gonzui

    1: /*
    2:  *----------------------------------------------------------------------
    3:  *    micro T-Kernel 3.00.00
    4:  *
    5:  *    Copyright (C) 2006-2019 by Ken Sakamura.
    6:  *    This software is distributed under the T-License 2.1.
    7:  *----------------------------------------------------------------------
    8:  *
    9:  *    Released by TRON Forum(http://www.tron.org) at 2019/12/11.
   10:  *
   11:  *----------------------------------------------------------------------
   12:  */
   13: 
   14: /*
   15:  *      queue.h
   16:  *
   17:  *      Queuing operation
   18:  */
   19: 
   20: #ifndef __SYS_QUEUE_H__
   21: #define __SYS_QUEUE_H__
   22: 
   23: #include <tk/tkernel.h>
   24: 
   25: #ifdef __cplusplus
   26: extern "C" {
   27: #endif
   28: 
   29: /*
   30:  * Double-link queue (ring)
   31:  */
   32: typedef struct queue {
   33:         struct queue   *next;
   34:         struct queue   *prev;
   35: } QUEUE;
   36: 
   37: /*
   38:  * Queue initialization 
   39:  */
   40: Inline void QueInit( QUEUE *que )
   41: {
   42:         que->next = (struct queue *)que;
   43:         que->prev = (struct queue *)que;
   44: }
   45: 
   46: /*
   47:  * TRUE if the queue is empty 
   48:  */
   49: Inline BOOL isQueEmpty( QUEUE *que )
   50: {
   51:         return ( que->next == que )? TRUE: FALSE;
   52: }
   53: 
   54: /*
   55:  * Insert in queue 
   56:  *      Inserts entry directly prior to que 
   57:  */
   58: Inline void QueInsert( QUEUE *entry, QUEUE *que )
   59: {
   60:         entry->prev = (struct queue*) que->prev;
   61:         entry->next = que;
   62:         que->prev->next = entry;
   63:         que->prev = entry;
   64: }
   65: 
   66: /*
   67:  * Delete from queue 
   68:  *      Deletes entry from queue 
   69:  *      No action is performed if entry is empty. 
   70:  */
   71: Inline void QueRemove( QUEUE *entry )
   72: {
   73:         if ( entry->next != entry ) {
   74:                 entry->prev->next = (struct queue*) entry->next;
   75:                 entry->next->prev = (struct queue*) entry->prev;
   76:         }
   77: }
   78: 
   79: /*
   80:  * Remove top entry 
   81:  *      Deletes the entry directly after que from the queue,
   82:  *      and returns the deleted entry.
   83:  *      Returns NULL if que is empty.
   84:  */
   85: Inline QUEUE* QueRemoveNext( QUEUE *que )
   86: {
   87:         QUEUE  *entry;
   88: 
   89:         if ( que->next == que ) {
   90:                 return NULL;
   91:         }
   92: 
   93:         entry = que->next;
   94:         que->next = (struct queue*)entry->next;
   95:         entry->next->prev = que;
   96: 
   97:         return entry;
   98: }
   99: 
  100: #ifdef __cplusplus
  101: }
  102: #endif
  103: #endif /* __SYS_QUEUE_H__ */