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Diffstat (limited to 'libraries/zxing/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java')
| -rw-r--r-- | libraries/zxing/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java | 322 |
1 files changed, 0 insertions, 322 deletions
diff --git a/libraries/zxing/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java b/libraries/zxing/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java deleted file mode 100644 index ff374ac50..000000000 --- a/libraries/zxing/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java +++ /dev/null @@ -1,322 +0,0 @@ -/* - * 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. - */ - -package com.google.zxing.qrcode.decoder; - -import com.google.zxing.FormatException; -import com.google.zxing.common.BitSource; -import com.google.zxing.common.CharacterSetECI; -import com.google.zxing.common.DecoderResult; -import com.google.zxing.common.StringUtils; - -import java.io.UnsupportedEncodingException; -import java.util.Hashtable; -import java.util.Vector; - -/** - * <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 - */ -final class DecodedBitStreamParser { - - /** - * See ISO 18004:2006, 6.4.4 Table 5 - */ - private static final 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 static final int GB2312_SUBSET = 1; - - private DecodedBitStreamParser() { - } - - static DecoderResult decode(byte[] bytes, Version version, ErrorCorrectionLevel ecLevel, Hashtable hints) - throws FormatException { - BitSource bits = new BitSource(bytes); - StringBuffer result = new StringBuffer(50); - CharacterSetECI currentCharacterSetECI = null; - boolean fc1InEffect = false; - Vector byteSegments = new Vector(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 (IllegalArgumentException iae) { - throw FormatException.getFormatInstance(); - } - } - 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 = parseECIValue(bits); - currentCharacterSetECI = CharacterSetECI.getCharacterSetECIByValue(value); - if (currentCharacterSetECI == null) { - throw FormatException.getFormatInstance(); - } - } else { - // First handle Hanzi mode which does not start with character count - if (mode.equals(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) { - decodeHanziSegment(bits, result, countHanzi); - } - } else { - // "Normal" QR code modes: - // 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, hints); - } else if (mode.equals(Mode.KANJI)) { - decodeKanjiSegment(bits, result, count); - } else { - throw FormatException.getFormatInstance(); - } - } - } - } - } while (!mode.equals(Mode.TERMINATOR)); - - return new DecoderResult(bytes, - result.toString(), - byteSegments.isEmpty() ? null : byteSegments, - ecLevel == null ? null : ecLevel.toString()); - } - - /** - * See specification GBT 18284-2000 - */ - private static void decodeHanziSegment(BitSource bits, - StringBuffer result, - int count) throws FormatException { - // Don't crash trying to read more bits than we have available. - if (count * 13 > bits.available()) { - throw FormatException.getFormatInstance(); - } - - // 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(new String(buffer, StringUtils.GB2312)); - } catch (UnsupportedEncodingException uee) { - throw FormatException.getFormatInstance(); - } - } - - private static void decodeKanjiSegment(BitSource bits, - StringBuffer result, - int count) throws FormatException { - // Don't crash trying to read more bits than we have available. - if (count * 13 > bits.available()) { - throw FormatException.getFormatInstance(); - } - - // 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(new String(buffer, StringUtils.SHIFT_JIS)); - } catch (UnsupportedEncodingException uee) { - throw FormatException.getFormatInstance(); - } - } - - private static void decodeByteSegment(BitSource bits, - StringBuffer result, - int count, - CharacterSetECI currentCharacterSetECI, - Vector byteSegments, - Hashtable hints) throws FormatException { - // Don't crash trying to read more bits than we have available. - if (count << 3 > bits.available()) { - throw FormatException.getFormatInstance(); - } - - 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, hints); - } else { - encoding = currentCharacterSetECI.getEncodingName(); - } - try { - result.append(new String(readBytes, encoding)); - } catch (UnsupportedEncodingException uce) { - throw FormatException.getFormatInstance(); - } - byteSegments.addElement(readBytes); - } - - private static char toAlphaNumericChar(int value) throws FormatException { - if (value >= ALPHANUMERIC_CHARS.length) { - throw FormatException.getFormatInstance(); - } - return ALPHANUMERIC_CHARS[value]; - } - - private static void decodeAlphanumericSegment(BitSource bits, - StringBuffer result, - int count, - boolean fc1InEffect) throws FormatException { - // Read two characters at a time - int start = result.length(); - while (count > 1) { - 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 - 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.charAt(i) == '%') { - if (i < result.length() - 1 && result.charAt(i + 1) == '%') { - // %% is rendered as % - result.deleteCharAt(i + 1); - } else { - // In alpha mode, % should be converted to FNC1 separator 0x1D - result.setCharAt(i, (char) 0x1D); - } - } - } - } - } - - private static void decodeNumericSegment(BitSource bits, - StringBuffer result, - int count) throws FormatException { - // Read three digits at a time - while (count >= 3) { - // Each 10 bits encodes three digits - int threeDigitsBits = bits.readBits(10); - if (threeDigitsBits >= 1000) { - throw FormatException.getFormatInstance(); - } - 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 - int twoDigitsBits = bits.readBits(7); - if (twoDigitsBits >= 100) { - throw FormatException.getFormatInstance(); - } - result.append(toAlphaNumericChar(twoDigitsBits / 10)); - result.append(toAlphaNumericChar(twoDigitsBits % 10)); - } else if (count == 1) { - // One digit left over to read - int digitBits = bits.readBits(4); - if (digitBits >= 10) { - throw FormatException.getFormatInstance(); - } - result.append(toAlphaNumericChar(digitBits)); - } - } - - 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 IllegalArgumentException("Bad ECI bits starting with byte " + firstByte); - } - -} |