memmove(dst,src,sizeof(PRUnichar)*(aLength-anOffset));
memmove(dst,src,cnt*sizeof(PRUnichar));
void ShiftDoubleCharsLeft(char* aDest,PRUint32 aLength,PRUint32 anOffset,PRUint32 aCount) {   PRUnichar* root=(PRUnichar*)aDest;  PRUnichar* dst = root+anOffset;  PRUnichar* src = root+anOffset+aCount;  memmove(dst,src,sizeof(PRUnichar)*(aLength-anOffset));}