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mbutils.h
00001 /* 00002 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU. 00003 * Copyright (c) 2006 Christian Walter <wolti@sil.at> 00004 * All rights reserved. 00005 * 00006 * Redistribution and use in source and binary forms, with or without 00007 * modification, are permitted provided that the following conditions 00008 * are met: 00009 * 1. Redistributions of source code must retain the above copyright 00010 * notice, this list of conditions and the following disclaimer. 00011 * 2. Redistributions in binary form must reproduce the above copyright 00012 * notice, this list of conditions and the following disclaimer in the 00013 * documentation and/or other materials provided with the distribution. 00014 * 3. The name of the author may not be used to endorse or promote products 00015 * derived from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 00018 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 00019 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 00020 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 00021 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 00022 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00023 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00024 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00025 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 00026 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00027 * 00028 * File: $Id: mbutils.h,v 1.5 2006/12/07 22:10:34 wolti Exp $ 00029 */ 00030 00031 #ifndef _MB_UTILS_H 00032 #define _MB_UTILS_H 00033 00034 #ifdef __cplusplus 00035 PR_BEGIN_EXTERN_C 00036 #endif 00037 /*! \defgroup modbus_utils Utilities 00038 * 00039 * This module contains some utility functions which can be used by 00040 * the application. It includes some special functions for working with 00041 * bitfields backed by a character array buffer. 00042 * 00043 */ 00044 /*! \addtogroup modbus_utils 00045 * @{ 00046 */ 00047 /*! \brief Function to set bits in a byte buffer. 00048 * 00049 * This function allows the efficient use of an array to implement bitfields. 00050 * The array used for storing the bits must always be a multiple of two 00051 * bytes. Up to eight bits can be set or cleared in one operation. 00052 * 00053 * \param ucByteBuf A buffer where the bit values are stored. Must be a 00054 * multiple of 2 bytes. No length checking is performed and if 00055 * usBitOffset / 8 is greater than the size of the buffer memory contents 00056 * is overwritten. 00057 * \param usBitOffset The starting address of the bits to set. The first 00058 * bit has the offset 0. 00059 * \param ucNBits Number of bits to modify. The value must always be smaller 00060 * than 8. 00061 * \param ucValues Thew new values for the bits. The value for the first bit 00062 * starting at <code>usBitOffset</code> is the LSB of the value 00063 * <code>ucValues</code> 00064 * 00065 * \code 00066 * ucBits[2] = {0, 0}; 00067 * 00068 * // Set bit 4 to 1 (read: set 1 bit starting at bit offset 4 to value 1) 00069 * xMBUtilSetBits( ucBits, 4, 1, 1 ); 00070 * 00071 * // Set bit 7 to 1 and bit 8 to 0. 00072 * xMBUtilSetBits( ucBits, 7, 2, 0x01 ); 00073 * 00074 * // Set bits 8 - 11 to 0x05 and bits 12 - 15 to 0x0A; 00075 * xMBUtilSetBits( ucBits, 8, 8, 0x5A); 00076 * \endcode 00077 */ 00078 void xMBUtilSetBits( UCHAR * ucByteBuf, USHORT usBitOffset, 00079 UCHAR ucNBits, UCHAR ucValues ); 00080 00081 /*! \brief Function to read bits in a byte buffer. 00082 * 00083 * This function is used to extract up bit values from an array. Up to eight 00084 * bit values can be extracted in one step. 00085 * 00086 * \param ucByteBuf A buffer where the bit values are stored. 00087 * \param usBitOffset The starting address of the bits to set. The first 00088 * bit has the offset 0. 00089 * \param ucNBits Number of bits to modify. The value must always be smaller 00090 * than 8. 00091 * 00092 * \code 00093 * UCHAR ucBits[2] = {0, 0}; 00094 * UCHAR ucResult; 00095 * 00096 * // Extract the bits 3 - 10. 00097 * ucResult = xMBUtilGetBits( ucBits, 3, 8 ); 00098 * \endcode 00099 */ 00100 UCHAR xMBUtilGetBits( UCHAR * ucByteBuf, USHORT usBitOffset, 00101 UCHAR ucNBits ); 00102 00103 /*! @} */ 00104 00105 #ifdef __cplusplus 00106 PR_END_EXTERN_C 00107 #endif 00108 #endif
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