//========================================================================

//

// FoFiBase.cc

//

// Copyright 1999-2003 Glyph & Cog, LLC

//

//========================================================================

//========================================================================

//

// Modified under the Poppler project - http://poppler.freedesktop.org

//

// All changes made under the Poppler project to this file are licensed

// under GPL version 2 or later

//

// Copyright (C) 2008 Ed Avis <eda@waniasset.com>

// Copyright (C) 2011 Jim Meyering <jim@meyering.net>

// Copyright (C) 2016, 2018, 2020, 2026 Albert Astals Cid <aacid@kde.org>

// Copyright (C) 2019 Christian Persch <chpe@src.gnome.org>

// Copyright (C) 2019 LE GARREC Vincent <legarrec.vincent@gmail.com>

// Copyright (C) 2022 Oliver Sander <oliver.sander@tu-dresden.de>

// Copyright (C) 2025, 2026 g10 Code GmbH, Author: Sune Stolborg Vuorela <sune@vuorela.dk>

//

// To see a description of the changes please see the Changelog file that

// came with your tarball or type make ChangeLog if you are building from git

//

//========================================================================

#include <config.h>

#include <cstdio>

#include <climits>

#include "goo/gfile.h"

#include "poppler/Error.h"

#include "FoFiBase.h"

//------------------------------------------------------------------------

// FoFiBase

//------------------------------------------------------------------------

FoFiBase::FoFiBase(std::vector<unsigned char> &&fileA) : fileOwner(std::move(fileA)), file(fileOwner) { }

FoFiBase::FoFiBase(std::span<const unsigned char> fileA) : file(fileA) { }

FoFiBase::~FoFiBase() = default;

std::optional<std::vector<unsigned char>> FoFiBase::readFile(const char *fileName)

{

    FILE *f;

    if (!(f = openFile(fileName, "rb"))) {

        error(errIO, -1, "Cannot open '{0:s}'", fileName);

        return std::nullopt;

    }

    if (fseek(f, 0, SEEK_END) != 0) {

        error(errIO, -1, "Cannot seek to end of '{0:s}'", fileName);

        fclose(f);

        return std::nullopt;

    }

    const int n = static_cast<int>(ftell(f));

    if (n < 0) {

        error(errIO, -1, "Cannot determine length of '{0:s}'", fileName);

        fclose(f);

        return std::nullopt;

    }

    if (fseek(f, 0, SEEK_SET) != 0) {

        error(errIO, -1, "Cannot seek to start of '{0:s}'", fileName);

        fclose(f);

        return std::nullopt;

    }

    const size_t nToRead = n;

    std::vector<unsigned char> buf;

    buf.resize(nToRead);

    if (fread(buf.data(), 1, nToRead, f) != nToRead) {

        fclose(f);

        return std::nullopt;

    }

    fclose(f);

    return buf;

}

int FoFiBase::getS8(int pos, bool *ok) const

{

    int x;

    if (pos < 0 || static_cast<size_t>(pos) >= file.size()) {

        *ok = false;

        return 0;

    }

    x = file[pos];

    if (x & 0x80) {

        x |= ~0xff;

    }

    return x;

}

int FoFiBase::getU8(int pos, bool *ok) const

{

    if (pos < 0 || static_cast<size_t>(pos) >= file.size()) {

        *ok = false;

        return 0;

    }

    return file[pos];

}

int FoFiBase::getS16BE(int pos, bool *ok) const

{

    int x;

    if (pos < 0 || pos > INT_MAX - 1 || pos + 1 >= static_cast<int>(file.size())) {

        *ok = false;

        return 0;

    }

    x = file[pos];

    x = (x << 8) + file[pos + 1];

    if (x & 0x8000) {

        x |= ~0xffff;

    }

    return x;

}

int FoFiBase::getU16BE(int pos, bool *ok) const

{

    int x;

    if (pos < 0 || pos > INT_MAX - 1 || pos + 1 >= static_cast<int>(file.size())) {

        *ok = false;

        return 0;

    }

    x = file[pos];

    x = (x << 8) + file[pos + 1];

    return x;

}

int FoFiBase::getS32BE(int pos, bool *ok) const

{

    int x;

    if (pos < 0 || pos > INT_MAX - 3 || pos + 3 >= static_cast<int>(file.size())) {

        *ok = false;

        return 0;

    }

    x = file[pos];

    x = (x << 8) + file[pos + 1];

    x = (x << 8) + file[pos + 2];

    x = (x << 8) + file[pos + 3];

    if (x & 0x80000000) {

        x |= ~0xffffffff;

    }

    return x;

}

unsigned int FoFiBase::getU32BE(int pos, bool *ok) const

{

    unsigned int x;

    if (pos < 0 || pos > INT_MAX - 3 || pos + 3 >= static_cast<int>(file.size())) {

        *ok = false;

        return 0;

    }

    x = file[pos];

    x = (x << 8) + file[pos + 1];

    x = (x << 8) + file[pos + 2];

    x = (x << 8) + file[pos + 3];

    return x;

}

unsigned int FoFiBase::getU32LE(int pos, bool *ok) const

{

    unsigned int x;

    if (pos < 0 || pos > INT_MAX - 3 || pos + 3 >= static_cast<int>(file.size())) {

        *ok = false;

        return 0;

    }

    x = file[pos + 3];

    x = (x << 8) + file[pos + 2];

    x = (x << 8) + file[pos + 1];

    x = (x << 8) + file[pos];

    return x;

}

unsigned int FoFiBase::getUVarBE(int pos, int size, bool *ok) const

{

    unsigned int x;

    int i;

    if (pos < 0 || pos > INT_MAX - size || pos + size > static_cast<int>(file.size())) {

        *ok = false;

        return 0;

    }

    x = 0;

    for (i = 0; i < size; ++i) {

        x = (x << 8) + file[pos + i];

    }

    return x;

}

bool FoFiBase::checkRegion(int pos, int size) const

{

    return pos >= 0 && size >= 0 && pos < INT_MAX - size && size < INT_MAX - pos && pos + size >= pos && pos + size <= static_cast<int>(file.size());

}