi/Array-class.html

Side note: exposing as Pointer would not work. Because the struct might be passed by value and live in Dart memory instead of C memory, in which case it is backed by a TypedData rather than a Pointer. Array wraps either of those.