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/* Copyright (C) 2000 MySQL AB
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Written by Sinisa Milivojevic <sinisa@mysql.com> */
#include <my_global.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,MYF(MY_WME));
}
DBUG_RETURN(0);
}
uchar *my_compress_alloc(const uchar *packet, size_t *len, size_t *complen)
{
uchar *compbuf;
uLongf tmp_complen;
int res;
*complen= *len * 120 / 100 + 12;
if (!(compbuf= (uchar *) my_malloc(*complen, MYF(MY_WME))))
return 0; /* Not enough memory */
tmp_complen= (uLongf) *complen;
res= compress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet, (uLong) *len);
*complen= tmp_complen;
if (res != Z_OK)
{
my_free(compbuf, MYF(MY_WME));
return 0;
}
if (*complen >= *len)
{
*complen= 0;
my_free(compbuf, MYF(MY_WME));
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 orignal 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(*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, MYF(MY_WME));
DBUG_RETURN(1);
}
memcpy(packet, compbuf, *complen);
my_free(compbuf, MYF(MY_WME));
}
else
*complen= len;
DBUG_RETURN(0);
}
/*
Internal representation of the frm blob is:
ver 4 bytes
orglen 4 bytes
complen 4 bytes
*/
#define BLOB_HEADER 12
/*
packfrm is a method used to compress the frm file for storage in a
handler. This method was developed for the NDB handler and has been moved
here to serve also other uses.
SYNOPSIS
packfrm()
data Data reference to frm file data.
len Length of frm file data
out:pack_data Reference to the pointer to the packed frm data
out:pack_len Length of packed frm file data
NOTES
data is replaced with compressed content
RETURN VALUES
0 Success
>0 Failure
*/
int packfrm(uchar *data, size_t len,
uchar **pack_data, size_t *pack_len)
{
int error;
size_t org_len, comp_len, blob_len;
uchar *blob;
DBUG_ENTER("packfrm");
DBUG_PRINT("enter", ("data: 0x%lx len: %lu", (long) data, (ulong) len));
error= 1;
org_len= len;
if (my_compress((uchar*)data, &org_len, &comp_len))
goto err;
DBUG_PRINT("info", ("org_len: %lu comp_len: %lu", (ulong) org_len,
(ulong) comp_len));
DBUG_DUMP("compressed", data, org_len);
error= 2;
blob_len= BLOB_HEADER + org_len;
if (!(blob= (uchar*) my_malloc(blob_len,MYF(MY_WME))))
goto err;
/* Store compressed blob in machine independent format */
int4store(blob, 1);
int4store(blob+4, (uint32) len);
int4store(blob+8, (uint32) org_len); /* compressed length */
/* Copy frm data into blob, already in machine independent format */
memcpy(blob+BLOB_HEADER, data, org_len);
*pack_data= blob;
*pack_len= blob_len;
error= 0;
DBUG_PRINT("exit", ("pack_data: 0x%lx pack_len: %lu",
(long) *pack_data, (ulong) *pack_len));
err:
DBUG_RETURN(error);
}
/*
unpackfrm is a method used to decompress the frm file received from a
handler. This method was developed for the NDB handler and has been moved
here to serve also other uses for other clustered storage engines.
SYNOPSIS
unpackfrm()
pack_data Data reference to packed frm file data
out:unpack_data Reference to the pointer to the unpacked frm data
out:unpack_len Length of unpacked frm file data
RETURN VALUES¨
0 Success
>0 Failure
*/
int unpackfrm(uchar **unpack_data, size_t *unpack_len,
const uchar *pack_data)
{
uchar *data;
size_t complen, orglen;
ulong ver;
DBUG_ENTER("unpackfrm");
DBUG_PRINT("enter", ("pack_data: 0x%lx", (long) pack_data));
ver= uint4korr(pack_data);
orglen= uint4korr(pack_data+4);
complen= uint4korr(pack_data+8);
DBUG_PRINT("blob",("ver: %lu complen: %lu orglen: %lu",
ver, (ulong) complen, (ulong) orglen));
DBUG_DUMP("blob->data", pack_data + BLOB_HEADER, complen);
if (ver != 1)
DBUG_RETURN(1);
if (!(data= my_malloc(max(orglen, complen), MYF(MY_WME))))
DBUG_RETURN(2);
memcpy(data, pack_data + BLOB_HEADER, complen);
if (my_uncompress(data, complen, &orglen))
{
my_free(data, MYF(0));
DBUG_RETURN(3);
}
*unpack_data= data;
*unpack_len= orglen;
DBUG_PRINT("exit", ("frmdata: 0x%lx len: %lu", (long) *unpack_data,
(ulong) *unpack_len));
DBUG_RETURN(0);
}
#endif /* HAVE_COMPRESS */
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