common/util.c

   1 /*
   2  * util.c - useful functions
   3  *
   4  * Copyright © 2007-2008 Julien Danjou <julien@danjou.info>
   5  * Copyright © 2006 Pierre Habouzit <madcoder@debian.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  */
  22
  23 #include <stdarg.h>
  24 #include <stdio.h>
  25 #include <sys/wait.h>
  26 #include <unistd.h>
  27 #include <limits.h>
  28
  29 #include "util.h"
  30
  31 /** Print error and exit
  32  * with EXIT_FAILURE code
  33  */
  34 void
  35 eprint(const char *fmt, ...)
  36 {
  37     va_list ap;
  38
  39     va_start(ap, fmt);
  40     fprintf(stderr, "awesome: ");
  41     vfprintf(stderr, fmt, ap);
  42     va_end(ap);
  43     exit(EXIT_FAILURE);
  44 }
  45
  46 /** Print error message
  47  * on stderr
  48  */
  49 void
  50 warn(const char *fmt, ...)
  51 {
  52     va_list ap;
  53     va_start(ap, fmt);
  54     fprintf(stderr, "awesome: ");
  55     vfprintf(stderr, fmt, ap);
  56     va_end(ap);
  57 }
  58
  59 /** Compute a value from a string containing
  60  * an absolute or a relative number. If relative,
  61  * add it to current_value.
  62  * \param arg the string with the number
  63  * \param current_value value to add the number if it's relative
  64  * \return new value
  65  */
  66 double
  67 compute_new_value_from_arg(const char *arg, double current_value)
  68 {
  69     double delta;
  70
  71     if(arg && sscanf(arg, "%lf", &delta) == 1)
  72     {
  73         if(arg[0] == '+' || arg[0] == '-')
  74             current_value += delta;
  75         else
  76             current_value = delta;
  77     }
  78
  79     return current_value;
  80 }
  81
  82 /** Lookup for a function pointer from its name
  83  * in the given name_func_link_t list
  84  * \param funcname Function name
  85  * \param list Function and name link list
  86  * \return function pointer
  87  */
  88 void *
  89 name_func_lookup(const char *funcname, const name_func_link_t *list)
  90 {
  91     int i;
  92
  93     if(funcname && list)
  94         for(i = 0; list[i].name; i++)
  95             if(!a_strcmp(funcname, list[i].name))
  96                 return list[i].func;
  97
  98     return NULL;
  99 }
 100
 101 /** \brief safe limited strcpy.
 102  *
 103  * Copies at most min(<tt>n-1</tt>, \c l) characters from \c src into \c dst,
 104  * always adding a final \c \\0 in \c dst.
 105  *
 106  * \param[in]  dst      destination buffer.
 107  * \param[in]  n        size of the buffer. Negative sizes are allowed.
 108  * \param[in]  src      source string.
 109  * \param[in]  l        maximum number of chars to copy.
 110  *
 111  * \return minimum of  \c src \e length and \c l.
 112 */
 113 ssize_t a_strncpy(char *dst, ssize_t n, const char *src, ssize_t l)
 114 {
 115     ssize_t len = MIN(a_strlen(src), l);
 116
 117     if (n > 0)
 118     {
 119         ssize_t dlen = MIN(n - 1, len);
 120         memcpy(dst, src, dlen);
 121         dst[dlen] = '\0';
 122     }
 123
 124     return len;
 125 }
 126
 127 /** \brief safe strcpy.
 128  *
 129  * Copies at most <tt>n-1</tt> characters from \c src into \c dst, always
 130  * adding a final \c \\0 in \c dst.
 131  *
 132  * \param[in]  dst      destination buffer.
 133  * \param[in]  n        size of the buffer. Negative sizes are allowed.
 134  * \param[in]  src      source string.
 135  * \return \c src \e length. If this value is \>= \c n then the copy was
 136  *         truncated.
 137  */
 138 ssize_t a_strcpy(char *dst, ssize_t n, const char *src)
 139 {
 140     ssize_t len = a_strlen(src);
 141
 142     if (n > 0)
 143     {
 144         ssize_t dlen = MIN(n - 1, len);
 145         memcpy(dst, src, dlen);
 146         dst[dlen] = '\0';
 147     }
 148
 149     return len;
 150 }
 151 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=80