/* $OpenBSD$ */

/*
* Copyright (c) 2008 Nicholas Marriott <[email protected]>
*
* 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 = (void *)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);
}