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/* Copyright (c) 2000-2003, 2007 MySQL AB
Use is subject to license terms
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 Street, Fifth Floor, Boston, MA 02110-1335 USA */
#include <my_global.h>
#include <mysql_com.h>
#include <mysql.h>
/* Get the length of next field. Change parameter to point at fieldstart */
ulong net_field_length(uchar **packet)
{
reg1 uchar *pos= (uchar *)*packet;
if (*pos < 251)
{
(*packet)++;
return (ulong) *pos;
}
if (*pos == 251)
{
(*packet)++;
return NULL_LENGTH;
}
if (*pos == 252)
{
(*packet)+=3;
return (ulong) uint2korr(pos+1);
}
if (*pos == 253)
{
(*packet)+=4;
return (ulong) uint3korr(pos+1);
}
(*packet)+=9; /* Must be 254 when here */
return (ulong) uint4korr(pos+1);
}
/* The same as above but returns longlong */
my_ulonglong net_field_length_ll(uchar **packet)
{
uchar *pos= *packet;
if (*pos < 251)
{
(*packet)++;
return (my_ulonglong) *pos;
}
if (*pos == 251)
{
(*packet)++;
return (my_ulonglong) NULL_LENGTH;
}
if (*pos == 252)
{
(*packet)+=3;
return (my_ulonglong) uint2korr(pos+1);
}
if (*pos == 253)
{
(*packet)+=4;
return (my_ulonglong) uint3korr(pos+1);
}
DBUG_ASSERT(*pos == 254);
(*packet)+=9; /* Must be 254 when here */
return (my_ulonglong) uint8korr(pos+1);
}
my_ulonglong safe_net_field_length_ll(uchar **packet, size_t packet_len)
{
uchar *pos= *packet;
if (packet_len < 1)
goto err;
if (*pos < 251)
{
(*packet)++;
return (my_ulonglong) *pos;
}
if (*pos == 251)
{
(*packet)++;
return (my_ulonglong) NULL_LENGTH;
}
if (*pos == 252)
{
if (packet_len < 3)
goto err;
(*packet)+=3;
return (my_ulonglong) uint2korr(pos+1);
}
if (*pos == 253)
{
if (packet_len < 4)
goto err;
(*packet)+=4;
return (my_ulonglong) uint3korr(pos+1);
}
if (packet_len < 9 || *pos != 254)
goto err;
(*packet)+=9;
return (my_ulonglong) uint8korr(pos+1);
err:
*packet = NULL;
return 0;
}
/*
Store an integer with simple packing into a output package
SYNOPSIS
net_store_length()
packet Store the packed integer here
length integers to store
NOTES
This is mostly used to store lengths of strings.
RETURN
Position in 'packet' after the packed length
*/
uchar *net_store_length(uchar *packet, ulonglong length)
{
if (length < 251)
{
*packet= (uchar) length;
return packet+1;
}
/* 251 is reserved for NULL */
if (length < 65536)
{
*packet++=252;
int2store(packet, (uint) length);
return packet+2;
}
if (length < 16777216)
{
*packet++=253;
int3store(packet, (ulong) length);
return packet+3;
}
*packet++=254;
int8store(packet,length);
return packet+8;
}
uchar *safe_net_store_length(uchar *packet, size_t packet_len, ulonglong length)
{
if (length < 251)
{
if (packet_len < 1)
return NULL;
*packet= (uchar) length;
return packet+1;
}
/* 251 is reserved for NULL */
if (length < 65536)
{
if (packet_len < 3)
return NULL;
*packet++=252;
int2store(packet, (uint) length);
return packet+2;
}
if (length < 16777216)
{
if (packet_len < 4)
return NULL;
*packet++=253;
int3store(packet, (ulong) length);
return packet+3;
}
if (packet_len < 9)
return NULL;
*packet++=254;
int8store(packet,length);
return packet+8;
}
/**
The length of space required to store the resulting length-encoded integer
for the given number. This function can be used at places where one needs to
dynamically allocate the buffer for a given number to be stored as length-
encoded integer.
@param num [IN] the input number
@return length of buffer needed to store this number [1, 3, 4, 9].
*/
uint net_length_size(ulonglong num)
{
if (num < (ulonglong) 251LL)
return 1;
if (num < (ulonglong) 65536LL)
return 3;
if (num < (ulonglong) 16777216LL)
return 4;
return 9;
}
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