net_chain_bridging.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright The KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * 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, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 */
 
#ifndef PCBNEW_NET_CHAIN_BRIDGING_H
#define PCBNEW_NET_CHAIN_BRIDGING_H
 
#include <algorithm>
#include <limits>
#include <tuple>
#include <vector>
 
#include <wx/string.h>
 
#include <base_units.h>
#include <board.h>
#include <footprint.h>
#include <math/vector2d.h>
#include <netinfo.h>
#include <pad.h>
#include <pcb_track.h>
 
 
constexpr double DEFAULT_PROPAGATION_DELAY_PS_PER_MM = 5.9;  // 150 ps/in fallback when no track delay sample is available
 

inline double FootprintChainBridgingLength( const FOOTPRINT* aFootprint, const wxString& aNetChain )
{
    if( !aFootprint || aNetChain.IsEmpty() )
        return 0.0;
 
    std::vector<const PAD*> chainPads;
 
    for( const PAD* pad : aFootprint->Pads() )
    {
        const NETINFO_ITEM* pn = pad->GetNet();
 
        if( !pn || pn->GetNetChain() != aNetChain )
            continue;
 
        chainPads.push_back( pad );
    }
 
    if( chainPads.size() < 2 )
        return 0.0;
 
    int firstNet = chainPads.front()->GetNetCode();
 
    auto crossesNet = [firstNet]( const PAD* p ) { return p->GetNetCode() != firstNet; };
 
    if( !std::any_of( chainPads.begin() + 1, chainPads.end(), crossesNet ) )
        return 0.0;
 
    double maxSpan = 0.0;
 
    for( size_t i = 0; i < chainPads.size(); ++i )
    {
        for( size_t j = i + 1; j < chainPads.size(); ++j )
        {
            if( chainPads[i]->GetNetCode() == chainPads[j]->GetNetCode() )
                continue;
 
            VECTOR2D delta = VECTOR2D( chainPads[i]->GetCenter() )
                           - VECTOR2D( chainPads[j]->GetCenter() );
            maxSpan = std::max( maxSpan, delta.EuclideanNorm() );
        }
    }
 
    return maxSpan;
}
 

inline double BoardChainBridgingLength( const BOARD* aBoard, const wxString& aNetChain )
{
    if( !aBoard || aNetChain.IsEmpty() )
        return 0.0;
 
    double total = 0.0;
 
    for( const FOOTPRINT* fp : aBoard->Footprints() )
        total += FootprintChainBridgingLength( fp, aNetChain );
 
    return total;
}
 

// Forward declaration; defined below.
inline double ChainBridgingDelayPerMm( const BOARD* aBoard, const wxString& aNetChain );
 
 
inline std::tuple<double, double> BoardChainBridging( const BOARD* aBoard, const wxString& aNetChain )
{
    if( !aBoard || aNetChain.IsEmpty() )
        return { 0.0, 0.0 };
 
    double lengthIU = BoardChainBridgingLength( aBoard, aNetChain );
 
    if( lengthIU <= 0.0 )
        return { 0.0, 0.0 };
 
    double delayIU = ChainBridgingDelayPerMm( aBoard, aNetChain ) * lengthIU
                     / pcbIUScale.IU_PER_MM;
 
    return { lengthIU, delayIU };
}
 

inline int SubtractBridgingClamped( int aValue, long long aDelta )
{
    long long adjusted = static_cast<long long>( aValue ) - aDelta;
 
    return static_cast<int>( std::clamp( adjusted,
                                         0LL,
                                         static_cast<long long>( std::numeric_limits<int>::max() ) ) );
}
 

struct CHAIN_BRIDGE
{
    PAD*   padA;
    PAD*   padB;
    double length;
    double delay;
};
 

inline double ChainBridgingDelayPerMm( const BOARD* aBoard, const wxString& aNetChain )
{
    double delayIUPerMm = DEFAULT_PROPAGATION_DELAY_PS_PER_MM * pcbIUScale.IU_PER_PS;
 
    if( !aBoard || aNetChain.IsEmpty() )
        return delayIUPerMm;
 
    for( const PCB_TRACK* track : aBoard->Tracks() )
    {
        const NETINFO_ITEM* ninfo = track->GetNet();
 
        if( !ninfo || ninfo->GetNetChain() != aNetChain )
            continue;
 
        double tLen = 0.0;
        double tDelay = 0.0;
 
        std::tie( std::ignore, tLen, std::ignore, tDelay, std::ignore ) =
                aBoard->GetTrackLength( *track );
 
        if( tLen > 0.0 && tDelay > 0.0 )
        {
            delayIUPerMm = tDelay / ( tLen / pcbIUScale.IU_PER_MM );
            break;
        }
    }
 
    return delayIUPerMm;
}
 

inline std::vector<CHAIN_BRIDGE>
EnumerateChainBridges( const BOARD* aBoard, const wxString& aNetChain )
{
    std::vector<CHAIN_BRIDGE> bridges;
 
    if( !aBoard || aNetChain.IsEmpty() )
        return bridges;
 
    const double delayIUPerMm = ChainBridgingDelayPerMm( aBoard, aNetChain );
 
    for( FOOTPRINT* fp : aBoard->Footprints() )
    {
        if( !fp )
            continue;
 
        std::vector<PAD*> chainPads;
 
        for( PAD* pad : fp->Pads() )
        {
            const NETINFO_ITEM* pn = pad->GetNet();
 
            if( pn && pn->GetNetChain() == aNetChain )
                chainPads.push_back( pad );
        }
 
        if( chainPads.size() < 2 )
            continue;
 
        for( size_t i = 0; i < chainPads.size(); ++i )
        {
            for( size_t j = i + 1; j < chainPads.size(); ++j )
            {
                if( chainPads[i]->GetNetCode() == chainPads[j]->GetNetCode() )
                    continue;
 
                VECTOR2D delta = VECTOR2D( chainPads[i]->GetCenter() )
                               - VECTOR2D( chainPads[j]->GetCenter() );
                double   length = delta.EuclideanNorm();
                double   delay = delayIUPerMm * length / pcbIUScale.IU_PER_MM;
 
                bridges.push_back( CHAIN_BRIDGE{ chainPads[i], chainPads[j], length, delay } );
            }
        }
    }
 
    return bridges;
}
 
 
#endif // PCBNEW_NET_CHAIN_BRIDGING_H