add pmtiles writer implementation

python/bin/mbtiles2pmtiles

@@ -1,3 +1,26 @@
 #!/usr/bin/env python
 
-print("mbtiles2pmtiles")
+import sys
+import sqlite3
+from pmtiles.writer import write
+
+if len(sys.argv) <= 2:
+    print("Usage: mbtiles2pmtiles MBTILES_FILE PMTILES_FILE")
+    exit(1)
+
+conn = sqlite3.connect(sys.argv[1])
+cursor = conn.cursor()
+
+with write(sys.argv[2]) as writer:
+    for row in cursor.execute('SELECT zoom_level,tile_column,tile_row,tile_data FROM tiles ORDER BY zoom_level,tile_column,tile_row ASC'):
+        writer.write_tile(row[0],row[1],row[2],row[3])
+
+    metadata = {}
+    for row in cursor.execute('SELECT name,value FROM metadata'):
+        metadata[row[0]] = row[1]
+    result = writer.finalize(metadata)
+    print("Num tiles:",result['num_tiles'])
+    print("Num unique tiles:",result['num_unique_tiles'])
+    print("Num leaves:",result['num_leaves'])
+
+conn.close()