memory: xstrchrnul and xmemscan.

src/nvim/memory.c

@@ -222,6 +222,35 @@ void *xmemdupz(const void *data, size_t len)
   return memcpy(xmallocz(len), data, len);
 }
 
+/// A version of strchr() that returns a pointer to the terminating NUL if it
+/// doesn't find `c`.
+///
+/// @param str The string to search.
+/// @param c   The char to look for.
+/// @returns a pointer to the first instance of `c`, or to the NUL terminator
+///          if not found.
+char *xstrchrnul(const char *str, char c)
+  FUNC_ATTR_NONNULL_RET FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE
+{
+  char *p = strchr(str, c);
+  return p ? p : (char *)(str + strlen(str));
+}
+
+/// A version of memchr() that returns a pointer one past the end
+/// if it doesn't find `c`.
+///
+/// @param addr The address of the memory object.
+/// @param c    The char to look for.
+/// @param size The size of the memory object.
+/// @returns a pointer to the first instance of `c`, or one past the end if not
+///          found.
+void *xmemscan(const void *addr, char c, size_t size)
+  FUNC_ATTR_NONNULL_RET FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE
+{
+  char *p = memchr(addr, c, size);
+  return p ? p : (char *)addr + size;
+}
+
 /// The xstpcpy() function shall copy the string pointed to by src (including
 /// the terminating NUL character) into the array pointed to by dst.
 ///

src/nvim/message.c

@@ -3173,8 +3173,7 @@ int vim_vsnprintf(char *str, size_t str_m, char *fmt, va_list ap, typval_T *tvs)
     p = "";
   while (*p != NUL) {
     if (*p != '%') {
-      char    *q = strchr(p + 1, '%');
-      size_t n = (q == NULL) ? STRLEN(p) : (size_t)(q - p);
+      size_t n = xstrchrnul(p + 1, '%') - p;
 
       /* Copy up to the next '%' or NUL without any changes. */
       if (str_l < str_m) {

src/nvim/ops.c

@@ -4903,10 +4903,9 @@ static void str_to_reg(struct yankreg *y_ptr,
    * Find the end of each line and save it into the array.
    */
   for (start = 0; start < len + extraline; start += i + 1) {
-    for (i = start; i < len; ++i)       /* find the end of the line */
-      if (str[i] == '\n')
-        break;
-    i -= start;                         /* i is now length of line */
+    // Let i represent the length of one line.
+    const char_u *p = str + start;
+    i = (char_u *)xmemscan(p, '\n', len - start) - p;
     if (i > maxlen)
       maxlen = i;
     if (append) {

src/nvim/os/fs.c

@@ -134,10 +134,7 @@ static bool is_executable_in_path(const char_u *name, char_u **abspath)
   // Walk through all entries in $PATH to check if "name" exists there and
   // is an executable file.
   for (;; ) {
-    const char *e = strchr(path, ':');
-    if (e == NULL) {
-      e = path + STRLEN(path);
-    }
+    const char *e = xstrchrnul(path, ':');
 
     // Glue together the given directory from $PATH with name and save into
     // buf.