[英]An efficient way to convert ByteData in Dart to unsigned char* in C++?
I'm doing it in this way:我是这样做的:
Pointer<Uint8> _byteDataToPointer(ByteData byteData) {
final uint8List = byteData.buffer.asUint8List();
final length = uint8List.lengthInBytes;
final result = allocate<Uint8>(count: length);
for (var i = 0; i < length; ++i) {
result[i] = uint8List[i];
}
return result;
}
Is there a more efficient way like JNIEnv::GetByteArrayRegion in JNI?在 JNI 中有没有像JNIEnv::GetByteArrayRegion这样更有效的方法?
Thank you very much!非常感谢!
This is always going to involve a copy, so is there something more efficient than your for loop?这总是会涉及一个副本,所以有什么比你的 for 循环更有效的吗? Maybe.
也许。
After allocating your Uint8Pointer
use asTypedList
to convert it to a Uint8List
.分配
Uint8Pointer
使用asTypedList
将其转换为Uint8List
。 Now you have access to its copy primitive like setAll
and setRange
to copy from the source to the destination.现在您可以访问其复制原语,如
setAll
和setRange
以从源复制到目标。
What's the original source of the ByteData
? ByteData
的原始来源是ByteData
? If you knew the size in advance, could you allocate the Uint8Pointer first, convert to typed data and then read directly into that?如果你事先知道大小,你能不能先分配Uint8Pointer,转换成类型数据,然后直接读进去?
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