mdw@git.distorted.org.uk Git - mLib/blob - utils/macros.h

   1 /* -*-c-*-
   2  *
   3  * Handy macros
   4  *
   5  * (c) 2003 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 #ifndef MLIB_MACROS_H
  29 #define MLIB_MACROS_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #include <assert.h>
  38
  39 #ifndef MLIB_COMPILER_H
  40 #  include "compiler.h"
  41 #endif
  42
  43 /*----- Miscellaneous utility macros --------------------------------------*/
  44
  45 #define N(v) (sizeof(v)/sizeof(*(v)))
  46
  47 #define MLIB__STR(x) #x
  48 #define STR(x) MLIB__STR(x)
  49
  50 #define MLIB__GLUE(x, y) x##y
  51 #define GLUE(x, y) MLIB__GLUE(x, y)
  52
  53 #ifdef static_assert
  54 #  define STATIC_ASSERT(cond, msg) static_assert(!!(cond), msg)
  55 #else
  56 #  define STATIC_ASSERT(cond, msg)                                      \
  57         IGNORABLE extern char static_assert_failed[2*!!(cond) - 1]
  58 #endif
  59
  60 #define COMMA ,
  61
  62 /*----- String and character hacks ----------------------------------------*/
  63
  64 #define CTYPE_HACK(func, ch) (func((unsigned char)(ch)))
  65
  66 #define ISALNUM(ch) CTYPE_HACK(isalnum, ch)
  67 #define ISALPHA(ch) CTYPE_HACK(isalpha, ch)
  68 #define ISASCII(ch) CTYPE_HACK(isascii, ch)
  69 #define ISBLANK(ch) CTYPE_HACK(isblank, ch)
  70 #define ISCNTRL(ch) CTYPE_HACK(iscntrl, ch)
  71 #define ISDIGIT(ch) CTYPE_HACK(isdigit, ch)
  72 #define ISGRAPH(ch) CTYPE_HACK(isgraph, ch)
  73 #define ISLOWER(ch) CTYPE_HACK(islower, ch)
  74 #define ISPRINT(ch) CTYPE_HACK(isprint, ch)
  75 #define ISPUNCT(ch) CTYPE_HACK(ispunct, ch)
  76 #define ISSPACE(ch) CTYPE_HACK(isspace, ch)
  77 #define ISUPPER(ch) CTYPE_HACK(isupper, ch)
  78 #define ISXDIGIT(ch) CTYPE_HACK(isxdigit, ch)
  79
  80 #define TOASCII(ch) CTYPE_HACK(toascii, ch)
  81 #define TOLOWER(ch) CTYPE_HACK(tolower, ch)
  82 #define TOUPPER(ch) CTYPE_HACK(toupper, ch)
  83
  84 #define MEMCMP(x, op, y, n) (memcmp((x), (y), (n)) op 0)
  85 #define STRCMP(x, op, y) (strcmp((x), (y)) op 0)
  86 #define STRNCMP(x, op, y, n) (strncmp((x), (y), (n)) op 0)
  87
  88 /*----- Compiler diagnostics ----------------------------------------------*/
  89
  90 /* --- Compiler-specific definitions --- */
  91
  92 #if GCC_VERSION_P(2, 5) || CLANG_VERSION_P(3, 3)
  93 #  define NORETURN __attribute__((__noreturn__))
  94 #  define PRINTF_LIKE(fix, aix) __attribute__((__format__(printf, fix, aix)))
  95 #  define SCANF_LIKE(fix, aix) __attribute__((__format__(scanf, fix, aix)))
  96 #  define IGNORABLE __attribute__((__unused__))
  97 #endif
  98
  99 #if GCC_VERSION_P(3, 4) || CLANG_VERSION_P(3, 3)
 100 #  define MUST_CHECK __attribute__((__warn_unused_result__))
 101 #endif
 102
 103 #if GCC_VERSION_P(4, 5) || CLANG_VERSION_P(3, 3)
 104 #  define DEPRECATED(msg) __attribute__((__deprecated__(msg)))
 105 #elif GCC_VERSION_P(3, 1)
 106 #  define DEPRECATED(msg) __attribute__((__deprecated__))
 107 #endif
 108
 109 #if GCC_VERSION_P(4, 0) || CLANG_VERSION_P(3, 3)
 110 #  define EXECL_LIKE(ntrail) __attribute__((__sentinel__(ntrail)))
 111 #endif
 112
 113 #if GCC_VERSION_P(2, 7) || CLANG_VERSION_P(0, 0)
 114 #  define LAUNDER(x)                                                    \
 115         ({ __typeof__(x) _y; __asm__("" : "=g"(_y) : "0"(x)); _y; })
 116 #  define RELAX do __asm__ __volatile__("" ::: "memory"); while (0)
 117 #endif
 118
 119 #if CLANG_VERSION_P(3, 3)
 120
 121 #  define MLIB__PRAGMA_HACK(x) _Pragma(#x)
 122 #  define MLIB__MUFFLE_WARNINGS(warns, body)                            \
 123         _Pragma("clang diagnostic push")                                \
 124         warns                                                           \
 125         body                                                            \
 126         _Pragma("clang diagnostic pop")
 127 #  define CLANG_WARNING(warn)                                           \
 128         MLIB__PRAGMA_HACK(clang diagnostic ignored warn)
 129 #  define MUFFLE_WARNINGS_DECL(warns, body)                             \
 130         MLIB__MUFFLE_WARNINGS(warns, body)
 131 #  define MUFFLE_WARNINGS_EXPR(warns, body)                             \
 132         __extension__ ({ MLIB__MUFFLE_WARNINGS(warns, (body);) })
 133 #  define MUFFLE_WARNINGS_STMT(warns, body)                             \
 134         do { MLIB__MUFFLE_WARNINGS(warns, body) } while (0)
 135
 136 #endif
 137
 138 #if GCC_VERSION_P(4, 6)
 139
 140    /* --- Diagnostic suppression in GCC: a tale of woe --- *
 141     *
 142     * This is extremely unpleasant, largely as a result of bugs in the GCC
 143     * preprocessor's handling of @_Pragma@.  The fundamental problem is
 144     * that it's the preprocessor, and not the compiler proper, which
 145     * detects @_Pragma@, emitting @#pragma@ lines into its output; and it
 146     * does it during macro expansion, even if the macro is being expanded
 147     * during argument collection.  Since arguments are expanded before
 148     * replacing the macro's invocation with its body, a pragma in an
 149     * argument will be emitted %%\emph{before}%% any pragmata in the body,
 150     * even if they appear before the argument in the body -- and even if
 151     * the argument doesn't actually appear anywhere at all in the body.
 152     *
 153     * Another, rather less significant, problem is that @_Pragma@'s
 154     * argument is a single string literal, recognized in translation phase
 155     * 4, before string-literal concatenation in phase 6, so we must build
 156     * pragma bodies as token lists and then stringify them.
 157     *
 158     * As a result, we need some subterfuge here.  The @MLIB__PRAGMA_HACK@
 159     * macro issues a @_Pragma@ on its argument token list, which it
 160     * stringifies; this deals with the second problem.  The first is
 161     * trickier: we must delay expansion of @MLIB__PRAGMA_HACK@ from the
 162     * argument collection phase to the body rescanning phase, and we do
 163     * this by splitting the invocations between @GCC_WARNING@ macro calls:
 164     * the name is left hanging from the previous call (or from
 165     * @MLIB__MUFFLE_WARNINGS@, in the first case) and the body is supplied
 166     * by @GCC_WARNING@, which also supplies the next @MLIB__PRAGMA_HACK@.
 167     * The remaining problem is to make sure we can dispose of the final
 168     * trailing @MLIB__PRAGMA_HACK@ harmlessly, which we do by introducing
 169     * an extra argument @emitp@, which may be either @t@ or @nil@; this
 170     * dispatches to an appropriate helper macro by means of token-pasting.
 171     *
 172     * I'm so sorry.
 173     */
 174
 175 #  define MLIB__PRAGMA_HACK_t(x) _Pragma(#x)
 176 #  define MLIB__PRAGMA_HACK_nil(x)
 177 #  define MLIB__PRAGMA_HACK(emitp, x) MLIB__PRAGMA_HACK_##emitp(x)
 178 #  define MLIB__MUFFLE_WARNINGS(warns, body)                            \
 179         _Pragma("GCC diagnostic push") MLIB__PRAGMA_HACK                \
 180         warns                                                           \
 181         (nil, nil)                                                      \
 182         body                                                            \
 183         _Pragma("GCC diagnostic pop")
 184 #  define GCC_WARNING(warn)                                             \
 185         (t, GCC diagnostic ignored warn) MLIB__PRAGMA_HACK
 186 #  define MUFFLE_WARNINGS_DECL(warns, body)                             \
 187         MLIB__MUFFLE_WARNINGS(warns, body)
 188 #  define MUFFLE_WARNINGS_EXPR(warns, body)                             \
 189         __extension__ ({ MLIB__MUFFLE_WARNINGS(warns, (body);) })
 190 #  define MUFFLE_WARNINGS_STMT(warns, body)                             \
 191         do { MLIB__MUFFLE_WARNINGS(warns, body) } while (0)
 192 #endif
 193
 194 /* --- Fallback definitions, mostly trivial --- */
 195
 196 #ifndef DEPRECATED
 197 #  define DEPRECATED(msg)
 198 #endif
 199
 200 #ifndef EXECL_LIKE
 201 #  define EXECL_LIKE(ntrail)
 202 #endif
 203
 204 #ifndef DISCARD
 205 #  define DISCARD(x) do if (x); while (0)
 206 #endif
 207
 208 #ifndef IGNORE
 209 #  define IGNORE(x) ((void)(x))
 210 #endif
 211
 212 #ifndef MUFFLE_WARNINGS_DECL
 213 #  define MUFFLE_WARNINGS_DECL(warns, body) body
 214 #endif
 215
 216 #ifndef MUFFLE_WARNINGS_EXPR
 217 #  define MUFFLE_WARNINGS_EXPR(warns, body) (body)
 218 #endif
 219
 220 #ifndef MUFFLE_WARNINGS_STMT
 221 #  define MUFFLE_WARNINGS_STMT(warns, body) do { body } while (0)
 222 #endif
 223
 224 #ifndef PRINTF_LIKE
 225 #  define PRINF_LIKE(fmtix, argix)
 226 #endif
 227
 228 #ifndef SCANF_LIKE
 229 #  define SCANF_LIKE(fmtix, argix)
 230 #endif
 231
 232 #ifndef NORETURN
 233 #  define NORETURN
 234 #endif
 235
 236 #ifndef IGNORABLE
 237 #  define IGNORABLE
 238 #endif
 239
 240 #ifndef MUST_CHECK
 241 #  define MUST_CHECK
 242 #endif
 243
 244 #ifndef LAUNDER
 245 #  define LAUNDER
 246 #endif
 247
 248 #ifndef RELAX
 249 #  define RELAX
 250 #endif
 251
 252 #ifndef GCC_WARNING
 253 #  define GCC_WARNING(warn)
 254 #endif
 255
 256 #ifndef CLANG_WARNING
 257 #  define CLANG_WARNING(warn)
 258 #endif
 259
 260 /*----- That's all, folks -------------------------------------------------*/
 261
 262 #ifdef __cplusplus
 263   }
 264 #endif
 265
 266 #endif