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Diffstat (limited to 'libsparse/include/sparse/sparse.h')
-rw-r--r-- | libsparse/include/sparse/sparse.h | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/libsparse/include/sparse/sparse.h b/libsparse/include/sparse/sparse.h new file mode 100644 index 0000000..db06884 --- /dev/null +++ b/libsparse/include/sparse/sparse.h @@ -0,0 +1,134 @@ +/* + * Copyright (C) 2012 The Android Open Source Project + * + * 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. + */ + +#ifndef _LIBSPARSE_SPARSE_H_ +#define _LIBSPARSE_SPARSE_H_ + +#include <stdbool.h> +#include <stdint.h> + +struct sparse_file; + +/** + * sparse_file_new - create a new sparse file cookie + * + * @block_size - minimum size of a chunk + * @len - size of the expanded sparse file. + * + * Creates a new sparse_file cookie that can be used to associate data + * blocks. Can later be written to a file with a variety of options. + * block_size specifies the minimum size of a chunk in the file. The maximum + * size of the file is 2**32 * block_size (16TB for 4k block size). + * + * Returns the sparse file cookie, or NULL on error. + */ +struct sparse_file *sparse_file_new(unsigned int block_size, int64_t len); + +/** + * sparse_file_destroy - destroy a sparse file cookie + * + * @s - sparse file cookie + * + * Destroys a sparse file cookie. After destroy, all memory passed in to + * sparse_file_add_data can be freed by the caller + */ +void sparse_file_destroy(struct sparse_file *s); + +/** + * sparse_file_add_data - associate a data chunk with a sparse file + * + * @s - sparse file cookie + * @data - pointer to data block + * @len - length of the data block + * @block - offset in blocks into the sparse file to place the data chunk + * + * Associates a data chunk with a sparse file cookie. The region + * [block * block_size : block * block_size + len) must not already be used in + * the sparse file. If len is not a multiple of the block size the data + * will be padded with zeros. + * + * The data pointer must remain valid until the sparse file is closed or the + * data block is removed from the sparse file. + * + * Returns 0 on success, negative errno on error. + */ +int sparse_file_add_data(struct sparse_file *s, + void *data, unsigned int len, unsigned int block); + +/** + * sparse_file_add_fill - associate a fill chunk with a sparse file + * + * @s - sparse file cookie + * @fill_val - 32 bit fill data + * @len - length of the fill block + * @block - offset in blocks into the sparse file to place the fill chunk + * + * Associates a chunk filled with fill_val with a sparse file cookie. + * The region [block * block_size : block * block_size + len) must not already + * be used in the sparse file. If len is not a multiple of the block size the + * data will be padded with zeros. + * + * Returns 0 on success, negative errno on error. + */ +int sparse_file_add_fill(struct sparse_file *s, + uint32_t fill_val, unsigned int len, unsigned int block); + +/** + * sparse_file_add_file - associate a chunk of a file with a sparse file + * + * @s - sparse file cookie + * @filename - filename of the file to be copied + * @file_offset - offset into the copied file + * @len - length of the copied block + * @block - offset in blocks into the sparse file to place the file chunk + * + * Associates a chunk of an existing file with a sparse file cookie. + * The region [block * block_size : block * block_size + len) must not already + * be used in the sparse file. If len is not a multiple of the block size the + * data will be padded with zeros. + * + * Allows adding large amounts of data to a sparse file without needing to keep + * it all mapped. File size is limited by available virtual address space, + * exceptionally large files may need to be added in multiple chunks. + * + * Returns 0 on success, negative errno on error. + */ +int sparse_file_add_file(struct sparse_file *s, + const char *filename, int64_t file_offset, unsigned int len, + unsigned int block); + +/** + * sparse_file_write - write a sparse file to a file + * + * @s - sparse file cookie + * @fd - file descriptor to write to + * @gz - write a gzipped file + * @sparse - write in the Android sparse file format + * @crc - append a crc chunk + * + * Writes a sparse file to a file. If gz is true, the data will be passed + * through zlib. If sparse is true, the file will be written in the Android + * sparse file format. If sparse is false, the file will be written by seeking + * over unused chunks, producing a smaller file if the filesystem supports + * sparse files. If crc is true, the crc of the expanded data will be + * calculated and appended in a crc chunk. + * + * Returns 0 on success, negative errno on error. + */ +int sparse_file_write(struct sparse_file *s, int fd, bool gz, bool sparse, + bool crc); + +#endif |