Beispiel #1
0
 private static Version chooseVersion(int numInputBits, ErrorCorrectionLevel ecLevel)
 {
     // In the following comments, we use numbers of Version 7-H.
     for (int versionNum = 1; versionNum <= 40; versionNum++)
     {
         Version version = Version.getVersionForNumber(versionNum);
         // numBytes = 196
         int numBytes = version.TotalCodewords;
         // getNumECBytes = 130
         Version.ECBlocks ecBlocks = version.getECBlocksForLevel(ecLevel);
         int numEcBytes            = ecBlocks.TotalECCodewords;
         // getNumDataBytes = 196 - 130 = 66
         int numDataBytes    = numBytes - numEcBytes;
         int totalInputBytes = (numInputBits + 7) / 8;
         if (numDataBytes >= totalInputBytes)
         {
             return(version);
         }
     }
     throw new WriterException("Data too big");
 }
Beispiel #2
0
        private static int chooseMaskPattern(BitArray bits,
                                             ErrorCorrectionLevel ecLevel,
                                             Version version,
                                             ByteMatrix matrix)
        {
            int minPenalty      = Int32.MaxValue; // Lower penalty is better.
            int bestMaskPattern = -1;

            // We try all mask patterns to choose the best one.
            for (int maskPattern = 0; maskPattern < QRCode.NUM_MASK_PATTERNS; maskPattern++)
            {
                MatrixUtil.buildMatrix(bits, ecLevel, version, maskPattern, matrix);
                int penalty = calculateMaskPenalty(matrix);
                if (penalty < minPenalty)
                {
                    minPenalty      = penalty;
                    bestMaskPattern = maskPattern;
                }
            }
            return(bestMaskPattern);
        }
        internal static DecoderResult decode(byte[] bytes,
                                             Version version,
                                             ErrorCorrectionLevel ecLevel,
                                             IDictionary <DecodeHintType, object> hints)
        {
            var bits         = new BitSource(bytes);
            var result       = new StringBuilder(50);
            var byteSegments = new List <byte[]>(1);

            try
            {
                CharacterSetECI currentCharacterSetECI = null;
                bool            fc1InEffect            = false;
                Mode            mode;
                do
                {
                    // While still another segment to read...
                    if (bits.available() < 4)
                    {
                        // OK, assume we're done. Really, a TERMINATOR mode should have been recorded here
                        mode = Mode.TERMINATOR;
                    }
                    else
                    {
                        try
                        {
                            mode = Mode.forBits(bits.readBits(4)); // mode is encoded by 4 bits
                        }
                        catch (ArgumentException)
                        {
                            return(null);
                        }
                    }
                    if (mode != Mode.TERMINATOR)
                    {
                        if (mode == Mode.FNC1_FIRST_POSITION || mode == Mode.FNC1_SECOND_POSITION)
                        {
                            // We do little with FNC1 except alter the parsed result a bit according to the spec
                            fc1InEffect = true;
                        }
                        else if (mode == Mode.STRUCTURED_APPEND)
                        {
                            if (bits.available() < 16)
                            {
                                return(null);
                            }
                            // not really supported; all we do is ignore it
                            // Read next 8 bits (symbol sequence #) and 8 bits (parity data), then continue
                            bits.readBits(16);
                        }
                        else if (mode == Mode.ECI)
                        {
                            // Count doesn't apply to ECI
                            int value = parseECIValue(bits);
                            currentCharacterSetECI = CharacterSetECI.getCharacterSetECIByValue(value);
                            if (currentCharacterSetECI == null)
                            {
                                return(null);
                            }
                        }
                        else
                        {
                            // First handle Hanzi mode which does not start with character count
                            if (mode == Mode.HANZI)
                            {
                                //chinese mode contains a sub set indicator right after mode indicator
                                int subset     = bits.readBits(4);
                                int countHanzi = bits.readBits(mode.getCharacterCountBits(version));
                                if (subset == GB2312_SUBSET)
                                {
                                    if (!decodeHanziSegment(bits, result, countHanzi))
                                    {
                                        return(null);
                                    }
                                }
                            }
                            else
                            {
                                // "Normal" QR code modes:
                                // How many characters will follow, encoded in this mode?
                                int count = bits.readBits(mode.getCharacterCountBits(version));
                                if (mode == Mode.NUMERIC)
                                {
                                    if (!decodeNumericSegment(bits, result, count))
                                    {
                                        return(null);
                                    }
                                }
                                else if (mode == Mode.ALPHANUMERIC)
                                {
                                    if (!decodeAlphanumericSegment(bits, result, count, fc1InEffect))
                                    {
                                        return(null);
                                    }
                                }
                                else if (mode == Mode.BYTE)
                                {
                                    if (!decodeByteSegment(bits, result, count, currentCharacterSetECI, byteSegments, hints))
                                    {
                                        return(null);
                                    }
                                }
                                else if (mode == Mode.KANJI)
                                {
                                    if (!decodeKanjiSegment(bits, result, count))
                                    {
                                        return(null);
                                    }
                                }
                                else
                                {
                                    return(null);
                                }
                            }
                        }
                    }
                } while (mode != Mode.TERMINATOR);
            }
            catch (ArgumentException)
            {
                // from readBits() calls
                return(null);
            }

#if WindowsCE
            var resultString = result.ToString().Replace("\n", "\r\n");
#else
            var resultString = result.ToString().Replace("\r\n", "\n").Replace("\n", Environment.NewLine);
#endif
            return(new DecoderResult(bytes,
                                     resultString,
                                     byteSegments.Count == 0 ? null : byteSegments,
                                     ecLevel == null ? null : ecLevel.ToString()));
        }
Beispiel #4
0
        /// <summary>
        /// Encodes the specified content.
        /// </summary>
        /// <param name="content">The content.</param>
        /// <param name="ecLevel">The ec level.</param>
        /// <param name="hints">The hints.</param>
        /// <returns></returns>
        public static QRCode encode(String content,
                                    ErrorCorrectionLevel ecLevel,
                                    IDictionary <EncodeHintType, object> hints)
        {
            // Determine what character encoding has been specified by the caller, if any
#if !SILVERLIGHT || WINDOWS_PHONE
            String encoding = hints == null || !hints.ContainsKey(EncodeHintType.CHARACTER_SET) ? null : (String)hints[EncodeHintType.CHARACTER_SET];
            if (encoding == null)
            {
                encoding = DEFAULT_BYTE_MODE_ENCODING;
            }
            bool generateECI = !DEFAULT_BYTE_MODE_ENCODING.Equals(encoding);
#else
            // Silverlight supports only UTF-8 and UTF-16 out-of-the-box
            const string encoding = "UTF-8";
            // caller of the method can only control if the ECI segment should be written
            // character set is fixed to UTF-8; but some scanners doesn't like the ECI segment
            bool generateECI = (hints != null && hints.ContainsKey(EncodeHintType.CHARACTER_SET));
#endif

            // Pick an encoding mode appropriate for the content. Note that this will not attempt to use
            // multiple modes / segments even if that were more efficient. Twould be nice.
            Mode mode = chooseMode(content, encoding);

            // This will store the header information, like mode and
            // length, as well as "header" segments like an ECI segment.
            BitArray headerBits = new BitArray();

            // Append ECI segment if applicable
            if (mode == Mode.BYTE && generateECI)
            {
                CharacterSetECI eci = CharacterSetECI.getCharacterSetECIByName(encoding);
                if (eci != null)
                {
                    var eciIsExplicitDisabled = (hints != null && hints.ContainsKey(EncodeHintType.DISABLE_ECI) ? (bool)hints[EncodeHintType.DISABLE_ECI] : false);
                    if (!eciIsExplicitDisabled)
                    {
                        appendECI(eci, headerBits);
                    }
                }
            }

            // (With ECI in place,) Write the mode marker
            appendModeInfo(mode, headerBits);

            // Collect data within the main segment, separately, to count its size if needed. Don't add it to
            // main payload yet.
            BitArray dataBits = new BitArray();
            appendBytes(content, mode, dataBits, encoding);

            // Hard part: need to know version to know how many bits length takes. But need to know how many
            // bits it takes to know version. First we take a guess at version by assuming version will be
            // the minimum, 1:

            int provisionalBitsNeeded = headerBits.Size
                                        + mode.getCharacterCountBits(Version.getVersionForNumber(1))
                                        + dataBits.Size;
            Version provisionalVersion = chooseVersion(provisionalBitsNeeded, ecLevel);

            // Use that guess to calculate the right version. I am still not sure this works in 100% of cases.
            int bitsNeeded = headerBits.Size
                             + mode.getCharacterCountBits(provisionalVersion)
                             + dataBits.Size;
            Version version = chooseVersion(bitsNeeded, ecLevel);

            BitArray headerAndDataBits = new BitArray();
            headerAndDataBits.appendBitArray(headerBits);
            // Find "length" of main segment and write it
            int numLetters = mode == Mode.BYTE ? dataBits.SizeInBytes : content.Length;
            appendLengthInfo(numLetters, version, mode, headerAndDataBits);
            // Put data together into the overall payload
            headerAndDataBits.appendBitArray(dataBits);

            Version.ECBlocks ecBlocks = version.getECBlocksForLevel(ecLevel);
            int numDataBytes          = version.TotalCodewords - ecBlocks.TotalECCodewords;

            // Terminate the bits properly.
            terminateBits(numDataBytes, headerAndDataBits);

            // Interleave data bits with error correction code.
            BitArray finalBits = interleaveWithECBytes(headerAndDataBits,
                                                       version.TotalCodewords,
                                                       numDataBytes,
                                                       ecBlocks.NumBlocks);

            QRCode qrCode = new QRCode
            {
                ECLevel = ecLevel,
                Mode    = mode,
                Version = version
            };

            //  Choose the mask pattern and set to "qrCode".
            int        dimension   = version.DimensionForVersion;
            ByteMatrix matrix      = new ByteMatrix(dimension, dimension);
            int        maskPattern = chooseMaskPattern(finalBits, ecLevel, version, matrix);
            qrCode.MaskPattern = maskPattern;

            // Build the matrix and set it to "qrCode".
            MatrixUtil.buildMatrix(finalBits, ecLevel, version, maskPattern, matrix);
            qrCode.Matrix = matrix;

            return(qrCode);
        }
Beispiel #5
0
 /// <summary>
 /// Encode "bytes" with the error correction level "ecLevel". The encoding mode will be chosen
 /// internally by chooseMode(). On success, store the result in "qrCode".
 /// We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
 /// "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
 /// strong error correction for this purpose.
 /// Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
 /// with which clients can specify the encoding mode. For now, we don't need the functionality.
 /// </summary>
 /// <param name="content">The content.</param>
 /// <param name="ecLevel">The ec level.</param>
 public static QRCode encode(String content, ErrorCorrectionLevel ecLevel)
 {
     return(encode(content, ecLevel, null));
 }
Beispiel #6
0
 /// <summary>
 /// Gets the EC blocks for level.
 /// </summary>
 /// <param name="ecLevel">The ec level.</param>
 /// <returns></returns>
 public ECBlocks getECBlocksForLevel(ErrorCorrectionLevel ecLevel)
 {
     return(ecBlocks[ecLevel.ordinal()]);
 }