From 7fec622e51753198ed8970d63053a2551ae2399d Mon Sep 17 00:00:00 2001
From: elasota <ejlasota@gmail.com>
Date: Fri, 3 Jul 2020 03:02:43 -0400
Subject: [PATCH] Add forward delete to editbox

---
 PortabilityLayer/PLEditboxWidget.cpp | 37 ++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/PortabilityLayer/PLEditboxWidget.cpp b/PortabilityLayer/PLEditboxWidget.cpp
index 490c343..d304878 100644
--- a/PortabilityLayer/PLEditboxWidget.cpp
+++ b/PortabilityLayer/PLEditboxWidget.cpp
@@ -240,12 +240,11 @@ namespace PortabilityLayer
 						HandleDownArrow(keyEvent.m_repeatCount, isShiftHeld);
 						return WidgetHandleStates::kDigested;
 					}
-#if 0
 					else if (keyEvent.m_key.m_specialKey == GpKeySpecials::kDelete)
 					{
+						HandleForwardDelete(keyEvent.m_repeatCount);
 						return WidgetHandleStates::kDigested;
 					}
-#endif
 				}
 			}
 		}
@@ -396,6 +395,40 @@ namespace PortabilityLayer
 		m_caratScrollLocked = false;
 	}
 
+	void EditboxWidget::HandleForwardDelete(const uint32_t numRepeatsRequested)
+	{
+		const size_t numPostSelChars = m_length - m_selEndChar;
+		const size_t numSelChars = m_selEndChar - m_selStartChar;
+		const size_t numPreSelChars = m_selStartChar;
+
+		size_t suffixTrim = numRepeatsRequested;
+		if (numSelChars != 0)
+			suffixTrim--;
+
+		if (suffixTrim > numPostSelChars)
+			suffixTrim = numPostSelChars;
+
+		const size_t prefixKeep = numPreSelChars;
+		const size_t suffixKeep = numPostSelChars - suffixTrim;
+
+		if (suffixKeep > 0)
+		{
+			uint8_t *moveSrc = m_chars + m_length - suffixKeep;
+			uint8_t *moveDest = m_chars + m_selStartChar;
+
+			if (moveSrc != moveDest)
+				memmove(moveDest, moveSrc, suffixKeep);
+		}
+
+		m_length = prefixKeep + suffixKeep;
+		m_selStartChar = m_selEndChar = prefixKeep;
+
+		m_caratTimer = 0;
+		Redraw();
+
+		m_caratScrollLocked = false;
+	}
+
 	void EditboxWidget::HandleUpArrow(const uint32_t numRepeatsRequested, bool shiftHeld)
 	{
 		if (!m_isMultiLine)