gcode_interpreter/parser.c

/*
 * parser.c
 *
 *  Created on: 10.04.2018
 *      Author: julian
 */

#include "parser.h"
#include <stdio.h>

int isWhite(char c) {
	return c == ' ' || c == '\t' || c == '\r' || c == '\n';
}

int isNumber(char c) {
	return c >= '0' && c <= '9';
}

// point that splits real numbers
int isPoint(char c) {
	return c == '.' || c == ',';
}

char toLower(char in) {
	if (in >= 'A' && in <= 'Z') {
		return in - 'A' + 'a';
	}

	return in;
}

char toUpper(char in) {
	if (in >= 'a' && in <= 'z') {
		return in - 'a' + 'A';
	}

	return in;
}

void skipWhite(const char ** start, const char * end) {
	if (!start) return;

	while(*start < end && isWhite(**start)) {
		++*start;
	}
}

// returns 1 on success
int asInt(int * result, const char ** start, const char * end) {
	if (!result || !start) return 0;

	skipWhite(start, end);
	if (*start == end) { return 0; }

	int inv = 0;
	unsigned int count = 0;

	switch(**start) {
	case '-':
		inv = 1;
	case '+':
		++*start;
		break;
	}

	*result = 0;

	for(;*start != end && isNumber(**start); ++*start, count++) {
		*result *= 10;
		*result += **start - '0';
	}

	if (inv) {
		*result = -*result;
	}

	return count > 0;
}

int asFloat(float *result, const char **start, const char * end) {
	if (!result || !start ) return 0;
	skipWhite(start, end);
	if (*start == end) return 0;

	int nominator = 0;
	float denomiator = 0.f;

	if (!asInt(&nominator, start, end)) return 0;

	if (isPoint(**start)) {
		const char * denom_end = *start +1;

		while(denom_end < end && isNumber(*denom_end))
			denom_end++;


		while(--denom_end > *start) {
			denomiator += *denom_end - '0';
			denomiator /= 10.f;
		}
	}

	*result = (float)(nominator) + denomiator;
	return 1;
}

int nextArgument(argument_t* result, const char ** start, const char * end) {
	if (!start | !result) return 0;
	skipWhite(start, end);
	if (*start == end) return 0;

	result->c = **start;
	++*start;
	asFloat(&result->num, start, end);
	return 1;
}

volatile int notok;

void gcode(const char * start, const char * end) {
	int code;
	skipWhite(&start, end);

	if (start == end || !asInt(&code, &start, end)) {
		error("expected number after G\n");
		return;
	}

	switch(code) {
	case 0:
	case 1:
		// move
		move(start, end);
		break;
	case 28:
		// home;
		home(start, end);
		break;
	case 90:
		set_move_absolute();
		break;
	case 91:
		set_move_relative();
		break;
	default:
		error("unknown gcode: %d\n",code);
	}
}

void mcode(const char * start, const char * end) {
	int code;
	skipWhite(&start, end);

	if (start == end || !asInt(&code, &start, end)) {
		printf("expected number after M\n");
		return;
	}

	switch(code) {
	case 500:
		// save config data
		printf("save config data\n");
		break;
	case 502:
		printf("restore default config\n");
		break;
	default:
		error("no Mcode: %d\n", code);
	}
}

void parse(const char * start, const char * end) {
	notok = 0;

	skipWhite(&start, end);
	if (start == end) return;

	switch (toLower(*start)) {
	case 'g':
		gcode(++start, end);
		break;
	case 'm':
		mcode(++start, end);
		break;
	case '?':
		state(++start, end);
		return;
	default:
		error("expected g or m codes\n");
	}

	if (notok) { return; }

	printf("ok\n");
}