286 lines
10 KiB
C
286 lines
10 KiB
C
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/*
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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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#ifdef __cplusplus
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extern "C" {
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#endif
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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_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 fd 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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* The fd must remain open until the sparse file is closed or the fd block is
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* 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_fd(struct sparse_file *s,
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int fd, int64_t file_offset, unsigned int len, 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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/**
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* sparse_file_len - return the length of a sparse file if written to disk
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*
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* @s - sparse file cookie
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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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* Returns the size a sparse file would be on disk if it were written in the
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* specified format. If sparse is true, this is the size of the data in the
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* sparse format. If sparse is false, this is the size of the normal
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* non-sparse file.
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*/
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int64_t sparse_file_len(struct sparse_file *s, bool sparse, bool crc);
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/**
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* sparse_file_callback - call a callback for blocks in sparse file
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*
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* @s - sparse file cookie
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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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* @write - function to call for each block
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* @priv - value that will be passed as the first argument to write
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*
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* Writes a sparse file by calling a callback function. If sparse is true, the
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* file will be written in the Android sparse file format. If crc is true, the
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* crc of the expanded data will be calculated and appended in a crc chunk.
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* The callback 'write' will be called with data and length for each data,
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* and with data==NULL to skip over a region (only used for non-sparse format).
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* The callback should return negative on error, 0 on success.
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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_callback(struct sparse_file *s, bool sparse, bool crc,
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int (*write)(void *priv, const void *data, int len), void *priv);
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/**
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* sparse_file_read - read a file into a sparse file cookie
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*
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* @s - sparse file cookie
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* @fd - file descriptor to read from
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* @sparse - read a file in the Android sparse file format
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* @crc - verify the crc of a file in the Android sparse file format
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*
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* Reads a file into a sparse file cookie. If sparse is true, the file is
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* assumed to be in the Android sparse file format. If sparse is false, the
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* file will be sparsed by looking for block aligned chunks of all zeros or
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* another 32 bit value. If crc is true, the crc of the sparse file will be
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* verified.
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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_read(struct sparse_file *s, int fd, bool sparse, bool crc);
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/**
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* sparse_file_import - import an existing sparse file
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*
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* @s - sparse file cookie
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* @verbose - print verbose errors while reading the sparse file
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* @crc - verify the crc of a file in the Android sparse file format
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*
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* Reads an existing sparse file into a sparse file cookie, recreating the same
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* sparse cookie that was used to write it. If verbose is true, prints verbose
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* errors when the sparse file is formatted incorrectly.
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*
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* Returns a new sparse file cookie on success, NULL on error.
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*/
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struct sparse_file *sparse_file_import(int fd, bool verbose, bool crc);
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/**
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* sparse_file_import_auto - import an existing sparse or normal file
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*
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* @fd - file descriptor to read from
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* @crc - verify the crc of a file in the Android sparse file format
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* @verbose - whether to use verbose logging
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*
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* Reads an existing sparse or normal file into a sparse file cookie.
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* Attempts to determine if the file is sparse or not by looking for the sparse
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* file magic number in the first 4 bytes. If the file is not sparse, the file
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* will be sparsed by looking for block aligned chunks of all zeros or another
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* 32 bit value. If crc is true, the crc of the sparse file will be verified.
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*
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* Returns a new sparse file cookie on success, NULL on error.
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*/
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struct sparse_file *sparse_file_import_auto(int fd, bool crc, bool verbose);
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/** sparse_file_resparse - rechunk an existing sparse file into smaller files
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*
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* @in_s - sparse file cookie of the existing sparse file
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* @max_len - maximum file size
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* @out_s - array of sparse file cookies
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* @out_s_count - size of out_s array
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*
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* Splits chunks of an existing sparse file into smaller sparse files such that
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* each sparse file is less than max_len. Returns the number of sparse_files
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* that would have been written to out_s if out_s were big enough.
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*/
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int sparse_file_resparse(struct sparse_file *in_s, unsigned int max_len,
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struct sparse_file **out_s, int out_s_count);
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/**
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* sparse_file_verbose - set a sparse file cookie to print verbose errors
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*
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* @s - sparse file cookie
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*
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* Print verbose sparse file errors whenever using the sparse file cookie.
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*/
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void sparse_file_verbose(struct sparse_file *s);
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/**
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* sparse_print_verbose - function called to print verbose errors
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*
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* By default, verbose errors will print to standard error.
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* sparse_print_verbose may be overridden to log verbose errors somewhere else.
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*
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*/
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extern void (*sparse_print_verbose)(const char *fmt, ...);
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#ifdef __cplusplus
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}
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#endif
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#endif
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