sparse.h revision 9e1f17e926fa20255c5f4b4d2f68aa98a964253a
1/* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef _LIBSPARSE_SPARSE_H_ 18#define _LIBSPARSE_SPARSE_H_ 19 20#include <stdbool.h> 21#include <stdint.h> 22 23struct sparse_file; 24 25/** 26 * sparse_file_new - create a new sparse file cookie 27 * 28 * @block_size - minimum size of a chunk 29 * @len - size of the expanded sparse file. 30 * 31 * Creates a new sparse_file cookie that can be used to associate data 32 * blocks. Can later be written to a file with a variety of options. 33 * block_size specifies the minimum size of a chunk in the file. The maximum 34 * size of the file is 2**32 * block_size (16TB for 4k block size). 35 * 36 * Returns the sparse file cookie, or NULL on error. 37 */ 38struct sparse_file *sparse_file_new(unsigned int block_size, int64_t len); 39 40/** 41 * sparse_file_destroy - destroy a sparse file cookie 42 * 43 * @s - sparse file cookie 44 * 45 * Destroys a sparse file cookie. After destroy, all memory passed in to 46 * sparse_file_add_data can be freed by the caller 47 */ 48void sparse_file_destroy(struct sparse_file *s); 49 50/** 51 * sparse_file_add_data - associate a data chunk with a sparse file 52 * 53 * @s - sparse file cookie 54 * @data - pointer to data block 55 * @len - length of the data block 56 * @block - offset in blocks into the sparse file to place the data chunk 57 * 58 * Associates a data chunk with a sparse file cookie. The region 59 * [block * block_size : block * block_size + len) must not already be used in 60 * the sparse file. If len is not a multiple of the block size the data 61 * will be padded with zeros. 62 * 63 * The data pointer must remain valid until the sparse file is closed or the 64 * data block is removed from the sparse file. 65 * 66 * Returns 0 on success, negative errno on error. 67 */ 68int sparse_file_add_data(struct sparse_file *s, 69 void *data, unsigned int len, unsigned int block); 70 71/** 72 * sparse_file_add_fill - associate a fill chunk with a sparse file 73 * 74 * @s - sparse file cookie 75 * @fill_val - 32 bit fill data 76 * @len - length of the fill block 77 * @block - offset in blocks into the sparse file to place the fill chunk 78 * 79 * Associates a chunk filled with fill_val with a sparse file cookie. 80 * The region [block * block_size : block * block_size + len) must not already 81 * be used in the sparse file. If len is not a multiple of the block size the 82 * data will be padded with zeros. 83 * 84 * Returns 0 on success, negative errno on error. 85 */ 86int sparse_file_add_fill(struct sparse_file *s, 87 uint32_t fill_val, unsigned int len, unsigned int block); 88 89/** 90 * sparse_file_add_file - associate a chunk of a file with a sparse file 91 * 92 * @s - sparse file cookie 93 * @filename - filename of the file to be copied 94 * @file_offset - offset into the copied file 95 * @len - length of the copied block 96 * @block - offset in blocks into the sparse file to place the file chunk 97 * 98 * Associates a chunk of an existing file with a sparse file cookie. 99 * The region [block * block_size : block * block_size + len) must not already 100 * be used in the sparse file. If len is not a multiple of the block size the 101 * data will be padded with zeros. 102 * 103 * Allows adding large amounts of data to a sparse file without needing to keep 104 * it all mapped. File size is limited by available virtual address space, 105 * exceptionally large files may need to be added in multiple chunks. 106 * 107 * Returns 0 on success, negative errno on error. 108 */ 109int sparse_file_add_file(struct sparse_file *s, 110 const char *filename, int64_t file_offset, unsigned int len, 111 unsigned int block); 112 113/** 114 * sparse_file_add_file - associate a chunk of a file with a sparse file 115 * 116 * @s - sparse file cookie 117 * @filename - filename of the file to be copied 118 * @file_offset - offset into the copied file 119 * @len - length of the copied block 120 * @block - offset in blocks into the sparse file to place the file chunk 121 * 122 * Associates a chunk of an existing fd with a sparse file cookie. 123 * The region [block * block_size : block * block_size + len) must not already 124 * be used in the sparse file. If len is not a multiple of the block size the 125 * data will be padded with zeros. 126 * 127 * Allows adding large amounts of data to a sparse file without needing to keep 128 * it all mapped. File size is limited by available virtual address space, 129 * exceptionally large files may need to be added in multiple chunks. 130 * 131 * The fd must remain open until the sparse file is closed or the fd block is 132 * removed from the sparse file. 133 * 134 * Returns 0 on success, negative errno on error. 135 */ 136int sparse_file_add_fd(struct sparse_file *s, 137 int fd, int64_t file_offset, unsigned int len, unsigned int block); 138 139/** 140 * sparse_file_write - write a sparse file to a file 141 * 142 * @s - sparse file cookie 143 * @fd - file descriptor to write to 144 * @gz - write a gzipped file 145 * @sparse - write in the Android sparse file format 146 * @crc - append a crc chunk 147 * 148 * Writes a sparse file to a file. If gz is true, the data will be passed 149 * through zlib. If sparse is true, the file will be written in the Android 150 * sparse file format. If sparse is false, the file will be written by seeking 151 * over unused chunks, producing a smaller file if the filesystem supports 152 * sparse files. If crc is true, the crc of the expanded data will be 153 * calculated and appended in a crc chunk. 154 * 155 * Returns 0 on success, negative errno on error. 156 */ 157int sparse_file_write(struct sparse_file *s, int fd, bool gz, bool sparse, 158 bool crc); 159 160#endif 161