【TLV】非递归TLV数据解析

 #include <stdio.h>

 #define X_LEN_OF_TAG_MAX        ( 2 )
 #define X_LEN_OF_LEN_MAX        ( 2 )

 struct st_tlv_t {
     unsigned int TAG;
     unsigned char isCustructed;
     unsigned int valLen;
     unsigned char *pVal;

 };

 static int skipZeroBytes( unsigned char **pcur, unsigned char *end )
 {
     while( **pcur ==  && (*pcur < end) )
         (*pcur)++;

     if( *pcur < end )
         return ;

     return ;
 }

 static int parseTag( unsigned char **pcur, unsigned char *end, struct st_tlv_t *tlv )
 {
     unsigned char *pp;
     int lenOfTag;
     int i;

     if( *pcur >= end )
         return ;

     pp = *pcur;

     lenOfTag = ;
     if( (*pp++ & 0x1f) == 0x1f )
     {
         do {
             if( pp >= end )
                 return ;

             lenOfTag++;
         } while( (*pp++) & 0x80 );
     }
     if( lenOfTag > X_LEN_OF_TAG_MAX )
     {
         return ;
     }

     tlv->isCustructed = ( **pcur & (  <<  ) ) ?  : ;

     tlv->TAG = ;
     for( i = ; i < lenOfTag; i++ )
     {
         tlv->TAG <<= ;
         tlv->TAG |= *(*pcur + i );
     }

     (*pcur) += lenOfTag;
     //printf("tlv->TAG:%x\r\n", tlv->TAG);
     return ;
 }

 static int parseLength( unsigned char **pcur, unsigned char *end, struct st_tlv_t *tlv )
 {
     unsigned char *pp;
     int lenOfLen;
     int i;

     if( *pcur >= end || **pcur ==  )
         return ;

     pp = *pcur;

     if( *pp & 0x80 )
     {
         lenOfLen = *pp & 0x7F;
         if( pp + lenOfLen >= end )
             return ;
         if( lenOfLen > X_LEN_OF_LEN_MAX )
             return ;
         pp++;
         tlv->valLen = ;
         for( i = ; i < lenOfLen; i++ )
         {
             tlv->valLen <<= ;
             tlv->valLen |= *(pp + i );
         }
         (*pcur) += (lenOfLen+);
     }
     else
     {
         tlv->valLen = **pcur;
         (*pcur)++;
     }
     //printf("tlv->valLen:%d\r\n", tlv->valLen);
     return ;
 }

 static int parseValue( unsigned char **pcur, unsigned char *end, struct st_tlv_t *tlv )
 {
     if( (*pcur + tlv->valLen) > end )
         return ;

     tlv->pVal = ( unsigned char *)(*pcur);

     return ;
 }

 int parseTlv( unsigned char *buffer, int length, struct st_tlv_t *tlv )
 {
     unsigned char *cur;
     unsigned char *end;

     cur = buffer;
     end = buffer + length;

     if( !skipZeroBytes( &cur, end ) )
         return ;

     if( !parseTag( &cur, end, tlv ) )
         return ;

     if( !parseLength( &cur, end, tlv ) )
         return ;

     if( !parseValue( &cur, end, tlv ) )
         return ;

     return ;
 }

 int printTlv( struct st_tlv_t *tlv )
 {
     int i;
     printf("\r\n[%x] len:%d\r\n", tlv->TAG, tlv->valLen);
     for( i = ; i < tlv->valLen; i++ )
         printf("%02x", tlv->pVal[i]);
     printf("\r\n");

     return ;
 }

 int parseTlvXXX(  unsigned char *buffer, int length, int reverse )
 {
     unsigned char *cur;
     unsigned char *end;
     struct st_tlv_t tlv;

     cur = buffer;
     end = buffer + length;

     while( cur < end )
     {
         if( !parseTlv( cur, end-cur, &tlv ) )
             return ;

         printTlv( &tlv );

         // 如果是复合型的TAG，则进入复合TAG内部继续分析
         if( tlv.isCustructed && reverse )
         {
             cur = tlv.pVal;
         }
         else // 如果是简单型的TAG，则分析下一个TAG
         {
             cur = tlv.pVal + tlv.valLen;
         }
     }

     if( cur > end )
         return ;

     return ;
 }

 int main( void )
 {
     int ret;

     unsigned char tlv_buf0[] = {
         0x70,0x28,0x61,0x26,0x4f,0x07,0xa0,0x00,
         0x00,0x03,0x33,0x01,0x01,0x50,0x0b,0x50,
         0x42,0x4f,0x43,0x20,0x43,0x72,0x65,0x64,
         0x69,0x74,0x87,0x01,0x01,0x9f,0x12,0x0a,
         0x50,0x42,0x4f,0x43,0x20,0x44,0x45,0x42,
         0x49,0x54,0x90,0x00
     };
     unsigned char tlv_buf1[] = {
         0x00,0x00,0x00,
         0x70,0x81,0x83,0x90,0x81,0x80,0x25,0x3c,
         0x3c,0x1f,0xd9,0x92,0x8d,0x88,0x21,0x11,
         0xa6,0xac,0x4c,0xa2,0x07,0xdf,0x93,0x10,
         0x64,0x23,0x95,0xea,0x09,0x7b,0x3c,0xb1,
         0x6d,0x51,0x76,0x53,0x35,0x38,0x03,0xc2,
         0xc1,0x03,0x3e,0x4a,0xac,0xb9,0x73,0x5d,
         0x2e,0x69,0xca,0x49,0x8f,0xeb,0x4c,0xc0,
         0xae,0xe1,0xff,0xc7,0xf5,0x44,0x83,0x09,
         0x3a,0x30,0xcc,0xbf,0x6b,0x20,0x11,0xd6,
         0x09,0xe5,0x2f,0xd7,0x87,0x76,0xb6,0x6b,
         0x6d,0x86,0x95,0xcb,0xc0,0x46,0x21,0x6b,
         0xf8,0x1c,0x52,0xd5,0xc2,0xf9,0x47,0xde,
         0xe3,0xad,0xd7,0x20,0x9a,0xb3,0x27,0xf2,
         0x9c,0x10,0x6b,0xfa,0x0e,0x29,0x1d,0x9d,
         0xab,0x00,0x91,0x06,0xf4,0x89,0xba,0x59,
         0x43,0x6d,0xa9,0x46,0x75,0xdf,0x9d,0x31,
         0xdc,0xaf,0xbd,0x6a,0xbe,0x20,
     };
     unsigned char tlv_buf2[] = {
         0x6f,0x24,0x84,0x0e,0x31,0x50,0x41,0x59,
         0x2e,0x53,0x59,0x53,0x2e,0x44,0x44,0x46,
         0x30,0x31,0xa5,0x12,0x88,0x01,0x01,0x5f,
         0x2d,0x08,0x7a,0x68,0x65,0x6e,0x66,0x72,
         0x64,0x65,0x9f,0x11,0x01,0x01
     };

     ret = parseTlvXXX( tlv_buf0, sizeof(tlv_buf0),  );
     printf("0-parseTlvXX: %d\r\n", ret);

     ret = parseTlvXXX( tlv_buf1, sizeof(tlv_buf1),  );
     printf("1-parseTlvXX: %d\r\n", ret);

     ret = parseTlvXXX( tlv_buf2, sizeof(tlv_buf2),  );
     printf("2-parseTlvXX: %d\r\n", ret);

     return ;
 }