int find_key(FILE *f, uint64 key, entry_t *entry){
int first, last, middle;
entry_t first_entry=entry_none, last_entry,middle_entry;
first=-1;
if(fseek(f,-16,SEEK_END)){
*entry=entry_none;
entry->key=key+1; //hack
return -1;
}
last=ftell(f)/16;
entry_from_file(f,&last_entry);
while(1){
if(last-first==1){
*entry=last_entry;
return last;
}
middle=(first+last)/2;
fseek(f,16*middle,SEEK_SET);
entry_from_file(f,&middle_entry);
if(key<=middle_entry.key){
last=middle;
last_entry=middle_entry;
}else{
first=middle;
first_entry=middle_entry;
}
}
}
Move openBookAndGetNextMove(char* file_name, uint64* key){
FILE *f;
entry_t entry;
int offset;
entry_t entries[MAX_MOVES];
int count=0;
int ret, i;
char move_s[6];
int total_weight;
Move lastChosen={0,0};
f=fopen(file_name,"rb");
if(!f){
perror(file_name);
return lastChosen;
}
offset=find_key(f,*key,&entry);
if(entry.key!=*key){
// printf("%016llx: No such key\n",key);
return lastChosen;
}
entries[0]=entry;
count=1;
fseek(f,16*(offset+1),SEEK_SET);
while(1){
ret=entry_from_file(f,&entry);
if(ret){
break;
}
if(entry.key!=*key){
break;
}
if(count==MAX_MOVES){
printf("#Too many moves in this position (max=%d)\n",MAX_MOVES);
return lastChosen;
}
entries[count++]=entry;
}
total_weight=0;
for(i=0;i<count;i++){
total_weight+=entries[i].weight;
}
double weightForChoosing=0;
// srand(clock());
double randomNumber=(double)rand()/RAND_MAX;
for(i=0;i<count;i++){
move_to_string(move_s,entries[i].move);
if(move_s[0]>='a'&&move_s[0]<='h'){
if(move_s[1]>='1'&&move_s[1]<='8'){
if(move_s[2]>='a'&&move_s[2]<='h'){
if(move_s[3]>='1'&&move_s[3]<='8'){
lastChosen.from=(int)(move_s[0]-'a')+0x10*(7-(int)(move_s[1]-'1'));
lastChosen.to=(int)(move_s[2]-'a')+0x10*(7-(int)(move_s[3]-'1'));
if(move_s[4]=='q')
lastChosen.promote=queen;
else if(move_s[4]=='r')
lastChosen.promote=knight;
else if(move_s[4]=='b')
lastChosen.promote=bishop;
else if(move_s[4]=='n')
lastChosen.promote=knight;
}
}
}
}
printf("#move=%s weight=%5.2f%%\n",
move_s,
100*((double) entries[i].weight/ (double) total_weight));
weightForChoosing+=((double) entries[i].weight/ (double) total_weight);
if(weightForChoosing>randomNumber)
break;
}
return lastChosen;
}
