// for general width and height, if(buf & 0x80) == 0, then the next byte does not need to fetch again
// first step, readBufCount = 1 , read int(4 bytes) to buf, if buf & 0x80 !=0, the buf need to continue to fetch
// second step, readBufCount = 2, read next( 4 bytes) to buf, if buf & 0x80 == 0, then assigned the buf to target
// for general width and height, if(buf & 0x80) == 0, then the next byte does not need to fetch again
// first step, readBufCount = 1 , read int(4 bytes) to buf, if buf & 0x80 !=0, the buf need to continue to fetch
// second step, readBufCount = 2, read next( 4 bytes) to buf, if buf & 0x80 == 0, then assigned the buf to target