/*
* QR Code generator library (Java)
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
package io.nayuki.qrcodegen;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;
/**
* Represents a character string to be encoded in a QR Code symbol. Each segment has
* a mode, and a sequence of characters that is already encoded as a sequence of bits.
* Instances of this class are immutable.
* <p>This segment class imposes no length restrictions, but QR Codes have restrictions.
* Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
* Any segment longer than this is meaningless for the purpose of generating QR Codes.</p>
*/
public final class QrSegment {
/*---- Static factory functions ----*/
/**
* Returns a segment representing the specified binary data encoded in byte mode.
* @param data the binary data
* @return a segment containing the data
* @throws NullPointerException if the array is {@code null}
*/
public static QrSegment makeBytes(byte[] data) {
if (data == null)
throw new NullPointerException();
return new QrSegment(Mode.BYTE, data.length, data, data.length * 8);
}
/**
* Returns a segment representing the specified string of decimal digits encoded in numeric mode.
* @param digits a string consisting of digits from 0 to 9
* @return a segment containing the data
* @throws NullPointerException if the string is {@code null}
* @throws IllegalArgumentException if the string contains non-digit characters
*/
public static QrSegment makeNumeric(String digits) {
if (digits == null)
throw new NullPointerException();
if (!NUMERIC_REGEX.matcher(digits).matches())
throw new IllegalArgumentException("String contains non-numeric characters");
BitBuffer bb = new BitBuffer();
int i;
for (i = 0; i + 3 <= digits.length(); i += 3) // Process groups of 3
bb.appendBits(Integer.parseInt(digits.substring(i, i + 3)), 10);
int rem = digits.length() - i;
if (rem > 0) // 1 or 2 digits remaining
bb.appendBits(Integer.parseInt(digits.substring(i)), rem * 3 + 1);
return new QrSegment(Mode.NUMERIC, digits.length(), bb.getBytes(), bb.bitLength());
}
/**
* Returns a segment representing the specified text string encoded in alphanumeric mode. The characters allowed are:
* 0 to 9, A to Z (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
* @param text a string of text, with only certain characters allowed
* @return a segment containing the data
* @throws NullPointerException if the string is {@code null}
* @throws IllegalArgumentException if the string contains non-encodable characters
*/
public static QrSegment makeAlphanumeric(String text) {
if (text == null)
throw new NullPointerException();
if (!ALPHANUMERIC_REGEX.matcher(text).matches())
throw new IllegalArgumentException("String contains unencodable characters in alphanumeric mode");
BitBuffer bb = new BitBuffer();
int i;
for (i = 0; i + 2 <= text.length(); i += 2) { // Process groups of 2
int temp = ALPHANUMERIC_ENCODING_TABLE[text.charAt(i) - ' '] * 45;
temp += ALPHANUMERIC_ENCODING_TABLE[text.charAt(i + 1) - ' '];
bb.appendBits(temp, 11);
}
if (i < text.length()) // 1 character remaining
bb.appendBits(ALPHANUMERIC_ENCODING_TABLE[text.charAt(i) - ' '], 6);
return new QrSegment(Mode.ALPHANUMERIC, text.length(), bb.getBytes(), bb.bitLength());
}
/**
* Returns a new mutable list of zero or more segments to represent the specified Unicode text string.
* The result may use various segment modes and switch modes to optimize the length of the bit stream.
* @param text the text to be encoded, which can be any Unicode string
* @return a list of segments containing the text
* @throws NullPointerException if the text is {@code null}
*/
public static List<QrSegment> makeSegments(String text) {
if (text == null)
throw new NullPointerException();
// Select the most efficient segment encoding automatically
if (text.equals(""))
return new ArrayList<>();
QrSegment seg;
if (NUMERIC_REGEX.matcher(text).matches())
seg = makeNumeric(text);
else if (ALPHANUMERIC_REGEX.matcher(text).matches())
seg = makeAlphanumeric(text);
else
seg = makeBytes(text.getBytes(StandardCharsets.UTF_8));
return Arrays.asList(seg);
}
/*---- Instance fields ----*/
/** The mode indicator for this segment. Never {@code null}. */
public final Mode mode;
/** The length of this segment's unencoded data, measured in characters. Always zero or positive. */
public final int numChars;
/** The bits of this segment packed into a byte array in big endian. Accessed through {@link getByte(int)}. Not {@code null}. */
private final byte[] data;
/** The length of this segment's encoded data, measured in bits. Satisfies 0 ≤ {@code bitLength} ≤ {@code data.length} × 8. */
public final int bitLength;
/*---- Constructor ----*/
/**
* Creates a new QR Code data segment with the specified parameters and data.
* @param md the mode, which is not {@code null}
* @param numCh the data length in characters, which is non-negative
* @param bitLen the data length in bits, which is non-negative
* @param b the bits packed into bytes, which is not {@code null}
* @throws NullPointerException if the mode or array is {@code null}
* @throws IllegalArgumentException if the character count or bit length are negative or invalid
*/
public QrSegment(Mode md, int numCh, byte[] b, int bitLen) {
if (md == null || b == null)
throw new NullPointerException();
if (numCh < 0 || bitLen < 0 || bitLen > b.length * 8L)
throw new IllegalArgumentException("Invalid value");
mode = md;
numChars = numCh;
data = Arrays.copyOf(b, (bitLen + 7) / 8); // Trim to precise length and also make defensive copy
bitLength = bitLen;
}
/*---- Method ----*/
/**
* Returns the data byte at the specified index.
* @param index the index to retrieve from, satisfying 0 ≤ {@code index} < ceil({@code bitLength} ÷ 8)
* @return the data byte at the specified index
* @throws IndexOutOfBoundsException if the index is out of bounds
*/
public byte getByte(int index) {
if (index < 0 || index > data.length)
throw new IndexOutOfBoundsException();
return data[index];
}
// Package-private helper function.
static int getTotalBits(List<QrSegment> segs, int version) {
if (segs == null)
throw new NullPointerException();
if (version < 1 || version > 40)
throw new IllegalArgumentException("Version number out of range");
int result = 0;
for (QrSegment seg : segs) {
if (seg == null)
throw new NullPointerException();
int ccbits = seg.mode.numCharCountBits(version);
// Fail if segment length value doesn't fit in the length field's bit-width
if (seg.numChars >= (1 << ccbits))
return -1;
result += 4 + ccbits + seg.bitLength;
}
return result;
}
/*---- Constants ----*/
/** Can test whether a string is encodable in numeric mode (such as by using {@link #makeNumeric(String)}). */
public static final Pattern NUMERIC_REGEX = Pattern.compile("[0-9]*");
/** Can test whether a string is encodable in alphanumeric mode (such as by using {@link #makeAlphanumeric(String)}). */
public static final Pattern ALPHANUMERIC_REGEX = Pattern.compile("[A-Z0-9 $%*+./:-]*");
private static final byte[] ALPHANUMERIC_ENCODING_TABLE = {
// SP, !, ", #, $, %, &, ', (, ), *, +, ,, -, ., /, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, :, ;, <, =, >, ?, @, // ASCII codes 32 to 64
36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, -1, // Array indices 0 to 32
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, // Array indices 33 to 58
// 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, // ASCII codes 65 to 90
};
/*---- Public helper enumeration ----*/
/**
* The mode field of a segment. Immutable. Provides methods to retrieve closely related values.
*/
public enum Mode {
// Constants.
NUMERIC (0x1, 10, 12, 14),
ALPHANUMERIC(0x2, 9, 11, 13),
BYTE (0x4, 8, 16, 16),
KANJI (0x8, 8, 10, 12);
/*-- Fields --*/
/** An unsigned 4-bit integer value (range 0 to 15) representing the mode indicator bits for this mode object. */
public final int modeBits;
private final int[] numBitsCharCount;
// Constructor.
private Mode(int mode, int... ccbits) {
this.modeBits = mode;
numBitsCharCount = ccbits;
}
/*-- Method --*/
/**
* Returns the bit width of the segment character count field for this mode object at the specified version number.
* @param ver the version number, which is between 1 to 40, inclusive
* @return the number of bits for the character count, which is between 8 to 16, inclusive
* @throws IllegalArgumentException if the version number is out of range
*/
public int numCharCountBits(int ver) {
if ( 1 <= ver && ver <= 9) return numBitsCharCount[0];
else if (10 <= ver && ver <= 26) return numBitsCharCount[1];
else if (27 <= ver && ver <= 40) return numBitsCharCount[2];
else throw new IllegalArgumentException("Version number out of range");
}
}
}