Added functions to retrieve terminal width

include/indicators/terminal_size.hpp

@@ -0,0 +1,63 @@
+/*
+Activity Indicators for Modern C++
+https://github.com/p-ranav/indicators
+
+Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+SPDX-License-Identifier: MIT
+Copyright (c) 2019 Pranav Srinivas Kumar <pranav.srinivas.kumar@gmail.com>.
+
+Permission is hereby  granted, free of charge, to any  person obtaining a copy
+of this software and associated  documentation files (the "Software"), to deal
+in the Software  without restriction, including without  limitation the rights
+to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
+copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
+IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
+FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
+AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
+LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+#pragma once
+#include <utility>
+
+namespace indicators {
+
+#if defined(_MSC_VER)
+#include <windows.h>
+
+std::pair<size_t, size_t> terminal_size() {
+    CONSOLE_SCREEN_BUFFER_INFO csbi;
+    int columns, rows;
+    GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi);
+    columns = csbi.srWindow.Right - csbi.srWindow.Left + 1;
+    rows = csbi.srWindow.Bottom - csbi.srWindow.Top + 1;
+    return {static_cast<size_t>(rows), static_cast<size_t>(cols)};
+}
+
+size_t terminal_width() {
+    return terminal_size().second;
+}
+
+#else
+#include <sys/ioctl.h> //ioctl() and TIOCGWINSZ
+#include <unistd.h> // for STDOUT_FILENO
+
+std::pair<size_t, size_t> terminal_size() {
+    struct winsize size;
+    ioctl(STDOUT_FILENO, TIOCGWINSZ, &size);
+    return {static_cast<size_t>(size.ws_row), static_cast<size_t>(size.ws_col)};
+}
+
+size_t terminal_width() {
+    return terminal_size().second;
+}
+#endif
+
+}