src/common/compat/string.h

   1 /*
   2  * Copyright (C) 2015 Michael Jeanson <mjeanson@efficios.com>
   3  * Copyright (C) 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: MIT
   6  *
   7  */
   8
   9 #ifndef _COMPAT_STRING_H
  10 #define _COMPAT_STRING_H
  11
  12 #include <string.h>
  13
  14 #ifdef HAVE_STRNLEN
  15 static inline
  16 size_t lttng_strnlen(const char *str, size_t max)
  17 {
  18         return strnlen(str, max);
  19 }
  20 #else
  21 static inline
  22 size_t lttng_strnlen(const char *str, size_t max)
  23 {
  24         size_t ret;
  25         const char *end;
  26
  27         end = memchr(str, 0, max);
  28
  29         if (end) {
  30                 ret = (size_t) (end - str);
  31         } else {
  32                 ret = max;
  33         }
  34
  35         return ret;
  36 }
  37 #endif /* HAVE_STRNLEN */
  38
  39 #ifdef HAVE_STRNDUP
  40 static inline
  41 char *lttng_strndup(const char *s, size_t n)
  42 {
  43         return strndup(s, n);
  44 }
  45 #else
  46 static inline
  47 char *lttng_strndup(const char *s, size_t n)
  48 {
  49         char *ret;
  50         size_t navail;
  51
  52         if (!s) {
  53                 ret = NULL;
  54                 goto end;
  55         }
  56
  57         /* min() */
  58         navail = strlen(s) + 1;
  59         if ((n + 1) < navail) {
  60                 navail = n + 1;
  61         }
  62
  63         ret = malloc(navail);
  64         if (!ret) {
  65                 goto end;
  66         }
  67
  68         memcpy(ret, s, navail);
  69         ret[navail - 1] = '\0';
  70 end:
  71         return ret;
  72 }
  73 #endif /* HAVE_STRNDUP */
  74
  75 #ifdef HAVE_FLS
  76 static inline int lttng_fls(int val)
  77 {
  78         return fls(val);
  79 }
  80 #else
  81 static inline int lttng_fls(int val)
  82 {
  83         int r = 32;
  84         unsigned int x = (unsigned int) val;
  85
  86         if (!x)
  87                 return 0;
  88         if (!(x & 0xFFFF0000U)) {
  89                 x <<= 16;
  90                 r -= 16;
  91         }
  92         if (!(x & 0xFF000000U)) {
  93                 x <<= 8;
  94                 r -= 8;
  95         }
  96         if (!(x & 0xF0000000U)) {
  97                 x <<= 4;
  98                 r -= 4;
  99         }
 100         if (!(x & 0xC0000000U)) {
 101                 x <<= 2;
 102                 r -= 2;
 103         }
 104         if (!(x & 0x80000000U)) {
 105                 r -= 1;
 106         }
 107         return r;
 108 }
 109 #endif /* HAVE_FLS */
 110
 111 #if HAVE_MEMRCHR
 112 static inline
 113 void *lttng_memrchr(const void *s, int c, size_t n)
 114 {
 115         return memrchr(s, c, n);
 116 }
 117 #else
 118 static inline
 119 void *lttng_memrchr(const void *s, int c, size_t n)
 120 {
 121         int i;
 122         const char *str = s;
 123         for (i = n-1; i >= 0; i--) {
 124                 if (str[i] == (char)c) {
 125                         return (void *)(str+i);
 126                 }
 127         }
 128         return NULL;
 129 }
 130 #endif /* HAVE_MEMRCHR */
 131
 132 #endif /* _COMPAT_STRING_H */