From 19b468ea247213ddf51ab015a7969e8b9bf98aa8 Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Thu, 17 Jan 2008 15:29:27 +0000
Subject: [PATCH] * Cursor up/down stop before empty (i.e. unused) history
 lines, now. * Added support for page up/down (works like in bash).

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23588 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 src/system/kernel/debug/debug.cpp | 49 +++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/src/system/kernel/debug/debug.cpp b/src/system/kernel/debug/debug.cpp
index d29df43c98..c7d812af41 100644
--- a/src/system/kernel/debug/debug.cpp
+++ b/src/system/kernel/debug/debug.cpp
@@ -404,8 +404,12 @@ read_line(char *buffer, int32 maxLength,
 
 						// clear the history again if we're in the current line again
 						// (the buffer we get just is the current line buffer)
-						if (historyLine == sCurrentLine)
+						if (historyLine == sCurrentLine) {
 							sLineBuffer[historyLine][0] = '\0';
+						} else if (sLineBuffer[historyLine][0] == '\0') {
+							// empty history lines are unused -- so bail out
+							break;
+						}
 
 						// swap the current line with something from the history
 						if (position > 0)
@@ -417,6 +421,46 @@ read_line(char *buffer, int32 maxLength,
 						currentHistoryLine = historyLine;
 						break;
 					}
+					case '5':	// if "5~", it's PAGE UP
+					case '6':	// if "6~", it's PAGE DOWN
+					{
+						if (readChar() != '~')
+							break;
+
+						// PAGE UP: search backward, PAGE DOWN: forward
+						int32 searchDirection = (c == '5' ? -1 : 1);
+
+						bool found = false;
+						int32 historyLine = currentHistoryLine;
+						do {
+							historyLine = (historyLine + searchDirection
+								+ HISTORY_SIZE) % HISTORY_SIZE;
+							if (historyLine == sCurrentLine)
+								break;
+
+							if (strncmp(sLineBuffer[historyLine], buffer,
+									position) == 0) {
+								found = true;
+							}
+						} while (!found);
+
+						// bail out, if we've found nothing or hit an empty
+						// (i.e. unused) history line
+						if (!found || strlen(sLineBuffer[historyLine]) == 0)
+							break;
+
+						// found a suitable line -- replace the current buffer
+						// content with it
+						strcpy(buffer, sLineBuffer[historyLine]);
+						length = strlen(buffer);
+						kprintf("%s\x1b[K", buffer + position);
+							// print the line and clear the rest
+						kprintf("\x1b[%ldD", length - position);
+							// reposition cursor
+						currentHistoryLine = historyLine;
+
+						break;
+					}
 					case 'H': // home
 					{
 						if (position > 0) {
@@ -435,8 +479,7 @@ read_line(char *buffer, int32 maxLength,
 					}
 					case '3':	// if "3~", it's DEL
 					{
-						c = readChar();
-						if (c != '~')
+						if (readChar() != '~')
 							break;
 
 						if (position < length)