Steven Blair / rapid61850example

The goal of this software is to automatically generate C/C++ code which reads and writes GOOSE and Sampled Value packets. Any valid IEC 61850 Substation Configuration Description (SCD) file, describing GOOSE and/or SV communications, can be used as the input. The output code is lightweight and platform-independent, so it can run on a variety of devices, including low-cost microcontrollers. It\'s ideal for rapid-prototyping new protection and control systems that require communications. This mbed project is a simple example of this functionality. Other code: https://github.com/stevenblair/rapid61850 Project homepage: http://personal.strath.ac.uk/steven.m.blair/

decodePacket.c

Committer:
sblair
Date:
2011-10-07
Revision:
0:230c10b228ea
Child:
1:9399d44c2b1a

File content as of revision 0:230c10b228ea:

#include "decodePacket.h"
//#include "svEncodeBasic.h"


// returns size of length field, from first byte
int getLengthFieldSize(unsigned char byte) {
	if (byte <= 126) {
		return 1;
	}
	else {
		return 1 + (byte & 0x7F);
	}
}

//TODO	check this works for all inputs, e.g., buf[1] = 0xFF
int decodeLength(unsigned char *buf) {
	if (buf[0] <= 126) {
		return buf[0];
	}
	else {
		int bytes = (buf[0] & 0x7F);

		if (bytes == 1) {
			return buf[1];
		}
		else if (bytes == 2) {	// assumes max length of 2^15
			return ((buf[1] & 0xFF) << 8) | (buf[2] & 0xFF);
		}
	}

	return 0;
}