diff packages/kernel/current/include/mqueue.hxx @ 115:6ed91473a1cd ecos-sw-2000-08-21

Merge from eCos master repository on 2000-08-21-22:40:54-BST
author jlarmour
date Fri, 25 Aug 2000 17:32:38 +0000
parents
children 678094f34118
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+++ b/packages/kernel/current/include/mqueue.hxx
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+#ifndef CYGONCE_KERNEL_MQUEUE_HXX
+#define CYGONCE_KERNEL_MQUEUE_HXX
+/*========================================================================
+//
+//      mqueue.hxx
+//
+//      Message queues
+//
+//========================================================================
+//####COPYRIGHTBEGIN####
+//                                                                          
+// -------------------------------------------                              
+// The contents of this file are subject to the Red Hat eCos Public License 
+// Version 1.1 (the "License"); you may not use this file except in         
+// compliance with the License.  You may obtain a copy of the License at    
+// http://www.redhat.com/                                                   
+//                                                                          
+// Software distributed under the License is distributed on an "AS IS"      
+// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the 
+// License for the specific language governing rights and limitations under 
+// the License.                                                             
+//                                                                          
+// The Original Code is eCos - Embedded Configurable Operating System,      
+// released September 30, 1998.                                             
+//                                                                          
+// The Initial Developer of the Original Code is Red Hat.                   
+// Portions created by Red Hat are                                          
+// Copyright (C) 1998, 1999, 2000 Red Hat, Inc.                             
+// All Rights Reserved.                                                     
+// -------------------------------------------                              
+//                                                                          
+//####COPYRIGHTEND####
+//========================================================================
+//#####DESCRIPTIONBEGIN####
+//
+// Author(s):     jlarmour
+// Contributors:  
+// Date:          2000-05-09
+// Purpose:       This file provides the interface for eCos message queues
+// Description:   This differs from the message boxes also supported by
+//                eCos primarily because the requirements of message
+//                queues are driven by POSIX semantics. POSIX semantics are
+//                more dynamic and therefore heavyweight than Mboxes,
+//                including prioritization, and variable sized queues and
+//                message lengths
+// Usage:         #include <cyg/kernel/mqueue.hxx>
+//
+//####DESCRIPTIONEND####
+//
+//======================================================================
+*/
+
+/* CONFIGURATION */
+
+#include <pkgconf/kernel.h>          /* Configuration header */
+
+/* INCLUDES */
+
+#include <stddef.h>                  /* size_t */
+#include <cyg/infra/cyg_type.h>      /* Types */
+#include <cyg/infra/cyg_ass.h>       /* CYGDBG_DEFINE_CHECK_THIS,
+                                        CYGDBG_USE_ASSERTS */
+#include <cyg/kernel/sema.hxx>       /* Cyg_Counting_Semaphore */
+
+/* CLASSES */
+
+class Cyg_Mqueue {
+public:
+    typedef void (*callback_fn_t)(Cyg_Mqueue &q, CYG_ADDRWORD data);
+    typedef void * (*qalloc_fn_t)(size_t len);
+    typedef void (*qfree_fn_t)(void *ptr, size_t len);
+
+    typedef enum {
+        OK=0,
+        NOMEM,
+        WOULDBLOCK,
+        INTR
+    } qerr_t;
+
+protected:
+    struct qentry {
+        struct qentry *next;
+        unsigned int priority;
+        size_t buflen;
+        volatile bool busy;
+        // data buffer follows here
+        char *buf() const { return (char *)this + sizeof(*this); }
+    };
+
+    Cyg_Counting_Semaphore putsem, getsem;
+
+    struct qentry *q;            // q entries in use
+    struct qentry *freelist;     // q entries not in use
+    void *queuespace;            // placeholder for the dynamically allocated
+                                 // area
+
+    size_t queuespacesize;
+
+    qfree_fn_t free_fn;          // how to free queuespace when we destruct
+
+    callback_fn_t callback;
+    CYG_ADDRWORD callback_data;
+
+    CYGDBG_DEFINE_CHECK_THIS
+
+#ifdef CYGDBG_USE_ASSERTS
+    long qlen;
+    size_t msgsize;
+#endif
+
+public:
+
+    Cyg_Mqueue( long maxmsgs, long maxmsgsize,
+                qalloc_fn_t qalloc, qfree_fn_t qfree, qerr_t *err );
+    ~Cyg_Mqueue();
+
+    // put() copies len bytes of *buf into the queue at priority prio
+    qerr_t put( const char *buf, size_t len, unsigned int prio,
+                bool block=true);
+
+    // get() returns the oldest highest priority message in the queue in *buf
+    // and sets *prio to the priority (if prio is non-NULL) and *len to the
+    // actual message size
+    qerr_t get( char *buf, size_t *len, unsigned int *prio, bool block=true ); 
+
+    // count() returns the number of messages in the queue
+    long count();
+
+    // Supply a callback function to call (with the supplied data argument)
+    // when the queue goes from empty to non-empty (unless someone's already
+    // doing a get()). This returns the old callback_fn, and if olddata is
+    // non-NULL sets it to the old data (yes, really!)
+    callback_fn_t setnotify( callback_fn_t callback_fn, CYG_ADDRWORD data,
+                             CYG_ADDRWORD *olddata=NULL);
+    
+}; /* class Cyg_Mqueue */
+
+#include <cyg/kernel/mqueue.inl>
+
+#endif /* CYGONCE_KERNEL_MQUEUE_HXX multiple inclusion protection */
+
+/* EOF mqueue.hxx */