| .\" Copyright (c) 2003-2011 Tim Kientzle |
| .\" All rights reserved. |
| .\" |
| .\" Redistribution and use in source and binary forms, with or without |
| .\" modification, are permitted provided that the following conditions |
| .\" are met: |
| .\" 1. Redistributions of source code must retain the above copyright |
| .\" notice, this list of conditions and the following disclaimer. |
| .\" 2. Redistributions in binary form must reproduce the above copyright |
| .\" notice, this list of conditions and the following disclaimer in the |
| .\" documentation and/or other materials provided with the distribution. |
| .\" |
| .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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| .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| .\" $FreeBSD$ |
| .\" |
| .Dd February 2, 2012 |
| .Dt ARCHIVE_READ_DATA 3 |
| .Os |
| .Sh NAME |
| .Nm archive_read_data |
| .Nm archive_read_data_block , |
| .Nm archive_read_data_skip , |
| .Nm archive_read_data_into_fd |
| .Nd functions for reading streaming archives |
| .Sh LIBRARY |
| Streaming Archive Library (libarchive, -larchive) |
| .Sh SYNOPSIS |
| .In archive.h |
| .Ft ssize_t |
| .Fn archive_read_data "struct archive *" "void *buff" "size_t len" |
| .Ft int |
| .Fo archive_read_data_block |
| .Fa "struct archive *" |
| .Fa "const void **buff" |
| .Fa "size_t *len" |
| .Fa "off_t *offset" |
| .Fc |
| .Ft int |
| .Fn archive_read_data_skip "struct archive *" |
| .Ft int |
| .Fn archive_read_data_into_fd "struct archive *" "int fd" |
| .\" |
| .Sh DESCRIPTION |
| .Bl -tag -compact -width indent |
| .It Fn archive_read_data |
| Read data associated with the header just read. |
| Internally, this is a convenience function that calls |
| .Fn archive_read_data_block |
| and fills any gaps with nulls so that callers see a single |
| continuous stream of data. |
| .It Fn archive_read_data_block |
| Return the next available block of data for this entry. |
| Unlike |
| .Fn archive_read_data , |
| the |
| .Fn 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. |
| .It Fn archive_read_data_skip |
| A convenience function that repeatedly calls |
| .Fn archive_read_data_block |
| to skip all of the data for this archive entry. |
| Note that this function is invoked automatically by |
| .Fn archive_read_next_header2 |
| if the previous entry was not completely consumed. |
| .It Fn archive_read_data_into_fd |
| A convenience function that repeatedly calls |
| .Fn archive_read_data_block |
| to copy the entire entry to the provided file descriptor. |
| .El |
| .\" |
| .Sh RETURN VALUES |
| Most functions return zero on success, non-zero on error. |
| The possible return codes include: |
| .Cm ARCHIVE_OK |
| (the operation succeeded), |
| .Cm ARCHIVE_WARN |
| (the operation succeeded but a non-critical error was encountered), |
| .Cm ARCHIVE_EOF |
| (end-of-archive was encountered), |
| .Cm ARCHIVE_RETRY |
| (the operation failed but can be retried), |
| and |
| .Cm ARCHIVE_FATAL |
| (there was a fatal error; the archive should be closed immediately). |
| .Pp |
| .Fn archive_read_data |
| returns a count of bytes actually read or zero at the end of the entry. |
| On error, a value of |
| .Cm ARCHIVE_FATAL , |
| .Cm ARCHIVE_WARN , |
| or |
| .Cm ARCHIVE_RETRY |
| is returned. |
| .\" |
| .Sh ERRORS |
| Detailed error codes and textual descriptions are available from the |
| .Fn archive_errno |
| and |
| .Fn archive_error_string |
| functions. |
| .\" |
| .Sh SEE ALSO |
| .Xr tar 1 , |
| .Xr libarchive 3 , |
| .Xr archive_read 3 , |
| .Xr archive_read_extract 3 , |
| .Xr archive_read_filter 3 , |
| .Xr archive_read_format 3 , |
| .Xr archive_read_header 3 , |
| .Xr archive_read_open 3 , |
| .Xr archive_read_set_options 3 , |
| .Xr archive_util 3 , |
| .Xr tar 5 |