split: fixes

- -b argument required, don't allow -b <= 0.
- -l argument required, don't allow -l <= 0.
- usage() and argument parsing: sort flags.
- don't write 0 size file, get rid of goto reproducable with:
  printf 'a' | split -b 1.
- close FILE *in if != stdin.
- mark split as finished in README.
- codestyle fixes.

README

@@ -60,7 +60,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =* setsid          non-posix                       none
 =* sleep           yes                             none
    sort            no                              -m, -o, -d, -f, -i
-   split           yes                             none
+=* split           yes                             none
 =  sponge          non-posix                       none
    strings         no                              -a, -n, -t
 =  sync            non-posix                       none

split.c

@@ -8,38 +8,66 @@
 
 #include "util.h"
 
-static int itostr(char *, int, int);
+static int base = 26, start = 'a';
-static FILE *nextfile(FILE *, char *, int, int);
+
+int
+itostr(char *str, int x, int n)
+{
+	str[n] = '\0';
+	while (n-- > 0) {
+		str[n] = start + (x % base);
+		x /= base;
+	}
+	if (x)
+		return -1;
+	return 0;
+}
+
+FILE *
+nextfile(FILE *f, char *buf, int plen, int slen)
+{
+	static int filecount = 0;
+
+	if (f)
+		fclose(f);
+	if (itostr(buf + plen, filecount++, slen) < 0)
+		return NULL;
+
+	if (!(f = fopen(buf, "w")))
+		eprintf("'%s':", buf);
+	return f;
+}
 
 static void
 usage(void)
 {
-	eprintf("usage: split [-d] [-a len] [-b [bytes[k|m|g]]] [-l [lines]] [input [prefix]]\n");
+	eprintf("usage: %s [-a len] [-b bytes[k|m|g]] [-d] [-l lines] "
+	        "[input [prefix]]\n", argv0);
 }
 
-static int base = 26, start = 'a';
-
 int
 main(int argc, char *argv[])
 {
-	int plen, slen = 2;
+	FILE *in = stdin, *out = NULL;
-	int ch;
 	char name[NAME_MAX + 1];
 	char *prefix = "x";
 	char *file = NULL;
 	char *tmp, *end;
 	size_t size = 1000, scale = 1, n;
-	int always = 0;
+	int ch, plen, slen = 2, always = 0;
-	FILE *in = stdin, *out = NULL;
+	long l;
 
 	ARGBEGIN {
+	case 'a':
+		slen = estrtonum(EARGF(usage()), 0, INT_MAX);
+		break;
 	case 'b':
 		always = 1;
-		tmp = ARGF();
+		tmp = EARGF(usage());
-		if (!tmp)
+		l = strtol(tmp, &end, 10);
-			break;
+		if (l <= 0)
-
+			eprintf("invalid number of bytes: %s\n", tmp);
-		size = strtoull(tmp, &end, 10);
+		size = (size_t)l;
 		if (!*end)
 			break;
 		switch (toupper((int)*end)) {
@@ -59,19 +87,15 @@ main(int argc, char *argv[])
 			eprintf("'%s': out of range\n", tmp);
 		size *= scale;
 		break;
-	case 'l':
-		always = 0;
-		tmp = ARGF();
-		if (tmp)
-			size = estrtonum(tmp, 0, MIN(LLONG_MAX, SIZE_MAX));
-		break;
-	case 'a':
-		slen = estrtonum(EARGF(usage()), 0, INT_MAX);
-		break;
 	case 'd':
 		base = 10;
 		start = '0';
 		break;
+	case 'l':
+		always = 0;
+		tmp = EARGF(usage());
+		size = estrtonum(tmp, 1, MIN(LLONG_MAX, SIZE_MAX));
+		break;
 	default:
 		usage();
 	} ARGEND;
@@ -89,53 +113,23 @@ main(int argc, char *argv[])
 	strlcpy(name, prefix, sizeof(name));
 
 	if (file && strcmp(file, "-") != 0) {
-		in = fopen(file, "r");
+		if (!(in = fopen(file, "r")))
-		if (!in)
 			eprintf("'%s':", file);
 	}
 
-Nextfile:
-	while ((out = nextfile(out, name, plen, slen))) {
 	n = 0;
 	while ((ch = getc(in)) != EOF) {
-			putc(ch, out);
+		if (!out || n >= size) {
+			if (!(out = nextfile(out, name, plen, slen)))
+				eprintf("fopen: %s:", name);
+			n = 0;
+		}
 		n += (always || ch == '\n');
-			if (n >= size)
+		putc(ch, out);
-				goto Nextfile;
 	}
+	if (in != stdin)
+		fclose(in);
+	if (out)
 		fclose(out);
-		break;
-	}
 	return 0;
 }
-
-int
-itostr(char *str, int x, int n)
-{
-	str[n] = '\0';
-	while (n-- > 0) {
-		str[n] = start + (x % base);
-		x /= base;
-	}
-	if (x)
-		return -1;
-	return 0;
-}
-
-FILE *
-nextfile(FILE *f, char *buf, int plen, int slen)
-{
-	static int n = 0;
-	int s;
-
-	if (f)
-		fclose(f);
-	s = itostr(buf+plen, n++, slen);
-	if (s < 0)
-		return NULL;
-
-	f = fopen(buf, "w");
-	if (!f)
-		eprintf("'%s':", buf);
-	return f;
-}