util.h

   1 #ifndef UTIL_H
   2 #define UTIL_H
   3
   4 #include <stdint.h>
   5 #include <stdbool.h>
   6
   7 #define LENGTH(x)  ((int)(sizeof (x) / sizeof *(x)))
   8 #define MIN(a, b)  ((a) > (b) ? (b) : (a))
   9 #define MAX(a, b)  ((a) < (b) ? (b) : (a))
  10
  11 /* is c the start of a utf8 sequence? */
  12 #define ISUTF8(c)   (((c)&0xC0)!=0x80)
  13 #define ISASCII(ch) ((unsigned char)ch < 0x80)
  14
  15 #if GCC_VERSION>=5004000 || CLANG_VERSION>=4000000
  16 #define addu __builtin_add_overflow
  17 #else
  18 static inline bool addu(size_t a, size_t b, size_t *c) {
  19         if (SIZE_MAX - a < b)
  20                 return false;
  21         *c = a + b;
  22         return true;
  23 }
  24 #endif
  25
  26 #if !HAVE_MEMRCHR
  27 /* MIT licensed implementation from musl libc */
  28 static void *memrchr(const void *m, int c, size_t n)
  29 {
  30         const unsigned char *s = m;
  31         c = (unsigned char)c;
  32         while (n--) if (s[n]==c) return (void *)(s+n);
  33         return 0;
  34 }
  35 #endif
  36
  37 #endif /* UTIL_H */