/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 */

#pragma once

#include <font/TTFStructure.hxx>

#include <vcl/font/FontDataContainer.hxx>

#include <rtl/ustrbuf.hxx>

#include <sal/log.hxx>

namespace font

{

/** Handles reading of the name table */

class NameTableHandler

{

private:

    FontDataContainer const& mrFontDataContainer;

    const TableDirectoryEntry* mpTableDirectoryEntry;

    const char* mpNameTablePointer;

    const NameTable* mpNameTable;

    sal_uInt16 mnNumberOfRecords;

    const char* getTablePointer(const TableDirectoryEntry* pEntry, size_t nEntrySize)

    {

        size_t nSize = mrFontDataContainer.size();

        if (pEntry->offset > nSize)

        {

            SAL_WARN("vcl.fonts", "Table offset beyond end of available data");

            return nullptr;

        }

        if (nEntrySize > nSize - pEntry->offset)

        {

            SAL_WARN("vcl.fonts", "Insufficient available data for table entry");

            return nullptr;

        }

        return mrFontDataContainer.getPointer() + pEntry->offset;

    }

public:

    NameTableHandler(FontDataContainer const& rFontDataContainer,

                     const TableDirectoryEntry* pTableDirectoryEntry)

        : mrFontDataContainer(rFontDataContainer)

        , mpTableDirectoryEntry(pTableDirectoryEntry)

        , mpNameTablePointer(getTablePointer(mpTableDirectoryEntry, sizeof(NameTable)))

        , mpNameTable(reinterpret_cast<const NameTable*>(mpNameTablePointer))

        , mnNumberOfRecords(0)

    {

        if (mpNameTable)

        {

            mnNumberOfRecords = mpNameTable->nCount;

            const char* pEnd = mrFontDataContainer.getPointer() + mrFontDataContainer.size();

            const char* pStart = mpNameTablePointer + sizeof(NameTable);

            size_t nAvailableData = pEnd - pStart;

            size_t nMaxRecordsPossible = nAvailableData / sizeof(NameRecord);

            if (mnNumberOfRecords > nMaxRecordsPossible)

            {

                SAL_WARN("vcl.fonts", "Font claimed to have "

                                          << mnNumberOfRecords

                                          << " name records, but only space for "

                                          << nMaxRecordsPossible);

                mnNumberOfRecords = nMaxRecordsPossible;

            }

        }

    }

    sal_uInt32 getTableOffset() { return mpTableDirectoryEntry->offset; }

    const NameTable* getNameTable() { return mpNameTable; }

    /** Number of tables */

    sal_uInt16 getNumberOfRecords() { return mnNumberOfRecords; }

    /** Get a name table record for index */

    const NameRecord* getNameRecord(sal_uInt32 index)

    {

        const char* pPointer = mpNameTablePointer + sizeof(NameTable);

        pPointer += sizeof(NameRecord) * index;

        return reinterpret_cast<const NameRecord*>(pPointer);

    }

    /** Get offset to english unicode string

     *

     * See: https://learn.microsoft.com/en-us/typography/opentype/spec/name#name-ids

     */

    bool findEnglishUnicodeNameOffset(font::NameID eNameID, sal_uInt64& rOffset,

                                      sal_uInt16& rLength)

    {

        rOffset = 0;

        rLength = 0;

        for (sal_uInt16 n = 0, nCount = getNumberOfRecords(); n < nCount; n++)

        {

            const font::NameRecord* pNameRecord = getNameRecord(n);

            if (pNameRecord->nPlatformID == 3 // Windows

                && pNameRecord->nEncodingID == 1 // Unicode BMP

                && pNameRecord->nLanguageID == 0x0409 // en-us

                && pNameRecord->nNameID == sal_uInt16(eNameID))

            {

                rLength = pNameRecord->nLength;

                rOffset = getTableOffset() + getNameTable()->nStorageOffset

                          + pNameRecord->nStringOffset;

                return true;

            }

        }

        return false;

    }

};

/** Handles reading of table entries */

class TableEntriesHandler

{

private:

    FontDataContainer const& mrFontDataContainer;

    const char* mpFirstPosition;

    sal_uInt16 mnNumberOfTables;

    const char* getTablePointer(const TableDirectoryEntry* pEntry, size_t nEntrySize)

    {

        size_t nSize = mrFontDataContainer.size();

        if (pEntry->offset > nSize)

        {

            SAL_WARN("vcl.fonts", "Table offset beyond end of available data");

            return nullptr;

        }

        if (nEntrySize > nSize - pEntry->offset)

        {

            SAL_WARN("vcl.fonts", "Insufficient available data for table entry");

            return nullptr;

        }

        return mrFontDataContainer.getPointer() + pEntry->offset;

    }

public:

    TableEntriesHandler(FontDataContainer const& rFontDataContainer)

        : mrFontDataContainer(rFontDataContainer)

    {

        const char* pData = mrFontDataContainer.getPointer();

        assert(mrFontDataContainer.size() >= sizeof(TableDirectory));

        mpFirstPosition = pData + sizeof(TableDirectory);

        const TableDirectory* pDirectory = reinterpret_cast<const TableDirectory*>(pData);

        mnNumberOfTables = pDirectory->nNumberOfTables;

        size_t nAvailableData = mrFontDataContainer.size() - sizeof(TableDirectory);

        size_t nMaxRecordsPossible = nAvailableData / sizeof(TableDirectoryEntry);

        if (mnNumberOfTables > nMaxRecordsPossible)

        {

            SAL_WARN("vcl.fonts", "Font claimed to have " << mnNumberOfTables

                                                          << " table records, but only space for "

                                                          << nMaxRecordsPossible);

            mnNumberOfTables = nMaxRecordsPossible;

        }

    }

    const TableDirectoryEntry* getEntry(sal_uInt32 nTag)

    {

        for (sal_uInt32 i = 0; i < mnNumberOfTables; i++)

        {

            const char* pPosition = mpFirstPosition + sizeof(TableDirectoryEntry) * i;

            const auto* pEntry = reinterpret_cast<const TableDirectoryEntry*>(pPosition);

            if (nTag == pEntry->tag)

                return pEntry;

        }

        return nullptr;

    }

    const OS2Table* getOS2Table()

    {

        const auto* pEntry = getEntry(T_OS2);

        if (!pEntry)

            return nullptr;

        return reinterpret_cast<const OS2Table*>(getTablePointer(pEntry, sizeof(OS2Table)));

    }

    const HeadTable* getHeadTable()

    {

        const auto* pEntry = getEntry(T_head);

        if (!pEntry)

            return nullptr;

        return reinterpret_cast<const HeadTable*>(getTablePointer(pEntry, sizeof(HeadTable)));

    }

    const NameTable* getNameTable()

    {

        const auto* pEntry = getEntry(T_name);

        if (!pEntry)

            return nullptr;

        return reinterpret_cast<const NameTable*>(getTablePointer(pEntry, sizeof(NameTable)));

    }

    std::unique_ptr<NameTableHandler> getNameTableHandler()

    {

        const auto* pEntry = getEntry(T_name);

        if (!pEntry)

            return nullptr;

        return std::unique_ptr<NameTableHandler>(new NameTableHandler(mrFontDataContainer, pEntry));

    }

};

/** Entry point handler for the TTF Font */

class TTFFont

{

private:

    FontDataContainer const& mrFontDataContainer;

public:

    TTFFont(FontDataContainer const& rFontDataContainer)

        : mrFontDataContainer(rFontDataContainer)

    {

    }

    std::unique_ptr<TableEntriesHandler> getTableEntriesHandler()

    {

        size_t nSize = mrFontDataContainer.size();

        if (nSize < sizeof(TableDirectory))

        {

            SAL_WARN("vcl.fonts", "Font Data shorter than a TableDirectory");

            return nullptr;

        }

        return std::make_unique<TableEntriesHandler>(mrFontDataContainer);

    }

    /** Gets the string from a name table */

    OUString getNameTableString(sal_uInt64 nOffset, sal_uInt16 nLength)

    {

        size_t nSize = mrFontDataContainer.size();

        if (nOffset > nSize)

        {

            SAL_WARN("vcl.fonts", "String offset beyond end of available data");

            return OUString();

        }

        if (nLength > nSize - nOffset)

        {

            SAL_WARN("vcl.fonts", "Insufficient available data for string entry");

            return OUString();

        }

        const auto* pString = reinterpret_cast<const o3tl::sal_uInt16_BE*>(

            mrFontDataContainer.getPointer() + nOffset);

        OUStringBuffer aStringBuffer;

        for (sal_uInt16 i = 0; i < (nLength / 2); i++)

            aStringBuffer.append(sal_Unicode(pString[i]));

        return aStringBuffer.makeStringAndClear();

    }

};

}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */