#include "modbus_encoder.h" //======================================= Modbus Encoder API ====================================// static const unsigned char BinToAscTab[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' }; static const unsigned char CRCTblHi[] = { 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40 }; static const unsigned char CRCTblLo[] = { 0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3, 0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26, 0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5, 0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C, 0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83, 0x41, 0x81, 0x80, 0x40 }; /** * 计算累加和校验 * * @author LXZ (2018-12-03) * * @param dat * @param length * * @return unsigned char */ static unsigned char modbus_calc_lrc(unsigned char *dat, int length) { unsigned char lrc = 0; while (length > 0) { length--; lrc += *dat; dat++; } return (~lrc) + 1; } /** * 计算累加和校验 * * @author LXZ (2018-12-03) * * @param dat * @param length * * @return unsigned char */ static unsigned short modbus_calc_crc(unsigned char *dat, int length) { unsigned char lo = 0xff, hi = 0xff; unsigned char index = 0; while (length > 0) { length--; index = hi ^ (*dat); hi = lo ^ CRCTblHi[index]; lo = CRCTblLo[index]; dat++; } return 0x0100 * lo + hi; } /** * rtu协议的编码 * * @author lxz * * @param dst 目标存放缓冲 * @param src 原始包数据 * @param length 数据长度 * * @return int 解码后的有效长度 */ static int modbus_encoder_rtu_encode(unsigned char *dst, unsigned char *src, int length) { unsigned short crc = modbus_calc_crc(src, length); //需要时就复制源数据 if (dst != src) { int index = 0; while (index < length) { dst[index] = src[index]; index++; } } dst[length++] = crc; dst[length++] = crc >> 8; return length; } /** * 读写长度修正 * * @author lxz * * @param dir 方向，解码是0，编码是1 * @param length 源长度 * * @return int */ static int modbus_endcoder_rtu_length_calc(int dir, int length) { if (dir) { length = length + 2; } else { length = length - 2; } return length; } /** * rtu协议的解码 * * @author lxz * * @param dst 目标存放缓冲 * @param src 原始包数据 * @param length 数据长度 * * @return int 编码后的长度 */ static int modbus_encoder_rtu_decode(unsigned char *dst, unsigned char *src, int length) { if (length < 4) { return -1; } if (modbus_calc_crc(src, length) == 0) { //需要时就复制源数据 if (dst != src) { int index = 0; while (index < length) { dst[index] = src[index]; index++; } } return length - 2; } return 0; } /** * ascii协议的编码 * * @author lxz * * @param dst 目标存放缓冲 * @param src 原始包数据 * @param length 数据长度 * * @return int 解码后的有效长度 */ static int modbus_encoder_ascii_encode(unsigned char *dst, unsigned char *src, int length) { int index = length * 2 + 1; //计算累加和 unsigned char lrc = modbus_calc_lrc(src, length); //从后面编码可以保证前面不会被覆盖 while (length > 0) { length--; dst[(length << 1) + 1] = BinToAscTab[(src[length] >> 4) & 0x0f]; dst[(length << 1) + 2] = BinToAscTab[src[length] & 0x0f]; } //首字节肯定是':' dst[0] = ':'; /** * 加上结尾 */ dst[index++] = BinToAscTab[(lrc >> 4) & 0x0f]; dst[index++] = BinToAscTab[lrc & 0x0f]; dst[index++] = 0x0D; dst[index++] = 0x0A; return index; } /** * ascii读写长度修正 * * @author lxz * * @param dir 方向，解码是0，编码是1 * @param length 源长度 * * @return int */ static int modbus_endcoder_ascii_length_calc(int dir, int length) { if (dir) { length = length * 2 + 5; } else { length = (length - 5) / 2; } return length; } /** * ascii协议的解码 * * @author lxz * * @param dst 目标存放缓冲 * @param src 原始包数据 * @param length 数据长度 * * @return int 编码后的长度 */ static int modbus_encoder_ascii_decode(unsigned char *dst, unsigned char *src, int length) { int index = 0; int res = 0; unsigned char dat = 0; //不符合长度与格式要求不能进行解码 if (length < 9) { return -1; } if (*src != ':' || src[length - 1] != 0x0A || src[length - 2] != 0x0D) { return -2; } //跳掉 ':' src++; length -= 3; //Ascii 解码成hex while (length > 1) { dat = 0; if (*src >= 'A' && *src <= 'F') { dat = *src - 'A' + 10; } else if (*src >= '0' && *src <= '9') { dat = *src - '0'; } src++; dat <<= 4; if (*src >= 'A' && *src <= 'F') { dat |= *src - 'A' + 10; } else if (*src >= '0' && *src <= '9') { dat |= *src - '0'; } src++; length -= 2; dst[index] = dat; index++; } //校验通过 if (modbus_calc_lrc(dst, index) == 0) { res = index; } return res; } static const modbus_encoder_t modbus_rtu_encoder = { modbus_encoder_rtu_encode, modbus_encoder_rtu_decode, modbus_endcoder_rtu_length_calc }; static const modbus_encoder_t modbus_ascii_encoder = { modbus_encoder_ascii_encode, modbus_encoder_ascii_decode, modbus_endcoder_ascii_length_calc }; /** * 根据给定的类型数据缓冲来获取一个匹配的编码器，匹配原则是第一个字节，如果是':'并且最后两个字节是0x0D与0x0A * 刚返回ASCII，否则就返回RTU * * @author lxz * * @param buffer * @param length * * @return modbus_encoder_t* */ modbus_encoder_t * modbus_encoder_match(unsigned char * buffer,int length) { if (length < 4) { return 0; } if (buffer[0] == ':' && buffer[length - 2] == 0x0D && buffer[length - 1] == 0x0A) { return (modbus_encoder_t * )&modbus_ascii_encoder; } return (modbus_encoder_t * )&modbus_rtu_encoder; } /** * 根据编号获取编码器，0是ASCII,1是RTU * * @author lxz * * @param no * * @return modbus_encoder_t* */ modbus_encoder_t * modbus_encoder_get(int no) { if (no == MODBUS_ENCODER_ASCII) { return (modbus_encoder_t * )&modbus_ascii_encoder; } else if (no == MODBUS_ENCODER_RTU) { return (modbus_encoder_t * )&modbus_rtu_encoder; } return 0; }