Common C++ classes and routines used by my applications such as argument parser, IO and conversion utilities
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#include "./commandlineutils.h"
#include "./argumentparserprivate.h"
#include <iostream>
#include <string>
#ifndef PLATFORM_WINDOWS
#include <sys/ioctl.h>
#include <unistd.h>
#else
#include <fcntl.h>
#include <windows.h>
#endif
using namespace std;
namespace CppUtilities {
/*!
* \brief Prompts for confirmation displaying the specified \a message.
*/
bool confirmPrompt(const char *message, Response defaultResponse)
{
cout << message;
cout << ' ' << '[';
cout << (defaultResponse == Response::Yes ? 'Y' : 'y');
cout << '/' << (defaultResponse == Response::No ? 'N' : 'n');
cout << ']' << ' ';
cout.flush();
for (string line;;) {
getline(cin, line);
if (line == "y" || line == "Y" || (defaultResponse == Response::Yes && line.empty())) {
return true;
} else if (line == "n" || line == "N" || (defaultResponse == Response::No && line.empty())) {
return false;
} else {
cout << "Please enter [y] or [n]: ";
cout.flush();
}
}
}
/*!
* \brief Returns the current size of the terminal.
* \remarks Unknown members of the returned TerminalSize are set to zero.
*/
TerminalSize determineTerminalSize()
{
TerminalSize size;
#ifndef PLATFORM_WINDOWS
ioctl(STDOUT_FILENO, TIOCGWINSZ, reinterpret_cast<winsize *>(&size));
#else
CONSOLE_SCREEN_BUFFER_INFO consoleBufferInfo;
if (const HANDLE stdHandle = GetStdHandle(STD_OUTPUT_HANDLE)) {
GetConsoleScreenBufferInfo(stdHandle, &consoleBufferInfo);
if (consoleBufferInfo.dwSize.X > 0) {
size.columns = static_cast<unsigned short>(consoleBufferInfo.dwSize.X);
}
if (consoleBufferInfo.dwSize.Y > 0) {
size.rows = static_cast<unsigned short>(consoleBufferInfo.dwSize.Y);
}
}
#endif
return size;
}
#ifdef PLATFORM_WINDOWS
/*!
* \brief Closes stdout, stdin and stderr and stops the console.
* \remarks Internally used by startConsole() to close the console when the application exits.
*/
void stopConsole()
{
fclose(stdout);
fclose(stdin);
fclose(stderr);
if (auto *const consoleWindow = GetConsoleWindow()) {
PostMessage(consoleWindow, WM_KEYUP, VK_RETURN, 0);
FreeConsole();
}
}
/*!
* \brief Ensure the process has a console attached and sets its output code page to UTF-8.
* \remarks
* - Only available (and required) under Windows where otherwise stdout/stderr is not printed to the console (at
* least when using `cmd.exe`).
* - Used to start a console from a GUI application. Does *not* create a new console if the process already has one.
* - Closes the console automatically when the application exits.
* - It breaks redirecting stdout/stderr so this can be opted-out by setting the environment
* variable `ENABLE_CONSOLE=0` and/or `ENABLE_CP_UTF8=0`.
* \sa
* - https://docs.microsoft.com/en-us/windows/console/AttachConsole
* - https://docs.microsoft.com/en-us/windows/console/AllocConsole
* - https://docs.microsoft.com/en-us/windows/console/SetConsoleCP
* - https://docs.microsoft.com/en-us/windows/console/SetConsoleOutputCP
*/
void startConsole()
{
// attach to the parent process' console or allocate a new console if that's not possible
const auto consoleEnabled = isEnvVariableSet("ENABLE_CONSOLE");
if ((!consoleEnabled.has_value() || consoleEnabled.value()) && (AttachConsole(ATTACH_PARENT_PROCESS) || AllocConsole())) {
// redirect stdout
auto stdHandle = reinterpret_cast<intptr_t>(GetStdHandle(STD_OUTPUT_HANDLE));
auto conHandle = _open_osfhandle(stdHandle, _O_TEXT);
auto fp = _fdopen(conHandle, "w");
*stdout = *fp;
setvbuf(stdout, nullptr, _IONBF, 0);
// redirect stdin
stdHandle = reinterpret_cast<intptr_t>(GetStdHandle(STD_INPUT_HANDLE));
conHandle = _open_osfhandle(stdHandle, _O_TEXT);
fp = _fdopen(conHandle, "r");
*stdin = *fp;
setvbuf(stdin, nullptr, _IONBF, 0);
// redirect stderr
stdHandle = reinterpret_cast<intptr_t>(GetStdHandle(STD_ERROR_HANDLE));
conHandle = _open_osfhandle(stdHandle, _O_TEXT);
fp = _fdopen(conHandle, "w");
*stderr = *fp;
setvbuf(stderr, nullptr, _IONBF, 0);
// sync
ios::sync_with_stdio(true);
// ensure the console prompt is shown again when app terminates
atexit(stopConsole);
}
// set console character set to UTF-8
const auto utf8Enabled = isEnvVariableSet("ENABLE_CP_UTF8");
if (!utf8Enabled.has_value() || utf8Enabled.value()) {
SetConsoleCP(CP_UTF8);
SetConsoleOutputCP(CP_UTF8);
}
}
/*!
* \brief Convert command line arguments to UTF-8.
* \remarks Only available on Windows (on other platforms we can assume passed arguments are already UTF-8 encoded).
*/
pair<vector<unique_ptr<char[]>>, vector<char *>> convertArgsToUtf8()
{
pair<vector<unique_ptr<char[]>>, vector<char *>> res;
int argc;
LPWSTR *argv_w = CommandLineToArgvW(GetCommandLineW(), &argc);
if (!argv_w || argc <= 0) {
return res;
}
res.first.reserve(static_cast<size_t>(argc));
res.second.reserve(static_cast<size_t>(argc));
for (LPWSTR *i = argv_w, *end = argv_w + argc; i != end; ++i) {
int requiredSize = WideCharToMultiByte(CP_UTF8, 0, *i, -1, nullptr, 0, 0, 0);
if (requiredSize <= 0) {
break; // just stop on error
}
auto argv = make_unique<char[]>(static_cast<size_t>(requiredSize));
requiredSize = WideCharToMultiByte(CP_UTF8, 0, *i, -1, argv.get(), requiredSize, 0, 0);
if (requiredSize <= 0) {
break;
}
res.second.emplace_back(argv.get());
res.first.emplace_back(move(argv));
}
LocalFree(argv_w);
return res;
}
#endif
} // namespace CppUtilities