C# - 从两个 Int32 生成一个 Int64

Question

C# 中是否有一个函数接受两个 32 位整数 (int) 并返回一个 64 位整数 (long)？

听起来应该有一个简单的方法来做到这一点，但我找不到解决方案。

Answer 1

尝试以下操作

public long MakeLong(int left, int right) {
  //implicit conversion of left to a long
  long res = left;

  //shift the bits creating an empty space on the right
  // ex: 0x0000CFFF becomes 0xCFFF0000
  res = (res << 32);

  //combine the bits on the right with the previous value
  // ex: 0xCFFF0000 | 0x0000ABCD becomes 0xCFFFABCD
  res = res | (long)(uint)right; //uint first to prevent loss of signed bit

  //return the combined result
  return res;
}