Diff: mbutils.cpp

Revision:

0:0453a0a7e500

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbutils.cpp	Thu Apr 15 12:10:34 2010 +0000
@@ -0,0 +1,141 @@
+/* 
+ * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
+ * Copyright (c) 2006 Christian Walter <wolti@sil.at>
+ * 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
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ * File: $Id: mbutils.c,v 1.6 2007/02/18 23:49:07 wolti Exp $
+ */
+
+/* ----------------------- System includes ----------------------------------*/
+#include "stdlib.h"
+#include "string.h"
+
+/* ----------------------- Platform includes --------------------------------*/
+#include "port.h"
+
+/* ----------------------- Modbus includes ----------------------------------*/
+#include "mb.h"
+#include "mbproto.h"
+
+/* ----------------------- Defines ------------------------------------------*/
+#define BITS_UCHAR      8U
+
+/* ----------------------- Start implementation -----------------------------*/
+void
+xMBUtilSetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits,
+                UCHAR ucValue )
+{
+    USHORT          usWordBuf;
+    USHORT          usMask;
+    USHORT          usByteOffset;
+    USHORT          usNPreBits;
+    USHORT          usValue = ucValue;
+
+    assert( ucNBits <= 8 );
+    assert( ( size_t )BITS_UCHAR == sizeof( UCHAR ) * 8 );
+
+    /* Calculate byte offset for first byte containing the bit values starting
+     * at usBitOffset. */
+    usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR );
+
+    /* How many bits precede our bits to set. */
+    usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR );
+
+    /* Move bit field into position over bits to set */
+    usValue <<= usNPreBits;
+
+    /* Prepare a mask for setting the new bits. */
+    usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 );
+    usMask <<= usBitOffset - usByteOffset * BITS_UCHAR;
+
+    /* copy bits into temporary storage. */
+    usWordBuf = ucByteBuf[usByteOffset];
+    usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR;
+
+    /* Zero out bit field bits and then or value bits into them. */
+    usWordBuf = ( USHORT )( ( usWordBuf & ( ~usMask ) ) | usValue );
+
+    /* move bits back into storage */
+    ucByteBuf[usByteOffset] = ( UCHAR )( usWordBuf & 0xFF );
+    ucByteBuf[usByteOffset + 1] = ( UCHAR )( usWordBuf >> BITS_UCHAR );
+}
+
+UCHAR
+xMBUtilGetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits )
+{
+    USHORT          usWordBuf;
+    USHORT          usMask;
+    USHORT          usByteOffset;
+    USHORT          usNPreBits;
+
+    /* Calculate byte offset for first byte containing the bit values starting
+     * at usBitOffset. */
+    usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR );
+
+    /* How many bits precede our bits to set. */
+    usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR );
+
+    /* Prepare a mask for setting the new bits. */
+    usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 );
+
+    /* copy bits into temporary storage. */
+    usWordBuf = ucByteBuf[usByteOffset];
+    usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR;
+
+    /* throw away unneeded bits. */
+    usWordBuf >>= usNPreBits;
+
+    /* mask away bits above the requested bitfield. */
+    usWordBuf &= usMask;
+
+    return ( UCHAR ) usWordBuf;
+}
+
+eMBException
+prveMBError2Exception( eMBErrorCode eErrorCode )
+{
+    eMBException    eStatus;
+
+    switch ( eErrorCode )
+    {
+        case MB_ENOERR:
+            eStatus = MB_EX_NONE;
+            break;
+
+        case MB_ENOREG:
+            eStatus = MB_EX_ILLEGAL_DATA_ADDRESS;
+            break;
+
+        case MB_ETIMEDOUT:
+            eStatus = MB_EX_SLAVE_BUSY;
+            break;
+
+        default:
+            eStatus = MB_EX_SLAVE_DEVICE_FAILURE;
+            break;
+    }
+
+    return eStatus;
+}