/* $NetBSD: queue.h,v 1.42 2005/07/13 15:08:24 wiz Exp $ */
/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* 3. 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 REGENTS 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.
*
* @(#)queue.h 8.5 (Berkeley) 8/20/94
*/
/*
*/
#ifndef _SYS_QUEUE_H
#define _SYS_QUEUE_H
#ifdef __cplusplus
extern "C" {
#endif
/*
* This file defines five types of data structures: singly-linked lists,
* lists, simple queues, tail queues, and circular queues.
*
* A singly-linked list is headed by a single forward pointer. The
* elements are singly linked for minimum space and pointer manipulation
* overhead at the expense of O(n) removal for arbitrary elements. New
* elements can be added to the list after an existing element or at the
* head of the list. Elements being removed from the head of the list
* should use the explicit macro for this purpose for optimum
* efficiency. A singly-linked list may only be traversed in the forward
* direction. Singly-linked lists are ideal for applications with large
* datasets and few or no removals or for implementing a LIFO queue.
*
* A list is headed by a single forward pointer (or an array of forward
* pointers for a hash table header). The elements are doubly linked
* so that an arbitrary element can be removed without a need to
* traverse the list. New elements can be added to the list before
* or after an existing element or at the head of the list. A list
* may only be traversed in the forward direction.
*
* A simple queue is headed by a pair of pointers, one the head of the
* list and the other to the tail of the list. The elements are singly
* linked to save space, so elements can only be removed from the
* head of the list. New elements can be added to the list after
* an existing element, at the head of the list, or at the end of the
* list. A simple queue may only be traversed in the forward direction.
*
* A tail queue is headed by a pair of pointers, one to the head of the
* list and the other to the tail of the list. The elements are doubly
* linked so that an arbitrary element can be removed without a need to
* traverse the list. New elements can be added to the list before or
* after an existing element, at the head of the list, or at the end of
* the list. A tail queue may be traversed in either direction.
*
* A circle queue is headed by a pair of pointers, one to the head of the
* list and the other to the tail of the list. The elements are doubly
* linked so that an arbitrary element can be removed without a need to
* traverse the list. New elements can be added to the list before or after
* an existing element, at the head of the list, or at the end of the list.
* A circle queue may be traversed in either direction, but has a more
* complex end of list detection.
*
* For details on the use of these macros, see the queue(3) manual page.
*/
/*
* List definitions.
*/
struct name { \
}
{ NULL }
struct { \
}
/*
* List functions.
*/
#if defined(_KERNEL) && defined(QUEUEDEBUG)
__LINE__);
#else
#endif
} while (0)
} while (0)
} while (0)
} while (0)
} while (0)
(var); \
/*
* List access methods.
*/
/*
* Singly-linked List definitions.
*/
struct name { \
}
{ NULL }
struct { \
}
/*
* Singly-linked List functions.
*/
} while (0)
} while (0)
} while (0)
} while (0)
} \
else { \
} \
} while (0)
/*
* Singly-linked List access methods.
*/
/*
* Singly-linked Tail queue declarations.
*/
struct name { \
}
struct { \
}
/*
* Singly-linked Tail queue functions.
*/
} while (0)
} while (0)
} while (0)
== NULL) \
} while (0)
== NULL) \
} while (0)
} else { \
} \
} while (0)
(var); \
/*
* Singly-linked Tail queue access methods.
*/
/*
* Simple queue definitions.
*/
struct name { \
}
struct { \
}
/*
* Simple queue functions.
*/
} while (0)
} while (0)
} while (0)
} while (0)
} while (0)
} else { \
} \
} while (0)
(var); \
/*
* Simple queue access methods.
*/
/*
* Tail queue definitions.
*/
struct name { \
}
struct { \
}
/*
* Tail queue functions.
*/
#if defined(_KERNEL) && defined(QUEUEDEBUG)
panic("TAILQ_PREREMOVE head %p elm %p %s:%d", \
#else
#endif
} while (0)
else \
} while (0)
} while (0)
else \
} while (0)
} while (0)
else \
} while (0)
(var); \
(var); \
(var) = \
/*
* Tail queue access methods.
*/
/*
* Circular queue definitions.
*/
struct name { \
}
struct { \
}
/*
* Circular queue functions.
*/
} while (0)
else \
} while (0)
else \
} while (0)
else \
} while (0)
else \
} while (0)
else \
else \
} while (0)
/*
* Circular queue access methods.
*/
#ifdef __cplusplus
}
#endif
#endif /* !_SYS_QUEUE_H */