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 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 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 void DecodeByteSegment(BitSource bits, StringBuilder result, int count, CharacterSetECI currentCharacterSetECI, System.Collections.ArrayList byteSegments)
{
sbyte[] readBytes = new sbyte[count];
if (count << 3 > bits.Available())
{
throw ReaderException.Instance;
}
for (int i = 0; i < count; i++)
{
readBytes[i] = (sbyte)bits.ReadBits(8);
}
// The spec isn't clear on this mode; see
// section 6.4.5: t does not say which encoding to assuming
// upon decoding. I have seen ISO-8859-1 used as well as
// Shift_JIS -- without anything like an ECI designator to
// give a hint.
var encoding = currentCharacterSetECI == null?GuessEncoding(readBytes) : currentCharacterSetECI.EncodingName;
try
{
//UPGRADE_TODO: The differences in the Format of parameters for constructor 'java.lang.String.String' may cause compilation errors. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1092'"
result.Append(Encoding.GetEncoding(encoding).GetString(SupportClass.ToByteArray(readBytes)));
}
catch (IOException)
{
throw ReaderException.Instance;
}
byteSegments.Add(SupportClass.ToByteArray(readBytes));
}
/// <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));
}
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);
}
}
catch (Exception)
{
return(false);
}
return(true);
}
private static bool DecodeByteSegment(BitSource bits,
StringBuilder result,
int count,
CharacterSetECI currentCharacterSetECI,
IList <byte[]> byteSegments)
{
// 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;
if (currentCharacterSetECI == null)
{
// The spec isn't clear on this mode; see
// section 6.4.5: t does not say which encoding to assuming
// upon decoding. I have seen ISO-8859-1 used as well as
// Shift_JIS -- without anything like an ECI designator to
// give a hint.
encoding = StringUtils.GuessEncoding(readBytes);
}
else
{
encoding = currentCharacterSetECI.EncodingName;
}
try
{
result.Append(Encoding.GetEncoding(encoding).GetString(readBytes, 0, readBytes.Length));
}
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);
}
}
catch (Exception)
{
return(false);
}
byteSegments.Add(readBytes);
return(true);
}
internal static DecoderResult Decode(byte[] bytes,
Version version,
ErrorCorrectionLevel ecLevel)
{
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);
}
}
switch (mode.Name)
{
case Mode.Names.TERMINATOR:
break;
case Mode.Names.FNC1_FIRST_POSITION:
case Mode.Names.FNC1_SECOND_POSITION:
// We do little with FNC1 except alter the parsed result a bit according to the spec
fc1InEffect = true;
break;
case Mode.Names.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);
break;
case Mode.Names.ECI:
// Count doesn't apply to ECI
int value = ParseECIValue(bits);
currentCharacterSetECI = CharacterSetECI.GetCharacterSetECIByValue(value);
if (currentCharacterSetECI == null)
{
return(null);
}
break;
case Mode.Names.HANZI:
// First handle Hanzi mode which does not start with character count
//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);
}
}
break;
default:
// "Normal" QR code modes:
// How many characters will follow, encoded in this mode?
int count = bits.ReadBits(mode.GetCharacterCountBits(version));
switch (mode.Name)
{
case Mode.Names.NUMERIC:
if (!DecodeNumericSegment(bits, result, count))
{
return(null);
}
break;
case Mode.Names.ALPHANUMERIC:
if (!DecodeAlphanumericSegment(bits, result, count, fc1InEffect))
{
return(null);
}
break;
case Mode.Names.BYTE:
if (!DecodeByteSegment(bits, result, count, currentCharacterSetECI, byteSegments))
{
return(null);
}
break;
case Mode.Names.KANJI:
if (!DecodeKanjiSegment(bits, result, count))
{
return(null);
}
break;
default:
return(null);
}
break;
}
} while (mode != Mode.TERMINATOR);
}
catch (ArgumentException)
{
// from readBits() calls
return(null);
}
var resultString = result.ToString().Replace("\r\n", "\n").Replace("\n", Environment.NewLine);
return(new DecoderResult(bytes, resultString));
}
internal static DecoderResult Decode(sbyte[] bytes, Version version, ErrorCorrectionLevel ecLevel)
{
BitSource bits = new BitSource(bytes);
StringBuilder result = new StringBuilder(50);
CharacterSetECI currentCharacterSetECI = null;
bool fc1InEffect = false;
System.Collections.ArrayList byteSegments = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(1));
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)
{
throw ReaderException.Instance;
}
}
if (!mode.Equals(Mode.TERMINATOR))
{
if (mode.Equals(Mode.FNC1_FIRST_POSITION) || mode.Equals(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.Equals(Mode.STRUCTURED_APPEND))
{
// 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.Equals(Mode.ECI))
{
// Count doesn't apply to ECI
int value_Renamed = ParseECIValue(bits);
currentCharacterSetECI = CharacterSetECI.GetCharacterSetECIByValue(value_Renamed);
if (currentCharacterSetECI == null)
{
throw ReaderException.Instance;
}
}
else
{
// How many characters will follow, encoded in this mode?
int count = bits.ReadBits(mode.GetCharacterCountBits(version));
if (mode.Equals(Mode.NUMERIC))
{
DecodeNumericSegment(bits, result, count);
}
else if (mode.Equals(Mode.ALPHANUMERIC))
{
DecodeAlphanumericSegment(bits, result, count, fc1InEffect);
}
else if (mode.Equals(Mode.BYTE))
{
DecodeByteSegment(bits, result, count, currentCharacterSetECI, byteSegments);
}
else if (mode.Equals(Mode.KANJI))
{
DecodeKanjiSegment(bits, result, count);
}
else
{
throw ReaderException.Instance;
}
}
}
}while (!mode.Equals(Mode.TERMINATOR));
return(new DecoderResult(bytes, result.ToString(), (byteSegments.Count == 0)?null:byteSegments, ecLevel));
}