1/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
3#ident "$Id$"
4/*======
5This file is part of PerconaFT.
6
7
8Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.
9
10 PerconaFT is free software: you can redistribute it and/or modify
11 it under the terms of the GNU General Public License, version 2,
12 as published by the Free Software Foundation.
13
14 PerconaFT is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
21
22----------------------------------------
23
24 PerconaFT is free software: you can redistribute it and/or modify
25 it under the terms of the GNU Affero General Public License, version 3,
26 as published by the Free Software Foundation.
27
28 PerconaFT is distributed in the hope that it will be useful,
29 but WITHOUT ANY WARRANTY; without even the implied warranty of
30 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
31 GNU Affero General Public License for more details.
32
33 You should have received a copy of the GNU Affero General Public License
34 along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
35======= */
36
37#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."
38
39#pragma once
40
41#include <zlib.h>
42#include <db.h>
43
44// The following provides an abstraction of quicklz and zlib.
45// We offer three compression methods: ZLIB, QUICKLZ, and LZMA, as well as a "no compression" option. These options are declared in make_tdb.c.
46// The resulting byte string includes enough information for us to decompress it. That is, we can tell whether it's z-compressed or qz-compressed or xz-compressed.
47
48size_t toku_compress_bound (enum toku_compression_method a, size_t size);
49// Effect: Return the number of bytes needed to compress a buffer of size SIZE using compression method A.
50// Typically, the result is a little bit larger than SIZE, since some data cannot be compressed.
51// Usage note: It may help to know roughly how much space is involved.
52// zlib's bound is something like (size + (size>>12) + (size>>14) + (size>>25) + 13.
53// quicklz's bound is something like size+400.
54
55void toku_compress (enum toku_compression_method a,
56 // the following types and naming conventions come from zlib.h
57 Bytef *dest, uLongf *destLen,
58 const Bytef *source, uLong sourceLen);
59// Effect: Using compression method A, compress SOURCE into DEST. The number of bytes to compress is passed in SOURCELEN.
60// On input: *destLen is the size of the buffer.
61// On output: *destLen is the size of the actual compressed data.
62// Usage note: sourceLen may be be zero (unlike for quicklz, which requires sourceLen>0).
63// Requires: The buffer must be big enough to hold the compressed data. (That is *destLen >= compressBound(a, sourceLen))
64// Requires: sourceLen < 2^32.
65// Usage note: Although we *try* to assert if the DESTLEN isn't big enough, it's possible that it's too late by then (in the case of quicklz which offers
66// no way to avoid a buffer overrun.) So we require that that DESTLEN is big enough.
67// Rationale: zlib's argument order is DEST then SOURCE with the size of the buffer passed in *destLen, and the size of the result returned in *destLen.
68// quicklz's argument order is SOURCE then DEST with the size returned (and it has no way to verify that an overright didn't happen).
69// We use zlib's calling conventions partly because it is safer, and partly because it is more established.
70// We also use zlib's ugly camel case convention for destLen and sourceLen.
71// Unlike zlib, we return no error codes. Instead, we require that the data be OK and the size of the buffers is OK, and assert if there's a problem.
72
73void toku_decompress (Bytef *dest, uLongf destLen,
74 const Bytef *source, uLongf sourceLen);
75// Effect: Decompress source (length sourceLen) into dest (length destLen)
76// This function can decompress data compressed with either zlib or quicklz compression methods (calling toku_compress(), which puts an appropriate header on so we know which it is.)
77// Requires: destLen is equal to the actual decompressed size of the data.
78// Requires: The source must have been properly compressed.
79