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/*
* Copyright 2002-2019 Intel Corporation.
*
* This software and the related documents are Intel copyrighted materials, and your
* use of them is governed by the express license under which they were provided to
* you ("License"). Unless the License provides otherwise, you may not use, modify,
* copy, publish, distribute, disclose or transmit this software or the related
* documents without Intel's prior written permission.
*
* This software and the related documents are provided as is, with no express or
* implied warranties, other than those that are expressly stated in the License.
*/
// <COMPONENT>: os-apis
// <FILE-TYPE>: component public header
#ifndef OS_APIS_RW_LOCK_H__
#define OS_APIS_RW_LOCK_H__
#include "os-apis.h"
/*!
* @defgroup OS_APIS_RW_LOCK Readers writers lock
* @brief Implementation of readers writers lock.
*/
typedef enum
{
OS_APIS_RW_LOCK_OWNER_TYPE_NONE,
OS_APIS_RW_LOCK_OWNER_TYPE_WRITER,
OS_APIS_RW_LOCK_OWNER_TYPE_READER
} OS_APIS_RW_LOCK_OWNER_TYPE;
/*!
* This is an opaque struct for readers/writers lock.
* This struct should be used with the functions declared in this header.
*/
typedef struct
{
OS_MUTEX_TYPE_IMPL lock;
OS_APIS_RW_LOCK_OWNER_TYPE owner_type;
UINT32 readers;
OS_EVENT no_readers_event;
UINT32 waiters_count;
#ifndef TARGET_WINDOWS
UINT32 spinlock_fork_count;
#endif
} OS_APIS_RW_LOCK_IMPL_T;
typedef PRE_ALIGNTO(CPU_MEMORY_CACHELINE_SIZE) union
{
OS_APIS_RW_LOCK_IMPL_T impl;
char reserved[2 * CPU_MEMORY_CACHELINE_SIZE];
} POST_ALIGNTO(CPU_MEMORY_CACHELINE_SIZE) OS_APIS_RW_LOCK_T;
/*!
* Static initializer for OS_APIS_RW_LOCK_T type.
*/
#ifdef TARGET_WINDOWS
# define OS_APIS_RW_LOCK_INITIALIZER {{OS_APIS_MUTEX_IMPL_DEPTH_SIMPLE_INITIALIZER, OS_APIS_RW_LOCK_OWNER_TYPE_NONE, \
(UINT32)0, OS_EVENT_INITIALIZER, (UINT32)0}}
#else
# define OS_APIS_RW_LOCK_INITIALIZER {{OS_APIS_MUTEX_IMPL_DEPTH_SIMPLE_INITIALIZER, OS_APIS_RW_LOCK_OWNER_TYPE_NONE, \
(UINT32)0, OS_EVENT_INITIALIZER, (UINT32)0, (UINT32)0}}
#endif
/*! @ingroup OS_APIS_RW_LOCK
* Initializes a reader-writer lock.
*
* @param[in] lock The lock to initialize
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
void OS_RWLockInitialize(volatile OS_APIS_RW_LOCK_T* l);
/*! @ingroup OS_APIS_RW_LOCK
* Destroy a reader-writer lock, freeing all exhausted resources associated with the lock.
*
* @param[in] lock The lock to destroy
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
void OS_RWLockDestroy(volatile OS_APIS_RW_LOCK_T* l);
/*! @ingroup OS_APIS_RW_LOCK
* Acquires the lock for writer.
* Blocks until the writer lock is acquired.
*
* @param[in] lock The lock to acquire
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
void OS_RWLockAcquireWrite(volatile OS_APIS_RW_LOCK_T* lock);
/*! @ingroup OS_APIS_RW_LOCK
* Releases the lock for writer.
*
* @param[in] lock The lock to release
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
void OS_RWLockReleaseWrite(volatile OS_APIS_RW_LOCK_T* lock);
/*! @ingroup OS_APIS_RW_LOCK
* Acquires the lock for reader.
* Blocks until the reader lock is acquired.
*
* @param[in] lock The lock to acquire
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
void OS_RWLockAcquireRead(volatile OS_APIS_RW_LOCK_T* lock);
/*! @ingroup OS_APIS_RW_LOCK
* Releases the lock for reader.
*
* @param[in] lock The lock to release
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
void OS_RWLockReleaseRead(volatile OS_APIS_RW_LOCK_T* lock);
/*! @ingroup OS_APIS_RW_LOCK
* Releases the lock that was acquired.
* The lock kind that was acquired (whether its read or write) is determined by this function.
*
* @param[in] lock The lock to release
*
* @return TRUE if the lock was taken (for either read or write) and as a result of this call is unlocked, FALSE otherwise.
* If the reader lock was released, and a waiting writer was woken up and acquired the lock, the function will
* return TRUE.
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
BOOL_T OS_RWLockRelease(volatile OS_APIS_RW_LOCK_T* l);
/*! @ingroup OS_APIS_RW_LOCK
* Tries to Acquire the lock for writer.
* This function returns immediately if the lock can't be acquired.
*
* @param[in] lock The lock to acquire
*
* @return TRUE If the writer lock was acquired.
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
BOOL_T OS_RWLockTryAcquireWrite(volatile OS_APIS_RW_LOCK_T* l);
/*! @ingroup OS_APIS_RW_LOCK
* Tries to Acquire the lock for reader.
* This function returns immediately if the lock can't be acquired.
*
* @param[in] lock The lock to acquire
*
* @return TRUE If the reader lock was acquired.
*
* @par Availability:
* @b O/S: Windows, Linux & macOS*\n
* @b CPU: All\n
*/
BOOL_T OS_RWLockTryAcquireRead(volatile OS_APIS_RW_LOCK_T* l);
#endif // OS_APIS_RW_LOCK_H__