def __init__(self, buf, offset = 0, idmap = None, idmap_size = 1024):
if idmap is None:
idmap = Cache(idmap_size)
self.offset = offset
if offset != 0:
self.buf = buf = buffer(buf, offset)
else:
self.buf = buf
self.total_size, self.index_offset, self.index_elements = self._Header.unpack_from(buf, 0)
self.index = numpy.frombuffer(buf,
offset = self.index_offset,
dtype = numpy.uint64,
count = self.index_elements)
self.idmap = idmap
if self.index_elements > 0 and self.index[0] >= (self._Header.size + self._NewHeader.size):
# New version, most likely
self.version, min_reader_version, self.schema_offset, self.schema_size = self._NewHeader.unpack_from(
buf, self._Header.size)
if self._CURRENT_VERSION < min_reader_version:
raise ValueError((
"Incompatible buffer, this buffer needs a reader with support for version %d at least, "
"this reader supports up to version %d") % (
min_reader_version,
self._CURRENT_VERSION
))
if self.schema_offset and self.schema_size:
if self.schema_offset > len(buf) or (self.schema_size + self.schema_offset) > len(buf):
raise ValueError("Corrupted input - bad schema location")
stored_schema = cPickle.loads(bytes(buffer(buf, self.schema_offset, self.schema_size)))
if not isinstance(stored_schema, Schema):
raise ValueError("Corrupted input - unrecognizable schema")
if self.schema is None or not self.schema.compatible(stored_schema):
self.schema = stored_schema
elif self.schema is None:
raise ValueError("Cannot map schema-less buffer without specifying schema")
elif self.index_elements > 0:
raise ValueError("Cannot reliably map version-0 buffers")
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