125 lines
4.0 KiB
Python
125 lines
4.0 KiB
Python
# -*- coding: utf-8 -*-
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; version 2 of the License.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Library General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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import os
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SIZE_UNITS = {
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"b": 1,
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"k": 1024,
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"M": 1024 ** 2,
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"G": 1024 ** 3,
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}
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def convert_media_size(size):
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if isinstance(size, str):
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if size[-1] in SIZE_UNITS:
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num = int(size[:-1])
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units = size[-1]
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else:
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num = int(size)
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units = "b"
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result = num * SIZE_UNITS[units]
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else:
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result = int(size)
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if result <= 0:
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raise ValueError("Media size must be a positive number: %s" % size)
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return result
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def convert_file_size(size, block_size=2048):
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"""round file size to block"""
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blocks = int(size / block_size)
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if size % block_size:
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blocks += 1
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return blocks * block_size
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class MediaSplitter(object):
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"""
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MediaSplitter splits files so that they fit on a media of given size.
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Each file added to the spliter has a size in bytes that will be rounded to
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the nearest multiple of block size. If the file is sticky, it will be
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included on each disk. The files will be on disks in the same order they
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are added; there is no re-ordering. The number of disk is thus not the
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possible minimum.
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"""
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def __init__(self, media_size, compose=None):
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self.media_size = convert_media_size(media_size)
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self.files = [] # to preserve order
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self.file_sizes = {}
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self.sticky_files = set()
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self.compose = compose
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def add_file(self, name, size, sticky=False):
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name = os.path.normpath(name)
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size = int(size)
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old_size = self.file_sizes.get(name, None)
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if old_size is not None and old_size != size:
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raise ValueError("File size mismatch; file: %s; sizes: %s vs %s" % (name, old_size, size))
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if size > self.media_size:
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raise ValueError("File is larger than media size: %s" % name)
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self.files.append(name)
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self.file_sizes[name] = size
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if sticky:
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self.sticky_files.add(name)
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@property
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def total_size(self):
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return sum(self.file_sizes.values())
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@property
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def total_size_in_blocks(self):
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return sum([convert_file_size(i) for i in list(self.file_sizes.values())])
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def split(self, first_disk=0, all_disks=0):
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all_files = []
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sticky_files = []
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sticky_files_size = 0
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for name in self.files:
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if name in self.sticky_files:
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sticky_files.append(name)
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sticky_files_size += convert_file_size(self.file_sizes[name])
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else:
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all_files.append(name)
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disks = []
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disk = {}
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# as it would be on single medium (sticky_files just once)
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total_size_single = sticky_files_size
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while all_files:
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name = all_files.pop(0)
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size = convert_file_size(self.file_sizes[name])
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if not disks or disk["size"] + size > self.media_size:
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disk = {"size": sticky_files_size, "files": sticky_files[:]}
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disks.append(disk)
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disk["files"].append(name)
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disk["size"] += size
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total_size_single += size
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if self.compose:
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self.compose.log_debug("MediaSplitter: free space on single media would be %s. Total size of single medium: %s." % (self.media_size - total_size_single, total_size_single))
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return disks
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