128 Bit bitmap operations

I had to maintain a '128 bit' bitmap with

• set
• clear
• is_set 

operations , what came to my head was (128 / 8) = 16

ie if i declare

'unsigned char bitmap[16]'

Q. Why didn't i choose (128 / 32) = 4 ?

A.  if the code  be portable across other platforms, '8 bit' should be a logical choice , as most lower ended arch at most 8 bit.

Now to the code .

//Version 1
void bitmap8_set_bit(unsigned char *bitmap, unsigned int bit)
{
*bitmap |= (1 << bit);
}

void bitmap8_clr_bit(unsigned char *bitmap, unsigned int bit)
{
*bitmap &= (0xff & ~(1 << bit));
}

int bitmap8_is_bit_set(unsigned char *bitmap, unsigned int bit)
{
return ( ( (*bitmap) & (1 << bit) ) ? 1 : 0 );
}

//Version 2
void bitmap8_set_bit(unsigned char *bitmap, unsigned int bit)
{
bitmap[bit / 8] |= (1 << (bit % 8));
}

void bitmap8_clr_bit(unsigned char *bitmap, unsigned int bit)
{
bitmap[bit / 8] &= (0xff & ~(1 << (bit % 8)));
}

int bitmap8_is_bit_set(unsigned char *bitmap, unsigned int bit)
{
return ( (bitmap[bit / 8] & (1 << (bit % 8)) ) ? 1 : 0 );
}

int bitmap8_next_free_bit(unsigned char *bitmap)
{
register int i;

for (i = 0;i < 128; i++) {
if (0 == is_bit_set(bitmap, i))
return i;
}
return i;
}

Q. What is the big deal in the Version 2 ?

Declared 'unsigned char bitmap[16]' , i have to properly index the bitmap array to get the desired result, but the fundamental operation remains the same.

ie bitmap[bit / 8] -> would for bit = 16 would map to bitmap[2]

(bit % 8) -> (16 % 8) = 0 ,

which is exactly what we want.

Local Data address Does not belong to any of this hosts local interfaces

byte[] ip = new byte[4];
        ip[0] = (byte) 192;
        ip[1] = (byte) 168;
        ip[2] = (byte) 1;
        ip[3] = (byte) 8;
SessionAddress localSessionAddr = new SessionAddress(
                InetAddress.getByAddress(ip), LOCAL_RTP_PORT);

Throws: Local Data Address Does not belong to any of this hosts local interfaces

Solution and Cause

The problem is JMF seems to use InetAddress.getAllByName() which gives (in most cases) only single IP address as it may not be in the /etc/hosts. It can be sorted out by setting your interface ip (say eth0, wlan0) in /etc/hosts [1].

>  cat /etc/hosts> 127.0.0.1 localhost> 127.0.1.1 noor> 192.168.1.8 noor