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= (uint) *complen;
res= compress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet, (uLong) *len);
*complen= tmp_complen;
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;
}
/*
Change size of file.
SYNOPSIS
my_chsize()
fd File descriptor
new_length New file size
filler If we don't have truncate, fill up all bytes after
new_length with this character
MyFlags Flags
DESCRIPTION
my_chsize() truncates file if shorter else fill with the filler character.
The function also changes the file pointer. Usually it points to the end
of the file after execution.
RETURN VALUE
0 Ok
1 Error
*/
int my_chsize(File fd, my_off_t newlength, int filler, myf MyFlags)
{
my_off_t oldsize;
uchar buff[IO_SIZE];
DBUG_ENTER("my_chsize");
DBUG_PRINT("my",("fd: %d length: %lu MyFlags: %d",fd,(ulong) newlength,
MyFlags));
if ((oldsize= my_seek(fd, 0L, MY_SEEK_END, MYF(MY_WME+MY_FAE))) == newlength)
DBUG_RETURN(0);
DBUG_PRINT("info",("old_size: %ld", (ulong) oldsize));
if (oldsize > newlength)
{
#ifdef _WIN32
if (my_win_chsize(fd, newlength))
{
my_errno= errno;
goto err;
}
DBUG_RETURN(0);
#elif defined(HAVE_FTRUNCATE)
if (ftruncate(fd, (off_t) newlength))
{
my_errno= errno;
goto err;
}
DBUG_RETURN(0);
#elif defined(HAVE_CHSIZE)
if (chsize(fd, (off_t) newlength))
{
my_errno=errno;
goto err;
}
DBUG_RETURN(0);
#else
/*
Fill space between requested length and true length with 'filler'
We should never come here on any modern machine
*/
if (my_seek(fd, newlength, MY_SEEK_SET, MYF(MY_WME+MY_FAE))
== MY_FILEPOS_ERROR)
{
goto err;
}
swap_variables(my_off_t, newlength, oldsize);
#endif
}
/* Full file with 'filler' until it's as big as requested */
bfill(buff, IO_SIZE, filler);
while (newlength-oldsize > IO_SIZE)
{
if (my_write(fd, buff, IO_SIZE, MYF(MY_NABP)))
goto err;
oldsize+= IO_SIZE;
}
if (my_write(fd,buff,(size_t) (newlength-oldsize), MYF(MY_NABP)))
goto err;
DBUG_RETURN(0);
err:
DBUG_PRINT("error", ("errno: %d", errno));
if (MyFlags & MY_WME)
my_error(EE_CANT_CHSIZE, MYF(ME_BELL+ME_WAITTANG), my_errno);
DBUG_RETURN(1);
} /* my_chsize */
