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/*
* 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 <http://www.gnu.org/licenses/>.
*/
#include "switch/NumberCompress.h"
#include "switch/LabelSplicer.h"
#include "util/Bits.h"
#include "util/Endian.h"
#include <stdint.h>
/**
* Splice a label and a label fragment together.
*
*/
uint64_t LabelSplicer_splice(uint64_t goHere_be, uint64_t viaHere_be)
{
uint64_t goHere = Endian_bigEndianToHost64(goHere_be);
uint64_t viaHere = Endian_bigEndianToHost64(viaHere_be);
uint64_t log2ViaHere = Bits_log2x64(viaHere);
if (Bits_log2x64(goHere) + log2ViaHere > 61) {
// Too big, can't splice.
return UINT64_MAX;
}
return Endian_hostToBigEndian64(((goHere ^ 1) << log2ViaHere) ^ viaHere);
}
/**
* Get the label for a particular destination from a given source.
* This needs to be called before handing out a label because if a source interface is
* represented using more bits than the destination interface, the destination interface
* must be padded out so that the switch will find the source and destination labels compatable.
*
* @param target_be the label for the location to send to in big endian.
* @param whoIsAsking_be the label for the node which we are sending the target to in big endian.
* @return the modified target for that node in big endian.
*/
uint64_t LabelSplicer_getLabelFor(uint64_t target_be, uint64_t whoIsAsking_be)
{
uint64_t target = Endian_bigEndianToHost64(target_be);
uint64_t whoIsAsking = Endian_bigEndianToHost64(whoIsAsking_be);
uint32_t targetBits = NumberCompress_bitsUsedForLabel(target);
uint32_t whoIsAskingBits = NumberCompress_bitsUsedForLabel(whoIsAsking);
if (targetBits >= whoIsAskingBits) {
return target_be;
}
uint32_t targetIfaceNum = NumberCompress_getDecompressed(target, targetBits);
uint64_t out = ((target & (UINT64_MAX << targetBits)) << (whoIsAskingBits - targetBits))
| NumberCompress_getCompressed(targetIfaceNum, whoIsAskingBits);
return Endian_hostToBigEndian64(out);
}
/**
* Determine if the node at the end of the given label is one hop away.
*
* @param label_be the label to test.
* @return true if the node is 1 hop away, false otherwise.
*/
bool LabelSplicer_isOneHop(uint64_t label_be)
{
uint64_t label = Endian_bigEndianToHost64(label_be);
return (int)NumberCompress_bitsUsedForLabel(label) == Bits_log2x64(label);
}
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