1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
Copyright (c) 2022, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
/* Written by Sinisa Milivojevic <sinisa@mysql.com> */
#include <mysys_priv.h>
#ifdef HAVE_COMPRESS
#include <my_sys.h>
#ifndef SCO
#include <m_string.h>
#endif
#include <zlib.h>
/*
This replaces the packet with a compressed packet
SYNOPSIS
my_compress()
packet Data to compress. This is is replaced with the compressed data.
len Length of data to compress at 'packet'
complen out: 0 if packet was not compressed
RETURN
1 error. 'len' is not changed'
0 ok. In this case 'len' contains the size of the compressed packet
*/
my_bool my_compress(uchar *packet, size_t *len, size_t *complen)
{
DBUG_ENTER("my_compress");
if (*len < MIN_COMPRESS_LENGTH)
{
*complen=0;
DBUG_PRINT("note",("Packet too short: Not compressed"));
}
else
{
uchar *compbuf=my_compress_alloc(packet,len,complen);
if (!compbuf)
DBUG_RETURN(*complen ? 0 : 1);
memcpy(packet,compbuf,*len);
my_free(compbuf);
}
DBUG_RETURN(0);
}
void *my_az_allocator(void *dummy __attribute__((unused)), unsigned int items,
unsigned int size)
{
return my_malloc(key_memory_my_compress_alloc, (size_t)items*(size_t)size,
MYF(0));
}
void my_az_free(void *dummy __attribute__((unused)), void *address)
{
my_free(address);
}
/*
This works like zlib compress(), but using custom memory allocators to work
better with my_malloc leak detection and Valgrind.
*/
int my_compress_buffer(uchar *dest, size_t *destLen,
const uchar *source, size_t sourceLen)
{
z_stream stream;
int err;
stream.next_in = (Bytef*)source;
stream.avail_in = (uInt)sourceLen;
stream.next_out = (Bytef*)dest;
stream.avail_out = (uInt)*destLen;
if ((size_t)stream.avail_out != *destLen)
return Z_BUF_ERROR;
stream.zalloc = (alloc_func)my_az_allocator;
stream.zfree = (free_func)my_az_free;
stream.opaque = (voidpf)0;
err = deflateInit(&stream, Z_DEFAULT_COMPRESSION);
if (err != Z_OK) return err;
err = deflate(&stream, Z_FINISH);
if (err != Z_STREAM_END) {
deflateEnd(&stream);
return err == Z_OK ? Z_BUF_ERROR : err;
}
*destLen = stream.total_out;
err = deflateEnd(&stream);
return err;
}
uchar *my_compress_alloc(const uchar *packet, size_t *len, size_t *complen)
{
uchar *compbuf;
int res;
*complen= *len * 120 / 100 + 12;
if (!(compbuf= (uchar *) my_malloc(key_memory_my_compress_alloc,
*complen, MYF(MY_WME))))
return 0;
res= my_compress_buffer(compbuf, complen, packet, *len);
if (res != Z_OK)
{
my_free(compbuf);
return 0;
}
if (*complen >= *len)
{
*complen= 0;
my_free(compbuf);
DBUG_PRINT("note",("Packet got longer on compression; Not compressed"));
return 0;
}
/* Store length of compressed packet in *len */
swap_variables(size_t, *len, *complen);
return compbuf;
}
/*
Uncompress packet
SYNOPSIS
my_uncompress()
packet Compressed data. This is is replaced with the original data.
len Length of compressed data
complen Length of the packet buffer (must be enough for the original
data)
RETURN
1 error
0 ok. In this case 'complen' contains the updated size of the
real data.
*/
my_bool my_uncompress(uchar *packet, size_t len, size_t *complen)
{
uLongf tmp_complen;
DBUG_ENTER("my_uncompress");
if (*complen) /* If compressed */
{
uchar *compbuf= (uchar *) my_malloc(key_memory_my_compress_alloc,
*complen,MYF(MY_WME));
int error;
if (!compbuf)
DBUG_RETURN(1); /* Not enough memory */
tmp_complen= (uLongf) *complen;
error= uncompress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet,
(uLong) len);
*complen= tmp_complen;
if (error != Z_OK)
{ /* Probably wrong packet */
DBUG_PRINT("error",("Can't uncompress packet, error: %d",error));
my_free(compbuf);
DBUG_RETURN(1);
}
memcpy(packet, compbuf, *complen);
my_free(compbuf);
}
else
*complen= len;
DBUG_RETURN(0);
}
#endif /* HAVE_COMPRESS */
|
