OVMS3-idf/components/esp32/include/xtensa/xos_cond.h

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2016-08-17 15:08:22 +00:00
/** @file */
// xos_cond.h - XOS condition variables API interface and data structures.
// Copyright (c) 2003-2015 Cadence Design Systems, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// NOTE: Do not include this file directly in your application. Including
// xos.h will automatically include this file.
#ifndef __XOS_COND_H__
#define __XOS_COND_H__
#include "xos_types.h"
#ifdef __cplusplus
extern "C" {
#endif
//-----------------------------------------------------------------------------
//
// Function pointer type for condition callbacks (defined in xos_thread.h)
//
// typedef int32_t (XosCondFunc)(void * arg, int32_t sig_value, XosThread * thread);
//
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
///
/// Condition object.
///
//-----------------------------------------------------------------------------
typedef struct XosCond {
XosThreadQueue queue; ///< Queue of waiters.
#if XOS_COND_DEBUG
uint32_t sig; // Signature indicates valid object.
#endif
} XosCond;
//-----------------------------------------------------------------------------
///
/// Initialize a condition object before first use. The object must be
/// allocated by the caller.
///
/// \param cond Pointer to condition object.
///
/// \return Returns nothing.
///
//-----------------------------------------------------------------------------
void
xos_cond_create(XosCond * cond);
//-----------------------------------------------------------------------------
///
/// Destroy a condition object. Must have been previously created by calling
/// xos_cond_create().
///
/// \param cond Pointer to condition object.
///
/// \return Returns nothing.
///
//-----------------------------------------------------------------------------
void
xos_cond_delete(XosCond * cond);
//-----------------------------------------------------------------------------
///
/// Wait on a condition: block until the condition is satisfied. The condition
/// is satisfied when xos_cond_signal() is called on this condition *and* the
/// condition callback function returns non-zero. If there is no callback
/// function, then the condition is automatically satisfied.
///
/// The condition structure must have been initialized before first use by
/// calling xos_cond_create().
///
/// \param cond Pointer to condition object.
///
/// \param cond_fn Pointer to a function, called by xos_cond_signal(),
/// that should return non-zero if this thread is to
/// be resumed. The function is invoked as:
/// `(*cond_fn)(cond_arg, sig_value)`.
///
/// \param cond_arg Argument passed to cond_fn.
///
/// \return Returns the value passed to xos_cond_signal().
///
//-----------------------------------------------------------------------------
int32_t
xos_cond_wait(XosCond * cond, XosCondFunc * cond_fn, void * cond_arg);
//-----------------------------------------------------------------------------
///
/// Trigger the condition: wake all threads waiting on the condition, if their
/// condition function evaluates to true (non-zero). If there is no condition
/// function for a thread then it is automatically awakened.
///
/// The condition structure must have been initialized before first use by
/// calling xos_cond_create().
///
/// \param cond Pointer to condition object.
///
/// \param sig_value Value passed to all waiters, returned by
/// xos_cond_wait().
///
/// \return Returns the number of waiting threads that were resumed.
///
/// NOTE: Signaling a condition that has no waiters has no effect on it, and
/// the signal is not remembered. Any thread that waits on it later must be
/// woken by another call to xos_cond_signal().
///
//-----------------------------------------------------------------------------
int32_t
xos_cond_signal(XosCond * cond, int32_t sig_value);
#ifdef __cplusplus
}
#endif
#endif // __XOS_COND_H__