Merge branch 'obsd-master'

[tmux.git] / grid.c

/* $OpenBSD$ */

/*
 * Copyright (c) 2008 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 "tmux.h"

/*
 * Grid data. This is the basic data structure that represents what is shown on
 * screen.
 *
 * A grid is a grid of cells (struct grid_cell). Lines are not allocated until
 * cells in that line are written to. The grid is split into history and
 * viewable data with the history starting at row (line) 0 and extending to
 * (hsize - 1); from hsize to hsize + (sy - 1) is the viewable data. All
 * functions in this file work on absolute coordinates, grid-view.c has
 * functions which work on the screen data.
 */

/* Default grid cell data. */
const struct grid_cell grid_default_cell = {
        { { ' ' }, 0, 1, 1 }, 0, 0, 8, 8, 8, 0
};

/*
 * Padding grid cell data. Padding cells are the only zero width cell that
 * appears in the grid - because of this, they are always extended cells.
 */
static const struct grid_cell grid_padding_cell = {
        { { '!' }, 0, 0, 0 }, 0, GRID_FLAG_PADDING, 8, 8, 8, 0
};

/* Cleared grid cell data. */
static const struct grid_cell grid_cleared_cell = {
        { { ' ' }, 0, 1, 1 }, 0, GRID_FLAG_CLEARED, 8, 8, 8, 0
};
static const struct grid_cell_entry grid_cleared_entry = {
        { .data = { 0, 8, 8, ' ' } }, GRID_FLAG_CLEARED
};

/* Store cell in entry. */
static void
grid_store_cell(struct grid_cell_entry *gce, const struct grid_cell *gc,
    u_char c)
{
        gce->flags = (gc->flags & ~GRID_FLAG_CLEARED);

        gce->data.fg = gc->fg & 0xff;
        if (gc->fg & COLOUR_FLAG_256)
                gce->flags |= GRID_FLAG_FG256;

        gce->data.bg = gc->bg & 0xff;
        if (gc->bg & COLOUR_FLAG_256)
                gce->flags |= GRID_FLAG_BG256;

        gce->data.attr = gc->attr;
        gce->data.data = c;
}

/* Check if a cell should be an extended cell. */
static int
grid_need_extended_cell(const struct grid_cell_entry *gce,
    const struct grid_cell *gc)
{
        if (gce->flags & GRID_FLAG_EXTENDED)
                return (1);
        if (gc->attr > 0xff)
                return (1);
        if (gc->data.size != 1 || gc->data.width != 1)
                return (1);
        if ((gc->fg & COLOUR_FLAG_RGB) || (gc->bg & COLOUR_FLAG_RGB))
                return (1);
        if (gc->us != 8) /* only supports 256 or RGB */
                return (1);
        if (gc->link != 0)
                return (1);
        return (0);
}

/* Get an extended cell. */
static void
grid_get_extended_cell(struct grid_line *gl, struct grid_cell_entry *gce,
    int flags)
{
        u_int at = gl->extdsize + 1;

        gl->extddata = xreallocarray(gl->extddata, at, sizeof *gl->extddata);
        gl->extdsize = at;

        gce->offset = at - 1;
        gce->flags = (flags | GRID_FLAG_EXTENDED);
}

/* Set cell as extended. */
static struct grid_extd_entry *
grid_extended_cell(struct grid_line *gl, struct grid_cell_entry *gce,
    const struct grid_cell *gc)
{
        struct grid_extd_entry  *gee;
        int                      flags = (gc->flags & ~GRID_FLAG_CLEARED);
        utf8_char                uc;

        if (~gce->flags & GRID_FLAG_EXTENDED)
                grid_get_extended_cell(gl, gce, flags);
        else if (gce->offset >= gl->extdsize)
                fatalx("offset too big");
        gl->flags |= GRID_LINE_EXTENDED;

        utf8_from_data(&gc->data, &uc);

        gee = &gl->extddata[gce->offset];
        gee->data = uc;
        gee->attr = gc->attr;
        gee->flags = flags;
        gee->fg = gc->fg;
        gee->bg = gc->bg;
        gee->us = gc->us;
        gee->link = gc->link;
        return (gee);
}

/* Free up unused extended cells. */
static void
grid_compact_line(struct grid_line *gl)
{
        int                      new_extdsize = 0;
        struct grid_extd_entry  *new_extddata;
        struct grid_cell_entry  *gce;
        struct grid_extd_entry  *gee;
        u_int                    px, idx;

        if (gl->extdsize == 0)
                return;

        for (px = 0; px < gl->cellsize; px++) {
                gce = &gl->celldata[px];
                if (gce->flags & GRID_FLAG_EXTENDED)
                        new_extdsize++;
        }

        if (new_extdsize == 0) {
                free(gl->extddata);
                gl->extddata = NULL;
                gl->extdsize = 0;
                return;
        }
        new_extddata = xreallocarray(NULL, new_extdsize, sizeof *gl->extddata);

        idx = 0;
        for (px = 0; px < gl->cellsize; px++) {
                gce = &gl->celldata[px];
                if (gce->flags & GRID_FLAG_EXTENDED) {
                        gee = &gl->extddata[gce->offset];
                        memcpy(&new_extddata[idx], gee, sizeof *gee);
                        gce->offset = idx++;
                }
        }

        free(gl->extddata);
        gl->extddata = new_extddata;
        gl->extdsize = new_extdsize;
}

/* Get line data. */
struct grid_line *
grid_get_line(struct grid *gd, u_int line)
{
        return (&gd->linedata[line]);
}

/* Adjust number of lines. */
void
grid_adjust_lines(struct grid *gd, u_int lines)
{
        gd->linedata = xreallocarray(gd->linedata, lines, sizeof *gd->linedata);
}

/* Copy default into a cell. */
static void
grid_clear_cell(struct grid *gd, u_int px, u_int py, u_int bg)
{
        struct grid_line        *gl = &gd->linedata[py];
        struct grid_cell_entry  *gce = &gl->celldata[px];
        struct grid_extd_entry  *gee;

        memcpy(gce, &grid_cleared_entry, sizeof *gce);
        if (bg != 8) {
                if (bg & COLOUR_FLAG_RGB) {
                        grid_get_extended_cell(gl, gce, gce->flags);
                        gee = grid_extended_cell(gl, gce, &grid_cleared_cell);
                        gee->bg = bg;
                } else {
                        if (bg & COLOUR_FLAG_256)
                                gce->flags |= GRID_FLAG_BG256;
                        gce->data.bg = bg;
                }
        }
}

/* Check grid y position. */
static int
grid_check_y(struct grid *gd, const char *from, u_int py)
{
        if (py >= gd->hsize + gd->sy) {
                log_debug("%s: y out of range: %u", from, py);
                return (-1);
        }
        return (0);
}

/* Check if two styles are (visibly) the same. */
int
grid_cells_look_equal(const struct grid_cell *gc1, const struct grid_cell *gc2)
{
        if (gc1->fg != gc2->fg || gc1->bg != gc2->bg)
                return (0);
        if (gc1->attr != gc2->attr || gc1->flags != gc2->flags)
                return (0);
        if (gc1->link != gc2->link)
                return (0);
        return (1);
}

/* Compare grid cells. Return 1 if equal, 0 if not. */
int
grid_cells_equal(const struct grid_cell *gc1, const struct grid_cell *gc2)
{
        if (!grid_cells_look_equal(gc1, gc2))
                return (0);
        if (gc1->data.width != gc2->data.width)
                return (0);
        if (gc1->data.size != gc2->data.size)
                return (0);
        return (memcmp(gc1->data.data, gc2->data.data, gc1->data.size) == 0);
}

/* Free one line. */
static void
grid_free_line(struct grid *gd, u_int py)
{
        free(gd->linedata[py].celldata);
        gd->linedata[py].celldata = NULL;
        free(gd->linedata[py].extddata);
        gd->linedata[py].extddata = NULL;
}

/* Free several lines. */
static void
grid_free_lines(struct grid *gd, u_int py, u_int ny)
{
        u_int   yy;

        for (yy = py; yy < py + ny; yy++)
                grid_free_line(gd, yy);
}

/* Create a new grid. */
struct grid *
grid_create(u_int sx, u_int sy, u_int hlimit)
{
        struct grid     *gd;

        gd = xmalloc(sizeof *gd);
        gd->sx = sx;
        gd->sy = sy;

        if (hlimit != 0)
                gd->flags = GRID_HISTORY;
        else
                gd->flags = 0;

        gd->hscrolled = 0;
        gd->hsize = 0;
        gd->hlimit = hlimit;

        if (gd->sy != 0)
                gd->linedata = xcalloc(gd->sy, sizeof *gd->linedata);
        else
                gd->linedata = NULL;

        return (gd);
}

/* Destroy grid. */
void
grid_destroy(struct grid *gd)
{
        grid_free_lines(gd, 0, gd->hsize + gd->sy);

        free(gd->linedata);

        free(gd);
}

/* Compare grids. */
int
grid_compare(struct grid *ga, struct grid *gb)
{
        struct grid_line        *gla, *glb;
        struct grid_cell         gca, gcb;
        u_int                    xx, yy;

        if (ga->sx != gb->sx || ga->sy != gb->sy)
                return (1);

        for (yy = 0; yy < ga->sy; yy++) {
                gla = &ga->linedata[yy];
                glb = &gb->linedata[yy];
                if (gla->cellsize != glb->cellsize)
                        return (1);
                for (xx = 0; xx < gla->cellsize; xx++) {
                        grid_get_cell(ga, xx, yy, &gca);
                        grid_get_cell(gb, xx, yy, &gcb);
                        if (!grid_cells_equal(&gca, &gcb))
                                return (1);
                }
        }

        return (0);
}

/* Trim lines from the history. */
static void
grid_trim_history(struct grid *gd, u_int ny)
{
        grid_free_lines(gd, 0, ny);
        memmove(&gd->linedata[0], &gd->linedata[ny],
            (gd->hsize + gd->sy - ny) * (sizeof *gd->linedata));
}

/*
 * Collect lines from the history if at the limit. Free the top (oldest) 10%
 * and shift up.
 */
void
grid_collect_history(struct grid *gd)
{
        u_int   ny;

        if (gd->hsize == 0 || gd->hsize < gd->hlimit)
                return;

        ny = gd->hlimit / 10;
        if (ny < 1)
                ny = 1;
        if (ny > gd->hsize)
                ny = gd->hsize;

        /*
         * Free the lines from 0 to ny then move the remaining lines over
         * them.
         */
        grid_trim_history(gd, ny);

        gd->hsize -= ny;
        if (gd->hscrolled > gd->hsize)
                gd->hscrolled = gd->hsize;
}

/* Remove lines from the bottom of the history. */
void
grid_remove_history(struct grid *gd, u_int ny)
{
        u_int   yy;

        if (ny > gd->hsize)
                return;
        for (yy = 0; yy < ny; yy++)
                grid_free_line(gd, gd->hsize + gd->sy - 1 - yy);
        gd->hsize -= ny;
}

/*
 * Scroll the entire visible screen, moving one line into the history. Just
 * allocate a new line at the bottom and move the history size indicator.
 */
void
grid_scroll_history(struct grid *gd, u_int bg)
{
        u_int   yy;

        yy = gd->hsize + gd->sy;
        gd->linedata = xreallocarray(gd->linedata, yy + 1,
            sizeof *gd->linedata);
        grid_empty_line(gd, yy, bg);

        gd->hscrolled++;
        grid_compact_line(&gd->linedata[gd->hsize]);
        gd->linedata[gd->hsize].time = current_time;
        gd->hsize++;
}

/* Clear the history. */
void
grid_clear_history(struct grid *gd)
{
        grid_trim_history(gd, gd->hsize);

        gd->hscrolled = 0;
        gd->hsize = 0;

        gd->linedata = xreallocarray(gd->linedata, gd->sy,
            sizeof *gd->linedata);
}

/* Scroll a region up, moving the top line into the history. */
void
grid_scroll_history_region(struct grid *gd, u_int upper, u_int lower, u_int bg)
{
        struct grid_line        *gl_history, *gl_upper;
        u_int                    yy;

        /* Create a space for a new line. */
        yy = gd->hsize + gd->sy;
        gd->linedata = xreallocarray(gd->linedata, yy + 1,
            sizeof *gd->linedata);

        /* Move the entire screen down to free a space for this line. */
        gl_history = &gd->linedata[gd->hsize];
        memmove(gl_history + 1, gl_history, gd->sy * sizeof *gl_history);

        /* Adjust the region and find its start and end. */
        upper++;
        gl_upper = &gd->linedata[upper];
        lower++;

        /* Move the line into the history. */
        memcpy(gl_history, gl_upper, sizeof *gl_history);
        gl_history->time = current_time;

        /* Then move the region up and clear the bottom line. */
        memmove(gl_upper, gl_upper + 1, (lower - upper) * sizeof *gl_upper);
        grid_empty_line(gd, lower, bg);

        /* Move the history offset down over the line. */
        gd->hscrolled++;
        gd->hsize++;
}

/* Expand line to fit to cell. */
static void
grid_expand_line(struct grid *gd, u_int py, u_int sx, u_int bg)
{
        struct grid_line        *gl;
        u_int                    xx;

        gl = &gd->linedata[py];
        if (sx <= gl->cellsize)
                return;

        if (sx < gd->sx / 4)
                sx = gd->sx / 4;
        else if (sx < gd->sx / 2)
                sx = gd->sx / 2;
        else if (gd->sx > sx)
                sx = gd->sx;

        gl->celldata = xreallocarray(gl->celldata, sx, sizeof *gl->celldata);
        for (xx = gl->cellsize; xx < sx; xx++)
                grid_clear_cell(gd, xx, py, bg);
        gl->cellsize = sx;
}

/* Empty a line and set background colour if needed. */
void
grid_empty_line(struct grid *gd, u_int py, u_int bg)
{
        memset(&gd->linedata[py], 0, sizeof gd->linedata[py]);
        if (!COLOUR_DEFAULT(bg))
                grid_expand_line(gd, py, gd->sx, bg);
}

/* Peek at grid line. */
const struct grid_line *
grid_peek_line(struct grid *gd, u_int py)
{
        if (grid_check_y(gd, __func__, py) != 0)
                return (NULL);
        return (&gd->linedata[py]);
}

/* Get cell from line. */
static void
grid_get_cell1(struct grid_line *gl, u_int px, struct grid_cell *gc)
{
        struct grid_cell_entry  *gce = &gl->celldata[px];
        struct grid_extd_entry  *gee;

        if (gce->flags & GRID_FLAG_EXTENDED) {
                if (gce->offset >= gl->extdsize)
                        memcpy(gc, &grid_default_cell, sizeof *gc);
                else {
                        gee = &gl->extddata[gce->offset];
                        gc->flags = gee->flags;
                        gc->attr = gee->attr;
                        gc->fg = gee->fg;
                        gc->bg = gee->bg;
                        gc->us = gee->us;
                        gc->link = gee->link;
                        utf8_to_data(gee->data, &gc->data);
                }
                return;
        }

        gc->flags = gce->flags & ~(GRID_FLAG_FG256|GRID_FLAG_BG256);
        gc->attr = gce->data.attr;
        gc->fg = gce->data.fg;
        if (gce->flags & GRID_FLAG_FG256)
                gc->fg |= COLOUR_FLAG_256;
        gc->bg = gce->data.bg;
        if (gce->flags & GRID_FLAG_BG256)
                gc->bg |= COLOUR_FLAG_256;
        gc->us = 8;
        utf8_set(&gc->data, gce->data.data);
        gc->link = 0;
}

/* Get cell for reading. */
void
grid_get_cell(struct grid *gd, u_int px, u_int py, struct grid_cell *gc)
{
        if (grid_check_y(gd, __func__, py) != 0 ||
            px >= gd->linedata[py].cellsize)
                memcpy(gc, &grid_default_cell, sizeof *gc);
        else
                grid_get_cell1(&gd->linedata[py], px, gc);
}

/* Set cell at position. */
void
grid_set_cell(struct grid *gd, u_int px, u_int py, const struct grid_cell *gc)
{
        struct grid_line        *gl;
        struct grid_cell_entry  *gce;

        if (grid_check_y(gd, __func__, py) != 0)
                return;

        grid_expand_line(gd, py, px + 1, 8);

        gl = &gd->linedata[py];
        if (px + 1 > gl->cellused)
                gl->cellused = px + 1;

        gce = &gl->celldata[px];
        if (grid_need_extended_cell(gce, gc))
                grid_extended_cell(gl, gce, gc);
        else
                grid_store_cell(gce, gc, gc->data.data[0]);
}

/* Set padding at position. */
void
grid_set_padding(struct grid *gd, u_int px, u_int py)
{
        grid_set_cell(gd, px, py, &grid_padding_cell);
}

/* Set cells at position. */
void
grid_set_cells(struct grid *gd, u_int px, u_int py, const struct grid_cell *gc,
    const char *s, size_t slen)
{
        struct grid_line        *gl;
        struct grid_cell_entry  *gce;
        struct grid_extd_entry  *gee;
        u_int                    i;

        if (grid_check_y(gd, __func__, py) != 0)
                return;

        grid_expand_line(gd, py, px + slen, 8);

        gl = &gd->linedata[py];
        if (px + slen > gl->cellused)
                gl->cellused = px + slen;

        for (i = 0; i < slen; i++) {
                gce = &gl->celldata[px + i];
                if (grid_need_extended_cell(gce, gc)) {
                        gee = grid_extended_cell(gl, gce, gc);
                        gee->data = utf8_build_one(s[i]);
                } else
                        grid_store_cell(gce, gc, s[i]);
        }
}

/* Clear area. */
void
grid_clear(struct grid *gd, u_int px, u_int py, u_int nx, u_int ny, u_int bg)
{
        struct grid_line        *gl;
        u_int                    xx, yy, ox, sx;

        if (nx == 0 || ny == 0)
                return;

        if (px == 0 && nx == gd->sx) {
                grid_clear_lines(gd, py, ny, bg);
                return;
        }

        if (grid_check_y(gd, __func__, py) != 0)
                return;
        if (grid_check_y(gd, __func__, py + ny - 1) != 0)
                return;

        for (yy = py; yy < py + ny; yy++) {
                gl = &gd->linedata[yy];

                sx = gd->sx;
                if (sx > gl->cellsize)
                        sx = gl->cellsize;
                ox = nx;
                if (COLOUR_DEFAULT(bg)) {
                        if (px > sx)
                                continue;
                        if (px + nx > sx)
                                ox = sx - px;
                }

                grid_expand_line(gd, yy, px + ox, 8); /* default bg first */
                for (xx = px; xx < px + ox; xx++)
                        grid_clear_cell(gd, xx, yy, bg);
        }
}

/* Clear lines. This just frees and truncates the lines. */
void
grid_clear_lines(struct grid *gd, u_int py, u_int ny, u_int bg)
{
        u_int   yy;

        if (ny == 0)
                return;

        if (grid_check_y(gd, __func__, py) != 0)
                return;
        if (grid_check_y(gd, __func__, py + ny - 1) != 0)
                return;

        for (yy = py; yy < py + ny; yy++) {
                grid_free_line(gd, yy);
                grid_empty_line(gd, yy, bg);
        }
        if (py != 0)
                gd->linedata[py - 1].flags &= ~GRID_LINE_WRAPPED;
}

/* Move a group of lines. */
void
grid_move_lines(struct grid *gd, u_int dy, u_int py, u_int ny, u_int bg)
{
        u_int   yy;

        if (ny == 0 || py == dy)
                return;

        if (grid_check_y(gd, __func__, py) != 0)
                return;
        if (grid_check_y(gd, __func__, py + ny - 1) != 0)
                return;
        if (grid_check_y(gd, __func__, dy) != 0)
                return;
        if (grid_check_y(gd, __func__, dy + ny - 1) != 0)
                return;

        /* Free any lines which are being replaced. */
        for (yy = dy; yy < dy + ny; yy++) {
                if (yy >= py && yy < py + ny)
                        continue;
                grid_free_line(gd, yy);
        }
        if (dy != 0)
                gd->linedata[dy - 1].flags &= ~GRID_LINE_WRAPPED;

        memmove(&gd->linedata[dy], &gd->linedata[py],
            ny * (sizeof *gd->linedata));

        /*
         * Wipe any lines that have been moved (without freeing them - they are
         * still present).
         */
        for (yy = py; yy < py + ny; yy++) {
                if (yy < dy || yy >= dy + ny)
                        grid_empty_line(gd, yy, bg);
        }
        if (py != 0 && (py < dy || py >= dy + ny))
                gd->linedata[py - 1].flags &= ~GRID_LINE_WRAPPED;
}

/* Move a group of cells. */
void
grid_move_cells(struct grid *gd, u_int dx, u_int px, u_int py, u_int nx,
    u_int bg)
{
        struct grid_line        *gl;
        u_int                    xx;

        if (nx == 0 || px == dx)
                return;

        if (grid_check_y(gd, __func__, py) != 0)
                return;
        gl = &gd->linedata[py];

        grid_expand_line(gd, py, px + nx, 8);
        grid_expand_line(gd, py, dx + nx, 8);
        memmove(&gl->celldata[dx], &gl->celldata[px],
            nx * sizeof *gl->celldata);
        if (dx + nx > gl->cellused)
                gl->cellused = dx + nx;

        /* Wipe any cells that have been moved. */
        for (xx = px; xx < px + nx; xx++) {
                if (xx >= dx && xx < dx + nx)
                        continue;
                grid_clear_cell(gd, xx, py, bg);
        }
}

/* Get ANSI foreground sequence. */
static size_t
grid_string_cells_fg(const struct grid_cell *gc, int *values)
{
        size_t  n;
        u_char  r, g, b;

        n = 0;
        if (gc->fg & COLOUR_FLAG_256) {
                values[n++] = 38;
                values[n++] = 5;
                values[n++] = gc->fg & 0xff;
        } else if (gc->fg & COLOUR_FLAG_RGB) {
                values[n++] = 38;
                values[n++] = 2;
                colour_split_rgb(gc->fg, &r, &g, &b);
                values[n++] = r;
                values[n++] = g;
                values[n++] = b;
        } else {
                switch (gc->fg) {
                case 0:
                case 1:
                case 2:
                case 3:
                case 4:
                case 5:
                case 6:
                case 7:
                        values[n++] = gc->fg + 30;
                        break;
                case 8:
                        values[n++] = 39;
                        break;
                case 90:
                case 91:
                case 92:
                case 93:
                case 94:
                case 95:
                case 96:
                case 97:
                        values[n++] = gc->fg;
                        break;
                }
        }
        return (n);
}

/* Get ANSI background sequence. */
static size_t
grid_string_cells_bg(const struct grid_cell *gc, int *values)
{
        size_t  n;
        u_char  r, g, b;

        n = 0;
        if (gc->bg & COLOUR_FLAG_256) {
                values[n++] = 48;
                values[n++] = 5;
                values[n++] = gc->bg & 0xff;
        } else if (gc->bg & COLOUR_FLAG_RGB) {
                values[n++] = 48;
                values[n++] = 2;
                colour_split_rgb(gc->bg, &r, &g, &b);
                values[n++] = r;
                values[n++] = g;
                values[n++] = b;
        } else {
                switch (gc->bg) {
                case 0:
                case 1:
                case 2:
                case 3:
                case 4:
                case 5:
                case 6:
                case 7:
                        values[n++] = gc->bg + 40;
                        break;
                case 8:
                        values[n++] = 49;
                        break;
                case 90:
                case 91:
                case 92:
                case 93:
                case 94:
                case 95:
                case 96:
                case 97:
                        values[n++] = gc->bg + 10;
                        break;
                }
        }
        return (n);
}

/* Get underscore colour sequence. */
static size_t
grid_string_cells_us(const struct grid_cell *gc, int *values)
{
        size_t  n;
        u_char  r, g, b;

        n = 0;
        if (gc->us & COLOUR_FLAG_256) {
                values[n++] = 58;
                values[n++] = 5;
                values[n++] = gc->us & 0xff;
        } else if (gc->us & COLOUR_FLAG_RGB) {
                values[n++] = 58;
                values[n++] = 2;
                colour_split_rgb(gc->us, &r, &g, &b);
                values[n++] = r;
                values[n++] = g;
                values[n++] = b;
        }
        return (n);
}

/* Add on SGR code. */
static void
grid_string_cells_add_code(char *buf, size_t len, u_int n, int *s, int *newc,
    int *oldc, size_t nnewc, size_t noldc, int flags)
{
        u_int   i;
        char    tmp[64];
        int     reset = (n != 0 && s[0] == 0);

        if (nnewc == 0)
                return; /* no code to add */
        if (!reset &&
            nnewc == noldc &&
            memcmp(newc, oldc, nnewc * sizeof newc[0]) == 0)
                return; /* no reset and colour unchanged */
        if (reset && (newc[0] == 49 || newc[0] == 39))
                return; /* reset and colour default */

        if (flags & GRID_STRING_ESCAPE_SEQUENCES)
                strlcat(buf, "\\033[", len);
        else
                strlcat(buf, "\033[", len);
        for (i = 0; i < nnewc; i++) {
                if (i + 1 < nnewc)
                        xsnprintf(tmp, sizeof tmp, "%d;", newc[i]);
                else
                        xsnprintf(tmp, sizeof tmp, "%d", newc[i]);
                strlcat(buf, tmp, len);
        }
        strlcat(buf, "m", len);
}

static int
grid_string_cells_add_hyperlink(char *buf, size_t len, const char *id,
    const char *uri, int flags)
{
        char    *tmp;

        if (strlen(uri) + strlen(id) + 17 >= len)
                return (0);

        if (flags & GRID_STRING_ESCAPE_SEQUENCES)
                strlcat(buf, "\\033]8;", len);
        else
                strlcat(buf, "\033]8;", len);
        if (*id != '\0') {
                xasprintf(&tmp, "id=%s;", id);
                strlcat(buf, tmp, len);
                free(tmp);
        } else
                strlcat(buf, ";", len);
        strlcat(buf, uri, len);
        if (flags & GRID_STRING_ESCAPE_SEQUENCES)
                strlcat(buf, "\\033\\\\", len);
        else
                strlcat(buf, "\033\\", len);
        return (1);
}

/*
 * Returns ANSI code to set particular attributes (colour, bold and so on)
 * given a current state.
 */
static void
grid_string_cells_code(const struct grid_cell *lastgc,
    const struct grid_cell *gc, char *buf, size_t len, int flags,
    struct screen *sc, int *has_link)
{
        int                      oldc[64], newc[64], s[128];
        size_t                   noldc, nnewc, n, i;
        u_int                    attr = gc->attr, lastattr = lastgc->attr;
        char                     tmp[64];
        const char              *uri, *id;

        static const struct {
                u_int   mask;
                u_int   code;
        } attrs[] = {
                { GRID_ATTR_BRIGHT, 1 },
                { GRID_ATTR_DIM, 2 },
                { GRID_ATTR_ITALICS, 3 },
                { GRID_ATTR_UNDERSCORE, 4 },
                { GRID_ATTR_BLINK, 5 },
                { GRID_ATTR_REVERSE, 7 },
                { GRID_ATTR_HIDDEN, 8 },
                { GRID_ATTR_STRIKETHROUGH, 9 },
                { GRID_ATTR_UNDERSCORE_2, 42 },
                { GRID_ATTR_UNDERSCORE_3, 43 },
                { GRID_ATTR_UNDERSCORE_4, 44 },
                { GRID_ATTR_UNDERSCORE_5, 45 },
                { GRID_ATTR_OVERLINE, 53 },
        };
        n = 0;

        /* If any attribute is removed, begin with 0. */
        for (i = 0; i < nitems(attrs); i++) {
                if (((~attr & attrs[i].mask) &&
                    (lastattr & attrs[i].mask)) ||
                    (lastgc->us != 8 && gc->us == 8)) {
                        s[n++] = 0;
                        lastattr &= GRID_ATTR_CHARSET;
                        break;
                }
        }
        /* For each attribute that is newly set, add its code. */
        for (i = 0; i < nitems(attrs); i++) {
                if ((attr & attrs[i].mask) && !(lastattr & attrs[i].mask))
                        s[n++] = attrs[i].code;
        }

        /* Write the attributes. */
        *buf = '\0';
        if (n > 0) {
                if (flags & GRID_STRING_ESCAPE_SEQUENCES)
                        strlcat(buf, "\\033[", len);
                else
                        strlcat(buf, "\033[", len);
                for (i = 0; i < n; i++) {
                        if (s[i] < 10)
                                xsnprintf(tmp, sizeof tmp, "%d", s[i]);
                        else {
                                xsnprintf(tmp, sizeof tmp, "%d:%d", s[i] / 10,
                                    s[i] % 10);
                        }
                        strlcat(buf, tmp, len);
                        if (i + 1 < n)
                                strlcat(buf, ";", len);
                }
                strlcat(buf, "m", len);
        }

        /* If the foreground colour changed, write its parameters. */
        nnewc = grid_string_cells_fg(gc, newc);
        noldc = grid_string_cells_fg(lastgc, oldc);
        grid_string_cells_add_code(buf, len, n, s, newc, oldc, nnewc, noldc,
            flags);

        /* If the background colour changed, append its parameters. */
        nnewc = grid_string_cells_bg(gc, newc);
        noldc = grid_string_cells_bg(lastgc, oldc);
        grid_string_cells_add_code(buf, len, n, s, newc, oldc, nnewc, noldc,
            flags);

        /* If the underscore colour changed, append its parameters. */
        nnewc = grid_string_cells_us(gc, newc);
        noldc = grid_string_cells_us(lastgc, oldc);
        grid_string_cells_add_code(buf, len, n, s, newc, oldc, nnewc, noldc,
            flags);

        /* Append shift in/shift out if needed. */
        if ((attr & GRID_ATTR_CHARSET) && !(lastattr & GRID_ATTR_CHARSET)) {
                if (flags & GRID_STRING_ESCAPE_SEQUENCES)
                        strlcat(buf, "\\016", len); /* SO */
                else
                        strlcat(buf, "\016", len);  /* SO */
        }
        if (!(attr & GRID_ATTR_CHARSET) && (lastattr & GRID_ATTR_CHARSET)) {
                if (flags & GRID_STRING_ESCAPE_SEQUENCES)
                        strlcat(buf, "\\017", len); /* SI */
                else
                        strlcat(buf, "\017", len);  /* SI */
        }

        /* Add hyperlink if changed. */
        if (sc != NULL && sc->hyperlinks != NULL && lastgc->link != gc->link) {
                if (hyperlinks_get(sc->hyperlinks, gc->link, &uri, &id, NULL)) {
                        *has_link = grid_string_cells_add_hyperlink(buf, len,
                            id, uri, flags);
                } else if (*has_link) {
                        grid_string_cells_add_hyperlink(buf, len, "", "",
                            flags);
                        *has_link = 0;
                }
        }
}

/* Convert cells into a string. */
char *
grid_string_cells(struct grid *gd, u_int px, u_int py, u_int nx,
    struct grid_cell **lastgc, int flags, struct screen *s)
{
        struct grid_cell         gc;
        static struct grid_cell  lastgc1;
        const char              *data;
        char                    *buf, code[8192];
        size_t                   len, off, size, codelen;
        u_int                    xx, end;
        int                      has_link = 0;
        const struct grid_line  *gl;

        if (lastgc != NULL && *lastgc == NULL) {
                memcpy(&lastgc1, &grid_default_cell, sizeof lastgc1);
                *lastgc = &lastgc1;
        }

        len = 128;
        buf = xmalloc(len);
        off = 0;

        gl = grid_peek_line(gd, py);
        if (flags & GRID_STRING_EMPTY_CELLS)
                end = gl->cellsize;
        else
                end = gl->cellused;
        for (xx = px; xx < px + nx; xx++) {
                if (gl == NULL || xx >= end)
                        break;
                grid_get_cell(gd, xx, py, &gc);
                if (gc.flags & GRID_FLAG_PADDING)
                        continue;

                if (flags & GRID_STRING_WITH_SEQUENCES) {
                        grid_string_cells_code(*lastgc, &gc, code, sizeof code,
                            flags, s, &has_link);
                        codelen = strlen(code);
                        memcpy(*lastgc, &gc, sizeof **lastgc);
                } else
                        codelen = 0;

                data = gc.data.data;
                size = gc.data.size;
                if ((flags & GRID_STRING_ESCAPE_SEQUENCES) &&
                    size == 1 &&
                    *data == '\\') {
                        data = "\\\\";
                        size = 2;
                }

                while (len < off + size + codelen + 1) {
                        buf = xreallocarray(buf, 2, len);
                        len *= 2;
                }

                if (codelen != 0) {
                        memcpy(buf + off, code, codelen);
                        off += codelen;
                }
                memcpy(buf + off, data, size);
                off += size;
        }

        if (has_link) {
                grid_string_cells_add_hyperlink(code, sizeof code, "", "",
                    flags);
                codelen = strlen(code);
                while (len < off + size + codelen + 1) {
                        buf = xreallocarray(buf, 2, len);
                        len *= 2;
                }
                memcpy(buf + off, code, codelen);
                off += codelen;
        }

        if (flags & GRID_STRING_TRIM_SPACES) {
                while (off > 0 && buf[off - 1] == ' ')
                        off--;
        }
        buf[off] = '\0';

        return (buf);
}

/*
 * Duplicate a set of lines between two grids. Both source and destination
 * should be big enough.
 */
void
grid_duplicate_lines(struct grid *dst, u_int dy, struct grid *src, u_int sy,
    u_int ny)
{
        struct grid_line        *dstl, *srcl;
        u_int                    yy;

        if (dy + ny > dst->hsize + dst->sy)
                ny = dst->hsize + dst->sy - dy;
        if (sy + ny > src->hsize + src->sy)
                ny = src->hsize + src->sy - sy;
        grid_free_lines(dst, dy, ny);

        for (yy = 0; yy < ny; yy++) {
                srcl = &src->linedata[sy];
                dstl = &dst->linedata[dy];

                memcpy(dstl, srcl, sizeof *dstl);
                if (srcl->cellsize != 0) {
                        dstl->celldata = xreallocarray(NULL,
                            srcl->cellsize, sizeof *dstl->celldata);
                        memcpy(dstl->celldata, srcl->celldata,
                            srcl->cellsize * sizeof *dstl->celldata);
                } else
                        dstl->celldata = NULL;
                if (srcl->extdsize != 0) {
                        dstl->extdsize = srcl->extdsize;
                        dstl->extddata = xreallocarray(NULL, dstl->extdsize,
                            sizeof *dstl->extddata);
                        memcpy(dstl->extddata, srcl->extddata, dstl->extdsize *
                            sizeof *dstl->extddata);
                } else
                        dstl->extddata = NULL;

                sy++;
                dy++;
        }
}

/* Mark line as dead. */
static void
grid_reflow_dead(struct grid_line *gl)
{
        memset(gl, 0, sizeof *gl);
        gl->flags = GRID_LINE_DEAD;
}

/* Add lines, return the first new one. */
static struct grid_line *
grid_reflow_add(struct grid *gd, u_int n)
{
        struct grid_line        *gl;
        u_int                    sy = gd->sy + n;

        gd->linedata = xreallocarray(gd->linedata, sy, sizeof *gd->linedata);
        gl = &gd->linedata[gd->sy];
        memset(gl, 0, n * (sizeof *gl));
        gd->sy = sy;
        return (gl);
}

/* Move a line across. */
static struct grid_line *
grid_reflow_move(struct grid *gd, struct grid_line *from)
{
        struct grid_line        *to;

        to = grid_reflow_add(gd, 1);
        memcpy(to, from, sizeof *to);
        grid_reflow_dead(from);
        return (to);
}

/* Join line below onto this one. */
static void
grid_reflow_join(struct grid *target, struct grid *gd, u_int sx, u_int yy,
    u_int width, int already)
{
        struct grid_line        *gl, *from = NULL;
        struct grid_cell         gc;
        u_int                    lines, left, i, to, line, want = 0;
        u_int                    at;
        int                      wrapped = 1;

        /*
         * Add a new target line.
         */
        if (!already) {
                to = target->sy;
                gl = grid_reflow_move(target, &gd->linedata[yy]);
        } else {
                to = target->sy - 1;
                gl = &target->linedata[to];
        }
        at = gl->cellused;

        /*
         * Loop until no more to consume or the target line is full.
         */
        lines = 0;
        for (;;) {
                /*
                 * If this is now the last line, there is nothing more to be
                 * done.
                 */
                if (yy + 1 + lines == gd->hsize + gd->sy)
                        break;
                line = yy + 1 + lines;

                /* If the next line is empty, skip it. */
                if (~gd->linedata[line].flags & GRID_LINE_WRAPPED)
                        wrapped = 0;
                if (gd->linedata[line].cellused == 0) {
                        if (!wrapped)
                                break;
                        lines++;
                        continue;
                }

                /*
                 * Is the destination line now full? Copy the first character
                 * separately because we need to leave "from" set to the last
                 * line if this line is full.
                 */
                grid_get_cell1(&gd->linedata[line], 0, &gc);
                if (width + gc.data.width > sx)
                        break;
                width += gc.data.width;
                grid_set_cell(target, at, to, &gc);
                at++;

                /* Join as much more as possible onto the current line. */
                from = &gd->linedata[line];
                for (want = 1; want < from->cellused; want++) {
                        grid_get_cell1(from, want, &gc);
                        if (width + gc.data.width > sx)
                                break;
                        width += gc.data.width;

                        grid_set_cell(target, at, to, &gc);
                        at++;
                }
                lines++;

                /*
                 * If this line wasn't wrapped or we didn't consume the entire
                 * line, don't try to join any further lines.
                 */
                if (!wrapped || want != from->cellused || width == sx)
                        break;
        }
        if (lines == 0)
                return;

        /*
         * If we didn't consume the entire final line, then remove what we did
         * consume. If we consumed the entire line and it wasn't wrapped,
         * remove the wrap flag from this line.
         */
        left = from->cellused - want;
        if (left != 0) {
                grid_move_cells(gd, 0, want, yy + lines, left, 8);
                from->cellsize = from->cellused = left;
                lines--;
        } else if (!wrapped)
                gl->flags &= ~GRID_LINE_WRAPPED;

        /* Remove the lines that were completely consumed. */
        for (i = yy + 1; i < yy + 1 + lines; i++) {
                free(gd->linedata[i].celldata);
                free(gd->linedata[i].extddata);
                grid_reflow_dead(&gd->linedata[i]);
        }

        /* Adjust scroll position. */
        if (gd->hscrolled > to + lines)
                gd->hscrolled -= lines;
        else if (gd->hscrolled > to)
                gd->hscrolled = to;
}

/* Split this line into several new ones */
static void
grid_reflow_split(struct grid *target, struct grid *gd, u_int sx, u_int yy,
    u_int at)
{
        struct grid_line        *gl = &gd->linedata[yy], *first;
        struct grid_cell         gc;
        u_int                    line, lines, width, i, xx;
        u_int                    used = gl->cellused;
        int                      flags = gl->flags;

        /* How many lines do we need to insert? We know we need at least two. */
        if (~gl->flags & GRID_LINE_EXTENDED)
                lines = 1 + (gl->cellused - 1) / sx;
        else {
                lines = 2;
                width = 0;
                for (i = at; i < used; i++) {
                        grid_get_cell1(gl, i, &gc);
                        if (width + gc.data.width > sx) {
                                lines++;
                                width = 0;
                        }
                        width += gc.data.width;
                }
        }

        /* Insert new lines. */
        line = target->sy + 1;
        first = grid_reflow_add(target, lines);

        /* Copy sections from the original line. */
        width = 0;
        xx = 0;
        for (i = at; i < used; i++) {
                grid_get_cell1(gl, i, &gc);
                if (width + gc.data.width > sx) {
                        target->linedata[line].flags |= GRID_LINE_WRAPPED;

                        line++;
                        width = 0;
                        xx = 0;
                }
                width += gc.data.width;
                grid_set_cell(target, xx, line, &gc);
                xx++;
        }
        if (flags & GRID_LINE_WRAPPED)
                target->linedata[line].flags |= GRID_LINE_WRAPPED;

        /* Move the remainder of the original line. */
        gl->cellsize = gl->cellused = at;
        gl->flags |= GRID_LINE_WRAPPED;
        memcpy(first, gl, sizeof *first);
        grid_reflow_dead(gl);

        /* Adjust the scroll position. */
        if (yy <= gd->hscrolled)
                gd->hscrolled += lines - 1;

        /*
         * If the original line had the wrapped flag and there is still space
         * in the last new line, try to join with the next lines.
         */
        if (width < sx && (flags & GRID_LINE_WRAPPED))
                grid_reflow_join(target, gd, sx, yy, width, 1);
}

/* Reflow lines on grid to new width. */
void
grid_reflow(struct grid *gd, u_int sx)
{
        struct grid             *target;
        struct grid_line        *gl;
        struct grid_cell         gc;
        u_int                    yy, width, i, at;

        /*
         * Create a destination grid. This is just used as a container for the
         * line data and may not be fully valid.
         */
        target = grid_create(gd->sx, 0, 0);

        /*
         * Loop over each source line.
         */
        for (yy = 0; yy < gd->hsize + gd->sy; yy++) {
                gl = &gd->linedata[yy];
                if (gl->flags & GRID_LINE_DEAD)
                        continue;

                /*
                 * Work out the width of this line. at is the point at which
                 * the available width is hit, and width is the full line
                 * width.
                 */
                at = width = 0;
                if (~gl->flags & GRID_LINE_EXTENDED) {
                        width = gl->cellused;
                        if (width > sx)
                                at = sx;
                        else
                                at = width;
                } else {
                        for (i = 0; i < gl->cellused; i++) {
                                grid_get_cell1(gl, i, &gc);
                                if (at == 0 && width + gc.data.width > sx)
                                        at = i;
                                width += gc.data.width;
                        }
                }

                /*
                 * If the line is exactly right, just move it across
                 * unchanged.
                 */
                if (width == sx) {
                        grid_reflow_move(target, gl);
                        continue;
                }

                /*
                 * If the line is too big, it needs to be split, whether or not
                 * it was previously wrapped.
                 */
                if (width > sx) {
                        grid_reflow_split(target, gd, sx, yy, at);
                        continue;
                }

                /*
                 * If the line was previously wrapped, join as much as possible
                 * of the next line.
                 */
                if (gl->flags & GRID_LINE_WRAPPED)
                        grid_reflow_join(target, gd, sx, yy, width, 0);
                else
                        grid_reflow_move(target, gl);
        }

        /*
         * Replace the old grid with the new.
         */
        if (target->sy < gd->sy)
                grid_reflow_add(target, gd->sy - target->sy);
        gd->hsize = target->sy - gd->sy;
        if (gd->hscrolled > gd->hsize)
                gd->hscrolled = gd->hsize;
        free(gd->linedata);
        gd->linedata = target->linedata;
        free(target);
}

/* Convert to position based on wrapped lines. */
void
grid_wrap_position(struct grid *gd, u_int px, u_int py, u_int *wx, u_int *wy)
{
        u_int   ax = 0, ay = 0, yy;

        for (yy = 0; yy < py; yy++) {
                if (gd->linedata[yy].flags & GRID_LINE_WRAPPED)
                        ax += gd->linedata[yy].cellused;
                else {
                        ax = 0;
                        ay++;
                }
        }
        if (px >= gd->linedata[yy].cellused)
                ax = UINT_MAX;
        else
                ax += px;
        *wx = ax;
        *wy = ay;
}

/* Convert position based on wrapped lines back. */
void
grid_unwrap_position(struct grid *gd, u_int *px, u_int *py, u_int wx, u_int wy)
{
        u_int   yy, ay = 0;

        for (yy = 0; yy < gd->hsize + gd->sy - 1; yy++) {
                if (ay == wy)
                        break;
                if (~gd->linedata[yy].flags & GRID_LINE_WRAPPED)
                        ay++;
        }

        /*
         * yy is now 0 on the unwrapped line which contains wx. Walk forwards
         * until we find the end or the line now containing wx.
         */
        if (wx == UINT_MAX) {
                while (gd->linedata[yy].flags & GRID_LINE_WRAPPED)
                        yy++;
                wx = gd->linedata[yy].cellused;
        } else {
                while (gd->linedata[yy].flags & GRID_LINE_WRAPPED) {
                        if (wx < gd->linedata[yy].cellused)
                                break;
                        wx -= gd->linedata[yy].cellused;
                        yy++;
                }
        }
        *px = wx;
        *py = yy;
}

/* Get length of line. */
u_int
grid_line_length(struct grid *gd, u_int py)
{
        struct grid_cell        gc;
        u_int                   px;

        px = grid_get_line(gd, py)->cellsize;
        if (px > gd->sx)
                px = gd->sx;
        while (px > 0) {
                grid_get_cell(gd, px - 1, py, &gc);
                if ((gc.flags & GRID_FLAG_PADDING) ||
                    gc.data.size != 1 ||
                    *gc.data.data != ' ')
                        break;
                px--;
        }
        return (px);
}