Simple brainfuck compiler in less than 100 lines of C

brainfuck_compiler.c

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

char* read_file( char* file_name ) {
	FILE* file = fopen( file_name, "r" );
	if ( file == NULL ) {
		printf( "Could not open input file `%s`.\n", file_name );
		exit( 1 );
	}

	// Get file size
	fseek( file, 0, SEEK_END );
	long file_size = ftell( file );
	fseek( file, 0, SEEK_SET );

	// Allocate memory for file data
	char* code = malloc( file_size );

	// Read file data
	int c;
	size_t n = 0;
	while ( ( c = fgetc( file ) ) != EOF ) {
		code[n++] = (char)c;
	}

	// Terminate c-string with null character
	code[n] = '\0';

	return code;
}

void generate_output( char* code, char* output_path ) {
	FILE* file = fopen( output_path, "w" );
	if ( file == NULL ) {
		printf( "Could not open output file `%s`.\n", output_path );
		exit( 1 );
	}

	// Write header with defines to slim down final file size
	fprintf( file,
			 "#include <stdio.h>\n"
			 "#include <stdlib.h>\n"
			 "#define A ++p\n"
			 "#define B --p\n"
			 "#define C ++*p\n"
			 "#define D --*p\n"
			 "#define E putchar(*p)\n"
			 "#define F *p=getchar()\n"
			 "#define G while(*p)\n"
			 "int main(){char*p=malloc(1024*sizeof(char));" );

	// Write code to file
	for ( char c = *code; c != '\0'; c = *++code ) {
		switch ( c ) {
			case '>':
				fprintf( file, "A;" );
				break;
			case '<':
				fprintf( file, "B;" );
				break;
			case '+':
				fprintf( file, "C;" );
				break;
			case '-':
				fprintf( file, "D;" );
				break;
			case '.':
				fprintf( file, "E;" );
				break;
			case ',':
				fprintf( file, "F;" );
				break;
			case '[':
				fprintf( file, "G{" );
				break;
			case ']':
				fprintf( file, "}" );
				break;
			default:
				break;
		}
	}

	// Write footer and close
	fprintf( file, "return 0;}" );
	fclose( file );
}

int main( int argc, char* argv[] ) {
	if ( argc < 2 ) {
		printf( "Usage: %s <input_file> [output_file]\n", argv[0] );
		exit( 1 );
	}
	char* code = read_file( argv[1] );

	// Write output to output.c (unless a second argument is given)
	generate_output( code, argc >= 3 ? argv[2] : "output.c" );
	return 0;
}