+/* --- @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__))
~mdw / mLib / blobdiff