Re: writing bytes (int val 0-255) to file

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sat, 20 Oct 2007 09:29:53 -0400
Message-ID:
<O7GdnXIK_qdMn4fanZ2dnUVZ_oaonZ2d@comcast.com>
chuck <noemail@gmail.com> wrote, quoted or indirectly quoted someone who said :

I am having problems writing any value greater than 127 (out of ascii
range), i get random values.


Roedy Green wrote:

See http://mindprod.com/jgloss/unsigned.html

bytes are -127..+127.


Also,

String encryptedString = padString(Long.toBinaryString(value[i]), -32, "0");
String bs0 = encryptedString.substring(0, 7+1);
int eByte0 = Integer.parseInt( bs0, 2);


Let's say value[i] is 33L. Long.toBinaryString() of that returns "100001".
You failed to show us padString(), but we'll assume that the result of that
operation is
"0000000000000000000000100001" (not long enough to represent a Long, BTW).

Now you parseInt() that String in base 2, which should yield the int value
corresponding to the binary string, which is the original value of 'value[i]'
if the latter is within the int range, an error if it's not.

Despite the name, eByte0 is an int.

So if value[i] is, say, 1023, then eByte0 when it's done will be 1023.

outfile.write( eByte0 );


will then write the string "1023" to the file.

You might as well have just said, "outfile.write( value[i] )". That at least
would handle the long values larger than Integer.MAX_VALUE.

--
Lew

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