Add the ability to tippecanoe-decode a standalone .pbf tile

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.9.4
+
+* Tippecanoe-decode can decode .pbf files that aren't in an .mbtiles container
+
 ## 1.9.3
 
 * Don't get stuck in a loop trying to split up very small, very complicated polygons

README.md

@@ -338,6 +338,7 @@ on an entire file:
 or on an individual tile:
 
     tippecanoe-decode file.mbtiles zoom x y
+    tippecanoe-decode file.vector.pbf zoom x y
 
 If you decode an entire file, you get a nested `FeatureCollection` identifying each
 tile and layer separately. Note that the same features generally appear at all zooms,

decode.cc

@@ -5,6 +5,9 @@
 #include <string>
 #include <zlib.h>
 #include <math.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
 #include <google/protobuf/io/zero_copy_stream_impl_lite.h>
 #include <google/protobuf/io/coded_stream.h>
 #include "vector_tile.pb.h"
@@ -359,6 +362,30 @@ void decode(char *fname, int z, unsigned x, unsigned y) {
 	int oz = z;
 	unsigned ox = x, oy = y;
 
+	int fd = open(fname, O_RDONLY);
+	if (fd >= 0) {
+		struct stat st;
+		if (fstat(fd, &st) == 0) {
+			if (st.st_size < 50 * 1024 * 1024) {
+				char *map = (char *) mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+				if (map != NULL && map != MAP_FAILED) {
+					if (strcmp(map, "SQLite format 3") != 0) {
+						std::string s = std::string(map, st.st_size);
+						handle(s, z, x, y, 1);
+						munmap(map, st.st_size);
+						return;
+					}
+				}
+				munmap(map, st.st_size);
+			}
+		} else {
+			perror("fstat");
+		}
+		close(fd);
+	} else {
+		perror(fname);
+	}
+
 	if (sqlite3_open(fname, &db) != SQLITE_OK) {
 		fprintf(stderr, "%s: %s\n", fname, sqlite3_errmsg(db));
 		exit(EXIT_FAILURE);

man/tippecanoe.1

@@ -399,6 +399,7 @@ or on an individual tile:
 .RS
 .nf
 tippecanoe\-decode file.mbtiles zoom x y
+tippecanoe\-decode file.vector.pbf zoom x y
 .fi
 .RE
 .PP

version.h

@@ -1 +1 @@
-#define VERSION "tippecanoe v1.9.3\n"
+#define VERSION "tippecanoe v1.9.4\n"