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diff --git a/Utilities/cmlibarchive/libarchive/archive_read.3 b/Utilities/cmlibarchive/libarchive/archive_read.3 new file mode 100644 index 000000000..52851925c --- /dev/null +++ b/Utilities/cmlibarchive/libarchive/archive_read.3 @@ -0,0 +1,250 @@ +.\" Copyright (c) 2003-2007 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 +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" 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 +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD: head/lib/libarchive/archive_read.3 191595 2009-04-27 20:13:13Z kientzle $ +.\" +.Dd March 23, 2011 +.Dt ARCHIVE_READ 3 +.Os +.Sh NAME +.Nm archive_read +.Nd functions for reading streaming archives +.Sh SYNOPSIS +.In archive.h +.Sh DESCRIPTION +These functions provide a complete API for reading streaming archives. +The general process is to first create the +.Tn struct archive +object, set options, initialize the reader, iterate over the archive +headers and associated data, then close the archive and release all +resources. +.\" +.Ss Create archive object +See +.Xr archive_read_new 3 . +.Pp +To read an archive, you must first obtain an initialized +.Tn struct archive +object from +.Fn archive_read_new . +.\" +.Ss Enable filters and formats +See +.Xr archive_read_filter 3 +and +.Xr archive_read_format 3 . +.Pp +You can then modify this object for the desired operations with the +various +.Fn archive_read_set_XXX +and +.Fn archive_read_support_XXX +functions. +In particular, you will need to invoke appropriate +.Fn archive_read_support_XXX +functions to enable the corresponding compression and format +support. +Note that these latter functions perform two distinct operations: +they cause the corresponding support code to be linked into your +program, and they enable the corresponding auto-detect code. +Unless you have specific constraints, you will generally want +to invoke +.Fn archive_read_support_filter_all +and +.Fn archive_read_support_format_all +to enable auto-detect for all formats and compression types +currently supported by the library. +.\" +.Ss Set options +See +.Xr archive_read_set_options 3 . +.\" +.Ss Open archive +See +.Xr archive_read_open 3 . +.Pp +Once you have prepared the +.Tn struct archive +object, you call +.Fn archive_read_open +to actually open the archive and prepare it for reading. +There are several variants of this function; +the most basic expects you to provide pointers to several +functions that can provide blocks of bytes from the archive. +There are convenience forms that allow you to +specify a filename, file descriptor, +.Ft "FILE *" +object, or a block of memory from which to read the archive data. +Note that the core library makes no assumptions about the +size of the blocks read; +callback functions are free to read whatever block size is +most appropriate for the medium. +.\" +.Ss Consume archive +See +.Xr archive_read_header 3 , +.Xr archive_read_data 3 +and +.Xr archive_read_extract 3 . +.Pp +Each archive entry consists of a header followed by a certain +amount of data. +You can obtain the next header with +.Fn archive_read_next_header , +which returns a pointer to an +.Tn struct archive_entry +structure with information about the current archive element. +If the entry is a regular file, then the header will be followed +by the file data. +You can use +.Fn archive_read_data +(which works much like the +.Xr read 2 +system call) +to read this data from the archive, or +.Fn archive_read_data_block +which provides a slightly more efficient interface. +You may prefer to use the higher-level +.Fn archive_read_data_skip , +which reads and discards the data for this entry, +.Fn archive_read_data_to_file , +which copies the data to the provided file descriptor, or +.Fn archive_read_extract , +which recreates the specified entry on disk and copies data +from the archive. +In particular, note that +.Fn archive_read_extract +uses the +.Tn struct archive_entry +structure that you provide it, which may differ from the +entry just read from the archive. +In particular, many applications will want to override the +pathname, file permissions, or ownership. +.\" +.Ss Release resources +See +.Xr archive_read_free 3 . +.Pp +Once you have finished reading data from the archive, you +should call +.Fn archive_read_close +to close the archive, then call +.Fn archive_read_free +to release all resources, including all memory allocated by the library. +.\" +.Sh EXAMPLE +The following illustrates basic usage of the library. +In this example, +the callback functions are simply wrappers around the standard +.Xr open 2 , +.Xr read 2 , +and +.Xr close 2 +system calls. +.Bd -literal -offset indent +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_filter_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\en",archive_entry_pathname(entry)); + archive_read_data_skip(a); + } + archive_read_free(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); +} +.Ed +.\" .Sh ERRORS +.Sh SEE ALSO +.Xr tar 1 , +.Xr libarchive 3 , +.Xr archive_read_new 3 , +.Xr archive_read_data 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 +.Sh HISTORY +The +.Nm libarchive +library first appeared in +.Fx 5.3 . +.Sh AUTHORS +.An -nosplit +The +.Nm libarchive +library was written by +.An Tim Kientzle Aq kientzle@acm.org . +.Sh BUGS +Many traditional archiver programs treat +empty files as valid empty archives. +For example, many implementations of +.Xr tar 1 +allow you to append entries to an empty file. +Of course, it is impossible to determine the format of an empty file +by inspecting the contents, so this library treats empty files as +having a special +.Dq empty +format. |