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