Move feature type to index so point skipping can avoid looking up geometry

Which should avoid having to page the geometry in if there is
more data than will fit in memory

geojson.c

@@ -381,7 +381,6 @@ void read_json(FILE *f, char *fname, char *layername, int maxzoom, int minzoom,
 
 			unsigned bbox[] = { UINT_MAX, UINT_MAX, 0, 0 };
 
-			serialize_int(metafile, mb_geometry[t], &fpos, fname, jp);
 			parse_geometry(t, coordinates, bbox, &fpos, metafile, VT_MOVETO, fname, jp);
 			serialize_int(metafile, VT_END, &fpos, fname, jp);
 
@@ -467,6 +466,7 @@ void read_json(FILE *f, char *fname, char *layername, int maxzoom, int minzoom,
 								ix.index = encode(x << (32 - z), y << (32 - z));
 							}
 							ix.fpos = start;
+							ix.type = mb_geometry[t];
 							ix.maxzoom = z;
 							fwrite_check(&ix, sizeof(struct index), 1, indexfile, fname, jp);
 						}

tile.cc

@@ -376,10 +376,7 @@ long long write_tile(struct index *start, struct index *end, char *metabase, uns
 			}
 			dup.insert(std::pair<long long, int>(i->fpos, 1));
 
-			int t;
-			char *meta = metabase + i->fpos;
-			deserialize_int(&meta, &t);
-
+			int t = i->type;
 			if (t == VT_POINT) {
 				seq++;
 
@@ -390,6 +387,7 @@ long long write_tile(struct index *start, struct index *end, char *metabase, uns
 				}
 			}
 
+			char *meta = metabase + i->fpos;
 			drawvec geom = decode_geometry(&meta, z, tx, ty, line_detail);
 
 			bool reduced = false;

tile.h

@@ -19,8 +19,9 @@ struct pool_val *deserialize_string(char **f, struct pool *p, int type);
 
 struct index {
 	unsigned long long index;
-	long long fpos : 56;
+	long long fpos : 48;
 	int maxzoom : 8;
+	int type : 8;
 };
 
 long long write_tile(struct index *start, struct index *end, char *metabase, unsigned *file_bbox, int z, unsigned x, unsigned y, int detail, int basezoom, struct pool *file_keys, char *layername, sqlite3 *outdb, double droprate, int buffer);