common/util.h

   1 /*
   2  * util.h - useful functions header
   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 #ifndef AWESOME_COMMON_UTIL_H
  24 #define AWESOME_COMMON_UTIL_H
  25
  26 #define _GNU_SOURCE
  27
  28 #include <string.h>
  29 #include <stdlib.h>
  30 #include <stdbool.h>
  31 #include <stdarg.h>
  32 #include <assert.h>
  33 #include <stdio.h>
  34
  35 #if !(defined (__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__))
  36 #include <alloca.h>
  37 #endif
  38
  39 typedef enum
  40 {
  41     East = 0,
  42     South,
  43     North,
  44 } orientation_t;
  45
  46 /** A list of possible position, not sex related */
  47 typedef enum
  48 {
  49     Top = 0,
  50     Bottom,
  51     Right,
  52     Left
  53 } position_t;
  54
  55 /** \brief replace \c NULL strings with empty strings */
  56 #define NONULL(x)       (x ? x : "")
  57
  58 #define DO_NOTHING(...)
  59
  60 #undef MAX
  61 #undef MIN
  62 #define MAX(a,b) ((a) < (b) ? (b) : (a))
  63 #define MIN(a,b) ((a) < (b) ? (a) : (b))
  64
  65 #define unsigned_subtract(a, b)  \
  66     do {                         \
  67         if (b > a)               \
  68             a = 0;               \
  69         else                     \
  70             a -= b;              \
  71     } while (0)
  72
  73 #define ssizeof(foo)            (ssize_t)sizeof(foo)
  74 #define countof(foo)            (ssizeof(foo) / ssizeof(foo[0]))
  75 #define fieldsizeof(type_t, m)  sizeof(((type_t *)0)->m)
  76 #define fieldtypeof(type_t, m)  typeof(((type_t *)0)->m)
  77
  78 #define p_alloca(type, count)                                \
  79         ((type *)memset(alloca(sizeof(type) * (count)),      \
  80                         0, sizeof(type) * (count)))
  81
  82 #define p_alloc_nr(x)           (((x) + 16) * 3 / 2)
  83 #define p_new(type, count)      ((type *)xmalloc(sizeof(type) * (count)))
  84 #define p_clear(p, count)       ((void)memset((p), 0, sizeof(*(p)) * (count)))
  85 #define p_realloc(pp, count)    xrealloc((void*)(pp), sizeof(**(pp)) * (count))
  86 #define p_dup(p, count)         xmemdup((p), sizeof(*(p)) * (count))
  87 #define p_grow(pp, goalnb, allocnb)                  \
  88     do {                                             \
  89         if ((goalnb) > *(allocnb)) {                 \
  90             if (p_alloc_nr(*(allocnb)) < (goalnb)) { \
  91                 *(allocnb) = (goalnb);               \
  92             } else {                                 \
  93                 *(allocnb) = p_alloc_nr(*(allocnb)); \
  94             }                                        \
  95             p_realloc(pp, *(allocnb));               \
  96         }                                            \
  97     } while (0)
  98
  99
 100 #ifdef __GNUC__
 101
 102 #define p_delete(mem_pp)                           \
 103     do {                                           \
 104         typeof(**(mem_pp)) **__ptr = (mem_pp);     \
 105         free(*__ptr);                              \
 106         *__ptr = NULL;                             \
 107     } while(0)
 108
 109 #define likely(expr)    __builtin_expect(!!(expr), 1)
 110 #define unlikely(expr)  __builtin_expect((expr), 0)
 111
 112 #else
 113
 114 #define p_delete(mem_p)                            \
 115     do {                                           \
 116         void *__ptr = (mem_p);                     \
 117         free(*__ptr);                              \
 118         *(void **)__ptr = NULL;                    \
 119     } while (0)
 120
 121 #define likely(expr)    expr
 122 #define unlikely(expr)  expr
 123
 124 #endif
 125
 126 static inline void * __attribute__ ((malloc)) xmalloc(ssize_t size)
 127 {
 128     void *ptr;
 129
 130     if(size <= 0)
 131         return NULL;
 132
 133     ptr = calloc(1, size);
 134
 135     if(!ptr)
 136         abort();
 137
 138     return ptr;
 139 }
 140
 141 static inline void
 142 xrealloc(void **ptr, ssize_t newsize)
 143 {
 144     if(newsize <= 0)
 145         p_delete(ptr);
 146     else
 147     {
 148         *ptr = realloc(*ptr, newsize);
 149         if(!*ptr)
 150             abort();
 151     }
 152 }
 153
 154 /** Duplicate a memory zone.
 155  * \param src The source.
 156  * \param size The source size.
 157  * \return The memory address of the copy.
 158  */
 159 static inline void *xmemdup(const void *src, ssize_t size)
 160 {
 161     return memcpy(xmalloc(size), src, size);
 162 }
 163
 164 /** \brief \c NULL resistant strlen.
 165  *
 166  * Unlike it's libc sibling, a_strlen returns a ssize_t, and supports its
 167  * argument being NULL.
 168  *
 169  * \param[in] s the string.
 170  * \return the string length (or 0 if \c s is \c NULL).
 171  */
 172 static inline ssize_t a_strlen(const char *s)
 173 {
 174     return s ? strlen(s) : 0;
 175 }
 176
 177 /** \brief \c NULL resistant strnlen.
 178  *
 179  * Unlike it's GNU libc sibling, a_strnlen returns a ssize_t, and supports
 180  * its argument being NULL.
 181  *
 182  * The a_strnlen() function returns the number of characters in the string
 183  * pointed to by \c s, not including the terminating \c \\0 character, but at
 184  * most \c n. In doing this, a_strnlen() looks only at the first \c n
 185  * characters at \c s and never beyond \c s+n.
 186  *
 187  * \param[in]  s    the string.
 188  * \param[in]  n    the maximum length to return.
 189  * \return \c a_strlen(s) if less than \c n, else \c n.
 190  */
 191 static inline ssize_t a_strnlen(const char *s, ssize_t n)
 192 {
 193     if (s)
 194     {
 195         const char *p = memchr(s, '\0', n);
 196         return p ? p - s : n;
 197     }
 198     return 0;
 199 }
 200
 201 /** \brief \c NULL resistant strdup.
 202  *
 203  * The a_strdup() function returns a pointer to a new string, which is a
 204  * duplicate of \c s. Memory should be freed using p_delete().
 205  *
 206  * \warning when s is \c "", it returns NULL !
 207  *
 208  * \param[in] s the string to duplicate.
 209  * \return a pointer to the duplicated string.
 210  */
 211 static inline
 212 char *a_strdup(const char *s)
 213 {
 214     ssize_t len = a_strlen(s);
 215     return len ? p_dup(s, len + 1) : NULL;
 216 }
 217
 218 /** \brief safe limited strdup.
 219  *
 220  * Copies at most min(<tt>n-1</tt>, \c l) characters from \c src into a newly
 221  * allocated buffer, always adding a final \c \\0, and returns that buffer.
 222  *
 223  * \warning when s is \c "" or l is 0, it returns NULL !
 224  *
 225  * \param[in]  s        source string.
 226  * \param[in]  l        maximum number of chars to copy.
 227  * \return a newly allocated buffer containing the first \c l chars of \c src.
 228 */
 229 static inline
 230 char * a_strndup(const char *s, ssize_t l)
 231 {
 232     ssize_t len = MIN(a_strlen(s), l);
 233     if(len)
 234     {
 235         char *p = p_dup(s, len + 1);
 236         p[len] = '\0';
 237         return p;
 238     }
 239     return NULL;
 240 }
 241
 242 /** \brief \c NULL resistant strcmp.
 243  * \param[in]  a     the first string.
 244  * \param[in]  b     the second string.
 245  * \return <tt>strcmp(a, b)</tt>, and treats \c NULL strings like \c ""
 246  * ones.
 247  */
 248 static inline int a_strcmp(const char *a, const char *b)
 249 {
 250     return strcmp(NONULL(a), NONULL(b));
 251 }
 252
 253 /** \brief \c NULL resistant strcasecmp.
 254  * \param[in]  a     the first string.
 255  * \param[in]  b     the second string.
 256  * \return <tt>strcasecmp(a, b)</tt>, and treats \c NULL strings like \c ""
 257  * ones.
 258  */
 259 static inline int a_strcasecmp(const char *a, const char *b)
 260 {
 261     return strcasecmp(NONULL(a), NONULL(b));
 262 }
 263
 264 /** \brief \c NULL resistant strncmp.
 265  * \param[in]  a     the first string.
 266  * \param[in]  b     the second string.
 267  * \param[in]  n     the number of maximum chars to compare.
 268  * \return <tt>strncmp(a, b, n)</tt>, and treats \c NULL strings like \c ""
 269  * ones.
 270  */
 271 static inline int a_strncmp(const char *a, const char *b, ssize_t n)
 272 {
 273     return strncmp(NONULL(a), NONULL(b), n);
 274 }
 275
 276 ssize_t a_strncpy(char *dst, ssize_t n, const char *src, ssize_t l) __attribute__((nonnull(1)));
 277 ssize_t a_strcpy(char *dst, ssize_t n, const char *src) __attribute__((nonnull(1)));
 278
 279 /** \brief safe strcat.
 280  *
 281  * The a_strcat() function appends the string \c src at the end of the buffer
 282  * \c dst if space is available.
 283  *
 284  * \param[in]  dst   destination buffer.
 285  * \param[in]  n     size of the buffer, Negative sizes are allowed.
 286  * \param[in]  src   the string to append.
 287  * \return <tt>a_strlen(dst) + a_strlen(src)</tt>
 288  */
 289 static inline ssize_t a_strcat(char *dst, ssize_t n, const char *src)
 290 {
 291     ssize_t dlen = a_strnlen(dst, n - 1);
 292     return dlen + a_strcpy(dst + dlen, n - dlen, src);
 293 }
 294
 295 /** \brief safe strncat.
 296  *
 297  * The a_strncat() function appends at most \c n chars from the string \c src
 298  * at the end of the buffer \c dst if space is available.
 299  *
 300  * \param[in]  dst   destination buffer.
 301  * \param[in]  n     size of the buffer, Negative sizes are allowed.
 302  * \param[in]  src   the string to append.
 303  * \param[in]  l     maximum number of chars of src to consider.
 304  * \return the smallest value between <tt>a_strlen(dst) + a_strlen(src)</tt>
 305  * and <tt>a_strlen(dst) + l</tt>
 306  */
 307 static inline ssize_t
 308 a_strncat(char *dst, ssize_t n, const char *src, ssize_t l)
 309 {
 310     ssize_t dlen = a_strnlen(dst, n - 1);
 311     return dlen + a_strncpy(dst + dlen, n - dlen, src, l);
 312 }
 313
 314 /** Compute a hash for a string.
 315  * This is based on 'djb2' algorithm.
 316  */
 317 static inline unsigned long __attribute__ ((nonnull(1)))
 318 a_strhash(const unsigned char *str)
 319 {
 320     unsigned long hash = 5381;
 321     int c;
 322
 323     while((c = *str++))
 324         hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
 325
 326     return hash;
 327 }
 328
 329 #define fatal(string, ...) _fatal(__LINE__, \
 330                                   __FUNCTION__, \
 331                                   string, ## __VA_ARGS__)
 332 void _fatal(int, const char *, const char *, ...)
 333     __attribute__ ((noreturn)) __attribute__ ((format(printf, 3, 4)));
 334
 335 #define warn(string, ...) _warn(__LINE__, \
 336                                 __FUNCTION__, \
 337                                 string, ## __VA_ARGS__)
 338 void _warn(int, const char *, const char *, ...)
 339     __attribute__ ((format(printf, 3, 4)));
 340
 341 position_t position_fromstr(const char *, ssize_t);
 342 const char * position_tostr(position_t);
 343 orientation_t orientation_fromstr(const char *, ssize_t);
 344 const char * orientation_tostr(orientation_t);
 345 void a_exec(const char *);
 346
 347 #endif
 348 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80