Add an UI to enable/disable specific overlay handlers.

[TortoiseGit.git] / ext / scintilla / src / CellBuffer.cxx

// 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 <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>

#include "Platform.h"

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

#ifdef SCI_NAMESPACE
using namespace Scintilla;
#endif

MarkerHandleSet::MarkerHandleSet() {
        root = 0;
}

MarkerHandleSet::~MarkerHandleSet() {
        MarkerHandleNumber *mhn = root;
        while (mhn) {
                MarkerHandleNumber *mhnToFree = mhn;
                mhn = mhn->next;
                delete mhnToFree;
        }
        root = 0;
}

int MarkerHandleSet::Length() const {
        int c = 0;
        MarkerHandleNumber *mhn = root;
        while (mhn) {
                c++;
                mhn = mhn->next;
        }
        return c;
}

int MarkerHandleSet::NumberFromHandle(int handle) const {
        MarkerHandleNumber *mhn = root;
        while (mhn) {
                if (mhn->handle == handle) {
                        return mhn->number;
                }
                mhn = mhn->next;
        }
        return - 1;
}

int MarkerHandleSet::MarkValue() const {
        unsigned int m = 0;
        MarkerHandleNumber *mhn = root;
        while (mhn) {
                m |= (1 << mhn->number);
                mhn = mhn->next;
        }
        return m;
}

bool MarkerHandleSet::Contains(int handle) const {
        MarkerHandleNumber *mhn = root;
        while (mhn) {
                if (mhn->handle == handle) {
                        return true;
                }
                mhn = mhn->next;
        }
        return false;
}

bool MarkerHandleSet::InsertHandle(int handle, int markerNum) {
        MarkerHandleNumber *mhn = new MarkerHandleNumber;
        if (!mhn)
                return false;
        mhn->handle = handle;
        mhn->number = markerNum;
        mhn->next = root;
        root = mhn;
        return true;
}

void MarkerHandleSet::RemoveHandle(int handle) {
        MarkerHandleNumber **pmhn = &root;
        while (*pmhn) {
                MarkerHandleNumber *mhn = *pmhn;
                if (mhn->handle == handle) {
                        *pmhn = mhn->next;
                        delete mhn;
                        return;
                }
                pmhn = &((*pmhn)->next);
        }
}

bool MarkerHandleSet::RemoveNumber(int markerNum) {
        bool performedDeletion = false;
        MarkerHandleNumber **pmhn = &root;
        while (*pmhn) {
                MarkerHandleNumber *mhn = *pmhn;
                if (mhn->number == markerNum) {
                        *pmhn = mhn->next;
                        delete mhn;
                        performedDeletion = true;
                } else {
                        pmhn = &((*pmhn)->next);
                }
        }
        return performedDeletion;
}

void MarkerHandleSet::CombineWith(MarkerHandleSet *other) {
        MarkerHandleNumber **pmhn = &root;
        while (*pmhn) {
                pmhn = &((*pmhn)->next);
        }
        *pmhn = other->root;
        other->root = 0;
}

LineVector::LineVector() : starts(256) {
        handleCurrent = 1;

        Init();
}

LineVector::~LineVector() {
        starts.DeleteAll();
        for (int line = 0; line < markers.Length(); line++) {
                delete markers[line];
                markers[line] = 0;
        }
        markers.DeleteAll();
        levels.DeleteAll();
}

void LineVector::Init() {
        starts.DeleteAll();
        for (int line = 0; line < markers.Length(); line++) {
                delete markers[line];
                markers[line] = 0;
        }
        markers.DeleteAll();
        levels.DeleteAll();
}

void LineVector::ExpandLevels(int sizeNew) {
        levels.InsertValue(levels.Length(), sizeNew - levels.Length(), SC_FOLDLEVELBASE);
}

void LineVector::ClearLevels() {
        levels.DeleteAll();
}

int LineVector::SetLevel(int line, int level) {
        int prev = 0;
        if ((line >= 0) && (line < Lines())) {
                if (!levels.Length()) {
                        ExpandLevels(Lines() + 1);
                }
                prev = levels[line];
                if (prev != level) {
                        levels[line] = level;
                }
        }
        return prev;
}

int LineVector::GetLevel(int line) {
        if (levels.Length() && (line >= 0) && (line < Lines())) {
                return levels[line];
        } else {
                return SC_FOLDLEVELBASE;
        }
}

void LineVector::InsertText(int line, int delta) {
        starts.InsertText(line, delta);
}

void LineVector::InsertLine(int line, int position) {
        starts.InsertPartition(line, position);
        if (markers.Length()) {
                markers.Insert(line, 0);
        }
        if (levels.Length()) {
                int level = SC_FOLDLEVELBASE;
                if ((line > 0) && (line < Lines())) {
                        level = levels[line-1] & ~SC_FOLDLEVELWHITEFLAG;
                }
                levels.InsertValue(line, 1, level);
        }
}

void LineVector::SetLineStart(int line, int position) {
        starts.SetPartitionStartPosition(line, position);
}

void LineVector::RemoveLine(int line) {
        starts.RemovePartition(line);
        // Retain the markers from the deleted line by oring them into the previous line
        if (markers.Length()) {
                if (line > 0) {
                        MergeMarkers(line - 1);
                }
                markers.Delete(line);
        }
        if (levels.Length()) {
                // Move up following lines but merge header flag from this line
                // to line before to avoid a temporary disappearence causing expansion.
                int firstHeader = levels[line] & SC_FOLDLEVELHEADERFLAG;
                levels.Delete(line);
                if (line > 0)
                        levels[line-1] |= firstHeader;
        }
}

int LineVector::LineFromPosition(int pos) {
        return starts.PartitionFromPosition(pos);
}

int LineVector::MarkValue(int line) {
        if (markers.Length() && markers[line])
                return markers[line]->MarkValue();
        else
                return 0;
}

int LineVector::AddMark(int line, int markerNum) {
        handleCurrent++;
        if (!markers.Length()) {
                // No existing markers so allocate one element per line
                markers.InsertValue(0, Lines(), 0);
        }
        if (!markers[line]) {
                // Need new structure to hold marker handle
                markers[line] = new MarkerHandleSet();
                if (!markers[line])
                        return - 1;
        }
        markers[line]->InsertHandle(handleCurrent, markerNum);

        return handleCurrent;
}

void LineVector::MergeMarkers(int pos) {
        if (markers[pos + 1] != NULL) {
                if (markers[pos] == NULL)
                        markers[pos] = new MarkerHandleSet;
                markers[pos]->CombineWith(markers[pos + 1]);
                delete markers[pos + 1];
                markers[pos + 1] = NULL;
        }
}

void LineVector::DeleteMark(int line, int markerNum, bool all) {
        if (markers.Length() && markers[line]) {
                if (markerNum == -1) {
                        delete markers[line];
                        markers[line] = NULL;
                } else {
                        bool performedDeletion = markers[line]->RemoveNumber(markerNum);
                        while (all && performedDeletion) {
                                performedDeletion = markers[line]->RemoveNumber(markerNum);
                        }
                        if (markers[line]->Length() == 0) {
                                delete markers[line];
                                markers[line] = NULL;
                        }
                }
        }
}

void LineVector::DeleteMarkFromHandle(int markerHandle) {
        int line = LineFromHandle(markerHandle);
        if (line >= 0) {
                markers[line]->RemoveHandle(markerHandle);
                if (markers[line]->Length() == 0) {
                        delete markers[line];
                        markers[line] = NULL;
                }
        }
}

int LineVector::LineFromHandle(int markerHandle) {
        if (markers.Length()) {
                for (int line = 0; line < Lines(); line++) {
                        if (markers[line]) {
                                if (markers[line]->Contains(markerHandle)) {
                                        return line;
                                }
                        }
                }
        }
        return -1;
}

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

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

void Action::Create(actionType at_, int position_, char *data_, int lenData_, bool mayCoalesce_) {
        delete []data;
        position = position_;
        at = at_;
        data = data_;
        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;

        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
                int lenActionsNew = lenActions * 2;
                Action *actionsNew = new Action[lenActionsNew];
                if (!actionsNew)
                        return;
                for (int act = 0; act <= currentAction; act++)
                        actionsNew[act].Grab(&actions[act]);
                delete []actions;
                lenActions = lenActionsNew;
                actions = actionsNew;
        }
}

void UndoHistory::AppendAction(actionType at, int position, char *data, int lengthData,
        bool &startSequence) {
        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
                        Action &actPrevious = actions[currentAction - 1];
                        // See if current action can be coalesced into previous action
                        // Will work if both are inserts or deletes and position is same
                        if (at != actPrevious.at) {
                                currentAction++;
                        } else if (currentAction == savePoint) {
                                currentAction++;
                        } else if ((at == insertAction) &&
                                   (position != (actPrevious.position + actPrevious.lenData))) {
                                // Insertions must be immediately after to coalesce
                                currentAction++;
                        } else if (!actions[currentAction].mayCoalesce) {
                                // Not allowed to coalesce if this set
                                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;
        actions[currentAction].Create(at, position, data, lengthData);
        currentAction++;
        actions[currentAction].Create(startAction);
        maxAction = currentAction;
}

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;
}

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

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

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 (actions[currentAction].at == startAction && currentAction < maxAction)
                currentAction++;

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

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

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

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

CellBuffer::~CellBuffer() {
}

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

void CellBuffer::GetCharRange(char *buffer, int position, int lengthRetrieve) {
        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;
        }
        
        for (int i=0; i<lengthRetrieve; i++) {
                *buffer++ = substance.ValueAt(position + i);
        }
}

char CellBuffer::StyleAt(int position) {
        return style.ValueAt(position);
}

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

// The char* returned is to an allocation owned by the undo history
const char *CellBuffer::InsertString(int position, const char *s, int insertLength, bool &startSequence) {
        char *data = 0;
        // InsertString and DeleteChars are the bottleneck though which all changes occur
        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 = new char[insertLength];
                        for (int i = 0; i < insertLength; i++) {
                                data[i] = s[i];
                        }
                        uh.AppendAction(insertAction, position, data, insertLength, startSequence);
                }

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

bool CellBuffer::SetStyleAt(int position, char styleValue, char mask) {
        styleValue &= mask;
        char curVal = style.ValueAt(position);
        if ((curVal & mask) != styleValue) {
                style.SetValueAt(position, static_cast<char>((curVal & ~mask) | styleValue));
                return true;
        } else {
                return false;
        }
}

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

// The char* returned is to an allocation owned by the undo history
const char *CellBuffer::DeleteChars(int position, int deleteLength, bool &startSequence) {
        // InsertString and DeleteChars are the bottleneck though which all changes occur
        PLATFORM_ASSERT(deleteLength > 0);
        char *data = 0;
        if (!readOnly) {
                if (collectingUndo) {
                        // Save into the undo/redo stack, but only the characters - not the formatting
                        data = new char[deleteLength];
                        for (int i = 0; i < deleteLength; i++) {
                                data[i] = substance.ValueAt(position + i);
                        }
                        uh.AppendAction(removeAction, position, data, deleteLength, startSequence);
                }

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

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

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

int CellBuffer::Lines() const {
        return lv.Lines();
}

int CellBuffer::LineStart(int line) const {
        if (line < 0)
                return 0;
        else if (line >= Lines())
                return Length();
        else
                return lv.LineStart(line);
}

bool CellBuffer::IsReadOnly() {
        return readOnly;
}

void CellBuffer::SetReadOnly(bool set) {
        readOnly = set;
}

void CellBuffer::SetSavePoint() {
        uh.SetSavePoint();
}

bool CellBuffer::IsSavePoint() {
        return uh.IsSavePoint();
}

int CellBuffer::AddMark(int line, int markerNum) {
        if ((line >= 0) && (line < Lines())) {
                return lv.AddMark(line, markerNum);
        }
        return - 1;
}

void CellBuffer::DeleteMark(int line, int markerNum) {
        if ((line >= 0) && (line < Lines())) {
                lv.DeleteMark(line, markerNum, false);
        }
}

void CellBuffer::DeleteMarkFromHandle(int markerHandle) {
        lv.DeleteMarkFromHandle(markerHandle);
}

int CellBuffer::GetMark(int line) {
        if ((line >= 0) && (line < Lines()))
                return lv.MarkValue(line);
        return 0;
}

void CellBuffer::DeleteAllMarks(int markerNum) {
        for (int line = 0; line < Lines(); line++) {
                lv.DeleteMark(line, markerNum, true);
        }
}

int CellBuffer::LineFromHandle(int markerHandle) {
        return lv.LineFromHandle(markerHandle);
}

// Without undo

void CellBuffer::InsertLine(int line, int position) {
        lv.InsertLine(line, position);
        if (lineStates.Length()) {
                lineStates.EnsureLength(line);
                lineStates.Insert(line, 0);
        }
}

void CellBuffer::RemoveLine(int line) {
        lv.RemoveLine(line);
        if (lineStates.Length() > line) {
                lineStates.Delete(line);
        }
}

void CellBuffer::BasicInsertString(int position, const char *s, int insertLength) {
        if (insertLength == 0)
                return;
        PLATFORM_ASSERT(insertLength > 0);

        substance.InsertFromArray(position, s, 0, insertLength);
        style.InsertValue(position, insertLength, 0);

        int lineInsert = lv.LineFromPosition(position) + 1;
        // Point all the lines after the insertion point further along in the buffer
        lv.InsertText(lineInsert-1, insertLength);
        char chPrev = substance.ValueAt(position - 1);
        char chAfter = substance.ValueAt(position + insertLength);
        if (chPrev == '\r' && chAfter == '\n') {
                // Splitting up a crlf pair at position
                InsertLine(lineInsert, position);
                lineInsert++;
        }
        char ch = ' ';
        for (int i = 0; i < insertLength; i++) {
                ch = s[i];
                if (ch == '\r') {
                        InsertLine(lineInsert, (position + i) + 1);
                        lineInsert++;
                } else if (ch == '\n') {
                        if (chPrev == '\r') {
                                // Patch up what was end of line
                                lv.SetLineStart(lineInsert - 1, (position + i) + 1);
                        } else {
                                InsertLine(lineInsert, (position + i) + 1);
                                lineInsert++;
                        }
                }
                chPrev = ch;
        }
        // Joining two lines where last insertion is cr and following substance starts with lf
        if (chAfter == '\n') {
                if (ch == '\r') {
                        // End of line already in buffer so drop the newly created one
                        RemoveLine(lineInsert - 1);
                }
        }
}

void CellBuffer::BasicDeleteChars(int position, int deleteLength) {
        if (deleteLength == 0)
                return;

        if ((position == 0) && (deleteLength == substance.Length())) {
                // If whole buffer is being deleted, faster to reinitialise lines data
                // than to delete each line.
                lv.Init();
        } else {
                // Have to fix up line positions before doing deletion as looking at text in buffer
                // to work out which lines have been removed

                int lineRemove = lv.LineFromPosition(position) + 1;
                lv.InsertText(lineRemove-1, - (deleteLength));
                char chPrev = substance.ValueAt(position - 1);
                char chBefore = chPrev;
                char chNext = substance.ValueAt(position);
                bool ignoreNL = false;
                if (chPrev == '\r' && chNext == '\n') {
                        // Move back one
                        lv.SetLineStart(lineRemove, position);
                        lineRemove++;
                        ignoreNL = true;        // First \n is not real deletion
                }

                char ch = chNext;
                for (int i = 0; i < deleteLength; i++) {
                        chNext = substance.ValueAt(position + i + 1);
                        if (ch == '\r') {
                                if (chNext != '\n') {
                                        RemoveLine(lineRemove);
                                }
                        } else if (ch == '\n') {
                                if (ignoreNL) {
                                        ignoreNL = false;       // Further \n are real deletions
                                } else {
                                        RemoveLine(lineRemove);
                                }
                        }

                        ch = chNext;
                }
                // May have to fix up end if last deletion causes cr to be next to lf
                // or removes one of a crlf pair
                char chAfter = substance.ValueAt(position + deleteLength);
                if (chBefore == '\r' && chAfter == '\n') {
                        // Using lineRemove-1 as cr ended line before start of deletion
                        RemoveLine(lineRemove - 1);
                        lv.SetLineStart(lineRemove - 1, position + 1);
                }
        }
        substance.DeleteRange(position, deleteLength);
        style.DeleteRange(position, deleteLength);
}

bool CellBuffer::SetUndoCollection(bool collectUndo) {
        collectingUndo = collectUndo;
        uh.DropUndoSequence();
        return collectingUndo;
}

bool CellBuffer::IsCollectingUndo() {
        return collectingUndo;
}

void CellBuffer::BeginUndoAction() {
        uh.BeginUndoAction();
}

void CellBuffer::EndUndoAction() {
        uh.EndUndoAction();
}

void CellBuffer::DeleteUndoHistory() {
        uh.DeleteUndoHistory();
}

bool CellBuffer::CanUndo() {
        return uh.CanUndo();
}

int CellBuffer::StartUndo() {
        return uh.StartUndo();
}

const Action &CellBuffer::GetUndoStep() const {
        return uh.GetUndoStep();
}

void CellBuffer::PerformUndoStep() {
        const Action &actionStep = uh.GetUndoStep();
        if (actionStep.at == insertAction) {
                BasicDeleteChars(actionStep.position, actionStep.lenData);
        } else if (actionStep.at == removeAction) {
                BasicInsertString(actionStep.position, actionStep.data, actionStep.lenData);
        }
        uh.CompletedUndoStep();
}

bool CellBuffer::CanRedo() {
        return uh.CanRedo();
}

int CellBuffer::StartRedo() {
        return uh.StartRedo();
}

const Action &CellBuffer::GetRedoStep() const {
        return uh.GetRedoStep();
}

void CellBuffer::PerformRedoStep() {
        const Action &actionStep = uh.GetRedoStep();
        if (actionStep.at == insertAction) {
                BasicInsertString(actionStep.position, actionStep.data, actionStep.lenData);
        } else if (actionStep.at == removeAction) {
                BasicDeleteChars(actionStep.position, actionStep.lenData);
        }
        uh.CompletedRedoStep();
}

int CellBuffer::SetLineState(int line, int state) {
        lineStates.EnsureLength(line + 1);
        int stateOld = lineStates[line];
        lineStates[line] = state;
        return stateOld;
}

int CellBuffer::GetLineState(int line) {
        lineStates.EnsureLength(line + 1);
        return lineStates[line];
}

int CellBuffer::GetMaxLineState() {
        return lineStates.Length();
}

int CellBuffer::SetLevel(int line, int level) {
        return lv.SetLevel(line, level);
}

int CellBuffer::GetLevel(int line) {
        return lv.GetLevel(line);
}

void CellBuffer::ClearLevels() {
        lv.ClearLevels();
}