X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fcast%2F_info;fp=ccan%2Fcast%2F_info;h=2dd9b208488bf5622826e3a4310062e346b489dc;hp=0000000000000000000000000000000000000000;hb=118ace351b789dfaca8866f84a8cd4b924941268;hpb=ce6eef4132acad78ae04a9e7c388ef932fb6411d

diff --git a/ccan/cast/_info b/ccan/cast/_info
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+#include <string.h>
+#include "config.h"
+
+/**
+ * cast - routines for safer casting.
+ *
+ * Often you want to cast in a limited way, such as removing a const or
+ * switching between integer types.  However, normal casts will work on
+ * almost any type, making them dangerous when the code changes.
+ *
+ * These C++-inspired macros serve two purposes: they make it clear the
+ * exact reason for the cast, and they also (with some compilers) cause
+ * errors when misused.
+ *
+ * Based on Jan Engelhardt's libHX macros: http://libhx.sourceforge.net/
+ *
+ * Author: Jan Engelhardt
+ * Maintainer: Rusty Russell <rusty@rustcorp.com.au>
+ * License: LGPL
+ *
+ * Example:
+ *	// Given "test" contains "3 t's in 'test string'
+ *	#include <ccan/cast/cast.h>
+ *	#include <stdint.h>
+ *	#include <stdio.h>
+ *
+ *	// Find char @orig in @str, if @repl, replace them.  Return number.
+ *	static size_t find_chars(char *str, char orig, char repl)
+ *	{
+ *		size_t i, count = 0;
+ *		for (i = 0; str[i]; i++) {
+ *			if (str[i] == orig) {
+ *				count++;
+ *				if (repl)
+ *					str[i] = repl;
+ *			}
+ *		}
+ *		return count;
+ *	}
+ *
+ *	// Terrible hash function.
+ *	static uint64_t hash_string(const unsigned char *str)
+ *	{
+ *		size_t i;
+ *		uint64_t hash = 0;
+ *		for (i = 0; str[i]; i++)
+ *			hash += str[i];
+ *		return hash;
+ *	}
+ *
+ *	int main(int argc, char *argv[])
+ *	{
+ *		uint64_t hash;
+ *
+ *		// find_chars wants a non-const string, but doesn't
+ *		// need it if repl == 0.
+ *		printf("%zu %c's in 'test string'\n",
+ *		       find_chars(cast_const(char *, "test string"),
+ *				  argv[1][0], 0),
+ *		       argv[1][0]);
+ *
+ *		// hash_string wants an unsigned char.
+ *		hash = hash_string(cast_signed(unsigned char *, argv[1]));
+ *
+ *		// Need a long long to hand to printf.
+ *		printf("Hash of '%s' = %llu\n", argv[1],
+ *		       cast_static(unsigned long long, hash));
+ *		return 0;
+ *	}
+ *		
+ */
+int main(int argc, char *argv[])
+{
+	/* Expect exactly one argument */
+	if (argc != 2)
+		return 1;
+
+	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/build_assert\n");
+		return 0;
+	}
+
+	return 1;
+}