BitMiracle.LibTiff.Classic.Tiff.ReadCustomDirectory C# (CSharp) Method

        public bool ReadCustomDirectory(long offset, TiffFieldInfo[] info, int count)
        {
            const string module = "ReadCustomDirectory";

            setupFieldInfo(info, count);

            uint dummyNextDirOff;
            TiffDirEntry[] dir;
            short dircount = fetchDirectory((uint)offset, out dir, out dummyNextDirOff);
            if (dircount == 0)
            {
                ErrorExt(this, m_clientdata, module,
                    "{0}: Failed to read custom directory at offset {1}", m_name, offset);
                return false;
            }

            FreeDirectory();
            m_dir = new TiffDirectory();

            int fix = 0;
            for (short i = 0; i < dircount; i++)
            {
                if ((m_flags & TiffFlags.SWAB) == TiffFlags.SWAB)
                {
                    short temp = (short)dir[i].tdir_tag;
                    SwabShort(ref temp);
                    dir[i].tdir_tag = (TiffTag)(ushort)temp;

                    temp = (short)dir[i].tdir_type;
                    SwabShort(ref temp);
                    dir[i].tdir_type = (TiffType)temp;

                    SwabLong(ref dir[i].tdir_count);
                    SwabUInt(ref dir[i].tdir_offset);
                }

                if (fix >= m_nfields || dir[i].tdir_tag == TiffTag.IGNORE)
                    continue;

                while (fix < m_nfields && m_fieldinfo[fix].Tag < dir[i].tdir_tag)
                    fix++;

                if (fix >= m_nfields || m_fieldinfo[fix].Tag != dir[i].tdir_tag)
                {
                    WarningExt(this, m_clientdata, module,
                        "{0}: unknown field with tag {1} (0x{2:x}) encountered",
                        m_name, (ushort)dir[i].tdir_tag, (ushort)dir[i].tdir_tag);

                    TiffFieldInfo[] arr = new TiffFieldInfo[1];
                    arr[0] = createAnonFieldInfo(dir[i].tdir_tag, dir[i].tdir_type);
                    MergeFieldInfo(arr, 1);

                    fix = 0;
                    while (fix < m_nfields && m_fieldinfo[fix].Tag < dir[i].tdir_tag)
                        fix++;
                }

                // null out old tags that we ignore.
                if (m_fieldinfo[fix].Bit == FieldBit.Ignore)
                {
                    dir[i].tdir_tag = TiffTag.IGNORE;
                    continue;
                }

                // Check data type.
                TiffFieldInfo fip = m_fieldinfo[fix];
                while (dir[i].tdir_type != fip.Type && fix < m_nfields)
                {
                    if (fip.Type == TiffType.ANY)
                    {
                        // wildcard
                        break;
                    }

                    fip = m_fieldinfo[++fix];
                    if (fix >= m_nfields || fip.Tag != dir[i].tdir_tag)
                    {
                        WarningExt(this, m_clientdata, module,
                            "{0}: wrong data type {1} for \"{2}\"; tag ignored",
                            m_name, dir[i].tdir_type, m_fieldinfo[fix - 1].Name);

                        dir[i].tdir_tag = TiffTag.IGNORE;
                        continue;
                    }
                }

                // Check count if known in advance.
                if (fip.ReadCount != TiffFieldInfo.Variable &&
                    fip.ReadCount != TiffFieldInfo.Variable2)
                {
                    int expected = fip.ReadCount;
                    if (fip.ReadCount == TiffFieldInfo.Spp)
                        expected = m_dir.td_samplesperpixel;

                    if (!checkDirCount(dir[i], expected))
                    {
                        dir[i].tdir_tag = TiffTag.IGNORE;
                        continue;
                    }
                }

                // EXIF tags which need to be specifically processed.
                switch (dir[i].tdir_tag)
                {
                    case TiffTag.EXIF_SUBJECTDISTANCE:
                        fetchSubjectDistance(dir[i]);
                        break;
                    default:
                        fetchNormalTag(dir[i]);
                        break;
                }
            }

            return true;
        }