private final static int KEY_S2 = 1;

private final static int KEY_S3 = 2;

private final static int KEY_S4 = 4;

private static byte gKbdChars[] = {

'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T',

'U','V','W','X','Y','Z','0','1','2','3','4','5','6','7','8','9','?','_','.',','

};

private static int getKeys(){

int ret = 0;

if(!UC.gpioIsHi(2, 2)) ret += KEY_S2;

if(!UC.gpioIsHi(2, 3)) ret += KEY_S3;

if(!UC.gpioIsHi(2, 4)) ret += KEY_S4;

return ret;

}

private static int waitKey(){

int i;

while((i = getKeys()) == 0); //wait for press

while(getKeys() != 0); //wait for release

return i;

}

private static byte kbd(){

int first = 0;

int len = gKbdChars.length;

int mid, i;

while(len > 1){

UC.lcdClear();

mid = len / 2;

UC.lcdGotoXY(0, 0);

for(i = 0; i < mid; i++) UC.lcdChar((char)gKbdChars[i + first]);

UC.lcdGotoXY(0, 1);

for(i = mid; i < len; i++) UC.lcdChar((char)gKbdChars[i + first]);

i = waitKey();

if(i == KEY_S2) len = mid;

else if(i == KEY_S3) {

len -= mid;

first += mid;

}

else if(i == KEY_S4){

if(len == gKbdChars.length) return 0; //from tpo level we abort

else{

first = 0; //prom any other level we restart the character

len = gKbdChars.length;

}

}

}

i = gKbdChars[first];

if(i == '_') i = ' ';

return (byte)i;

}

private static byte[] input(){

int i;

byte c;

byte str[] = new byte[0];

while((c = kbd()) != 0){

byte[] tmp = new byte[str.length + 1];

for(i = 0; i < str.length; i++) tmp[i] = str[i];

tmp[str.length] = c;

str = tmp;

}

return str;

}

private static void init(){

UC.gpioSetOutput(2, 2, false);

UC.gpioSetOutput(2, 3, false);

UC.gpioSetOutput(2, 4, false);

UC.gpioSetHi(2, 2, true);

UC.gpioSetHi(2, 3, true);

UC.gpioSetHi(2, 4, true);

if(eeRead16(5) == 0xFFFF){ //no data

eeWrite16(5, 7); //root pointer

eeWrite16(7, 0xFFFF);

eeWrite16(9, 0xFFFF);

eeWriteString(11, new byte[] {'D','O','G'});

}

}

private static void showStr(byte[] str){

int col = 0;

int i;

UC.lcdClear();

UC.lcdGotoXY(0, 0);

for(i = 0; i < str.length; i++) {

UC.lcdChar((char)str[i]);

col++;

if(col == 20) UC.lcdGotoXY(0, 1);

}

}

private static int eeRead16(int addr){

int ret;

ret = ((int)UC.eepromRead(addr + 0)) & 0xFF;

ret <<= 8;

ret += ((int)UC.eepromRead(addr + 1)) & 0xFF;

return ret;

}

private static void eeWrite16(int addr, int val){

UC.eepromWrite(addr + 0, (byte)(val >> 8));

UC.eepromWrite(addr + 1, (byte)(val));

}

private static int eeFindEnd(){

int pos = UC.eepromSize() - 1;

while(pos >= 5 && (((int)UC.eepromRead(pos)) & 0xFF) == 0xFF) pos--;

return pos + 1;

}

private static byte[] eeReadString(int addr){

int i, len = ((int)UC.eepromRead(addr++)) & 0xFF;

byte[] ret = new byte[len];

for(i = 0; i < len; i++) ret[i] = UC.eepromRead(addr++);

return ret;

}

private static void eeWriteString(int addr, byte[] str){

int i;

UC.eepromWrite(addr++, (byte)str.length);

for(i = 0; i < str.length; i++) UC.eepromWrite(addr++,str[i]);

}

public static void main(){

int ptr, pptr = 5;

byte[] str;

int i;

init();

while(true){

ptr = eeRead16(pptr);

str = eeReadString(ptr + 4);

showStr(str);

i = waitKey();

if(eeRead16(ptr + 0) == 0xFFFF && eeRead16(ptr + 2) == 0xFFFF){ //leaf

if(i == KEY_S2) pptr = 5; //all good - restart

else if(i == KEY_S3){ //process new entry

showStr(new byte[]{'E','n','t','e','r',' ','n','e','w',' ','Q',' ','s','t',' ','y','o','u','r',' ','a','n','s','w','=','Y','/','N',' ','m','i','n','e','=','N','/','Y'});

i = waitKey();

if(i == KEY_S2){ //proceed

str = input();

showStr(new byte[]{'E','n','t','e','r',' ','y','o','u','r',' ','a','n','s','w','e','r'});

i = waitKey();

if(i == KEY_S2){ //proceed

byte[] answ = input();

int newOfst;

showStr(new byte[]{'Y','E','S','=','m','y',' ','a','n','s','w','e','r','?'});

i = waitKey();

if(i != KEY_S4){

newOfst = (i == KEY_S2) ? 2 : 0;

i = eeFindEnd();

if(UC.eepromSize() - i >= 4 + answ.length + 1 + 4 + str.length + 1){ //we have space

int newLeaf;

//write new leaf node

newLeaf = i;

eeWrite16(i, 0xFFFF);

eeWrite16(i + 2, 0xFFFF);

eeWriteString(i + 4, answ);

i += 4 + 1+ answ.length;

//write new branch node

eeWrite16(i + newOfst, newLeaf);

eeWrite16(i + 2 - newOfst, ptr);

eeWriteString(i + 4, str);

//re-point parent node to new branch node

eeWrite16(pptr, i);

}

else{

showStr(new byte[]{'O','u','t',' ','o','f',' ','E','E','P','R','O','M'});

waitKey();

}

}

}

}

pptr = 5; //restart

}

}

else{ //branch

if(i == KEY_S2) pptr = ptr;

else if(i == KEY_S3) pptr = ptr + 2;

}

}

}

}