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NAME

archive_read_new

 
archive_read_support_compression_all

 
archive_read_support_compression_bzip2

 
archive_read_support_compression_compress

 
archive_read_support_compression_gzip

 
archive_read_support_compression_none

 
archive_read_support_compression_program

 
archive_read_support_format_all

 
archive_read_support_format_cpio

 
archive_read_support_format_empty

 
archive_read_support_format_iso9660

 
archive_read_support_format_tar

 
archive_read_support_format_zip

 
archive_read_open

 
archive_read_open2

 
archive_read_open_fd

 
archive_read_open_FILE

 
archive_read_open_filename

 
archive_read_open_memory

 
archive_read_next_header

 
archive_read_data

 
archive_read_data_block

 
archive_read_data_skip

 

archive_read_data_into_buffer

 

archive_read_data_into_fd

 
archive_read_extract

 
archive_read_extract2

 
archive_read_extract_set_progress_callback

 
archive_read_close

 
archive_read_finish

 - functions for reading streaming archives

 

SYNOPSIS

DESCRIPTION

Fn archive_read_new

Allocates and initializes a struct archive object suitable for reading from an archive.

archive_read_support_compression_all (,);
archive_read_support_compression_bzip2 (,);
archive_read_support_compression_compress (,);
archive_read_support_compression_gzip (,);
archive_read_support_compression_none ();

Enables auto-detection code and decompression support for the specified compression. Note that ``none'' is always enabled by default. For convenience, archive_read_support_compression_all ();
enables all available decompression code.

Fn archive_read_support_compression_program

Data is fed through the specified external program before being dearchived. Note that this disables automatic detection of the compression format, so it makes no sense to specify this in conjunction with any other decompression option.

archive_read_support_format_all (,);
archive_read_support_format_cpio (,);
archive_read_support_format_empty (,);
archive_read_support_format_iso9660 (,);
archive_read_support_format_tar (,);
archive_read_support_format_zip ();

Enables support---including auto-detection code---for the specified archive format. For example, archive_read_support_format_tar ();
enables support for a variety of standard tar formats, old-style tar, ustar, pax interchange format, and many common variants. For convenience, archive_read_support_format_all ();
enables support for all available formats. Only empty archives are supported by default.

Fn archive_read_open

The same as archive_read_open2 (,);
except that the skip callback is assumed to be NULL

Fn archive_read_open2

Freeze the settings, open the archive, and prepare for reading entries. This is the most generic version of this call, which accepts four callback functions. Most clients will want to use archive_read_open_filename (,);
archive_read_open_FILE (,);
archive_read_open_fd (,);
or archive_read_open_memory ();
instead. The library invokes the client-provided functions to obtain raw bytes from the archive.

Fn archive_read_open_FILE

Like archive_read_open (,);
except that it accepts a FILE * pointer. This function should not be used with tape drives or other devices that require strict I/O blocking.

Fn archive_read_open_fd

Like archive_read_open (,);
except that it accepts a file descriptor and block size rather than a set of function pointers. Note that the file descriptor will not be automatically closed at end-of-archive. This function is safe for use with tape drives or other blocked devices.

Fn archive_read_open_file

This is a deprecated synonym for archive_read_open_filename (.);

Fn archive_read_open_filename

Like archive_read_open (,);
except that it accepts a simple filename and a block size. A NULL filename represents standard input. This function is safe for use with tape drives or other blocked devices.

Fn archive_read_open_memory

Like archive_read_open (,);
except that it accepts a pointer and size of a block of memory containing the archive data.

Fn archive_read_next_header

Read the header for the next entry and return a pointer to a struct archive_entry

Fn archive_read_data

Read data associated with the header just read. Internally, this is a convenience function that calls archive_read_data_block ();
and fills any gaps with nulls so that callers see a single continuous stream of data.

Fn archive_read_data_block

Return the next available block of data for this entry. Unlike archive_read_data (,);
the archive_read_data_block ();
function avoids copying data and allows you to correctly handle sparse files, as supported by some archive formats. The library guarantees that offsets will increase and that blocks will not overlap. Note that the blocks returned from this function can be much larger than the block size read from disk, due to compression and internal buffer optimizations.

Fn archive_read_data_skip

A convenience function that repeatedly calls archive_read_data_block ();
to skip all of the data for this archive entry.

Fn archive_read_data_into_buffer

This function is deprecated and will be removed. Use archive_read_data ();
instead.

Fn archive_read_data_into_fd

A convenience function that repeatedly calls archive_read_data_block ();
to copy the entire entry to the provided file descriptor.

Fn archive_read_extract , Fn archive_read_extract_set_skip_file

A convenience function that wraps the corresponding archive_write_disk3 interfaces. The first call to archive_read_extract ();
creates a restore object using archive_write_disk_new3 and archive_write_disk_set_standard_lookup3, then transparently invokes archive_write_disk_set_options3, archive_write_header3, archive_write_data3, and archive_write_finish_entry3 to create the entry on disk and copy data into it. The flags argument is passed unmodified to archive_write_disk_set_options3.

Fn archive_read_extract2

This is another version of archive_read_extract ();
that allows you to provide your own restore object. In particular, this allows you to override the standard lookup functions using archive_write_disk_set_group_lookup3, and archive_write_disk_set_user_lookup3. Note that archive_read_extract2 ();
does not accept a flags argument; you should use archive_write_disk_set_options ();
to set the restore options yourself.

Fn archive_read_extract_set_progress_callback

Sets a pointer to a user-defined callback that can be used for updating progress displays during extraction. The progress function will be invoked during the extraction of large regular files. The progress function will be invoked with the pointer provided to this call. Generally, the data pointed to should include a reference to the archive object and the archive_entry object so that various statistics can be retrieved for the progress display.

Fn archive_read_close

Complete the archive and invoke the close callback.

Fn archive_read_finish

Invokes archive_read_close ();
if it was not invoked manually, then release all resources. Note: In libarchive 1.x, this function was declared to return void , which made it impossible to detect certain errors when archive_read_close ();
was invoked implicitly from this function. The declaration is corrected beginning with libarchive 2.0.

Note that the library determines most of the relevant information about the archive by inspection. In particular, it automatically detects gzip(1) or bzip2(1) compression and transparently performs the appropriate decompression. It also automatically detects the archive format.

A complete description of the struct archive and struct archive_entry objects can be found in the overview manual page for libarchive(3).  

CLIENT CALLBACKS

Ft typedef ssize_t

Fo archive_read_callback Fa struct archive * Fa void *client_data Fa const void **buffer Fc

typedef int Fo archive_skip_callback Fa struct archive * Fa void *client_data Fa size_t request Fc

Ft typedef int

archive_open_callback (struct archive * void *client_data);

Ft typedef int

archive_close_callback (struct archive * void *client_data);

The open callback is invoked by archive_open (.);
It should return ARCHIVE_OK if the underlying file or data source is successfully opened. If the open fails, it should call archive_set_error ();
to register an error code and message and return ARCHIVE_FATAL

The read callback is invoked whenever the library requires raw bytes from the archive. The read callback should read data into a buffer, set the const void **buffer argument to point to the available data, and return a count of the number of bytes available. The library will invoke the read callback again only after it has consumed this data. The library imposes no constraints on the size of the data blocks returned. On end-of-file, the read callback should return zero. On error, the read callback should invoke archive_set_error ();
to register an error code and message and return -1.

The skip callback is invoked when the library wants to ignore a block of data. The return value is the number of bytes actually skipped, which may differ from the request. If the callback cannot skip data, it should return zero. If the skip callback is not provided (the function pointer is NULL ), the library will invoke the read function instead and simply discard the result. A skip callback can provide significant performance gains when reading uncompressed archives from slow disk drives or other media that can skip quickly.

The close callback is invoked by archive_close when the archive processing is complete. The callback should return ARCHIVE_OK on success. On failure, the callback should invoke archive_set_error ();
to register an error code and message and return ARCHIVE_FATAL.  

EXAMPLE

void
list_archive(const char *name)
{
  struct mydata *mydata;
  struct archive *a;
  struct archive_entry *entry;

  mydata = malloc(sizeof(struct mydata));
  a = archive_read_new();
  mydata->name = name;
  archive_read_support_compression_all(a);
  archive_read_support_format_all(a);
  archive_read_open(a, mydata, myopen, myread, myclose);
  while (archive_read_next_header(a, &entry) == ARCHIVE_OK) {
    printf("%s\n",archive_entry_pathname(entry));
    archive_read_data_skip(a);
  }
  archive_read_finish(a);
  free(mydata);
}

ssize_t
myread(struct archive *a, void *client_data, const void **buff)
{
  struct mydata *mydata = client_data;

  *buff = mydata->buff;
  return (read(mydata->fd, mydata->buff, 10240));
}

int
myopen(struct archive *a, void *client_data)
{
  struct mydata *mydata = client_data;

  mydata->fd = open(mydata->name, O_RDONLY);
  return (mydata->fd >= 0 ? ARCHIVE_OK : ARCHIVE_FATAL);
}

int
myclose(struct archive *a, void *client_data)
{
  struct mydata *mydata = client_data;

  if (mydata->fd > 0)
    close(mydata->fd);
  return (ARCHIVE_OK);
}

RETURN VALUES

archive_read_new ();
returns a pointer to a freshly allocated struct archive object. It returns NULL on error.

archive_read_data ();
returns a count of bytes actually read or zero at the end of the entry. On error, a value of ARCHIVE_FATAL ARCHIVE_WARN or ARCHIVE_RETRY is returned and an error code and textual description can be retrieved from the archive_errno ();
and archive_error_string ();
functions.

The library expects the client callbacks to behave similarly. If there is an error, you can use archive_set_error ();
to set an appropriate error code and description, then return one of the non-zero values above. (Note that the value eventually returned to the client may not be the same; many errors that are not critical at the level of basic I/O can prevent the archive from being properly read, thus most I/O errors eventually cause ARCHIVE_FATAL to be returned.)  

SEE ALSO

HISTORY

AUTHORS

BUGS

Index

NAME

SYNOPSIS

DESCRIPTION

CLIENT CALLBACKS

EXAMPLE

RETURN VALUES

SEE ALSO

HISTORY

AUTHORS

BUGS

Партнёры:

Хостинг: