OK this kills the Undo * thing in favour of boost::shared_ptr. It's
valgrind clean, and seems to work fine for me. Getting undo_funcs.C into
readable shape is a job for another day.
I've not included boring parts of the patch like removal of undostack
files
OK to apply ?
thanks
john
--
"Time is a great teacher, but unfortunately it kills all its pupils."
- Hector Louis Berlioz
Index: src/undo_funcs.h
===================================================================
RCS file: /usr/local/lyx/cvsroot/lyx-devel/src/undo_funcs.h,v
retrieving revision 1.2
diff -u -r1.2 undo_funcs.h
--- src/undo_funcs.h 21 Mar 2002 17:25:32 -0000 1.2
+++ src/undo_funcs.h 26 May 2002 18:58:05 -0000
@@ -25,8 +25,6 @@
extern bool textUndo(BufferView *);
/// returns false if no redo possible
extern bool textRedo(BufferView *);
-/// used by TextUndo/TextRedo
-extern bool textHandleUndo(BufferView *, Undo * undo);
/// makes sure the next operation will be stored
extern void finishUndo();
/// this is dangerous and for internal use only
@@ -40,9 +38,6 @@
extern void setRedo(BufferView *, Undo::undo_kind kind,
Paragraph const * first, Paragraph const * behind);
///
-extern Undo * createUndo(BufferView *, Undo::undo_kind kind,
- Paragraph const * first, Paragraph const * behind);
-/// for external use in lyx_cb.C
extern void setCursorParUndo(BufferView *);
// returns a pointer to the very first Paragraph depending of where we are
@@ -53,8 +48,6 @@
///
extern LyXCursor const & undoCursor(BufferView * bv);
-/// the flag used by FinishUndo();
-extern bool undo_finished;
/// a flag
extern bool undo_frozen;
Index: src/undo_funcs.C
===================================================================
RCS file: /usr/local/lyx/cvsroot/lyx-devel/src/undo_funcs.C,v
retrieving revision 1.23
diff -u -r1.23 undo_funcs.C
--- src/undo_funcs.C 24 May 2002 10:37:46 -0000 1.23
+++ src/undo_funcs.C 26 May 2002 18:58:05 -0000
@@ -23,328 +23,212 @@
#include "iterators.h"
-#define DELETE_UNUSED_PARAGRAPHS 1
-#ifdef DELETE_UNUSED_PARAGRAPHS
#include <vector>
-#endif
using std::vector;
+using boost::shared_ptr;
/// the flag used by FinishUndo();
bool undo_finished;
-/// a flag
+/// FIXME
bool undo_frozen;
+namespace {
-bool textUndo(BufferView * bv)
+void finishNoUndo(BufferView * bv)
{
- // returns false if no undo possible
- Undo * undo = bv->buffer()->undostack.top();
- bv->buffer()->undostack.pop();
- if (undo) {
- finishUndo();
- if (!undo_frozen) {
- Paragraph * first =
bv->buffer()->getParFromID(undo->number_of_before_par);
- if (first && first->next())
- first = first->next();
- else if (!first)
- first = firstUndoParagraph(bv,
undo->number_of_inset_id);
- if (first) {
- bv->buffer()->redostack.push(
- createUndo(bv, undo->kind, first,
-
bv->buffer()->getParFromID(undo->number_of_behind_par)));
- }
- }
- }
- // now we can unlock the inset for saftey because the inset pointer could
- // be changed during the undo-function. Anyway if needed we have to lock
- // the right inset/position if this is requested.
freezeUndo();
bv->unlockInset(bv->theLockingInset());
- bool ret = textHandleUndo(bv, undo);
+ finishUndo();
+ bv->text->status(bv, LyXText::NEED_MORE_REFRESH);
unFreezeUndo();
- return ret;
}
-
-
-bool textRedo(BufferView * bv)
+
+
+// returns false if no undo possible
+bool textHandleUndo(BufferView * bv, Undo & undo)
{
- // returns false if no redo possible
- Undo * undo = bv->buffer()->redostack.top();
- bv->buffer()->redostack.pop();
- if (undo) {
- finishUndo();
- if (!undo_frozen) {
- Paragraph * first =
bv->buffer()->getParFromID(undo->number_of_before_par);
- if (first && first->next())
- first = first->next();
- else if (!first)
- first = firstUndoParagraph(bv,
undo->number_of_inset_id);
- if (first) {
- bv->buffer()->undostack.push(
- createUndo(bv, undo->kind, first,
-
bv->buffer()->getParFromID(undo->number_of_behind_par)));
+ Buffer * b = bv->buffer();
+
+ Paragraph * before =
+ b->getParFromID(undo.number_of_before_par);
+ Paragraph * behind =
+ b->getParFromID(undo.number_of_behind_par);
+ Paragraph * tmppar;
+ Paragraph * tmppar2;
+ Paragraph * tmppar5;
+
+ // if there's no before take the beginning
+ // of the document for redoing
+ if (!before) {
+ LyXText * t = bv->text;
+ int num = undo.number_of_inset_id;
+ if (undo.number_of_inset_id >= 0) {
+ Inset * in = bv->buffer()->getInsetFromID(num);
+ if (in) {
+ t = in->getLyXText(bv);
+ } else {
+ num = -1;
}
}
+ t->setCursorIntern(bv, firstUndoParagraph(bv, num), 0);
}
- // now we can unlock the inset for saftey because the inset pointer could
- // be changed during the undo-function. Anyway if needed we have to lock
- // the right inset/position if this is requested.
- freezeUndo();
- bv->unlockInset(bv->theLockingInset());
- bool ret = textHandleUndo(bv, undo);
- unFreezeUndo();
- return ret;
-}
-
-
-bool textHandleUndo(BufferView * bv, Undo * undo)
-{
- // returns false if no undo possible
- bool result = false;
- if (undo) {
- Paragraph * before =
- bv->buffer()->getParFromID(undo->number_of_before_par);
- Paragraph * behind =
- bv->buffer()->getParFromID(undo->number_of_behind_par);
- Paragraph * tmppar;
- Paragraph * tmppar2;
- Paragraph * tmppar5;
-
- // if there's no before take the beginning
- // of the document for redoing
- if (!before) {
- LyXText * t = bv->text;
- int num = undo->number_of_inset_id;
- if (undo->number_of_inset_id >= 0) {
- Inset * in = bv->buffer()->getInsetFromID(num);
- if (in) {
- t = in->getLyXText(bv);
- } else {
- num = -1;
- }
- }
- t->setCursorIntern(bv, firstUndoParagraph(bv, num), 0);
- }
- // replace the paragraphs with the undo informations
+ // replace the paragraphs with the undo informations
- Paragraph * tmppar3 = undo->par;
- undo->par = 0; /* otherwise the undo destructor would
- delete the paragraph */
-
- // get last undo par and set the right(new) inset-owner of the
- // paragraph if there is any. This is not needed if we don't have
- // a paragraph before because then in is automatically done in the
- // function which assigns the first paragraph to an InsetText. (Jug)
- Paragraph * tmppar4 = tmppar3;
- if (tmppar4) {
- Inset * in = 0;
- if (before)
- in = before->inInset();
- else if (undo->number_of_inset_id >= 0)
- in =
bv->buffer()->getInsetFromID(undo->number_of_inset_id);
+ Paragraph * tmppar3 = undo.par;
+ undo.par = 0; /* otherwise the undo destructor would
+ delete the paragraph */
+
+ // get last undo par and set the right(new) inset-owner of the
+ // paragraph if there is any. This is not needed if we don't have
+ // a paragraph before because then in is automatically done in the
+ // function which assigns the first paragraph to an InsetText. (Jug)
+ Paragraph * tmppar4 = tmppar3;
+ if (tmppar4) {
+ Inset * in = 0;
+ if (before)
+ in = before->inInset();
+ else if (undo.number_of_inset_id >= 0)
+ in = bv->buffer()->getInsetFromID(undo.number_of_inset_id);
+ tmppar4->setInsetOwner(in);
+ while (tmppar4->next()) {
+ tmppar4 = tmppar4->next();
tmppar4->setInsetOwner(in);
- while (tmppar4->next()) {
- tmppar4 = tmppar4->next();
- tmppar4->setInsetOwner(in);
- }
}
+ }
- // now remove the old text if there is any
-#ifdef DELETE_UNUSED_PARAGRAPHS
- vector<Paragraph *> vvpar;
-#endif
- if (before != behind || (!behind && !before)) {
- if (before)
- tmppar5 = before->next();
- else
- tmppar5 = firstUndoParagraph(bv,
undo->number_of_inset_id);
- tmppar2 = tmppar3;
- while (tmppar5 && tmppar5 != behind) {
-#ifdef DELETE_UNUSED_PARAGRAPHS
- vvpar.push_back(tmppar5);
-#endif
- tmppar = tmppar5;
- tmppar5 = tmppar5->next();
- // a memory optimization for edit:
- // Only layout information
- // is stored in the undo. So restore
- // the text informations.
- if (undo->kind == Undo::EDIT) {
- tmppar2->setContentsFromPar(tmppar);
-#ifndef DELETE_UNUSED_PARAGRAPHS
- tmppar->clearContents();
-#endif
- tmppar2 = tmppar2->next();
- }
+ // now remove the old text if there is any
+ vector<Paragraph *> vvpar;
+ if (before != behind || (!behind && !before)) {
+ if (before)
+ tmppar5 = before->next();
+ else
+ tmppar5 = firstUndoParagraph(bv, undo.number_of_inset_id);
+ tmppar2 = tmppar3;
+ while (tmppar5 && tmppar5 != behind) {
+ vvpar.push_back(tmppar5);
+ tmppar = tmppar5;
+ tmppar5 = tmppar5->next();
+
+ // a memory optimization for edit:
+ // Only layout information
+ // is stored in the undo. So restore
+ // the text informations.
+ if (undo.kind == Undo::EDIT) {
+ tmppar2->setContentsFromPar(tmppar);
+ tmppar2 = tmppar2->next();
}
}
+ }
- // put the new stuff in the list if there is one
- if (tmppar3) {
- if (before)
- before->next(tmppar3);
- else
- bv->text->ownerParagraph(firstUndoParagraph(bv,
undo->number_of_inset_id)->id(),
- tmppar3);
-
- tmppar3->previous(before);
- } else {
- // We enter here on DELETE undo operations where we have to
- // substitue the second paragraph with the first if the removed
- // one is the first!
- if (!before && behind) {
- bv->text->ownerParagraph(firstUndoParagraph(bv,
undo->number_of_inset_id)->id(),
- behind);
- tmppar3 = behind;
- }
- }
- if (tmppar4) {
- tmppar4->next(behind);
- if (behind)
- behind->previous(tmppar4);
+ // put the new stuff in the list if there is one
+ if (tmppar3) {
+ if (before)
+ before->next(tmppar3);
+ else
+ bv->text->ownerParagraph(firstUndoParagraph(bv,
+undo.number_of_inset_id)->id(),
+ tmppar3);
+
+ tmppar3->previous(before);
+ } else {
+ // We enter here on DELETE undo operations where we have to
+ // substitue the second paragraph with the first if the removed
+ // one is the first!
+ if (!before && behind) {
+ bv->text->ownerParagraph(firstUndoParagraph(bv,
+undo.number_of_inset_id)->id(),
+ behind);
+ tmppar3 = behind;
}
+ }
+ if (tmppar4) {
+ tmppar4->next(behind);
+ if (behind)
+ behind->previous(tmppar4);
+ }
- // Set the cursor for redoing
- if (before) {
- Inset * it = before->inInset();
- if (it)
- it->getLyXText(bv)->setCursorIntern(bv, before, 0);
- else
- bv->text->setCursorIntern(bv, before, 0);
- }
+ // Set the cursor for redoing
+ if (before) {
+ Inset * it = before->inInset();
+ if (it)
+ it->getLyXText(bv)->setCursorIntern(bv, before, 0);
+ else
+ bv->text->setCursorIntern(bv, before, 0);
+ }
- Paragraph * endpar = 0;
- // calculate the endpar for redoing the paragraphs.
- if (behind)
- endpar = behind->next();
+ Paragraph * endpar = 0;
+ // calculate the endpar for redoing the paragraphs.
+ if (behind)
+ endpar = behind->next();
- tmppar = bv->buffer()->getParFromID(undo->number_of_cursor_par);
- UpdatableInset* it = 0;
- if (tmppar3)
- it = static_cast<UpdatableInset*>(tmppar3->inInset());
- if (it) {
- it->getLyXText(bv)->redoParagraphs(bv,
- it->getLyXText(bv)->cursor,
- endpar);
- if (tmppar) {
- it = static_cast<UpdatableInset*>(tmppar->inInset());
- LyXText * t;
- if (it) {
- it->edit(bv);
- t = it->getLyXText(bv);
- } else {
- t = bv->text;
- }
- t->setCursorIntern(bv, tmppar, undo->cursor_pos);
- // clear any selection and set the selection cursor
- // for an evt. new selection.
- t->clearSelection();
- t->selection.cursor = t->cursor;
- t->updateCounters(bv, t->cursor.row());
- bv->fitCursor();
+ tmppar = bv->buffer()->getParFromID(undo.number_of_cursor_par);
+ UpdatableInset* it = 0;
+ if (tmppar3)
+ it = static_cast<UpdatableInset*>(tmppar3->inInset());
+ if (it) {
+ it->getLyXText(bv)->redoParagraphs(bv,
+ it->getLyXText(bv)->cursor,
+ endpar);
+ if (tmppar) {
+ it = static_cast<UpdatableInset*>(tmppar->inInset());
+ LyXText * t;
+ if (it) {
+ it->edit(bv);
+ t = it->getLyXText(bv);
+ } else {
+ t = bv->text;
}
- bv->updateInset(it, false);
- bv->text->setCursorIntern(bv, bv->text->cursor.par(),
- bv->text->cursor.pos());
- } else {
- bv->text->redoParagraphs(bv, bv->text->cursor, endpar);
- if (tmppar) {
- LyXText * t;
- Inset * it = tmppar->inInset();
- if (it) {
- it->edit(bv);
- t = it->getLyXText(bv);
- } else {
- t = bv->text;
- }
- t->setCursorIntern(bv, tmppar, undo->cursor_pos);
- // clear any selection and set the selection cursor
- // for an evt. new selection.
- t->clearSelection();
- t->selection.cursor = t->cursor;
- t->updateCounters(bv, t->cursor.row());
+ t->setCursorIntern(bv, tmppar, undo.cursor_pos);
+ // clear any selection and set the selection cursor
+ // for an evt. new selection.
+ t->clearSelection();
+ t->selection.cursor = t->cursor;
+ t->updateCounters(bv, t->cursor.row());
+ bv->fitCursor();
+ }
+ bv->updateInset(it, false);
+ bv->text->setCursorIntern(bv, bv->text->cursor.par(),
+ bv->text->cursor.pos());
+ } else {
+ bv->text->redoParagraphs(bv, bv->text->cursor, endpar);
+ if (tmppar) {
+ LyXText * t;
+ Inset * it = tmppar->inInset();
+ if (it) {
+ it->edit(bv);
+ t = it->getLyXText(bv);
+ } else {
+ t = bv->text;
}
+ t->setCursorIntern(bv, tmppar, undo.cursor_pos);
+ // clear any selection and set the selection cursor
+ // for an evt. new selection.
+ t->clearSelection();
+ t->selection.cursor = t->cursor;
+ t->updateCounters(bv, t->cursor.row());
}
- result = true;
- delete undo;
-#ifdef DELETE_UNUSED_PARAGRAPHS
- // And here it's save enough to delete all removed paragraphs
- vector<Paragraph *>::iterator pit = vvpar.begin();
- if (pit != vvpar.end()) {
-#if 0
- lyxerr << endl << "PARS BEFORE:";
- ParIterator end = bv->buffer()->par_iterator_end();
- ParIterator it = bv->buffer()->par_iterator_begin();
- for (; it != end; ++it)
- lyxerr << (*it)->previous() << "<- " << (*it) << " ->"
<< (*it)->next() << endl;
- lyxerr << "DEL: ";
-#endif
+ }
+
+ // And here it's save enough to delete all removed paragraphs
+ vector<Paragraph *>::iterator pit = vvpar.begin();
+ if (pit != vvpar.end()) {
for(;pit != vvpar.end(); ++pit) {
-// lyxerr << *pit << " ";
(*pit)->previous(0);
(*pit)->next(0);
delete (*pit);
}
-#if 0
- lyxerr << endl << "PARS AFTER:";
- end = bv->buffer()->par_iterator_end();
- it = bv->buffer()->par_iterator_begin();
- for (; it != end; ++it)
- lyxerr << (*it)->previous() << "<- " << (*it) << " ->"
<< (*it)->next() << endl;
-#endif
}
-#endif
- }
+
finishUndo();
bv->text->status(bv, LyXText::NEED_MORE_REFRESH);
- return result;
-}
-
-
-void finishUndo()
-{
- // makes sure the next operation will be stored
- undo_finished = true;
-}
-
-
-void freezeUndo()
-{
- // this is dangerous and for internal use only
- undo_frozen = true;
-}
-
-
-void unFreezeUndo()
-{
- // this is dangerous and for internal use only
- undo_frozen = false;
-}
-
-
-void setUndo(BufferView * bv, Undo::undo_kind kind,
- Paragraph const * first, Paragraph const * behind)
-{
- if (!undo_frozen) {
- bv->buffer()->undostack.push(createUndo(bv, kind, first, behind));
- bv->buffer()->redostack.clear();
- }
-}
-
-
-void setRedo(BufferView * bv, Undo::undo_kind kind,
- Paragraph const * first, Paragraph const * behind)
-{
- bv->buffer()->redostack.push(createUndo(bv, kind, first, behind));
+ return true;
}
-
-Undo * createUndo(BufferView * bv, Undo::undo_kind kind,
- Paragraph const * first, Paragraph const * behind)
+
+bool createUndo(BufferView * bv, Undo::undo_kind kind,
+ Paragraph const * first, Paragraph const * behind, shared_ptr<Undo> & u)
{
lyx::Assert(first);
@@ -359,6 +243,8 @@
if (first->inInset())
inset_id = first->inInset()->id();
+ Buffer * b = bv->buffer();
+
// Undo::EDIT and Undo::FINISH are
// always finished. (no overlapping there)
// overlapping only with insert and delete inside one paragraph:
@@ -367,15 +253,16 @@
// EDIT is special since only layout information, not the
// contents of a paragaph are stored.
if (!undo_finished && (kind != Undo::EDIT) && (kind != Undo::FINISH)) {
- // check wether storing is needed
- if (!bv->buffer()->undostack.empty() &&
- bv->buffer()->undostack.top()->kind == kind &&
- bv->buffer()->undostack.top()->number_of_before_par ==
before_number &&
- bv->buffer()->undostack.top()->number_of_behind_par ==
behind_number) {
+ // check whether storing is needed
+ if (!b->undostack.empty() &&
+ b->undostack.top()->kind == kind &&
+ b->undostack.top()->number_of_before_par == before_number &&
+ b->undostack.top()->number_of_behind_par == behind_number) {
// no undo needed
- return 0;
+ return false;
}
}
+
// create a new Undo
Paragraph * undopar;
@@ -428,12 +315,133 @@
int cursor_par = undoCursor(bv).par()->id();
int cursor_pos = undoCursor(bv).pos();
- Undo * undo = new Undo(kind, inset_id,
- before_number, behind_number,
- cursor_par, cursor_pos, undopar);
+ u.reset(new Undo(kind, inset_id,
+ before_number, behind_number,
+ cursor_par, cursor_pos, undopar));
undo_finished = false;
- return undo;
+ return true;
+}
+
+} // namespace anon
+
+void finishUndo()
+{
+ // makes sure the next operation will be stored
+ undo_finished = true;
+}
+
+
+void freezeUndo()
+{
+ // this is dangerous and for internal use only
+ undo_frozen = true;
+}
+
+
+void unFreezeUndo()
+{
+ // this is dangerous and for internal use only
+ undo_frozen = false;
+}
+
+
+// returns false if no undo possible
+bool textUndo(BufferView * bv)
+{
+ Buffer * b = bv->buffer();
+
+ if (b->undostack.empty()) {
+ finishNoUndo(bv);
+ return false;
+ }
+
+ shared_ptr<Undo> undo = b->undostack.top();
+ b->undostack.pop();
+ finishUndo();
+
+ if (!undo_frozen) {
+ Paragraph * first = b->getParFromID(undo->number_of_before_par);
+ if (first && first->next())
+ first = first->next();
+ else if (!first)
+ first = firstUndoParagraph(bv, undo->number_of_inset_id);
+ if (first) {
+ shared_ptr<Undo> u;
+ if (createUndo(bv, undo->kind, first,
+ b->getParFromID(undo->number_of_behind_par), u))
+ b->redostack.push(u);
+ }
+ }
+
+ // now we can unlock the inset for saftey because the inset pointer could
+ // be changed during the undo-function. Anyway if needed we have to lock
+ // the right inset/position if this is requested.
+ freezeUndo();
+ bv->unlockInset(bv->theLockingInset());
+ bool const ret = textHandleUndo(bv, *undo.get());
+ unFreezeUndo();
+ return ret;
+}
+
+
+// returns false if no redo possible
+bool textRedo(BufferView * bv)
+{
+ Buffer * b = bv->buffer();
+
+ if (b->redostack.empty()) {
+ finishNoUndo(bv);
+ return false;
+ }
+
+ shared_ptr<Undo> undo = b->redostack.top();
+ b->redostack.pop();
+ finishUndo();
+
+ if (!undo_frozen) {
+ Paragraph * first = bv->buffer()->getParFromID(undo->number_of_before_par);
+ if (first && first->next())
+ first = first->next();
+ else if (!first)
+ first = firstUndoParagraph(bv, undo->number_of_inset_id);
+ if (first) {
+ shared_ptr<Undo> u;
+ if (createUndo(bv, undo->kind, first,
+
+bv->buffer()->getParFromID(undo->number_of_behind_par), u))
+ bv->buffer()->undostack.push(u);
+ }
+ }
+
+ // now we can unlock the inset for saftey because the inset pointer could
+ // be changed during the undo-function. Anyway if needed we have to lock
+ // the right inset/position if this is requested.
+ freezeUndo();
+ bv->unlockInset(bv->theLockingInset());
+ bool ret = textHandleUndo(bv, *undo.get());
+ unFreezeUndo();
+ return ret;
+}
+
+
+void setUndo(BufferView * bv, Undo::undo_kind kind,
+ Paragraph const * first, Paragraph const * behind)
+{
+ if (!undo_frozen) {
+ shared_ptr<Undo> u;
+ if (createUndo(bv, kind, first, behind, u))
+ bv->buffer()->undostack.push(u);
+ bv->buffer()->redostack.clear();
+ }
+}
+
+
+void setRedo(BufferView * bv, Undo::undo_kind kind,
+ Paragraph const * first, Paragraph const * behind)
+{
+ shared_ptr<Undo> u;
+ if (createUndo(bv, kind, first, behind, u))
+ bv->buffer()->redostack.push(u);
}
Index: src/buffer.h
===================================================================
RCS file: /usr/local/lyx/cvsroot/lyx-devel/src/buffer.h,v
retrieving revision 1.97
diff -u -r1.97 buffer.h
--- src/buffer.h 22 May 2002 12:33:02 -0000 1.97
+++ src/buffer.h 26 May 2002 18:58:05 -0000
@@ -19,12 +19,15 @@
#include "LString.h"
#include "undo.h"
-#include "undostack.h"
+#include "support/limited_stack.h"
+
#include "lyxvc.h"
#include "bufferparams.h"
#include "texrow.h"
#include "paragraph.h"
+#include <boost/shared_ptr.hpp>
+
class BufferView;
class LyXRC;
class TeXErrors;
@@ -298,11 +301,11 @@
bool isMultiLingual();
/// Does this mean that this is buffer local?
- UndoStack undostack;
-
- /// Does this mean that this is buffer local?
- UndoStack redostack;
-
+ limited_stack<boost::shared_ptr<Undo> > undostack;
+
+ /// Does this mean that this is buffer local?
+ limited_stack<boost::shared_ptr<Undo> > redostack;
+
///
BufferParams params;
Index: src/support/limited_stack.h
===================================================================
RCS file: src/support/limited_stack.h
diff -N src/support/limited_stack.h
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ src/support/limited_stack.h 26 May 2002 18:58:05 -0000
@@ -0,0 +1,77 @@
+// -*- C++ -*-
+/**
+ * \file limited_stack.h
+ * Copyright 2002 the LyX Team
+ * Read the file COPYING
+ *
+ * \author John Levon <[EMAIL PROTECTED]>
+ */
+
+#ifndef LIMITED_STACK_H
+#define LIMITED_STACK_H
+
+#include <list>
+
+#include <boost/shared_ptr.hpp>
+
+/**
+ * limited_stack - a stack of limited size
+ *
+ * Like a normal stack, but only accepts pointer types,
+ * and bottom elements are deleted on overflow
+ */
+template <typename T>
+class limited_stack {
+public:
+ typedef std::list<T> container_type;
+ typedef typename container_type::value_type value_type;
+ typedef typename container_type::size_type size_type;
+
+ /// limit is the maximum size of the stack
+ limited_stack(size_type limit = 10) {
+ limit_ = limit;
+ }
+
+ /// return the top element
+ value_type top() {
+ return c_.front();
+ }
+
+ /// pop and throw away the top element
+ void pop() {
+ c_.pop_front();
+ }
+
+ /// return true if the stack is empty
+ bool empty() const {
+ return c_.size() == 0;
+ }
+
+ /// clear all elements, deleting them
+ void clear() {
+ while (!c_.empty()) {
+ c_.pop_back();
+ }
+ }
+
+ /// push an item on to the stack, deleting the
+ /// bottom item on overflow.
+ void push(value_type const & v) {
+ c_.push_front(v);
+ if (c_.size() > limit_) {
+ c_.pop_back();
+ }
+ }
+
+private:
+ /// internal contents
+ container_type c_;
+ /// the maximum number elements stored
+ size_type limit_;
+};
+
+// make pointer type an error.
+template <typename T>
+class limited_stack<T*>;
+
+#endif // LIMITED_STACK_H
