Give units a bit of a cleanup:

1) Fix a bug where the recursion on prefixes where if recusrion failed
	then the next attempt started too far along the string.
2) Up some internal limits that we were about to hit off.
3) Change the constness and signedness of some things and complete missing
	prototypes.
4) Remove the readerror function 'cos it could print out the wrong
	wrong file name. Replace it with more useful error messages.
5) Use sizeof when passing buffers to fgets.
6) Warn about empty prefix definitions.

Reviewed by:	iedowse

1 files changed, 26 insertions, 32 deletions

diff --git a/usr.bin/units/units.c b/usr.bin/units/units.c
index c0ba09a..603de30 100644
--- a/usr.bin/units/units.c
+++ b/usr.bin/units/units.c
@@ -36,13 +36,13 @@ static const char rcsid[] =
 #endif
 
 #define MAXUNITS 1000
-#define MAXPREFIXES 50
+#define MAXPREFIXES 100
 
 #define MAXSUBUNITS 500
 
 #define PRIMITIVECHAR '!'
 
-char *powerstring = "^";
+const char *powerstring = "^";
 
 struct {
 	char *uname;
@@ -61,10 +61,10 @@ struct {
 }      prefixtable[MAXPREFIXES];
 
 
-char *NULLUNIT = "";
+char NULLUNIT[] = "";
 
 #ifdef MSDOS
-#define SEPERATOR      ";"
+#define SEPARATOR      ";"
 #else
 #define SEPARATOR      ":"
 #endif
@@ -74,7 +74,7 @@ int prefixcount;
 
 
 char *
-dupstr(char *str)
+dupstr(const char *str)
 {
 	char *ret;
 
@@ -87,17 +87,10 @@ dupstr(char *str)
 
 
 void 
-readerror(int linenum)
-{
-	warnx("error in units file '%s' line %d", UNITSFILE, linenum);
-}
-
-
-void 
-readunits(char *userfile)
+readunits(const char *userfile)
 {
 	FILE *unitfile;
-	char line[80], *lineptr;
+	char line[512], *lineptr;
 	int len, linenum, i;
 
 	unitcount = 0;
@@ -131,7 +124,7 @@ readunits(char *userfile)
 		}
 	}
 	while (!feof(unitfile)) {
-		if (!fgets(line, 79, unitfile))
+		if (!fgets(line, sizeof(line), unitfile))
 			break;
 		linenum++;
 		lineptr = line;
@@ -156,12 +149,13 @@ readunits(char *userfile)
 					continue;
 				}
 			lineptr += len + 1;
-			if (!strlen(lineptr)) {
-				readerror(linenum);
-				continue;
-			}
 			lineptr += strspn(lineptr, " \n\t");
 			len = strcspn(lineptr, "\n\t");
+			if (len == 0) {
+				warnx("unexpected end of prefix on line %d",
+				    linenum);
+				continue;
+			}
 			lineptr[len] = 0;
 			prefixtable[prefixcount++].prefixval = dupstr(lineptr);
 		}
@@ -180,7 +174,8 @@ readunits(char *userfile)
 			lineptr += len + 1;
 			lineptr += strspn(lineptr, " \n\t");
 			if (!strlen(lineptr)) {
-				readerror(linenum);
+				warnx("unexpected end of unit on line %d",
+				    linenum);
 				continue;
 			}
 			len = strcspn(lineptr, "\n\t");
@@ -263,7 +258,7 @@ showunit(struct unittype * theunit)
 
 
 void 
-zeroerror()
+zeroerror(void)
 {
 	warnx("unit reduces to zero");
 }
@@ -366,7 +361,7 @@ addunit(struct unittype * theunit, char *toadd, int flip)
 int 
 compare(const void *item1, const void *item2)
 {
-	return strcmp(*(char **) item1, *(char **) item2);
+	return strcmp(*(const char **) item1, *(const char **) item2);
 }
 
 
@@ -374,7 +369,7 @@ void
 sortunit(struct unittype * theunit)
 {
 	char **ptr;
-	int count;
+	unsigned int count;
 
 	for (count = 0, ptr = theunit->numerator; *ptr; ptr++, count++);
 	qsort(theunit->numerator, count, sizeof(char *), compare);
@@ -420,7 +415,7 @@ static char buffer[100];	/* buffer for lookupunit answers with
 				   prefixes */
 
 char *
-lookupunit(char *unit)
+lookupunit(const char *unit)
 {
 	int i;
 	char *copy;
@@ -465,12 +460,11 @@ lookupunit(char *unit)
 		free(copy);
 	}
 	for (i = 0; i < prefixcount; i++) {
-		if (!strncmp(prefixtable[i].prefixname, unit,
-			strlen(prefixtable[i].prefixname))) {
-			unit += strlen(prefixtable[i].prefixname);
-			if (!strlen(unit) || lookupunit(unit)) {
+		size_t len = strlen(prefixtable[i].prefixname);
+		if (!strncmp(prefixtable[i].prefixname, unit, len)) {
+			if (!strlen(unit + len) || lookupunit(unit + len)) {
 				snprintf(buffer, sizeof(buffer), "%s %s",
-				    prefixtable[i].prefixval, unit);
+				    prefixtable[i].prefixval, unit + len);
 				return buffer;
 			}
 		}
@@ -608,7 +602,7 @@ showanswer(struct unittype * have, struct unittype * want)
 
 
 void 
-usage()
+usage(void)
 {
 	fprintf(stderr,
 		"usage: units [-f unitsfile] [-q] [-v] [from-unit to-unit]\n");
@@ -670,7 +664,7 @@ main(int argc, char **argv)
 				initializeunit(&have);
 				if (!quiet)
 					printf("You have: ");
-				if (!fgets(havestr, 80, stdin)) {
+				if (!fgets(havestr, sizeof(havestr), stdin)) {
 					if (!quiet)
 						putchar('\n');
 					exit(0);
@@ -681,7 +675,7 @@ main(int argc, char **argv)
 				initializeunit(&want);
 				if (!quiet)
 					printf("You want: ");
-				if (!fgets(wantstr, 80, stdin)) {
+				if (!fgets(wantstr, sizeof(wantstr), stdin)) {
 					if (!quiet)
 						putchar('\n');
 					exit(0);