mirror of
https://github.com/hermitcore/libhermit.git
synced 2025-03-09 00:00:03 +01:00
122 lines
3.5 KiB
C
122 lines
3.5 KiB
C
/*
|
|
* Copyright (c) 2016, Daniel Krebs, RWTH Aachen University
|
|
* 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.
|
|
* * Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this
|
|
* software without specific prior written permission.
|
|
*
|
|
* 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 REGENTS 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.
|
|
*/
|
|
|
|
/**
|
|
* @author Daniel Krebs
|
|
* @file include/hermit/dequeue.h
|
|
* @brief Double-ended queue implementation
|
|
*/
|
|
|
|
#include <hermit/stddef.h>
|
|
#include <hermit/spinlock.h>
|
|
#include <hermit/errno.h>
|
|
#include <string.h>
|
|
|
|
#ifndef __DEQUEUE_H__
|
|
#define __DEQUEUE_H__
|
|
|
|
#define NOT_NULL(dequeue) do { \
|
|
if(BUILTIN_EXPECT(!dequeue, 0)) { \
|
|
return -EINVAL; \
|
|
} \
|
|
} while(0)
|
|
|
|
typedef struct _dequeue_t {
|
|
size_t front; ///< point to first used entry
|
|
size_t back; ///< point to first unused entry
|
|
spinlock_t lock; ///< make dequeue thread safe
|
|
char* buffer; ///< pointer to buffer that holds elements
|
|
size_t buffer_length; ///< number of elements buffer can hold
|
|
size_t element_size; ///< size of one element in buffer
|
|
} dequeue_t;
|
|
|
|
static inline int
|
|
dequeue_init(dequeue_t* dequeue, void* buffer, size_t buffer_length, size_t element_size)
|
|
{
|
|
NOT_NULL(dequeue);
|
|
|
|
dequeue->front = 0;
|
|
dequeue->back = 0;
|
|
|
|
dequeue->buffer = buffer;
|
|
dequeue->buffer_length = buffer_length;
|
|
dequeue->element_size = element_size;
|
|
|
|
spinlock_init(&dequeue->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline int
|
|
dequeue_push(dequeue_t* dequeue, void* v)
|
|
{
|
|
NOT_NULL(dequeue);
|
|
|
|
spinlock_lock(&dequeue->lock);
|
|
|
|
size_t new_back = (dequeue->back + 1) % dequeue->buffer_length;
|
|
if(new_back == dequeue->front) {
|
|
spinlock_unlock(&dequeue->lock);
|
|
return -EOVERFLOW;
|
|
}
|
|
|
|
memcpy(&dequeue->buffer[dequeue->back * dequeue->element_size],
|
|
v,
|
|
dequeue->element_size);
|
|
|
|
dequeue->back = new_back;
|
|
|
|
spinlock_unlock(&dequeue->lock);
|
|
return 0;
|
|
}
|
|
|
|
static inline int
|
|
dequeue_pop(dequeue_t* dequeue, void* out)
|
|
{
|
|
|
|
NOT_NULL(dequeue);
|
|
NOT_NULL(out);
|
|
|
|
spinlock_lock(&dequeue->lock);
|
|
|
|
if(dequeue->front == dequeue->back) {
|
|
spinlock_unlock(&dequeue->lock);
|
|
return -ENOENT;
|
|
}
|
|
|
|
memcpy(out,
|
|
&dequeue->buffer[dequeue->front * dequeue->element_size],
|
|
dequeue->element_size);
|
|
|
|
dequeue->front = (dequeue->front + 1) % dequeue->buffer_length;
|
|
|
|
spinlock_unlock(&dequeue->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif // __DEQUEUE_H__
|