availiable memory in JCOP31
hello guys.... i need some help.
I am using jcop31 and i try to get the memory availiable in my card with this code
short m = JCSystem.getAvailableMemory(JCSystem.MEMORY_TYPE_PERSISTENT);
then i create the following class to give me the short m in apdu
private void rd_memory(APDU apdu) {
byte[] buffer = apdu.getBuffer();
short le = apdu.setOutgoing();apdu.setOutgoingLength((byte)2);
buffer[0] = (byte)(m >> 8);
buffer[1] = (byte)(m & 0xFF);
apdu.sendBytes((short)0, (short)2);
}
is this code right? i am getting 6FFF......
# 1
Please use the code formatting.
Here is a hint:
short m = JCSystem.getAvailableMemory(JCSystem.MEMORY_TYPE_PERSISTENT); // example: m = 0x1234
buffer[0] = (byte)(m >> 8); // --> buffer[0] = 0x12
buffer[1] = (byte)(m & 0xFF); // --> equivalent to 0x1234 & 0x00FF --> buffer[1]=0x12
You can use the more convinient way to set short and send:
Util.setShort(buffer, (short) 0, m); // instead of buffer[0/1] = ..
apdu.setOutgoingAndSend((short) 0, (short) 2);
Be aware that the JCSystem.getAvailableMemory() method returns a max of 32kB.
Java Card API:
" ..
If the number of available bytes is greater than 32767, then this method returns 32767. "
# 2
thank you for your replay
when i am using this code:
private void rd_memory(APDU apdu) {
short m = JCSystem.getAvailableMemory(JCSystem.MEMORY_TYPE_PERSISTENT);
byte[] buffer = apdu.getBuffer();
short le = apdu.setOutgoing();
if ( le < 2 )
ISOException.throwIt
(ISO7816.SW_WRONG_LENGTH);
apdu.setOutgoingLength((byte)2);
buffer[0] = (byte)(m >> 8);
buffer[1] = (byte)(m & 0xFF);
apdu.sendBytes((short)0, (short)2);
}
i am getting 7D 90 90 00 as a result
i try to put Util.setShort(buffer, (short) 0, m); // instead of buffer[0/1]
and the result was 7D 9C 90 00
is this ok?
