Re: How to convert image into Hex 2 Dimensional Array?
On 5/8/2013 11:22 AM, Daniel Pitts wrote:
On 5/8/13 6:57 AM, lipska the kat wrote:
On 08/05/13 14:19, Daniele Futtorovic wrote:
On 08/05/2013 10:06, lipska the kat allegedly wrote:
Byte[][] bytes = new Byte[width][height];
Lipska, mind the difference between Byte and byte. That code above is
extremely bad advice.
Why? it's common practice these days to eschew primitives and use
(autoboxing) classes
Common practice where? Cite a credible source or I'll be forced to think
that you are just making up facts to support your mistake. My 4 year
old daughter does that; you want to be more credible than my 4 year old,
don't you?
it's more consistent in OO code and, as I
understand things, post autoboxing, the following two lines are
logically equivalent.
1. Byte[][] bytes = new Byte[width][height];
2. byte[][] bytes = new byte[width][length]
Even ignoring the typos, those are nothing alike.
Auto-boxing is a convenience, but does not make those two things the
same, even by a long shot.
For example, consider what happens when `int x = bytes[0][0];'
immediately follows either of the above. In case 2, it sets x
to zero. In case 1, the JVM throws NullPointerException. That's
not "logically equivalent" in my book!
[...]
Personally my decision on whether to use Byte vs byte would hinge solely
on the question "do I want to store nulls in this?"
Or on "Do I want to put it in a Collection?"
There's also the matter of the memory footprint, even if
"efficiency" is a dirty word in some circles. Version 1 will
use four times (32-bit JVM) or eight times (64-bit) as much
memory as version 2. Image sizes vary, but even a fairly modest
640x480 has 300K pixels -- so using Byte[][] instead of byte[][]
would cost an extra 0.9MB or 2.1MB. Even if I had the desire to
store nulls, a bloat of such proportions would probably prompt
me to use byte[][] and seek another way to represent whatever
I wanted the nulls to stand for.
--
Eric Sosman
esosman@comcast-dot-net.invalid