dlls/dwrite/opentype.c

/*
 *    Methods for dealing with opentype font tables
 *
 * Copyright 2014 Aric Stewart for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#define COBJMACROS

#include "dwrite.h"
#include "dwrite_private.h"

WINE_DEFAULT_DEBUG_CHANNEL(dwrite);

#define DWRITE_MAKE_OPENTYPE_TAG(ch0, ch1, ch2, ch3) \
                    ((DWORD)(BYTE)(ch0) | ((DWORD)(BYTE)(ch1) << 8) | \
                    ((DWORD)(BYTE)(ch2) << 16) | ((DWORD)(BYTE)(ch3) << 24))

#define MS_TTCF_TAG DWRITE_MAKE_OPENTYPE_TAG('t','t','c','f')
#define MS_OTTO_TAG DWRITE_MAKE_OPENTYPE_TAG('O','T','T','O')

#ifdef WORDS_BIGENDIAN
#define GET_BE_WORD(x) (x)
#define GET_BE_DWORD(x) (x)
#else
#define GET_BE_WORD(x) MAKEWORD(HIBYTE(x), LOBYTE(x))
#define GET_BE_DWORD(x) MAKELONG(GET_BE_WORD(HIWORD(x)), GET_BE_WORD(LOWORD(x)))
#endif

typedef struct {
    CHAR TTCTag[4];
    DWORD Version;
    DWORD numFonts;
    DWORD OffsetTable[1];
} TTC_Header_V1;

typedef struct {
    DWORD version;
    WORD numTables;
    WORD searchRange;
    WORD entrySelector;
    WORD rangeShift;
} TTC_SFNT_V1;

typedef struct {
    CHAR tag[4];
    DWORD checkSum;
    DWORD offset;
    DWORD length;
} TT_TableRecord;

HRESULT analyze_opentype_font(const void* font_data, UINT32* font_count, DWRITE_FONT_FILE_TYPE *file_type, DWRITE_FONT_FACE_TYPE *face_type, BOOL *supported)
{
    /* TODO: Do font validation */
    const char* tag = font_data;

    *supported = FALSE;
    *file_type = DWRITE_FONT_FILE_TYPE_UNKNOWN;
    if (face_type)
        *face_type = DWRITE_FONT_FACE_TYPE_UNKNOWN;
    *font_count = 0;

    if (DWRITE_MAKE_OPENTYPE_TAG(tag[0], tag[1], tag[2], tag[3]) == MS_TTCF_TAG)
    {
        const TTC_Header_V1 *header = font_data;
        *font_count = GET_BE_DWORD(header->numFonts);
        *file_type = DWRITE_FONT_FILE_TYPE_TRUETYPE_COLLECTION;
        if (face_type)
            *face_type = DWRITE_FONT_FACE_TYPE_TRUETYPE_COLLECTION;
        *supported = TRUE;
    }
    else if (GET_BE_DWORD(*(DWORD*)font_data) == 0x10000)
    {
        *font_count = 1;
        *file_type = DWRITE_FONT_FILE_TYPE_TRUETYPE;
        if (face_type)
            *face_type = DWRITE_FONT_FACE_TYPE_TRUETYPE;
        *supported = TRUE;
    }
    else if (DWRITE_MAKE_OPENTYPE_TAG(tag[0], tag[1], tag[2], tag[3]) == MS_OTTO_TAG)
    {
        *file_type = DWRITE_FONT_FILE_TYPE_CFF;
    }
    return S_OK;
}

HRESULT find_font_table(IDWriteFontFileStream *stream, UINT32 font_index, UINT32 tag, const void** table_data, void** table_context, UINT32 *table_size, BOOL* found)
{
    const CHAR *first_data;
    void *first_context;
    HRESULT hr;
    TTC_SFNT_V1 *font_header = NULL;
    void *sfnt_context;
    TT_TableRecord *table_record = NULL;
    void *table_record_context;
    int i;
    int table_count;
    int table_offset = 0;

    *found = FALSE;

    hr = IDWriteFontFileStream_ReadFileFragment(stream, (const void**)&first_data, 0, 4, &first_context);
    if (SUCCEEDED(hr))
    {
        if (DWRITE_MAKE_OPENTYPE_TAG(first_data[0], first_data[1], first_data[2], first_data[3]) == MS_TTCF_TAG)
        {
            const TTC_Header_V1 *ttc_header;
            void * ttc_context;
            hr = IDWriteFontFileStream_ReadFileFragment(stream, (const void**)&ttc_header, 0, sizeof(*ttc_header), &ttc_context);
            if (SUCCEEDED(hr))
            {
                table_offset = GET_BE_DWORD(ttc_header->OffsetTable[0]);
                if (font_index >= GET_BE_DWORD(ttc_header->numFonts))
                    hr = E_INVALIDARG;
                else
                    hr = IDWriteFontFileStream_ReadFileFragment(stream, (const void**)&font_header, table_offset, sizeof(*font_header), &sfnt_context);
                IDWriteFontFileStream_ReleaseFileFragment(stream, ttc_context);
            }
        }
        else
        {
            if (font_index > 0)
                hr = E_INVALIDARG;
            else
                hr = IDWriteFontFileStream_ReadFileFragment(stream, (const void**)&font_header, 0, sizeof(*font_header), &sfnt_context);
        }
        IDWriteFontFileStream_ReleaseFileFragment(stream, first_context);
    }
    if (FAILED(hr))
        return hr;

    table_count = GET_BE_WORD(font_header->numTables);
    table_offset += sizeof(*font_header);
    for (i = 0; i < table_count; i++)
    {
        hr = IDWriteFontFileStream_ReadFileFragment(stream, (const void**)&table_record, table_offset, sizeof(*table_record), &table_record_context);
        if (FAILED(hr))
            break;
        if (DWRITE_MAKE_OPENTYPE_TAG(table_record->tag[0], table_record->tag[1], table_record->tag[2], table_record->tag[3]) == tag)
            break;
        IDWriteFontFileStream_ReleaseFileFragment(stream, table_record_context);
        table_offset += sizeof(*table_record);
    }

    IDWriteFontFileStream_ReleaseFileFragment(stream, sfnt_context);
    if (SUCCEEDED(hr) && i < table_count)
    {
        int offset = GET_BE_DWORD(table_record->offset);
        int length = GET_BE_DWORD(table_record->length);
        IDWriteFontFileStream_ReleaseFileFragment(stream, table_record_context);

        *found = TRUE;
        *table_size = length;
        hr = IDWriteFontFileStream_ReadFileFragment(stream, table_data, offset, length, table_context);
    }

    return hr;
}