/usr/lib/python2.7/dist-packages/imposm/parser/pbf/parser.py is in python-imposm-parser 1.0.7+ds-3+b1.
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#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import with_statement
import struct
import sys
import zlib
from marshal import dumps
from imposm.parser.pbf import OSMPBF
SUPPORTED_FEATURES = set(['OsmSchema-V0.6', 'DenseNodes'])
_MEMBERTYPE = {0 : 'node',
1 : 'way',
2 : 'relation'}
class PBFParser(object):
"""
OSM PBF parser.
:param xxx_callback:
callback functions for coords, nodes, ways and relations.
Each callback function gets called with a list of multiple elements.
:param xxx_filter:
functions that can manipulate the tag dictionary.
Nodes and relations without tags will not passed to the callback.
:param marshal:
return the data as a marshaled string
"""
def __init__(self, nodes_callback=None, ways_callback=None,
relations_callback=None, coords_callback=None, nodes_tag_filter=None,
ways_tag_filter=None, relations_tag_filter=None, marshal=False):
self.nodes_callback = nodes_callback
self.ways_callback = ways_callback
self.relations_callback = relations_callback
self.coords_callback = coords_callback
self.nodes_tag_filter = nodes_tag_filter
self.ways_tag_filter = ways_tag_filter
self.relations_tag_filter = relations_tag_filter
self.marshal = marshal
def parse(self, filename, offset, size):
"""
Parse primitive block from `filename`.
:param filename: path to PBF file
:param offset: byte offset of the primitive block to parse
:param size: size in bytes of the primitive block to parse
"""
reader = PrimitiveBlockParser(filename, offset, size)
if self.nodes_callback or self.coords_callback:
self.handle_nodes(reader)
if self.ways_callback:
self.handle_ways(reader)
if self.relations_callback:
self.handle_relations(reader)
def handle_nodes(self, reader):
nodes = []
coords = []
nodes_callback = self.nodes_callback
coords_callback = self.coords_callback
for node in reader.nodes():
if nodes_callback:
if self.nodes_tag_filter:
self.nodes_tag_filter(node[1])
if node[1]:
if self.marshal:
nodes.append((node[0], dumps((node[1], node[2]), 2)))
else:
nodes.append((node[0], node[1], node[2]))
if len(nodes) >= 256:
nodes_callback(nodes)
nodes = []
if coords_callback:
coords.append((node[0], node[2][0], node[2][1]))
if len(coords) >= 512:
coords_callback(coords)
coords = []
if nodes_callback:
nodes_callback(nodes)
if coords_callback:
coords_callback(coords)
def handle_ways(self, reader):
ways = []
for way in reader.ways():
if self.ways_tag_filter:
self.ways_tag_filter(way[1])
# always return ways, might be needed for relations
if self.marshal:
ways.append((way[0], dumps((way[1], way[2]), 2)))
else:
ways.append((way[0], way[1], way[2]))
if len(ways) >= 256:
self.ways_callback(ways)
ways = []
self.ways_callback(ways)
def handle_relations(self, reader):
relations = []
for relation in reader.relations():
if self.relations_tag_filter:
self.relations_tag_filter(relation[1])
if not relation[1]:
continue
if self.marshal:
relations.append((relation[0], dumps((relation[1], relation[2]), 2)))
else:
relations.append((relation[0], relation[1], relation[2]))
if len(relations) >= 256:
self.relations_callback(relations)
relations = []
self.relations_callback(relations)
def decoded_stringtable(stringtable):
result = []
for s in stringtable:
result.append(s.decode('utf-8'))
return result
class PrimitiveBlockParser(object):
"""
Low level PBF primitive block parser.
Parses a single primitive block and handles OSM PBF internals like
dense nodes, delta encoding, stringtables, etc.
:param filename: path to PBF file
:param offset: byte offset of the primitive block to parse
:param size: size in bytes of the primitive block to parse
"""
def __init__(self, filename, blob_pos, blob_size):
self.pos = filename, blob_pos, blob_size
data = read_blob_data(filename, blob_pos, blob_size)
self.primitive_block = OSMPBF.PrimitiveBlock()
self.primitive_block.ParseFromString(data)
self.primitivegroup = self.primitive_block.primitivegroup
self.stringtable = decoded_stringtable(self.primitive_block.stringtable.s)
def __repr__(self):
return '<PrimitiveBlockParser %r>' % (self.pos, )
def _get_tags(self, element, pos):
tags = {}
key = None
value = None
keyflag = False
if pos >= len(element):
return {}, pos
while True:
key_val = element[pos]
pos += 1
if key_val == 0:
break
if not keyflag:
key = key_val
keyflag = True
else:
value = key_val
tags[self.stringtable[key]] = self.stringtable[value]
keyflag = False
return tags, pos
def nodes(self):
"""
Return an iterator for all *nodes* in this primitive block.
:rtype: iterator of ``(osm_id, tags, (lon, lat))`` tuples
"""
for group in self.primitivegroup:
dense = group.dense
if dense:
granularity = self.primitive_block.granularity or 100
lat_offset = self.primitive_block.lat_offset or 0
lon_offset = self.primitive_block.lon_offset or 0
coord_scale = 0.000000001
get_tags = self._get_tags
ids = dense.id
lats = dense.lat
lons = dense.lon
keys_vals = dense.keys_vals
last_id = last_lat = last_lon = last_keysvals_pos = 0
for i in xrange(len(ids)):
last_id += ids[i]
last_lat += coord_scale * (lat_offset + (granularity * lats[i]))
last_lon += coord_scale * (lon_offset + (granularity * lons[i]))
tags, last_keysvals_pos = get_tags(keys_vals, last_keysvals_pos)
yield (last_id, tags, (last_lon, last_lat))
nodes = group.nodes
if nodes:
for node in nodes:
keys, vals = node.keys, node.vals
tags = []
for i in xrange(len(keys)):
tags.append((self.stringtable[keys[i]], self.stringtable[vals[i]]))
yield (node.id, tags, (node.lon, node.lat))
def ways(self):
"""
Return an iterator for all *ways* in this primitive block.
:rtype: iterator of ``(osm_id, tags, [ref1, ref2, ...])`` tuples
"""
for group in self.primitivegroup:
ways = group.ways
if ways:
for way in ways:
keys = way.keys
vals = way.vals
delta_refs = way.refs
tags = {}
for i in xrange(len(keys)):
tags[self.stringtable[keys[i]]] = self.stringtable[vals[i]]
refs = []
ref = 0
for delta in delta_refs:
ref += delta
refs.append(ref)
yield (way.id, tags, refs)
def relations(self):
"""
Return an iterator for all *relations* in this primitive block.
:rtype: iterator of ``(osm_id, tags, [(ref1, type, role), ...])`` tuples
"""
for group in self.primitivegroup:
relations = group.relations
if relations:
for relation in relations:
members = []
memids = relation.memids
rel_types = relation.types
roles_sids = relation.roles_sid
keys = relation.keys
vals = relation.vals
memid = 0
for i in xrange(len(rel_types)):
memid += memids[i]
members.append((memid, _MEMBERTYPE[rel_types[i]], self.stringtable[roles_sids[i]]))
tags = {}
for i in xrange(len(keys)):
tags[self.stringtable[keys[i]]] = self.stringtable[vals[i]]
yield (relation.id, tags, members)
class PBFHeader(object):
def __init__(self, filename, blob_pos, blob_size):
data = read_blob_data(filename, blob_pos, blob_size)
self.header_block = OSMPBF.HeaderBlock()
self.header_block.ParseFromString(data)
def required_features(self):
return set(self.header_block.required_features)
def read_blob_data(filename, blob_pos, blob_size):
"""
Returns the (unzipped) blob data from filename and position.
"""
with open(filename, 'rb') as f:
f.seek(blob_pos)
blob_data = f.read(blob_size)
blob = OSMPBF.Blob()
blob.ParseFromString(blob_data)
raw_data = blob.raw
if raw_data:
return raw_data
return zlib.decompress(blob.zlib_data)
import time
class PBFFile(object):
"""
OSM PBF file reader.
Parses the low-level file structure with header sizes,
offsets and blob headers.
:param filename: path to the PBF file
"""
def __init__(self, filename):
self.filename = filename
self.file = open(filename, 'rb')
self.next_blob_pos = self.prev_blob_pos = 0
header_offsets = self._skip_header()
self.header = PBFHeader(self.filename, header_offsets['blob_pos'], header_offsets['blob_size'])
self.check_features()
def check_features(self):
missing_features = self.header.required_features().difference(SUPPORTED_FEATURES)
if missing_features:
raise NotImplementedError(
'%s requires features not implemented by this parser: %s' %
(self.filename, ', '.join(missing_features))
)
def _skip_header(self):
return self.blob_offsets().next()
def seek(self, pos):
self.next_blob_pos = pos
def rewind(self):
self.next_blob_pos = self.prev_blob_pos
def blob_offsets(self):
"""
Returns an iterator of the blob offsets in this file.
Each offsets is stored in a dictionary with:
- `filename` the path of this PBF file.
- `blob_pos` the byte offset
- `blob_size` the size of this blob in bytes
"""
while True:
self.file.seek(self.next_blob_pos)
blob_header_size = self._blob_header_size()
if not blob_header_size: break
blob_size = self._blob_size(self.file.read(blob_header_size))
blob_pos = self.next_blob_pos + 4 + blob_header_size
blob_header_pos=self.next_blob_pos,
prev_blob_header_pos = self.prev_blob_pos
self.prev_blob_pos = self.next_blob_pos
self.next_blob_pos = blob_pos + blob_size
yield dict(blob_pos=blob_pos, blob_size=blob_size,
blob_header_pos=blob_header_pos,
prev_blob_header_pos=prev_blob_header_pos,
filename=self.filename)
def primitive_block_parsers(self):
"""
Returns an iterator of PrimitiveBlockParser.
"""
for pos in self.blob_offsets():
yield PrimitiveBlockParser(self.filename, pos['blob_pos'], pos['blob_size'])
def _blob_size(self, data):
blob_header = OSMPBF.BlobHeader()
blob_header.ParseFromString(data)
return blob_header.datasize
def _blob_header_size(self):
bytes = self.file.read(4)
if bytes:
return struct.unpack('!i', bytes)[0]
return None
def read_pbf(filename):
pbf = PBFFile(filename)
for block in pbf.primitive_block_parsers():
for node in block.nodes():
pass
for way in block.ways():
pass
for relation in block.relations():
pass
if __name__ == '__main__':
from timeit import Timer
n = 1
r = 1
print "reading %s, number of calls: %d, repeat: %d" %(sys.argv[1],n,r)
t = Timer("read_pbf(sys.argv[1])", "from __main__ import read_pbf")
times = t.repeat(r,n)
avrg_times = []
for time in times:
avrg_times.append(time/n)
print "avrg time/call: %f" %(min(avrg_times))
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