libdart_openmvg/lib/util.dart

import 'dart:collection';
import 'dart:ffi';
import 'dart:io';
import "package:ffi/ffi.dart";

class Uint8FlexList extends ListBase<Uint8> {
  final List<Uint8> _list = [];
  Uint8FlexList();

  late Pointer<Uint8> pointer;

  @override
  Uint8 operator [](int index) => _list[index];

  set list(List<Uint8> l) {
    _list.removeWhere((element) => true);
    _list.addAll(l);
    Pointer<Uint8> p = pointer;
    pointer = calloc<Uint8>(l.length);
    for (int i = 0; i < _list.length; ++i) {
      pointer[i] = _list[i] as int;
    }
    calloc.free(p);
  }

  @override
  void operator []=(int index, Uint8 value) {
    if (index > _list.length) {
      // resize the pointer
      pointer = calloc<Uint8>(index - 1);
      for (int i = 0; i < _list.length; ++i) {
        pointer[i] = _list[i] as int;
      }
    }
    _list[index] = value;
    pointer[index] = value as int;
  }

  @override
  int get length => _list.length;

  @override
  set length(int newLength) {
    throw Error();
  }

  static fromList(List<Uint8> l) {
    final l2 = Uint8FlexList();
    l2.list = l;
    return l2;
  }
}

Uint8FlexList readUint8Ptr(File file) {
  return Uint8FlexList.fromList(file.readAsBytesSync().cast());
}