mindspore2022/mindspore/mindrecord/shardsegment.py

129 lines
4.3 KiB
Python

# Copyright 2019 Huawei Technologies Co., Ltd
#
# 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.
# ==============================================================================
"""
This module is to read page from mindrecord.
"""
import mindspore._c_mindrecord as ms
from mindspore import log as logger
from .shardutils import populate_data, SUCCESS
from .shardheader import ShardHeader
__all__ = ['ShardSegment']
class ShardSegment:
"""
Wrapper class which is represent ShardSegment class in c++ module.
The class would query data from MindRecord File in pagination.
"""
def __init__(self):
self._segment = ms.ShardSegment()
self._header = None
self._columns = None
def open(self, file_name, num_consumer=4, columns=None, operator=None):
"""
Initialize the ShardSegment.
Args:
file_name (str, list[str]): File names of MindRecord File.
num_consumer (int): Number of worker threads which load data in parallel. Default: 4.
columns (list[str]): List of fields which correspond data would be read.
operator(int): Reserved parameter for operators. Default: None.
Returns:
MSRStatus, SUCCESS or FAILED.
Raises:
MRMOpenError: If failed to open MindRecord File.
"""
self._columns = columns if columns else []
operator = operator if operator else []
if isinstance(file_name, list):
load_dataset = False
else:
load_dataset = True
file_name = [file_name]
ret = self._segment.open(file_name, load_dataset, num_consumer, self._columns, operator)
if ret != SUCCESS:
logger.error("Failed to open {}.".format(file_name))
raise MRMOpenError
self._header = ShardHeader(self._segment.get_header())
return ret
def get_category_fields(self):
"""
Get candidate category fields.
Returns:
list[str], by which data could be grouped.
"""
return self._segment.get_category_fields()
def set_category_field(self, category_field):
"""Select one category field to use."""
return self._segment.set_category_field(category_field)
def read_category_info(self):
"""
Get the group info by the current category field.
Returns:
str, description fo group information.
"""
return self._segment.read_category_info()
def read_at_page_by_id(self, category_id, page, num_row):
"""
Get the data of some page by category id.
Args:
category_id (int): Category id, referred to the return of read_category_info.
page (int): Index of page.
num_row (int): Number of rows in a page.
Returns:
list[dict]
Raises:
MRMUnsupportedSchemaError: If schema is invalid.
"""
data = self._segment.read_at_page_by_id(category_id, page, num_row)
return [populate_data(raw, blob, self._columns, self._header.blob_fields,
self._header.schema) for blob, raw in data]
def read_at_page_by_name(self, category_name, page, num_row):
"""
Get the data of some page by category name.
Args:
category_name (str): Category name, referred to the return of read_category_info.
page (int): Index of page.
num_row (int): Number of rows in a page.
Returns:
list[dict]
Raises:
MRMUnsupportedSchemaError: If schema is invalid.
"""
data = self._segment.read_at_page_by_name(category_name, page, num_row)
return [populate_data(raw, blob, self._columns, self._header.blob_fields,
self._header.schema) for blob, raw in data]