/*
1、TLV简介：
在通信系统中，两个设备之前必然存在消息交互，消息的格式也存在各种编码类型，
本文仅描述TLV编码的消息格式。Type-length-value（TLV）格式中T、L的长度固定，
通常为1-8个4个字节，V的长度不固定，由L的值表示，V的内容也可以嵌套子TLV格式。
举例：假设消息按大端模式存放，T占4个字节，L占2个字节，下面的消息：
 unsigned char pMsg[] = {0x09, 0x00, 0x00, 0x00, 0x04, 0x00, 0x01,0x01,0x01, 0x01}
 T = {0x09, 0x00, 0x00, 0x00}，值为9。
 L = {0x04, 0x00},值为4。
 V = {0x01,0x01,0x01, 0x01} ，长度为4，每个字节的值均为1。
2、代码实现：a、按T的值由小到大排序一个消息（假定消息中不存在T相同的信元）；
             b、在两个消息中查找相同的信元（T、L、V）均相同，并输出信元个数。
       
作者:Socrates
日期:2014-08-05
*/

#include "stdafx.h"
#include 
  
   
#include 
   
     #define TLV_T_LEN (4) #define TLV_L_LEN (2) /*错误码*/ enum _RetCode { ERR = -1, /*失败*/ OK = 0 /*成功*/ }RETCODE; /*信元TLV结构*/ typedef struct _stIE { unsigned int ulTag; /*T*/ unsigned short usLen; /*L*/ unsigned char *pValue; /*V*/ }IE; /*消息链表*/ typedef struct _stMsg { IE ie; struct _stMsg *pNext; }Msg; /* 功能:创建链表 */ int CreateMsgList(Msg *&pList) { pList = (Msg *)malloc(sizeof(Msg)); if (NULL == pList) { return ERR; } memset(&(pList->ie), 0, sizeof(IE)); pList->pNext = NULL; return OK; } /* 功能:销毁链表 */ void DestoryMsgList(Msg *pList) { if (NULL == pList) { return; } Msg *p = pList; while(NULL != p) { p = p->pNext; free(pList); pList = p; } free(pList); pList = NULL; return; } /* 功能:向消息链表中插入信元，并保持按Tag递增 */ int InsertIEToMsgList(Msg *pMsgList, const IE *pIE) { if ((NULL == pMsgList) || (NULL == pIE)) { return ERR; } /*链表销毁时释放*/ Msg *pInsertMsg = (Msg *)malloc(sizeof(Msg)); if (NULL == pInsertMsg) { return ERR; } /*创建链表结点*/ memcpy(&(pInsertMsg->ie), pIE, sizeof(IE)); pInsertMsg->pNext = NULL; /*按Tag递增插入结点，保持链表有序，不带头结点*/ Msg *p = pMsgList; while(NULL != p->pNext) { if ((p->pNext->ie.ulTag) > (pIE->ulTag)) { break; } p = p->pNext; } pInsertMsg->pNext = p->pNext; p->pNext = pInsertMsg; return OK; } /* 功能:获取指定消息中的第一个信元 */ IE *GetIEFromMsg(const unsigned char *pInMsg) { if (NULL == pInMsg) { return NULL; } /*链表销毁时释放*/ IE *pIE = (IE *)malloc(sizeof(IE)); if (NULL == pIE) { return NULL; } memset(pIE, 0, sizeof(IE)); pIE->ulTag = *(unsigned int *)pInMsg; pIE->usLen = *(unsigned short *)(pInMsg + TLV_T_LEN); pIE->pValue = (unsigned char *)(pInMsg + TLV_T_LEN + TLV_L_LEN); return pIE; } /* 功能:构造有序消息链表 */ int CreateSortMsgList(unsigned char *pInMsg, unsigned int ulMsgLen, Msg *&pOutMsgList) { if ((NULL == pInMsg) ||(0 == ulMsgLen)) { return ERR; } /*建立链表*/ if (ERR == CreateMsgList(pOutMsgList)) { return ERR; } unsigned int iTmpMsgLen = 0; IE *pIE = NULL; /*遍历消息，注意获取信元并插入消息链表*/ while(iTmpMsgLen < ulMsgLen) { pIE = GetIEFromMsg(pInMsg); if (NULL == pIE) { return ERR; } if(ERR == InsertIEToMsgList(pOutMsgList, pIE)) { return ERR; } pInMsg += (TLV_T_LEN + TLV_L_LEN + pIE->usLen); iTmpMsgLen += (TLV_T_LEN + TLV_L_LEN + pIE->usLen); } return OK; } /* 功能:消息排序 */ int Sort(unsigned char *pInMsg, unsigned int ulMsgLen, unsigned char *pOutMsg) { if ((NULL == pInMsg) || (NULL == pOutMsg) || (0 == ulMsgLen)) { return ERR; } /*建立有序消息链表*/ unsigned char *pTmp = pOutMsg; Msg *pMsgList = NULL; if (ERR == CreateSortMsgList(pInMsg, ulMsgLen, pMsgList)) { DestoryMsgList(pMsgList); return ERR; } /*输出排序后的消息*/ Msg *pList = pMsgList->pNext; while(NULL != pList) { memcpy(pTmp, &(pList->ie), TLV_T_LEN + TLV_L_LEN); memcpy(pTmp + TLV_T_LEN + TLV_L_LEN, pList->ie.pValue, pList->ie.usLen); pTmp += (TLV_T_LEN + TLV_L_LEN + pList->ie.usLen); pList = pList->pNext; } DestoryMsgList(pMsgList); return OK; } /* 功能:比较两个信元是否相同 */ int IsSameIE(IE *pIE1, IE *pIE2) { if ((NULL == pIE1) || (NULL == pIE2)) { return ERR; } if ((pIE1->ulTag == pIE2->ulTag) && (pIE1->usLen == pIE2->usLen) && (0 == memcmp(pIE1->pValue, pIE2->pValue, pIE1->usLen))) { return OK; } return ERR; } /* 功能:比较两个消息，并输出相同信元个数 */ int CompareMsg(unsigned char *