mirror of
https://git.do.srb2.org/STJr/SRB2.git
synced 2024-11-22 04:21:23 +00:00
91 lines
4.5 KiB
C
91 lines
4.5 KiB
C
/* gzlog.h
|
|
Copyright (C) 2004, 2008, 2012 Mark Adler, all rights reserved
|
|
version 2.2, 14 Aug 2012
|
|
|
|
This software is provided 'as-is', without any express or implied
|
|
warranty. In no event will the author be held liable for any damages
|
|
arising from the use of this software.
|
|
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it
|
|
freely, subject to the following restrictions:
|
|
|
|
1. The origin of this software must not be misrepresented; you must not
|
|
claim that you wrote the original software. If you use this software
|
|
in a product, an acknowledgment in the product documentation would be
|
|
appreciated but is not required.
|
|
2. Altered source versions must be plainly marked as such, and must not be
|
|
misrepresented as being the original software.
|
|
3. This notice may not be removed or altered from any source distribution.
|
|
|
|
Mark Adler madler@alumni.caltech.edu
|
|
*/
|
|
|
|
/* Version History:
|
|
1.0 26 Nov 2004 First version
|
|
2.0 25 Apr 2008 Complete redesign for recovery of interrupted operations
|
|
Interface changed slightly in that now path is a prefix
|
|
Compression now occurs as needed during gzlog_write()
|
|
gzlog_write() now always leaves the log file as valid gzip
|
|
2.1 8 Jul 2012 Fix argument checks in gzlog_compress() and gzlog_write()
|
|
2.2 14 Aug 2012 Clean up signed comparisons
|
|
*/
|
|
|
|
/*
|
|
The gzlog object allows writing short messages to a gzipped log file,
|
|
opening the log file locked for small bursts, and then closing it. The log
|
|
object works by appending stored (uncompressed) data to the gzip file until
|
|
1 MB has been accumulated. At that time, the stored data is compressed, and
|
|
replaces the uncompressed data in the file. The log file is truncated to
|
|
its new size at that time. After each write operation, the log file is a
|
|
valid gzip file that can decompressed to recover what was written.
|
|
|
|
The gzlog operations can be interrupted at any point due to an application or
|
|
system crash, and the log file will be recovered the next time the log is
|
|
opened with gzlog_open().
|
|
*/
|
|
|
|
#ifndef GZLOG_H
|
|
#define GZLOG_H
|
|
|
|
/* gzlog object type */
|
|
typedef void gzlog;
|
|
|
|
/* Open a gzlog object, creating the log file if it does not exist. Return
|
|
NULL on error. Note that gzlog_open() could take a while to complete if it
|
|
has to wait to verify that a lock is stale (possibly for five minutes), or
|
|
if there is significant contention with other instantiations of this object
|
|
when locking the resource. path is the prefix of the file names created by
|
|
this object. If path is "foo", then the log file will be "foo.gz", and
|
|
other auxiliary files will be created and destroyed during the process:
|
|
"foo.dict" for a compression dictionary, "foo.temp" for a temporary (next)
|
|
dictionary, "foo.add" for data being added or compressed, "foo.lock" for the
|
|
lock file, and "foo.repairs" to log recovery operations performed due to
|
|
interrupted gzlog operations. A gzlog_open() followed by a gzlog_close()
|
|
will recover a previously interrupted operation, if any. */
|
|
gzlog *gzlog_open(char *path);
|
|
|
|
/* Write to a gzlog object. Return zero on success, -1 if there is a file i/o
|
|
error on any of the gzlog files (this should not happen if gzlog_open()
|
|
succeeded, unless the device has run out of space or leftover auxiliary
|
|
files have permissions or ownership that prevent their use), -2 if there is
|
|
a memory allocation failure, or -3 if the log argument is invalid (e.g. if
|
|
it was not created by gzlog_open()). This function will write data to the
|
|
file uncompressed, until 1 MB has been accumulated, at which time that data
|
|
will be compressed. The log file will be a valid gzip file upon successful
|
|
return. */
|
|
int gzlog_write(gzlog *log, void *data, size_t len);
|
|
|
|
/* Force compression of any uncompressed data in the log. This should be used
|
|
sparingly, if at all. The main application would be when a log file will
|
|
not be appended to again. If this is used to compress frequently while
|
|
appending, it will both significantly increase the execution time and
|
|
reduce the compression ratio. The return codes are the same as for
|
|
gzlog_write(). */
|
|
int gzlog_compress(gzlog *log);
|
|
|
|
/* Close a gzlog object. Return zero on success, -3 if the log argument is
|
|
invalid. The log object is freed, and so cannot be referenced again. */
|
|
int gzlog_close(gzlog *log);
|
|
|
|
#endif
|