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/*
(c) Copyright 2012 - 2018 Anton Sviridenko
https://picapica.im
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 3 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, see <https://www.gnu.org/licenses/>.
*/
#include <limits.h>
#include <string.h>
#include "PICA_proto.h"
#include "PICA_msgproc.h"
//возвращает размер сообщения либо UINT_MAX,если количество прочитанных байт недостаточно для определения размера
//либо 0 при ошибочных данных
unsigned int PICA_msggetsize(unsigned char *buf, unsigned int nb, struct PICA_msginfo *msgs, unsigned int nmsg)
{
unsigned int i;
if (nb < 2)
return UINT_MAX;
if (buf[0] != buf[1])
return 0;
for (i = 0; i < nmsg; i++)
if (buf[0] == (unsigned char)msgs[i].msgid)
{
if (msgs[i].fixedsz == PICA_MSG_FIXED_SIZE)
return msgs[i].sz;
else if (msgs[i].fixedsz == PICA_MSG_VAR_SIZE)
{
if (nb >= (msgs[i].sz + 2))
{
unsigned int tail_len = 0;
int j;
#if defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
for (j = 0; j < msgs[i].sz; j++)
((char*)&tail_len)[sizeof(int) - 1 - j] = buf[2 + j];
#else
for (j = 0; j < msgs[i].sz; j++)
((char*)&tail_len)[j] = buf[2 + j];
#endif
return 2 + msgs[i].sz + tail_len;
}
else
return UINT_MAX;
}
}
return 0;
}
//Определяет тип сообщения размера size, находящегося в буфере buf, вызывает соответствующий обработчик и передает обработчику аргумент arg. Возвращает значение, которое вернула функция-обработчик сообщения. Если тип сообщения неизвестен, возвращает 0
unsigned int PICA_processmsg(unsigned char *buf, unsigned int size, void* arg, struct PICA_msginfo *msgs, unsigned int nmsg)
{
int i;
if (buf[0] != buf[1])
return 0;
for (i = 0; i < nmsg; i++)
if (buf[0] == (unsigned char)msgs[i].msgid)
return msgs[i].msgprocfn(buf, size, arg);
return 0;
}
unsigned int PICA_processdatastream(unsigned char *buf, unsigned int *read_pos, void* arg, const struct PICA_msginfo *msgs, unsigned int nmsg)
{
while(*read_pos)
{
unsigned int uret;
uret = PICA_msggetsize(buf, *read_pos, msgs, nmsg);
if (!uret)
return 0;
if (uret > *read_pos)
break;
if (!PICA_processmsg(buf, uret, arg, msgs, nmsg))
return 0;
*read_pos -= uret;
memmove(buf, buf + uret, *read_pos); //сдвиг содержимого буфера к началу
}
return 1;
}
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