iTextSharp.text.Jpeg.ProcessParameters C# (CSharp) Method

ProcessParameters() private method

This method checks if the image is a valid JPEG and processes some parameters.
private ProcessParameters ( ) : void
return void
        private void ProcessParameters()
        {
            type = Element.JPEG;
            originalType = ORIGINAL_JPEG;
            Stream istr = null;
            try {
                string errorID;
                if (rawData == null){
                    WebRequest w = WebRequest.Create(url);
                    w.Credentials = CredentialCache.DefaultCredentials;
                    istr = w.GetResponse().GetResponseStream();
                    errorID = url.ToString();
                }
                else{
                    istr = new MemoryStream(rawData);
                    errorID = "Byte array";
                }
                if (istr.ReadByte() != 0xFF || istr.ReadByte() != 0xD8)    {
                    throw new BadElementException(MessageLocalization.GetComposedMessage("1.is.not.a.valid.jpeg.file", errorID));
                }
                bool firstPass = true;
                int len;
                while (true) {
                    int v = istr.ReadByte();
                    if (v < 0)
                        throw new IOException(MessageLocalization.GetComposedMessage("premature.eof.while.reading.jpg"));
                    if (v == 0xFF) {
                        int marker = istr.ReadByte();
                        if (firstPass && marker == M_APP0) {
                            firstPass = false;
                            len = GetShort(istr);
                            if (len < 16) {
                                Utilities.Skip(istr, len - 2);
                                continue;
                            }
                            byte[] bcomp = new byte[JFIF_ID.Length];
                            int r = istr.Read(bcomp, 0, bcomp.Length);
                            if (r != bcomp.Length)
                                throw new BadElementException(MessageLocalization.GetComposedMessage("1.corrupted.jfif.marker", errorID));
                            bool found = true;
                            for (int k = 0; k < bcomp.Length; ++k) {
                                if (bcomp[k] != JFIF_ID[k]) {
                                    found = false;
                                    break;
                                }
                            }
                            if (!found) {
                                Utilities.Skip(istr, len - 2 - bcomp.Length);
                                continue;
                            }
                            Utilities.Skip(istr, 2);
                            int units = istr.ReadByte();
                            int dx = GetShort(istr);
                            int dy = GetShort(istr);
                            if (units == 1) {
                                dpiX = dx;
                                dpiY = dy;
                            }
                            else if (units == 2) {
                                dpiX = (int)((float)dx * 2.54f + 0.5f);
                                dpiY = (int)((float)dy * 2.54f + 0.5f);
                            }
                            Utilities.Skip(istr, len - 2 - bcomp.Length - 7);
                            continue;
                        }
                        if (marker == M_APPE) {
                            len = GetShort(istr) - 2;
                            byte[] byteappe = new byte[len];
                            for (int k = 0; k < len; ++k) {
                                byteappe[k] = (byte)istr.ReadByte();
                            }
                            if (byteappe.Length >= 12) {
                                string appe = System.Text.ASCIIEncoding.ASCII.GetString(byteappe,0,5);
                                if (Util.EqualsIgnoreCase(appe, "adobe")) {
                                    invert = true;
                                }
                            }
                            continue;
                        }
                        if (marker == M_APP2) {
                            len = GetShort(istr) - 2;
                            byte[] byteapp2 = new byte[len];
                            for (int k = 0; k < len; ++k) {
                                byteapp2[k] = (byte)istr.ReadByte();
                            }
                            if (byteapp2.Length >= 14) {
                                String app2 = System.Text.ASCIIEncoding.ASCII.GetString(byteapp2, 0, 11);
                                if (app2.Equals("ICC_PROFILE")) {
                                    int order = byteapp2[12] & 0xff;
                                    int count = byteapp2[13] & 0xff;
                                    // some jpeg producers don't know how to count to 1
                                    if (order < 1)
                                        order = 1;
                                    if (count < 1)
                                        count = 1;
                                    if (icc == null)
                                        icc = new byte[count][];
                                    icc[order - 1] = byteapp2;
                                }
                            }
                            continue;
                        }
                        if (marker == M_APPD) {
                            len = GetShort(istr) - 2;
                            byte[] byteappd = new byte[len];
                            for (int k = 0; k < len; k++) {
                                byteappd[k] = (byte)istr.ReadByte();
                            }
                            // search for '8BIM Resolution' marker
                            int j = 0;
                            for (j = 0; j < len-PS_8BIM_RESO.Length; j++) {
                                bool found = true;
                                for (int i = 0; i < PS_8BIM_RESO.Length; i++) {
                                    if (byteappd[j+i] != PS_8BIM_RESO[i]) {
                                        found = false;
                                        break;
                                    }
                                }
                                if (found)
                                    break;
                            }

                            j+=PS_8BIM_RESO.Length;
                            if (j < len-PS_8BIM_RESO.Length) {
                                // "PASCAL String" for name, i.e. string prefix with length byte
                                // padded to be even length; 2 null bytes if empty
                                byte namelength = byteappd[j];
                                // add length byte
                                namelength++;
                                // add padding
                                if (namelength % 2 == 1)
                                    namelength++;
                                // just skip name
                                j += namelength;
                                // size of the resolution data
                                int resosize = (byteappd[j] << 24) + (byteappd[j+1] << 16) + (byteappd[j+2] << 8) + byteappd[j+3];
                                // should be 16
                                if (resosize != 16) {
                                    // fail silently, for now
                                    //System.err.println("DEBUG: unsupported resolution IRB size");
                                    continue;
                                }
                                j+=4;
                                int dx = (byteappd[j] << 8) + (byteappd[j+1] & 0xff);
                                j+=2;
                                // skip 2 unknown bytes
                                j+=2;
                                int unitsx = (byteappd[j] << 8) + (byteappd[j + 1] & 0xff);
                                j+=2;
                                // skip 2 unknown bytes
                                j+=2;
                                int dy = (byteappd[j] << 8) + (byteappd[j + 1] & 0xff);
                                j+=2;
                                // skip 2 unknown bytes
                                j+=2;
                                int unitsy = (byteappd[j] << 8) + (byteappd[j + 1] & 0xff);

                                if (unitsx == 1 || unitsx == 2) {
                                    dx = (unitsx == 2 ? (int)(dx * 2.54f + 0.5f) : dx);
                                    // make sure this is consistent with JFIF data
                                    if (dpiX != 0 && dpiX != dx) {
                                        //System.err.println("DEBUG: inconsistent metadata (dpiX: " + dpiX + " vs " + dx + ")");
                                    }
                                    else
                                        dpiX = dx;
                                }
                                if (unitsy == 1 || unitsy == 2) {
                                    dy = (unitsy == 2 ? (int)(dy * 2.54f + 0.5f) : dy);
                                    // make sure this is consistent with JFIF data
                                    if (dpiY != 0 && dpiY != dy) {
                                        //System.err.println("DEBUG: inconsistent metadata (dpiY: " + dpiY + " vs " + dy + ")");
                                    }
                                    else
                                        dpiY = dy;
                                }
                            }
                            continue;
                        }
                        firstPass = false;
                        int markertype = MarkerType(marker);
                        if (markertype == VALID_MARKER) {
                            Utilities.Skip(istr, 2);
                            if (istr.ReadByte() != 0x08) {
                                throw new BadElementException(MessageLocalization.GetComposedMessage("1.must.have.8.bits.per.component", errorID));
                            }
                            scaledHeight = GetShort(istr);
                            Top = scaledHeight;
                            scaledWidth = GetShort(istr);
                            Right = scaledWidth;
                             colorspace = istr.ReadByte();
                            bpc = 8;
                            break;
                        }
                        else if (markertype == UNSUPPORTED_MARKER) {
                            throw new BadElementException(MessageLocalization.GetComposedMessage("1.unsupported.jpeg.marker.2", errorID, marker));
                        }
                        else if (markertype != NOPARAM_MARKER) {
                            Utilities.Skip(istr, GetShort(istr) - 2);
                        }
                    }
                }
            }
            finally {
                if (istr != null) {
                    istr.Close();
                }
            }
            plainWidth = this.Width;
            plainHeight = this.Height;
            if (icc != null) {
                int total = 0;
                for (int k = 0; k < icc.Length; ++k) {
                    if (icc[k] == null) {
                        icc = null;
                        return;
                    }
                    total += icc[k].Length - 14;
                }
                byte[] ficc = new byte[total];
                total = 0;
                for (int k = 0; k < icc.Length; ++k) {
                    System.Array.Copy(icc[k], 14, ficc, total, icc[k].Length - 14);
                    total += icc[k].Length - 14;
                }
                try {
                    ICC_Profile icc_prof = ICC_Profile.GetInstance(ficc, colorspace);
                    TagICC = icc_prof;
                }
                catch {}
                icc = null;
            }
        }