seq: some cleanup

seq.1

@@ -9,20 +9,22 @@ seq \- print a sequence of numbers
 .RB [ \-s
 .IR separator ]
 .RI [ start
-.RI [step] ]
+.RI [ step ]]
 .RI end
 .SH DESCRIPTION
 .B seq 
-will print numbers from 
-.I START
-to
-.I END,
-in steps of
-.I STEP. 
+will print a sequence of numbers from 
+.I start
+(default 1) to
+.IR end ,
+in
+.IR step
+intervals (default 1).
 .SH OPTIONS
 .TP
 .BI \-f " format"
-specifies the printf style for the output lines
+specifies the format used for output lines, as per
+.IR printf (3).
 .TP
 .BI \-s " separator"
 specifies the separator to print between output lines

seq.c

@@ -1,113 +1,29 @@
 /* See LICENSE file for copyright and license details. */
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <stdbool.h>
-#include <libgen.h>
-
 #include "util.h"
 
-#define MAX(a, b) (((a) > (b))? (a):(b))
-
-int
-validfloat(char *fmt)
-{
-	char *end;
-
-	fmt += strspn(fmt, " ");
-	strtod(fmt, &end);
-	if (fmt == end || end != fmt + strlen(fmt))
-		return 0;
-
-	return 1;
-}
-
-int
-digitsleft(char *d)
-{
-	char *exp;
-	int shift;
-
-	if (d[0] == '+')
-		d++;
-	exp = strpbrk(d, "eE");
-	shift = exp? atoi(exp+1) : 0;
-
-	return MAX(0, strspn(d, "-0123456789")+shift);
-}
-
-int
-digitsright(char *d)
-{
-	char *exp;
-	int shift, after;
-
-	exp = strpbrk(d, "eE");
-	shift = exp ? atoi(exp+1) : 0;
-	after = (d = strchr(d, '.'))? strspn(d+1, "0123456789") : 0;
-
-	return MAX(0, after-shift);
-}
-
-int
-validfmt(char *fmt)
-{
-	int occur;
-
-	occur = 0;
-
-NonFormat:
-	while(*fmt) {
-		if (*fmt++ == '%')
-			goto Format;
-	}
-	return (occur == 1);
-Format:
-	if (*fmt == '%') {
-		fmt++;
-		goto NonFormat;
-	}
-	fmt += strspn(fmt, "-+#0 '");
-	fmt += strspn(fmt, "0123456789");
-	if (*fmt == '.') {
-		fmt ++;
-		fmt += strspn(fmt, "0123456789");
-	}
-	if (*fmt == 'L')
-		fmt++;
-	if (*fmt == '\0')
-		return 0;
-	if (strchr("fFgGeEaA", *fmt)) {
-		occur++;
-		goto NonFormat;
-	}
-	return 0;
-}
+static int digitsleft(const char *);
+static int digitsright(const char *);
+static double estrtod(const char *);
+static bool validfmt(const char *);
 
 int
 main(int argc, char *argv[])
 {
-	char c, *fmt, ftmp[4096], *sep, *starts, *steps, *ends;
-	bool wflag, fflag;
+	const char *starts = "1", *steps = "1", *ends = "1", *sep = "\n";
+	bool fflag = false, wflag = false;
+	char c, ftmp[BUFSIZ], *fmt = ftmp;
 	double start, step, end, out, dir;
-	int left, right;
 
-	sep = "\n";
-	fmt = ftmp;
-
-	wflag = false;
-	fflag = false;
-
-	starts = "1";
-	steps = "1";
-	ends = "1";
-
-	while((c = getopt(argc, argv, "f:s:w")) != -1) {
+	while((c = getopt(argc, argv, "f:s:w")) != -1)
 		switch(c) {
 		case 'f':
-			if (!validfmt(optarg))
-				eprintf("invalid format.\n");
+			if(!validfmt(optarg))
+				eprintf("%s: invalid format\n", optarg);
 			fmt = optarg;
 			fflag = true;
 			break;
@@ -118,10 +34,6 @@ main(int argc, char *argv[])
 			wflag = true;
 			break;
 		}
-	}
-
-	if (wflag && fflag)
-		eprintf("-f and -w cannot be combined.\n");
 
 	switch(argc-optind) {
 	case 3:
@@ -131,59 +43,116 @@ main(int argc, char *argv[])
 		break;
 	case 2:
 		starts = argv[optind++];
-		ends = argv[optind++];
-		break;
+		/* fallthrough */
 	case 1:
 		ends = argv[optind++];
 		break;
 	default:
-		eprintf("usage: %s [-w] [-f fmt] [-s separator] "
-				"[start [step]] end\n",
-				basename(argv[0]));
+		eprintf("usage: %s [-w] [-f fmt] [-s separator] [start [step]] end\n", argv[0]);
 	}
+	start = estrtod(starts);
+	step  = estrtod(steps);
+	end   = estrtod(ends);
 
-	if (!validfloat(starts))
-		eprintf("start is not a valid float.\n");
-	if (!validfloat(steps))
-		eprintf("step is not a valid float.\n");
-	if (!validfloat(ends))
-		eprintf("end is not a valid float.\n");
-
-	start = atof(starts);
-	step = atof(steps);
-	end = atof(ends);
-	dir = (step > 0)? 1.0 : -1.0;
-
-	if (step == 0)
-		return EXIT_FAILURE;
-	if (start * dir > end * dir)
+	dir = (step > 0) ? 1.0 : -1.0;
+	if(step == 0 || start * dir > end * dir)
 		return EXIT_FAILURE;
 
-	right = MAX(digitsright(starts),
-			MAX(digitsright(ends),
-				digitsright(steps)));
-	if (wflag) {
-		left = MAX(digitsleft(starts), digitsleft(ends));
+	if(fmt == ftmp) {
+		int right = MAX(digitsright(starts),
+		            MAX(digitsright(ends),
+		                digitsright(steps)));
 
-		snprintf(ftmp, sizeof(ftmp), "%%0%d.%df",
-				right+left+(right != 0),
-				right);
-	} else if (fmt == ftmp) {
-		snprintf(ftmp, sizeof(ftmp), "%%.%df", right);
-	}
+		if(wflag) {
+			int left = MAX(digitsleft(starts), digitsleft(ends));
 
-	for (out = start;;) {
-		printf(fmt, out);
-
-		out += step;
-		if (out * dir <= end * dir) {
-			printf("%s", sep);
-		} else {
-			break;
+			snprintf(ftmp, sizeof ftmp, "%%0%d.%df", right+left+(right != 0), right);
 		}
+		else
+			snprintf(ftmp, sizeof ftmp, "%%.%df", right);
+	}
+	for(out = start; out * dir <= end * dir; out += step) {
+		if(out != start)
+			fputs(sep, stdout);
+		printf(fmt, out);
 	}
 	printf("\n");
 
 	return EXIT_SUCCESS;
 }
 
+int
+digitsleft(const char *d)
+{
+	char *exp;
+	int shift;
+
+	if(*d == '+')
+		d++;
+	exp = strpbrk(d, "eE");
+	shift = exp ? atoi(&exp[1]) : 0;
+
+	return MAX(0, strspn(d, "-0123456789")+shift);
+}
+
+int
+digitsright(const char *d)
+{
+	char *exp;
+	int shift, after;
+
+	exp = strpbrk(d, "eE");
+	shift = exp ? atoi(&exp[1]) : 0;
+	after = (d = strchr(d, '.')) ? strspn(&d[1], "0123456789") : 0;
+
+	return MAX(0, after-shift);
+}
+
+double
+estrtod(const char *s)
+{
+	char *end;
+	double d;
+
+	d = strtod(s, &end);
+	if(end == s || *end != '\0')
+		eprintf("%s: not a real number\n", s);
+	return d;
+}
+
+bool
+validfmt(const char *fmt)
+{
+	int occur = 0;
+
+literal:
+	while(*fmt)
+		if(*fmt++ == '%')
+			goto format;
+	return occur == 1;
+
+format:
+	if(*fmt == '%') {
+		fmt++;
+		goto literal;
+	}
+	fmt += strspn(fmt, "-+#0 '");
+	fmt += strspn(fmt, "0123456789");
+	if(*fmt == '.') {
+		fmt++;
+		fmt += strspn(fmt, "0123456789");
+	}
+	if(*fmt == 'L')
+		fmt++;
+
+	switch(*fmt) {
+	case 'f': case 'F':
+	case 'g': case 'G':
+	case 'e': case 'E':
+	case 'a': case 'A':
+		occur++;
+		goto literal;
+	default:
+		return false;
+	}
+}

util.h

@@ -2,6 +2,9 @@
 
 #define UTF8_POINT(c) (((c) & 0xc0) != 0x80)
 
+#define MIN(x,y)  ((x) < (y) ? (x) : (y))
+#define MAX(x,y)  ((x) > (y) ? (x) : (y))
+
 char *agetcwd(void);
 void apathmax(char **, long *);
 void enmasse(int, char **, int (*)(const char *, const char *));

util/estrtol.c

@@ -12,9 +12,9 @@ estrtol(const char *s, int base)
 	n = strtol(s, &end, base);
 	if(*end != '\0') {
 		if(base == 0)
-			eprintf("%s: not a number\n", s);
+			eprintf("%s: not an integer\n", s);
 		else
-			eprintf("%s: not a base %d number\n", s, base);
+			eprintf("%s: not a base %d integer\n", s, base);
 	}
 	return n;
 }