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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, version 3.
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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