A few more ptrlen functions.

ptrlen_contains and ptrlen_contains_only are useful for checking that
a string is composed entirely of certain characters, or avoids them.

ptrlen_end makes a pointer to the byte just past the end of the
specified string. And it can be used with make_ptrlen_startend, which
makes a ptrlen out of two pointers instead of a pointer and a length.

misc.h

@@ -169,6 +169,21 @@ static inline ptrlen make_ptrlen(const void *ptr, size_t len)
     return pl;
 }
 
+static inline const void *ptrlen_end(ptrlen pl)
+{
+    return (const char *)pl.ptr + pl.len;
+}
+
+static inline ptrlen make_ptrlen_startend(const void *startv, const void *endv)
+{
+    const char *start = (const char *)startv, *end = (const char *)endv;
+    assert(end >= start);
+    ptrlen pl;
+    pl.ptr = start;
+    pl.len = end - start;
+    return pl;
+}
+
 static inline ptrlen ptrlen_from_asciz(const char *str)
 {
     return make_ptrlen(str, strlen(str));
@@ -190,6 +205,8 @@ int ptrlen_strcmp(ptrlen pl1, ptrlen pl2);
 bool ptrlen_startswith(ptrlen whole, ptrlen prefix, ptrlen *tail);
 bool ptrlen_endswith(ptrlen whole, ptrlen suffix, ptrlen *tail);
 ptrlen ptrlen_get_word(ptrlen *input, const char *separators);
+bool ptrlen_contains(ptrlen input, const char *characters);
+bool ptrlen_contains_only(ptrlen input, const char *characters);
 char *mkstr(ptrlen pl);
 int string_length_for_printf(size_t);
 /* Derive two printf arguments from a ptrlen, suitable for "%.*s" */

utils/ptrlen.c

@@ -54,6 +54,22 @@ bool ptrlen_endswith(ptrlen whole, ptrlen suffix, ptrlen *tail)
     return false;
 }
 
+bool ptrlen_contains(ptrlen input, const char *characters)
+{
+    for (const char *p = input.ptr, *end = p + input.len; p < end; p++)
+        if (strchr(characters, *p))
+            return true;
+    return false;
+}
+
+bool ptrlen_contains_only(ptrlen input, const char *characters)
+{
+    for (const char *p = input.ptr, *end = p + input.len; p < end; p++)
+        if (!strchr(characters, *p))
+            return false;
+    return true;
+}
+
 ptrlen ptrlen_get_word(ptrlen *input, const char *separators)
 {
     const char *p = input->ptr, *end = p + input->len;