135 lines
4.7 KiB
C
135 lines
4.7 KiB
C
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _LIBSPARSE_SPARSE_H_
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#define _LIBSPARSE_SPARSE_H_
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#include <stdbool.h>
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#include <stdint.h>
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struct sparse_file;
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/**
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* sparse_file_new - create a new sparse file cookie
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*
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* @block_size - minimum size of a chunk
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* @len - size of the expanded sparse file.
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*
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* Creates a new sparse_file cookie that can be used to associate data
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* blocks. Can later be written to a file with a variety of options.
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* block_size specifies the minimum size of a chunk in the file. The maximum
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* size of the file is 2**32 * block_size (16TB for 4k block size).
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*
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* Returns the sparse file cookie, or NULL on error.
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*/
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struct sparse_file *sparse_file_new(unsigned int block_size, int64_t len);
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/**
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* sparse_file_destroy - destroy a sparse file cookie
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*
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* @s - sparse file cookie
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*
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* Destroys a sparse file cookie. After destroy, all memory passed in to
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* sparse_file_add_data can be freed by the caller
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*/
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void sparse_file_destroy(struct sparse_file *s);
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/**
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* sparse_file_add_data - associate a data chunk with a sparse file
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*
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* @s - sparse file cookie
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* @data - pointer to data block
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* @len - length of the data block
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* @block - offset in blocks into the sparse file to place the data chunk
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*
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* Associates a data chunk with a sparse file cookie. The region
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* [block * block_size : block * block_size + len) must not already be used in
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* the sparse file. If len is not a multiple of the block size the data
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* will be padded with zeros.
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*
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* The data pointer must remain valid until the sparse file is closed or the
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* data block is removed from the sparse file.
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*
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* Returns 0 on success, negative errno on error.
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*/
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int sparse_file_add_data(struct sparse_file *s,
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void *data, unsigned int len, unsigned int block);
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/**
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* sparse_file_add_fill - associate a fill chunk with a sparse file
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*
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* @s - sparse file cookie
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* @fill_val - 32 bit fill data
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* @len - length of the fill block
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* @block - offset in blocks into the sparse file to place the fill chunk
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*
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* Associates a chunk filled with fill_val with a sparse file cookie.
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* The region [block * block_size : block * block_size + len) must not already
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* be used in the sparse file. If len is not a multiple of the block size the
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* data will be padded with zeros.
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*
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* Returns 0 on success, negative errno on error.
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*/
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int sparse_file_add_fill(struct sparse_file *s,
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uint32_t fill_val, unsigned int len, unsigned int block);
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/**
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* sparse_file_add_file - associate a chunk of a file with a sparse file
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*
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* @s - sparse file cookie
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* @filename - filename of the file to be copied
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* @file_offset - offset into the copied file
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* @len - length of the copied block
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* @block - offset in blocks into the sparse file to place the file chunk
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*
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* Associates a chunk of an existing file with a sparse file cookie.
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* The region [block * block_size : block * block_size + len) must not already
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* be used in the sparse file. If len is not a multiple of the block size the
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* data will be padded with zeros.
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*
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* Allows adding large amounts of data to a sparse file without needing to keep
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* it all mapped. File size is limited by available virtual address space,
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* exceptionally large files may need to be added in multiple chunks.
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*
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* Returns 0 on success, negative errno on error.
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*/
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int sparse_file_add_file(struct sparse_file *s,
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const char *filename, int64_t file_offset, unsigned int len,
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unsigned int block);
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/**
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* sparse_file_write - write a sparse file to a file
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*
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* @s - sparse file cookie
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* @fd - file descriptor to write to
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* @gz - write a gzipped file
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* @sparse - write in the Android sparse file format
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* @crc - append a crc chunk
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*
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* Writes a sparse file to a file. If gz is true, the data will be passed
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* through zlib. If sparse is true, the file will be written in the Android
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* sparse file format. If sparse is false, the file will be written by seeking
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* over unused chunks, producing a smaller file if the filesystem supports
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* sparse files. If crc is true, the crc of the expanded data will be
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* calculated and appended in a crc chunk.
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*
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* Returns 0 on success, negative errno on error.
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*/
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int sparse_file_write(struct sparse_file *s, int fd, bool gz, bool sparse,
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bool crc);
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#endif
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