Add -a option (SUSv3) to split(1).

Submitted by:	Tim J. Robbins <tim@robbins.dropbear.id.au>
MFC after:	1 month

usr.bin/split/split.1

@@ -40,6 +40,7 @@
 .Nd split a file into pieces
 .Sh SYNOPSIS
 .Nm
+.Op Fl a Ar suffix_length
 .Op Fl b Ar byte_count[k|m]
 .Op Fl l Ar line_count
 .Op Fl p Ar pattern
@@ -54,6 +55,10 @@ and breaks it up into files of 1000 lines each.
 .Pp
 The options are as follows:
 .Bl -tag -width Ds
+.It Fl a
+Use
+.Ar suffix_length
+letters to form the suffix of the file name.
 .It Fl b
 Create smaller files
 .Ar byte_count
@@ -89,14 +94,20 @@ of the input file which is to be split.
 If a second additional argument is specified, it is used as a prefix
 for the names of the files into which the file is split.
 In this case, each file into which the file is split is named by the
-prefix followed by a lexically ordered suffix in the range of
-.Dq Li aa-zz .
+prefix followed by a lexically ordered suffix using
+.Ar suffix_length
+characters in the range
+.Dq Li a-z .
+If
+.Fl a
+is not specified, two letters are used as the suffix.
 .Pp
 If the
 .Ar name
 argument is not specified, the file is split into lexically ordered
-files named in the range of
-.Dq Li xaa-zzz .
+files named with prefixes in the range of
+.Dq Li x-z
+and with suffixes as above.
 .Sh BUGS
 For historical reasons, if you specify
 .Ar name ,
@@ -104,6 +115,9 @@ For historical reasons, if you specify
 can only create 676 separate
 files.
 The default naming convention allows 2028 separate files.
+The
+.Fl a
+option can be used to work around this limitation.
 .Pp
 The maximum line length for matching patterns is 65536.
 .Sh SEE ALSO

usr.bin/split/split.c

@@ -67,6 +67,7 @@ char	 bfr[MAXBSIZE];			/* I/O buffer. */
 char	 fname[MAXPATHLEN];		/* File name prefix. */
 regex_t	 rgx;
 int	 pflag;
+long	 sufflen = 2;			/* File name suffix length. */
 
 void newfile __P((void));
 void split1 __P((void));
@@ -81,7 +82,7 @@ main(argc, argv)
 	int ch;
 	char *ep, *p;
 
-	while ((ch = getopt(argc, argv, "-0123456789b:l:p:")) != -1)
+	while ((ch = getopt(argc, argv, "-0123456789a:b:l:p:")) != -1)
 		switch (ch) {
 		case '0': case '1': case '2': case '3': case '4':
 		case '5': case '6': case '7': case '8': case '9':
@@ -106,6 +107,11 @@ main(argc, argv)
 				usage();
 			ifd = 0;
 			break;
+		case 'a':		/* Suffix length */
+			if ((sufflen = strtol(optarg, &ep, 10)) <= 0 || *ep)
+				errx(EX_USAGE,
+				    "%s: illegal suffix length", optarg);
+			break;
 		case 'b':		/* Byte count. */
 			if ((bytecnt = strtoq(optarg, &ep, 10)) <= 0 ||
 			    (*ep != '\0' && *ep != 'k' && *ep != 'm'))
@@ -145,6 +151,8 @@ main(argc, argv)
 	if (*argv != NULL)
 		usage();
 
+	if (strlen(fname) + (unsigned long)sufflen >= sizeof(fname))
+		errx(EX_USAGE, "suffix is too long");
 	if (pflag && (numlines != 0 || bytecnt != 0))
 		usage();
 
@@ -273,6 +281,7 @@ split2()
 void
 newfile()
 {
+	long i, maxfiles, tfnum;
 	static long fnum;
 	static int defname;
 	static char *fpnt;
@@ -288,19 +297,32 @@ newfile()
 		}
 		ofd = fileno(stdout);
 	}
+
+	/* maxfiles = 26^sufflen, but don't use libm. */
+	for (maxfiles = 1, i = 0; i < sufflen; i++)
+		if ((maxfiles *= 26) <= 0)
+			errx(EX_USAGE, "suffix is too long (max %ld)", i);
+
 	/*
 	 * Hack to increase max files; original code wandered through
-	 * magic characters.  Maximum files is 3 * 26 * 26 == 2028
+	 * magic characters.
 	 */
-#define MAXFILES	676
-	if (fnum == MAXFILES) {
+	if (fnum == maxfiles) {
 		if (!defname || fname[0] == 'z')
 			errx(EX_DATAERR, "too many files");
 		++fname[0];
 		fnum = 0;
 	}
-	fpnt[0] = fnum / 26 + 'a';
-	fpnt[1] = fnum % 26 + 'a';
+
+	/* Generate suffix of sufflen letters */
+	tfnum = fnum;
+	i = sufflen - 1;
+	do {
+		fpnt[i] = tfnum % 26 + 'a';
+		tfnum /= 26;
+	} while (i-- > 0);
+	fpnt[sufflen] = '\0';
+
 	++fnum;
 	if (!freopen(fname, "w", stdout))
 		err(EX_IOERR, "%s", fname);
@@ -311,6 +333,8 @@ static void
 usage()
 {
 	(void)fprintf(stderr,
-"usage: split [-b byte_count] [-l line_count] [-p pattern] [file [prefix]]\n");
+"usage: split [-a sufflen] [-b byte_count] [-l line_count] [-p pattern]\n");
+	(void)fprintf(stderr,
+"             [file [prefix]]\n");
 	exit(EX_USAGE);
 }