/* vim: set expandtab ts=4 sw=4: */
/*
* You may redistribute this program and/or modify it under the terms of
* the GNU General Public License as published by the Free Software Foundation,
* either version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
#ifndef LabelSplicer_H
#define LabelSplicer_H
#include "util/Bits.h"
#include
#include
/**
* Convert a full path (represention we can use) to a representaiton which a node
* along that path can use.
*
* @param fullPath the full route to the destination
* @param midPath a path to a node which falls somewhere within fullPath
* @return a version of fullPath which is sutible for use by node at midPath
*/
static inline uint64_t LabelSplicer_unsplice(uint64_t fullPath, uint64_t midPath)
{
return fullPath >> Bits_log2x64(midPath);
}
/**
* Splice a label and a label fragment together.
*
*/
static inline uint64_t LabelSplicer_splice(uint64_t goHere, uint64_t viaHere)
{
uint64_t log2ViaHere = Bits_log2x64(viaHere);
if (Bits_log2x64(goHere) + log2ViaHere > 59) {
// Too big, can't splice.
return UINT64_MAX;
}
return ((goHere ^ 1) << log2ViaHere) ^ viaHere;
}
/**
* Determine if the route to one node passes through another node.
* Given:
* 1. alice->bob->charlie->fred->bob
* 2. alice->bob
* 1 routes through 2.
*
* @param destination the node to route to.
* @param midPath the node which might be in the middle of the route.
* @return true if midPath is in the middle of the route to destination.
*/
static inline bool LabelSplicer_routesThrough(uint64_t destination, uint64_t midPath)
{
if (midPath > destination) {
return false;
} if (midPath < 2) {
return true;
}
uint64_t mask = UINT64_MAX >> (64 - Bits_log2x64(midPath));
return (destination & mask) == (midPath & mask);
}
#endif