lib: import ccan modules for tdb2

Imported from git://git.ozlabs.org/~ccan/ccan init-1161-g661d41f

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 47 insertions, 0 deletions

diff --git a/lib/ccan/ilog/_info b/lib/ccan/ilog/_info
new file mode 100644
index 0000000000..56de50d610
--- /dev/null
+++ b/lib/ccan/ilog/_info
@@ -0,0 +1,47 @@
+/**
+ * ilog - Integer logarithm.
+ *
+ * ilog_32() and ilog_64() compute the minimum number of bits required to store
+ *  an unsigned 32-bit or 64-bit value without any leading zero bits.
+ * This can also be thought of as the location of the highest set bit, with
+ *  counting starting from one (so that 0 returns 0, 1 returns 1, and 2**31
+ *  returns 32).
+ * When the value is known to be non-zero ilog32_nz() and ilog64_nz() can
+ *  compile into as few as two instructions, one of which may get optimized out
+ *  later.
+ * STATIC_ILOG_32 and STATIC_ILOG_64 allow computation on compile-time
+ *  constants, so other compile-time constants can be derived from them.
+ *
+ * Example:
+ *  #include <stdio.h>
+ *  #include <limits.h>
+ *  #include <ccan/ilog/ilog.h>
+ *
+ *  int main(void){
+ *    int i;
+ *    printf("ilog32(0x%08X)=%i\n",0,ilog32(0));
+ *    for(i=1;i<=STATIC_ILOG_32(USHRT_MAX);i++){
+ *      uint32_t v;
+ *      v=(uint32_t)1U<<(i-1);
+ *      //Here we know v is non-zero, so we can use ilog32_nz().
+ *      printf("ilog32(0x%08X)=%i\n",v,ilog32_nz(v));
+ *    }
+ *    return 0;
+ *  }
+ *
+ * License: LGPL (v2 or later)
+ * Author: Timothy B. Terriberry <tterribe@xiph.org>
+ */
+#include <string.h>
+#include <stdio.h>
+#include "config.h"
+
+int main(int _argc,const char *_argv[]){
+  /*Expect exactly one argument.*/
+  if(_argc!=2)return 1;
+  if(strcmp(_argv[1],"depends")==0){
+    printf("ccan/compiler\n");
+    return 0;
+  }
+  return 1;
+}