+/*
+ * libev select fd activity backend
+ *
+ * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _WIN32
+/* for unix systems */
+# include <sys/select.h>
+# include <inttypes.h>
+#endif
+
+#ifndef EV_SELECT_USE_FD_SET
+# ifdef NFDBITS
+# define EV_SELECT_USE_FD_SET 0
+# else
+# define EV_SELECT_USE_FD_SET 1
+# endif
+#endif
+
+#if EV_SELECT_IS_WINSOCKET
+# undef EV_SELECT_USE_FD_SET
+# define EV_SELECT_USE_FD_SET 1
+# undef EINTR
+# define EINTR WSAEINTR
+# undef EBADF
+# define EBADF WSAENOTSOCK
+# undef ENOMEM
+# define ENOMEM (errno + 1)
+#endif
+
+#if !EV_SELECT_USE_FD_SET
+# define NFDBYTES (NFDBITS / 8)
+#endif
+
+#include <string.h>
+
+static void
+select_modify (EV_P_ int fd, int oev, int nev)
+{
+ if (oev == nev)
+ return;
+
+ {
+#if EV_SELECT_USE_FD_SET
+
+ #if EV_SELECT_IS_WINSOCKET
+ SOCKET handle = anfds [fd].handle;
+ #else
+ int handle = fd;
+ #endif
+
+ if (nev & EV_READ)
+ FD_SET (handle, (fd_set *)vec_ri);
+ else
+ FD_CLR (handle, (fd_set *)vec_ri);
+
+ if (nev & EV_WRITE)
+ FD_SET (handle, (fd_set *)vec_wi);
+ else
+ FD_CLR (handle, (fd_set *)vec_wi);
+
+#else
+
+ int word = fd / NFDBITS;
+ int mask = 1UL << (fd % NFDBITS);
+
+ if (vec_max < word + 1)
+ {
+ int new_max = word + 1;
+
+ vec_ri = ev_realloc (vec_ri, new_max * NFDBYTES);
+ vec_ro = ev_realloc (vec_ro, new_max * NFDBYTES); /* could free/malloc */
+ vec_wi = ev_realloc (vec_wi, new_max * NFDBYTES);
+ vec_wo = ev_realloc (vec_wo, new_max * NFDBYTES); /* could free/malloc */
+
+ for (; vec_max < new_max; ++vec_max)
+ ((fd_mask *)vec_ri)[vec_max] =
+ ((fd_mask *)vec_wi)[vec_max] = 0;
+ }
+
+ ((fd_mask *)vec_ri) [word] |= mask;
+ if (!(nev & EV_READ))
+ ((fd_mask *)vec_ri) [word] &= ~mask;
+
+ ((fd_mask *)vec_wi) [word] |= mask;
+ if (!(nev & EV_WRITE))
+ ((fd_mask *)vec_wi) [word] &= ~mask;
+#endif
+ }
+}
+
+static void
+select_poll (EV_P_ ev_tstamp timeout)
+{
+ struct timeval tv;
+ int res;
+
+#if EV_SELECT_USE_FD_SET
+ memcpy (vec_ro, vec_ri, sizeof (fd_set));
+ memcpy (vec_wo, vec_wi, sizeof (fd_set));
+#else
+ memcpy (vec_ro, vec_ri, vec_max * NFDBYTES);
+ memcpy (vec_wo, vec_wi, vec_max * NFDBYTES);
+#endif
+
+ tv.tv_sec = (long)timeout;
+ tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
+
+ res = select (vec_max * NFDBITS, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
+
+ if (res < 0)
+ {
+ #if EV_SELECT_IS_WINSOCKET
+ errno = WSAGetLastError ();
+ #endif
+
+ if (errno == EBADF)
+ fd_ebadf (EV_A);
+ else if (errno == ENOMEM && !syserr_cb)
+ fd_enomem (EV_A);
+ else if (errno != EINTR)
+ syserr ("(libev) select");
+
+ return;
+ }
+
+#if EV_SELECT_USE_FD_SET
+
+ {
+ int fd;
+
+ for (fd = 0; fd < anfdmax; ++fd)
+ if (anfds [fd].events)
+ {
+ int events = 0;
+ #if EV_SELECT_IS_WINSOCKET
+ SOCKET handle = anfds [fd].handle;
+ #else
+ int handle = fd;
+ #endif
+
+ if (FD_ISSET (handle, (fd_set *)vec_ro)) events |= EV_READ;
+ if (FD_ISSET (handle, (fd_set *)vec_wo)) events |= EV_WRITE;
+
+ if (events)
+ fd_event (EV_A_ fd, events);
+ }
+ }
+
+#else
+
+ {
+ int word, bit;
+ for (word = vec_max; word--; )
+ {
+ fd_mask word_r = ((fd_mask *)vec_ro) [word];
+ fd_mask word_w = ((fd_mask *)vec_wo) [word];
+
+ if (word_r || word_w)
+ for (bit = NFDBITS; bit--; )
+ {
+ fd_mask mask = 1UL << bit;
+ int events = 0;
+
+ events |= word_r & mask ? EV_READ : 0;
+ events |= word_w & mask ? EV_WRITE : 0;
+
+ if (events)
+ fd_event (EV_A_ word * NFDBITS + bit, events);
+ }
+ }
+ }
+
+#endif
+}
+
+static int
+select_init (EV_P_ int flags)
+{
+ method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */
+ method_modify = select_modify;
+ method_poll = select_poll;
+
+#if EV_SELECT_USE_FD_SET
+ vec_max = FD_SETSIZE / 32;
+ vec_ri = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_ri);
+ vec_ro = ev_malloc (sizeof (fd_set));
+ vec_wi = ev_malloc (sizeof (fd_set)); FD_ZERO ((fd_set *)vec_wi);
+ vec_wo = ev_malloc (sizeof (fd_set));
+#else
+ vec_max = 0;
+ vec_ri = 0;
+ vec_ri = 0;
+ vec_wo = 0;
+ vec_wo = 0;
+#endif
+
+ return EVBACKEND_SELECT;
+}
+
+static void
+select_destroy (EV_P)
+{
+ ev_free (vec_ri);
+ ev_free (vec_ro);
+ ev_free (vec_wi);
+ ev_free (vec_wo);
+}
+
+
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