mirrors/PMTiles
1
0
Fork 0
mirror of https://github.com/protomaps/PMTiles.git synced 2026-02-04 10:51:07 +00:00
Code Issues Packages Projects Releases Wiki Activity

refactor python reader to take a get_bytes function; add reader tests [#38]

Browse Source
This commit is contained in:
Brandon Liu
2022-04-26 16:15:03 +08:00
parent adb6f896a3
commit 3944d27833
4 changed files with 79 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
python/pmtiles/writer.py
View File

@@ -80,20 +80,22 @@ def make_pyramid(tile_entries, start_leaf_offset, max_dir_size=21845):
@contextmanager
def write(fname):
w = Writer(fname)
f = open(fname, "wb")
w = Writer(f)
try:
yield w
finally:
w.close()
f.close()
class Writer:
def __init__(self, fname):
self.f = open(fname, "wb")
def __init__(self, f, max_dir_size):
self.offset = 512000
self.f = f
self.f.write(b"\0" * self.offset)
self.tile_entries = []
self.hash_to_offset = {}
self.max_dir_size = max_dir_size
def write_tile(self, z, x, y, data):
hsh = hash(data)
@@ -107,7 +109,7 @@ class Writer:
self.hash_to_offset[hsh] = self.offset
self.offset = self.offset + len(data)
def write_entry(self, entry):
def _write_entry(self, entry):
if entry.is_dir:
z_bytes = 0b10000000 | entry.z
else:
@@ -118,7 +120,7 @@ class Writer:
self.f.write(entry.offset.to_bytes(6, byteorder="little"))
self.f.write(entry.length.to_bytes(4, byteorder="little"))
def write_header(self, metadata, root_entries_len):
def _write_header(self, metadata, root_entries_len):
self.f.write((0x4D50).to_bytes(2, byteorder="little"))
self.f.write((2).to_bytes(2, byteorder="little"))
metadata_serialized = json.dumps(metadata)
@@ -129,24 +131,23 @@ class Writer:
self.f.write(metadata_serialized.encode("utf-8"))
def finalize(self, metadata={}):
root_dir, leaf_dirs = make_pyramid(self.tile_entries, self.offset)
root_dir, leaf_dirs = make_pyramid(
self.tile_entries, self.offset, self.max_dir_size
)
if len(leaf_dirs) > 0:
for leaf_dir in leaf_dirs:
for entry in leaf_dir:
self.write_entry(entry)
self._write_entry(entry)
self.f.seek(0)
self.write_header(metadata, len(root_dir))
self._write_header(metadata, len(root_dir))
for entry in root_dir:
self.write_entry(entry)
self._write_entry(entry)
return {
"num_tiles": len(self.tile_entries),
"num_unique_tiles": len(self.hash_to_offset),
"num_leaves": len(leaf_dirs),
}
def close(self):
self.f.close()