historical/toontown-classic.git/panda/include/atomicAdjustPosixImpl.I

147 lines
4.3 KiB
Text
Raw Normal View History

2024-01-16 11:20:27 -06:00
/**
* PANDA 3D SOFTWARE
* Copyright (c) Carnegie Mellon University. All rights reserved.
*
* All use of this software is subject to the terms of the revised BSD
* license. You should have received a copy of this license along
* with this source code in a file named "LICENSE."
*
* @file atomicAdjustPosixImpl.I
* @author drose
* @date 2006-02-10
*/
/**
* Atomically increments the indicated variable.
*/
INLINE void AtomicAdjustPosixImpl::
inc(TVOLATILE AtomicAdjustPosixImpl::Integer &var) {
pthread_mutex_lock(&_mutex);
++var;
pthread_mutex_unlock(&_mutex);
}
/**
* Atomically decrements the indicated variable and returns true if the new
* value is nonzero, false if it is zero.
*/
INLINE bool AtomicAdjustPosixImpl::
dec(TVOLATILE AtomicAdjustPosixImpl::Integer &var) {
pthread_mutex_lock(&_mutex);
Integer result = --var;
pthread_mutex_unlock(&_mutex);
return (result != 0);
}
/**
* Atomically computes var += delta. It is legal for delta to be negative.
* Returns the result of the addition.
*/
INLINE AtomicAdjustPosixImpl::Integer AtomicAdjustPosixImpl::
add(TVOLATILE AtomicAdjustPosixImpl::Integer &var,
AtomicAdjustPosixImpl::Integer delta) {
pthread_mutex_lock(&_mutex);
Integer new_value = var + delta;
var = new_value;
pthread_mutex_unlock(&_mutex);
return new_value;
}
/**
* Atomically changes the indicated variable and returns the original value.
*/
INLINE AtomicAdjustPosixImpl::Integer AtomicAdjustPosixImpl::
set(TVOLATILE AtomicAdjustPosixImpl::Integer &var,
AtomicAdjustPosixImpl::Integer new_value) {
pthread_mutex_lock(&_mutex);
Integer orig_value = var;
var = new_value;
pthread_mutex_unlock(&_mutex);
return orig_value;
}
/**
* Atomically retrieves the snapshot value of the indicated variable. This is
* the only guaranteed safe way to retrieve the value that other threads might
* be asynchronously setting, incrementing, or decrementing (via other
* AtomicAjust methods).
*/
INLINE AtomicAdjustPosixImpl::Integer AtomicAdjustPosixImpl::
get(const TVOLATILE AtomicAdjustPosixImpl::Integer &var) {
pthread_mutex_lock(&_mutex);
Integer orig_value = var;
pthread_mutex_unlock(&_mutex);
return orig_value;
}
/**
* Atomically changes the indicated variable and returns the original value.
*/
INLINE AtomicAdjustPosixImpl::Pointer AtomicAdjustPosixImpl::
set_ptr(TVOLATILE AtomicAdjustPosixImpl::Pointer &var,
AtomicAdjustPosixImpl::Pointer new_value) {
pthread_mutex_lock(&_mutex);
Pointer orig_value = var;
var = new_value;
pthread_mutex_unlock(&_mutex);
return orig_value;
}
/**
* Atomically retrieves the snapshot value of the indicated variable. This is
* the only guaranteed safe way to retrieve the value that other threads might
* be asynchronously setting, incrementing, or decrementing (via other
* AtomicAjust methods).
*/
INLINE AtomicAdjustPosixImpl::Pointer AtomicAdjustPosixImpl::
get_ptr(const TVOLATILE AtomicAdjustPosixImpl::Pointer &var) {
pthread_mutex_lock(&_mutex);
Pointer orig_value = var;
pthread_mutex_unlock(&_mutex);
return orig_value;
}
/**
* Atomic compare and exchange.
*
* If mem is equal to old_value, store new_value in mem. In either case,
* return the original value of mem. The caller can test for success by
* comparing return_value == old_value.
*
* The atomic function expressed in pseudo-code:
*
* orig_value = mem; if (mem == old_value) { mem = new_value; } return
* orig_value;
*
*/
INLINE AtomicAdjustPosixImpl::Integer AtomicAdjustPosixImpl::
compare_and_exchange(TVOLATILE AtomicAdjustPosixImpl::Integer &mem,
AtomicAdjustPosixImpl::Integer old_value,
AtomicAdjustPosixImpl::Integer new_value) {
pthread_mutex_lock(&_mutex);
Integer orig_value = mem;
if (mem == old_value) {
mem = new_value;
}
pthread_mutex_unlock(&_mutex);
return orig_value;
}
/**
* Atomic compare and exchange.
*
* As above, but works on pointers instead of integers.
*/
INLINE AtomicAdjustPosixImpl::Pointer AtomicAdjustPosixImpl::
compare_and_exchange_ptr(TVOLATILE AtomicAdjustPosixImpl::Pointer &mem,
AtomicAdjustPosixImpl::Pointer old_value,
AtomicAdjustPosixImpl::Pointer new_value) {
pthread_mutex_lock(&_mutex);
Pointer orig_value = mem;
if (mem == old_value) {
mem = new_value;
}
pthread_mutex_unlock(&_mutex);
return orig_value;
}