// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; c-brace-offset: 0; -*-
/*
 * SPDX-FileCopyrightText: 1994 Paul Vojta. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <config.h>

#include "debug_dvi.h"
#include "dvi.h"
#include "dviRenderer.h"
#include "xdvi.h"

#include <KLocalizedString>

#include <cstdlib>
#include <cstring>

extern void oops(const QString &message);

/***
 ***   VF font reading routines.
 ***   Public routine is read_index---because virtual characters are presumed
 ***   to be short, we read the whole virtual font in at once, instead of
 ***   faulting in characters as needed.
 ***/

#define LONG_CHAR 242

/*
 *  These are parameters which determine whether macros are combined for
 *  storage allocation purposes.  Small macros ( <= VF_PARM_1 bytes) are
 *  combined into chunks of size VF_PARM_2.
 */

#ifndef VF_PARM_1
#define VF_PARM_1 20
#endif
#ifndef VF_PARM_2
#define VF_PARM_2 256
#endif

/*
 *  The main routine
 */

void TeXFontDefinition::read_VF_index()
{
#ifdef DEBUG_FONTS
    qCDebug(OkularDviDebug) << "font::read_VF_index()";
#endif
    FILE *VF_file = file;
    unsigned char cmnd;
    // available space for macros
    unsigned char *avail, *availend;

    flags |= FONT_VIRTUAL;
    set_char_p = &dviRenderer::set_vf_char;
#ifdef DEBUG_FONTS
    qCDebug(OkularDviDebug) << "TeXFontDefinition::read_VF_index: reading VF pixel file " << filename;
#endif
    // Read preamble.
    fseek(VF_file, (long)one(VF_file), 1); /* skip comment */
    quint32 const file_checksum = four(VF_file);

    if (file_checksum && checksum && file_checksum != checksum)
        qCCritical(OkularDviDebug) << "Checksum mismatch dvi = " << checksum << "u, vf = " << file_checksum << "u) in font file" << filename << endl;
    (void)four(VF_file); /* skip design size */

    // Read the fonts.
    first_font = nullptr;
    while ((cmnd = one(VF_file)) >= FNTDEF1 && cmnd <= FNTDEF4) {
        int TeXnumber = num(VF_file, (int)cmnd - FNTDEF1 + 1);
        quint32 checksum = four(VF_file);
        quint32 scale = four(VF_file);
        quint32 design = four(VF_file);
        Q_UNUSED(design);
        quint16 len = one(VF_file) + one(VF_file); /* sequence point in the middle */
        char *fontname = new char[len + 1];
        fread(fontname, sizeof(char), len, VF_file);
        fontname[len] = '\0';

#ifdef DEBUG_FONTS
        qCDebug(OkularDviDebug) << "Virtual font defines subfont \"" << fontname << "\" scale=" << scale << " design=" << design;
#endif

        // According to Knuth's documentation found in the web source code
        // of the "vftovp" program (which seems to be the standard
        // definition of virtual fonts), the "scale" is a fixed point
        // number which describes extra enlargement that the virtual font
        // imposes. One obtains the enlargement by dividing 2^20.
        double enlargement_factor = double(scale) / (1 << 20) * enlargement;

        //    TeXFontDefinition *newfontp = font_pool->appendx(fontname, checksum, (quint32)(scaled_size_in_DVI_units*enlargement_factor), enlargement_factor);
        TeXFontDefinition *newfontp = font_pool->appendx(QString::fromLocal8Bit(fontname), checksum, (quint32)((double(scale) / (1 << 20)) * scaled_size_in_DVI_units), enlargement_factor);

        // Insert font in dictionary and make sure the dictionary is big
        // enough.
        if (vf_table.capacity() - 2 <= vf_table.count())
            // Not quite optimal. The size of the dictionary should be a
            // prime. I don't care.
            vf_table.reserve(vf_table.capacity() * 2);
        vf_table.insert(TeXnumber, newfontp);

        if (first_font == nullptr)
            first_font = newfontp;
    }

    // Prepare macro array.
    macrotable = new macro[max_num_of_chars_in_font];
    if (macrotable == nullptr) {
        qCCritical(OkularDviDebug) << "Could not allocate memory for a macro table.";
        exit(0);
    }

    // Read macros.
    avail = availend = nullptr;
    for (; cmnd <= LONG_CHAR; cmnd = one(VF_file)) {
        macro *m;
        int len;
        unsigned long cc;
        long width;

        if (cmnd == LONG_CHAR) { /* long form packet */
            len = four(VF_file);
            cc = four(VF_file);
            width = four(VF_file);
            if (cc >= 256) {
                qCCritical(OkularDviDebug) << "Virtual character" << cc << "in font" << fontname << "ignored.";
                fseek(VF_file, (long)len, 1);
                continue;
            }
        } else { /* short form packet */
            len = cmnd;
            cc = one(VF_file);
            width = num(VF_file, 3);
        }
        m = &macrotable[cc];

        m->dvi_advance_in_units_of_design_size_by_2e20 = width;
        if (len > 0) {
            if (len <= availend - avail) {
                m->pos = avail;
                avail += len;
            } else {
                m->free_me = true;
                if (len <= VF_PARM_1) {
                    m->pos = avail = new unsigned char[VF_PARM_2];
                    availend = avail + VF_PARM_2;
                    avail += len;
                } else
                    m->pos = new unsigned char[len];
            }
            fread((char *)m->pos, 1, len, VF_file);
            m->end = m->pos + len;
        }
    }
    if (cmnd != POST)
        oops(i18n("Wrong command byte found in VF macro list: %1", cmnd));

    fclose(VF_file);
    file = nullptr;
}
