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mariadb/mysys/my_compress.c
monty@mysql.com/narttu.mysql.fi 088e2395f1 WL#3817: Simplify string / memory area types and make things more consistent (first part) 
The following type conversions was done:

- Changed byte to uchar
- Changed gptr to uchar*
- Change my_string to char *
- Change my_size_t to size_t
- Change size_s to size_t

Removed declaration of byte, gptr, my_string, my_size_t and size_s. 

Following function parameter changes was done:
- All string functions in mysys/strings was changed to use size_t
  instead of uint for string lengths.
- All read()/write() functions changed to use size_t (including vio).
- All protocoll functions changed to use size_t instead of uint
- Functions that used a pointer to a string length was changed to use size_t*
- Changed malloc(), free() and related functions from using gptr to use void *
  as this requires fewer casts in the code and is more in line with how the
  standard functions work.
- Added extra length argument to dirname_part() to return the length of the
  created string.
- Changed (at least) following functions to take uchar* as argument:
  - db_dump()
  - my_net_write()
  - net_write_command()
  - net_store_data()
  - DBUG_DUMP()
  - decimal2bin() & bin2decimal()
- Changed my_compress() and my_uncompress() to use size_t. Changed one
  argument to my_uncompress() from a pointer to a value as we only return
  one value (makes function easier to use).
- Changed type of 'pack_data' argument to packfrm() to avoid casts.
- Changed in readfrm() and writefrom(), ha_discover and handler::discover()
  the type for argument 'frmdata' to uchar** to avoid casts.
- Changed most Field functions to use uchar* instead of char* (reduced a lot of
  casts).
- Changed field->val_xxx(xxx, new_ptr) to take const pointers.

Other changes:
- Removed a lot of not needed casts
- Added a few new cast required by other changes
- Added some cast to my_multi_malloc() arguments for safety (as string lengths
  needs to be uint, not size_t).
- Fixed all calls to hash-get-key functions to use size_t*. (Needed to be done
  explicitely as this conflict was often hided by casting the function to
  hash_get_key).
- Changed some buffers to memory regions to uchar* to avoid casts.
- Changed some string lengths from uint to size_t.
- Changed field->ptr to be uchar* instead of char*. This allowed us to
  get rid of a lot of casts.
- Some changes from true -> TRUE, false -> FALSE, unsigned char -> uchar
- Include zlib.h in some files as we needed declaration of crc32()
- Changed MY_FILE_ERROR to be (size_t) -1.
- Changed many variables to hold the result of my_read() / my_write() to be
  size_t. This was needed to properly detect errors (which are
  returned as (size_t) -1).
- Removed some very old VMS code
- Changed packfrm()/unpackfrm() to not be depending on uint size
  (portability fix)
- Removed windows specific code to restore cursor position as this
  causes slowdown on windows and we should not mix read() and pread()
  calls anyway as this is not thread safe. Updated function comment to
  reflect this. Changed function that depended on original behavior of
  my_pwrite() to itself restore the cursor position (one such case).
- Added some missing checking of return value of malloc().
- Changed definition of MOD_PAD_CHAR_TO_FULL_LENGTH to avoid 'long' overflow.
- Changed type of table_def::m_size from my_size_t to ulong to reflect that
  m_size is the number of elements in the array, not a string/memory
  length.
- Moved THD::max_row_length() to table.cc (as it's not depending on THD).
  Inlined max_row_length_blob() into this function.
- More function comments
- Fixed some compiler warnings when compiled without partitions.
- Removed setting of LEX_STRING() arguments in declaration (portability fix).
- Some trivial indentation/variable name changes.
- Some trivial code simplifications:
  - Replaced some calls to alloc_root + memcpy to use
    strmake_root()/strdup_root().
  - Changed some calls from memdup() to strmake() (Safety fix)
  - Simpler loops in client-simple.c
2007-05-10 12:59:39 +03:00

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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= *complen;
res= compress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet, *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= *complen;
error= uncompress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet,
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
RETURN VALUES
0 Success
>0 Failure
*/
int packfrm(const 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", org_len, comp_len));
DBUG_DUMP("compressed", (char*)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, complen, 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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