There is no function "readLittleEndian" in your code.  Your function "readBufferLittleEndian" does reverse the order of the bytes and under normal conditions will convert a 4-byte little-endian value into uint64_t.

Be aware that the uint64_t value produced need not be big-endian.  Consider a buffer containing four bytes 0x11, 0x22, 0x44, and 0x88 in that order.  Note that the