src/: Simplify, using strpbrk(3)

[alejandro-colomar]

Checking a boolean (actually, a boolean-like pointer) is more readable
than comparing against a length.

This removes the only uses of strcspn(3) in this project.

strpbrk(3) is a simpler call, even though it has a weird name.  It's
just like strchr(3) but searches for several characters.  I'd have named
it strchrs().

---

@hallyn Oh well, this is your fault for mentioning that. :D

---

Revisions:

v2

• Since strpbrk(3) is like strchr(3), use it similarly. That is, treat it as a boolean, with the meaning "the characters were found". Act as if it was called strchrs().

• Use spaces instead of tabs.

$ git range-diff shadow/master gh/strpbrk strpbrk 
1:  878792c7 ! 1:  72823449 src/: Simplify, using strpbrk(3)
    @@ Metadata
      ## Commit message ##
         src/: Simplify, using strpbrk(3)
     
    -    Comparing against NULL is more readable than comparing against a length.
    +    Checking a boolean (actually, a boolean-like pointer) is more readable
    +    than comparing against a length.
     
    -    This removes the only uses of strcspn(3) in this project.  strpbrk(3) is
    -    a simpler call, even though it has a weird name.  It's just like
    -    strchr(3) but searches for several characters.  I'd have named it
    -    strchrs().
    +    This removes the only uses of strcspn(3) in this project.
    +
    +    strpbrk(3) is a simpler call, even though it has a weird name.  It's
    +    just like strchr(3) but searches for several characters.  I'd have named
    +    it strchrs().
     
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
    @@ src/useradd.c: static const char *def_log_init = "yes";
      static const char *def_expire = "";
      
     -#define   VALID(s)        (strcspn (s, ":\n") == strlen (s))
    -+#define   VALID(s)        (strpbrk(s, ":\n") == NULL)
    ++#define VALID(s)  (!strpbrk(s, ":\n"))
      
      static const char *user_name = "";
      static const char *user_pass = "!";
    @@ src/usermod.c
      #endif                            /* ENABLE_SUBIDS */
      
     -#define   VALID(s)        (strcspn (s, ":\n") == strlen (s))
    -+#define   VALID(s)        (strpbrk(s, ":\n") == NULL)
    ++#define VALID(s)  (!strpbrk(s, ":\n"))
      
      /*
       * Global variables

v3

• Treat strpbrk(3) as a boolean everywhere.

$ git range-diff shadow/master gh/strpbrk strpbrk 
1:  72823449 = 1:  72823449 src/: Simplify, using strpbrk(3)
-:  -------- > 2:  258e9e29 lib/: Treat strpbrk(3)'s return value as a boolean

v3b

• Rebase

$ git range-diff 4.17.1..gh/strpbrk master..strpbrk 
1:  72823449 = 1:  44e9c6ac src/: Simplify, using strpbrk(3)
2:  258e9e29 = 2:  c534aa67 lib/: Treat strpbrk(3)'s return value as a boolean

v3c

• Rebase

$ git range-diff master..gh/strpbrk shadow/master..strpbrk 
1:  f6b53605 = 1:  8a3145a2 src/: Simplify, using strpbrk(3)
2:  e7a56050 = 2:  412d4daf lib/: Treat strpbrk(3)'s return value as a boolean

[alejandro-colomar]

BTW, 9front actually calls this function strchrs() instead of strpbrk(3). :)

https://github.com/9front/9front/blob/71ca9a668a27dfd215c48091aa6290f6f0416a14/sys/src/cmd/ip/cifsd/util.c#L205