/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009 The FreeBSD Foundation
 *
 * This software was developed by Ed Schouten under sponsorship from the
 * FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/refcount.h>
#include <sys/systm.h>

#include <dev/vt/vt.h>

static MALLOC_DEFINE(M_VTFONT, "vtfont", "vt font");

/* Some limits to prevent abnormal fonts from being loaded. */
#define VTFONT_MAXMAPPINGS      65536
#define VTFONT_MAXGLYPHS        131072
#define VTFONT_MAXGLYPHSIZE     2097152
#define VTFONT_MAXDIMENSION     128

static uint16_t
vtfont_bisearch(const vfnt_map_t *map, unsigned int len, uint32_t src)
{
        int min, mid, max;

        min = 0;
        max = len - 1;

        /* Empty font map. */
        if (len == 0)
                return (0);
        /* Character below minimal entry. */
        if (src < map[0].vfm_src)
                return (0);
        /* Optimization: ASCII characters occur very often. */
        if (src <= map[0].vfm_src + map[0].vfm_len)
                return (src - map[0].vfm_src + map[0].vfm_dst);
        /* Character above maximum entry. */
        if (src > map[max].vfm_src + map[max].vfm_len)
                return (0);

        /* Binary search. */
        while (max >= min) {
                mid = (min + max) / 2;
                if (src < map[mid].vfm_src)
                        max = mid - 1;
                else if (src > map[mid].vfm_src + map[mid].vfm_len)
                        min = mid + 1;
                else
                        return (src - map[mid].vfm_src + map[mid].vfm_dst);
        }

        return (0);
}

const uint8_t *
vtfont_lookup(const struct vt_font *vf, term_char_t c)
{
        uint32_t src;
        uint16_t dst;
        size_t stride;
        unsigned int normal_map;
        unsigned int bold_map;

        src = TCHAR_CHARACTER(c);
        if (TCHAR_FORMAT(c) & TF_CJK_RIGHT) {
                normal_map = VFNT_MAP_NORMAL_RIGHT;
                bold_map = VFNT_MAP_BOLD_RIGHT;
        } else {
                normal_map = VFNT_MAP_NORMAL;
                bold_map = VFNT_MAP_BOLD;
        }

        if (TCHAR_FORMAT(c) & TF_BOLD) {
                dst = vtfont_bisearch(vf->vf_map[bold_map],
                    vf->vf_map_count[bold_map], src);
                if (dst != 0)
                        goto found;
        }
        dst = vtfont_bisearch(vf->vf_map[normal_map],
            vf->vf_map_count[normal_map], src);

found:
        stride = howmany(vf->vf_width, 8) * vf->vf_height;
        return (&vf->vf_bytes[dst * stride]);
}

struct vt_font *
vtfont_ref(struct vt_font *vf)
{

        refcount_acquire(&vf->vf_refcount);
        return (vf);
}

void
vtfont_unref(struct vt_font *vf)
{
        unsigned int i;

        if (refcount_release(&vf->vf_refcount)) {
                for (i = 0; i < VFNT_MAPS; i++)
                        free(vf->vf_map[i], M_VTFONT);
                free(vf->vf_bytes, M_VTFONT);
                free(vf, M_VTFONT);
        }
}

static int
vtfont_validate_map(vfnt_map_t *vfm, unsigned int length,
    unsigned int glyph_count)
{
        unsigned int i, last = 0;

        for (i = 0; i < length; i++) {
                /* Not ordered. */
                if (i > 0 && vfm[i].vfm_src <= last)
                        return (EINVAL);
                /*
                 * Destination extends amount of glyphs.
                 */
                if (vfm[i].vfm_dst >= glyph_count ||
                    vfm[i].vfm_dst + vfm[i].vfm_len >= glyph_count)
                        return (EINVAL);
                last = vfm[i].vfm_src + vfm[i].vfm_len;
        }

        return (0);
}

int
vtfont_load(vfnt_t *f, struct vt_font **ret)
{
        size_t glyphsize, mapsize;
        struct vt_font *vf;
        int error;
        unsigned int i;

        /* Make sure the dimensions are valid. */
        if (f->width < 1 || f->height < 1)
                return (EINVAL);
        if (f->width > VTFONT_MAXDIMENSION || f->height > VTFONT_MAXDIMENSION ||
            f->glyph_count > VTFONT_MAXGLYPHS)
                return (E2BIG);

        /* Not too many mappings. */
        for (i = 0; i < VFNT_MAPS; i++)
                if (f->map_count[i] > VTFONT_MAXMAPPINGS)
                        return (E2BIG);

        /* Character 0 must always be present. */
        if (f->glyph_count < 1)
                return (EINVAL);

        glyphsize = howmany(f->width, 8) * f->height * f->glyph_count;
        if (glyphsize > VTFONT_MAXGLYPHSIZE)
                return (E2BIG);

        /* Allocate new font structure. */
        vf = malloc(sizeof *vf, M_VTFONT, M_WAITOK | M_ZERO);
        vf->vf_bytes = malloc(glyphsize, M_VTFONT, M_WAITOK);
        vf->vf_height = f->height;
        vf->vf_width = f->width;
        vf->vf_refcount = 1;

        /* Allocate, copy in, and validate mappings. */
        for (i = 0; i < VFNT_MAPS; i++) {
                vf->vf_map_count[i] = f->map_count[i];
                if (f->map_count[i] == 0)
                        continue;
                mapsize = f->map_count[i] * sizeof(vfnt_map_t);
                vf->vf_map[i] = malloc(mapsize, M_VTFONT, M_WAITOK);
                error = copyin(f->map[i], vf->vf_map[i], mapsize);
                if (error)
                        goto bad;
                error = vtfont_validate_map(vf->vf_map[i], vf->vf_map_count[i],
                    f->glyph_count);
                if (error)
                        goto bad;
        }

        /* Copy in glyph data. */
        error = copyin(f->glyphs, vf->vf_bytes, glyphsize);
        if (error)
                goto bad;

        /* Success. */
        *ret = vf;
        return (0);

bad:    vtfont_unref(vf);
        return (error);
}