From 754c677b0bbf3ea6c7d2a73c93848f1b0d68c91e Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 20 Jun 2011 16:54:15 +0930 Subject: lib: import ccan modules for tdb2 Imported from git://git.ozlabs.org/~ccan/ccan init-1161-g661d41f Signed-off-by: Rusty Russell --- lib/ccan/cast/_info | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 lib/ccan/cast/_info (limited to 'lib/ccan/cast/_info') diff --git a/lib/ccan/cast/_info b/lib/ccan/cast/_info new file mode 100644 index 00000000000..5f82a05b8fa --- /dev/null +++ b/lib/ccan/cast/_info @@ -0,0 +1,84 @@ +#include +#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 + * License: LGPL + * + * Example: + * // Given "test" contains "3 t's in 'test string' + * #include + * #include + * #include + * + * // 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; +} -- cgit