ap/app/zte_log_agent/hdlc.c

/**
* 
* @file      hdlc.c
* @brief     
*            This file is part of tools.
*            hdlc encode/decode lib
*            
* @details   
* @author    Tools Team.
* @email     
* @copyright Copyright (C) 2013 Sanechips Technology Co., Ltd.
* @warning   
* @date      2019/02/02
* @version   1.1
* @pre       
* @post      
*            
* @par       
* Change History :
* ---------------------------------------------------------------------------
* date        version  author         description
* ---------------------------------------------------------------------------
* 2013/01/21  1.0      lu.xieji       Create file
* 2019/02/02  1.1      jiang.fenglin  ÐÞ¸Ä×¢ÊÍ·½Ê½Îªdoxygen
* ---------------------------------------------------------------------------
* 
* 
*/


#include "log_agent.h"

#define HDLC_CONTROL_CHAR   0x7E  // ½áÊø·û
#define HDLC_ESC_CHAR       0x7D  // תÒë×Ö·ûÖµ
#define HDLC_ESC_MASK       0x20  // תÒëÔËËãÖµ
#define HDLC_TAIL_SIZE      3     // β²¿Ìí¼Ó×Ö·û³¤¶È

// CRC table for 16 bit CRC, with generator polynomial 0x8408, calculated 8 bits at a time, LSB first.
#define CRC_TAB_SIZE        256   // 2^CRC_TAB_BITS
#define CRC_16_L_SEED       0xFFFF
#define CRC_16_L_POLYNOMIAL 0x8408
#define CRC_16_L_OK         0x0F47

#define CRC_16_L_STEP(xx_crc, xx_c) \
	(((xx_crc) >> 8) ^ crc_16_l_table[((xx_crc) ^ (xx_c)) & 0x00ff])

const unsigned short crc_16_l_table[CRC_TAB_SIZE] =
{
    0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
    0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
    0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
    0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
    0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
    0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
    0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
    0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
    0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
    0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
    0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
    0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
    0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
    0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
    0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
    0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
    0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
    0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
    0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
    0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
    0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
    0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
    0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
    0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
    0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
    0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
    0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
    0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
    0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
    0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
    0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
    0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};


/**
* @brief HDLC±àÂë
* @param[out] dest Ä¿±êT_HDLC_BUFFER_TYPEÖ¸Õë
* @param[in] src Ô´T_HDLC_BUFFER_TYPEÖ¸Õë
* @return ³É¹¦·µ»ØTRUE£»Ê§°Ü·µ»ØFALSE
* @note
* @see 
*/
BOOL hdlc_encode(T_HDLC_BUFFER_TYPE *dest, const T_HDLC_BUFFER_TYPE *src)
{
    if (dest && src && dest->buf && src->buf \
            && dest->bufSize > dest->bufIndex && src->bufSize > src->bufIndex)
    {
        unsigned char *dest_buf	= dest->buf + dest->bufIndex;
        unsigned char *src_buf	= src->buf + src->bufIndex;
        unsigned char src_byte = 0;
        unsigned short crc = CRC_16_L_SEED;
        unsigned int converted_length = 0;
        unsigned int i, src_length;
        src_length = src->bufSize - src->bufIndex;

        for (i = 0; i < src_length; i++)
        {
            src_byte = src_buf[i];

            if ((src_byte == HDLC_CONTROL_CHAR) || (src_byte == HDLC_ESC_CHAR))
            {
                crc = CRC_16_L_STEP(crc, src_byte);
                dest_buf[converted_length++] = HDLC_ESC_CHAR;
                dest_buf[converted_length++] = src_byte ^ HDLC_ESC_MASK;
            }
            else
            {
                crc = CRC_16_L_STEP(crc, src_byte);
                dest_buf[converted_length++] = src_byte;
            }
        }

        crc = ~crc;
        //  ¶ÔµÚÒ»¸öunsigned charµÄcrc½øÐÐתÒë
        src_byte = (crc & 0xFF);

        if ((src_byte == HDLC_CONTROL_CHAR) || (src_byte == HDLC_ESC_CHAR))
        {
            dest_buf[converted_length++] = HDLC_ESC_CHAR;
            dest_buf[converted_length++] = src_byte ^ HDLC_ESC_MASK;
        }
        else
        {
            dest_buf[converted_length++] = src_byte;
        }

        // ¶ÔµÚ¶þ¸öunsigned charµÄcrc½øÐÐתÒë
        src_byte = (crc >> 8);

        if ((src_byte == HDLC_CONTROL_CHAR) || (src_byte == HDLC_ESC_CHAR))
        {
            dest_buf[converted_length++] = HDLC_ESC_CHAR;
            dest_buf[converted_length++] = src_byte ^ HDLC_ESC_MASK;
        }
        else
        {
            dest_buf[converted_length++] = src_byte;
        }

        // Ìí¼Ó½áÊø·û
        dest_buf[converted_length++] = HDLC_CONTROL_CHAR;
        dest->bufIndex = converted_length;
        return TRUE;
    }
    else
    {
        return FALSE;
    }
}

/**
* @brief 16λcrcУÑé¼ÆË㣬
* @param[in] buf_ptr ´ýУÑéÊý¾ÝÖ¸Õë
* @param[in] len ´ýУÑéÊý¾Ý³¤¶È
* @return crcУÑéÖµ£¬Èç¹ûbuf_ptr×îºóÁ½Î»°üº¬ÁËУÑ飬½«·µ»ØCRC_16_L_OK
* @note
* @see 
*/
unsigned short crc_16_l_calc(unsigned char *buf_ptr, unsigned int len)
{
    unsigned short crc_16;

    for (crc_16 = CRC_16_L_SEED ; len >= 8; len -= 8, buf_ptr++)
    {
        crc_16 = crc_16_l_table[(crc_16 ^ *buf_ptr) & 0x00ff ] ^ (crc_16 >> 8);
    }

    return(~crc_16);
}


/**
* @brief HDLC½âÂë
* @param[out] dest Ä¿±êT_HDLC_BUFFER_TYPEÖ¸Õë
* @param[in] src Ô´T_HDLC_BUFFER_TYPEÖ¸Õë
* @return ³É¹¦·µ»ØTRUE£»Ê§°Ü·µ»ØFALSE
* @note
* @see 
*/
BOOL hdlc_decode(T_HDLC_BUFFER_TYPE *dest, T_HDLC_BUFFER_TYPE *src)
{
    if (dest != NULL && src != NULL && dest->buf != NULL && src->buf != NULL &&
            src->bufSize > src->bufIndex && dest->bufSize > dest->bufIndex)
    {
        unsigned char *dest_buf	= dest->buf + dest->bufIndex;
        unsigned char *src_buf	= src->buf + src->bufIndex;
        unsigned int dest_length = dest->bufSize - dest->bufIndex;
        unsigned int src_length  = src->bufSize - src->bufIndex;

        unsigned char src_byte = 0;
        unsigned int converted_length = 0;
        BOOL findEnd = FALSE;
        unsigned int i;

        for (i = 0; i < src_length; i++)
        {
            src_byte = src_buf[i];

            if (src_byte == HDLC_ESC_CHAR)
            {
                if (i == (src_length - 1))
                {
                    break;
                }
                else
                {
                    dest_buf[converted_length++] = src_buf[++i] ^ HDLC_ESC_MASK;
                }
            }
            else if (src_byte == HDLC_CONTROL_CHAR)
            {
                dest_buf[converted_length++] = src_byte;
                i++;
                findEnd = TRUE;
                break;
            }
            else
            {
                dest_buf[converted_length++] = src_byte;
            }

            if (converted_length >= dest_length)
            {
                i++;
                break;
            }
        }

        src->bufIndex += i;
        dest->bufIndex += converted_length;

        if (findEnd)
        {
            unsigned short crc = crc_16_l_calc(dest->buf, (dest->bufIndex - 1) * 8);

            if (crc == CRC_16_L_OK)
            {
                dest->bufIndex -= HDLC_TAIL_SIZE;
            }
            else
            {
                dest->bufIndex = 0;
                findEnd = FALSE;
            }
        }

        return findEnd;
    }
    else
    {
        return FALSE;
    }
}