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