blender-archive/source/blender/blenkernel/intern/text.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */

/** \file blender/blenkernel/intern/text.c
 *  \ingroup bke
 */

#include <stdlib.h> /* abort */
#include <string.h> /* strstr */
#include <sys/types.h>
#include <sys/stat.h>
#include <wchar.h>
#include <wctype.h>

#include "MEM_guardedalloc.h"

#include "BLI_utildefines.h"
#include "BLI_path_util.h"
#include "BLI_string.h"
#include "BLI_string_cursor_utf8.h"
#include "BLI_string_utf8.h"
#include "BLI_listbase.h"
#include "BLI_fileops.h"

#include "DNA_constraint_types.h"
#include "DNA_scene_types.h"
#include "DNA_screen_types.h"
#include "DNA_space_types.h"
#include "DNA_text_types.h"
#include "DNA_userdef_types.h"
#include "DNA_object_types.h"
#include "DNA_node_types.h"
#include "DNA_material_types.h"

#include "BKE_library.h"
#include "BKE_main.h"
#include "BKE_text.h"
#include "BKE_node.h"


#ifdef WITH_PYTHON
#include "BPY_extern.h"
#endif

/*
 * How Texts should work
 * --
 * A text should relate to a file as follows -
 * (Text *)->name should be the place where the
 *     file will or has been saved.
 *
 * (Text *)->flags has the following bits
 *     TXT_ISDIRTY - should always be set if the file in mem. differs from
 *                     the file on disk, or if there is no file on disk.
 *     TXT_ISMEM - should always be set if the Text has not been mapped to
 *                     a file, in which case (Text *)->name may be NULL or garbage.
 *     TXT_ISEXT - should always be set if the Text is not to be written into
 *                     the .blend
 *     TXT_ISSCRIPT - should be set if the user has designated the text
 *                     as a script. (NEW: this was unused, but now it is needed by
 *                     space handler script links (see header_view3d.c, for example)
 *
 * ->>> see also: /makesdna/DNA_text_types.h
 *
 * Display
 * --
 * The st->top determines at what line the top of the text is displayed.
 * If the user moves the cursor the st containing that cursor should
 * be popped ... other st's retain their own top location.
 *
 * Undo
 * --
 * Undo/Redo works by storing
 * events in a queue, and a pointer
 * to the current position in the
 * queue...
 *
 * Events are stored using an
 * arbitrary op-code system
 * to keep track of
 * a) the two cursors (normal and selected)
 * b) input (visible and control (ie backspace))
 *
 * input data is stored as its
 * ASCII value, the opcodes are
 * then selected to not conflict.
 *
 * opcodes with data in between are
 * written at the beginning and end
 * of the data to allow undo and redo
 * to simply check the code at the current
 * undo position
 */


/* Undo opcodes */

enum {
	/* Complex editing */
	/* 1 - opcode is followed by 1 byte for ascii character and opcode (repeat)) */
	/* 2 - opcode is followed by 2 bytes for utf-8 character and opcode (repeat)) */
	/* 3 - opcode is followed by 3 bytes for utf-8 character and opcode (repeat)) */
	/* 4 - opcode is followed by 4 bytes for unicode character and opcode (repeat)) */
	UNDO_INSERT_1   = 013,
	UNDO_INSERT_2   = 014,
	UNDO_INSERT_3   = 015,
	UNDO_INSERT_4   = 016,

	UNDO_BS_1       = 017,
	UNDO_BS_2       = 020,
	UNDO_BS_3       = 021,
	UNDO_BS_4       = 022,

	UNDO_DEL_1      = 023,
	UNDO_DEL_2      = 024,
	UNDO_DEL_3      = 025,
	UNDO_DEL_4      = 026,

	/* Text block (opcode is followed
	 * by 4 character length ID + the text
	 * block itself + the 4 character length
	 * ID (repeat) and opcode (repeat)) */
	UNDO_DBLOCK     = 027, /* Delete block */
	UNDO_IBLOCK     = 030, /* Insert block */

	/* Misc */
	UNDO_INDENT     = 032,
	UNDO_UNINDENT   = 033,
	UNDO_COMMENT    = 034,
	UNDO_UNCOMMENT  = 035,

	UNDO_MOVE_LINES_UP      = 036,
	UNDO_MOVE_LINES_DOWN    = 037,

	UNDO_DUPLICATE  = 040,
};

/***/

static void txt_pop_first(Text *text);
static void txt_pop_last(Text *text);
static void txt_undo_add_blockop(Text *text, TextUndoBuf *utxt, int op, const char *buf);
static void txt_delete_line(Text *text, TextLine *line);
static void txt_delete_sel(Text *text, TextUndoBuf *utxt);
static void txt_make_dirty(Text *text);

/***/

/**
 * Set to true when undoing (so we don't generate undo steps while undoing).
 *
 * Also use to disable undo entirely.
 */
static bool undoing;

/**
 * \note caller must handle `undo_buf` and `compiled` members.
 */
void BKE_text_free_lines(Text *text)
{
	for (TextLine *tmp = text->lines.first, *tmp_next; tmp; tmp = tmp_next) {
		tmp_next = tmp->next;
		MEM_freeN(tmp->line);
		if (tmp->format) {
			MEM_freeN(tmp->format);
		}
		MEM_freeN(tmp);
	}

	BLI_listbase_clear(&text->lines);

	text->curl = text->sell = NULL;
}

/** Free (or release) any data used by this text (does not free the text itself). */
void BKE_text_free(Text *text)
{
	/* No animdata here. */

	BKE_text_free_lines(text);

	MEM_SAFE_FREE(text->name);
#ifdef WITH_PYTHON
	BPY_text_free_code(text);
#endif
}

void BKE_text_init(Text *ta)
{
	TextLine *tmp;

	BLI_assert(MEMCMP_STRUCT_OFS_IS_ZERO(ta, id));

	ta->name = NULL;

	ta->nlines = 1;
	ta->flags = TXT_ISDIRTY | TXT_ISMEM;
	if ((U.flag & USER_TXT_TABSTOSPACES_DISABLE) == 0)
		ta->flags |= TXT_TABSTOSPACES;

	BLI_listbase_clear(&ta->lines);

	tmp = (TextLine *) MEM_mallocN(sizeof(TextLine), "textline");
	tmp->line = (char *) MEM_mallocN(1, "textline_string");
	tmp->format = NULL;

	tmp->line[0] = 0;
	tmp->len = 0;

	tmp->next = NULL;
	tmp->prev = NULL;

	BLI_addhead(&ta->lines, tmp);

	ta->curl = ta->lines.first;
	ta->curc = 0;
	ta->sell = ta->lines.first;
	ta->selc = 0;
}

Text *BKE_text_add(Main *bmain, const char *name)
{
	Text *ta;

	ta = BKE_libblock_alloc(bmain, ID_TXT, name, 0);

	BKE_text_init(ta);

	return ta;
}

/* this function replaces extended ascii characters */
/* to a valid utf-8 sequences */
int txt_extended_ascii_as_utf8(char **str)
{
	ptrdiff_t bad_char, i = 0;
	const ptrdiff_t length = (ptrdiff_t)strlen(*str);
	int added = 0;

	while ((*str)[i]) {
		if ((bad_char = BLI_utf8_invalid_byte(*str + i, length - i)) == -1)
			break;

		added++;
		i += bad_char + 1;
	}

	if (added != 0) {
		char *newstr = MEM_mallocN(length + added + 1, "text_line");
		ptrdiff_t mi = 0;
		i = 0;

		while ((*str)[i]) {
			if ((bad_char = BLI_utf8_invalid_byte((*str) + i, length - i)) == -1) {
				memcpy(newstr + mi, (*str) + i, length - i + 1);
				break;
			}

			memcpy(newstr + mi, (*str) + i, bad_char);

			BLI_str_utf8_from_unicode((*str)[i + bad_char], newstr + mi + bad_char);
			i += bad_char + 1;
			mi += bad_char + 2;
		}
		newstr[length + added] = '\0';
		MEM_freeN(*str);
		*str = newstr;
	}

	return added;
}

// this function removes any control characters from
// a textline and fixes invalid utf-8 sequences

static void cleanup_textline(TextLine *tl)
{
	int i;

	for (i = 0; i < tl->len; i++) {
		if (tl->line[i] < ' ' && tl->line[i] != '\t') {
			memmove(tl->line + i, tl->line + i + 1, tl->len - i);
			tl->len--;
			i--;
		}
	}
	tl->len += txt_extended_ascii_as_utf8(&tl->line);
}

/**
 * used for load and reload (unlike txt_insert_buf)
 * assumes all fields are empty
 */
static void text_from_buf(Text *text, const unsigned char *buffer, const int len)
{
	int i, llen;

	BLI_assert(BLI_listbase_is_empty(&text->lines));

	text->nlines = 0;
	llen = 0;
	for (i = 0; i < len; i++) {
		if (buffer[i] == '\n') {
			TextLine *tmp;

			tmp = (TextLine *) MEM_mallocN(sizeof(TextLine), "textline");
			tmp->line = (char *) MEM_mallocN(llen + 1, "textline_string");
			tmp->format = NULL;

			if (llen) memcpy(tmp->line, &buffer[i - llen], llen);
			tmp->line[llen] = 0;
			tmp->len = llen;

			cleanup_textline(tmp);

			BLI_addtail(&text->lines, tmp);
			text->nlines++;

			llen = 0;
			continue;
		}
		llen++;
	}

	/* create new line in cases:
	 * - rest of line (if last line in file hasn't got \n terminator).
	 *   in this case content of such line would be used to fill text line buffer
	 * - file is empty. in this case new line is needed to start editing from.
	 * - last character in buffer is \n. in this case new line is needed to
	 *   deal with newline at end of file. (see [#28087]) (sergey) */
	if (llen != 0 || text->nlines == 0 || buffer[len - 1] == '\n') {
		TextLine *tmp;

		tmp = (TextLine *) MEM_mallocN(sizeof(TextLine), "textline");
		tmp->line = (char *) MEM_mallocN(llen + 1, "textline_string");
		tmp->format = NULL;

		if (llen) memcpy(tmp->line, &buffer[i - llen], llen);

		tmp->line[llen] = 0;
		tmp->len = llen;

		cleanup_textline(tmp);

		BLI_addtail(&text->lines, tmp);
		text->nlines++;
	}

	text->curl = text->sell = text->lines.first;
	text->curc = text->selc = 0;
}

bool BKE_text_reload(Text *text)
{
	unsigned char *buffer;
	size_t buffer_len;
	char filepath_abs[FILE_MAX];
	BLI_stat_t st;

	if (!text->name) {
		return false;
	}

	BLI_strncpy(filepath_abs, text->name, FILE_MAX);
	BLI_path_abs(filepath_abs, BKE_main_blendfile_path_from_global());

	buffer = BLI_file_read_text_as_mem(filepath_abs, 0, &buffer_len);
	if (buffer == NULL) {
		return false;
	}

	/* free memory: */
	BKE_text_free_lines(text);
	txt_make_dirty(text);

	/* clear undo buffer */
	if (BLI_stat(filepath_abs, &st) != -1) {
		text->mtime = st.st_mtime;
	}
	else {
		text->mtime = 0;
	}

	text_from_buf(text, buffer, buffer_len);

	MEM_freeN(buffer);
	return true;
}

Text *BKE_text_load_ex(Main *bmain, const char *file, const char *relpath, const bool is_internal)
{
	unsigned char *buffer;
	size_t buffer_len;
	Text *ta;
	char filepath_abs[FILE_MAX];
	BLI_stat_t st;

	BLI_strncpy(filepath_abs, file, FILE_MAX);
	if (relpath) /* can be NULL (bg mode) */
		BLI_path_abs(filepath_abs, relpath);

	buffer = BLI_file_read_text_as_mem(filepath_abs, 0, &buffer_len);
	if (buffer == NULL) {
		return false;
	}

	ta = BKE_libblock_alloc(bmain, ID_TXT, BLI_path_basename(filepath_abs), 0);
	ta->id.us = 0;

	BLI_listbase_clear(&ta->lines);
	ta->curl = ta->sell = NULL;

	if ((U.flag & USER_TXT_TABSTOSPACES_DISABLE) == 0)
		ta->flags = TXT_TABSTOSPACES;

	if (is_internal == false) {
		ta->name = MEM_mallocN(strlen(file) + 1, "text_name");
		strcpy(ta->name, file);
	}
	else {
		ta->flags |= TXT_ISMEM | TXT_ISDIRTY;
	}

	/* clear undo buffer */
	if (BLI_stat(filepath_abs, &st) != -1) {
		ta->mtime = st.st_mtime;
	}
	else {
		ta->mtime = 0;
	}

	text_from_buf(ta, buffer, buffer_len);

	MEM_freeN(buffer);

	return ta;
}

Text *BKE_text_load(Main *bmain, const char *file, const char *relpath)
{
	return BKE_text_load_ex(bmain, file, relpath, false);
}

/**
 * Only copy internal data of Text ID from source to already allocated/initialized destination.
 * You probably nerver want to use that directly, use id_copy or BKE_id_copy_ex for typical needs.
 *
 * WARNING! This function will not handle ID user count!
 *
 * \param flag: Copying options (see BKE_library.h's LIB_ID_COPY_... flags for more).
 */
void BKE_text_copy_data(Main *UNUSED(bmain), Text *ta_dst, const Text *ta_src, const int UNUSED(flag))
{
	/* file name can be NULL */
	if (ta_src->name) {
		ta_dst->name = BLI_strdup(ta_src->name);
	}

	ta_dst->flags |= TXT_ISDIRTY;

	BLI_listbase_clear(&ta_dst->lines);
	ta_dst->curl = ta_dst->sell = NULL;
	ta_dst->compiled = NULL;

	/* Walk down, reconstructing */
	for (TextLine *line_src = ta_src->lines.first; line_src; line_src = line_src->next) {
		TextLine *line_dst = MEM_mallocN(sizeof(*line_dst), __func__);

		line_dst->line = BLI_strdup(line_src->line);
		line_dst->format = NULL;
		line_dst->len = line_src->len;

		BLI_addtail(&ta_dst->lines, line_dst);
	}

	ta_dst->curl = ta_dst->sell = ta_dst->lines.first;
	ta_dst->curc = ta_dst->selc = 0;
}

Text *BKE_text_copy(Main *bmain, const Text *ta)
{
	Text *ta_copy;
	BKE_id_copy_ex(bmain, &ta->id, (ID **)&ta_copy, 0);
	return ta_copy;
}

void BKE_text_make_local(Main *bmain, Text *text, const bool lib_local)
{
	BKE_id_make_local_generic(bmain, &text->id, true, lib_local);
}

void BKE_text_clear(Text *text, TextUndoBuf *utxt) /* called directly from rna */
{
	const bool undoing_orig = undoing;
	undoing = (utxt == NULL);

	txt_sel_all(text);
	txt_delete_sel(text, utxt);

	undoing = undoing_orig;

	txt_make_dirty(text);
}

void BKE_text_write(Text *text, TextUndoBuf *utxt, const char *str) /* called directly from rna */
{
	const bool undoing_orig = undoing;
	undoing = (utxt == NULL);

	txt_insert_buf(text, utxt, str);
	txt_move_eof(text, 0);

	undoing = undoing_orig;

	txt_make_dirty(text);
}


/* returns 0 if file on disk is the same or Text is in memory only
 * returns 1 if file has been modified on disk since last local edit
 * returns 2 if file on disk has been deleted
 * -1 is returned if an error occurs */

int BKE_text_file_modified_check(Text *text)
{
	BLI_stat_t st;
	int result;
	char file[FILE_MAX];

	if (!text->name)
		return 0;

	BLI_strncpy(file, text->name, FILE_MAX);
	BLI_path_abs(file, BKE_main_blendfile_path_from_global());

	if (!BLI_exists(file))
		return 2;

	result = BLI_stat(file, &st);

	if (result == -1)
		return -1;

	if ((st.st_mode & S_IFMT) != S_IFREG)
		return -1;

	if (st.st_mtime > text->mtime)
		return 1;

	return 0;
}

void BKE_text_file_modified_ignore(Text *text)
{
	BLI_stat_t st;
	int result;
	char file[FILE_MAX];

	if (!text->name) return;

	BLI_strncpy(file, text->name, FILE_MAX);
	BLI_path_abs(file, BKE_main_blendfile_path_from_global());

	if (!BLI_exists(file)) return;

	result = BLI_stat(file, &st);

	if (result == -1 || (st.st_mode & S_IFMT) != S_IFREG)
		return;

	text->mtime = st.st_mtime;
}

/*****************************/
/* Editing utility functions */
/*****************************/

static void make_new_line(TextLine *line, char *newline)
{
	if (line->line) MEM_freeN(line->line);
	if (line->format) MEM_freeN(line->format);

	line->line = newline;
	line->len = strlen(newline);
	line->format = NULL;
}

static TextLine *txt_new_line(const char *str)
{
	TextLine *tmp;

	if (!str) str = "";

	tmp = (TextLine *) MEM_mallocN(sizeof(TextLine), "textline");
	tmp->line = MEM_mallocN(strlen(str) + 1, "textline_string");
	tmp->format = NULL;

	strcpy(tmp->line, str);

	tmp->len = strlen(str);
	tmp->next = tmp->prev = NULL;

	return tmp;
}

static TextLine *txt_new_linen(const char *str, int n)
{
	TextLine *tmp;

	tmp = (TextLine *) MEM_mallocN(sizeof(TextLine), "textline");
	tmp->line = MEM_mallocN(n + 1, "textline_string");
	tmp->format = NULL;

	BLI_strncpy(tmp->line, (str) ? str : "", n + 1);

	tmp->len = strlen(tmp->line);
	tmp->next = tmp->prev = NULL;

	return tmp;
}

void txt_clean_text(Text *text)
{
	TextLine **top, **bot;

	if (!text->lines.first) {
		if (text->lines.last) text->lines.first = text->lines.last;
		else text->lines.first = text->lines.last = txt_new_line(NULL);
	}

	if (!text->lines.last) text->lines.last = text->lines.first;

	top = (TextLine **) &text->lines.first;
	bot = (TextLine **) &text->lines.last;

	while ((*top)->prev) *top = (*top)->prev;
	while ((*bot)->next) *bot = (*bot)->next;

	if (!text->curl) {
		if (text->sell) text->curl = text->sell;
		else text->curl = text->lines.first;
		text->curc = 0;
	}

	if (!text->sell) {
		text->sell = text->curl;
		text->selc = 0;
	}
}

int txt_get_span(TextLine *from, TextLine *to)
{
	int ret = 0;
	TextLine *tmp = from;

	if (!to || !from) return 0;
	if (from == to) return 0;

	/* Look forwards */
	while (tmp) {
		if (tmp == to) return ret;
		ret++;
		tmp = tmp->next;
	}

	/* Look backwards */
	if (!tmp) {
		tmp = from;
		ret = 0;
		while (tmp) {
			if (tmp == to) break;
			ret--;
			tmp = tmp->prev;
		}
		if (!tmp) ret = 0;
	}

	return ret;
}

static void txt_make_dirty(Text *text)
{
	text->flags |= TXT_ISDIRTY;
#ifdef WITH_PYTHON
	if (text->compiled) BPY_text_free_code(text);
#endif
}

/****************************/
/* Cursor utility functions */
/****************************/

static void txt_curs_cur(Text *text, TextLine ***linep, int **charp)
{
	*linep = &text->curl; *charp = &text->curc;
}

static void txt_curs_sel(Text *text, TextLine ***linep, int **charp)
{
	*linep = &text->sell; *charp = &text->selc;
}

bool txt_cursor_is_line_start(Text *text)
{
	return (text->selc == 0);
}

bool txt_cursor_is_line_end(Text *text)
{
	return (text->selc == text->sell->len);
}

/*****************************/
/* Cursor movement functions */
/*****************************/

int txt_utf8_offset_to_index(const char *str, int offset)
{
	int index = 0, pos = 0;
	while (pos != offset) {
		pos += BLI_str_utf8_size(str + pos);
		index++;
	}
	return index;
}

int txt_utf8_index_to_offset(const char *str, int index)
{
	int offset = 0, pos = 0;
	while (pos != index) {
		offset += BLI_str_utf8_size(str + offset);
		pos++;
	}
	return offset;
}

int txt_utf8_offset_to_column(const char *str, int offset)
{
	int column = 0, pos = 0;
	while (pos < offset) {
		column += BLI_str_utf8_char_width_safe(str + pos);
		pos += BLI_str_utf8_size_safe(str + pos);
	}
	return column;
}

int txt_utf8_column_to_offset(const char *str, int column)
{
	int offset = 0, pos = 0, col;
	while (*(str + offset) && pos < column) {
		col = BLI_str_utf8_char_width_safe(str + offset);
		if (pos + col > column)
			break;
		offset += BLI_str_utf8_size_safe(str + offset);
		pos += col;
	}
	return offset;
}

void txt_move_up(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_first(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	if ((*linep)->prev) {
		int column = txt_utf8_offset_to_column((*linep)->line, *charp);
		*linep = (*linep)->prev;
		*charp = txt_utf8_column_to_offset((*linep)->line, column);

	}
	else {
		txt_move_bol(text, sel);
	}

	if (!sel) txt_pop_sel(text);
}

void txt_move_down(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_last(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	if ((*linep)->next) {
		int column = txt_utf8_offset_to_column((*linep)->line, *charp);
		*linep = (*linep)->next;
		*charp = txt_utf8_column_to_offset((*linep)->line, column);
	}
	else {
		txt_move_eol(text, sel);
	}

	if (!sel) txt_pop_sel(text);
}

int txt_calc_tab_left(TextLine *tl, int ch)
{
	/* do nice left only if there are only spaces */

	int tabsize = (ch < TXT_TABSIZE) ? ch : TXT_TABSIZE;

	for (int i = 0; i < ch; i++)
		if (tl->line[i] != ' ') {
			tabsize = 0;
			break;
		}

	/* if in the middle of the space-tab */
	if (tabsize && ch % TXT_TABSIZE != 0)
		tabsize = (ch % TXT_TABSIZE);
	return tabsize;
}

int txt_calc_tab_right(TextLine *tl, int ch)
{
	if (tl->line[ch] == ' ') {
		int i;
		for (i = 0; i < ch; i++) {
			if (tl->line[i] != ' ') {
				return 0;
			}
		}

		int tabsize = (ch) % TXT_TABSIZE + 1;
		for (i = ch + 1; tl->line[i] == ' ' && tabsize < TXT_TABSIZE; i++) {
			tabsize++;
		}

		return i - ch;
	}
	else {
		return 0;
	}
}

void txt_move_left(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;
	int tabsize = 0;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_first(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	if (*charp == 0) {
		if ((*linep)->prev) {
			txt_move_up(text, sel);
			*charp = (*linep)->len;
		}
	}
	else {
		/* do nice left only if there are only spaces */
		// TXT_TABSIZE hardcoded in DNA_text_types.h
		if (text->flags & TXT_TABSTOSPACES) {
			tabsize = txt_calc_tab_left(*linep, *charp);
		}

		if (tabsize) {
			(*charp) -= tabsize;
		}
		else {
			const char *prev = BLI_str_prev_char_utf8((*linep)->line + *charp);
			*charp = prev - (*linep)->line;
		}
	}

	if (!sel) txt_pop_sel(text);
}

void txt_move_right(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_last(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	if (*charp == (*linep)->len) {
		if ((*linep)->next) {
			txt_move_down(text, sel);
			*charp = 0;
		}
	}
	else {
		/* do nice right only if there are only spaces */
		/* spaces hardcoded in DNA_text_types.h */
		int tabsize = 0;

		if (text->flags & TXT_TABSTOSPACES) {
			tabsize = txt_calc_tab_right(*linep, *charp);
		}

		if (tabsize) {
			(*charp) += tabsize;
		}
		else {
			(*charp) += BLI_str_utf8_size((*linep)->line + *charp);
		}
	}

	if (!sel) txt_pop_sel(text);
}

void txt_jump_left(Text *text, const bool sel, const bool use_init_step)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_first(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	BLI_str_cursor_step_utf8((*linep)->line, (*linep)->len,
	                         charp, STRCUR_DIR_PREV,
	                         STRCUR_JUMP_DELIM, use_init_step);

	if (!sel) txt_pop_sel(text);
}

void txt_jump_right(Text *text, const bool sel, const bool use_init_step)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else { txt_pop_last(text); txt_curs_cur(text, &linep, &charp); }
	if (!*linep) return;

	BLI_str_cursor_step_utf8((*linep)->line, (*linep)->len,
	                         charp, STRCUR_DIR_NEXT,
	                         STRCUR_JUMP_DELIM, use_init_step);

	if (!sel) txt_pop_sel(text);
}

void txt_move_bol(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;

	*charp = 0;

	if (!sel) txt_pop_sel(text);
}

void txt_move_eol(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;

	*charp = (*linep)->len;

	if (!sel) txt_pop_sel(text);
}

void txt_move_bof(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;

	*linep = text->lines.first;
	*charp = 0;

	if (!sel) txt_pop_sel(text);
}

void txt_move_eof(Text *text, const bool sel)
{
	TextLine **linep;
	int *charp;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;

	*linep = text->lines.last;
	*charp = (*linep)->len;

	if (!sel) txt_pop_sel(text);
}

void txt_move_toline(Text *text, unsigned int line, const bool sel)
{
	txt_move_to(text, line, 0, sel);
}

/* Moves to a certain byte in a line, not a certain utf8-character! */
void txt_move_to(Text *text, unsigned int line, unsigned int ch, const bool sel)
{
	TextLine **linep;
	int *charp;
	unsigned int i;

	if (sel) txt_curs_sel(text, &linep, &charp);
	else txt_curs_cur(text, &linep, &charp);
	if (!*linep) return;

	*linep = text->lines.first;
	for (i = 0; i < line; i++) {
		if ((*linep)->next) *linep = (*linep)->next;
		else break;
	}
	if (ch > (unsigned int)((*linep)->len))
		ch = (unsigned int)((*linep)->len);
	*charp = ch;

	if (!sel) txt_pop_sel(text);
}

/****************************/
/* Text selection functions */
/****************************/

static void txt_curs_swap(Text *text)
{
	TextLine *tmpl;
	int tmpc;

	tmpl = text->curl;
	text->curl = text->sell;
	text->sell = tmpl;

	tmpc = text->curc;
	text->curc = text->selc;
	text->selc = tmpc;
}

static void txt_pop_first(Text *text)
{
	if (txt_get_span(text->curl, text->sell) < 0 ||
	    (text->curl == text->sell && text->curc > text->selc))
	{
		txt_curs_swap(text);
	}

	txt_pop_sel(text);
}

static void txt_pop_last(Text *text)
{
	if (txt_get_span(text->curl, text->sell) > 0 ||
	    (text->curl == text->sell && text->curc < text->selc))
	{
		txt_curs_swap(text);
	}

	txt_pop_sel(text);
}

void txt_pop_sel(Text *text)
{
	text->sell = text->curl;
	text->selc = text->curc;
}

void txt_order_cursors(Text *text, const bool reverse)
{
	if (!text->curl) return;
	if (!text->sell) return;

	/* Flip so text->curl is before/after text->sell */
	if (reverse == false) {
		if ((txt_get_span(text->curl, text->sell) < 0) ||
		    (text->curl == text->sell && text->curc > text->selc))
		{
			txt_curs_swap(text);
		}
	}
	else {
		if ((txt_get_span(text->curl, text->sell) > 0) ||
		    (text->curl == text->sell && text->curc < text->selc))
		{
			txt_curs_swap(text);
		}
	}
}

bool txt_has_sel(Text *text)
{
	return ((text->curl != text->sell) || (text->curc != text->selc));
}

static void txt_delete_sel(Text *text, TextUndoBuf *utxt)
{
	TextLine *tmpl;
	char *buf;

	if (!text->curl) return;
	if (!text->sell) return;

	if (!txt_has_sel(text)) return;

	txt_order_cursors(text, false);

	if (!undoing) {
		buf = txt_sel_to_buf(text);
		txt_undo_add_blockop(text, utxt, UNDO_DBLOCK, buf);
		MEM_freeN(buf);
	}

	buf = MEM_mallocN(text->curc + (text->sell->len - text->selc) + 1, "textline_string");

	strncpy(buf, text->curl->line, text->curc);
	strcpy(buf + text->curc, text->sell->line + text->selc);
	buf[text->curc + (text->sell->len - text->selc)] = 0;

	make_new_line(text->curl, buf);

	tmpl = text->sell;
	while (tmpl != text->curl) {
		tmpl = tmpl->prev;
		if (!tmpl) break;

		txt_delete_line(text, tmpl->next);
	}

	text->sell = text->curl;
	text->selc = text->curc;
}

void txt_sel_all(Text *text)
{
	text->curl = text->lines.first;
	text->curc = 0;

	text->sell = text->lines.last;
	text->selc = text->sell->len;
}

/**
 * Reverse of #txt_pop_sel
 * Clears the selection and ensures the cursor is located
 * at the selection (where the cursor is visually while editing).
 */
void txt_sel_clear(Text *text)
{
	if (text->sell) {
		text->curl = text->sell;
		text->curc = text->selc;
	}
}

void txt_sel_line(Text *text)
{
	if (!text->curl) return;

	text->curc = 0;
	text->sell = text->curl;
	text->selc = text->sell->len;
}

/***************************/
/* Cut and paste functions */
/***************************/

char *txt_to_buf(Text *text)
{
	int length;
	TextLine *tmp, *linef, *linel;
	int charf, charl;
	char *buf;

	if (!text->curl) return NULL;
	if (!text->sell) return NULL;
	if (!text->lines.first) return NULL;

	linef = text->lines.first;
	charf = 0;

	linel = text->lines.last;
	charl = linel->len;

	if (linef == text->lines.last) {
		length = charl - charf;

		buf = MEM_mallocN(length + 2, "text buffer");

		BLI_strncpy(buf, linef->line + charf, length + 1);
		buf[length] = 0;
	}
	else {
		length = linef->len - charf;
		length += charl;
		length += 2; /* For the 2 '\n' */

		tmp = linef->next;
		while (tmp && tmp != linel) {
			length += tmp->len + 1;
			tmp = tmp->next;
		}

		buf = MEM_mallocN(length + 1, "cut buffer");

		strncpy(buf, linef->line + charf, linef->len - charf);
		length = linef->len - charf;

		buf[length++] = '\n';

		tmp = linef->next;
		while (tmp && tmp != linel) {
			strncpy(buf + length, tmp->line, tmp->len);
			length += tmp->len;

			buf[length++] = '\n';

			tmp = tmp->next;
		}
		strncpy(buf + length, linel->line, charl);
		length += charl;

		/* python compiler wants an empty end line */
		buf[length++] = '\n';
		buf[length] = 0;
	}

	return buf;
}

int txt_find_string(Text *text, const char *findstr, int wrap, int match_case)
{
	TextLine *tl, *startl;
	const char *s = NULL;

	if (!text->curl || !text->sell) return 0;

	txt_order_cursors(text, false);

	tl = startl = text->sell;

	if (match_case) s = strstr(&tl->line[text->selc], findstr);
	else s = BLI_strcasestr(&tl->line[text->selc], findstr);
	while (!s) {
		tl = tl->next;
		if (!tl) {
			if (wrap)
				tl = text->lines.first;
			else
				break;
		}

		if (match_case) s = strstr(tl->line, findstr);
		else s = BLI_strcasestr(tl->line, findstr);
		if (tl == startl)
			break;
	}

	if (s) {
		int newl = txt_get_span(text->lines.first, tl);
		int newc = (int)(s - tl->line);
		txt_move_to(text, newl, newc, 0);
		txt_move_to(text, newl, newc + strlen(findstr), 1);
		return 1;
	}
	else
		return 0;
}

char *txt_sel_to_buf(Text *text)
{
	char *buf;
	int length = 0;
	TextLine *tmp, *linef, *linel;
	int charf, charl;

	if (!text->curl) return NULL;
	if (!text->sell) return NULL;

	if (text->curl == text->sell) {
		linef = linel = text->curl;

		if (text->curc < text->selc) {
			charf = text->curc;
			charl = text->selc;
		}
		else {
			charf = text->selc;
			charl = text->curc;
		}
	}
	else if (txt_get_span(text->curl, text->sell) < 0) {
		linef = text->sell;
		linel = text->curl;

		charf = text->selc;
		charl = text->curc;
	}
	else {
		linef = text->curl;
		linel = text->sell;

		charf = text->curc;
		charl = text->selc;
	}

	if (linef == linel) {
		length = charl - charf;

		buf = MEM_mallocN(length + 1, "sel buffer");

		BLI_strncpy(buf, linef->line + charf, length + 1);
	}
	else {
		length += linef->len - charf;
		length += charl;
		length++; /* For the '\n' */

		tmp = linef->next;
		while (tmp && tmp != linel) {
			length += tmp->len + 1;
			tmp = tmp->next;
		}

		buf = MEM_mallocN(length + 1, "sel buffer");

		strncpy(buf, linef->line + charf, linef->len - charf);
		length = linef->len - charf;

		buf[length++] = '\n';

		tmp = linef->next;
		while (tmp && tmp != linel) {
			strncpy(buf + length, tmp->line, tmp->len);
			length += tmp->len;

			buf[length++] = '\n';

			tmp = tmp->next;
		}
		strncpy(buf + length, linel->line, charl);
		length += charl;

		buf[length] = 0;
	}

	return buf;
}

void txt_insert_buf(Text *text, TextUndoBuf *utxt, const char *in_buffer)
{
	const bool undoing_orig = undoing;
	int l = 0, len;
	size_t i = 0, j;
	TextLine *add;
	char *buffer;

	if (!in_buffer) return;

	txt_delete_sel(text, utxt);

	len = strlen(in_buffer);
	buffer = BLI_strdupn(in_buffer, len);
	len += txt_extended_ascii_as_utf8(&buffer);

	if (!undoing) {
		txt_undo_add_blockop(text, utxt, UNDO_IBLOCK, buffer);
	}
	undoing = true;

	/* Read the first line (or as close as possible */
	while (buffer[i] && buffer[i] != '\n') {
		txt_add_raw_char(text, utxt, BLI_str_utf8_as_unicode_step(buffer, &i));
	}

	if (buffer[i] == '\n') {
		txt_split_curline(text, utxt);
		i++;

		while (i < len) {
			l = 0;

			while (buffer[i] && buffer[i] != '\n') {
				i++;
				l++;
			}

			if (buffer[i] == '\n') {
				add = txt_new_linen(buffer + (i - l), l);
				BLI_insertlinkbefore(&text->lines, text->curl, add);
				i++;
			}
			else {
				for (j = i - l; j < i && j < len; ) {
					txt_add_raw_char(text, utxt, BLI_str_utf8_as_unicode_step(buffer, &j));
				}
				break;
			}
		}
	}

	MEM_freeN(buffer);
	undoing = undoing_orig;
}

/******************/
/* Undo functions */
/******************/

static bool max_undo_test(TextUndoBuf *utxt, int x)
{
	/* Normally over-allocating is preferred,
	 * however in this case the buffer is small enough and re-allocation
	 * fast enough for each undo step that it's not a problem to allocate each time.
	 * This also saves on some memory when we have many text buffers
	 * that would have an empty undo memory allocated.
	 */

	/* Add one for the null terminator. */
	utxt->len = utxt->pos + x + 1;
	if (utxt->len > TXT_MAX_UNDO) {
		/* XXX error("Undo limit reached, buffer cleared\n"); */
		MEM_freeN(utxt->buf);
		return false;
	}
	else {
		/* Small reallocations on each undo step is fine. */
		utxt->buf = MEM_recallocN(utxt->buf, utxt->len);
	}
	return true;
}

static void txt_undo_end(Text *UNUSED(text), TextUndoBuf *utxt)
{
	int undo_pos_end = utxt->pos + 1;
	BLI_assert(undo_pos_end + 1 == utxt->len);
	utxt->buf[undo_pos_end] = '\0';
}

/* Call once undo is done. */
#ifndef NDEBUG

#endif

#if 0  /* UNUSED */
static void dump_buffer(TextUndoBuf *utxt)
{
	int i = 0;

	while (i++ < utxt->undo_pos) printf("%d: %d %c\n", i, utxt->buf[i], utxt->buf[i]);
}

/* Note: this function is outdated and must be updated if needed for future use */
void txt_print_undo(Text *text)
{
	int i = 0;
	int op;
	const char *ops;
	int linep, charp;

	dump_buffer(text);

	printf("---< Undo Buffer >---\n");

	printf("UndoPosition is %d\n", utxt->pos);

	while (i <= utxt->pos) {
		op = utxt->buf[i];

		if (op == UNDO_INSERT_1) {
			ops = "Insert ascii ";
		}
		else if (op == UNDO_INSERT_2) {
			ops = "Insert 2 bytes ";
		}
		else if (op == UNDO_INSERT_3) {
			ops = "Insert 3 bytes ";
		}
		else if (op == UNDO_INSERT_4) {
			ops = "Insert unicode ";
		}
		else if (op == UNDO_BS_1) {
			ops = "Backspace for ascii ";
		}
		else if (op == UNDO_BS_2) {
			ops = "Backspace for 2 bytes ";
		}
		else if (op == UNDO_BS_3) {
			ops = "Backspace for 3 bytes ";
		}
		else if (op == UNDO_BS_4) {
			ops = "Backspace for unicode ";
		}
		else if (op == UNDO_DEL_1) {
			ops = "Delete ascii ";
		}
		else if (op == UNDO_DEL_2) {
			ops = "Delete 2 bytes ";
		}
		else if (op == UNDO_DEL_3) {
			ops = "Delete 3 bytes ";
		}
		else if (op == UNDO_DEL_4) {
			ops = "Delete unicode ";
		}
		else if (op == UNDO_DBLOCK) {
			ops = "Delete text block";
		}
		else if (op == UNDO_IBLOCK) {
			ops = "Insert text block";
		}
		else if (op == UNDO_INDENT) {
			ops = "Indent ";
		}
		else if (op == UNDO_UNINDENT) {
			ops = "Unindent ";
		}
		else if (op == UNDO_COMMENT) {
			ops = "Comment ";
		}
		else if (op == UNDO_UNCOMMENT) {
			ops = "Uncomment ";
		}
		else {
			ops = "Unknown";
		}

		printf("Op (%o) at %d = %s", op, i, ops);
		if (op >= UNDO_INSERT_1 && op <= UNDO_DEL_4) {
			i++;
			printf(" - Char is ");
			switch (op) {
				case UNDO_INSERT_1: case UNDO_BS_1: case UNDO_DEL_1:
					printf("%c", utxt->buf[i]);
					i++;
					break;
				case UNDO_INSERT_2: case UNDO_BS_2: case UNDO_DEL_2:
					printf("%c%c", utxt->buf[i], utxt->buf[i + 1]);
					i += 2;
					break;
				case UNDO_INSERT_3: case UNDO_BS_3: case UNDO_DEL_3:
					printf("%c%c%c", utxt->buf[i], utxt->buf[i + 1], utxt->buf[i + 2]);
					i += 3;
					break;
				case UNDO_INSERT_4: case UNDO_BS_4: case UNDO_DEL_4:
				{
					unsigned int uc;
					char c[BLI_UTF8_MAX + 1];
					size_t c_len;
					uc = utxt->buf[i]; i++;
					uc = uc + (utxt->buf[i] << 8); i++;
					uc = uc + (utxt->buf[i] << 16); i++;
					uc = uc + (utxt->buf[i] << 24); i++;
					c_len = BLI_str_utf8_from_unicode(uc, c);
					c[c_len] = '\0';
					puts(c);
					break;
				}
			}
		}
		else if (op == UNDO_DBLOCK || op == UNDO_IBLOCK) {
			i++;

			linep = utxt->buf[i]; i++;
			linep = linep + (utxt->buf[i] << 8); i++;
			linep = linep + (utxt->buf[i] << 16); i++;
			linep = linep + (utxt->buf[i] << 24); i++;

			printf(" (length %d) <", linep);

			while (linep > 0) {
				putchar(utxt->buf[i]);
				linep--; i++;
			}

			linep = utxt->buf[i]; i++;
			linep = linep + (utxt->buf[i] << 8); i++;
			linep = linep + (utxt->buf[i] << 16); i++;
			linep = linep + (utxt->buf[i] << 24); i++;
			printf("> (%d)", linep);
		}
		else if (op == UNDO_INDENT || op == UNDO_UNINDENT) {
			i++;

			charp = utxt->buf[i]; i++;
			charp = charp + (utxt->buf[i] << 8); i++;

			linep = utxt->buf[i]; i++;
			linep = linep + (utxt->buf[i] << 8); i++;
			linep = linep + (utxt->buf[i] << 16); i++;
			linep = linep + (utxt->buf[i] << 24); i++;

			printf("to <%d, %d> ", linep, charp);

			charp = utxt->buf[i]; i++;
			charp = charp + (utxt->buf[i] << 8); i++;

			linep = utxt->buf[i]; i++;
			linep = linep + (utxt->buf[i] << 8); i++;
			linep = linep + (utxt->buf[i] << 16); i++;
			linep = linep + (utxt->buf[i] << 24); i++;

			printf("from <%d, %d>", linep, charp);
		}

		printf(" %d\n",  i);
		i++;
	}
}
#endif

static void txt_undo_store_uint16(char *undo_buf, int *undo_pos, unsigned short value)
{
	undo_buf[*undo_pos] = (value) & 0xff;
	(*undo_pos)++;
	undo_buf[*undo_pos] = (value >> 8) & 0xff;
	(*undo_pos)++;
}

static void txt_undo_store_uint32(char *undo_buf, int *undo_pos, unsigned int value)
{
	undo_buf[*undo_pos] = (value) & 0xff;
	(*undo_pos)++;
	undo_buf[*undo_pos] = (value >> 8) & 0xff;
	(*undo_pos)++;
	undo_buf[*undo_pos] = (value >> 16) & 0xff;
	(*undo_pos)++;
	undo_buf[*undo_pos] = (value >> 24) & 0xff;
	(*undo_pos)++;
}

/* store the cur cursor to the undo buffer (6 bytes)*/
static void txt_undo_store_cur(Text *text, TextUndoBuf *utxt)
{
	txt_undo_store_uint16(utxt->buf, &utxt->pos, text->curc);
	txt_undo_store_uint32(utxt->buf, &utxt->pos, txt_get_span(text->lines.first, text->curl));
}

/* store the sel cursor to the undo buffer (6 bytes) */
static void txt_undo_store_sel(Text *text, TextUndoBuf *utxt)
{
	txt_undo_store_uint16(utxt->buf, &utxt->pos, text->selc);
	txt_undo_store_uint32(utxt->buf, &utxt->pos, txt_get_span(text->lines.first, text->sell));
}

/* store both cursors to the undo buffer (12 bytes) */
static void txt_undo_store_cursors(Text *text, TextUndoBuf *utxt)
{
	txt_undo_store_cur(text, utxt);
	txt_undo_store_sel(text, utxt);
}

/* store an operator along with a block of data */
static void txt_undo_add_blockop(Text *text, TextUndoBuf *utxt, int op, const char *buf)
{
	unsigned int length = strlen(buf);

	if (!max_undo_test(utxt, 2 + 12 + 4 + length + 4 + 1)) {
		return;
	}
	/* 2 bytes */
	utxt->pos++;
	utxt->buf[utxt->pos] = op;
	utxt->pos++;
	/* 12 bytes */
	txt_undo_store_cursors(text, utxt);
	/* 4 bytes */
	txt_undo_store_uint32(utxt->buf, &utxt->pos, length);
	/* 'length' bytes */
	memcpy(utxt->buf + utxt->pos, buf, length);
	utxt->pos += length;
	/* 4 bytes */
	txt_undo_store_uint32(utxt->buf, &utxt->pos, length);
	/* 1 byte */
	utxt->buf[utxt->pos] = op;

	txt_undo_end(text, utxt);
}

/* store a regular operator */
void txt_undo_add_op(Text *text, TextUndoBuf *utxt, int op)
{
	if (!max_undo_test(utxt, 2 + 12 + 1)) {
		return;
	}

	/* 2 bytes */
	utxt->pos++;
	utxt->buf[utxt->pos] = op;
	utxt->pos++;
	/* 12 bytes */
	txt_undo_store_cursors(text, utxt);
	/* 1 byte */
	utxt->buf[utxt->pos] = op;

	txt_undo_end(text, utxt);
}

/* store an operator for a single character */
static void txt_undo_add_charop(Text *text, TextUndoBuf *utxt, int op_start, unsigned int c)
{
	char utf8[BLI_UTF8_MAX];
	size_t i, utf8_size = BLI_str_utf8_from_unicode(c, utf8);

	if (utf8_size < 4 && 0) {
		if (!max_undo_test(utxt, 2 + 6 + utf8_size + 1)) {
			return;
		}
		/* 2 bytes */
		utxt->pos++;
		utxt->buf[utxt->pos] = op_start + utf8_size - 1;
		utxt->pos++;
		/* 6 bytes */
		txt_undo_store_cur(text, utxt);
		/* 'utf8_size' bytes */
		for (i = 0; i < utf8_size; i++) {
			utxt->buf[utxt->pos] = utf8[i];
			utxt->pos++;
		}
		/* 1 byte */
		utxt->buf[utxt->pos] = op_start + utf8_size - 1;
	}
	else {
		if (!max_undo_test(utxt, 2 + 6 + 4 + 1)) {
			return;
		}
		/* 2 bytes */
		utxt->pos++;
		utxt->buf[utxt->pos] = op_start + 3;
		utxt->pos++;
		/* 6 bytes */
		txt_undo_store_cur(text, utxt);
		/* 4 bytes */
		txt_undo_store_uint32(utxt->buf, &utxt->pos, c);
		/* 1 byte */
		utxt->buf[utxt->pos] = op_start + 3;
	}

	txt_undo_end(text, utxt);
}

/* extends Link */
struct LinkInt {
	struct LinkInt *next, *prev;
	int value;
};

/**
 * UnindentLines points to a #ListBase composed of #LinkInt elements, listing the numbers
 * of the lines that should not be indented back.
 */
static void txt_undo_add_unprefix_op(
        Text *text, TextUndoBuf *utxt, char undo_op,
        const ListBase *line_index_mask, const int line_index_mask_len)
{
	struct LinkInt *idata;

	BLI_assert(BLI_listbase_count(line_index_mask) == line_index_mask_len);

	/* OP byte + UInt32 count + counted UInt32 line numbers + UInt32 count + 12-bytes selection + OP byte */
	if (!max_undo_test(utxt, 2 + 4 + (line_index_mask_len * 4) + 4 + 12 + 1)) {
		return;
	}

	/* 2 bytes */
	utxt->pos++;
	utxt->buf[utxt->pos] = undo_op;
	utxt->pos++;
	/* Adding number of line numbers to read
	 * 4 bytes */
	txt_undo_store_uint32(utxt->buf, &utxt->pos, line_index_mask_len);

	/* Adding linenumbers of lines that shall not be indented if undoing.
	 * 'line_index_mask_len * 4' bytes */
	for (idata = line_index_mask->first; idata; idata = idata->next) {
		txt_undo_store_uint32(utxt->buf, &utxt->pos, idata->value);
	}

	/* Adding number of line numbers to read again.
	 * 4 bytes */
	txt_undo_store_uint32(utxt->buf, &utxt->pos, line_index_mask_len);
	/* Adding current selection.
	 * 12 bytes */
	txt_undo_store_cursors(text, utxt);
	/* Closing with OP (same as above).
	 * 1 byte */
	utxt->buf[utxt->pos] = undo_op;
	/* Marking as last undo operation */
	txt_undo_end(text, utxt);
}

static unsigned short txt_undo_read_uint16(const char *undo_buf, int *undo_pos)
{
	unsigned short val;
	val = undo_buf[*undo_pos]; (*undo_pos)--;
	val = (val << 8) + undo_buf[*undo_pos]; (*undo_pos)--;
	return val;
}

static unsigned int txt_undo_read_uint32(const char *undo_buf, int *undo_pos)
{
	unsigned int val;
	val = undo_buf[*undo_pos]; (*undo_pos)--;
	val = (val << 8) + undo_buf[*undo_pos]; (*undo_pos)--;
	val = (val << 8) + undo_buf[*undo_pos]; (*undo_pos)--;
	val = (val << 8) + undo_buf[*undo_pos]; (*undo_pos)--;
	return val;
}

/* read the cur cursor from the undo buffer */
static void txt_undo_read_cur(const char *undo_buf, int *undo_pos, unsigned int *curln, unsigned short *curc)
{
	*curln = txt_undo_read_uint32(undo_buf, undo_pos);
	*curc  = txt_undo_read_uint16(undo_buf, undo_pos);
}

/* read the sel cursor from the undo buffer */
static void txt_undo_read_sel(const char *undo_buf, int *undo_pos, unsigned int *selln, unsigned short *selc)
{
	*selln = txt_undo_read_uint32(undo_buf, undo_pos);
	*selc  = txt_undo_read_uint16(undo_buf, undo_pos);
}

/* read both cursors from the undo buffer */
static void txt_undo_read_cursors(const char *undo_buf, int *undo_pos,
                                  unsigned int *curln, unsigned short *curc,
                                  unsigned int *selln, unsigned short *selc)
{
	txt_undo_read_sel(undo_buf, undo_pos, selln, selc);
	txt_undo_read_cur(undo_buf, undo_pos, curln, curc);
}

static unsigned int txt_undo_read_unicode(const char *undo_buf, int *undo_pos, short bytes)
{
	unsigned int unicode;
	char utf8[BLI_UTF8_MAX + 1];

	switch (bytes) {
		case 1: /* ascii */
			unicode = undo_buf[*undo_pos]; (*undo_pos)--;
			break;
		case 2: /* 2-byte symbol */
			utf8[2] = '\0';
			utf8[1] = undo_buf[*undo_pos]; (*undo_pos)--;
			utf8[0] = undo_buf[*undo_pos]; (*undo_pos)--;
			unicode = BLI_str_utf8_as_unicode(utf8);
			break;
		case 3: /* 3-byte symbol */
			utf8[3] = '\0';
			utf8[2] = undo_buf[*undo_pos]; (*undo_pos)--;
			utf8[1] = undo_buf[*undo_pos]; (*undo_pos)--;
			utf8[0] = undo_buf[*undo_pos]; (*undo_pos)--;
			unicode = BLI_str_utf8_as_unicode(utf8);
			break;
		case 4: /* 32-bit unicode symbol */
			unicode = txt_undo_read_uint32(undo_buf, undo_pos);
			break;
		default:
			/* should never happen */
			BLI_assert(0);
			unicode = 0;
			break;
	}

	return unicode;
}

static unsigned short txt_redo_read_uint16(const char *undo_buf, int *undo_pos)
{
	unsigned short val;
	val = undo_buf[*undo_pos]; (*undo_pos)++;
	val = val + (undo_buf[*undo_pos] << 8); (*undo_pos)++;
	return val;
}

static unsigned int txt_redo_read_uint32(const char *undo_buf, int *undo_pos)
{
	unsigned int val;
	val = undo_buf[*undo_pos]; (*undo_pos)++;
	val = val + (undo_buf[*undo_pos] << 8); (*undo_pos)++;
	val = val + (undo_buf[*undo_pos] << 16); (*undo_pos)++;
	val = val + (undo_buf[*undo_pos] << 24); (*undo_pos)++;
	return val;
}

/* redo read cur cursor from the undo buffer */
static void txt_redo_read_cur(const char *undo_buf, int *undo_pos, unsigned int *curln, unsigned short *curc)
{
	*curc  = txt_redo_read_uint16(undo_buf, undo_pos);
	*curln = txt_redo_read_uint32(undo_buf, undo_pos);
}

/* redo read sel cursor from the undo buffer */
static void txt_redo_read_sel(const char *undo_buf, int *undo_pos, unsigned int *selln, unsigned short *selc)
{
	*selc  = txt_redo_read_uint16(undo_buf, undo_pos);
	*selln = txt_redo_read_uint32(undo_buf, undo_pos);
}

/* redo read both cursors from the undo buffer */
static void txt_redo_read_cursors(const char *undo_buf, int *undo_pos,
                                  unsigned int *curln, unsigned short *curc,
                                  unsigned int *selln, unsigned short *selc)
{
	txt_redo_read_cur(undo_buf, undo_pos, curln, curc);
	txt_redo_read_sel(undo_buf, undo_pos, selln, selc);
}

static unsigned int txt_redo_read_unicode(const char *undo_buf, int *undo_pos, short bytes)
{
	unsigned int unicode;
	char utf8[BLI_UTF8_MAX + 1];

	switch (bytes) {
		case 1: /* ascii */
			unicode = undo_buf[*undo_pos]; (*undo_pos)++;
			break;
		case 2: /* 2-byte symbol */
			utf8[0] = undo_buf[*undo_pos]; (*undo_pos)++;
			utf8[1] = undo_buf[*undo_pos]; (*undo_pos)++;
			utf8[2] = '\0';
			unicode = BLI_str_utf8_as_unicode(utf8);
			break;
		case 3: /* 3-byte symbol */
			utf8[0] = undo_buf[*undo_pos]; (*undo_pos)++;
			utf8[1] = undo_buf[*undo_pos]; (*undo_pos)++;
			utf8[2] = undo_buf[*undo_pos]; (*undo_pos)++;
			utf8[3] = '\0';
			unicode = BLI_str_utf8_as_unicode(utf8);
			break;
		case 4: /* 32-bit unicode symbol */
			unicode = txt_redo_read_uint32(undo_buf, undo_pos);
			break;
		default:
			/* should never happen */
			BLI_assert(0);
			unicode = 0;
			break;
	}

	return unicode;
}

void txt_do_undo(Text *text, TextUndoBuf *utxt)
{
	int op = utxt->buf[utxt->pos];
	int prev_flags;
	unsigned int linep;
	unsigned int uni_char;
	unsigned int curln, selln;
	unsigned short curc, selc;
	unsigned short charp;
	char *buf;

	if (utxt->pos < 0) {
		return;
	}

	utxt->pos--;

	undoing = 1;

	switch (op) {
		case UNDO_INSERT_1:
		case UNDO_INSERT_2:
		case UNDO_INSERT_3:
		case UNDO_INSERT_4:
			utxt->pos -= op - UNDO_INSERT_1 + 1;

			/* get and restore the cursors */
			txt_undo_read_cur(utxt->buf, &utxt->pos, &curln, &curc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, curln, curc, 1);

			txt_delete_char(text, utxt);

			utxt->pos--;
			break;

		case UNDO_BS_1:
		case UNDO_BS_2:
		case UNDO_BS_3:
		case UNDO_BS_4:
			charp = op - UNDO_BS_1 + 1;
			uni_char = txt_undo_read_unicode(utxt->buf, &utxt->pos, charp);

			/* get and restore the cursors */
			txt_undo_read_cur(utxt->buf, &utxt->pos, &curln, &curc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, curln, curc, 1);

			txt_add_char(text, utxt, uni_char);

			utxt->pos--;
			break;

		case UNDO_DEL_1:
		case UNDO_DEL_2:
		case UNDO_DEL_3:
		case UNDO_DEL_4:
			charp = op - UNDO_DEL_1 + 1;
			uni_char = txt_undo_read_unicode(utxt->buf, &utxt->pos, charp);

			/* get and restore the cursors */
			txt_undo_read_cur(utxt->buf, &utxt->pos, &curln, &curc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, curln, curc, 1);

			txt_add_char(text, utxt, uni_char);

			txt_move_left(text, 0);

			utxt->pos--;
			break;

		case UNDO_DBLOCK:
		{
			int i;
			/* length of the string in the buffer */
			linep = txt_undo_read_uint32(utxt->buf, &utxt->pos);

			buf = MEM_mallocN(linep + 1, "dblock buffer");
			for (i = 0; i < linep; i++) {
				buf[(linep - 1) - i] = utxt->buf[utxt->pos];
				utxt->pos--;
			}
			buf[i] = 0;

			/* skip over the length that was stored again */
			utxt->pos -= 4;

			/* Get the cursor positions */
			txt_undo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);

			/* move cur to location that needs buff inserted */
			txt_move_to(text, curln, curc, 0);

			txt_insert_buf(text, utxt, buf);
			MEM_freeN(buf);

			/* restore the cursors */
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);

			utxt->pos--;

			break;
		}
		case UNDO_IBLOCK:
		{
			int i;
			/* length of the string in the buffer */
			linep = txt_undo_read_uint32(utxt->buf, &utxt->pos);

			/* txt_backspace_char removes utf8-characters, not bytes */
			buf = MEM_mallocN(linep + 1, "iblock buffer");
			for (i = 0; i < linep; i++) {
				buf[(linep - 1) - i] = utxt->buf[utxt->pos];
				utxt->pos--;
			}
			buf[i] = 0;
			linep = BLI_strlen_utf8(buf);
			MEM_freeN(buf);

			/* skip over the length that was stored again */
			utxt->pos -= 4;

			/* get and restore the cursors */
			txt_undo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);

			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);

			if ((curln == selln) && (curc == selc)) {
				/* disable tabs to spaces since moving right may involve skipping multiple spaces */
				prev_flags = text->flags;
				text->flags &= ~TXT_TABSTOSPACES;

				for (i = 0; i < linep; i++)
					txt_move_right(text, 1);

				text->flags = prev_flags;
			}

			txt_delete_selected(text, utxt);

			utxt->pos--;
			break;
		}
		case UNDO_INDENT:
		case UNDO_COMMENT:
		case UNDO_DUPLICATE:
		case UNDO_MOVE_LINES_UP:
		case UNDO_MOVE_LINES_DOWN:
			/* get and restore the cursors */
			txt_undo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);

			if (op == UNDO_INDENT) {
				txt_unindent(text, utxt);
			}
			else if (op == UNDO_COMMENT) {
				txt_uncomment(text, utxt);
			}
			else if (op == UNDO_DUPLICATE) {
				txt_delete_line(text, text->curl->next);
			}
			else if (op == UNDO_MOVE_LINES_UP) {
				txt_move_lines(text, utxt, TXT_MOVE_LINE_DOWN);
			}
			else if (op == UNDO_MOVE_LINES_DOWN) {
				txt_move_lines(text, utxt, TXT_MOVE_LINE_UP);
			}

			utxt->pos--;
			break;
		case UNDO_UNINDENT:
		case UNDO_UNCOMMENT:
		{
			void (*txt_prefix_fn)(Text *, TextUndoBuf *);
			void (*txt_unprefix_fn)(Text *, TextUndoBuf *);
			int count;
			int i;
			/* Get and restore the cursors */
			txt_undo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);

			/* Un-unindent */
			if (op == UNDO_UNINDENT) {
				txt_prefix_fn = txt_indent;
				txt_unprefix_fn = txt_unindent;
			}
			else {
				txt_prefix_fn = txt_comment;
				txt_unprefix_fn = txt_uncomment;
			}

			txt_prefix_fn(text, utxt);

			/* Get the count */
			count = txt_undo_read_uint32(utxt->buf, &utxt->pos);
			/* Iterate! */
			txt_pop_sel(text);

			for (i = 0; i < count; i++) {
				txt_move_to(text, txt_undo_read_uint32(utxt->buf, &utxt->pos), 0, 0);
				/* Un-un-unindent/comment */
				txt_unprefix_fn(text, utxt);
			}
			/* Restore selection */
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);
			/* Jumo over count */
			txt_undo_read_uint32(utxt->buf, &utxt->pos);
			/* Jump over closing OP byte */
			utxt->pos--;
			break;
		}
		default:
			//XXX error("Undo buffer error - resetting");
			utxt->pos = -1;

			break;
	}

	undoing = 0;
}

void txt_do_redo(Text *text, TextUndoBuf *utxt)
{
	char op;
	char *buf;
	unsigned int linep;
	unsigned short charp;
	unsigned int uni_uchar;
	unsigned int curln, selln;
	unsigned short curc, selc;

	utxt->pos++;
	op = utxt->buf[utxt->pos];

	if (!op) {
		utxt->pos--;
		return;
	}

	undoing = 1;

	switch (op) {
		case UNDO_INSERT_1:
		case UNDO_INSERT_2:
		case UNDO_INSERT_3:
		case UNDO_INSERT_4:
			utxt->pos++;

			/* get and restore the cursors */
			txt_redo_read_cur(utxt->buf, &utxt->pos, &curln, &curc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, curln, curc, 1);

			charp = op - UNDO_INSERT_1 + 1;
			uni_uchar = txt_redo_read_unicode(utxt->buf, &utxt->pos, charp);

			txt_add_char(text, utxt, uni_uchar);
			break;

		case UNDO_BS_1:
		case UNDO_BS_2:
		case UNDO_BS_3:
		case UNDO_BS_4:
			utxt->pos++;

			/* get and restore the cursors */
			txt_redo_read_cur(utxt->buf, &utxt->pos, &curln, &curc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, curln, curc, 1);

			utxt->pos += op - UNDO_BS_1 + 1;

			/* move right so we backspace the correct char */
			txt_move_right(text, 0);
			txt_backspace_char(text, utxt);

			break;

		case UNDO_DEL_1:
		case UNDO_DEL_2:
		case UNDO_DEL_3:
		case UNDO_DEL_4:
			utxt->pos++;

			/* get and restore the cursors */
			txt_redo_read_cur(utxt->buf, &utxt->pos, &curln, &curc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, curln, curc, 1);

			utxt->pos += op - UNDO_DEL_1 + 1;

			txt_delete_char(text, utxt);

			break;

		case UNDO_DBLOCK:
			utxt->pos++;

			/* get and restore the cursors */
			txt_redo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);

			/* length of the block */
			linep = txt_redo_read_uint32(utxt->buf, &utxt->pos);

			utxt->pos += linep;

			/* skip over the length that was stored again */
			utxt->pos += 4;

			txt_delete_sel(text, utxt);

			break;

		case UNDO_IBLOCK:
			utxt->pos++;

			/* get and restore the cursors */
			txt_redo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, curln, curc, 1);

			/* length of the block */
			linep = txt_redo_read_uint32(utxt->buf, &utxt->pos);

			buf = MEM_mallocN(linep + 1, "iblock buffer");
			memcpy(buf, &utxt->buf[utxt->pos], linep);
			utxt->pos += linep;
			buf[linep] = 0;

			txt_insert_buf(text, utxt, buf);
			MEM_freeN(buf);

			/* skip over the length that was stored again */
			utxt->pos += 4;

			break;

		case UNDO_INDENT:
		case UNDO_COMMENT:
		case UNDO_UNCOMMENT:
		case UNDO_DUPLICATE:
		case UNDO_MOVE_LINES_UP:
		case UNDO_MOVE_LINES_DOWN:
			utxt->pos++;

			/* get and restore the cursors */
			txt_redo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);

			if (op == UNDO_INDENT) {
				txt_indent(text, utxt);
			}
			else if (op == UNDO_COMMENT) {
				txt_comment(text, utxt);
			}
			else if (op == UNDO_UNCOMMENT) {
				txt_uncomment(text, utxt);
			}
			else if (op == UNDO_DUPLICATE) {
				txt_duplicate_line(text, utxt);
			}
			else if (op == UNDO_MOVE_LINES_UP) {
				/* offset the cursor by + 1 */
				txt_move_to(text, curln + 1, curc, 0);
				txt_move_to(text, selln + 1, selc, 1);

				txt_move_lines(text, utxt, TXT_MOVE_LINE_UP);
			}
			else if (op == UNDO_MOVE_LINES_DOWN) {
				/* offset the cursor by - 1 */
				txt_move_to(text, curln - 1, curc, 0);
				txt_move_to(text, selln - 1, selc, 1);

				txt_move_lines(text, utxt, TXT_MOVE_LINE_DOWN);
			}

			/* re-restore the cursors since they got moved when redoing */
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);

			break;
		case UNDO_UNINDENT:
		{
			int count;
			int i;

			utxt->pos++;
			/* Scan all the stuff described in txt_undo_add_unindent_op */
			count = txt_redo_read_uint32(utxt->buf, &utxt->pos);
			for (i = 0; i < count; i++) {
				txt_redo_read_uint32(utxt->buf, &utxt->pos);
			}
			/* Count again */
			txt_redo_read_uint32(utxt->buf, &utxt->pos);
			/* Get the selection and re-unindent */
			txt_redo_read_cursors(utxt->buf, &utxt->pos, &curln, &curc, &selln, &selc);
			txt_move_to(text, curln, curc, 0);
			txt_move_to(text, selln, selc, 1);
			txt_unindent(text, utxt);
			break;
		}
		default:
			//XXX error("Undo buffer error - resetting");
			utxt->pos = -1;

			break;
	}

	undoing = 0;
}

/**************************/
/* Line editing functions */
/**************************/

void txt_split_curline(Text *text, TextUndoBuf *utxt)
{
	TextLine *ins;
	char *left, *right;

	if (!text->curl) return;

	txt_delete_sel(text, utxt);

	if (!undoing) txt_undo_add_charop(text, utxt, UNDO_INSERT_1, '\n');

	/* Make the two half strings */

	left = MEM_mallocN(text->curc + 1, "textline_string");
	if (text->curc) memcpy(left, text->curl->line, text->curc);
	left[text->curc] = 0;

	right = MEM_mallocN(text->curl->len - text->curc + 1, "textline_string");
	memcpy(right, text->curl->line + text->curc, text->curl->len - text->curc + 1);

	MEM_freeN(text->curl->line);
	if (text->curl->format) MEM_freeN(text->curl->format);

	/* Make the new TextLine */

	ins = MEM_mallocN(sizeof(TextLine), "textline");
	ins->line = left;
	ins->format = NULL;
	ins->len = text->curc;

	text->curl->line = right;
	text->curl->format = NULL;
	text->curl->len = text->curl->len - text->curc;

	BLI_insertlinkbefore(&text->lines, text->curl, ins);

	text->curc = 0;

	txt_make_dirty(text);
	txt_clean_text(text);

	txt_pop_sel(text);
}

static void txt_delete_line(Text *text, TextLine *line)
{
	if (!text->curl) return;

	BLI_remlink(&text->lines, line);

	if (line->line) MEM_freeN(line->line);
	if (line->format) MEM_freeN(line->format);

	MEM_freeN(line);

	txt_make_dirty(text);
	txt_clean_text(text);
}

static void txt_combine_lines(Text *text, TextLine *linea, TextLine *lineb)
{
	char *tmp, *s;

	if (!linea || !lineb) return;


	tmp = MEM_mallocN(linea->len + lineb->len + 1, "textline_string");

	s = tmp;
	s += BLI_strcpy_rlen(s, linea->line);
	s += BLI_strcpy_rlen(s, lineb->line);
	(void)s;

	make_new_line(linea, tmp);

	txt_delete_line(text, lineb);

	txt_make_dirty(text);
	txt_clean_text(text);
}

void txt_duplicate_line(Text *text, TextUndoBuf *utxt)
{
	TextLine *textline;

	if (!text->curl) return;

	if (text->curl == text->sell) {
		textline = txt_new_line(text->curl->line);
		BLI_insertlinkafter(&text->lines, text->curl, textline);

		txt_make_dirty(text);
		txt_clean_text(text);

		if (!undoing) txt_undo_add_op(text, utxt, UNDO_DUPLICATE);
	}
}

void txt_delete_char(Text *text, TextUndoBuf *utxt)
{
	unsigned int c = '\n';

	if (!text->curl) return;

	if (txt_has_sel(text)) { /* deleting a selection */
		txt_delete_sel(text, utxt);
		txt_make_dirty(text);
		return;
	}
	else if (text->curc == text->curl->len) { /* Appending two lines */
		if (text->curl->next) {
			txt_combine_lines(text, text->curl, text->curl->next);
			txt_pop_sel(text);
		}
		else
			return;
	}
	else { /* Just deleting a char */
		size_t c_len = 0;
		c = BLI_str_utf8_as_unicode_and_size(text->curl->line + text->curc, &c_len);

		memmove(text->curl->line + text->curc, text->curl->line + text->curc + c_len, text->curl->len - text->curc - c_len + 1);

		text->curl->len -= c_len;

		txt_pop_sel(text);
	}

	txt_make_dirty(text);
	txt_clean_text(text);

	if (!undoing) txt_undo_add_charop(text, utxt, UNDO_DEL_1, c);
}

void txt_delete_word(Text *text, TextUndoBuf *utxt)
{
	txt_jump_right(text, true, true);
	txt_delete_sel(text, utxt);
	txt_make_dirty(text);
}

void txt_backspace_char(Text *text, TextUndoBuf *utxt)
{
	unsigned int c = '\n';

	if (!text->curl) return;

	if (txt_has_sel(text)) { /* deleting a selection */
		txt_delete_sel(text, utxt);
		txt_make_dirty(text);
		return;
	}
	else if (text->curc == 0) { /* Appending two lines */
		if (!text->curl->prev) return;

		text->curl = text->curl->prev;
		text->curc = text->curl->len;

		txt_combine_lines(text, text->curl, text->curl->next);
		txt_pop_sel(text);
	}
	else { /* Just backspacing a char */
		size_t c_len = 0;
		const char *prev = BLI_str_prev_char_utf8(text->curl->line + text->curc);
		c = BLI_str_utf8_as_unicode_and_size(prev, &c_len);

		/* source and destination overlap, don't use memcpy() */
		memmove(text->curl->line + text->curc - c_len,
		        text->curl->line + text->curc,
		        text->curl->len  - text->curc + 1);

		text->curl->len -= c_len;
		text->curc -= c_len;

		txt_pop_sel(text);
	}

	txt_make_dirty(text);
	txt_clean_text(text);

	if (!undoing) txt_undo_add_charop(text, utxt, UNDO_BS_1, c);
}

void txt_backspace_word(Text *text, TextUndoBuf *utxt)
{
	txt_jump_left(text, true, true);
	txt_delete_sel(text, utxt);
	txt_make_dirty(text);
}

/* Max spaces to replace a tab with, currently hardcoded to TXT_TABSIZE = 4.
 * Used by txt_convert_tab_to_spaces, indent and unindent.
 * Remember to change this string according to max tab size */
static char tab_to_spaces[] = "    ";

static void txt_convert_tab_to_spaces(Text *text, TextUndoBuf *utxt)
{
	/* sb aims to pad adjust the tab-width needed so that the right number of spaces
	 * is added so that the indention of the line is the right width (i.e. aligned
	 * to multiples of TXT_TABSIZE)
	 */
	const char *sb = &tab_to_spaces[text->curc % TXT_TABSIZE];
	txt_insert_buf(text, utxt, sb);
}

static bool txt_add_char_intern(Text *text, TextUndoBuf *utxt, unsigned int add, bool replace_tabs)
{
	char *tmp, ch[BLI_UTF8_MAX];
	size_t add_len;

	if (!text->curl) return 0;

	if (add == '\n') {
		txt_split_curline(text, utxt);
		return true;
	}

	/* insert spaces rather than tabs */
	if (add == '\t' && replace_tabs) {
		txt_convert_tab_to_spaces(text, utxt);
		return true;
	}

	txt_delete_sel(text, utxt);

	if (!undoing) txt_undo_add_charop(text, utxt, UNDO_INSERT_1, add);

	add_len = BLI_str_utf8_from_unicode(add, ch);

	tmp = MEM_mallocN(text->curl->len + add_len + 1, "textline_string");

	memcpy(tmp, text->curl->line, text->curc);
	memcpy(tmp + text->curc, ch, add_len);
	memcpy(tmp + text->curc + add_len, text->curl->line + text->curc, text->curl->len - text->curc + 1);

	make_new_line(text->curl, tmp);

	text->curc += add_len;

	txt_pop_sel(text);

	txt_make_dirty(text);
	txt_clean_text(text);

	return 1;
}

bool txt_add_char(Text *text, TextUndoBuf *utxt, unsigned int add)
{
	return txt_add_char_intern(text, utxt, add, (text->flags & TXT_TABSTOSPACES) != 0);
}

bool txt_add_raw_char(Text *text, TextUndoBuf *utxt, unsigned int add)
{
	return txt_add_char_intern(text, utxt, add, 0);
}

void txt_delete_selected(Text *text, TextUndoBuf *utxt)
{
	txt_delete_sel(text, utxt);
	txt_make_dirty(text);
}

bool txt_replace_char(Text *text, TextUndoBuf *utxt, unsigned int add)
{
	unsigned int del;
	size_t del_size = 0, add_size;
	char ch[BLI_UTF8_MAX];

	if (!text->curl) return false;

	/* If text is selected or we're at the end of the line just use txt_add_char */
	if (text->curc == text->curl->len || txt_has_sel(text) || add == '\n') {
		return txt_add_char(text, utxt, add);
	}

	del = BLI_str_utf8_as_unicode_and_size(text->curl->line + text->curc, &del_size);
	add_size = BLI_str_utf8_from_unicode(add, ch);

	if (add_size > del_size) {
		char *tmp = MEM_mallocN(text->curl->len + add_size - del_size + 1, "textline_string");
		memcpy(tmp, text->curl->line, text->curc);
		memcpy(tmp + text->curc + add_size, text->curl->line + text->curc + del_size, text->curl->len - text->curc - del_size + 1);
		MEM_freeN(text->curl->line);
		text->curl->line = tmp;
	}
	else if (add_size < del_size) {
		char *tmp = text->curl->line;
		memmove(tmp + text->curc + add_size, tmp + text->curc + del_size, text->curl->len - text->curc - del_size + 1);
	}

	memcpy(text->curl->line + text->curc, ch, add_size);
	text->curc += add_size;
	text->curl->len += add_size - del_size;

	txt_pop_sel(text);
	txt_make_dirty(text);
	txt_clean_text(text);

	/* Should probably create a new op for this */
	if (!undoing) {
		txt_undo_add_charop(text, utxt, UNDO_INSERT_1, add);
		text->curc -= add_size;
		txt_pop_sel(text);
		txt_undo_add_charop(text, utxt, UNDO_DEL_1, del);
		text->curc += add_size;
		txt_pop_sel(text);
	}
	return true;
}

/**
 * Generic prefix operation, use for comment & indent.
 *
 * \note caller must handle undo.
 */
static void txt_select_prefix(Text *text, const char *add)
{
	int len, num, curc_old;
	char *tmp;

	const int indentlen = strlen(add);

	BLI_assert(!ELEM(NULL, text->curl, text->sell));

	curc_old = text->curc;

	num = 0;
	while (true) {

		/* don't indent blank lines */
		if (text->curl->len != 0) {
			tmp = MEM_mallocN(text->curl->len + indentlen + 1, "textline_string");

			text->curc = 0;
			if (text->curc) memcpy(tmp, text->curl->line, text->curc);  /* XXX never true, check prev line */
			memcpy(tmp + text->curc, add, indentlen);

			len = text->curl->len - text->curc;
			if (len > 0) memcpy(tmp + text->curc + indentlen, text->curl->line + text->curc, len);
			tmp[text->curl->len + indentlen] = 0;

			make_new_line(text->curl, tmp);

			text->curc += indentlen;

			txt_make_dirty(text);
			txt_clean_text(text);
		}

		if (text->curl == text->sell) {
			text->selc += indentlen;
			break;
		}
		else {
			text->curl = text->curl->next;
			num++;
		}
	}
	if (!curc_old) text->curc = 0;
	else text->curc = curc_old + indentlen;

	while (num > 0) {
		text->curl = text->curl->prev;
		num--;
	}

	/* caller must handle undo */
}

/**
 * Generic un-prefix operation, use for comment & indent.
 *
 * \param r_line_index_mask: List of lines that are already at indent level 0,
 * to store them later into the undo buffer.
 *
 * \note caller must handle undo.
 */
static void txt_select_unprefix(
        Text *text, const char *remove,
        ListBase *r_line_index_mask, int *r_line_index_mask_len)
{
	int num = 0;
	const int indentlen = strlen(remove);
	bool unindented_first = false;

	int curl_span_init = 0;

	BLI_assert(!ELEM(NULL, text->curl, text->sell));

	BLI_listbase_clear(r_line_index_mask);
	*r_line_index_mask_len = 0;

	if (!undoing) {
		curl_span_init = txt_get_span(text->lines.first, text->curl);
	}

	while (true) {
		bool changed = false;
		if (STREQLEN(text->curl->line, remove, indentlen)) {
			if (num == 0)
				unindented_first = true;
			text->curl->len -= indentlen;
			memmove(text->curl->line, text->curl->line + indentlen, text->curl->len + 1);
			changed = true;
		}
		else {
			if (!undoing) {
				/* Create list element for 0 indent line */
				struct LinkInt *idata = MEM_mallocN(sizeof(struct LinkInt), __func__);
				idata->value = curl_span_init + num;
				BLI_assert(idata->value == txt_get_span(text->lines.first, text->curl));
				BLI_addtail(r_line_index_mask, idata);
				(*r_line_index_mask_len) += 1;
			}
		}

		txt_make_dirty(text);
		txt_clean_text(text);

		if (text->curl == text->sell) {
			if (changed)
				text->selc = MAX2(text->selc - indentlen, 0);
			break;
		}
		else {
			text->curl = text->curl->next;
			num++;

		}

	}

	if (unindented_first)
		text->curc = MAX2(text->curc - indentlen, 0);

	while (num > 0) {
		text->curl = text->curl->prev;
		num--;
	}

	/* caller must handle undo */
}

void txt_comment(Text *text, TextUndoBuf *utxt)
{
	const char *prefix = "#";

	if (ELEM(NULL, text->curl, text->sell)) {
		return;
	}

	txt_select_prefix(text, prefix);

	if (!undoing) {
		txt_undo_add_op(text, utxt, UNDO_COMMENT);
	}
}

void txt_uncomment(Text *text, TextUndoBuf *utxt)
{
	const char *prefix = "#";
	ListBase line_index_mask;
	int line_index_mask_len;

	if (ELEM(NULL, text->curl, text->sell)) {
		return;
	}

	txt_select_unprefix(text, prefix, &line_index_mask, &line_index_mask_len);

	if (!undoing) {
		txt_undo_add_unprefix_op(text, utxt, UNDO_UNCOMMENT, &line_index_mask, line_index_mask_len);
	}

	BLI_freelistN(&line_index_mask);
}

void txt_indent(Text *text, TextUndoBuf *utxt)
{
	const char *prefix = (text->flags & TXT_TABSTOSPACES) ? tab_to_spaces : "\t";

	if (ELEM(NULL, text->curl, text->sell)) {
		return;
	}

	txt_select_prefix(text, prefix);

	if (!undoing) {
		txt_undo_add_op(text, utxt, UNDO_INDENT);
	}
}

void txt_unindent(Text *text, TextUndoBuf *utxt)
{
	const char *prefix = (text->flags & TXT_TABSTOSPACES) ? tab_to_spaces : "\t";
	ListBase line_index_mask;
	int line_index_mask_len;

	if (ELEM(NULL, text->curl, text->sell)) {
		return;
	}

	txt_select_unprefix(text, prefix, &line_index_mask, &line_index_mask_len);

	if (!undoing) {
		txt_undo_add_unprefix_op(text, utxt, UNDO_UNINDENT, &line_index_mask, line_index_mask_len);
	}

	BLI_freelistN(&line_index_mask);
}

void txt_move_lines(struct Text *text, TextUndoBuf *utxt, const int direction)
{
	TextLine *line_other;

	BLI_assert(ELEM(direction, TXT_MOVE_LINE_UP, TXT_MOVE_LINE_DOWN));

	if (!text->curl || !text->sell) return;

	txt_order_cursors(text, false);

	line_other =  (direction == TXT_MOVE_LINE_DOWN) ? text->sell->next : text->curl->prev;

	if (!line_other) return;

	BLI_remlink(&text->lines, line_other);

	if (direction == TXT_MOVE_LINE_DOWN) {
		BLI_insertlinkbefore(&text->lines, text->curl, line_other);
	}
	else {
		BLI_insertlinkafter(&text->lines, text->sell, line_other);
	}

	txt_make_dirty(text);
	txt_clean_text(text);

	if (!undoing) {
		txt_undo_add_op(text, utxt, (direction == TXT_MOVE_LINE_DOWN) ? UNDO_MOVE_LINES_DOWN : UNDO_MOVE_LINES_UP);
	}
}

int txt_setcurr_tab_spaces(Text *text, int space)
{
	int i = 0;
	int test = 0;
	const char *word = ":";
	const char *comm = "#";
	const char indent = (text->flags & TXT_TABSTOSPACES) ? ' ' : '\t';
	static const char *back_words[] = {"return", "break", "continue", "pass", "yield", NULL};

	if (!text->curl) return 0;

	while (text->curl->line[i] == indent) {
		//we only count those tabs/spaces that are before any text or before the curs;
		if (i == text->curc) {
			return i;
		}
		else {
			i++;
		}
	}
	if (strstr(text->curl->line, word)) {
		/* if we find a ':' on this line, then add a tab but not if it is:
		 * 1) in a comment
		 * 2) within an identifier
		 * 3) after the cursor (text->curc), i.e. when creating space before a function def [#25414]
		 */
		int a;
		bool is_indent = false;
		for (a = 0; (a < text->curc) && (text->curl->line[a] != '\0'); a++) {
			char ch = text->curl->line[a];
			if (ch == '#') {
				break;
			}
			else if (ch == ':') {
				is_indent = 1;
			}
			else if (ch != ' ' && ch != '\t') {
				is_indent = 0;
			}
		}
		if (is_indent) {
			i += space;
		}
	}

	for (test = 0; back_words[test]; test++) {
		/* if there are these key words then remove a tab because we are done with the block */
		if (strstr(text->curl->line, back_words[test]) && i > 0) {
			if (strcspn(text->curl->line, back_words[test]) < strcspn(text->curl->line, comm)) {
				i -= space;
			}
		}
	}
	return i;
}

/*******************************/
/* Character utility functions */
/*******************************/

int text_check_bracket(const char ch)
{
	int a;
	char opens[] = "([{";
	char close[] = ")]}";

	for (a = 0; a < (sizeof(opens) - 1); a++) {
		if (ch == opens[a])
			return a + 1;
		else if (ch == close[a])
			return -(a + 1);
	}
	return 0;
}

/* TODO, have a function for operators - http://docs.python.org/py3k/reference/lexical_analysis.html#operators */
bool text_check_delim(const char ch)
{
	int a;
	char delims[] = "():\"\' ~!%^&*-+=[]{};/<>|.#\t,@";

	for (a = 0; a < (sizeof(delims) - 1); a++) {
		if (ch == delims[a])
			return true;
	}
	return false;
}

bool text_check_digit(const char ch)
{
	if (ch < '0') return false;
	if (ch <= '9') return true;
	return false;
}

bool text_check_identifier(const char ch)
{
	if (ch < '0') return false;
	if (ch <= '9') return true;
	if (ch < 'A') return false;
	if (ch <= 'Z' || ch == '_') return true;
	if (ch < 'a') return false;
	if (ch <= 'z') return true;
	return false;
}

bool text_check_identifier_nodigit(const char ch)
{
	if (ch <= '9') return false;
	if (ch < 'A') return false;
	if (ch <= 'Z' || ch == '_') return true;
	if (ch < 'a') return false;
	if (ch <= 'z') return true;
	return false;
}

#ifndef WITH_PYTHON
int text_check_identifier_unicode(const unsigned int ch)
{
	return (ch < 255 && text_check_identifier((unsigned int)ch));
}

int text_check_identifier_nodigit_unicode(const unsigned int ch)
{
	return (ch < 255 && text_check_identifier_nodigit((char)ch));
}
#endif  /* WITH_PYTHON */

bool text_check_whitespace(const char ch)
{
	if (ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n')
		return true;
	return false;
}

int text_find_identifier_start(const char *str, int i)
{
	if (UNLIKELY(i <= 0)) {
		return 0;
	}

	while (i--) {
		if (!text_check_identifier(str[i])) {
			break;
		}
	}
	i++;
	return i;
}