initial commit, 4.5 stable

thirdparty/sdl/core/unix/SDL_poll.c

@@ -0,0 +1,95 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "SDL_internal.h"
+
+#include "SDL_poll.h"
+
+#ifdef HAVE_POLL
+#include <poll.h>
+#else
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#endif
+#include <errno.h>
+
+int SDL_IOReady(int fd, int flags, Sint64 timeoutNS)
+{
+    int result;
+
+    SDL_assert(flags & (SDL_IOR_READ | SDL_IOR_WRITE));
+
+    // Note: We don't bother to account for elapsed time if we get EINTR
+    do {
+#ifdef HAVE_POLL
+        struct pollfd info;
+        int timeoutMS;
+
+        info.fd = fd;
+        info.events = 0;
+        if (flags & SDL_IOR_READ) {
+            info.events |= POLLIN | POLLPRI;
+        }
+        if (flags & SDL_IOR_WRITE) {
+            info.events |= POLLOUT;
+        }
+        // FIXME: Add support for ppoll() for nanosecond precision
+        if (timeoutNS > 0) {
+            timeoutMS = (int)SDL_NS_TO_MS(timeoutNS + (SDL_NS_PER_MS - 1));
+        } else if (timeoutNS == 0) {
+            timeoutMS = 0;
+        } else {
+            timeoutMS = -1;
+        }
+        result = poll(&info, 1, timeoutMS);
+#else
+        fd_set rfdset, *rfdp = NULL;
+        fd_set wfdset, *wfdp = NULL;
+        struct timeval tv, *tvp = NULL;
+
+        // If this assert triggers we'll corrupt memory here
+        SDL_assert(fd >= 0 && fd < FD_SETSIZE);
+
+        if (flags & SDL_IOR_READ) {
+            FD_ZERO(&rfdset);
+            FD_SET(fd, &rfdset);
+            rfdp = &rfdset;
+        }
+        if (flags & SDL_IOR_WRITE) {
+            FD_ZERO(&wfdset);
+            FD_SET(fd, &wfdset);
+            wfdp = &wfdset;
+        }
+
+        if (timeoutNS >= 0) {
+            tv.tv_sec = (timeoutNS / SDL_NS_PER_SECOND);
+            tv.tv_usec = SDL_NS_TO_US((timeoutNS % SDL_NS_PER_SECOND) + (SDL_NS_PER_US - 1));
+            tvp = &tv;
+        }
+
+        result = select(fd + 1, rfdp, wfdp, NULL, tvp);
+#endif // HAVE_POLL
+
+    } while (result < 0 && errno == EINTR && !(flags & SDL_IOR_NO_RETRY));
+
+    return result;
+}