Add a mode to skip over null characters that were inserted due to 2-column characters for the copy operation

Author: migueldeicaza

Sources/SwiftTerm/Buffer.swift

@@ -496,10 +496,10 @@ public final class Buffer {
         }
     }
 
-    func translateBufferLineToString (lineIndex: Int, trimRight: Bool, startCol: Int = 0, endCol: Int = -1) -> String
+    func translateBufferLineToString (lineIndex: Int, trimRight: Bool, startCol: Int = 0, endCol: Int = -1, skipNullCellsFollowingWide: Bool = false) -> String
     {
         let line = _lines [lineIndex]
-        return line.translateToString(trimRight: trimRight, startCol: startCol, endCol: endCol)
+        return line.translateToString(trimRight: trimRight, startCol: startCol, endCol: endCol, skipNullCellsFollowingWide: skipNullCellsFollowingWide)
     }
 
     func setupTabStops (index: Int = -1, tabStopWidth: Int)

Sources/SwiftTerm/BufferLine.swift

@@ -247,15 +247,37 @@ public final class BufferLine: CustomDebugStringConvertible {
     /// - Parameter startCol: the starting column to copy the data from, defaults toe zero if not provided
     /// - Parameter endCol: the end column (not included) to consume.  If the value -1, this copies all the way to the end
     /// - Returns: a string containing the contents of the BufferLine from [startCol..<endCol]
-    public func translateToString (trimRight: Bool = false, startCol: Int = 0, endCol: Int = -1) -> String
+    public func translateToString (trimRight: Bool = false, startCol: Int = 0, endCol: Int = -1, skipNullCellsFollowingWide: Bool = false) -> String
     {
         var ec = endCol == -1 ? dataSize : endCol
         if trimRight {
             ec = max (startCol, min (ec, getTrimmedLength()))
         }
+        let limit = max(ec, startCol)
+        if !skipNullCellsFollowingWide {
+            var result = ""
+            for i in startCol..<limit {
+                result.append (data [i].getCharacter ())
+            }
+            return result
+        }
         var result = ""
-        for i in startCol..<max(ec,startCol) {
-            result.append (data [i].getCharacter ())
+        var idx = startCol
+        while idx < limit {
+            if idx > 0 && data [idx].code == 0 && data [idx-1].width == 2 {
+                idx += 1
+                continue
+            }
+            let cell = data [idx]
+            result.append (cell.getCharacter ())
+            if cell.width == 2 {
+                let nextIndex = idx + 1
+                if nextIndex < limit && data [nextIndex].code == 0 {
+                    idx += 2
+                    continue
+                }
+            }
+            idx += 1
         }
         return result
     }
@@ -275,4 +297,3 @@ public final class BufferLine: CustomDebugStringConvertible {
         }
     }
 }
-

Sources/SwiftTerm/Terminal.swift

@@ -5367,7 +5367,7 @@ open class Terminal {
 
     func translateBufferLineToString (buffer: Buffer, line: Int, start: Int, end: Int) -> String
     {
-        buffer.translateBufferLineToString(lineIndex: line, trimRight: true, startCol: start, endCol: end).replacingOccurrences(of: "\u{0}", with: " ")
+        buffer.translateBufferLineToString(lineIndex: line, trimRight: true, startCol: start, endCol: end, skipNullCellsFollowingWide: true).replacingOccurrences(of: "\u{0}", with: " ")
     }
 }