//
// "$Id$"
//
// Copyright 2001-2009 by Bill Spitzak and others.
// Original code Copyright Mark Edel.  Permission to distribute under
// the LGPL for the FLTK library granted by Mark Edel.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems on the following page:
//
//     http://www.fltk.org/str.php
//

#include <stdio.h>
#include <stdlib.h>
#include <FL/fl_utf8.h>
#include "flstring.h"
#include <ctype.h>
#include <FL/Fl.H>
#include <FL/Fl_Text_Buffer.H>


/*
 This file is based on a port of NEdit to FLTK many years ago. NEdit at that
 point was already stretched beyond the task it was designed for which explains
 why the source code is sometimes pretty convoluted. It still is a very useful
 widget for FLTK, and we are thankful that the nedit team allowed us to 
 integrate their code.

 With the introduction of Unicode and UTF-8, Fl_Text_... has to go into a whole
 new generation of code. Originally designed for monspaced fonts only, many
 features make les sense in the multibyte and multiwdth world of UTF-8.
 
 Columns are a good example. There is simply no such thing. The new Fl_Text_...
 widget converts columns to pixels by multiplying them with the average 
 character width for a given font 
 
 Rectangular selections were rearely used (if at all) and make little sense when
 using variable width fonts. They have been removed.
 
 Using multiple spaces to emulate tab stops has been replaced by pixel counting
 routines. They are slower, but give the expected result for proportional fonts.
 
 And constantly recalculating character widths is just much too expensive. Lines
 of text are now subdivided into blocks of text which are measured at once 
 instead of individual characters. 
 */


#ifndef min

/*
 Unicode safe.
 */
static int max(int i1, int i2)
{
  return i1 >= i2 ? i1 : i2;
}

/*
 Unicode safe.
 */
static int min(int i1, int i2)
{
  return i1 <= i2 ? i1 : i2;
}

#endif


static char *undobuffer;
static int undobufferlength;
static Fl_Text_Buffer *undowidget;
static int undoat;		// points after insertion
static int undocut;		// number of characters deleted there
static int undoinsert;		// number of characters inserted
static int undoyankcut;		// length of valid contents of buffer, even if undocut=0

/*
 Resize the undo buffer to match at least the requested size.
 Unicode safe.
 */
static void undobuffersize(int n)
{
  if (n > undobufferlength) {
    if (undobuffer) {
      do {
	undobufferlength *= 2;
      } while (undobufferlength < n);
      undobuffer = (char *) realloc(undobuffer, undobufferlength);
    } else {
      undobufferlength = n + 9;
      undobuffer = (char *) malloc(undobufferlength);
    }
  }
}


/*
 Initialize all variables.
 Unicode safe.
 */
Fl_Text_Buffer::Fl_Text_Buffer(int requestedSize, int preferredGapSize)
{
  mLength = 0;
  mPreferredGapSize = preferredGapSize;
  mBuf = (char *) malloc(requestedSize + mPreferredGapSize);
  mGapStart = 0;
  mGapEnd = mPreferredGapSize;
  mTabDist = 8;
  mPrimary.mSelected = 0;
  mPrimary.mStart = mPrimary.mEnd = 0;
  mSecondary.mSelected = 0;
  mSecondary.mStart = mSecondary.mEnd = 0;
  mHighlight.mSelected = 0;
  mHighlight.mStart = mHighlight.mEnd = 0;
  mModifyProcs = NULL;
  mCbArgs = NULL;
  mNModifyProcs = 0;
  mNPredeleteProcs = 0;
  mPredeleteProcs = NULL;
  mPredeleteCbArgs = NULL;
  mCursorPosHint = 0;
  mCanUndo = 1;
  }


/*
 Free all resources.
 Unicode safe.
 */
Fl_Text_Buffer::~Fl_Text_Buffer()
{
  free(mBuf);
  if (mNModifyProcs != 0) {
    delete[]mModifyProcs;
    delete[]mCbArgs;
  }
  if (mNPredeleteProcs != 0) {
    delete[]mPredeleteProcs;
    delete[]mPredeleteCbArgs;
  }
}


/*
 This function copies verbose whatever is in front and after the gap into a
 single buffer.
 Unicode safe.
 */
char *Fl_Text_Buffer::text() const {
  char *t = (char *) malloc(mLength + 1);
  memcpy(t, mBuf, mGapStart);
  memcpy(t+mGapStart, mBuf+mGapEnd, mLength - mGapStart);
  t[mLength] = '\0';
  return t;
} 


/*
 Set the text buffer to a new string.
 Unicode safe.
 */
void Fl_Text_Buffer::text(const char *t)
{
  call_predelete_callbacks(0, length());
  
  /* Save information for redisplay, and get rid of the old buffer */
  const char *deletedText = text();
  int deletedLength = mLength;
  free((void *) mBuf);
  
  /* Start a new buffer with a gap of mPreferredGapSize at the end */
  int insertedLength = strlen(t);
  mBuf = (char *) malloc(insertedLength + mPreferredGapSize);
  mLength = insertedLength;
  mGapStart = insertedLength;
  mGapEnd = mGapStart + mPreferredGapSize;
  memcpy(mBuf, t, insertedLength);
  
  /* Zero all of the existing selections */
  update_selections(0, deletedLength, 0);
  
  /* Call the saved display routine(s) to update the screen */
  call_modify_callbacks(0, deletedLength, insertedLength, 0, deletedText);
  free((void *) deletedText);
}


/*
 Creates a range of text to a new buffer and copies verbose from around the gap.
 Unicode safe.
 */
char *Fl_Text_Buffer::text_range(int start, int end) const {
  char *s = NULL;
  
  /* Make sure start and end are ok, and allocate memory for returned string.
   If start is bad, return "", if end is bad, adjust it. */
  if (start < 0 || start > mLength)
  {
    s = (char *) malloc(1);
    s[0] = '\0';
    return s;
  }
  if (end < start) {
    int temp = start;
    start = end;
    end = temp;
  }
  if (end > mLength)
    end = mLength;
  int copiedLength = end - start;
  s = (char *) malloc(copiedLength + 1);
  
  /* Copy the text from the buffer to the returned string */
  if (end <= mGapStart) {
    memcpy(s, mBuf + start, copiedLength);
  } else if (start >= mGapStart) {
    memcpy(s, mBuf + start + (mGapEnd - mGapStart), copiedLength);
  } else {
    int part1Length = mGapStart - start;
    memcpy(s, mBuf + start, part1Length);
    memcpy(s + part1Length, mBuf + mGapEnd, copiedLength - part1Length);
  }
  s[copiedLength] = '\0';
  return s;
}

/*
 Return a UCS-4 character at the given index.
 Unicode safe. Pos must be at a character boundary.
 */
unsigned int Fl_Text_Buffer::char_at(int pos) const {
  if (pos < 0 || pos >= mLength)
    return '\0';
  const char *src = address(pos);
  return fl_utf8decode(src, 0, 0);
} 


/*
 Return the raw byte at the given index.
 This function ignores all unicode encoding.
 */
char Fl_Text_Buffer::byte_at(int pos) const {
  if (pos < 0 || pos >= mLength)
    return '\0';
  const char *src = address(pos);
  return *src;
} 


/*
 Insert some text at the given index.
 Unicode safe. Pos must be at a character boundary.
*/
void Fl_Text_Buffer::insert(int pos, const char *text)
{
  /* check if there is actually any text */
  if (!text || !*text)
    return;
  
  /* if pos is not contiguous to existing text, make it */
  if (pos > mLength)
    pos = mLength;
  if (pos < 0)
    pos = 0;
  
  /* Even if nothing is deleted, we must call these callbacks */
  call_predelete_callbacks(pos, 0);
  
  /* insert and redisplay */
  int nInserted = insert_(pos, text);
  mCursorPosHint = pos + nInserted;
  call_modify_callbacks(pos, 0, nInserted, 0, NULL);
}


/*
 Replace a range of text with new text.
 Unicode safe. Start and end must be at a character boundary.
*/
void Fl_Text_Buffer::replace(int start, int end, const char *text)
{
  // Range check...
  if (!text)
    return;
  if (start < 0)
    start = 0;
  if (end > mLength)
    end = mLength;
  
  call_predelete_callbacks(start, end - start);
  const char *deletedText = text_range(start, end);
  remove_(start, end);
  int nInserted = insert_(start, text);
  mCursorPosHint = start + nInserted;
  call_modify_callbacks(start, end - start, nInserted, 0, deletedText);
  free((void *) deletedText);
}


/*
 Remove a range of text.
 Unicode safe. Start and End must be at a character boundary.
*/
void Fl_Text_Buffer::remove(int start, int end)
{
  /* Make sure the arguments make sense */
  if (start > end) {
    int temp = start;
    start = end;
    end = temp;
  }
  if (start > mLength)
    start = mLength;
  if (start < 0)
    start = 0;
  if (end > mLength)
    end = mLength;
  if (end < 0)
    end = 0;
  
  if (start == end)
    return;
  
  call_predelete_callbacks(start, end - start);
  /* Remove and redisplay */
  const char *deletedText = text_range(start, end);
  remove_(start, end);
  mCursorPosHint = start;
  call_modify_callbacks(start, end - start, 0, 0, deletedText);
  free((void *) deletedText);
}


/*
 Copy a range of text from another text buffer.
 Unicode safe. FromDtart, fromEnd, and toPos must be at a character boundary.
 */
void Fl_Text_Buffer::copy(Fl_Text_Buffer * fromBuf, int fromStart,
			  int fromEnd, int toPos)
{
  int copiedLength = fromEnd - fromStart;
  
  /* Prepare the buffer to receive the new text.  If the new text fits in
   the current buffer, just move the gap (if necessary) to where
   the text should be inserted.  If the new text is too large, reallocate
   the buffer with a gap large enough to accomodate the new text and a
   gap of mPreferredGapSize */
  if (copiedLength > mGapEnd - mGapStart)
    reallocate_with_gap(toPos, copiedLength + mPreferredGapSize);
  else if (toPos != mGapStart)
    move_gap(toPos);
  
  /* Insert the new text (toPos now corresponds to the start of the gap) */
  if (fromEnd <= fromBuf->mGapStart) {
    memcpy(&mBuf[toPos], &fromBuf->mBuf[fromStart], copiedLength);
  } else if (fromStart >= fromBuf->mGapStart) {
    memcpy(&mBuf[toPos],
	   &fromBuf->mBuf[fromStart + (fromBuf->mGapEnd - fromBuf->mGapStart)],
	   copiedLength);
  } else {
    int part1Length = fromBuf->mGapStart - fromStart;
    memcpy(&mBuf[toPos], &fromBuf->mBuf[fromStart], part1Length);
    memcpy(&mBuf[toPos + part1Length],
	   &fromBuf->mBuf[fromBuf->mGapEnd], copiedLength - part1Length);
  }
  mGapStart += copiedLength;
  mLength += copiedLength;
  update_selections(toPos, 0, copiedLength);
}


/*
 Take the previous changes and undo them. Return the previous
 cursor position in cursorPos. Returns 1 if the undo was applied.
 Unicode safe. CursorPos will be at a character boundary.
 */ 
int Fl_Text_Buffer::undo(int *cursorPos)
{
  if (undowidget != this || !undocut && !undoinsert && !mCanUndo)
    return 0;
  
  int ilen = undocut;
  int xlen = undoinsert;
  int b = undoat - xlen;
  
  if (xlen && undoyankcut && !ilen) {
    ilen = undoyankcut;
  }
  
  if (xlen && ilen) {
    undobuffersize(ilen + 1);
    undobuffer[ilen] = 0;
    char *tmp = strdup(undobuffer);
    replace(b, undoat, tmp);
    if (cursorPos)
      *cursorPos = mCursorPosHint;
    free(tmp);
  } else if (xlen) {
    remove(b, undoat);
    if (cursorPos)
      *cursorPos = mCursorPosHint;
  } else if (ilen) {
    undobuffersize(ilen + 1);
    undobuffer[ilen] = 0;
    insert(undoat, undobuffer);
    if (cursorPos)
      *cursorPos = mCursorPosHint;
    undoyankcut = 0;
  }
  
  return 1;
}


/*
 Set a flag is undo function will work.
 Unicode safe.
 */
void Fl_Text_Buffer::canUndo(char flag)
{
  mCanUndo = flag;
  // disabeling undo also clears the last undo operation!
  if (!mCanUndo && undowidget==this) 
    undowidget = 0;
}


/*
 Change the tab width. This will cause a couple of callbacks and a complete 
 redisplay. 
 Matt: I am not entirely sure why we need to trigger callbacks because
 tabs are only a graphical hint, not changing any text at all, but I leave
 this in here for back compatibility. 
 Unicode safe.
 */
void Fl_Text_Buffer::tab_distance(int tabDist)
{
  /* First call the pre-delete callbacks with the previous tab setting 
   still active. */
  call_predelete_callbacks(0, mLength);
  
  /* Change the tab setting */
  mTabDist = tabDist;
  
  /* Force any display routines to redisplay everything (unfortunately,
   this means copying the whole buffer contents to provide "deletedText" */
  const char *deletedText = text();
  call_modify_callbacks(0, mLength, mLength, 0, deletedText);
  free((void *) deletedText);
}


/*
 Select a range of text.
 Unicode safe. Start and End must be at a character boundary.
 */
void Fl_Text_Buffer::select(int start, int end)
{
  Fl_Text_Selection oldSelection = mPrimary;
  
  mPrimary.set(start, end);
  redisplay_selection(&oldSelection, &mPrimary);
}


/*
 Clear the primary selection.
 Unicode safe.
 */
void Fl_Text_Buffer::unselect()
{
  Fl_Text_Selection oldSelection = mPrimary;
  
  mPrimary.mSelected = 0;
  redisplay_selection(&oldSelection, &mPrimary);
}

  
/*
 Return the primary selection range.
 Unicode safe.
 */
int Fl_Text_Buffer::selection_position(int *start, int *end)
{
  return mPrimary.position(start, end);
}


/*
 Return a copy of the selected text.
 Unicode safe.
 */
char *Fl_Text_Buffer::selection_text()
{
  return selection_text_(&mPrimary);
}


/*
 Remove the selected text.
 Unicode safe.
 */
void Fl_Text_Buffer::remove_selection()
{
  remove_selection_(&mPrimary);
}


/*
 Replace the selected text.
 Unicode safe.
 */
void Fl_Text_Buffer::replace_selection(const char *text)
{
  replace_selection_(&mPrimary, text);
}


/*
 Select text.
 Unicode safe. Start and End must be at a character boundary.
 */
void Fl_Text_Buffer::secondary_select(int start, int end)
{
  Fl_Text_Selection oldSelection = mSecondary;
  
  mSecondary.set(start, end);
  redisplay_selection(&oldSelection, &mSecondary);
}


/*
 Deselect text.
 Unicode safe.
 */
void Fl_Text_Buffer::secondary_unselect()
{
  Fl_Text_Selection oldSelection = mSecondary;
  
  mSecondary.mSelected = 0;
  redisplay_selection(&oldSelection, &mSecondary);
}

  
/*
 Return the selected range.
 Unicode safe.
 */
int Fl_Text_Buffer::secondary_selection_position(int *start, int *end)
{
  return mSecondary.position(start, end);
}


/*
 Return a copy of the text in this selection.
 Unicode safe.
 */
char *Fl_Text_Buffer::secondary_selection_text()
{
  return selection_text_(&mSecondary);
}


/*
 Remove the selected text.
 Unicode safe.
 */
void Fl_Text_Buffer::remove_secondary_selection()
{
  remove_selection_(&mSecondary);
}


/*
 Replace selected text.
 Unicode safe.
 */
void Fl_Text_Buffer::replace_secondary_selection(const char *text)
{
  replace_selection_(&mSecondary, text);
}


/*
 Highlight a range of text.
 Unicode safe. Start and End must be at a character boundary.
 */
void Fl_Text_Buffer::highlight(int start, int end)
{
  Fl_Text_Selection oldSelection = mHighlight;
  
  mHighlight.set(start, end);
  redisplay_selection(&oldSelection, &mHighlight);
}


/*
 Remove text highlighting.
 Unicode safe.
 */
void Fl_Text_Buffer::unhighlight()
{
  Fl_Text_Selection oldSelection = mHighlight;
  
  mHighlight.mSelected = 0;
  redisplay_selection(&oldSelection, &mHighlight);
}

  
/*
 Return position of highlight.
 Unicode safe.
 */
int Fl_Text_Buffer::highlight_position(int *start, int *end)
{
  return mHighlight.position(start, end);
}


/*
 Return a copy of highlighted text.
 Unicode safe.
 */
char *Fl_Text_Buffer::highlight_text()
{
  return selection_text_(&mHighlight);
}


/*
 Add a callback that is called whenever text is modified.
 Unicode safe.
 */
void Fl_Text_Buffer::add_modify_callback(Fl_Text_Modify_Cb bufModifiedCB,
					 void *cbArg)
{
  Fl_Text_Modify_Cb *newModifyProcs =
  new Fl_Text_Modify_Cb[mNModifyProcs + 1];
  void **newCBArgs = new void *[mNModifyProcs + 1];
  for (int i = 0; i < mNModifyProcs; i++) {
    newModifyProcs[i + 1] = mModifyProcs[i];
    newCBArgs[i + 1] = mCbArgs[i];
  }
  if (mNModifyProcs != 0) {
    delete[]mModifyProcs;
    delete[]mCbArgs;
  }
  newModifyProcs[0] = bufModifiedCB;
  newCBArgs[0] = cbArg;
  mNModifyProcs++;
  mModifyProcs = newModifyProcs;
  mCbArgs = newCBArgs;
}


/*
 Remove a callback.
 Unicode safe.
 */
void Fl_Text_Buffer::remove_modify_callback(Fl_Text_Modify_Cb bufModifiedCB, 
                                            void *cbArg)
{
  int i, toRemove = -1;
  
  /* find the matching callback to remove */
  for (i = 0; i < mNModifyProcs; i++) {
    if (mModifyProcs[i] == bufModifiedCB && mCbArgs[i] == cbArg) {
      toRemove = i;
      break;
    }
  }
  if (toRemove == -1) {
    Fl::error
    ("Fl_Text_Buffer::remove_modify_callback(): Can't find modify CB to remove");
    return;
  }
  
  /* Allocate new lists for remaining callback procs and args (if
   any are left) */
  mNModifyProcs--;
  if (mNModifyProcs == 0) {
    mNModifyProcs = 0;
    delete[]mModifyProcs;
    mModifyProcs = NULL;
    delete[]mCbArgs;
    mCbArgs = NULL;
    return;
  }
  Fl_Text_Modify_Cb *newModifyProcs = new Fl_Text_Modify_Cb[mNModifyProcs];
  void **newCBArgs = new void *[mNModifyProcs];
  
  /* copy out the remaining members and free the old lists */
  for (i = 0; i < toRemove; i++) {
    newModifyProcs[i] = mModifyProcs[i];
    newCBArgs[i] = mCbArgs[i];
  }
  for (; i < mNModifyProcs; i++) {
    newModifyProcs[i] = mModifyProcs[i + 1];
    newCBArgs[i] = mCbArgs[i + 1];
  }
  delete[]mModifyProcs;
  delete[]mCbArgs;
  mModifyProcs = newModifyProcs;
  mCbArgs = newCBArgs;
}


/*
 Add a callback that is called before deleting text.
 Unicode safe.
 */
void Fl_Text_Buffer::add_predelete_callback(Fl_Text_Predelete_Cb bufPreDeleteCB, 
                                            void *cbArg)
{
  Fl_Text_Predelete_Cb *newPreDeleteProcs =
  new Fl_Text_Predelete_Cb[mNPredeleteProcs + 1];
  void **newCBArgs = new void *[mNPredeleteProcs + 1];
  for (int i = 0; i < mNPredeleteProcs; i++) {
    newPreDeleteProcs[i + 1] = mPredeleteProcs[i];
    newCBArgs[i + 1] = mPredeleteCbArgs[i];
  }
  if (!mNPredeleteProcs != 0) {
    delete[]mPredeleteProcs;
    delete[]mPredeleteCbArgs;
  }
  newPreDeleteProcs[0] = bufPreDeleteCB;
  newCBArgs[0] = cbArg;
  mNPredeleteProcs++;
  mPredeleteProcs = newPreDeleteProcs;
  mPredeleteCbArgs = newCBArgs;
}


/*
 Remove a callback.
 Unicode safe.
 */
void Fl_Text_Buffer::remove_predelete_callback(Fl_Text_Predelete_Cb bufPreDeleteCB, void *cbArg)
{
  int i, toRemove = -1;
  /* find the matching callback to remove */
  for (i = 0; i < mNPredeleteProcs; i++) {
    if (mPredeleteProcs[i] == bufPreDeleteCB &&
	mPredeleteCbArgs[i] == cbArg) {
      toRemove = i;
      break;
    }
  }
  if (toRemove == -1) {
    Fl::error
    ("Fl_Text_Buffer::remove_predelete_callback(): Can't find pre-delete CB to remove");
    return;
  }
  
  /* Allocate new lists for remaining callback procs and args (if
   any are left) */
  mNPredeleteProcs--;
  if (mNPredeleteProcs == 0) {
    mNPredeleteProcs = 0;
    delete[]mPredeleteProcs;
    mPredeleteProcs = NULL;
    delete[]mPredeleteCbArgs;
    mPredeleteCbArgs = NULL;
    return;
  }
  Fl_Text_Predelete_Cb *newPreDeleteProcs =
  new Fl_Text_Predelete_Cb[mNPredeleteProcs];
  void **newCBArgs = new void *[mNPredeleteProcs];
  
  /* copy out the remaining members and free the old lists */
  for (i = 0; i < toRemove; i++) {
    newPreDeleteProcs[i] = mPredeleteProcs[i];
    newCBArgs[i] = mPredeleteCbArgs[i];
  }
  for (; i < mNPredeleteProcs; i++) {
    newPreDeleteProcs[i] = mPredeleteProcs[i + 1];
    newCBArgs[i] = mPredeleteCbArgs[i + 1];
  }
  delete[]mPredeleteProcs;
  delete[]mPredeleteCbArgs;
  mPredeleteProcs = newPreDeleteProcs;
  mPredeleteCbArgs = newCBArgs;
}


/*
 Return a copy of the line that contains a given index.
 Unicode safe. Pos must be at a character boundary.
 */
char *Fl_Text_Buffer::line_text(int pos) const {
  return text_range(line_start(pos), line_end(pos));
} 


/*
 Find the beginning of the line.
 NOT UNICODE SAFE.
 */
int Fl_Text_Buffer::line_start(int pos) const 
{
  // FIXME: this currently works for unicode, but will be very inefficent when findchar_backward is fixed.
  if (!findchar_backward(pos, '\n', &pos))
    return 0;
  return pos + 1;
} 


/*
 Find the end of the line.
 NOT UNICODE SAFE.
 */
int Fl_Text_Buffer::line_end(int pos) const {
  // FIXME: this currently works for unicode, but will be very inefficent when findchar_forward is fixed.
  if (!findchar_forward(pos, '\n', &pos))
    pos = mLength;
  return pos;
} 


/*
 Find the beginning of a word.
 NOT UNICODE SAFE.
 */
int Fl_Text_Buffer::word_start(int pos) const {
  // FIXME: character is ucs-4
  while (pos && (isalnum(char_at(pos)) || char_at(pos) == '_')) {
    pos--;
  } 
  // FIXME: character is ucs-4
  if (!(isalnum(char_at(pos)) || char_at(pos) == '_'))
    pos++;
  return pos;
}


/*
 Find the end of a word.
 NOT UNICODE SAFE.
 */
int Fl_Text_Buffer::word_end(int pos) const {
  // FIXME: character is ucs-4
  while (pos < length() && (isalnum(char_at(pos)) || char_at(pos) == '_'))
  {
    pos++;
  } return pos;
}


/*
 Matt: I am not sure why we need this function. Does it still make sense in
 the world of proportional characters?
 */
int Fl_Text_Buffer::count_displayed_characters(int lineStartPos,
					       int targetPos) const
{
  // TODO: is this function still needed? If it is, put this functionality in handle_vline?
  int charCount = 0;
  
  int pos = lineStartPos;
  while (pos < targetPos) {
    int len = fl_utf8len(*address(pos));
    charCount += 1;
    pos += len;
  }
  return charCount;
} 


/*
 Matt: I am not sure why we need this function. Does it still make sense in
 the world of proportional characters?
 */
// All values are number of bytes. 
// - unicode ok?
int Fl_Text_Buffer::skip_displayed_characters(int lineStartPos, int nChars)
{
  // FIXME: is this function still needed?
  int pos = lineStartPos;
  
  for (int charCount = 0; charCount < nChars && pos < mLength;) {
    const char *src = address(pos);
    char c = *src;
    if (c == '\n')
      return pos;
    charCount++;
    pos += fl_utf8len(c);
  }
  return pos;
}


/*
 Count the number of newline characters between start and end.
 Unicode safe. StartPos and endPos must be at a character boundary.
 */
int Fl_Text_Buffer::count_lines(int startPos, int endPos) const {
  int gapLen = mGapEnd - mGapStart;
  int lineCount = 0;
  
  int pos = startPos;
  while (pos < mGapStart)
  {
    if (pos == endPos)
      return lineCount;
    if (mBuf[pos++] == '\n')
      lineCount++;
  } 
  while (pos < mLength) {
    if (pos == endPos)
      return lineCount;
    if (mBuf[pos++ + gapLen] == '\n')
      lineCount++;
  }
  return lineCount;
}


/*
 Skip to the first character, n lines ahead.
 Unicode safe. StartPos must be at a character boundary.
 */
int Fl_Text_Buffer::skip_lines(int startPos, int nLines)
{
  if (nLines == 0)
    return startPos;
  
  int gapLen = mGapEnd - mGapStart;
  int pos = startPos;
  int lineCount = 0;
  while (pos < mGapStart) {
    if (mBuf[pos++] == '\n') {
      lineCount++;
      if (lineCount == nLines)
	return pos;
    }
  }
  while (pos < mLength) {
    if (mBuf[pos++ + gapLen] == '\n') {
      lineCount++;
      if (lineCount >= nLines)
	return pos;
    }
  }
  return pos;
}


/*
 Skip to the first character, n lines back.
 Unicode safe. StartPos must be at a character boundary.
 */
int Fl_Text_Buffer::rewind_lines(int startPos, int nLines)
{
  int pos = startPos - 1;
  if (pos <= 0)
    return 0;
  
  int gapLen = mGapEnd - mGapStart;
  int lineCount = -1;
  while (pos >= mGapStart) {
    if (mBuf[pos + gapLen] == '\n') {
      if (++lineCount >= nLines)
	return pos + 1;
    }
    pos--;
  }
  while (pos >= 0) {
    if (mBuf[pos] == '\n') {
      if (++lineCount >= nLines)
	return pos + 1;
    }
    pos--;
  }
  return 0;
}


/*
 Find a matching string in the buffer.
 NOT TESTED FOR UNICODE.
 */
int Fl_Text_Buffer::search_forward(int startPos, const char *searchString,
				   int *foundPos, int matchCase) const 
{
  // FIXME: Unicode?
  if (!searchString)
    return 0;
  int bp;
  const char *sp;
  while (startPos < length()) {
    bp = startPos;
    sp = searchString;
    do {
      if (!*sp) {
        *foundPos = startPos;
        return 1;
      }
      // FIXME: character is ucs-4
    } while ((matchCase ? char_at(bp++) == (unsigned int)*sp++ :
              toupper(char_at(bp++)) == toupper(*sp++))
             && bp < length());
    startPos++;
  }
  return 0;
}


/*
 Find a matching string in the buffer.
 NOT TESTED FOR UNICODE.
 */
int Fl_Text_Buffer::search_backward(int startPos, const char *searchString,
				    int *foundPos, int matchCase) const {
  // FIXME: Unicode?
  if (!searchString)
    return 0;
  int bp;
  const char *sp;
  while (startPos > 0)
  {
    bp = startPos - 1;
    sp = searchString + strlen(searchString) - 1;
    do {
      if (sp < searchString) {
        *foundPos = bp + 1;
        return 1;
      }
      // FIXME: character is ucs-4
    } while ((matchCase ? char_at(bp--) == (unsigned int)*sp-- :
              toupper(char_at(bp--)) == toupper(*sp--))
             && bp >= 0);
    startPos--;
  }
  return 0;
}


/*
 Find a matching string in the buffer.
 NOT TESTED FOR UNICODE.
 */
int Fl_Text_Buffer::findchars_forward(int startPos, const char *searchChars,
				      int *foundPos) const {
  // FIXME: unicode?
  int gapLen = mGapEnd - mGapStart;
  const char *c;
  
  int pos = startPos;
  while (pos < mGapStart)
  {
    for (c = searchChars; *c != '\0'; c++) {
      if (mBuf[pos] == *c) {
        *foundPos = pos;
        return 1;
      }
    } pos++;
  }
  while (pos < mLength) {
    for (c = searchChars; *c != '\0'; c++) {
      if (mBuf[pos + gapLen] == *c) {
	*foundPos = pos;
	return 1;
      }
    }
    pos++;
  }
  *foundPos = mLength;
  return 0;
}


/*
 Find a matching string in the buffer.
 NOT TESTED FOR UNICODE.
 */
int Fl_Text_Buffer::findchars_backward(int startPos, const char *searchChars,
				       int *foundPos) const {
  // FIXME: Unicode
  int gapLen = mGapEnd - mGapStart;
  const char *c;
  
  if (startPos == 0)
  {
    *foundPos = 0;
    return 0;
  }
  int pos = startPos == 0 ? 0 : startPos - 1;
  while (pos >= mGapStart) {
    for (c = searchChars; *c != '\0'; c++) {
      if (mBuf[pos + gapLen] == *c) {
	*foundPos = pos;
	return 1;
      }
    }
    pos--;
  }
  while (pos >= 0) {
    for (c = searchChars; *c != '\0'; c++) {
      if (mBuf[pos] == *c) {
	*foundPos = pos;
	return 1;
      }
    }
    pos--;
  }
  *foundPos = 0;
  return 0;
}


/*
 Insert a string into the buffer.
 Unicode safe. Pos must be at a character boundary. Text must be a correct utf8 string.
 */
int Fl_Text_Buffer::insert_(int pos, const char *text)
{
  if (!text || !*text)
    return 0;
  
  int insertedLength = strlen(text);
  
  /* Prepare the buffer to receive the new text.  If the new text fits in
   the current buffer, just move the gap (if necessary) to where
   the text should be inserted.  If the new text is too large, reallocate
   the buffer with a gap large enough to accomodate the new text and a
   gap of mPreferredGapSize */
  if (insertedLength > mGapEnd - mGapStart)
    reallocate_with_gap(pos, insertedLength + mPreferredGapSize);
  else if (pos != mGapStart)
    move_gap(pos);
  
  /* Insert the new text (pos now corresponds to the start of the gap) */
  memcpy(&mBuf[pos], text, insertedLength);
  mGapStart += insertedLength;
  mLength += insertedLength;
  update_selections(pos, 0, insertedLength);
  
  if (mCanUndo) {
    if (undowidget == this && undoat == pos && undoinsert) {
      undoinsert += insertedLength;
    } else {
      undoinsert = insertedLength;
      undoyankcut = (undoat == pos) ? undocut : 0;
    }
    undoat = pos + insertedLength;
    undocut = 0;
    undowidget = this;
  }
  
  return insertedLength;
}


/*
 Remove a string from the buffer.
 Unicode safe. Start and end must be at a character boundary.
 */
void Fl_Text_Buffer::remove_(int start, int end)
{
  /* if the gap is not contiguous to the area to remove, move it there */
  
  if (mCanUndo) {
    if (undowidget == this && undoat == end && undocut) {
      undobuffersize(undocut + end - start + 1);
      memmove(undobuffer + end - start, undobuffer, undocut);
      undocut += end - start;
    } else {
      undocut = end - start;
      undobuffersize(undocut);
    }
    undoat = start;
    undoinsert = 0;
    undoyankcut = 0;
    undowidget = this;
  }
  
  if (start > mGapStart) {
    if (mCanUndo)
      memcpy(undobuffer, mBuf + (mGapEnd - mGapStart) + start,
	     end - start);
    move_gap(start);
  } else if (end < mGapStart) {
    if (mCanUndo)
      memcpy(undobuffer, mBuf + start, end - start);
    move_gap(end);
  } else {
    int prelen = mGapStart - start;
    if (mCanUndo) {
      memcpy(undobuffer, mBuf + start, prelen);
      memcpy(undobuffer + prelen, mBuf + mGapEnd, end - start - prelen);
    }
  }
  
  /* expand the gap to encompass the deleted characters */
  mGapEnd += end - mGapStart;
  mGapStart -= mGapStart - start;
  
  /* update the length */
  mLength -= end - start;
  
  /* fix up any selections which might be affected by the change */
  update_selections(start, end - start, 0);
}

  
/*
 simple setter.
 Unicode safe. Start and end must be at a character boundary.
 */
void Fl_Text_Selection::set(int startpos, int endpos)
{
  mSelected = startpos != endpos;
  mStart = min(startpos, endpos);
  mEnd = max(startpos, endpos);
}


/*
 simple getter.
 Unicode safe. Start and end will be at a character boundary.
 */
int Fl_Text_Selection::position(int *startpos, int *endpos) const {
  if (!mSelected)
    return 0;
  *startpos = mStart;
  *endpos = mEnd;
  
  return 1;
} 


/*
 Return if a position is inside the eselected area.
 Unicode safe. Pos must be at a character boundary.
 */
int Fl_Text_Selection::includes(int pos) const {
  return (selected() && pos >= start() && pos < end() );
}


/*
 Return a duplicate of the selected text, or an empty string.
 Unicode safe.
 */
char *Fl_Text_Buffer::selection_text_(Fl_Text_Selection * sel) const {
  int start, end;
  
  /* If there's no selection, return an allocated empty string */
  if (!sel->position(&start, &end))
  {
    char *s = (char *) malloc(1);
    *s = '\0';
    return s;
  }
  
  /* Return the selected range */
    return text_range(start, end);
}


/*
 Remove the selected text.
 Unicode safe.
 */
void Fl_Text_Buffer::remove_selection_(Fl_Text_Selection * sel)
{
  int start, end;
  
  if (!sel->position(&start, &end))
    return;
    remove(start, end);
    //undoyankcut = undocut;
  }


/*
 Replace selection with text.
 Unicode safe.
 */
void Fl_Text_Buffer::replace_selection_(Fl_Text_Selection * sel,
					const char *text)
{
  Fl_Text_Selection oldSelection = *sel;
  
  /* If there's no selection, return */
  int start, end;
  if (!sel->position(&start, &end))
    return;
  
  /* Do the appropriate type of replace */
    replace(start, end, text);
  
  /* Unselect (happens automatically in BufReplace, but BufReplaceRect
   can't detect when the contents of a selection goes away) */
  sel->mSelected = 0;
  redisplay_selection(&oldSelection, sel);
}

  
/*
 Call all callbacks.
 Unicode safe.
 */
void Fl_Text_Buffer::call_modify_callbacks(int pos, int nDeleted,
					   int nInserted, int nRestyled,
					   const char *deletedText) const {
  for (int i = 0; i < mNModifyProcs; i++)
    (*mModifyProcs[i]) (pos, nInserted, nDeleted, nRestyled,
			deletedText, mCbArgs[i]);
} 


/*
 Call all callbacks.
 Unicode safe.
 */
void Fl_Text_Buffer::call_predelete_callbacks(int pos, int nDeleted) const {
  for (int i = 0; i < mNPredeleteProcs; i++)
    (*mPredeleteProcs[i]) (pos, nDeleted, mPredeleteCbArgs[i]);
} 


/*
 Redisplay a new selected area.
 Unicode safe.
 */
void Fl_Text_Buffer::redisplay_selection(Fl_Text_Selection *
					   oldSelection,
					   Fl_Text_Selection *
					   newSelection) const
{
  int oldStart, oldEnd, newStart, newEnd, ch1Start, ch1End, ch2Start,
  ch2End;
  
  /* If either selection is rectangular, add an additional character to
   the end of the selection to request the redraw routines to wipe out
   the parts of the selection beyond the end of the line */
  oldStart = oldSelection->mStart;
  newStart = newSelection->mStart;
  oldEnd = oldSelection->mEnd;
  newEnd = newSelection->mEnd;
  
  /* If the old or new selection is unselected, just redisplay the
   single area that is (was) selected and return */
  if (!oldSelection->mSelected && !newSelection->mSelected)
    return;
  if (!oldSelection->mSelected)
  {
    call_modify_callbacks(newStart, 0, 0, newEnd - newStart, NULL);
    return;
  }
  if (!newSelection->mSelected) {
    call_modify_callbacks(oldStart, 0, 0, oldEnd - oldStart, NULL);
    return;
  }
  
  /* If the selections are non-contiguous, do two separate updates
   and return */
  if (oldEnd < newStart || newEnd < oldStart) {
    call_modify_callbacks(oldStart, 0, 0, oldEnd - oldStart, NULL);
    call_modify_callbacks(newStart, 0, 0, newEnd - newStart, NULL);
    return;
  }
  
  /* Otherwise, separate into 3 separate regions: ch1, and ch2 (the two
   changed areas), and the unchanged area of their intersection,
   and update only the changed area(s) */
  ch1Start = min(oldStart, newStart);
  ch2End = max(oldEnd, newEnd);
  ch1End = max(oldStart, newStart);
  ch2Start = min(oldEnd, newEnd);
  if (ch1Start != ch1End)
    call_modify_callbacks(ch1Start, 0, 0, ch1End - ch1Start, NULL);
  if (ch2Start != ch2End)
    call_modify_callbacks(ch2Start, 0, 0, ch2End - ch2Start, NULL);
}


/*
 Move the gap around without changing buffer content.
 Unicode safe. Pos must be at a character boundary.
 */
void Fl_Text_Buffer::move_gap(int pos)
{
  int gapLen = mGapEnd - mGapStart;
  
  if (pos > mGapStart)
    memmove(&mBuf[mGapStart], &mBuf[mGapEnd], pos - mGapStart);
  else
    memmove(&mBuf[pos + gapLen], &mBuf[pos], mGapStart - pos);
  mGapEnd += pos - mGapStart;
  mGapStart += pos - mGapStart;
}


/*
 Create a larger gap.
 Unicode safe. Start must be at a character boundary.
 */
void Fl_Text_Buffer::reallocate_with_gap(int newGapStart, int newGapLen)
{
  char *newBuf = (char *) malloc(mLength + newGapLen);
  int newGapEnd = newGapStart + newGapLen;
  
  if (newGapStart <= mGapStart) {
    memcpy(newBuf, mBuf, newGapStart);
    memcpy(&newBuf[newGapEnd], &mBuf[newGapStart],
	   mGapStart - newGapStart);
    memcpy(&newBuf[newGapEnd + mGapStart - newGapStart],
	   &mBuf[mGapEnd], mLength - mGapStart);
  } else {			/* newGapStart > mGapStart */
    memcpy(newBuf, mBuf, mGapStart);
    memcpy(&newBuf[mGapStart], &mBuf[mGapEnd], newGapStart - mGapStart);
    memcpy(&newBuf[newGapEnd],
	   &mBuf[mGapEnd + newGapStart - mGapStart],
	   mLength - newGapStart);
  }
  free((void *) mBuf);
  mBuf = newBuf;
  mGapStart = newGapStart;
  mGapEnd = newGapEnd;
  }


/*
 Update selection range if characers were inserted.
 Unicode safe. Pos must be at a character boundary.
 */
void Fl_Text_Buffer::update_selections(int pos, int nDeleted,
				       int nInserted)
{
  mPrimary.update(pos, nDeleted, nInserted);
  mSecondary.update(pos, nDeleted, nInserted);
  mHighlight.update(pos, nDeleted, nInserted);
}


// unicode safe, assuming the arguments are on character boundaries
void Fl_Text_Selection::update(int pos, int nDeleted, int nInserted)
{
  // FIXME: check if this is safe when seletion crosses selction boundaries
  if (!mSelected || pos > mEnd)
    return;
  if (pos + nDeleted <= mStart) {
    mStart += nInserted - nDeleted;
    mEnd += nInserted - nDeleted;
  } else if (pos <= mStart && pos + nDeleted >= mEnd) {
    mStart = pos;
    mEnd = pos;
    mSelected = 0;
  } else if (pos <= mStart && pos + nDeleted < mEnd) {
    mStart = pos;
    mEnd = nInserted + mEnd - nDeleted;
  } else if (pos < mEnd) {
    mEnd += nInserted - nDeleted;
    if (mEnd <= mStart)
      mSelected = 0;
  }
}


/*
 Find a UCS-4 character.
 Unicode safe. StartPos must be at a charcter boundary, searchChar is UCS-4 encoded.
 */
int Fl_Text_Buffer::findchar_forward(int startPos, unsigned searchChar,
				     int *foundPos) const 
  {
  if (startPos >= mLength)
  {
    *foundPos = mLength;
    return 0;
  }
  
  if (startPos<0)
    startPos = 0;
  
  // TODO: for performance reasons, we can re-insert the ASCII search here which is about three times as fast if searchChar is <128
  
  for ( ; startPos<mLength; startPos = next_char(startPos)) {
    if (searchChar == char_at(startPos)) {
      *foundPos = startPos;
      return 1;
    }
  }
  
  *foundPos = mLength;
  return 0;
}

  
/*
 Find a UCS-4 character.
 Unicode safe. StartPos must be at a charcter boundary, searchChar is UCS-4 encoded.
 */
int Fl_Text_Buffer::findchar_backward(int startPos, unsigned searchChar,
				      int *foundPos) const {
  if (startPos <= 0) {
    *foundPos = 0;
    return 0;
  }
  
  if (startPos > mLength)
    startPos = mLength;
  
  // TODO: for performance reasons, we can re-insert the ASCII search here which is about three times as fast if searchChar is <128
  
  for (startPos = prev_char(startPos); startPos>=0; startPos = prev_char(startPos)) {
    if (searchChar == char_at(startPos)) {
      *foundPos = startPos;
      return 1;
    }
  }
  
  *foundPos = 0;
  return 0;
}

  
/*
 Insert text from a file.
 Unicode safe. Inout must be correct utf8!
 */
int Fl_Text_Buffer::insertfile(const char *file, int pos, int buflen)
{
  FILE *fp;
  if (!(fp = fl_fopen(file, "r")))
    return 1;
  char *buffer = new char[buflen];
  for (int r; (r = fread(buffer, 1, buflen - 1, fp)) > 0; pos += r) {
    buffer[r] = (char) 0;
    insert(pos, buffer);
  }
  
  int e = ferror(fp) ? 2 : 0;
  fclose(fp);
  delete[]buffer;
  return e;
}


/*
 Write text to file,
 Unicode safe.
 */
int Fl_Text_Buffer::outputfile(const char *file, int start, int end,
			       int buflen)
{
  FILE *fp;
  if (!(fp = fl_fopen(file, "wb")))
    return 1;
  for (int n; (n = min(end - start, buflen)); start += n) {
    const char *p = text_range(start, start + n);
    int r = fwrite(p, 1, n, fp);
    free((void *) p);
    if (r != n)
      break;
  }
  
  int e = ferror(fp) ? 2 : 0;
  fclose(fp);
  return e;
}


/*
 Return the previous character position.
 Uncode safe.
 */
int Fl_Text_Buffer::prev_char_clipped(int pos) const
{
  if (pos<=0)
    return 0;

  char c;
  do {
    pos--;
    if (pos==0)
      return 0;
    c = byte_at(pos);
  } while ( (c&0xc0) == 0x80);
  
  return pos;
}


/*
 Return the previous character poosition.
 Returns -1 if the beginning of the buffer is reached.
 */
int Fl_Text_Buffer::prev_char(int pos) const
{
  if (pos==0) return -1;
  return prev_char_clipped(pos);
}


/*
 Return the next character position.
 Returns length() if the end of the buffer is reached.
 */
int Fl_Text_Buffer::next_char(int pos) const
{
  int n = fl_utf8len(byte_at(pos));
  pos += n;
  if (pos>=mLength)
    return mLength;
  return pos;
}


/*
 Return the next character poosition.
 If the end of the buffer is reached, it returns the current position.
 */
int Fl_Text_Buffer::next_char_clipped(int pos) const
{
  int n = next_char(pos);
  if (pos==mLength) return pos;
  return n;
}


//
// End of "$Id$".
//