de.uniks.networkparser.bytes.qr.DecodedBitStreamParser Maven / Gradle / Ivy
/*
* Copyright 2008 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 de.uniks.networkparser.bytes.qr;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
/**
*
* 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.
*
*
*
* See ISO 18004:2006, 6.4.3 - 6.4.7
*
*
* @author Sean Owen
*/
final class DecodedBitStreamParser {
public static final String SHIFT_JIS = "SJIS";
public static final String GB2312 = "GB2312";
/**
* 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) throws Exception {
BitArray bits = new BitArray(bytes);
StringBuilder result = new StringBuilder(50);
List byteSegments = new ArrayList(1);
int symbolSequence = -1;
int parityData = -1;
try {
boolean 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 {
mode = Mode.forBits(bits.readBits(4)); // mode is encoded by
// 4 bits
}
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) {
throw new RuntimeException("FormatException");
}
// 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);
} 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) {
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 == Mode.NUMERIC) {
decodeNumericSegment(bits, result, count);
} else if (mode == Mode.ALPHANUMERIC) {
decodeAlphanumericSegment(bits, result, count, fc1InEffect);
} else if (mode == Mode.BYTE) {
decodeByteSegment(bits, result, count, byteSegments);
} else if (mode == Mode.KANJI) {
decodeKanjiSegment(bits, result, count);
} else {
throw new RuntimeException("FormatException");
}
}
}
}
} while (mode != Mode.TERMINATOR);
} catch (IllegalArgumentException iae) {
// from readBits() calls
throw new RuntimeException("FormatException");
}
return new DecoderResult(bytes, result.toString(), byteSegments.isEmpty() ? null : byteSegments,
ecLevel == null ? null : ecLevel.toString(), symbolSequence, parityData);
}
/**
* See specification GBT 18284-2000
* @param bits result bits
* @param result result String
* @param count count of value
*/
private static void decodeHanziSegment(BitArray bits, StringBuilder result, int count) throws Exception {
// Don't crash trying to read more bits than we have available.
if (count * 13 > bits.available()) {
throw new RuntimeException("FormatException");
}
// 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, GB2312));
} catch (UnsupportedEncodingException ignored) {
throw new RuntimeException("FormatException");
}
}
private static void decodeKanjiSegment(BitArray bits, StringBuilder result, int count) throws Exception {
// Don't crash trying to read more bits than we have available.
if (count * 13 > bits.available()) {
throw new RuntimeException("FormatException");
}
// 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, SHIFT_JIS));
} catch (UnsupportedEncodingException ignored) {
throw new RuntimeException("FormatException");
}
}
private static void decodeByteSegment(BitArray bits, StringBuilder result, int count,
Collection byteSegments) throws Exception {
// Don't crash trying to read more bits than we have available.
if (8 * count > bits.available()) {
throw new RuntimeException("FormatException");
}
byte[] readBytes = new byte[count];
for (int i = 0; i < count; i++) {
readBytes[i] = (byte) bits.readBits(8);
}
result.append(new String(readBytes, Charset.forName("UTF-8")));
byteSegments.add(readBytes);
}
private static char toAlphaNumericChar(int value) throws Exception {
if (value >= ALPHANUMERIC_CHARS.length) {
throw new RuntimeException("FormatException");
}
return ALPHANUMERIC_CHARS[value];
}
private static void decodeAlphanumericSegment(BitArray bits, StringBuilder result, int count, boolean fc1InEffect)
throws Exception {
// Read two characters at a time
int start = result.length();
while (count > 1) {
if (bits.available() < 11) {
throw new RuntimeException("FormatException");
}
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) {
throw new RuntimeException("FormatException");
}
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(BitArray bits, StringBuilder result, int count) throws Exception {
// Read three digits at a time
while (count >= 3) {
// Each 10 bits encodes three digits
if (bits.available() < 10) {
throw new RuntimeException("FormatException");
}
int threeDigitsBits = bits.readBits(10);
if (threeDigitsBits >= 1000) {
throw new RuntimeException("FormatException");
}
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) {
throw new RuntimeException("FormatException");
}
int twoDigitsBits = bits.readBits(7);
if (twoDigitsBits >= 100) {
throw new RuntimeException("FormatException");
}
result.append(toAlphaNumericChar(twoDigitsBits / 10));
result.append(toAlphaNumericChar(twoDigitsBits % 10));
} else if (count == 1) {
// One digit left over to read
if (bits.available() < 4) {
throw new RuntimeException("FormatException");
}
int digitBits = bits.readBits(4);
if (digitBits >= 10) {
throw new RuntimeException("FormatException");
}
result.append(toAlphaNumericChar(digitBits));
}
}
}
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