/*
* 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 ReaderException = com.google.zxing.ReaderException;
using BitSource = com.google.zxing.common.BitSource;
using CharacterSetECI = com.google.zxing.common.CharacterSetECI;
using DecoderResult = com.google.zxing.common.DecoderResult;
namespace com.google.zxing.qrcode.decoder
{
/// <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>
///
/// </summary>
/// <author> Sean Owen
/// </author>
/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source
/// </author>
sealed class DecodedBitStreamParser
{
/// <summary> See ISO 18004:2006, 6.4.4 Table 5</summary>
//UPGRADE_NOTE: Final was removed from the declaration of 'ALPHANUMERIC_CHARS'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
private static readonly char[] ALPHANUMERIC_CHARS = new char[]{'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 System.String SHIFT_JIS = "SJIS";
private const System.String EUC_JP = "EUC_JP";
private static bool ASSUME_SHIFT_JIS;
private const System.String UTF8 = "UTF8";
// Redivivus.in Java to c# Porting update
// 30/01/2010
// Commented & Added
private const System.String ISO88591 = "ISO-8859-1";
private DecodedBitStreamParser()
{
}
internal static DecoderResult decode(sbyte[] bytes, Version version, ErrorCorrectionLevel ecLevel)
{
BitSource bits = new BitSource(bytes);
System.Text.StringBuilder result = new System.Text.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 (System.ArgumentException iae)
{
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);
}
private static void decodeKanjiSegment(BitSource bits, System.Text.StringBuilder result, int count)
{
// Each character will require 2 bytes. Read the characters as 2-byte pairs
// and decode as Shift_JIS afterwards
sbyte[] buffer = new sbyte[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] = (sbyte) (assembledTwoBytes >> 8);
buffer[offset + 1] = (sbyte) assembledTwoBytes;
offset += 2;
count--;
}
// Shift_JIS may not be supported in some environments:
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(System.Text.Encoding.GetEncoding(SHIFT_JIS).GetString(SupportClass.ToByteArray(buffer)));
}
catch (System.IO.IOException uee)
{
throw ReaderException.Instance;
}
}
private static void decodeByteSegment(BitSource bits, System.Text.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);
}
System.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 = guessEncoding(readBytes);
}
else
{
encoding = 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(System.Text.Encoding.GetEncoding(encoding).GetString(SupportClass.ToByteArray(readBytes)));
}
catch (System.IO.IOException uce)
{
throw ReaderException.Instance;
}
byteSegments.Add(SupportClass.ToByteArray(readBytes));
}
private static void decodeAlphanumericSegment(BitSource bits, System.Text.StringBuilder result, int count, bool fc1InEffect)
{
// Read two characters at a time
int start = result.Length;
while (count > 1)
{
int nextTwoCharsBits = bits.readBits(11);
result.Append(ALPHANUMERIC_CHARS[nextTwoCharsBits / 45]);
result.Append(ALPHANUMERIC_CHARS[nextTwoCharsBits % 45]);
count -= 2;
}
if (count == 1)
{
// special case: one character left
result.Append(ALPHANUMERIC_CHARS[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[i] = (char) 0x1D;
}
}
}
}
}
private static void decodeNumericSegment(BitSource bits, System.Text.StringBuilder result, int count)
{
// Read three digits at a time
while (count >= 3)
{
// Each 10 bits encodes three digits
int threeDigitsBits = bits.readBits(10);
if (threeDigitsBits >= 1000)
{
throw ReaderException.Instance;
}
result.Append(ALPHANUMERIC_CHARS[threeDigitsBits / 100]);
result.Append(ALPHANUMERIC_CHARS[(threeDigitsBits / 10) % 10]);
result.Append(ALPHANUMERIC_CHARS[threeDigitsBits % 10]);
count -= 3;
}
if (count == 2)
{
// Two digits left over to read, encoded in 7 bits
int twoDigitsBits = bits.readBits(7);
if (twoDigitsBits >= 100)
{
throw ReaderException.Instance;
}
result.Append(ALPHANUMERIC_CHARS[twoDigitsBits / 10]);
result.Append(ALPHANUMERIC_CHARS[twoDigitsBits % 10]);
}
else if (count == 1)
{
// One digit left over to read
int digitBits = bits.readBits(4);
if (digitBits >= 10)
{
throw ReaderException.Instance;
}
result.Append(ALPHANUMERIC_CHARS[digitBits]);
}
}
private static System.String guessEncoding(sbyte[] bytes)
{
if (ASSUME_SHIFT_JIS)
{
return SHIFT_JIS;
}
// Does it start with the UTF-8 byte order mark? then guess it's UTF-8
if (bytes.Length > 3 && bytes[0] == (sbyte) SupportClass.Identity(0xEF) && bytes[1] == (sbyte) SupportClass.Identity(0xBB) && bytes[2] == (sbyte) SupportClass.Identity(0xBF))
{
return UTF8;
}
// For now, merely tries to distinguish ISO-8859-1, UTF-8 and Shift_JIS,
// which should be by far the most common encodings. ISO-8859-1
// should not have bytes in the 0x80 - 0x9F range, while Shift_JIS
// uses this as a first byte of a two-byte character. If we see this
// followed by a valid second byte in Shift_JIS, assume it is Shift_JIS.
// If we see something else in that second byte, we'll make the risky guess
// that it's UTF-8.
int length = bytes.Length;
bool canBeISO88591 = true;
bool canBeShiftJIS = true;
int maybeDoubleByteCount = 0;
int maybeSingleByteKatakanaCount = 0;
bool sawLatin1Supplement = false;
bool lastWasPossibleDoubleByteStart = false;
for (int i = 0; i < length && (canBeISO88591 || canBeShiftJIS); i++)
{
int value_Renamed = bytes[i] & 0xFF;
if ((value_Renamed == 0xC2 || value_Renamed == 0xC3) && i < length - 1)
{
// This is really a poor hack. The slightly more exotic characters people might want to put in
// a QR Code, by which I mean the Latin-1 supplement characters (e.g. u-umlaut) have encodings
// that start with 0xC2 followed by [0xA0,0xBF], or start with 0xC3 followed by [0x80,0xBF].
int nextValue = bytes[i + 1] & 0xFF;
if (nextValue <= 0xBF && ((value_Renamed == 0xC2 && nextValue >= 0xA0) || (value_Renamed == 0xC3 && nextValue >= 0x80)))
{
sawLatin1Supplement = true;
}
}
if (value_Renamed >= 0x7F && value_Renamed <= 0x9F)
{
canBeISO88591 = false;
}
if (value_Renamed >= 0xA1 && value_Renamed <= 0xDF)
{
// count the number of characters that might be a Shift_JIS single-byte Katakana character
if (!lastWasPossibleDoubleByteStart)
{
maybeSingleByteKatakanaCount++;
}
}
if (!lastWasPossibleDoubleByteStart && ((value_Renamed >= 0xF0 && value_Renamed <= 0xFF) || value_Renamed == 0x80 || value_Renamed == 0xA0))
{
canBeShiftJIS = false;
}
if (((value_Renamed >= 0x81 && value_Renamed <= 0x9F) || (value_Renamed >= 0xE0 && value_Renamed <= 0xEF)))
{
// These start double-byte characters in Shift_JIS. Let's see if it's followed by a valid
// second byte.
if (lastWasPossibleDoubleByteStart)
{
// If we just checked this and the last byte for being a valid double-byte
// char, don't check starting on this byte. If this and the last byte
// formed a valid pair, then this shouldn't be checked to see if it starts
// a double byte pair of course.
lastWasPossibleDoubleByteStart = false;
}
else
{
// ... otherwise do check to see if this plus the next byte form a valid
// double byte pair encoding a character.
lastWasPossibleDoubleByteStart = true;
if (i >= bytes.Length - 1)
{
canBeShiftJIS = false;
}
else
{
int nextValue = bytes[i + 1] & 0xFF;
if (nextValue < 0x40 || nextValue > 0xFC)
{
canBeShiftJIS = false;
}
else
{
maybeDoubleByteCount++;
}
// There is some conflicting information out there about which bytes can follow which in
// double-byte Shift_JIS characters. The rule above seems to be the one that matches practice.
}
}
}
else
{
lastWasPossibleDoubleByteStart = false;
}
}
// Distinguishing Shift_JIS and ISO-8859-1 can be a little tough. The crude heuristic is:
// - If we saw
// - at least three byte that starts a double-byte value (bytes that are rare in ISO-8859-1), or
// - over 5% of bytes that could be single-byte Katakana (also rare in ISO-8859-1),
// - and, saw no sequences that are invalid in Shift_JIS, then we conclude Shift_JIS
if (canBeShiftJIS && (maybeDoubleByteCount >= 3 || 20 * maybeSingleByteKatakanaCount > length))
{
return SHIFT_JIS;
}
// Otherwise, we default to ISO-8859-1 unless we know it can't be
if (!sawLatin1Supplement && canBeISO88591)
{
return ISO88591;
}
// Otherwise, we take a wild guess with UTF-8
return UTF8;
}
private static int parseECIValue(BitSource bits)
{
int firstByte = bits.readBits(8);
if ((firstByte & 0x80) == 0)
{
// just one byte
return firstByte & 0x7F;
}
else if ((firstByte & 0xC0) == 0x80)
{
// two bytes
int secondByte = bits.readBits(8);
return ((firstByte & 0x3F) << 8) | secondByte;
}
else if ((firstByte & 0xE0) == 0xC0)
{
// three bytes
int secondThirdBytes = bits.readBits(16);
return ((firstByte & 0x1F) << 16) | secondThirdBytes;
}
throw new System.ArgumentException("Bad ECI bits starting with byte " + firstByte);
}
static DecodedBitStreamParser()
{
{
// Redivivus.in Java to c# Porting update
// 30/01/2010
// Commented & Added
//System.String platformDefault = System_Renamed.getProperty("file.encoding");
//ASSUME_SHIFT_JIS = SHIFT_JIS.ToUpper().Equals(platformDefault.ToUpper()) || EUC_JP.ToUpper().Equals(platformDefault.ToUpper());
ASSUME_SHIFT_JIS = false;
}
}
}
}