// Scintilla source code edit control
/** @file CellBuffer.cxx
 ** Manages a buffer of cells.
 **/
// Copyright 1998-2001 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cstdarg>

#include <stdexcept>
#include <algorithm>

#include "Platform.h"

#include "Scintilla.h"
#include "Position.h"
#include "SplitVector.h"
#include "Partitioning.h"
#include "CellBuffer.h"
#include "UniConversion.h"

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

LineVector::LineVector() : starts(256), perLine(0) {
	Init();
}

LineVector::~LineVector() {
	starts.DeleteAll();
}

void LineVector::Init() {
	starts.DeleteAll();
	if (perLine) {
		perLine->Init();
	}
}

void LineVector::SetPerLine(PerLine *pl) {
	perLine = pl;
}

void LineVector::InsertText(Sci::Line line, Sci::Position delta) {
	starts.InsertText(line, delta);
}

void LineVector::InsertLine(Sci::Line line, Sci::Position position, bool lineStart) {
	starts.InsertPartition(line, position);
	if (perLine) {
		if ((line > 0) && lineStart)
			line--;
		perLine->InsertLine(line);
	}
}

void LineVector::SetLineStart(Sci::Line line, Sci::Position position) {
	starts.SetPartitionStartPosition(line, position);
}

void LineVector::RemoveLine(Sci::Line line) {
	starts.RemovePartition(line);
	if (perLine) {
		perLine->RemoveLine(line);
	}
}

Sci::Line LineVector::LineFromPosition(Sci::Position pos) const {
	return starts.PartitionFromPosition(pos);
}

Action::Action() {
	at = startAction;
	position = 0;
	data = 0;
	lenData = 0;
	mayCoalesce = false;
}

Action::~Action() {
	Destroy();
}

void Action::Create(actionType at_, Sci::Position position_, const char *data_, Sci::Position lenData_, bool mayCoalesce_) {
	delete []data;
	data = NULL;
	position = position_;
	at = at_;
	if (lenData_) {
		data = new char[lenData_];
		memcpy(data, data_, lenData_);
	}
	lenData = lenData_;
	mayCoalesce = mayCoalesce_;
}

void Action::Destroy() {
	delete []data;
	data = 0;
}

void Action::Grab(Action *source) {
	delete []data;

	position = source->position;
	at = source->at;
	data = source->data;
	lenData = source->lenData;
	mayCoalesce = source->mayCoalesce;

	// Ownership of source data transferred to this
	source->position = 0;
	source->at = startAction;
	source->data = 0;
	source->lenData = 0;
	source->mayCoalesce = true;
}

// The undo history stores a sequence of user operations that represent the user's view of the
// commands executed on the text.
// Each user operation contains a sequence of text insertion and text deletion actions.
// All the user operations are stored in a list of individual actions with 'start' actions used
// as delimiters between user operations.
// Initially there is one start action in the history.
// As each action is performed, it is recorded in the history. The action may either become
// part of the current user operation or may start a new user operation. If it is to be part of the
// current operation, then it overwrites the current last action. If it is to be part of a new
// operation, it is appended after the current last action.
// After writing the new action, a new start action is appended at the end of the history.
// The decision of whether to start a new user operation is based upon two factors. If a
// compound operation has been explicitly started by calling BeginUndoAction and no matching
// EndUndoAction (these calls nest) has been called, then the action is coalesced into the current
// operation. If there is no outstanding BeginUndoAction call then a new operation is started
// unless it looks as if the new action is caused by the user typing or deleting a stream of text.
// Sequences that look like typing or deletion are coalesced into a single user operation.

UndoHistory::UndoHistory() {

	lenActions = 100;
	actions = new Action[lenActions];
	maxAction = 0;
	currentAction = 0;
	undoSequenceDepth = 0;
	savePoint = 0;
	tentativePoint = -1;

	actions[currentAction].Create(startAction);
}

UndoHistory::~UndoHistory() {
	delete []actions;
	actions = 0;
}

void UndoHistory::EnsureUndoRoom() {
	// Have to test that there is room for 2 more actions in the array
	// as two actions may be created by the calling function
	if (currentAction >= (lenActions - 2)) {
		// Run out of undo nodes so extend the array
		const int lenActionsNew = lenActions * 2;
		Action *actionsNew = new Action[lenActionsNew];
		for (int act = 0; act <= currentAction; act++)
			actionsNew[act].Grab(&actions[act]);
		delete []actions;
		lenActions = lenActionsNew;
		actions = actionsNew;
	}
}

const char *UndoHistory::AppendAction(actionType at, Sci::Position position, const char *data, Sci::Position lengthData,
	bool &startSequence, bool mayCoalesce) {
	EnsureUndoRoom();
	//Platform::DebugPrintf("%% %d action %d %d %d\n", at, position, lengthData, currentAction);
	//Platform::DebugPrintf("^ %d action %d %d\n", actions[currentAction - 1].at,
	//	actions[currentAction - 1].position, actions[currentAction - 1].lenData);
	if (currentAction < savePoint) {
		savePoint = -1;
	}
	int oldCurrentAction = currentAction;
	if (currentAction >= 1) {
		if (0 == undoSequenceDepth) {
			// Top level actions may not always be coalesced
			int targetAct = -1;
			const Action *actPrevious = &(actions[currentAction + targetAct]);
			// Container actions may forward the coalesce state of Scintilla Actions.
			while ((actPrevious->at == containerAction) && actPrevious->mayCoalesce) {
				targetAct--;
				actPrevious = &(actions[currentAction + targetAct]);
			}
			// See if current action can be coalesced into previous action
			// Will work if both are inserts or deletes and position is same
#if defined(_MSC_VER) && defined(_PREFAST_)
			// Visual Studio 2013 Code Analysis wrongly believes actions can be NULL at its next reference
			__analysis_assume(actions);
#endif
			if ((currentAction == savePoint) || (currentAction == tentativePoint)) {
				currentAction++;
			} else if (!actions[currentAction].mayCoalesce) {
				// Not allowed to coalesce if this set
				currentAction++;
			} else if (!mayCoalesce || !actPrevious->mayCoalesce) {
				currentAction++;
			} else if (at == containerAction || actions[currentAction].at == containerAction) {
				;	// A coalescible containerAction
			} else if ((at != actPrevious->at) && (actPrevious->at != startAction)) {
				currentAction++;
			} else if ((at == insertAction) &&
			           (position != (actPrevious->position + actPrevious->lenData))) {
				// Insertions must be immediately after to coalesce
				currentAction++;
			} else if (at == removeAction) {
				if ((lengthData == 1) || (lengthData == 2)) {
					if ((position + lengthData) == actPrevious->position) {
						; // Backspace -> OK
					} else if (position == actPrevious->position) {
						; // Delete -> OK
					} else {
						// Removals must be at same position to coalesce
						currentAction++;
					}
				} else {
					// Removals must be of one character to coalesce
					currentAction++;
				}
			} else {
				// Action coalesced.
			}

		} else {
			// Actions not at top level are always coalesced unless this is after return to top level
			if (!actions[currentAction].mayCoalesce)
				currentAction++;
		}
	} else {
		currentAction++;
	}
	startSequence = oldCurrentAction != currentAction;
	const int actionWithData = currentAction;
	actions[currentAction].Create(at, position, data, lengthData, mayCoalesce);
	currentAction++;
	actions[currentAction].Create(startAction);
	maxAction = currentAction;
	return actions[actionWithData].data;
}

void UndoHistory::BeginUndoAction() {
	EnsureUndoRoom();
	if (undoSequenceDepth == 0) {
		if (actions[currentAction].at != startAction) {
			currentAction++;
			actions[currentAction].Create(startAction);
			maxAction = currentAction;
		}
		actions[currentAction].mayCoalesce = false;
	}
	undoSequenceDepth++;
}

void UndoHistory::EndUndoAction() {
	PLATFORM_ASSERT(undoSequenceDepth > 0);
	EnsureUndoRoom();
	undoSequenceDepth--;
	if (0 == undoSequenceDepth) {
		if (actions[currentAction].at != startAction) {
			currentActiHTTP/1.1 200 OK
Connection: keep-alive
Connection: keep-alive
Content-Disposition: inline; filename="CellBuffer.cxx"
Content-Disposition: inline; filename="CellBuffer.cxx"
Content-Length: 23797
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Content-Security-Policy: default-src 'none'
Content-Security-Policy: default-src 'none'
Content-Type: text/plain; charset=UTF-8
Content-Type: text/plain; charset=UTF-8
Date: Sat, 18 Oct 2025 08:49:59 UTC
ETag: "290478c1072c3470de78eee707a98cc96044b6d7"
ETag: "290478c1072c3470de78eee707a98cc96044b6d7"
Expires: Tue, 16 Oct 2035 08:49:59 GMT
Expires: Tue, 16 Oct 2035 08:49:59 GMT
Last-Modified: Sat, 18 Oct 2025 08:49:59 GMT
Last-Modified: Sat, 18 Oct 2025 08:49:59 GMT
Server: OpenBSD httpd
Server: OpenBSD httpd
X-Content-Type-Options: nosniff
X-Content-Type-Options: nosniff

// Scintilla source code edit control
/** @file CellBuffer.cxx
 ** Manages a buffer of cells.
 **/
// Copyright 1998-2001 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cstdarg>

#include <stdexcept>
#include <algorithm>

#include "Platform.h"

#include "Scintilla.h"
#include "Position.h"
#include "SplitVector.h"
#include "Partitioning.h"
#include "CellBuffer.h"
#include "UniConversion.h"

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

LineVector::LineVector() : starts(256), perLine(0) {
	Init();
}

LineVector::~LineVector() {
	starts.DeleteAll();
}

void LineVector::Init() {
	starts.DeleteAll();
	if (perLine) {
		perLine->Init();
	}
}

void LineVector::SetPerLine(PerLine *pl) {
	perLine = pl;
}

void LineVector::InsertText(Sci::Line line, Sci::Position delta) {
	starts.InsertText(line, delta);
}

void LineVector::InsertLine(Sci::Line line, Sci::Position position, bool lineStart) {
	starts.InsertPartition(line, position);
	if (perLine) {
		if ((line > 0) && lineStart)
			line--;
		perLine->InsertLine(line);
	}
}

void LineVector::SetLineStart(Sci::Line line, Sci::Position position) {
	starts.SetPartitionStartPosition(line, position);
}

void LineVector::RemoveLine(Sci::Line line) {
	starts.RemovePartition(line);
	if (perLine) {
		perLine->RemoveLine(line);
	}
}

Sci::Line LineVector::LineFromPosition(Sci::Position pos) const {
	return starts.PartitionFromPosition(pos);
}

Action::Action() {
	at = startAction;
	position = 0;
	data = 0;
	lenData = 0;
	mayCoalesce = false;
}

Action::~Action() {
	Destroy();
}

void Action::Create(actionType at_, Sci::Position position_, const char *data_, Sci::Position lenData_, bool mayCoalesce_) {
	delete []data;
	data = NULL;
	position = position_;
	at = at_;
	if (lenData_) {
		data = new char[lenData_];
		memcpy(data, data_, lenData_);
	}
	lenData = lenData_;
	mayCoalesce = mayCoalesce_;
}

void Action::Destroy() {
	delete []data;
	data = 0;
}

void Action::Grab(Action *source) {
	delete []data;

	position = source->position;
	at = source->at;
	data = source->data;
	lenData = source->lenData;
	mayCoalesce = source->mayCoalesce;

	// Ownership of source data transferred to this
	source->position = 0;
	source->at = startAction;
	source->data = 0;
	source->lenData = 0;
	source->mayCoalesce = true;
}

// The undo history stores a sequence of user operations that represent the user's view of the
// commands executed on the text.
// Each user operation contains a sequence of text insertion and text deletion actions.
// All the user operations are stored in a list of individual actions with 'start' actions used
// as delimiters between user operations.
// Initially there is one start action in the history.
// As each action is performed, it is recorded in the history. The action may either become
// part of the current user operation or may start a new user operation. If it is to be part of the
// current operation, then it overwrites the current last action. If it is to be part of a new
// operation, it is appended after the current last action.
// After writing the new action, a new start action is appended at the end of the history.
// The decision of whether to start a new user operation is based upon two factors. If a
// compound operation has been explicitly started by calling BeginUndoAction and no matching
// EndUndoAction (these calls nest) has been called, then the action is coalesced into the current
// operation. If there is no outstanding BeginUndoAction call then a new operation is started
// unless it looks as if the new action is caused by the user typing or deleting a stream of text.
// Sequences that look like typing or deletion are coalesced into a single user operation.

UndoHistory::UndoHistory() {

	lenActions = 100;
	actions = new Action[lenActions];
	maxAction = 0;
	currentAction = 0;
	undoSequenceDepth = 0;
	savePoint = 0;
	tentativePoint = -1;

	actions[currentAction].Create(startAction);
}

UndoHistory::~UndoHistory() {
	delete []actions;
	actions = 0;
}

void UndoHistory::EnsureUndoRoom() {
	// Have to test that there is room for 2 more actions in the array
	// as two actions may be created by the calling function
	if (currentAction >= (lenActions - 2)) {
		// Run out of undo nodes so extend the array
		const int lenActionsNew = lenActions * 2;
		Action *actionsNew = new Action[lenActionsNew];
		for (int act = 0; act <= currentAction; act++)
			actionsNew[act].Grab(&actions[act]);
		delete []actions;
		lenActions = lenActionsNew;
		actions = actionsNew;
	}
}

const char *UndoHistory::AppendAction(actionType at, Sci::Position position, const char *data, Sci::Position lengthData,
	bool &startSequence, bool mayCoalesce) {
	EnsureUndoRoom();
	//Platform::DebugPrintf("%% %d action %d %d %d\n", at, position, lengthData, currentAction);
	//Platform::DebugPrintf("^ %d action %d %d\n", actions[currentAction - 1].at,
	//	actions[currentAction - 1].position, actions[currentAction - 1].lenData);
	if (currentAction < savePoint) {
		savePoint = -1;
	}
	int oldCurrentAction = currentAction;
	if (currentAction >= 1) {
		if (0 == undoSequenceDepth) {
			// Top level actions may not always be coalesced
			int targetAct = -1;
			const Action *actPrevious = &(actions[currentAction + targetAct]);
			// Container actions may forward the coalesce state of Scintilla Actions.
			while ((actPrevious->at == containerAction) && actPrevious->mayCoalesce) {
				targetAct--;
				actPrevious = &(actions[currentAction + targetAct]);
			}
			// See if current action can be coalesced into previous action
			// Will work if both are inserts or deletes and position is same
#if defined(_MSC_VER) && defined(_PREFAST_)
			// Visual Studio 2013 Code Analysis wrongly believes actions can be NULL at its next reference
			__analysis_assume(actions);
#endif
			if ((currentAction == savePoint) || (currentAction == tentativePoint)) {
				currentAction++;
			} else if (!actions[currentAction].mayCoalesce) {
				// Not allowed to coalesce if this set
				currentAction++;
			} else if (!mayCoalesce || !actPrevious->mayCoalesce) {
				currentAction++;
			} else if (at == containerAction || actions[currentAction].at == containerAction) {
				;	// A coalescible containerAction
			} else if ((at != actPrevious->at) && (actPrevious->at != startAction)) {
				currentAction++;
			} else if ((at == insertAction) &&
			           (position != (actPrevious->position + actPrevious->lenData))) {
				// Insertions must be immediately after to coalesce
				currentAction++;
			} else if (at == removeAction) {
				if ((lengthData == 1) || (lengthData == 2)) {
					if ((position + lengthData) == actPrevious->position) {
						; // Backspace -> OK
					} else if (position == actPrevious->position) {
						; // Delete -> OK
					} else {
						// Removals must be at same position to coalesce
						currentAction++;
					}
				} else {
					// Removals must be of one character to coalesce
					currentAction++;
				}
			} else {
				// Action coalesced.
			}

		} else {
			// Actions not at top level are always coalesced unless this is after return to top level
			if (!actions[currentAction].mayCoalesce)
				currentAction++;
		}
	} else {
		currentAction++;
	}
	startSequence = oldCurrentAction != currentAction;
	const int actionWithData = currentAction;
	actions[currentAction].Create(at, position, data, lengthData, mayCoalesce);
	currentAction++;
	actions[currentAction].Create(startAction);
	maxAction = currentAction;
	return actions[actionWithData].data;
}

void UndoHistory::BeginUndoAction() {
	EnsureUndoRoom();
	if (undoSequenceDepth == 0) {
		if (actions[currentAction].at != startAction) {
			currentAction++;
			actions[currentAction].Create(startAction);
			maxAction = currentAction;
		}
		actions[currentAction].mayCoalesce = false;
	}
	undoSequenceDepth++;
}

void UndoHistory::EndUndoAction() {
	PLATFORM_ASSERT(undoSequenceDepth > 0);
	EnsureUndoRoom();
	undoSequenceDepth--;
	if (0 == undoSequenceDepth) {
		if (actions[currentAction].at != startAction) {
			currentAction++;
			actions[currentAction].Create(startAction);
			maxAction = currentAction;
		}
		actions[currentAction].mayCoalesce = false;
	}
}

void UndoHistory::DropUndoSequence() {
	undoSequenceDepth = 0;
}

void UndoHistory::DeleteUndoHistory() {
	for (int i = 1; i < maxAction; i++)
		actions[i].Destroy();
	maxAction = 0;
	currentAction = 0;
	actions[currentAction].Create(startAction);
	savePoint = 0;
	tentativePoint = -1;
}

void UndoHistory::SetSavePoint() {
	savePoint = currentAction;
}

bool UndoHistory::IsSavePoint() const {
	return savePoint == currentAction;
}

void UndoHistory::TentativeStart() {
	tentativePoint = currentAction;
}

void UndoHistory::TentativeCommit() {
	tentativePoint = -1;
	// Truncate undo history
	maxAction = currentAction;
}

int UndoHistory::TentativeSteps() {
	// Drop any trailing startAction
	if (actions[currentAction].at == startAction && currentAction > 0)
		currentAction--;
	if (tentativePoint >= 0)
		return currentAction - tentativePoint;
	else
		return -1;
}

bool UndoHistory::CanUndo() const {
	return (currentAction > 0) && (maxAction > 0);
}

int UndoHistory::StartUndo() {
	// Drop any trailing startAction
	if (actions[currentAction].at == startAction && currentAction > 0)
		currentAction--;

	// Count the steps in this action
	int act = currentAction;
	while (actions[act].at != startAction && act > 0) {
		act--;
	}
	return currentAction - act;
}

const Action &UndoHistory::GetUndoStep() const {
	return actions[currentAction];
}

void UndoHistory::CompletedUndoStep() {
	currentAction--;
}

bool UndoHistory::CanRedo() const {
	return maxAction > currentAction;
}

int UndoHistory::StartRedo() {
	// Drop any leading startAction
	if (currentAction < maxAction && actions[currentAction].at == startAction)
		currentAction++;

	// Count the steps in this action
	int act = currentAction;
	while (act < maxAction && actions[act].at != startAction) {
		act++;
	}
	return act - currentAction;
}

const Action &UndoHistory::GetRedoStep() const {
	return actions[currentAction];
}

void UndoHistory::CompletedRedoStep() {
	currentAction++;
}

CellBuffer::CellBuffer() {
	readOnly = false;
	utf8LineEnds = 0;
	collectingUndo = true;
}

CellBuffer::~CellBuffer() {
}

char CellBuffer::CharAt(Sci::Position position) const {
	return substance.ValueAt(position);
}

void CellBuffer::GetCharRange(char *buffer, Sci::Position position, Sci::Position lengthRetrieve) const {
	if (lengthRetrieve <= 0)
		return;
	if (position < 0)
		return;
	if ((position + lengthRetrieve) > substance.Length()) {
		Platform::DebugPrintf("Bad GetCharRange %d for %d of %d\n", position,
		                      lengthRetrieve, substance.Length());
		return;
	}
	substance.GetRange(buffer, position, lengthRetrieve);
}

char CellBuffer::StyleAt(Sci::Position position) const {
	return style.ValueAt(position);
}

void CellBuffer::GetStyleRange(unsigned char *buffer, Sci::Position position, Sci::Position lengthRetrieve) const {
	if (lengthRetrieve < 0)
		return;
	if (position < 0)
		return;
	if ((position + lengthRetrieve) > style.Length()) {
		Platform::DebugPrintf("Bad GetStyleRange %d for %d of %d\n", position,
		                      lengthRetrieve, style.Length());
		return;
	}
	style.GetRange(reinterpret_cast<char *>(buffer), position, lengthRetrieve);
}

const char *CellBuffer::BufferPointer() {
	return substance.BufferPointer();
}

const char *CellBuffer::RangePointer(Sci::Position position, Sci::Position rangeLength) {
	return substance.RangePointer(position, rangeLength);
}

Sci::Position CellBuffer::GapPosition() const {
	return substance.GapPosition();
}

// The char* returned is to an allocation owned by the undo history
const char *CellBuffer::InsertString(Sci::Position position, const char *s, Sci::Position insertLength, bool &startSequence) {
	// InsertString and DeleteChars are the bottleneck though which all changes occur
	const char *data = s;
	if (!readOnly) {
		if (collectingUndo) {
			// Save into the undo/redo stack, but only the characters - not the formatting
			// This takes up about half load time
			data = uh.AppendAction(insertAction, position, s, insertLength, startSequence);
		}

		BasicInsertString(position, s, insertLength);
	}
	return data;
}

bool CellBuffer::SetStyleAt(Sci::Position position, char styleValue) {
	const char curVal = style.ValueAt(position);
	if (curVal != styleValue) {
		style.SetValueAt(position, styleValue);
		return true;
	} else {
		return false;
	}
}

bool CellBuffer::SetStyleFor(Sci::Position position, Sci::Position lengthStyle, char styleValue) {
	bool changed = false;
	PLATFORM_ASSERT(lengthStyle == 0 ||
		(lengthStyle > 0 && lengthStyle + position <= style.Length()));
	while (lengthStyle--) {
		const char curVal = style.ValueAt(position);
		if (curVal != styleValue) {
			style.SetValueAt(position, styleValue);
			changed = true;
		}
		position++;
	}
	return changed;
}

// The char* returned is to an allocation owned by the undo history
const char *CellBuffer::DeleteChars(Sci::Position position, Sci::Position deleteLength, bool &startSequence) {
	// InsertString and DeleteChars are the bottleneck though which all changes occur
	PLATFORM_ASSERT(deleteLength > 0);
	const char *data = 0;
	if (!readOnly) {
		if (collectingUndo) {
			// Save into the undo/redo stack, but only the characters - not the formatting
			// The gap would be moved to position anyway for the deletion so this doesn't cost extra
			data = substance.RangePointer(position, deleteLength);
			data = uh.AppendAction(removeAction, position, data, deleteLength, startSequence);
		}

		BasicDeleteChars(position, deleteLength);
	}
	return data;
}

Sci::Position CellBuffer::Length() const {
	return substance.Length();
}

void CellBuffer::Allocate(Sci::Position newSize) {
	substance.ReAllocate(newSize);
	style.ReAllocate(newSize);
}

void CellBuffer::SetLineEndTypes(int utf8LineEnds_) {
	if (utf8LineEnds != utf8LineEnds_) {
		utf8LineEnds = utf8LineEnds_;
		ResetLineEnds();
	}
}

bool CellBuffer::ContainsLineEnd(const char *s, Sci::Position length) const {
	unsigned char chBeforePrev = 0;
	unsigned char chPrev = 0;
	for (Sci::Position i = 0; i < length; i++) {
		const unsigned char ch = s[i];
		if ((ch == '\r') || (ch == '\n')) {
			return true;
		} else if (utf8LineEnds) {
			const unsigned char back3[3] = { chBeforePrev, chPrev, ch };
			if (UTF8IsSeparator(back3) || UTF8IsNEL(back3 + 1)) {
				return true;
			}
		}
		chBeforePrev = chPrev;
		chPrev = ch;
	}
	return false;
}

void CellBuffer::SetPerLine(PerLine *pl) {
	lv.SetPerLine(pl);
}

Sci::Line CellBuffer::Lines() const {