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