Update geohash.c

Makefile

@@ -3,8 +3,8 @@
 all: library test
 
 library:
-	gcc -c geohash.c -o geohash.o
-	ar rcs libgeohash.a geohash.o
+	gcc -fPIC -c geohash.c -o geohash.o
+	gcc -shared -o libgeohash.so geohash.o
 	rm geohash.o
 
 test:
@@ -13,4 +13,4 @@ test:
 	rm a.out
 
 clean: 
-	rm -rf *.a *.o
+	rm -rf *.a *.o *.so

geohash.c

@@ -95,23 +95,26 @@ unsigned int index_for_char(char c, char *string) {
     return index;
 }
 
-char* get_neighbor(char *hash, int direction) {
+char* get_neighbor(const char *hash, int direction) {
 
     int hash_length = strlen(hash);
 
-	char last_char = hash[hash_length - 1];
+    char last_char = hash[hash_length - 1];
 
     int is_odd = hash_length % 2;
     char **border = is_odd ? odd_borders : even_borders;
     char **neighbor = is_odd ? odd_neighbors : even_neighbors; 
 
-    char *base = malloc(sizeof(char) * 1);
+    char *base = malloc(sizeof(char) * hash_length + 1);
     base[0] = '\0';
     strncat(base, hash, hash_length - 1);
 
-	if(index_for_char(last_char, border[direction]) != -1)
-		base = get_neighbor(base, direction);
-
+    if(index_for_char(last_char, border[direction]) != -1)
+    {
+        char *newBase = get_neighbor(base, direction);
+        strncpy( base , newBase , hash_length );
+	free( newBase );
+    }
     int neighbor_index = index_for_char(last_char, neighbor[direction]);
     last_char = char_map[neighbor_index];
 
@@ -242,7 +245,7 @@ GeoCoord geohash_decode(char *hash) {
 }
 
 
-char** geohash_neighbors(char *hash) {
+char** geohash_neighbors(const char *hash) {
 
     char** neighbors = NULL;
 

geohash.h

@@ -28,6 +28,10 @@
  *  OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#ifdef __cplusplus
+extern "C" {
+#endif 
+
 // Metric in meters
 typedef struct GeoBoxDimensionStruct {
 
@@ -69,9 +73,14 @@ extern GeoCoord geohash_decode(char* hash);
  *                  N, NE, E, SE, S, SW, W, NW
  * 					0, 1,  2,  3, 4,  5, 6, 7
  */ 
-extern char** geohash_neighbors(char* hash);
+extern char** geohash_neighbors(const char* hash);
 
 /*
  * Returns the width and height of a precision value.
  */
-extern GeoBoxDimension geohash_dimensions_for_precision(int precision);
+extern GeoBoxDimension geohash_dimensions_for_precision(int precision);
+
+
+#ifdef __cplusplus
+}
+#endif