version bump

python/pmtiles/reader.py

@@ -0,0 +1,53 @@
+import json
+import mmap
+from contextlib import contextmanager
+
+@contextmanager
+def read(fname):
+    f = Reader(fname)
+    try:
+        yield f
+    finally:
+        f.close()
+
+class Reader:
+    def __init__(self,fname):
+        self.f = open(fname, "r+b")
+        self.mmap = mmap.mmap(self.f.fileno(), 0)
+        assert int.from_bytes(self.mmap[0:2],byteorder='little') == 0x4D50
+
+        self.root_dir = {}
+        first_entry_idx = 10+self.metadata_len
+        last_entry_idx = first_entry_idx + self.root_entries * 17
+        for i in range(first_entry_idx,last_entry_idx,17):
+            z = int.from_bytes(self.mmap[i:i+1],byteorder='little')
+            x = int.from_bytes(self.mmap[i+1:i+4],byteorder='little')
+            y = int.from_bytes(self.mmap[i+4:i+7],byteorder='little')
+            tile_off = int.from_bytes(self.mmap[i+7:i+13],byteorder='little')
+            tile_len = int.from_bytes(self.mmap[i+13:i+17],byteorder='little')
+            self.root_dir[(z,x,y)] = (tile_off,tile_len)
+
+    def close(self):
+        self.f.close()
+
+    @property
+    def metadata_len(self):
+        return int.from_bytes(self.mmap[4:8],byteorder='little')
+
+    @property
+    def metadata(self):
+        s = self.mmap[10:10+self.metadata_len]
+        return json.loads(s)
+
+    @property
+    def version(self):
+        return int.from_bytes(self.mmap[2:4],byteorder='little')
+
+    @property
+    def root_entries(self):
+        return int.from_bytes(self.mmap[8:10],byteorder='little')
+
+    def get(self,z,x,y):
+        val = self.root_dir.get((z,x,y))
+        if val:
+            return self.mmap[val[0]:val[0]+val[1]]