140 строки
3.5 KiB
C
140 строки
3.5 KiB
C
/* -*- Mode: C; c-basic-offset:4 ; -*- */
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/*
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* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
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* University Research and Technology
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* Corporation. All rights reserved.
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* Copyright (c) 2004-2008 The University of Tennessee and The University
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* of Tennessee Research Foundation. All rights
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* reserved.
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* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
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* University of Stuttgart. All rights reserved.
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* Copyright (c) 2004-2005 The Regents of the University of California.
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* All rights reserved.
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* Copyright (c) 2010 Cisco Systems, Inc. All rights reserved.
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* $COPYRIGHT$
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*
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* Additional copyrights may follow
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*
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* $HEADER$
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*/
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/** @file
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*
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*/
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#ifndef OPAL_RING_BUFFER_H
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#define OPAL_RING_BUFFER_H
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#include "opal_config.h"
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#include "opal/threads/mutex.h"
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#include "opal/class/opal_object.h"
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#include "opal/util/output.h"
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BEGIN_C_DECLS
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/**
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* dynamic pointer ring
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*/
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struct opal_ring_buffer_t {
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/** base class */
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opal_object_t super;
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/** synchronization object */
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opal_mutex_t lock;
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/* head/tail indices */
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char **head;
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char **tail;
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/** size of list, i.e. number of elements in addr */
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int size;
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/** pointer to ring */
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char **addr;
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};
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/**
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* Convenience typedef
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*/
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typedef struct opal_ring_buffer_t opal_ring_buffer_t;
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/**
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* Class declaration
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*/
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OPAL_DECLSPEC OBJ_CLASS_DECLARATION(opal_ring_buffer_t);
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/**
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* Initialize the ring buffer, defining its size.
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*
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* @param ring Pointer to a ring buffer (IN/OUT)
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* @param size The number of elements in the ring (IN)
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*
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* @return OPAL_SUCCESS if all initializations were succesful. Otherwise,
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* the error indicate what went wrong in the function.
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*/
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OPAL_DECLSPEC int opal_ring_buffer_init(opal_ring_buffer_t* ring, int size);
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/**
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* Push an item onto the ring buffer
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*
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* @param ring Pointer to ring (IN)
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* @param ptr Pointer value (IN)
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*
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* @return OPAL_SUCCESS. Returns error if ring cannot take
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* another entry
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*/
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static inline void* opal_ring_buffer_push(opal_ring_buffer_t *ring, void *ptr)
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{
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char *p=NULL;
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OPAL_THREAD_LOCK(&(ring->lock));
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if (NULL != *ring->head) {
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p = *ring->head;
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if (ring->head == ring->tail) {
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/* push the tail ahead of us */
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if (ring->tail == &ring->addr[ring->size-1]) {
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ring->tail = &ring->addr[0];
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} else {
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ring->tail++;
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}
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}
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}
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*ring->head = ptr;
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if (ring->head == &ring->addr[ring->size-1]) {
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ring->head = &ring->addr[0];
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} else {
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ring->head++;
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}
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OPAL_THREAD_UNLOCK(&(ring->lock));
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return (void*)p;
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}
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/**
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* Pop an item off of the ring. The head of the ring will be
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* returned. If nothing on the ring, NULL is returned.
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*
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* @param ring Pointer to ring (IN)
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*
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* @return Error code. NULL indicates an error.
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*/
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static inline void* opal_ring_buffer_pop(opal_ring_buffer_t *ring)
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{
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char *p;
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OPAL_THREAD_LOCK(&(ring->lock));
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if (NULL == ring->tail || ring->head == ring->tail) {
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p = NULL;
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} else {
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p = *ring->tail;
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*ring->tail = NULL;
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if (ring->tail == &ring->addr[ring->size-1]) {
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ring->tail = &ring->addr[0];
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} else {
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ring->tail++;
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}
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}
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OPAL_THREAD_UNLOCK(&(ring->lock));
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return (void*)p;
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}
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END_C_DECLS
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#endif /* OPAL_RING_BUFFER_H */
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