Finding incorrect implementation of JudyArray - c++11

Question

I'm trying to give a better error report (possible bug) for this case (about judySArray give incorrect result, but I don't know which key that give incorrect result).
The code here from this folder, note on this blog. Dependencies: judySArray.h and cedar.h
// judy.cpp
#include "deps/judySArray.h"
#include <string>
#include <iostream>
#include <cstdlib>
#include <cstring>
using namespace std;
typedef judySArray<double> MSD;
const int MAX_DATA = 12000000;
const char i2ch[] = {'0','1','2','3','4','5','6','7','8','9','a','B','c','D','e','F'};
int get_first_digit(double d) {
while(d > 10) d /= 10;
return d;
}
string to_rhex(int v) {
char hex[32];
int start = 0;
while(v>0) {
hex[start] = i2ch[v%16];
v /= 16;
++start;
}
hex[start] = 0;
return hex;
}
void add_or_inc(MSD &m, const string& key,double set, double inc, int& ctr) {
const char* cstr = key.c_str();
double it = m.find(cstr);
if(!it) {
m.insert(cstr,set);
return;
}
m.insert(cstr,it+inc);
++ctr;
}
int main() {
MSD m(64);
int dup1 = 0, dup2 = 0, dup3 = 0;
for(int z=MAX_DATA;z>0;--z) {
int val2 = MAX_DATA-z;
int val3 = MAX_DATA*2-z;
string key1 = to_string(z);
string key2 = to_string(val2);
string key3 = to_rhex(val3);
add_or_inc(m,key1,z,val2,dup1);
add_or_inc(m,key2,val2,val3,dup2);
add_or_inc(m,key3,val3,z,dup3);
}
cout << dup1 << ' ' << dup2 << ' ' << dup3 << endl;
int total = 0, verify = 0, count = 0;
for(auto &it = m.begin();m.success(); m.next()) {
total += get_first_digit(it.value);
verify += strlen((const char *) it.key);
count += 1;
}
cout << total << ' ' << verify << ' ' << count << endl;
}
other implementation (map, unordered_map, hat-trie and cedar) give correct result:
6009354 6009348 611297
36186112 159701682 23370001
but judy didn't:
6009354 6009348 611297
36186112 159701681 23370000
The problem is, which key that have incorrect result?
I've tried to build a code that insert those keys on another data structure (that is cedar), but that incorrect keys still not detected:
// judy.cpp
#include "deps/judySArray.h"
#include <string>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <vector>
using namespace std;
typedef judySArray<double> MSD;
const int MAX_DATA = 12000000;
const char i2ch[] = {'0','1','2','3','4','5','6','7','8','9','a','B','c','D','e','F'};
int get_first_digit(double d) {
while(d > 10) d /= 10;
return d;
}
string to_rhex(int v) {
char hex[32];
int start = 0;
while(v>0) {
hex[start] = i2ch[v%16];
v /= 16;
++start;
}
hex[start] = 0;
return hex;
}
void add_or_inc(MSD &m, const string& key,double set, double inc, int& ctr) {
const char* cstr = key.c_str();
double it = m.find(cstr);
if(!it) {
m.insert(cstr,set);
return;
}
m.insert(cstr,it+inc);
++ctr;
}
#include "deps/cedar.h"
class MSD2 {
public:
vector<double> data;
typedef cedar::da<int> CI;
CI da;
bool exists(const string& key,double &old) {
int idx = -1;
bool found = da.exactMatchExists(key.c_str(),key.size(),&idx);
if(found) old = data[idx];
return found;
}
void insert(const string& key,double val) {
da.update(key.c_str(),key.size(),data.size());
data.push_back(val);
}
void update(const string& key,double val) {
int idx = -1;
bool found = da.exactMatchExists(key.c_str(),key.size(),&idx);
if(found) {
data[idx] = val;
return;
}
insert(key,val);
}
};
void add_or_inc(MSD2 &m, const string& key,double set, double inc, int& ctr) {
double old;
if(!m.exists(key,old)) {
m.insert(key,set);
return;
}
m.update(key,old+inc);
++ctr;
}
int main() {
MSD m(64);
MSD2 m2;
int dup1 = 0, dup2 = 0, dup3 = 0;
int vup1 = 0, vup2 = 0, vup3 = 0;
for(int z=MAX_DATA;z>0;--z) {
int val2 = MAX_DATA-z;
int val3 = MAX_DATA*2-z;
string key1 = to_string(z);
string key2 = to_string(val2);
string key3 = to_rhex(val3);
add_or_inc(m,key1,z,val2,dup1);
add_or_inc(m,key2,val2,val3,dup2);
add_or_inc(m,key3,val3,z,dup3);
add_or_inc(m2,key1,z,val2,vup1);
add_or_inc(m2,key2,val2,val3,vup2);
add_or_inc(m2,key3,val3,z,vup3);
}
cout << dup1 << ' ' << dup2 << ' ' << dup3 << endl;
cout << vup1 << ' ' << vup2 << ' ' << vup3 << endl;
int total = 0, verify = 0, count = 0;
int xotal = 0, xerify = 0, xount = 0;
union { int i; int x; } b;
size_t from = 0, p = 0;
char key[256] = {0};
for (b.i = m2.da.begin(from, p); b.i != MSD2::CI::CEDAR_NO_PATH; b.i = m2.da.next(from, p)) {
double it2 = m2.data[b.x]; // <-- find cedar's
xotal += get_first_digit(it2);
m2.da.suffix(key,p,from);
xerify += strlen(key);
xount += 1;
double it = m.find(key); // <-- find judy's
if(it != it2) { // if value doesn't match, print:
cout << "mismatch value for " << key << " : " << it2 << " vs " << it << endl;
}
}
for(auto &it = m.begin();m.success(); m.next()) {
total += get_first_digit(it.value);
verify += strlen((const char *) it.key);
count += 1;
}
cout << total << ' ' << verify << ' ' << count << endl;
cout << xotal << ' ' << xerify << ' ' << xount << endl;
}
compile with: clang++ -std=c++11 judy-findbug.cpp (or g++ -std=c++11)
the output would be:
6009354 6009348 611297
6009354 6009348 611297
36186112 159701681 23370000 <-- judy's
36186112 159701682 23370001 <-- cedar's
cedar has one more value than judy's (that is correct), but it didn't detected by the code above..
How to find that incorrect key(s)?

Answer 1

The bug on the code is someone (me) uncomment the assert(value != 0).
The bug was Karl's Judy implementation should not store null values (0 value).
Solution: use Doug Baskins' Judy implementation.