add gnulib files
diff --git a/gnulib/lib/windows-initguard.h b/gnulib/lib/windows-initguard.h
new file mode 100644
index 0000000..8aefd0b
--- /dev/null
+++ b/gnulib/lib/windows-initguard.h
@@ -0,0 +1,35 @@
+/* Init guards, somewhat like spinlocks (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#ifndef _WINDOWS_INITGUARD_H
+#define _WINDOWS_INITGUARD_H
+
+#define WIN32_LEAN_AND_MEAN /* avoid including junk */
+#include <windows.h>
+
+typedef struct
+ {
+ volatile int done;
+ volatile LONG started;
+ }
+ glwthread_initguard_t;
+
+#define GLWTHREAD_INITGUARD_INIT { 0, -1 }
+
+#endif /* _WINDOWS_INITGUARD_H */
diff --git a/gnulib/lib/windows-mutex.c b/gnulib/lib/windows-mutex.c
new file mode 100644
index 0000000..9433881
--- /dev/null
+++ b/gnulib/lib/windows-mutex.c
@@ -0,0 +1,95 @@
+/* Plain mutexes (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#include <config.h>
+
+/* Specification. */
+#include "windows-mutex.h"
+
+#include <errno.h>
+
+void
+glwthread_mutex_init (glwthread_mutex_t *mutex)
+{
+ InitializeCriticalSection (&mutex->lock);
+ mutex->guard.done = 1;
+}
+
+int
+glwthread_mutex_lock (glwthread_mutex_t *mutex)
+{
+ if (!mutex->guard.done)
+ {
+ if (InterlockedIncrement (&mutex->guard.started) == 0)
+ /* This thread is the first one to need this mutex. Initialize it. */
+ glwthread_mutex_init (mutex);
+ else
+ {
+ /* Don't let mutex->guard.started grow and wrap around. */
+ InterlockedDecrement (&mutex->guard.started);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this mutex. */
+ while (!mutex->guard.done)
+ Sleep (0);
+ }
+ }
+ EnterCriticalSection (&mutex->lock);
+ return 0;
+}
+
+int
+glwthread_mutex_trylock (glwthread_mutex_t *mutex)
+{
+ if (!mutex->guard.done)
+ {
+ if (InterlockedIncrement (&mutex->guard.started) == 0)
+ /* This thread is the first one to need this mutex. Initialize it. */
+ glwthread_mutex_init (mutex);
+ else
+ {
+ /* Don't let mutex->guard.started grow and wrap around. */
+ InterlockedDecrement (&mutex->guard.started);
+ /* Let another thread finish initializing this mutex, and let it also
+ lock this mutex. */
+ return EBUSY;
+ }
+ }
+ if (!TryEnterCriticalSection (&mutex->lock))
+ return EBUSY;
+ return 0;
+}
+
+int
+glwthread_mutex_unlock (glwthread_mutex_t *mutex)
+{
+ if (!mutex->guard.done)
+ return EINVAL;
+ LeaveCriticalSection (&mutex->lock);
+ return 0;
+}
+
+int
+glwthread_mutex_destroy (glwthread_mutex_t *mutex)
+{
+ if (!mutex->guard.done)
+ return EINVAL;
+ DeleteCriticalSection (&mutex->lock);
+ mutex->guard.done = 0;
+ return 0;
+}
diff --git a/gnulib/lib/windows-mutex.h b/gnulib/lib/windows-mutex.h
new file mode 100644
index 0000000..5364f92
--- /dev/null
+++ b/gnulib/lib/windows-mutex.h
@@ -0,0 +1,51 @@
+/* Plain mutexes (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#ifndef _WINDOWS_MUTEX_H
+#define _WINDOWS_MUTEX_H
+
+#define WIN32_LEAN_AND_MEAN /* avoid including junk */
+#include <windows.h>
+
+#include "windows-initguard.h"
+
+typedef struct
+ {
+ glwthread_initguard_t guard; /* protects the initialization */
+ CRITICAL_SECTION lock;
+ }
+ glwthread_mutex_t;
+
+#define GLWTHREAD_MUTEX_INIT { GLWTHREAD_INITGUARD_INIT }
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern void glwthread_mutex_init (glwthread_mutex_t *mutex);
+extern int glwthread_mutex_lock (glwthread_mutex_t *mutex);
+extern int glwthread_mutex_trylock (glwthread_mutex_t *mutex);
+extern int glwthread_mutex_unlock (glwthread_mutex_t *mutex);
+extern int glwthread_mutex_destroy (glwthread_mutex_t *mutex);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _WINDOWS_MUTEX_H */
diff --git a/gnulib/lib/windows-once.c b/gnulib/lib/windows-once.c
new file mode 100644
index 0000000..455c50e
--- /dev/null
+++ b/gnulib/lib/windows-once.c
@@ -0,0 +1,62 @@
+/* Once-only control (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#include <config.h>
+
+/* Specification. */
+#include "windows-once.h"
+
+#include <stdlib.h>
+
+void
+glwthread_once (glwthread_once_t *once_control, void (*initfunction) (void))
+{
+ if (once_control->inited <= 0)
+ {
+ if (InterlockedIncrement (&once_control->started) == 0)
+ {
+ /* This thread is the first one to come to this once_control. */
+ InitializeCriticalSection (&once_control->lock);
+ EnterCriticalSection (&once_control->lock);
+ once_control->inited = 0;
+ initfunction ();
+ once_control->inited = 1;
+ LeaveCriticalSection (&once_control->lock);
+ }
+ else
+ {
+ /* Don't let once_control->started grow and wrap around. */
+ InterlockedDecrement (&once_control->started);
+ /* Some other thread has already started the initialization.
+ Yield the CPU while waiting for the other thread to finish
+ initializing and taking the lock. */
+ while (once_control->inited < 0)
+ Sleep (0);
+ if (once_control->inited <= 0)
+ {
+ /* Take the lock. This blocks until the other thread has
+ finished calling the initfunction. */
+ EnterCriticalSection (&once_control->lock);
+ LeaveCriticalSection (&once_control->lock);
+ if (!(once_control->inited > 0))
+ abort ();
+ }
+ }
+ }
+}
diff --git a/gnulib/lib/windows-once.h b/gnulib/lib/windows-once.h
new file mode 100644
index 0000000..1599983
--- /dev/null
+++ b/gnulib/lib/windows-once.h
@@ -0,0 +1,47 @@
+/* Once-only control (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#ifndef _WINDOWS_ONCE_H
+#define _WINDOWS_ONCE_H
+
+#define WIN32_LEAN_AND_MEAN /* avoid including junk */
+#include <windows.h>
+
+typedef struct
+ {
+ volatile int inited;
+ volatile LONG started;
+ CRITICAL_SECTION lock;
+ }
+ glwthread_once_t;
+
+#define GLWTHREAD_ONCE_INIT { -1, -1 }
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern void glwthread_once (glwthread_once_t *once_control,
+ void (*initfunction) (void));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _WINDOWS_ONCE_H */
diff --git a/gnulib/lib/windows-recmutex.c b/gnulib/lib/windows-recmutex.c
new file mode 100644
index 0000000..7e6e446
--- /dev/null
+++ b/gnulib/lib/windows-recmutex.c
@@ -0,0 +1,127 @@
+/* Plain recursive mutexes (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#include <config.h>
+
+/* Specification. */
+#include "windows-recmutex.h"
+
+#include <errno.h>
+
+void
+glwthread_recmutex_init (glwthread_recmutex_t *mutex)
+{
+ mutex->owner = 0;
+ mutex->depth = 0;
+ InitializeCriticalSection (&mutex->lock);
+ mutex->guard.done = 1;
+}
+
+int
+glwthread_recmutex_lock (glwthread_recmutex_t *mutex)
+{
+ if (!mutex->guard.done)
+ {
+ if (InterlockedIncrement (&mutex->guard.started) == 0)
+ /* This thread is the first one to need this mutex. Initialize it. */
+ glwthread_recmutex_init (mutex);
+ else
+ {
+ /* Don't let mutex->guard.started grow and wrap around. */
+ InterlockedDecrement (&mutex->guard.started);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this mutex. */
+ while (!mutex->guard.done)
+ Sleep (0);
+ }
+ }
+ {
+ DWORD self = GetCurrentThreadId ();
+ if (mutex->owner != self)
+ {
+ EnterCriticalSection (&mutex->lock);
+ mutex->owner = self;
+ }
+ if (++(mutex->depth) == 0) /* wraparound? */
+ {
+ mutex->depth--;
+ return EAGAIN;
+ }
+ }
+ return 0;
+}
+
+int
+glwthread_recmutex_trylock (glwthread_recmutex_t *mutex)
+{
+ if (!mutex->guard.done)
+ {
+ if (InterlockedIncrement (&mutex->guard.started) == 0)
+ /* This thread is the first one to need this mutex. Initialize it. */
+ glwthread_recmutex_init (mutex);
+ else
+ {
+ /* Don't let mutex->guard.started grow and wrap around. */
+ InterlockedDecrement (&mutex->guard.started);
+ /* Let another thread finish initializing this mutex, and let it also
+ lock this mutex. */
+ return EBUSY;
+ }
+ }
+ {
+ DWORD self = GetCurrentThreadId ();
+ if (mutex->owner != self)
+ {
+ if (!TryEnterCriticalSection (&mutex->lock))
+ return EBUSY;
+ mutex->owner = self;
+ }
+ if (++(mutex->depth) == 0) /* wraparound? */
+ {
+ mutex->depth--;
+ return EAGAIN;
+ }
+ }
+ return 0;
+}
+
+int
+glwthread_recmutex_unlock (glwthread_recmutex_t *mutex)
+{
+ if (mutex->owner != GetCurrentThreadId ())
+ return EPERM;
+ if (mutex->depth == 0)
+ return EINVAL;
+ if (--(mutex->depth) == 0)
+ {
+ mutex->owner = 0;
+ LeaveCriticalSection (&mutex->lock);
+ }
+ return 0;
+}
+
+int
+glwthread_recmutex_destroy (glwthread_recmutex_t *mutex)
+{
+ if (mutex->owner != 0)
+ return EBUSY;
+ DeleteCriticalSection (&mutex->lock);
+ mutex->guard.done = 0;
+ return 0;
+}
diff --git a/gnulib/lib/windows-recmutex.h b/gnulib/lib/windows-recmutex.h
new file mode 100644
index 0000000..d143108
--- /dev/null
+++ b/gnulib/lib/windows-recmutex.h
@@ -0,0 +1,57 @@
+/* Plain recursive mutexes (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#ifndef _WINDOWS_RECMUTEX_H
+#define _WINDOWS_RECMUTEX_H
+
+#define WIN32_LEAN_AND_MEAN /* avoid including junk */
+#include <windows.h>
+
+#include "windows-initguard.h"
+
+/* The native Windows documentation says that CRITICAL_SECTION already
+ implements a recursive lock. But we need not rely on it: It's easy to
+ implement a recursive lock without this assumption. */
+
+typedef struct
+ {
+ glwthread_initguard_t guard; /* protects the initialization */
+ DWORD owner;
+ unsigned long depth;
+ CRITICAL_SECTION lock;
+ }
+ glwthread_recmutex_t;
+
+#define GLWTHREAD_RECMUTEX_INIT { GLWTHREAD_INITGUARD_INIT, 0, 0 }
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern void glwthread_recmutex_init (glwthread_recmutex_t *mutex);
+extern int glwthread_recmutex_lock (glwthread_recmutex_t *mutex);
+extern int glwthread_recmutex_trylock (glwthread_recmutex_t *mutex);
+extern int glwthread_recmutex_unlock (glwthread_recmutex_t *mutex);
+extern int glwthread_recmutex_destroy (glwthread_recmutex_t *mutex);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _WINDOWS_RECMUTEX_H */
diff --git a/gnulib/lib/windows-rwlock.c b/gnulib/lib/windows-rwlock.c
new file mode 100644
index 0000000..9207d1b
--- /dev/null
+++ b/gnulib/lib/windows-rwlock.c
@@ -0,0 +1,373 @@
+/* Read-write locks (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#include <config.h>
+
+/* Specification. */
+#include "windows-rwlock.h"
+
+#include <errno.h>
+#include <stdlib.h>
+
+/* In this file, the waitqueues are implemented as circular arrays. */
+#define glwthread_waitqueue_t glwthread_carray_waitqueue_t
+
+static void
+glwthread_waitqueue_init (glwthread_waitqueue_t *wq)
+{
+ wq->array = NULL;
+ wq->count = 0;
+ wq->alloc = 0;
+ wq->offset = 0;
+}
+
+/* Enqueues the current thread, represented by an event, in a wait queue.
+ Returns INVALID_HANDLE_VALUE if an allocation failure occurs. */
+static HANDLE
+glwthread_waitqueue_add (glwthread_waitqueue_t *wq)
+{
+ HANDLE event;
+ unsigned int index;
+
+ if (wq->count == wq->alloc)
+ {
+ unsigned int new_alloc = 2 * wq->alloc + 1;
+ HANDLE *new_array =
+ (HANDLE *) realloc (wq->array, new_alloc * sizeof (HANDLE));
+ if (new_array == NULL)
+ /* No more memory. */
+ return INVALID_HANDLE_VALUE;
+ /* Now is a good opportunity to rotate the array so that its contents
+ starts at offset 0. */
+ if (wq->offset > 0)
+ {
+ unsigned int old_count = wq->count;
+ unsigned int old_alloc = wq->alloc;
+ unsigned int old_offset = wq->offset;
+ unsigned int i;
+ if (old_offset + old_count > old_alloc)
+ {
+ unsigned int limit = old_offset + old_count - old_alloc;
+ for (i = 0; i < limit; i++)
+ new_array[old_alloc + i] = new_array[i];
+ }
+ for (i = 0; i < old_count; i++)
+ new_array[i] = new_array[old_offset + i];
+ wq->offset = 0;
+ }
+ wq->array = new_array;
+ wq->alloc = new_alloc;
+ }
+ /* Whether the created event is a manual-reset one or an auto-reset one,
+ does not matter, since we will wait on it only once. */
+ event = CreateEvent (NULL, TRUE, FALSE, NULL);
+ if (event == INVALID_HANDLE_VALUE)
+ /* No way to allocate an event. */
+ return INVALID_HANDLE_VALUE;
+ index = wq->offset + wq->count;
+ if (index >= wq->alloc)
+ index -= wq->alloc;
+ wq->array[index] = event;
+ wq->count++;
+ return event;
+}
+
+/* Notifies the first thread from a wait queue and dequeues it. */
+static void
+glwthread_waitqueue_notify_first (glwthread_waitqueue_t *wq)
+{
+ SetEvent (wq->array[wq->offset + 0]);
+ wq->offset++;
+ wq->count--;
+ if (wq->count == 0 || wq->offset == wq->alloc)
+ wq->offset = 0;
+}
+
+/* Notifies all threads from a wait queue and dequeues them all. */
+static void
+glwthread_waitqueue_notify_all (glwthread_waitqueue_t *wq)
+{
+ unsigned int i;
+
+ for (i = 0; i < wq->count; i++)
+ {
+ unsigned int index = wq->offset + i;
+ if (index >= wq->alloc)
+ index -= wq->alloc;
+ SetEvent (wq->array[index]);
+ }
+ wq->count = 0;
+ wq->offset = 0;
+}
+
+void
+glwthread_rwlock_init (glwthread_rwlock_t *lock)
+{
+ InitializeCriticalSection (&lock->lock);
+ glwthread_waitqueue_init (&lock->waiting_readers);
+ glwthread_waitqueue_init (&lock->waiting_writers);
+ lock->runcount = 0;
+ lock->guard.done = 1;
+}
+
+int
+glwthread_rwlock_rdlock (glwthread_rwlock_t *lock)
+{
+ if (!lock->guard.done)
+ {
+ if (InterlockedIncrement (&lock->guard.started) == 0)
+ /* This thread is the first one to need this lock. Initialize it. */
+ glwthread_rwlock_init (lock);
+ else
+ {
+ /* Don't let lock->guard.started grow and wrap around. */
+ InterlockedDecrement (&lock->guard.started);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
+ }
+ }
+ EnterCriticalSection (&lock->lock);
+ /* Test whether only readers are currently running, and whether the runcount
+ field will not overflow, and whether no writer is waiting. The latter
+ condition is because POSIX recommends that "write locks shall take
+ precedence over read locks", to avoid "writer starvation". */
+ if (!(lock->runcount + 1 > 0 && lock->waiting_writers.count == 0))
+ {
+ /* This thread has to wait for a while. Enqueue it among the
+ waiting_readers. */
+ HANDLE event = glwthread_waitqueue_add (&lock->waiting_readers);
+ if (event != INVALID_HANDLE_VALUE)
+ {
+ DWORD result;
+ LeaveCriticalSection (&lock->lock);
+ /* Wait until another thread signals this event. */
+ result = WaitForSingleObject (event, INFINITE);
+ if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
+ abort ();
+ CloseHandle (event);
+ /* The thread which signalled the event already did the bookkeeping:
+ removed us from the waiting_readers, incremented lock->runcount. */
+ if (!(lock->runcount > 0))
+ abort ();
+ return 0;
+ }
+ else
+ {
+ /* Allocation failure. Weird. */
+ do
+ {
+ LeaveCriticalSection (&lock->lock);
+ Sleep (1);
+ EnterCriticalSection (&lock->lock);
+ }
+ while (!(lock->runcount + 1 > 0));
+ }
+ }
+ lock->runcount++;
+ LeaveCriticalSection (&lock->lock);
+ return 0;
+}
+
+int
+glwthread_rwlock_wrlock (glwthread_rwlock_t *lock)
+{
+ if (!lock->guard.done)
+ {
+ if (InterlockedIncrement (&lock->guard.started) == 0)
+ /* This thread is the first one to need this lock. Initialize it. */
+ glwthread_rwlock_init (lock);
+ else
+ {
+ /* Don't let lock->guard.started grow and wrap around. */
+ InterlockedDecrement (&lock->guard.started);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
+ }
+ }
+ EnterCriticalSection (&lock->lock);
+ /* Test whether no readers or writers are currently running. */
+ if (!(lock->runcount == 0))
+ {
+ /* This thread has to wait for a while. Enqueue it among the
+ waiting_writers. */
+ HANDLE event = glwthread_waitqueue_add (&lock->waiting_writers);
+ if (event != INVALID_HANDLE_VALUE)
+ {
+ DWORD result;
+ LeaveCriticalSection (&lock->lock);
+ /* Wait until another thread signals this event. */
+ result = WaitForSingleObject (event, INFINITE);
+ if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
+ abort ();
+ CloseHandle (event);
+ /* The thread which signalled the event already did the bookkeeping:
+ removed us from the waiting_writers, set lock->runcount = -1. */
+ if (!(lock->runcount == -1))
+ abort ();
+ return 0;
+ }
+ else
+ {
+ /* Allocation failure. Weird. */
+ do
+ {
+ LeaveCriticalSection (&lock->lock);
+ Sleep (1);
+ EnterCriticalSection (&lock->lock);
+ }
+ while (!(lock->runcount == 0));
+ }
+ }
+ lock->runcount--; /* runcount becomes -1 */
+ LeaveCriticalSection (&lock->lock);
+ return 0;
+}
+
+int
+glwthread_rwlock_tryrdlock (glwthread_rwlock_t *lock)
+{
+ if (!lock->guard.done)
+ {
+ if (InterlockedIncrement (&lock->guard.started) == 0)
+ /* This thread is the first one to need this lock. Initialize it. */
+ glwthread_rwlock_init (lock);
+ else
+ {
+ /* Don't let lock->guard.started grow and wrap around. */
+ InterlockedDecrement (&lock->guard.started);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
+ }
+ }
+ /* It's OK to wait for this critical section, because it is never taken for a
+ long time. */
+ EnterCriticalSection (&lock->lock);
+ /* Test whether only readers are currently running, and whether the runcount
+ field will not overflow, and whether no writer is waiting. The latter
+ condition is because POSIX recommends that "write locks shall take
+ precedence over read locks", to avoid "writer starvation". */
+ if (!(lock->runcount + 1 > 0 && lock->waiting_writers.count == 0))
+ {
+ /* This thread would have to wait for a while. Return instead. */
+ LeaveCriticalSection (&lock->lock);
+ return EBUSY;
+ }
+ lock->runcount++;
+ LeaveCriticalSection (&lock->lock);
+ return 0;
+}
+
+int
+glwthread_rwlock_trywrlock (glwthread_rwlock_t *lock)
+{
+ if (!lock->guard.done)
+ {
+ if (InterlockedIncrement (&lock->guard.started) == 0)
+ /* This thread is the first one to need this lock. Initialize it. */
+ glwthread_rwlock_init (lock);
+ else
+ {
+ /* Don't let lock->guard.started grow and wrap around. */
+ InterlockedDecrement (&lock->guard.started);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
+ }
+ }
+ /* It's OK to wait for this critical section, because it is never taken for a
+ long time. */
+ EnterCriticalSection (&lock->lock);
+ /* Test whether no readers or writers are currently running. */
+ if (!(lock->runcount == 0))
+ {
+ /* This thread would have to wait for a while. Return instead. */
+ LeaveCriticalSection (&lock->lock);
+ return EBUSY;
+ }
+ lock->runcount--; /* runcount becomes -1 */
+ LeaveCriticalSection (&lock->lock);
+ return 0;
+}
+
+int
+glwthread_rwlock_unlock (glwthread_rwlock_t *lock)
+{
+ if (!lock->guard.done)
+ return EINVAL;
+ EnterCriticalSection (&lock->lock);
+ if (lock->runcount < 0)
+ {
+ /* Drop a writer lock. */
+ if (!(lock->runcount == -1))
+ abort ();
+ lock->runcount = 0;
+ }
+ else
+ {
+ /* Drop a reader lock. */
+ if (!(lock->runcount > 0))
+ {
+ LeaveCriticalSection (&lock->lock);
+ return EPERM;
+ }
+ lock->runcount--;
+ }
+ if (lock->runcount == 0)
+ {
+ /* POSIX recommends that "write locks shall take precedence over read
+ locks", to avoid "writer starvation". */
+ if (lock->waiting_writers.count > 0)
+ {
+ /* Wake up one of the waiting writers. */
+ lock->runcount--;
+ glwthread_waitqueue_notify_first (&lock->waiting_writers);
+ }
+ else
+ {
+ /* Wake up all waiting readers. */
+ lock->runcount += lock->waiting_readers.count;
+ glwthread_waitqueue_notify_all (&lock->waiting_readers);
+ }
+ }
+ LeaveCriticalSection (&lock->lock);
+ return 0;
+}
+
+int
+glwthread_rwlock_destroy (glwthread_rwlock_t *lock)
+{
+ if (!lock->guard.done)
+ return EINVAL;
+ if (lock->runcount != 0)
+ return EBUSY;
+ DeleteCriticalSection (&lock->lock);
+ if (lock->waiting_readers.array != NULL)
+ free (lock->waiting_readers.array);
+ if (lock->waiting_writers.array != NULL)
+ free (lock->waiting_writers.array);
+ lock->guard.done = 0;
+ return 0;
+}
diff --git a/gnulib/lib/windows-rwlock.h b/gnulib/lib/windows-rwlock.h
new file mode 100644
index 0000000..9002040
--- /dev/null
+++ b/gnulib/lib/windows-rwlock.h
@@ -0,0 +1,68 @@
+/* Read-write locks (native Windows implementation).
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.
+ Based on GCC's gthr-win32.h. */
+
+#ifndef _WINDOWS_RWLOCK_H
+#define _WINDOWS_RWLOCK_H
+
+#define WIN32_LEAN_AND_MEAN /* avoid including junk */
+#include <windows.h>
+
+#include "windows-initguard.h"
+
+/* It is impossible to implement read-write locks using plain locks, without
+ introducing an extra thread dedicated to managing read-write locks.
+ Therefore here we need to use the low-level Event type. */
+
+typedef struct
+ {
+ HANDLE *array; /* array of waiting threads, each represented by an event */
+ unsigned int count; /* number of waiting threads */
+ unsigned int alloc; /* length of allocated array */
+ unsigned int offset; /* index of first waiting thread in array */
+ }
+ glwthread_carray_waitqueue_t;
+typedef struct
+ {
+ glwthread_initguard_t guard; /* protects the initialization */
+ CRITICAL_SECTION lock; /* protects the remaining fields */
+ glwthread_carray_waitqueue_t waiting_readers; /* waiting readers */
+ glwthread_carray_waitqueue_t waiting_writers; /* waiting writers */
+ int runcount; /* number of readers running, or -1 when a writer runs */
+ }
+ glwthread_rwlock_t;
+
+#define GLWTHREAD_RWLOCK_INIT { GLWTHREAD_INITGUARD_INIT }
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern void glwthread_rwlock_init (glwthread_rwlock_t *lock);
+extern int glwthread_rwlock_rdlock (glwthread_rwlock_t *lock);
+extern int glwthread_rwlock_wrlock (glwthread_rwlock_t *lock);
+extern int glwthread_rwlock_tryrdlock (glwthread_rwlock_t *lock);
+extern int glwthread_rwlock_trywrlock (glwthread_rwlock_t *lock);
+extern int glwthread_rwlock_unlock (glwthread_rwlock_t *lock);
+extern int glwthread_rwlock_destroy (glwthread_rwlock_t *lock);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _WINDOWS_RWLOCK_H */
