brainfuck to c converter

brainfucc.c

/* 
 * A simple, non-optimizing brainfuck to C translator.
 * 2010-08-31 - Version 1.0   (Cory Burgett)
 *
 * This code is hereby placed into the public domain.
 *
 * Originally located at: http://www4.ncsu.edu/~cmburget/brainfucc.c
 * based on https://gist.github.com/939687.git
 */

#include <stdio.h>


int is_arith(char c) {
	switch (c) {
		case '>': 
		case '<': 
		case '+': 
		case '-':
			return -1; break;
		default: return 0; break;
	}
}

int is_data(char c) {
	switch (c) {
		case '.': 
		case ',': 
		case '[': 
		case ']': 
			return -1; break;
		default: return 0; break;
	}
}

void print_depth(FILE *out, unsigned depth) {
	//fprintf(out, "// depth = %u\n", depth);
	for (; depth > 0; --depth)
		fprintf(out, "\t");
}


void print_arith(FILE *out, unsigned depth, char c, unsigned repetitions, unsigned char_nr) {
	//fprintf(out, "// char = %c\n", c);
	#if 1
	print_depth(out, depth);
	switch (c) {
		case '>': fprintf(out, "cell += %u;", repetitions); break;
		case '<': fprintf(out, "cell -= %u;", repetitions); break;
		case '+': fprintf(out, "*cell += %u;", repetitions); break;
		case '-': fprintf(out, "*cell -= %u;", repetitions); break;
		default: break;
	}
	fprintf(out, " // %u-%u\n", char_nr + 1 - repetitions, char_nr);
	#else
	unsigned i;
	for (i = 0; i < repetitions; i++) {
		print_depth(out, depth);
		switch (c) {
			case '>': fprintf(out, "++cell;\n"); break;
			case '<': fprintf(out, "--cell;\n"); break;
			case '+': fprintf(out, "++*cell;\n"); break;
			case '-': fprintf(out, "--*cell;\n"); break;
			default: break;
		}
	}
	#endif
}

void print_data(FILE *out, unsigned *depth, char c, unsigned char_nr){
	//fprintf(out, "// char = %c\n", c);
	if (']' == c) {
		*depth -= 1;
	}
	print_depth(out, *depth);
	switch (c) {
		case '.': fprintf(out, "putchar(*cell);"); break;
		case ',': fprintf(out, "*cell = getchar();"); break;
		case '[': fprintf(out, "while (*cell) {"); break;
		case ']': fprintf(out, "}"); break;
		default: break;
	}
	fprintf(out, " // %u\n", char_nr);
	if ('[' == c) {
		*depth += 1;
	}
}

int main(int argc, char **argv)
{
	FILE *in = stdin, *out = stdout;
	int c;
	int cellsize = 30000;
	unsigned times = 0;
	char prev = '\0';
	unsigned depth = 1;
	unsigned char_nr = -1;

	fprintf(out,
		"#include <stdio.h>\n"
		"#include <stdlib.h>\n\n"
		"int main(int argc, char **argv)\n{\n"
		"\tunsigned char *cell = calloc(%d, 1);\n"
		"\tunsigned char *cells = cell;\n"
		"\tif (!cell) {\n"
		"\t\tfprintf(stderr, \"Error allocating memory.\\n\");\n"
		"\t\treturn 1;\n"
		"\t}\n\n", cellsize
	);

	while ((c = getc(in)) != EOF) {
		++char_nr;
		if (is_arith(c) && prev == c) {
			++times;
			continue;
		}

		if (times > 0) {
			print_arith(out, depth, prev, times, char_nr - 1);
			times = 0;
		}

		prev = c;
		if (is_arith(c)) {
			++times;
		} else {
			print_data(out, &depth, c, char_nr);
		}
	}

	if (times > 0) {
		print_arith(out, depth, prev, times, char_nr);
	}
	
	fprintf(out, "\n\tfree(cells);\n\treturn 0;\n}\n\n");
}