toString causing memory leaks!

ramman345

Hey guys, I'm new to the Javelin and have been using it for a few months. As I've begun more serious testing of my work I discovered that the program halts at the same place after 10-20 minutes. Using the stamp.core.Memory.freeMemory() method suggested in one of the older posts I have worked my program down to the basics of:

while(true)
{
Clear_LCD();
free_memory = stamp.core.Memory.freeMemory();
LCDtx.sendString(Integer.toString(free_memory));
CPU.delay(10000);
}

Each iteration of this loop looses 16 bytes! I think the culprit is the Integer.toString(). Any suggestions or work arounds?
Thanks

Peter Verkaik

The easiest way is to use a StringBuffer object.

StringBuffer buf = new StringBuffer();
while(true)
{
Clear_LCD();
buf.clear();
free_memory = stamp.core.Memory.freeMemory();
buf.append(free_memory);
LCDtx.sendString(buf);
CPU.delay(10000);
}

It is required that your LCDtx.sendString() method accepts a StringBuffer as parameter.
If it doesn't, you must make a method LCDtx.sendString(StringBuf s).

regards peter

ramman345

Peter, LCDtx is a UART VP object. I am using the built in sendString method of the UART class which I don't believe accepts stringBuffers. Any advice?

Peter Verkaik

Add following method to your program

public void lcdSendString(StringBuffer s) {
· int i=s.Length; int j=0;
· while (i > 0) {
··· LCDtx.sendByte(s.charAt(j));
··· j++;
··· i--;
· }
}

and in your program use
lcdSendString(buf);


regards peter

ramman345

Peter, I have done some more testing after following your advice and made the following discovery:

for a StringBuffer s, s.toString() does not use any memory.
for an int i, Integer.toString(i) uses at least 16 bytes of memory every time it is called.

Therefore I have found a compromise between our two codes:

while(true)
{
Clear_LCD();
free_memory = stamp.core.Memory.freeMemory();
s.clear();
s.append("Memory: ");
s.append(free_memory);
LCDtx.sendString(s.toString());
CPU.delay(10000);
}

which does not result in memory loss. Thanks so much for your help, J