-/*----- Compiler diagnostics ----------------------------------------------*/
-
-/* --- Compiler-specific definitions --- */
-
-#if defined(__GNUC__)
-
-# define GCC_VERSION_P(maj, min) \
- (__GNUC__ > (maj) || (__GNUC__ == (maj) && __GNUC_MINOR__ >= (min)))
-
-# if GCC_VERSION_P(2, 5)
-# define NORETURN __attribute__((noreturn))
-# define PRINTF_LIKE(fix, aix) __attribute__((format(printf, fix, aix)))
-# define SCANF_LIKE(fix, aix) __attribute__((format(scanf, fix, aix)))
-# define IGNORABLE __attribute__((unused))
-# endif
-
-# if GCC_VERSION_P(4, 5)
-# define DEPRECATED(msg) __attribute__((deprecated(msg)))
-# elif GCC_VERSION_P(3, 1)
-# define DEPRECATED(msg) __attribute__((deprecated))
-# endif
-
-# if GCC_VERSION_P(4, 0)
-# define EXECL_LIKE(ntrail) __attribute__((sentinel(ntrail)))
-# endif
-
-# if GCC_VERSION_P(4, 6)
-
- /* --- Diagnostic suppression in GCC: a tale of woe --- *
- *
- * This is extremely unpleasant, largely as a result of bugs in the GCC
- * preprocessor's handling of @_Pragma@. The fundamental problem is
- * that it's the preprocessor, and not the compiler proper, which
- * detects @_Pragma@, emitting @#pragma@ lines into its output; and it
- * does it during macro expansion, even if the macro is being expanded
- * during argument collection. Since arguments are expanded before
- * replacing the macro's invocation with its body, a pragma in an
- * argument will be emitted %%\emph{before}%% any pragmata in the body,
- * even if they appear before the argument in the body -- and even if
- * the argument doesn't actually appear anywhere at all in the body.
- *
- * Another, rather less significant, problem is that @_Pragma@'s
- * argument is a single string literal, recognized in translation phase
- * 4, before string-literal concatenation in phase 6, so we must build
- * pragma bodies as token lists and then stringify them.
- *
- * As a result, we need some subterfuge here. The @MLIB__PRAGMA_HACK@
- * macro issues a @_Pragma@ on its argument token list, which it
- * stringifies; this deals with the second problem. The first is
- * trickier: we must delay expansion of @MLIB__PRAGMA_HACK@ from the
- * argument collection phase to the body rescanning phase, and we do
- * this by splitting the invocations between @GCC_WARNING@ macro calls:
- * the name is left hanging from the previous call (or from
- * @MLIB__MUFFLE_WARNINGS@, in the first case) and the body is supplied
- * by @GCC_WARNING@, which also supplies the next @MLIB__PRAGMA_HACK@.
- * The remaining problem is to make sure we can dispose of the final
- * trailing @MLIB__PRAGMA_HACK@ harmlessly, which we do by introducing
- * an extra argument @emitp@, which may be either @t@ or @nil@; this
- * dispatches to an appropriate helper macro by means of token-pasting.
- *
- * I'm so sorry.
- */
-
-# define MLIB__PRAGMA_HACK_t(x) _Pragma(#x)
-# define MLIB__PRAGMA_HACK_nil(x)
-# define MLIB__PRAGMA_HACK(emitp, x) MLIB__PRAGMA_HACK_##emitp(x)
-# define MLIB__MUFFLE_WARNINGS(warns, body) \
+/* --- @CHECK_TYPE@ ---
+ *
+ * Arguments: @expty@ = expected type of @x@
+ * @expty x@ = some object
+ *
+ * Returns: Integer zero.
+ *
+ * Use: Cause a compile-time failure unless the type of @x@ is
+ * assignment-compatible with @expty@.
+ */
+
+#define CHECK_TYPE(expty, x) (!sizeof(*(expty *)0 = (x)))
+
+/* --- @CONVERT_CAREFULLY@ ---
+ *
+ * Arguments: @newty@ = new type for the result
+ * @expty@ = expected type of @x@
+ * @expty x@ = some object
+ *
+ * Returns: @x@, but coerced to type @newty@.
+ *
+ * Use: Like @(newty)x@, except that it checks at compile-time that
+ * @x@ is at least assignment-compatible with type @expty@
+ * before trying.
+ */
+
+#define CONVERT_CAREFULLY(newty, expty, x) \
+ (CHECK_TYPE(expty, x) + (/*unconst unvolatile*/ newty)(x))
+
+/* --- @UNCONST@, @UNVOLATILE@, @UNQUALIFY@ --- *
+ *
+ * Arguments: @type@ = a type name
+ * @type *p@ = a pointer
+ *
+ * Returns: @p@, but without @const@, @volatile@ or both qualifiers.
+ *
+ * Use: Strips qualifiers from pointer types.
+ *
+ * The @UNCONST@ macro strips @const@. It checks that @p@
+ * has type `pointer to @type@ or @const type@'; if not, a
+ * compile-time error results. Otherwise, it returns the value
+ * of @p@, converted to `pointer to (non-constant) @type@'. It
+ * will not silently strip a @volatile@ qualifier.
+ *
+ * The @UNVOLATILE@ macro is similar, except that it strips
+ * @volatile@ instead of @const@. The @UNQUALIFY@ macro strips
+ * both qualifiers.
+ */
+
+#define UNCONST(type, p) CONVERT_CAREFULLY(type *, const type *, p)
+#define UNVOLATILE(type, p) CONVERT_CAREFULLY(type *, volatile type *, p)
+#define UNQUALIFY(type, p) \
+ CONVERT_CAREFULLY(type *, const volatile type *, p)
+
+/* --- @EMPTY@ --- *
+ *
+ * Arguments: ---
+ *
+ * Returns: The empty token sequence.
+ */
+
+#define EMPTY
+
+/* --- @COMMA@ --- *
+ *
+ * Arguments: ---
+ *
+ * Returns: A `%|,|%' token, which can be usefully passed to macros to
+ * avoid argument splitting.
+ */
+
+#define COMMA ,
+
+/*----- String and character hacks ----------------------------------------*/
+
+/* --- @IS...@ --- *
+ *
+ * Arguments: @int ch@ = a character code, but not @EOF@
+ *
+ * Returns: Nonzero if @ch@ is in the relevant @<ctype.h>@ category.
+ *
+ * Use: Classifies characters, but safely even if characters are
+ * signed.
+ *
+ * There is a macro for each of the @<ctype.h>@ @is...@
+ * functions.
+ */
+
+#define CTYPE_HACK(func, ch) (func((unsigned char)(ch)))
+
+#define ISALNUM(ch) CTYPE_HACK(isalnum, ch)
+#define ISALPHA(ch) CTYPE_HACK(isalpha, ch)
+#define ISASCII(ch) CTYPE_HACK(isascii, ch)
+#define ISBLANK(ch) CTYPE_HACK(isblank, ch)
+#define ISCNTRL(ch) CTYPE_HACK(iscntrl, ch)
+#define ISDIGIT(ch) CTYPE_HACK(isdigit, ch)
+#define ISGRAPH(ch) CTYPE_HACK(isgraph, ch)
+#define ISLOWER(ch) CTYPE_HACK(islower, ch)
+#define ISPRINT(ch) CTYPE_HACK(isprint, ch)
+#define ISPUNCT(ch) CTYPE_HACK(ispunct, ch)
+#define ISSPACE(ch) CTYPE_HACK(isspace, ch)
+#define ISUPPER(ch) CTYPE_HACK(isupper, ch)
+#define ISXDIGIT(ch) CTYPE_HACK(isxdigit, ch)
+
+/* --- @TO...@ --- *
+ *
+ * Arguments: @int ch@ = a character code, but not @EOF@
+ *
+ * Returns: The converted character code.
+ *
+ * Use: Converts characters, but safely even if characters are
+ * signed.
+ *
+ * There is a macro for each of the @<ctype.h>@ @to...@
+ * functions.
+ */
+
+#define TOASCII(ch) CTYPE_HACK(toascii, ch)
+#define TOLOWER(ch) CTYPE_HACK(tolower, ch)
+#define TOUPPER(ch) CTYPE_HACK(toupper, ch)
+
+/* --- @MEMCMP@, @STRCMP@, @STRNCMP@ --- *
+ *
+ * Arguments: @const type *x, *y@ = pointers to strings
+ * @op@ = a relational operator symbol
+ * @size_t n@ = length of the strings
+ *
+ * Returns: Nonzero if the relationship between the strings satisfies the
+ * operator @op@, otherwise zero.
+ *
+ * Use: These macros mitigate the author's frequent error of failing
+ * to compare the result of the underlying standard functions
+ * against zero, effectively reversing the sense of an intended
+ * test for equality.
+ */
+
+#define MEMCMP(x, op, y, n) (memcmp((x), (y), (n)) op 0)
+#define STRCMP(x, op, y) (strcmp((x), (y)) op 0)
+#define STRNCMP(x, op, y, n) (strncmp((x), (y), (n)) op 0)
+
+/*----- Compiler-specific definitions -------------------------------------*/
+
+/* The descriptions of these are given below, with the fallback
+ * definitions.
+ */
+
+#if GCC_VERSION_P(2, 5) || CLANG_VERSION_P(3, 3)
+# define NORETURN __attribute__((__noreturn__))
+# define PRINTF_LIKE(fix, aix) __attribute__((__format__(printf, fix, aix)))
+# define SCANF_LIKE(fix, aix) __attribute__((__format__(scanf, fix, aix)))
+# define IGNORABLE __attribute__((__unused__))
+#endif
+
+#if GCC_VERSION_P(3, 4) || CLANG_VERSION_P(3, 3)
+# define MUST_CHECK __attribute__((__warn_unused_result__))
+#endif
+
+#if GCC_VERSION_P(4, 5) || CLANG_VERSION_P(3, 3)
+# define DEPRECATED(msg) __attribute__((__deprecated__(msg)))
+#elif GCC_VERSION_P(3, 1)
+# define DEPRECATED(msg) __attribute__((__deprecated__))
+#endif
+
+#if GCC_VERSION_P(4, 0) || CLANG_VERSION_P(3, 3)
+# define EXECL_LIKE(ntrail) __attribute__((__sentinel__(ntrail)))
+#endif
+
+#if GCC_VERSION_P(2, 7) || CLANG_VERSION_P(0, 0)
+# define LAUNDER(x) \
+ ({ __typeof__(x) _y; __asm__("" : "=g"(_y) : "0"(x)); _y; })
+# define ADMIRE(x) \
+ ({ __asm__("" :: "g"(x)); })
+# define ADMIRE_BUF(p, sz) \
+ ({ __asm__("" :: "m"(*(unsigned char *)p), "g"(sz) : "memory"); })
+# define RELAX do __asm__(""); while (0)
+#endif
+
+#if CLANG_VERSION_P(3, 3)
+
+# define MLIB__PRAGMA_HACK(x) _Pragma(#x)
+# define MLIB__MUFFLE_WARNINGS(warns, body) \
+ _Pragma("clang diagnostic push") \
+ warns \
+ body \
+ _Pragma("clang diagnostic pop")
+# define CLANG_WARNING(warn) \
+ MLIB__PRAGMA_HACK(clang diagnostic ignored warn)
+# define MUFFLE_WARNINGS_DECL(warns, body) \
+ MLIB__MUFFLE_WARNINGS(warns, body)
+# define MUFFLE_WARNINGS_EXPR(warns, body) \
+ __extension__ ({ MLIB__MUFFLE_WARNINGS(warns, (body);) })
+# define MUFFLE_WARNINGS_STMT(warns, body) \
+ do { MLIB__MUFFLE_WARNINGS(warns, body) } while (0)
+
+#endif
+
+#if GCC_VERSION_P(4, 6)
+
+ /* --- Diagnostic suppression in GCC: a tale of woe --- *
+ *
+ * This is extremely unpleasant, largely as a result of bugs in the GCC
+ * preprocessor's handling of @_Pragma@. The fundamental problem is
+ * that it's the preprocessor, and not the compiler proper, which
+ * detects @_Pragma@, emitting @#pragma@ lines into its output; and it
+ * does it during macro expansion, even if the macro is being expanded
+ * during argument collection. Since arguments are expanded before
+ * replacing the macro's invocation with its body, a pragma in an
+ * argument will be emitted %%\emph{before}%% any pragmata in the body,
+ * even if they appear before the argument in the body -- and even if
+ * the argument doesn't actually appear anywhere at all in the body.
+ *
+ * Another, rather less significant, problem is that @_Pragma@'s
+ * argument is a single string literal, recognized in translation phase
+ * 4, before string-literal concatenation in phase 6, so we must build
+ * pragma bodies as token lists and then stringify them.
+ *
+ * As a result, we need some subterfuge here. The @MLIB__PRAGMA_HACK@
+ * macro issues a @_Pragma@ on its argument token list, which it
+ * stringifies; this deals with the second problem. The first is
+ * trickier: we must delay expansion of @MLIB__PRAGMA_HACK@ from the
+ * argument collection phase to the body rescanning phase, and we do
+ * this by splitting the invocations between @GCC_WARNING@ macro calls:
+ * the name is left hanging from the previous call (or from
+ * @MLIB__MUFFLE_WARNINGS@, in the first case) and the body is supplied
+ * by @GCC_WARNING@, which also supplies the next @MLIB__PRAGMA_HACK@.
+ * The remaining problem is to make sure we can dispose of the final
+ * trailing @MLIB__PRAGMA_HACK@ harmlessly, which we do by introducing
+ * an extra argument @emitp@, which may be either @t@ or @nil@; this
+ * dispatches to an appropriate helper macro by means of token-pasting.
+ *
+ * I'm so sorry.
+ */
+
+# define MLIB__PRAGMA_HACK_t(x) _Pragma(#x)
+# define MLIB__PRAGMA_HACK_nil(x)
+# define MLIB__PRAGMA_HACK(emitp, x) MLIB__PRAGMA_HACK_##emitp(x)
+# define MLIB__MUFFLE_WARNINGS(warns, body) \
~mdw / mLib / blobdiff