public SnakeWithCharResults( Snake snake, List<CharSnake> charSnakes )
{
Snake = snake;
CharSnakes = charSnakes;
}
//-----------------------------------------------------------------------------------------
// MiddleSnake string
public static SnakePair? MiddleSnake( string[] pa, int a0, int N, string[] pb, int b0, int M, V VForward, V VReverse )
{
//int MAX = N + M;
int MAX = ( N + M ) / 2 + 1;
int DELTA = N - M;
VReverse.InitStub( N, M, MAX );
bool DeltaIsEven = ( DELTA % 2 ) == 0;
//Debug.WriteLine( "DELTA: " + DELTA + " which is " + ( DeltaIsEven ? "even => checking reverse" : "odd => checking forward" ) );
for ( int d = 0 ; d <= MAX ; d++ )
{
// forward
// checks against reverse D-1
for ( int k = -d ; k <= d ; k += 2 )
{
bool down = ( k == -d || ( k != d && VForward[ k - 1 ] < VForward[ k + 1 ] ) );
int xStart = down ? VForward[ k + 1 ] : VForward[ k - 1 ];
int yStart = xStart - ( down ? k + 1 : k - 1 );
int xEnd = down ? xStart : xStart + 1;
int yEnd = xEnd - k;
int snake = 0;
while ( xEnd < N && yEnd < M && pa[ xEnd + a0 ] == pb[ yEnd + b0 ] ) { xEnd++; yEnd++; snake++; }
VForward[ k ] = xEnd;
// if Δ is odd and k ϵ [ Δ - ( D - 1 ), Δ + ( D - 1 ) ]
if ( DeltaIsEven || k < DELTA - ( d - 1 ) || k > DELTA + ( d - 1 ) ) continue;
// if the path overlaps the furthest reaching reverse ( D - 1 )-path in diagonal k
if ( VForward[ k ] < VReverse[ k ] ) continue;
// overlap :)
var forward = new Snake( a0, N, b0, M, true, xStart + a0, yStart + b0, down, snake );
//Debug.WriteLine( "D:" + d + " - " + forward );
return new SnakePair { D = d, Forward = forward };
}
// backward
// checks against forward D
for ( int k = -d + DELTA ; k <= d + DELTA ; k += 2 )
{
bool up = ( k == d + DELTA || ( k != -d + DELTA && VReverse[ k - 1 ] < VReverse[ k + 1 ] ) );
int xStart = up ? VReverse[ k - 1 ] : VReverse[ k + 1 ];
int yStart = xStart - ( up ? k - 1 : k + 1 );
int xEnd = up ? xStart : xStart - 1;
int yEnd = xEnd - k;
int snake = 0;
while ( xEnd > 0 && yEnd > 0 && pa[ xEnd + a0 - 1 ] == pb[ yEnd + b0 - 1 ] ) { xEnd--; yEnd--; snake++; }
VReverse[ k ] = xEnd;
// remember: our k is actually k + Δ
// if Δ is even and k + Δ ϵ [ -D, D ]
if ( !DeltaIsEven || k < -d || k > d ) continue;
// if the path overlaps the furthest reaching forward D-path in diagonal k + Δ
if ( VReverse[ k ] > VForward[ k ] ) continue;
// overlap :)
var reverse = new Snake( a0, N, b0, M, false, xStart + a0, yStart + b0, up, snake );
//Debug.WriteLine( "D:" + d + " - " + reverse );
if ( d == 1 && ( xEnd != 0 || yEnd != 0 ) )
{
var forward = new Snake( a0, N, b0, M, true, 0, VForward, k, d, pa, pb );
return new SnakePair { D = d, Reverse = reverse, Forward = forward };
}
return new SnakePair { D = d, Reverse = reverse };
}
}
return null;
}
//-----------------------------------------------------------------------------------------
// MergeSnakes
static IList<Snake> MergeSnakes( IList<Snake> snakes, int a0, int N, int b0, int M )
{
var r = new List<Snake>( snakes.Count );
var c = new Snake( a0, N, b0, M, true, 0, 0, 0, 0, 0 );
foreach ( var s in snakes )
{
if ( s.IsForward )
{
if ( ( s.ADeleted > 0 || s.BInserted > 0 ) && c.DiagonalLength > 0 )
{
r.Add( c );
c = new Snake( a0, N, b0, M, true, c.XEnd, c.YEnd, 0, 0, 0 );
}
c.ADeleted += s.ADeleted;
c.BInserted += s.BInserted;
c.DiagonalLength += s.DiagonalLength;
Debug.Assert( c.EndPoint == s.EndPoint );
}
else
{
c.DiagonalLength += s.DiagonalLength;
if ( ( s.ADeleted > 0 || s.BInserted > 0 ) && c.DiagonalLength > 0 )
{
r.Add( c );
c = new Snake( a0, N, b0, M, true, c.XEnd, c.YEnd, 0, 0, 0 );
}
c.ADeleted += s.ADeleted;
c.BInserted += s.BInserted;
Debug.Assert( c.EndPoint == s.StartPoint );
}
}
if ( c.StartPoint != c.EndPoint ) r.Add( c );
return r;
}
static void Compare( int recursion, List<Snake> snakes,
string[] pa, int a0, int N, string[] pb, int b0, int M,
V VForward, V VReverse )
{
//Debug.WriteLine( new String( '-', recursion ) + recursion + "> Compare( " + a0 + ", " + b0 + " ) + ( " + N + ", " + M + " ) = ( " + ( a0 + N ) + ", " + ( b0 + M ) + " )" );
if ( N == 0 && M > 0 )
{
var down = new Snake( a0, N, b0, M, true, a0, b0, 0, M, 0 );
//Debug.WriteLine( "down: " + down );
snakes.Add( down );
}
if ( M == 0 && N > 0 )
{
var right = new Snake( a0, N, b0, M, true, a0, b0, N, 0, 0 );
//Debug.WriteLine( "right: " + right );
snakes.Add( right );
}
if ( N <= 0 || M <= 0 ) return;
SnakePair? middle = null;
VForward[ 1 ] = 0;
//VReverse[ N - M - 1 ] = N;
middle = DiffCommon.CalcForD.MiddleSnake( pa, a0, N, pb, b0, M, VForward, VReverse );
if ( middle == null ) throw new ApplicationException( "No middle snake" );
var m = middle.Value;
int d = middle.Value.D;
//Debug.WriteLine( "d:" + d + " " + m.Forward + " " + m.Reverse );
if ( d > 1 )
{
var xy = ( m.Forward != null ? m.Forward.StartPoint : m.Reverse.EndPoint );
var uv = ( m.Reverse != null ? m.Reverse.StartPoint : m.Forward.EndPoint );
Compare( recursion + 1, snakes, pa, a0, xy.X - a0, pb, b0, xy.Y - b0, VForward, VReverse );
if ( m.Forward != null ) snakes.Add( m.Forward );
if ( m.Reverse != null ) snakes.Add( m.Reverse );
Compare( recursion + 1, snakes, pa, uv.X, a0 + N - uv.X, pb, uv.Y, b0 + M - uv.Y, VForward, VReverse );
}
else
{
if ( m.Forward != null && m.Reverse != null ) // check for overlapping diagonal
if ( m.Forward.XMid - m.Forward.YMid == m.Reverse.XMid - m.Reverse.YMid )
{
m.Forward.DiagonalLength = m.Reverse.XMid - m.Forward.XMid;
m.Reverse.DiagonalLength = 0;
}
if ( m.Forward != null )
{
// D0
if ( m.Forward.XStart > a0 )
{
if ( m.Forward.XStart - a0 != m.Forward.YStart - b0 ) throw new ApplicationException( "Missed D0 forward" );
snakes.Add( new Snake( a0, N, b0, M, true, a0, b0, 0, 0, m.Forward.XStart - a0 ) );
}
snakes.Add( m.Forward );
}
if ( m.Reverse != null )
{
snakes.Add( m.Reverse );
// D0
if ( m.Reverse.XStart < a0 + N )
{
if ( a0 + N - m.Reverse.XStart != b0 + M - m.Reverse.YStart ) throw new ApplicationException( "Missed D0 reverse" );
snakes.Add( new Snake( a0, N, b0, M, true, m.Reverse.XStart, m.Reverse.YStart, 0, 0, a0 + N - m.Reverse.XStart ) );
}
}
}
}
static SnakeWithCharResults ConvertToLines( CompareCharsData data, bool deleted, IList<Snake> chars, Snake lineSnake )
{
//Debug.WriteLine( "\nConvertToLines " + ( deleted ? "DELETED" : "INSERTED" ) );
//Debug.WriteLine( data.ToString() );
var list = new List<CharSnake>();
foreach ( var s in chars )
{
//Debug.WriteLine( "Char " + s );
int lStart, cStart, lMid, cMid, lEnd, cEnd;
data.LineFromChar( deleted ? s.XStart : s.YStart, out lStart, out cStart );
data.LineFromChar( deleted ? s.XMid : s.YMid, out lMid, out cMid );
data.LineFromChar( deleted ? s.XEnd : s.YEnd, out lEnd, out cEnd );
//Debug.WriteLine( "LINE:CHAR Start: " + lStart + ":" + cStart + " Mid: " + lMid + ":" + cMid + " End:" + lEnd + ":" + cEnd );
if ( deleted ? s.ADeleted > 0 : s.BInserted > 0 )
{
for ( int l = lStart ; l <= lMid ; l++ )
{
var cs = new CharSnake();
cs.Line = l;
cs.IsDeleted = deleted;
cs.CharStart = ( l == lStart ? cStart : 0 );
var end = ( l == lMid ? cMid : data.LineLength( l ) );
cs.Diff = end - cs.CharStart;
cs.IsEOL = data.IsEOL( l, end );
//Debug.WriteLine( "Diff " + cs + " = '" + data.Substring( cs.CharStart, cs.Diff ) + "'" );
if ( cs.Diff > 0 || data.LineLength( l ) == 0 ) list.Add( cs );
}
}
if ( s.DiagonalLength > 0 )
{
for ( int l = lMid ; l <= lEnd ; l++ )
{
var cs = new CharSnake();
cs.Line = l;
cs.IsDeleted = deleted;
cs.CharStart = ( l == lMid ? cMid : 0 );
var end = ( l == lEnd ? cEnd : data.LineLength( l ) );
cs.Same = end - cs.CharStart;
cs.IsEOL = data.IsEOL( l, end );
//Debug.WriteLine( "Same " + cs + " = '" + data.Substring( cs.CharStart, cs.Same ) + "'" );
if ( cs.Same > 0 || data.LineLength( l ) == 0 ) list.Add( cs );
}
}
}
return new SnakeWithCharResults( lineSnake, list );
}