diff --git a/pool.c b/pool.c
index b84c3a7..6771b1f 100644
--- a/pool.c
+++ b/pool.c
@@ -67,32 +67,6 @@ struct pool_val *pool(struct pool *p, char *s, int type) {
 	return pool1(p, s, type, strcmp);
 }
 
-static long long mangle(long long in) {
-	int i;
-	long long out = 0;
-	for (i = 0; i < 64; i++) {
-		out |= ((in >> i) & 1) << (63 - i);
-	}
-	return out;
-}
-
-static int llcmp(const char *v1, const char *v2) {
-	long long ll1 = mangle(*(long long *) v1);
-	long long ll2 = mangle(*(long long *) v2);
-
-	if (ll1 < ll2) {
-		return -1;
-	} else if (ll1 > ll2) {
-		return 1;
-	} else {
-		return 0;
-	}
-}
-
-struct pool_val *pool_long_long(struct pool *p, long long *s, int type) {
-	return pool1(p, (char *) s, type, llcmp);
-}
-
 void pool_free1(struct pool *p, void (*func)(void *)) {
 	while (p->head != NULL) {
 		if (func != NULL) {
diff --git a/pool.h b/pool.h
index 07f1491..fcb8dcf 100644
--- a/pool.h
+++ b/pool.h
@@ -19,7 +19,6 @@ struct pool {
 
 
 struct pool_val *pool(struct pool *p, char *s, int type);
-struct pool_val *pool_long_long(struct pool *p, long long *val, int type);
 void pool_free(struct pool *p);
 void pool_free_strings(struct pool *p);
 void pool_init(struct pool *p, int n);
diff --git a/tile.cc b/tile.cc
index 73176ab..0fc98f7 100644
--- a/tile.cc
+++ b/tile.cc
@@ -3,6 +3,7 @@
 #include <string>
 #include <stack>
 #include <vector>
+#include <map>
 #include <algorithm>
 #include <stdio.h>
 #include <unistd.h>
@@ -347,10 +348,10 @@ long long write_tile(struct index *start, struct index *end, char *metabase, uns
 	for (line_detail = detail; line_detail >= MIN_DETAIL; line_detail--) {
 		GOOGLE_PROTOBUF_VERIFY_VERSION;
 
-		struct pool keys, values, dup;
+		struct pool keys, values;
 		pool_init(&keys, 0);
 		pool_init(&values, 0);
-		pool_init(&dup, 1);
+		std::map<long long, int> dup;
 
 		double interval = 1;
 		double seq = 0;
@@ -370,11 +371,10 @@ long long write_tile(struct index *start, struct index *end, char *metabase, uns
 				continue;
 			}
 
-			struct pool_val *pv = pool_long_long(&dup, &i->fpos, 0);
-			if (pv->n == 0) {
+			if (dup.count(i->fpos) != 0) {
 				continue;
 			}
-			pv->n = 0;
+			dup.insert(std::pair<long long, int>(i->fpos, 1));
 
 			int t;
 			char *meta = metabase + i->fpos;
@@ -484,7 +484,6 @@ long long write_tile(struct index *start, struct index *end, char *metabase, uns
 
 		pool_free(&keys);
 		pool_free(&values);
-		pool_free(&dup);
 
 		std::string s;
 		std::string compressed;