Buffer Data Convert as Image Using OpenCV
Code
Code version v0.1
---------------------------------------------------------------------------------------------------------------------------
#include <tchar.h>
#include <stdio.h>
#include <strsafe.h>
HANDLE hSlot;
LPCTSTR SlotName = TEXT("\\\\.\\mailslot\\mailslot");
BOOL ReadSlot()
{
DWORD cbMessage, cMessage, cbRead;
BOOL fResult;
LPTSTR lpszBuffer;
TCHAR achID[80];
DWORD cAllMessages;
HANDLE hEvent;
OVERLAPPED ov;
cbMessage = cMessage = cbRead = 0;
hEvent = CreateEvent(NULL, FALSE, FALSE, TEXT("ExampleSlot"));
if (NULL == hEvent)
return FALSE;
ov.Offset = 0;
ov.OffsetHigh = 0;
ov.hEvent = hEvent;
fResult = GetMailslotInfo(hSlot, // mailslot handle
(LPDWORD)NULL, // no maximum message size
&cbMessage, // size of next message
&cMessage, // number of messages
(LPDWORD)NULL); // no read time-out
if (!fResult)
{
printf("GetMailslotInfo failed with %d.\n", GetLastError());
return FALSE;
}
if (cbMessage == MAILSLOT_NO_MESSAGE)
{
printf("Waiting for a message...\n");
return TRUE;
}
cAllMessages = cMessage;
while (cMessage != 0) // retrieve all messages
{
// Allocate memory for the message.
lpszBuffer = (LPTSTR)GlobalAlloc(GPTR,
lstrlen((LPTSTR)achID) * sizeof(TCHAR) + cbMessage);
if (NULL == lpszBuffer)
return FALSE;
lpszBuffer[0] = '\0';
fResult = ReadFile(hSlot,
lpszBuffer,
cbMessage,
&cbRead,
&ov);
if (!fResult)
{
printf("ReadFile failed with %d.\n", GetLastError());
GlobalFree((HGLOBAL)lpszBuffer);
return FALSE;
}
cv::Mat mat = cv::Mat(640, 640, CV_8UC3, cv::Scalar(0, 0, 0));
std::memcpy(mat.data, lpszBuffer, 640 * 640 * 3);
cv::imshow("YOURWINDOW", mat);
cv::waitKey(1);
GlobalFree((HGLOBAL)lpszBuffer);
fResult = GetMailslotInfo(hSlot, // mailslot handle
(LPDWORD)NULL, // no maximum message size
&cbMessage, // size of next message
&cMessage, // number of messages
(LPDWORD)NULL); // no read time-out
if (!fResult)
{
printf("GetMailslotInfo failed (%d)\n", GetLastError());
return FALSE;
}
}
CloseHandle(hEvent);
return TRUE;
}
BOOL WINAPI MakeSlot(LPCTSTR lpszSlotName)
{
hSlot = CreateMailslot(
lpszSlotName,
0,
MAILSLOT_WAIT_FOREVER,
(LPSECURITY_ATTRIBUTES)NULL);
if (hSlot == INVALID_HANDLE_VALUE) {
printf("CreateMailslot failed with %d\n", GetLastError());
return FALSE;
}
else
std::cout << "Mailslot created successfully.\n";
return TRUE;
}
int main()
{
MakeSlot(SlotName);
cv::namedWindow("YOURWINDOW", cv::WINDOW_AUTOSIZE);
while (true) {
ReadSlot();
}
}
// producer:
LPCTSTR SlotName = TEXT("\\\\.\\mailslot\\mailslot");
BOOL WriteSlot(HANDLE hSlot, LPCTSTR lpszMessage)
{
BOOL fResult;
DWORD cbWritten;
fResult = WriteFile(hSlot, lpszMessage,
(DWORD)(lstrlen(lpszMessage) + 1) * sizeof(TCHAR),
&cbWritten, (LPOVERLAPPED)NULL);
if (!fResult) {
printf("WriteFile failed with %d.\n", GetLastError());
return FALSE;
}
printf("Slot written to successfully.\n");
return TRUE;
}
cv::Mat mat =
cv::imread("C:\\Repos\\tmp\\decode\\images\\output_0664.jpg");
size_t sizeInBytes = mat.step[0] * mat.rows;
LPVOID lpBuffer = malloc(sizeInBytes);
HANDLE hFile;
hFile = CreateFile(SlotName, GENERIC_WRITE,
FILE_SHARE_READ,
(LPSECURITY_ATTRIBUTES)NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
(HANDLE)NULL);
if (hFile == INVALID_HANDLE_VALUE) {
printf("CreateFile failed with %d.\n",
GetLastError());
return FALSE;
}
DWORD bytesWritten;
memcpy(lpBuffer, &mat.data[0], sizeInBytes);
WriteFile(hFile, lpBuffer, sizeInBytes, &bytesWritten,
NULL);
CloseHandle(hFile); Code Version V0.2:-----------------------------------------------------------------------------------------------#include <tchar.h> #include <stdio.h> #include <strsafe.h> HANDLE hSlot; LPCTSTR SlotName = TEXT("\\\\.\\mailslot\\mailslot"); BOOL ReadSlot() { DWORD cbMessage, cMessage, cbRead; BOOL fResult; LPTSTR lpszBuffer; TCHAR achID[80]; DWORD cAllMessages; HANDLE hEvent; OVERLAPPED ov; cbMessage = cMessage = cbRead = 0; hEvent = CreateEvent(NULL, FALSE, FALSE, TEXT("ExampleSlot")); if (NULL == hEvent) return FALSE; ov.Offset = 0; ov.OffsetHigh = 0; ov.hEvent = hEvent; fResult = GetMailslotInfo(hSlot, // mailslot handle (LPDWORD)NULL, // no maximum message size &cbMessage, // size of next message &cMessage, // number of messages (LPDWORD)NULL); // no read time-out if (!fResult) { printf("GetMailslotInfo failed with %d.\n", GetLastError()); return FALSE; } if (cbMessage == MAILSLOT_NO_MESSAGE) { printf("Waiting for a message...\n"); return TRUE; } cAllMessages = cMessage; while (cMessage != 0) // retrieve all messages { // Allocate memory for the message. lpszBuffer = (LPTSTR)GlobalAlloc(GPTR, lstrlen((LPTSTR)achID) * sizeof(TCHAR) + cbMessage); if (NULL == lpszBuffer) return FALSE; lpszBuffer[0] = '\0'; fResult = ReadFile(hSlot, lpszBuffer, cbMessage, &cbRead, &ov); if (!fResult) { printf("ReadFile failed with %d.\n", GetLastError()); GlobalFree((HGLOBAL)lpszBuffer); return FALSE; } cv::Mat mat = cv::Mat(640, 640, CV_8UC3, cv::Scalar(0, 0, 0)); std::memcpy(mat.data, lpszBuffer, 640 * 640 * 3); cv::imshow("YOURWINDOW", mat); cv::waitKey(1); GlobalFree((HGLOBAL)lpszBuffer); fResult = GetMailslotInfo(hSlot, // mailslot handle (LPDWORD)NULL, // no maximum message size &cbMessage, // size of next message &cMessage, // number of messages (LPDWORD)NULL); // no read time-out if (!fResult) { printf("GetMailslotInfo failed (%d)\n", GetLastError()); return FALSE; } } CloseHandle(hEvent); return TRUE; } BOOL WINAPI MakeSlot(LPCTSTR lpszSlotName) { hSlot = CreateMailslot( lpszSlotName, 0, MAILSLOT_WAIT_FOREVER, (LPSECURITY_ATTRIBUTES)NULL); if (hSlot == INVALID_HANDLE_VALUE) { printf("CreateMailslot failed with %d\n", GetLastError()); return FALSE; } else std::cout << "Mailslot created successfully.\n"; return TRUE; } int main() { MakeSlot(SlotName); cv::namedWindow("YOURWINDOW", cv::WINDOW_AUTOSIZE); while (true) { ReadSlot(); } } // producer: LPCTSTR SlotName = TEXT("\\\\.\\mailslot\\mailslot"); BOOL WriteSlot(HANDLE hSlot, LPCTSTR lpszMessage) { BOOL fResult; DWORD cbWritten; fResult = WriteFile(hSlot, lpszMessage, (DWORD)(lstrlen(lpszMessage) + 1) * sizeof(TCHAR), &cbWritten, (LPOVERLAPPED)NULL); if (!fResult) { printf("WriteFile failed with %d.\n", GetLastError()); return FALSE; } printf("Slot written to successfully.\n"); return TRUE; } cv::Mat mat = cv::imread("C:\\Repos\\tmp\\decode\\images\\output_0664.jpg"); size_t sizeInBytes = mat.step[0] * mat.rows; LPVOID lpBuffer = malloc(sizeInBytes); HANDLE hFile; hFile = CreateFile(SlotName, GENERIC_WRITE, FILE_SHARE_READ, (LPSECURITY_ATTRIBUTES)NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, (HANDLE)NULL); if (hFile == INVALID_HANDLE_VALUE) { printf("CreateFile failed with %d.\n", GetLastError()); return FALSE; } DWORD bytesWritten; memcpy(lpBuffer, &mat.data[0], sizeInBytes); WriteFile(hFile, lpBuffer, sizeInBytes, &bytesWritten, NULL); CloseHandle(hFile);
