/*
* QR Code generator library (Java)
*
* Copyright (c) Project Nayuki. (MIT License)
* https://www.nayuki.io/page/qr-code-generator-library
*
* 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.List;
import java.util.Objects;
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) {
Objects.requireNonNull(data);
BitBuffer bb = new BitBuffer();
for (byte b : data)
bb.appendBits(b & 0xFF, 8);
return new QrSegment(Mode.BYTE, data.length, bb);
}
/**
* 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) {
Objects.requireNonNull(digits);
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);
}
/**
* 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) {
Objects.requireNonNull(text);
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_CHARSET.indexOf(text.charAt(i)) * 45;
temp += ALPHANUMERIC_CHARSET.indexOf(text.charAt(i + 1));
bb.appendBits(temp, 11);
}
if (i < text.length()) // 1 character remaining
bb.appendBits(ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)), 6);
return new QrSegment(Mode.ALPHANUMERIC, text.length(), bb);
}
/**
* 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) {
Objects.requireNonNull(text);
// Select the most efficient segment encoding automatically
List<QrSegment> result = new ArrayList<>();
if (text.equals("")); // Leave result empty
else if (NUMERIC_REGEX.matcher(text).matches())
result.add(makeNumeric(text));
else if (ALPHANUMERIC_REGEX.matcher(text).matches())
result.add(makeAlphanumeric(text));
else
result.add(makeBytes(text.getBytes(StandardCharsets.UTF_8)));
return result;
}
/**
* Returns a segment representing an Extended Channel Interpretation (ECI) designator with the specified assignment value.
* @param assignVal the ECI assignment number (see the AIM ECI specification)
* @return a segment containing the data
* @throws IllegalArgumentException if the value is outside the range [0, 10<sup>6</sup>)
*/
public static QrSegment makeEci(int assignVal) {
BitBuffer bb = new BitBuffer();
if (0 <= assignVal && assignVal < (1 << 7))
bb.appendBits(assignVal, 8);
else if ((1 << 7) <= assignVal && assignVal < (1 << 14)) {
bb.appendBits(2, 2);
bb.appendBits(assignVal, 14);
} else if ((1 << 14) <= assignVal && assignVal < 1000000) {
bb.appendBits(6, 3);
bb.appendBits(assignVal, 21);
} else
throw new IllegalArgumentException("ECI assignment value out of range");
return new QrSegment(Mode.ECI, 0, bb);
}
/*---- 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 data bits of this segment. Accessed through {@link getBits()}. Not {@code null}. */
final BitBuffer data;
/*---- 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 data the data bits of this segment, which is not {@code null}
* @throws NullPointerException if the mode or bit buffer is {@code null}
* @throws IllegalArgumentException if the character count is negative
*/
public QrSegment(Mode md, int numCh, BitBuffer data) {
Objects.requireNonNull(md);
Objects.requireNonNull(data);
if (numCh < 0)
throw new IllegalArgumentException("Invalid value");
mode = md;
numChars = numCh;
this.data = data.clone(); // Make defensive copy
}
/*---- Methods ----*/
/**
* Returns the data bits of this segment.
* @return the data bits of this segment (not {@code null})
*/
public BitBuffer getBits() {
return data.clone(); // Make defensive copy
}
// Package-private helper function.
static int getTotalBits(List<QrSegment> segs, int version) {
Objects.requireNonNull(segs);
if (version < 1 || version > 40)
throw new IllegalArgumentException("Version number out of range");
long result = 0;
for (QrSegment seg : segs) {
Objects.requireNonNull(seg);
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 += 4L + ccbits + seg.data.bitLength();
if (result > Integer.MAX_VALUE)
return -1;
}
return (int)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 $%*+./:-]*");
/** The set of all legal characters in alphanumeric mode, where each character value maps to the index in the string. */
private static final String ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
/*---- 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),
ECI (0x7, 0, 0, 0);
/*-- Fields --*/
/** An unsigned 4-bit integer value (range 0 to 15) representing the mode indicator bits for this mode object. */
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
*/
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");
}
}
}