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#ifndef STRING_POOL_HH
#define STRING_POOL_HH
#include <cstdlib>
#include <cstring>
#ifdef __GNUC__
#if __GNUC__ > 2
using namespace std;
#endif
#endif
/******************************************************************************/
/* Class that allocates a const char* if not yet present in string pool */
/******************************************************************************/
// table of all locks a thread is holding
#ifdef HASH_TABLE
#include <hash_set>
#else
#include <set>
#endif
#ifdef HASH_TABLE
struct eqstr
{
bool operator()(const char* s1, const char* s2) const
{
return strcmp(s1, s2) == 0;
}
};
typedef hash_set<const char*, hash<const char*>, eqstr> string_table;
#else
struct ltstr
{
bool operator()(const char* s1, const char* s2) const
{
return strcmp(s1, s2) < 0;
}
};
typedef set<const char*, ltstr> string_table;
#endif
class string_pool {
public:
string_table pool;
const char* add(const char* el) {
char* entry;
string_table::iterator it;
if ((it = pool.find(el)) == pool.end()) {
// allocate element!
entry = strdup(el);
pool.insert(entry);
return const_cast<const char*>(entry);
} else {
return *it;
}
}
void remove(const char* el) {
string_table::iterator entry;
if ((entry = pool.find(el)) != pool.end()) {
// free space for element
free(const_cast<char*>(*entry));
pool.erase(entry);
}
}
void clear() {
for (string_table::iterator it = pool.begin(); it != pool.end(); it++) {
free(const_cast<char*>(*it));
pool.erase(it);
}
}
};
#endif
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