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-/* 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 interupted 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