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- /*
- * Copyright 2007 ZXing authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
- using System;
- using System.Collections.Generic;
- using System.Text;
-
- using ZXing.Common;
-
- namespace ZXing.QrCode.Internal
- {
- /// <summary> <p>QR Codes can encode text as bits in one of several modes, and can use multiple modes
- /// in one QR Code. This class decodes the bits back into text.</p>
- ///
- /// <p>See ISO 18004:2006, 6.4.3 - 6.4.7</p>
- /// <author>Sean Owen</author>
- /// </summary>
- internal static class DecodedBitStreamParser
- {
- /// <summary>
- /// See ISO 18004:2006, 6.4.4 Table 5
- /// </summary>
- private static readonly char[] ALPHANUMERIC_CHARS = {
- '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B',
- 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
- 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
- ' ', '$', '%', '*', '+', '-', '.', '/', ':'
- };
- private const int GB2312_SUBSET = 1;
-
- 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);
- var symbolSequence = -1;
- var parityData = -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; but sequence number and parity is added later to the result metadata
- // Read next 8 bits (symbol sequence #) and 8 bits (parity data), then continue
- symbolSequence = bits.readBits(8);
- parityData = bits.readBits(8);
- }
- 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, 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(),
- symbolSequence, parityData);
- }
-
- /// <summary>
- /// See specification GBT 18284-2000
- /// </summary>
- /// <param name="bits">The bits.</param>
- /// <param name="result">The result.</param>
- /// <param name="count">The count.</param>
- /// <returns></returns>
- private static bool decodeHanziSegment(BitSource bits,
- StringBuilder result,
- int count)
- {
- // Don't crash trying to read more bits than we have available.
- if (count * 13 > bits.available())
- {
- return false;
- }
-
- // Each character will require 2 bytes. Read the characters as 2-byte pairs
- // and decode as GB2312 afterwards
- byte[] buffer = new byte[2 * count];
- int offset = 0;
- while (count > 0)
- {
- // Each 13 bits encodes a 2-byte character
- int twoBytes = bits.readBits(13);
- int assembledTwoBytes = ((twoBytes / 0x060) << 8) | (twoBytes % 0x060);
- if (assembledTwoBytes < 0x003BF)
- {
- // In the 0xA1A1 to 0xAAFE range
- assembledTwoBytes += 0x0A1A1;
- }
- else
- {
- // In the 0xB0A1 to 0xFAFE range
- assembledTwoBytes += 0x0A6A1;
- }
- buffer[offset] = (byte)((assembledTwoBytes >> 8) & 0xFF);
- buffer[offset + 1] = (byte)(assembledTwoBytes & 0xFF);
- offset += 2;
- count--;
- }
-
- try
- {
- result.Append(Encoding.GetEncoding(StringUtils.GB2312).GetString(buffer, 0, buffer.Length));
- }
- #if (WINDOWS_PHONE70 || WINDOWS_PHONE71 || SILVERLIGHT4 || SILVERLIGHT5 || NETFX_CORE || MONOANDROID || MONOTOUCH)
- catch (ArgumentException)
- {
- try
- {
- // Silverlight only supports a limited number of character sets, trying fallback to UTF-8
- result.Append(Encoding.GetEncoding("UTF-8").GetString(buffer, 0, buffer.Length));
- }
- catch (Exception)
- {
- return false;
- }
- }
- #endif
- catch (Exception)
- {
- return false;
- }
-
- return true;
- }
-
- private static bool decodeKanjiSegment(BitSource bits,
- StringBuilder result,
- int count)
- {
- // Don't crash trying to read more bits than we have available.
- if (count * 13 > bits.available())
- {
- return false;
- }
-
- // Each character will require 2 bytes. Read the characters as 2-byte pairs
- // and decode as Shift_JIS afterwards
- byte[] buffer = new byte[2 * count];
- int offset = 0;
- while (count > 0)
- {
- // Each 13 bits encodes a 2-byte character
- int twoBytes = bits.readBits(13);
- int assembledTwoBytes = ((twoBytes / 0x0C0) << 8) | (twoBytes % 0x0C0);
- if (assembledTwoBytes < 0x01F00)
- {
- // In the 0x8140 to 0x9FFC range
- assembledTwoBytes += 0x08140;
- }
- else
- {
- // In the 0xE040 to 0xEBBF range
- assembledTwoBytes += 0x0C140;
- }
- buffer[offset] = (byte)(assembledTwoBytes >> 8);
- buffer[offset + 1] = (byte)assembledTwoBytes;
- offset += 2;
- count--;
- }
- // Shift_JIS may not be supported in some environments:
- try
- {
- result.Append(Encoding.GetEncoding(StringUtils.SHIFT_JIS).GetString(buffer, 0, buffer.Length));
- }
- #if (WINDOWS_PHONE70 || WINDOWS_PHONE71 || SILVERLIGHT4 || SILVERLIGHT5 || NETFX_CORE || MONOANDROID || MONOTOUCH)
- catch (ArgumentException)
- {
- try
- {
- // Silverlight only supports a limited number of character sets, trying fallback to UTF-8
- result.Append(Encoding.GetEncoding("UTF-8").GetString(buffer, 0, buffer.Length));
- }
- catch (Exception)
- {
- return false;
- }
- }
- #endif
- catch (Exception)
- {
- return false;
- }
- return true;
- }
-
- private static bool decodeByteSegment(BitSource bits,
- StringBuilder result,
- int count,
- IList<byte[]> byteSegments,
- IDictionary<DecodeHintType, object> hints)
- {
- // Don't crash trying to read more bits than we have available.
- if (count << 3 > bits.available())
- {
- return false;
- }
-
- byte[] readBytes = new byte[count];
- for (int i = 0; i < count; i++)
- {
- readBytes[i] = (byte)bits.readBits(8);
- }
- String encoding;
- encoding = StringUtils.guessEncoding(readBytes, hints);
-
- try
- {
- result.Append(Encoding.GetEncoding(encoding).GetString(readBytes, 0, readBytes.Length));
- }
- #if (WINDOWS_PHONE70 || WINDOWS_PHONE71 || SILVERLIGHT4 || SILVERLIGHT5 || NETFX_CORE || MONOANDROID || MONOTOUCH)
- catch (ArgumentException)
- {
- try
- {
- // Silverlight only supports a limited number of character sets, trying fallback to UTF-8
- result.Append(Encoding.GetEncoding("UTF-8").GetString(readBytes, 0, readBytes.Length));
- }
- catch (Exception)
- {
- return false;
- }
- }
- #endif
- #if WindowsCE
- catch (PlatformNotSupportedException)
- {
- try
- {
- // WindowsCE doesn't support all encodings. But it is device depended.
- // So we try here the some different ones
- if (encoding == "ISO-8859-1")
- {
- result.Append(Encoding.GetEncoding(1252).GetString(readBytes, 0, readBytes.Length));
- }
- else
- {
- result.Append(Encoding.GetEncoding("UTF-8").GetString(readBytes, 0, readBytes.Length));
- }
- }
- catch (Exception)
- {
- return false;
- }
- }
- #endif
- catch (Exception)
- {
- return false;
- }
- byteSegments.Add(readBytes);
-
- return true;
- }
-
- private static char toAlphaNumericChar(int value)
- {
- if (value >= ALPHANUMERIC_CHARS.Length)
- {
- //throw FormatException.Instance;
- }
- return ALPHANUMERIC_CHARS[value];
- }
-
- private static bool decodeAlphanumericSegment(BitSource bits,
- StringBuilder result,
- int count,
- bool fc1InEffect)
- {
- // Read two characters at a time
- int start = result.Length;
- while (count > 1)
- {
- if (bits.available() < 11)
- {
- return false;
- }
- int nextTwoCharsBits = bits.readBits(11);
- result.Append(toAlphaNumericChar(nextTwoCharsBits / 45));
- result.Append(toAlphaNumericChar(nextTwoCharsBits % 45));
- count -= 2;
- }
- if (count == 1)
- {
- // special case: one character left
- if (bits.available() < 6)
- {
- return false;
- }
- result.Append(toAlphaNumericChar(bits.readBits(6)));
- }
-
- // See section 6.4.8.1, 6.4.8.2
- if (fc1InEffect)
- {
- // We need to massage the result a bit if in an FNC1 mode:
- for (int i = start; i < result.Length; i++)
- {
- if (result[i] == '%')
- {
- if (i < result.Length - 1 && result[i + 1] == '%')
- {
- // %% is rendered as %
- result.Remove(i + 1, 1);
- }
- else
- {
- // In alpha mode, % should be converted to FNC1 separator 0x1D
- result.Remove(i, 1);
- result.Insert(i, new[] { (char)0x1D });
- }
- }
- }
- }
-
- return true;
- }
-
- private static bool decodeNumericSegment(BitSource bits,
- StringBuilder result,
- int count)
- {
- // Read three digits at a time
- while (count >= 3)
- {
- // Each 10 bits encodes three digits
- if (bits.available() < 10)
- {
- return false;
- }
- int threeDigitsBits = bits.readBits(10);
- if (threeDigitsBits >= 1000)
- {
- return false;
- }
- result.Append(toAlphaNumericChar(threeDigitsBits / 100));
- result.Append(toAlphaNumericChar((threeDigitsBits / 10) % 10));
- result.Append(toAlphaNumericChar(threeDigitsBits % 10));
-
- count -= 3;
- }
- if (count == 2)
- {
- // Two digits left over to read, encoded in 7 bits
- if (bits.available() < 7)
- {
- return false;
- }
- int twoDigitsBits = bits.readBits(7);
- if (twoDigitsBits >= 100)
- {
- return false;
- }
- result.Append(toAlphaNumericChar(twoDigitsBits / 10));
- result.Append(toAlphaNumericChar(twoDigitsBits % 10));
- }
- else if (count == 1)
- {
- // One digit left over to read
- if (bits.available() < 4)
- {
- return false;
- }
- int digitBits = bits.readBits(4);
- if (digitBits >= 10)
- {
- return false;
- }
- result.Append(toAlphaNumericChar(digitBits));
- }
-
- return true;
- }
-
- private static int parseECIValue(BitSource bits)
- {
- int firstByte = bits.readBits(8);
- if ((firstByte & 0x80) == 0)
- {
- // just one byte
- return firstByte & 0x7F;
- }
- if ((firstByte & 0xC0) == 0x80)
- {
- // two bytes
- int secondByte = bits.readBits(8);
- return ((firstByte & 0x3F) << 8) | secondByte;
- }
- if ((firstByte & 0xE0) == 0xC0)
- {
- // three bytes
- int secondThirdBytes = bits.readBits(16);
- return ((firstByte & 0x1F) << 16) | secondThirdBytes;
- }
- throw new ArgumentException("Bad ECI bits starting with byte " + firstByte);
- }
- }
- }
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