src/common/compat/string.hpp

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