src/common/compat/string.h

   1 /*
   2  * Copyright (C) 2015 Michael Jeanson <mjeanson@efficios.com>
   3  *               2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a copy
   6  * of this software and associated documentation files (the "Software"), to deal
   7  * in the Software without restriction, including without limitation the rights
   8  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9  * copies of the Software, and to permit persons to whom the Software is
  10  * furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be included in
  13  * all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #ifndef _COMPAT_STRING_H
  25 #define _COMPAT_STRING_H
  26
  27 #include <string.h>
  28 #include <stdlib.h>
  29
  30 #ifdef HAVE_STRNLEN
  31 static inline
  32 size_t lttng_strnlen(const char *str, size_t max)
  33 {
  34         return strnlen(str, max);
  35 }
  36 #else
  37 static inline
  38 size_t lttng_strnlen(const char *str, size_t max)
  39 {
  40         size_t ret;
  41         const char *end;
  42
  43         end = memchr(str, 0, max);
  44
  45         if (end) {
  46                 ret = (size_t) (end - str);
  47         } else {
  48                 ret = max;
  49         }
  50
  51         return ret;
  52 }
  53 #endif /* HAVE_STRNLEN */
  54
  55 #ifdef HAVE_STRNDUP
  56 static inline
  57 char *lttng_strndup(const char *s, size_t n)
  58 {
  59         return strndup(s, n);
  60 }
  61 #else
  62 static inline
  63 char *lttng_strndup(const char *s, size_t n)
  64 {
  65         char *ret;
  66         size_t navail;
  67
  68         if (!s) {
  69                 ret = NULL;
  70                 goto end;
  71         }
  72
  73         /* min() */
  74         navail = strlen(s) + 1;
  75         if ((n + 1) < navail) {
  76                 navail = n + 1;
  77         }
  78
  79         ret = malloc(navail);
  80         if (!ret) {
  81                 goto end;
  82         }
  83
  84         memcpy(ret, s, navail);
  85         ret[navail - 1] = '\0';
  86 end:
  87         return ret;
  88 }
  89 #endif /* HAVE_STRNDUP */
  90
  91 #ifdef HAVE_FLS
  92 static inline int lttng_fls(int val)
  93 {
  94         return fls(val);
  95 }
  96 #else
  97 static inline int lttng_fls(int val)
  98 {
  99         int r = 32;
 100         unsigned int x = (unsigned int) val;
 101
 102         if (!x)
 103                 return 0;
 104         if (!(x & 0xFFFF0000U)) {
 105                 x <<= 16;
 106                 r -= 16;
 107         }
 108         if (!(x & 0xFF000000U)) {
 109                 x <<= 8;
 110                 r -= 8;
 111         }
 112         if (!(x & 0xF0000000U)) {
 113                 x <<= 4;
 114                 r -= 4;
 115         }
 116         if (!(x & 0xC0000000U)) {
 117                 x <<= 2;
 118                 r -= 2;
 119         }
 120         if (!(x & 0x80000000U)) {
 121                 r -= 1;
 122         }
 123         return r;
 124 }
 125 #endif /* HAVE_FLS */
 126
 127 #if HAVE_MEMRCHR
 128 static inline
 129 void *lttng_memrchr(const void *s, int c, size_t n)
 130 {
 131         return memrchr(s, c, n);
 132 }
 133 #else
 134 static inline
 135 void *lttng_memrchr(const void *s, int c, size_t n)
 136 {
 137         int i;
 138         const char *str = s;
 139         for (i = n-1; i >= 0; i--) {
 140                 if (str[i] == (char)c) {
 141                         return (void *)(str+i);
 142                 }
 143         }
 144         return NULL;
 145 }
 146 #endif /* HAVE_MEMRCHR */
 147
 148 #endif /* _COMPAT_STRING_H */