/* $OpenBSD: screen.c,v 1.107 2026/07/26 09:20:54 nicm Exp $ */

/*
 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <vis.h>

#include "tmux.h"

/* Selected area in screen. */
struct screen_sel {
        int              hidden;
        int              rectangle;
        int              modekeys;

        u_int            sx;
        u_int            sy;

        u_int            ex;
        u_int            ey;

        u_int            clipx;

        struct grid_cell cell;
};

/* Entry on title stack. */
struct screen_title_entry {
        char                            *text;

        TAILQ_ENTRY(screen_title_entry)  entry;
};
TAILQ_HEAD(screen_titles, screen_title_entry);

static void     screen_resize_y(struct screen *, u_int, int, u_int *);
static void     screen_reflow(struct screen *, u_int, u_int *, u_int *, int);

/* Free titles stack. */
static void
screen_free_titles(struct screen *s)
{
        struct screen_title_entry       *title_entry;

        if (s->titles == NULL)
                return;

        while ((title_entry = TAILQ_FIRST(s->titles)) != NULL) {
                TAILQ_REMOVE(s->titles, title_entry, entry);
                free(title_entry->text);
                free(title_entry);
        }

        free(s->titles);
        s->titles = NULL;
        s->ntitles = 0;
}

/* Create a new screen. */
void
screen_init(struct screen *s, u_int sx, u_int sy, u_int hlimit)
{
        s->grid = grid_create(sx, sy, hlimit);
        s->saved_grid = NULL;

        s->title = xstrdup("");
        s->titles = NULL;
        s->ntitles = 0;
        s->path = NULL;

        s->cstyle = SCREEN_CURSOR_DEFAULT;
        s->default_cstyle = SCREEN_CURSOR_DEFAULT;
        s->mode = MODE_CURSOR;
        s->default_mode = 0;
        s->ccolour = -1;
        s->default_ccolour = -1;
        s->tabs = NULL;
        s->sel = NULL;

        s->write_list = NULL;
        s->hyperlinks = NULL;

        screen_reinit(s);
}

/* Reinitialise screen. */
void
screen_reinit(struct screen *s)
{
        s->cx = 0;
        s->cy = 0;

        s->rupper = 0;
        s->rlower = screen_size_y(s) - 1;

        s->mode = MODE_CURSOR|MODE_WRAP|(s->mode & MODE_CRLF);

        if (options_get_number(global_options, "extended-keys") == 2)
                s->mode = (s->mode & ~EXTENDED_KEY_MODES)|MODE_KEYS_EXTENDED;

        if (SCREEN_IS_ALTERNATE(s))
                screen_alternate_off(s, NULL, 0);
        s->saved_cx = UINT_MAX;
        s->saved_cy = UINT_MAX;

        screen_reset_tabs(s);

        grid_clear_lines(s->grid, s->grid->hsize, s->grid->sy, 8);

        screen_clear_selection(s);
        screen_free_titles(s);
        screen_set_progress_bar(s, PROGRESS_BAR_HIDDEN, 0);
        screen_reset_hyperlinks(s);
}

/* Reset hyperlinks of a screen. */
void
screen_reset_hyperlinks(struct screen *s)
{
        if (s->hyperlinks == NULL)
                s->hyperlinks = hyperlinks_init();
        else
                hyperlinks_reset(s->hyperlinks);
}

/* Destroy a screen. */
void
screen_free(struct screen *s)
{
        free(s->sel);
        free(s->tabs);
        free(s->path);
        free(s->title);

        if (s->write_list != NULL)
                screen_write_free_list(s);

        if (SCREEN_IS_ALTERNATE(s))
                grid_destroy(s->saved_grid);
        grid_destroy(s->grid);

        if (s->hyperlinks != NULL)
                hyperlinks_free(s->hyperlinks);
        screen_free_titles(s);
}

/* Reset tabs to default, eight spaces apart. */
void
screen_reset_tabs(struct screen *s)
{
        u_int   i;

        free(s->tabs);

        if ((s->tabs = bit_alloc(screen_size_x(s))) == NULL)
                fatal("bit_alloc failed");
        for (i = 8; i < screen_size_x(s); i += 8)
                bit_set(s->tabs, i);
}

/* Set default cursor style and colour from options. */
void
screen_set_default_cursor(struct screen *s, struct options *oo)
{
        struct grid_cell        gc;
        int                     c;

        style_apply(&gc, oo, "cursor-colour", NULL);
        s->default_ccolour = gc.fg;

        c = options_get_number(oo, "cursor-style");
        s->default_mode = 0;
        screen_set_cursor_style(c, &s->default_cstyle, &s->default_mode);
}

/* Set screen cursor style and mode. */
void
screen_set_cursor_style(u_int style, enum screen_cursor_style *cstyle,
    int *mode)
{
        switch (style) {
        case 0:
                *cstyle = SCREEN_CURSOR_DEFAULT;
                break;
        case 1:
                *cstyle = SCREEN_CURSOR_BLOCK;
                *mode |= MODE_CURSOR_BLINKING;
                break;
        case 2:
                *cstyle = SCREEN_CURSOR_BLOCK;
                *mode &= ~MODE_CURSOR_BLINKING;
                break;
        case 3:
                *cstyle = SCREEN_CURSOR_UNDERLINE;
                *mode |= MODE_CURSOR_BLINKING;
                break;
        case 4:
                *cstyle = SCREEN_CURSOR_UNDERLINE;
                *mode &= ~MODE_CURSOR_BLINKING;
                break;
        case 5:
                *cstyle = SCREEN_CURSOR_BAR;
                *mode |= MODE_CURSOR_BLINKING;
                break;
        case 6:
                *cstyle = SCREEN_CURSOR_BAR;
                *mode &= ~MODE_CURSOR_BLINKING;
                break;
        }
}

/* Set screen cursor colour. */
void
screen_set_cursor_colour(struct screen *s, int colour)
{
        s->ccolour = colour;
}

/* Set screen title. */
int
screen_set_title(struct screen *s, const char *title, int untrusted)
{
        char    *new_title;

        new_title = clean_name(title, untrusted);
        if (new_title == NULL)
                return (0);
        free(s->title);
        s->title = new_title;
        return (1);
}

/* Set screen path. */
int
screen_set_path(struct screen *s, const char *path, int untrusted)
{
        char    *new_path;

        new_path = clean_name(path, untrusted);
        if (new_path == NULL)
                return (0);
        free(s->path);
        s->path = new_path;
        return (1);
}

/* Push the current title onto the stack. */
void
screen_push_title(struct screen *s)
{
        struct screen_title_entry *title_entry;

        log_debug("%s: %u", __func__, s->ntitles);

        while (s->ntitles >= 10) {
                title_entry = TAILQ_LAST(s->titles, screen_titles);
                free(title_entry->text);
                TAILQ_REMOVE(s->titles, title_entry, entry);
                free(title_entry);
                s->ntitles--;
        }

        if (s->titles == NULL) {
                s->titles = xmalloc(sizeof *s->titles);
                TAILQ_INIT(s->titles);
        }
        title_entry = xmalloc(sizeof *title_entry);
        title_entry->text = xstrdup(s->title);
        TAILQ_INSERT_HEAD(s->titles, title_entry, entry);
        s->ntitles++;
}

/*
 * Pop a title from the stack and set it as the screen title. If the stack is
 * empty, do nothing.
 */
void
screen_pop_title(struct screen *s)
{
        struct screen_title_entry *title_entry;

        if (s->titles == NULL)
                return;
        log_debug("%s: %u", __func__, s->ntitles);

        title_entry = TAILQ_FIRST(s->titles);
        if (title_entry != NULL) {
                free(s->title);
                s->title = title_entry->text;
                TAILQ_REMOVE(s->titles, title_entry, entry);
                free(title_entry);
                s->ntitles--;
        }
}

/*
 * Set the progress bar state and progress. The progress will not be updated
 * if p is negative.
 */
void
screen_set_progress_bar(struct screen *s, enum progress_bar_state pbs, int p)
{
        s->progress_bar.state = pbs;
        if (p >= 0 && pbs != PROGRESS_BAR_INDETERMINATE)
                s->progress_bar.progress = p;
}


/* Resize screen with options. */
void
screen_resize_cursor(struct screen *s, u_int sx, u_int sy, int reflow,
    int eat_empty, int cursor)
{
        u_int   cx = s->cx, cy = s->grid->hsize + s->cy;

        if (s->write_list != NULL)
                screen_write_free_list(s);

        log_debug("%s: new size %ux%u, now %ux%u (cursor %u,%u = %u,%u)",
            __func__, sx, sy, screen_size_x(s), screen_size_y(s), s->cx, s->cy,
            cx, cy);

        if (sx < 1)
                sx = 1;
        if (sy < 1)
                sy = 1;

        if (sx != screen_size_x(s)) {
                s->grid->sx = sx;
                screen_reset_tabs(s);
        } else
                reflow = 0;

        if (sy != screen_size_y(s))
                screen_resize_y(s, sy, eat_empty, &cy);

        if (reflow)
                screen_reflow(s, sx, &cx, &cy, cursor);

        if (cy >= s->grid->hsize) {
                s->cx = cx;
                s->cy = cy - s->grid->hsize;
        } else {
                s->cx = 0;
                s->cy = 0;
        }

        log_debug("%s: cursor finished at %u,%u = %u,%u", __func__, s->cx,
            s->cy, cx, cy);

        if (s->write_list != NULL)
                screen_write_make_list(s);
}

/* Resize screen. */
void
screen_resize(struct screen *s, u_int sx, u_int sy, int reflow)
{
        screen_resize_cursor(s, sx, sy, reflow, 1, 1);
}

static void
screen_resize_y(struct screen *s, u_int sy, int eat_empty, u_int *cy)
{
        struct grid     *gd = s->grid;
        u_int            needed, available, oldy, i;

        if (sy == 0)
                fatalx("zero size");
        oldy = screen_size_y(s);

        /*
         * When resizing:
         *
         * If the height is decreasing, delete lines from the bottom until
         * hitting the cursor, then push lines from the top into the history.
         *
         * When increasing, pull as many lines as possible from scrolled
         * history (not explicitly cleared from view) to the top, then fill the
         * remaining with blanks at the bottom.
         */

        /* Size decreasing. */
        if (sy < oldy) {
                needed = oldy - sy;

                /* Delete as many lines as possible from the bottom. */
                if (eat_empty) {
                        available = oldy - 1 - s->cy;
                        if (available > 0) {
                                if (available > needed)
                                        available = needed;
                                grid_view_delete_lines(gd, oldy - available,
                                    available, 8);
                        }
                        needed -= available;
                }

                /*
                 * Now just increase the history size, if possible, to take
                 * over the lines which are left. If history is off, delete
                 * lines from the top.
                 */
                available = s->cy;
                if (gd->flags & GRID_HISTORY) {
                        gd->hscrolled += needed;
                        gd->hsize += needed;
                } else if (needed > 0 && available > 0) {
                        if (available > needed)
                                available = needed;
                        grid_view_delete_lines(gd, 0, available, 8);
                        (*cy) -= available;
                }
        }

        /* Resize line array. */
        grid_adjust_lines(gd, gd->hsize + sy);

        /* Size increasing. */
        if (sy > oldy) {
                needed = sy - oldy;

                /*
                 * Try to pull as much as possible out of scrolled history, if
                 * it is enabled.
                 */
                available = gd->hscrolled;
                if (gd->flags & GRID_HISTORY && available > 0) {
                        if (available > needed)
                                available = needed;
                        gd->hscrolled -= available;
                        gd->hsize -= available;
                } else
                        available = 0;
                needed -= available;

                /* Then fill the rest in with blanks. */
                for (i = gd->hsize + sy - needed; i < gd->hsize + sy; i++)
                        grid_empty_line(gd, i, 8);
        }

        /* Set the new size, and reset the scroll region. */
        gd->sy = sy;
        s->rupper = 0;
        s->rlower = screen_size_y(s) - 1;
}

/* Set selection. */
void
screen_set_selection(struct screen *s, u_int sx, u_int sy,
    u_int ex, u_int ey, u_int rectangle, u_int clipx, int modekeys,
    struct grid_cell *gc)
{
        if (s->sel == NULL)
                s->sel = xcalloc(1, sizeof *s->sel);

        memcpy(&s->sel->cell, gc, sizeof s->sel->cell);
        s->sel->hidden = 0;
        s->sel->rectangle = rectangle;
        s->sel->modekeys = modekeys;

        s->sel->sx = sx;
        s->sel->sy = sy;
        s->sel->ex = ex;
        s->sel->ey = ey;
        s->sel->clipx = clipx;
}

/* Clear selection. */
void
screen_clear_selection(struct screen *s)
{
        free(s->sel);
        s->sel = NULL;
}

/* Hide selection. */
void
screen_hide_selection(struct screen *s)
{
        if (s->sel != NULL)
                s->sel->hidden = 1;
}

/* Check if cell in selection. */
int
screen_check_selection(struct screen *s, u_int px, u_int py)
{
        struct screen_sel       *sel = s->sel;
        u_int                    xx;

        if (sel == NULL || sel->hidden)
                return (0);
        if (px < sel->clipx)
                return (0);

        if (sel->rectangle) {
                if (sel->sy < sel->ey) {
                        /* start line < end line -- downward selection. */
                        if (py < sel->sy || py > sel->ey)
                                return (0);
                } else if (sel->sy > sel->ey) {
                        /* start line > end line -- upward selection. */
                        if (py > sel->sy || py < sel->ey)
                                return (0);
                } else {
                        /* starting line == ending line. */
                        if (py != sel->sy)
                                return (0);
                }

                /*
                 * Need to include the selection start row, but not the cursor
                 * row, which means the selection changes depending on which
                 * one is on the left.
                 */
                if (sel->ex < sel->sx) {
                        /* Cursor (ex) is on the left. */
                        if (px < sel->ex)
                                return (0);

                        if (px > sel->sx)
                                return (0);
                } else {
                        /* Selection start (sx) is on the left. */
                        if (px < sel->sx)
                                return (0);

                        if (px > sel->ex)
                                return (0);
                }
        } else {
                /*
                 * Like emacs, keep the top-left-most character, and drop the
                 * bottom-right-most, regardless of copy direction.
                 */
                if (sel->sy < sel->ey) {
                        /* starting line < ending line -- downward selection. */
                        if (py < sel->sy || py > sel->ey)
                                return (0);

                        if (py == sel->sy && px < sel->sx)
                                return (0);

                        if (sel->modekeys == MODEKEY_EMACS)
                                xx = (sel->ex == 0 ? 0 : sel->ex - 1);
                        else
                                xx = sel->ex;
                        if (py == sel->ey && px > xx)
                                return (0);
                } else if (sel->sy > sel->ey) {
                        /* starting line > ending line -- upward selection. */
                        if (py > sel->sy || py < sel->ey)
                                return (0);

                        if (py == sel->ey && px < sel->ex)
                                return (0);

                        if (sel->modekeys == MODEKEY_EMACS)
                                xx = sel->sx - 1;
                        else
                                xx = sel->sx;
                        if (py == sel->sy && (sel->sx == 0 || px > xx))
                                return (0);
                } else {
                        /* starting line == ending line. */
                        if (py != sel->sy)
                                return (0);

                        if (sel->ex < sel->sx) {
                                /* cursor (ex) is on the left */
                                if (sel->modekeys == MODEKEY_EMACS)
                                        xx = sel->sx - 1;
                                else
                                        xx = sel->sx;
                                if (px > xx || px < sel->ex)
                                        return (0);
                        } else {
                                /* selection start (sx) is on the left */
                                if (sel->modekeys == MODEKEY_EMACS)
                                        xx = (sel->ex == 0 ? 0 : sel->ex - 1);
                                else
                                        xx = sel->ex;
                                if (px < sel->sx || px > xx)
                                        return (0);
                        }
                }
        }

        return (1);
}

/* Get selected grid cell. */
int
screen_select_cell(struct screen *s, struct grid_cell *dst,
    const struct grid_cell *src)
{
        if (s->sel == NULL || s->sel->hidden)
                return (0);

        memcpy(dst, &s->sel->cell, sizeof *dst);
        if (COLOUR_DEFAULT(dst->fg))
                dst->fg = src->fg;
        if (COLOUR_DEFAULT(dst->bg))
                dst->bg = src->bg;
        utf8_copy(&dst->data, &src->data);
        dst->flags = src->flags;

        if (dst->attr & GRID_ATTR_NOATTR)
                dst->attr |= (src->attr & GRID_ATTR_CHARSET);
        else
                dst->attr |= src->attr;
        return (1);
}

/* Reflow wrapped lines. */
static void
screen_reflow(struct screen *s, u_int new_x, u_int *cx, u_int *cy, int cursor)
{
        u_int   wx, wy;

        if (cursor) {
                grid_wrap_position(s->grid, *cx, *cy, &wx, &wy);
                log_debug("%s: cursor %u,%u is %u,%u", __func__, *cx, *cy, wx,
                    wy);
        }

        grid_reflow(s->grid, new_x);

        if (cursor) {
                grid_unwrap_position(s->grid, cx, cy, wx, wy);
                log_debug("%s: new cursor is %u,%u", __func__, *cx, *cy);
        }
        else {
                *cx = 0;
                *cy = s->grid->hsize;
        }
}

/*
 * Enter alternative screen mode. A copy of the visible screen is saved and the
 * history is not updated.
 */
int
screen_alternate_on(struct screen *s, struct grid_cell *gc, int cursor)
{
        u_int   sx, sy;

        if (SCREEN_IS_ALTERNATE(s))
                return 0;
        sx = screen_size_x(s);
        sy = screen_size_y(s);

        s->saved_grid = grid_create(sx, sy, 0);
        grid_duplicate_lines(s->saved_grid, 0, s->grid, screen_hsize(s), sy);
        if (cursor) {
                s->saved_cx = s->cx;
                s->saved_cy = s->cy;
        }
        memcpy(&s->saved_cell, gc, sizeof s->saved_cell);

        grid_view_clear(s->grid, 0, 0, sx, sy, 8);

        s->saved_flags = s->grid->flags;
        s->grid->flags &= ~GRID_HISTORY;

        return 1;
}

/* Exit alternate screen mode and restore the copied grid. */
int
screen_alternate_off(struct screen *s, struct grid_cell *gc, int cursor)
{
        u_int   sx = screen_size_x(s), sy = screen_size_y(s);

        /*
         * If the current size is different, temporarily resize to the old size
         * before copying back.
         */
        if (SCREEN_IS_ALTERNATE(s))
                screen_resize(s, s->saved_grid->sx, s->saved_grid->sy, 0);

        /*
         * Restore the cursor position and cell. This happens even if not
         * currently in the alternate screen.
         */
        if (cursor && s->saved_cx != UINT_MAX && s->saved_cy != UINT_MAX) {
                s->cx = s->saved_cx;
                s->cy = s->saved_cy;
                if (gc != NULL)
                        memcpy(gc, &s->saved_cell, sizeof *gc);
        }

        /* If not in the alternate screen, do nothing more. */
        if (!SCREEN_IS_ALTERNATE(s)) {
                if (s->cx > screen_size_x(s) - 1)
                        s->cx = screen_size_x(s) - 1;
                if (s->cy > screen_size_y(s) - 1)
                        s->cy = screen_size_y(s) - 1;
                return 0;
        }

        /* Restore the saved grid. */
        grid_duplicate_lines(s->grid, screen_hsize(s), s->saved_grid, 0,
            s->saved_grid->sy);

        /*
         * Turn history back on (so resize can use it) and then resize back to
         * the current size.
         */
        if (s->saved_flags & GRID_HISTORY)
                s->grid->flags |= GRID_HISTORY;
        screen_resize(s, sx, sy, 1);

        grid_destroy(s->saved_grid);
        s->saved_grid = NULL;

        if (s->cx > screen_size_x(s) - 1)
                s->cx = screen_size_x(s) - 1;
        if (s->cy > screen_size_y(s) - 1)
                s->cy = screen_size_y(s) - 1;

        return 1;
}

/* Get mode as a string. */
const char *
screen_mode_to_string(int mode)
{
        static char     tmp[1024];

        if (mode == 0)
                return ("NONE");
        if (mode == ALL_MODES)
                return ("ALL");

        *tmp = '\0';
        if (mode & MODE_CURSOR)
                strlcat(tmp, "CURSOR,", sizeof tmp);
        if (mode & MODE_INSERT)
                strlcat(tmp, "INSERT,", sizeof tmp);
        if (mode & MODE_KCURSOR)
                strlcat(tmp, "KCURSOR,", sizeof tmp);
        if (mode & MODE_KKEYPAD)
                strlcat(tmp, "KKEYPAD,", sizeof tmp);
        if (mode & MODE_WRAP)
                strlcat(tmp, "WRAP,", sizeof tmp);
        if (mode & MODE_MOUSE_STANDARD)
                strlcat(tmp, "MOUSE_STANDARD,", sizeof tmp);
        if (mode & MODE_MOUSE_BUTTON)
                strlcat(tmp, "MOUSE_BUTTON,", sizeof tmp);
        if (mode & MODE_CURSOR_BLINKING)
                strlcat(tmp, "CURSOR_BLINKING,", sizeof tmp);
        if (mode & MODE_CURSOR_VERY_VISIBLE)
                strlcat(tmp, "CURSOR_VERY_VISIBLE,", sizeof tmp);
        if (mode & MODE_CURSOR_BLINKING_SET)
                strlcat(tmp, "CURSOR_BLINKING_SET,", sizeof tmp);
        if (mode & MODE_MOUSE_UTF8)
                strlcat(tmp, "MOUSE_UTF8,", sizeof tmp);
        if (mode & MODE_MOUSE_SGR)
                strlcat(tmp, "MOUSE_SGR,", sizeof tmp);
        if (mode & MODE_BRACKETPASTE)
                strlcat(tmp, "BRACKETPASTE,", sizeof tmp);
        if (mode & MODE_FOCUSON)
                strlcat(tmp, "FOCUSON,", sizeof tmp);
        if (mode & MODE_MOUSE_ALL)
                strlcat(tmp, "MOUSE_ALL,", sizeof tmp);
        if (mode & MODE_ORIGIN)
                strlcat(tmp, "ORIGIN,", sizeof tmp);
        if (mode & MODE_CRLF)
                strlcat(tmp, "CRLF,", sizeof tmp);
        if (mode & MODE_KEYS_EXTENDED)
                strlcat(tmp, "KEYS_EXTENDED,", sizeof tmp);
        if (mode & MODE_KEYS_EXTENDED_2)
                strlcat(tmp, "KEYS_EXTENDED_2,", sizeof tmp);
        if (mode & MODE_THEME_UPDATES)
                strlcat(tmp, "THEME_UPDATES,", sizeof tmp);
        if (mode & MODE_SYNC)
                strlcat(tmp, "SYNC,", sizeof tmp);
        if (*tmp != '\0')
                tmp[strlen(tmp) - 1] = '\0';
        return (tmp);
}

/* Convert screen to a string. */
const char *
screen_print(struct screen *s, int line)
{
        static char             *buf;
        static size_t            len = 16384;
        const char              *acs;
        u_int                    x, y;
        int                      n;
        size_t                   last = 0;
        struct utf8_data         ud;
        struct grid_line        *gl;
        struct grid_cell_entry  *gce;

        if (buf == NULL)
                buf = xmalloc(len);

        for (y = 0; y < screen_hsize(s) + s->grid->sy; y++) {
                if (line >= 0 && y != (u_int)line)
                        continue;
                n = snprintf(buf + last, len - last, "%.4d \"", y);
                if (n <= 0 || (u_int)n >= len - last)
                        goto out;
                last += n;

                gl = &s->grid->linedata[y];
                for (x = 0; x < gl->cellused; x++) {
                        gce = &gl->celldata[x];
                        if (gce->flags & GRID_FLAG_PADDING)
                                continue;

                        if (~gce->flags & GRID_FLAG_EXTENDED) {
                                if (last + 2 >= len)
                                        goto out;
                                buf[last++] = gce->data.data;
                        } else if (gce->flags & GRID_FLAG_TAB) {
                                if (last + 2 >= len)
                                        goto out;
                                buf[last++] = '\t';
                        } else if (gce->flags & GRID_ATTR_CHARSET) {
                                acs = tty_acs_get(NULL, gce->data.data);
                                if (acs != NULL)
                                        n = strlen(acs);
                                else {
                                        acs = &gce->data.data;
                                        n = 1;
                                }
                                if (last + n + 1 >= len)
                                        goto out;
                                memcpy(buf + last, acs, n);
                                last += n;
                        } else {
                                utf8_to_data(gl->extddata[gce->offset].data,
                                    &ud);
                                if (ud.size > 0) {
                                        if (last + ud.size + 1 >= len)
                                                goto out;
                                        memcpy(buf + last, ud.data, ud.size);
                                        last += ud.size;
                                }
                        }
                }

                if (last + 3 >= len)
                        goto out;
                buf[last++] = '"';
                buf[last++] = '\n';
        }

out:
        buf[last] = '\0';
        return (buf);
}