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Simple calculations for working with lat/lon and km distance?
...> CLLocation {
let latDistance = (Double(arc4random()) / Double(UInt32.max)) * offset * 2.0 - offset
let longDistanceMax = sqrt(offset * offset - latDistance * latDistance)
let longDistance = (Double(arc4random()) / Double(UInt32.max)) * longDistanceMax * 2.0 - longDistanc...
In C/C++ what's the simplest way to reverse the order of bits in a byte?
... 0x4, 0xc, 0x2, 0xa, 0x6, 0xe,
0x1, 0x9, 0x5, 0xd, 0x3, 0xb, 0x7, 0xf, };
uint8_t reverse(uint8_t n) {
// Reverse the top and bottom nibble then swap them.
return (lookup[n&0b1111] << 4) | lookup[n>>4];
}
// Detailed breakdown of the math
// + lookup reverse of bottom nibble...
Creating a BLOB from a Base64 string in JavaScript
...his array of byte values into a real typed byte array by passing it to the Uint8Array constructor.
const byteArray = new Uint8Array(byteNumbers);
This in turn can be converted to a BLOB by wrapping it in an array and passing it to the Blob constructor.
const blob = new Blob([byteArray], {type: c...
How can I programmatically generate keypress events in C#?
..."user32.dll")]
public static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, uint dwExtraInfo);
sample code is given below:
const int VK_UP = 0x26; //up key
const int VK_DOWN = 0x28; //down key
const int VK_LEFT = 0x25;
const int VK_RIGHT = 0x27;
const uint KEYEVENTF_KEYUP = 0x0002;
...
How to check file MIME type with javascript before upload?
... = new FileReader();
fileReader.onloadend = function(e) {
var arr = (new Uint8Array(e.target.result)).subarray(0, 4);
var header = "";
for(var i = 0; i < arr.length; i++) {
header += arr[i].toString(16);
}
console.log(header);
// Check the file signature against known types
};
...
How do I shutdown, restart, or log off Windows via a bat file?
...ctual function signature for ExitWindowsEx is:
BOOL WINAPI ExitWindowsEx(UINT uFlags, DWORD dwReserved);
in 2011: "Throwing garbage on the sidewalk: The sad history of the rundll32 program"
And to make it crystal-clear:
in 2013 "What's the guidance on when to use rundll32? Easy: Don't use i...
Most common C# bitwise operations on enums
...umerable.Range(0, 64)
.Where(bit => ((flags.GetTypeCode() == TypeCode.UInt64 ? (long)(ulong)flags : Convert.ToInt64(flags)) & (1L << bit)) != 0)
.Select(bit => Enum.ToObject(flags.GetType(), 1L << bit))`
Enums.NET flags.GetFlags()
I'm trying to get these improvements i...
MFC CListCtrl使用方法详解 - C/C++ - 清泛网 - 专注C/C++及内核技术
...info.pt = point;
lvinfo.flags = LVHT_ABOVE;
UINT nFlag;
int nItem = m_list.HitTest(point, &nFlag);
//判断是否点在checkbox上
if(nFlag == LVHT_ONITEMSTATEICON)
{
AfxMessageBox("点在listctrl的check...
Getting a slice of keys from a map
...eysAppend function, you can set the capacity of the keys array with make([]uint64, 0, len(m)), which drastically changed the performance of that function for me.
– keithbhunter
Apr 1 '19 at 15:59
...
MFC中通过Tooltip类实现悬浮鼠标显示提示信息 - C/C++ - 清泛网 - 专注C/C++及内核技术
...一个函数用于动态提供显示内容，其原型为 BOOL SetTipText(UINT id, NMHDR *pTTTStruct, LRESULT *pResult)，下面的代码可以根据传入的参数判定应该显示的内容。
BOOL CWndYour::SetTipText(UINT id, NMHDR *pTTTStruct, LRESULT *pResult)
{
TOOLTIPTEXT *pTT...