private long unmarshalUint64(byte[] data, long dest) throws TikaException {
        byte[] temp = new byte[8];
        int i, j;

        if (8 > this.getDataRemained()) {
            throw new TikaException("8 > this.getDataRemained()");
        }

        for (i = 8, j = 7; i > 0; i--) {
            temp[j--] = data[this.getCurrentPlace()];
            this.setCurrentPlace(this.getCurrentPlace() + 1);
        }

        dest = new BigInteger(temp).longValue();
        this.setDataRemained(this.getDataRemained() - 8);
        return dest;
    }
Takes 8 bytes and reverses them

@param data
@param dest
@return
@throws TikaException
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/chm/ChmItsfHeader.java