hacklib.c NONNULL functions

A bunch of routines return a pointer which is never Null but weren't
telling the compiler that such was the case.  A couple (strsubst(),
stripchars()) were accepting Null output argument and then returning
Null, but callers had no reason to use them that way, so they've been
changed.  (upstart() could have been changed similarly; I've already
forgotten why I left it as-is.)

src/hacklib.c

@@ -224,6 +224,7 @@ eos(char *s)
     return s;
 }
 
+/* version of eos() which takes a const* arg and returns that result */
 const char *
 c_eos(const char *s)
 {
@@ -519,22 +520,23 @@ visctrl(char c)
 /* caller is responsible for ensuring that bp is a
    valid pointer to a BUFSZ buffer */
 char *
-stripchars(char *bp, const char *stuff_to_strip, const char *orig)
+stripchars(
+    char *bp,
+    const char *stuff_to_strip,
+    const char *orig)
 {
     int i = 0;
     char *s = bp;
 
-    if (s) {
-        while (*orig && i < (BUFSZ - 1)) {
-            if (!strchr(stuff_to_strip, *orig)) {
-                *s++ = *orig;
-                i++;
-            }
-            orig++;
+    while (*orig && i < (BUFSZ - 1)) {
+        if (!strchr(stuff_to_strip, *orig)) {
+            *s++ = *orig;
+            i++;
         }
-        *s = '\0';
-    } else
-        impossible("no output buf in stripchars");
+        orig++;
+    }
+    *s = '\0';
+
     return bp;
 }
 
@@ -552,21 +554,22 @@ stripdigits(char *s)
     return s;
 }
 
-/* substitute a word or phrase in a string (in place) */
-/* caller is responsible for ensuring that bp points to big enough buffer */
+/* substitute a word or phrase in a string (in place);
+   caller is responsible for ensuring that bp points to big enough buffer */
 char *
-strsubst(char *bp, const char *orig, const char *replacement)
+strsubst(
+    char *bp,
+    const char *orig,
+    const char *replacement)
 {
     char *found, buf[BUFSZ];
+    /* [this could be replaced by strNsubst(bp, orig, replacement, 1)] */
 
-    if (bp) {
-        /* [this could be replaced by strNsubst(bp, orig, replacement, 1)] */
-        found = strstr(bp, orig);
-        if (found) {
-            Strcpy(buf, found + strlen(orig));
-            Strcpy(found, replacement);
-            Strcat(bp, buf);
-        }
+    found = strstr(bp, orig);
+    if (found) {
+        Strcpy(buf, found + strlen(orig));
+        Strcpy(found, replacement);
+        Strcat(bp, buf);
     }
     return bp;
 }
@@ -828,8 +831,9 @@ pmatchz(const char *patrn, const char *strng)
 /* case insensitive counted string comparison */
 /*{ aka strncasecmp }*/
 int
-strncmpi(const char *s1, const char *s2,
-         int n) /*(should probably be size_t, which is unsigned)*/
+strncmpi(
+    const char *s1, const char *s2,
+    int n) /*(should probably be size_t, which is unsigned)*/
 {
     char t1, t2;
 
@@ -895,8 +899,10 @@ strstri(const char *str, const char *sub)
 /* compare two strings for equality, ignoring the presence of specified
    characters (typically whitespace) and possibly ignoring case */
 boolean
-fuzzymatch(const char *s1, const char *s2, const char *ignore_chars,
-           boolean caseblind)
+fuzzymatch(
+    const char *s1, const char *s2,
+    const char *ignore_chars,
+    boolean caseblind)
 {
     char c1, c2;
 
@@ -1158,13 +1164,13 @@ time_from_yyyymmddhhmmss(char *buf)
             t.tm_sec = atoi(s);
             timeresult = mktime(&t);
         }
-        if (timeresult == (time_t) -1)
+        if (timeresult == (time_t) -1) {
             debugpline1("time_from_yyyymmddhhmmss(%s) would have returned -1",
                         buf ? buf : "");
-        else
-            return timeresult;
+            timeresult = (time_t) 0;
+        }
     }
-    return (time_t) 0;
+    return timeresult;
 }
 
 /*