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/*
** Zabbix
** Copyright (C) 2001-2021 Zabbix SIA
**
** 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; either version 2 of the License, or
** (at your option) any later version.
**
** 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 02110-1301, USA.
**/
#include "common.h"
#include "zbxalgo.h"
/******************************************************************************
* *
* Function: zbx_serialize_uint31_compact *
* *
* Purpose: serialize 31 bit unsigned integer into utf-8 like byte stream *
* *
* Parameters: ptr - [OUT] the output buffer *
* value - [IN] the value to serialize *
* *
* Return value: The number of bytes written to the buffer. *
* *
* Comments: This serialization method should be used with variables usually *
* having small value while still supporting larger values. *
* *
******************************************************************************/
zbx_uint32_t zbx_serialize_uint31_compact(unsigned char *ptr, zbx_uint32_t value)
{
if (0x7f >= value)
{
ptr[0] = (unsigned char)value;
return 1;
}
else
{
unsigned char buf[6];
int pos = sizeof(buf) - 1;
zbx_uint32_t len;
while (value > (zbx_uint32_t)(0x3f >> (sizeof(buf) - pos)))
{
buf[pos] = 0x80 | (value & 0x3f);
value >>= 6;
pos--;
}
buf[pos] = value | (0xfe << (pos + 1));
len = sizeof(buf) - pos;
memcpy(ptr, buf + pos, len);
return len;
}
}
/******************************************************************************
* *
* Function: zbx_deserialize_uint31_compact *
* *
* Purpose: deserialize 31 bit unsigned integer from utf-8 like byte stream *
* *
* Parameters: ptr - [IN] the byte strem *
* value - [OUT] the deserialized value *
* *
* Return value: The number of bytes read from byte strean. *
* *
******************************************************************************/
zbx_uint32_t zbx_deserialize_uint31_compact(const unsigned char *ptr, zbx_uint32_t *value)
{
if (0 == (*ptr & 0x80))
{
*value = *ptr;
return 1;
}
else
{
int pos = 2, i;
while (0 != (*ptr & (0x80 >> pos)))
pos++;
*value = *ptr & (0xff >> (pos + 1));
for (i = 1; i < pos; i++)
{
*value <<= 6;
*value |= (*(++ptr)) & 0x3f;
}
return pos;
}
}
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