InputStream reading trouble

I have the following problem: I have to read from an InputStream a sequence of data but due its own arrangement I need to read the first 4 bytes as an unsigned short (16 bits) so in this way I will read two blocks of two bytes because the meaning of those bytes are numbers开发者_StackOverflow社区 but after that I need to read as an unsigned byte because the meaning of all the remaining data is ASCII.

Someone could advice me on how to accomplish that?

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You can use java's own DataInputStream. You can read the first 4 bytes by using readInt, the rest using just readByte... See http://download.oracle.com/javase/6/docs/api/java/io/DataInputStream.html

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There's no unsigned short in Java, all numbers in java are signed, you will need an int to store an unsigned short. and as @chicharo pointed out, an unsigned short will only occupy 2 bytes of memory, not 4 bytes.

The following code will do what you want:

int number = inputStream.read() | (intputStream.read() << 8);
byte[] buffer = new byte[2048];
int lenRead = 0;
while ((lenRead = inputStream.read(buffer)) != -1) {
    // write lenRead bytes each time to somewhere, like a ByteArrayOutputStream..
    ......
}

Note: I assumed you wrote your number in that order that lower bits get written first.