git-compat-util: convert skip_{prefix,suffix}{,_mem} to bool

Use the data type bool and its values true and false to document the
binary return value of skip_prefix() and friends more explicitly.

This first use of stdbool.h, introduced with C99, is meant to check
whether there are platforms that claim support for C99, as tested by
7bc341e21b (git-compat-util: add a test balloon for C99 support,
2021-12-01), but still lack that header for some reason.

A fallback based on a wider type, e.g. int, would have to deal with
comparisons somehow to emulate that any non-zero value is true:

   bool b1 = 1;
   bool b2 = 2;
   if (b1 == b2) puts("This is true.");

   int i1 = 1;
   int i2 = 2;
   if (i1 == i2) puts("Not printed.");
   #define BOOLEQ(a, b) (!(a) == !(b))
   if (BOOLEQ(i1, i2)) puts("This is true.");

So we'd be better off using bool everywhere without a fallback, if
possible.  That's why this patch doesn't include any.

Signed-off-by: René Scharfe <l.s.r@web.de>
Acked-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-compat-util.h b/git-compat-util.h
index 3e7a59b5ff108dddce111cb372b6c846c093b4be..603c97e3b3f096adda2893af0dc2e5ab96af9f46 100644 (file)
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -225,6 +225,7 @@ struct strbuf;
 #include <stddef.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <string.h>
 #ifdef HAVE_STRINGS_H
 #include <strings.h> /* for strcasecmp() */
@@ -684,11 +685,11 @@ report_fn get_warn_routine(void);
 void set_die_is_recursing_routine(int (*routine)(void));
 
 /*
- * If the string "str" begins with the string found in "prefix", return 1.
+ * If the string "str" begins with the string found in "prefix", return true.
  * The "out" parameter is set to "str + strlen(prefix)" (i.e., to the point in
  * the string right after the prefix).
  *
- * Otherwise, return 0 and leave "out" untouched.
+ * Otherwise, return false and leave "out" untouched.
  *
  * Examples:
  *
@@ -699,57 +700,58 @@ void set_die_is_recursing_routine(int (*routine)(void));
  *   [skip prefix if present, otherwise use whole string]
  *   skip_prefix(name, "refs/heads/", &name);
  */
-static inline int skip_prefix(const char *str, const char *prefix,
-                             const char **out)
+static inline bool skip_prefix(const char *str, const char *prefix,
+                              const char **out)
 {
        do {
                if (!*prefix) {
                        *out = str;
-                       return 1;
+                       return true;
                }
        } while (*str++ == *prefix++);
-       return 0;
+       return false;
 }
 
 /*
  * Like skip_prefix, but promises never to read past "len" bytes of the input
  * buffer, and returns the remaining number of bytes in "out" via "outlen".
  */
-static inline int skip_prefix_mem(const char *buf, size_t len,
-                                 const char *prefix,
-                                 const char **out, size_t *outlen)
+static inline bool skip_prefix_mem(const char *buf, size_t len,
+                                  const char *prefix,
+                                  const char **out, size_t *outlen)
 {
        size_t prefix_len = strlen(prefix);
        if (prefix_len <= len && !memcmp(buf, prefix, prefix_len)) {
                *out = buf + prefix_len;
                *outlen = len - prefix_len;
-               return 1;
+               return true;
        }
-       return 0;
+       return false;
 }
 
 /*
- * If buf ends with suffix, return 1 and subtract the length of the suffix
- * from *len. Otherwise, return 0 and leave *len untouched.
+ * If buf ends with suffix, return true and subtract the length of the suffix
+ * from *len. Otherwise, return false and leave *len untouched.
  */
-static inline int strip_suffix_mem(const char *buf, size_t *len,
-                                  const char *suffix)
+static inline bool strip_suffix_mem(const char *buf, size_t *len,
+                                   const char *suffix)
 {
        size_t suflen = strlen(suffix);
        if (*len < suflen || memcmp(buf + (*len - suflen), suffix, suflen))
-               return 0;
+               return false;
        *len -= suflen;
-       return 1;
+       return true;
 }
 
 /*
- * If str ends with suffix, return 1 and set *len to the size of the string
- * without the suffix. Otherwise, return 0 and set *len to the size of the
+ * If str ends with suffix, return true and set *len to the size of the string
+ * without the suffix. Otherwise, return false and set *len to the size of the
  * string.
  *
  * Note that we do _not_ NUL-terminate str to the new length.
  */
-static inline int strip_suffix(const char *str, const char *suffix, size_t *len)
+static inline bool strip_suffix(const char *str, const char *suffix,
+                               size_t *len)
 {
        *len = strlen(str);
        return strip_suffix_mem(str, len, suffix);