more cleaning

lowercase/lowercase.c

@@ -0,0 +1,73 @@
+#include <ascii.h> /* ASCII_MAX_VALUE */
+#include <stdbool.h> /* bool */
+#include <stdio.h> /* fprintf(3), getc(3), putc(3), stderr, stdin, stdout */
+#include <stdlib.h> /* exit(3) */
+#include <sysexits.h> /* EX_OK, EX_USAGE, EX_SOFTWARE */
+#include <unistd.h> /* getopt(3) */
+
+/* Enable Unicode support using official Unicode library. */
+#ifdef    USE_ICU
+#	include <unicode/uchar.h> /* UCHAR_MAX_VALUE, u_tolower(3) */
+#	include <unicode/umachine.h> /* UChar32 */
+#	include <unicode/ustdio.h> /* u_fgetc(3) */
+#endif /* USE_ICU */
+
+#define PROGRAM_NAME "lowercase"
+
+void
+usage(char *name){
+	fprintf(stderr, "Usage: %s (-f)\n", name);
+	exit(EX_USAGE);
+}
+
+int main(int argc, char *argv[]){
+#ifdef USE_ICU
+	UChar32
+#else
+	int
+#endif
+		c; /* iterating over character stream */
+	int d; /* iterating over getopt */
+	bool force;
+	force = false;
+
+	while((d = getopt(argc, argv, "f")) != -1)
+		switch(d){
+		case 'f':
+			force = true;
+			break;
+		case '?':
+			usage(argv[0] != NULL ? argv[0] : PROGRAM_NAME);
+			break;
+		}
+	if(argv[optind] != NULL) /* don't accept arguments */
+		usage(argv[0] != NULL ? argv[0] : PROGRAM_NAME);
+
+#ifdef USE_ICU
+	while((c = u_fgetc(stdin)) != U_EOF){
+#else
+	while((c = getc(stdin)) != EOF){
+#endif
+		if(c <= ASCII_MAX_VALUE)
+			c += ('a' - 'A') * (c >= 'A' && c <= 'Z');
+#ifdef USE_ICU
+		else if(c <= UCHAR_MAX_VALUE)
+			c = u_tolower(c);
+#endif
+		else if(!force){ /* past supported */
+			fprintf(
+				stderr,
+				"%s: Sorry, extra-ASCII characters are not yet"
+				" supported!\n",
+				argv[0] != NULL ? argv[0] : PROGRAM_NAME
+			);
+			return EX_SOFTWARE;
+		}
+#ifdef USE_ICU
+		u_fputc(c, stdout);
+#else
+		putc(c, stdout);
+#endif
+	}
+	return EX_OK;
+}