#include "stdafx.h"


#include "stdio.h"
#include "stdlib.h"
#include <string.h>


#include "util_hdlc.h"


#define __HDLC_FLAG 0x7E
#define __HDLC_ESC 0x7D
#define __HDLC_COMPL 0x20



void log0(const char* ss)
{

	FILE* fp;
	fp = fopen("log.txt", "ab");

	fwrite(ss, 1, strlen(ss), fp);
	fwrite("\r\n", 1, 2, fp);

	fclose(fp);

}

void log_hex(char* msg, char* buf, int size)
{
	char text[4096];
	char tmp[10];
	int i;

	sprintf(text, "%s - ", msg);

	for(i = 0; i < size; ++i)
	{
		sprintf(tmp, "%02X ", buf[i]);
		strcat(text, tmp);

	}

	strcat(text, "\r\n");

	log0(text);

}

void hdlc_encode(unsigned char* buf, int size, unsigned char* out_buf, int* out_size)
{
	int inx = 0;

	int i;

	out_buf[inx++] = __HDLC_FLAG;	// start flag

	for(i = 0; i < size; ++i)
	{
		if(buf[i] == __HDLC_ESC || buf[i] == __HDLC_FLAG)
		{
			// if esc?
			out_buf[inx++] = __HDLC_ESC;
			out_buf[inx++] = (unsigned char)(buf[i] ^ __HDLC_COMPL);
		}
		else
		{
			out_buf[inx++] = buf[i];
		}
	}
	out_buf[inx++] = __HDLC_FLAG;	// flag


	*out_size = inx;
}

int hdlc_decode(unsigned char* buf, int size, unsigned char* out_buf, int* out_size)
{
	int inx = 0;
	int i;

// size
	if(size < 3)
	{
		return 0;
	}

// start
	if(buf[0] != __HDLC_FLAG)
	{
		return 0;
	}

// decode
	for(i = 1; i < size-1; ++i)
	{
		if(buf[i] == __HDLC_ESC)
		{
			++i;
			out_buf[inx++] = (unsigned char)(buf[i] ^ __HDLC_COMPL);
		}
		else
		{
			out_buf[inx++] = buf[i];
		}
	}

// end
	if(buf[size-1] != __HDLC_FLAG)
		return 0;


	*out_size = inx;
	return 1;
}