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282 lines
10 KiB
282 lines
10 KiB
/*
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* QR Code generator library (Java)
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*
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* Copyright (c) Project Nayuki. (MIT License)
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* https://www.nayuki.io/page/qr-code-generator-library
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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* - The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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* - The Software is provided "as is", without warranty of any kind, express or
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* implied, including but not limited to the warranties of merchantability,
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* fitness for a particular purpose and noninfringement. In no event shall the
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* authors or copyright holders be liable for any claim, damages or other
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* liability, whether in an action of contract, tort or otherwise, arising from,
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* out of or in connection with the Software or the use or other dealings in the
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* Software.
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*/
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package io.nayuki.qrcodegen;
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import java.nio.charset.StandardCharsets;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Objects;
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import java.util.regex.Pattern;
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/**
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* Represents a character string to be encoded in a QR Code symbol. Each segment has
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* a mode, and a sequence of characters that is already encoded as a sequence of bits.
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* Instances of this class are immutable.
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* <p>This segment class imposes no length restrictions, but QR Codes have restrictions.
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* Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
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* Any segment longer than this is meaningless for the purpose of generating QR Codes.</p>
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*/
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public final class QrSegment {
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/*---- Static factory functions ----*/
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/**
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* Returns a segment representing the specified binary data encoded in byte mode.
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* @param data the binary data
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* @return a segment containing the data
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* @throws NullPointerException if the array is {@code null}
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*/
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public static QrSegment makeBytes(byte[] data) {
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Objects.requireNonNull(data);
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BitBuffer bb = new BitBuffer();
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for (byte b : data)
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bb.appendBits(b & 0xFF, 8);
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return new QrSegment(Mode.BYTE, data.length, bb);
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}
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/**
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* Returns a segment representing the specified string of decimal digits encoded in numeric mode.
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* @param digits a string consisting of digits from 0 to 9
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* @return a segment containing the data
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* @throws NullPointerException if the string is {@code null}
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* @throws IllegalArgumentException if the string contains non-digit characters
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*/
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public static QrSegment makeNumeric(String digits) {
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Objects.requireNonNull(digits);
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if (!NUMERIC_REGEX.matcher(digits).matches())
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throw new IllegalArgumentException("String contains non-numeric characters");
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BitBuffer bb = new BitBuffer();
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int i;
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for (i = 0; i <= digits.length() - 3; i += 3) // Process groups of 3
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bb.appendBits(Integer.parseInt(digits.substring(i, i + 3)), 10);
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int rem = digits.length() - i;
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if (rem > 0) // 1 or 2 digits remaining
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bb.appendBits(Integer.parseInt(digits.substring(i)), rem * 3 + 1);
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return new QrSegment(Mode.NUMERIC, digits.length(), bb);
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}
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/**
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* Returns a segment representing the specified text string encoded in alphanumeric mode.
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* The characters allowed are: 0 to 9, A to Z (uppercase only), space,
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* dollar, percent, asterisk, plus, hyphen, period, slash, colon.
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* @param text a string of text, with only certain characters allowed
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* @return a segment containing the data
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* @throws NullPointerException if the string is {@code null}
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* @throws IllegalArgumentException if the string contains non-encodable characters
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*/
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public static QrSegment makeAlphanumeric(String text) {
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Objects.requireNonNull(text);
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if (!ALPHANUMERIC_REGEX.matcher(text).matches())
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throw new IllegalArgumentException("String contains unencodable characters in alphanumeric mode");
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BitBuffer bb = new BitBuffer();
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int i;
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for (i = 0; i <= text.length() - 2; i += 2) { // Process groups of 2
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int temp = ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)) * 45;
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temp += ALPHANUMERIC_CHARSET.indexOf(text.charAt(i + 1));
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bb.appendBits(temp, 11);
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}
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if (i < text.length()) // 1 character remaining
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bb.appendBits(ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)), 6);
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return new QrSegment(Mode.ALPHANUMERIC, text.length(), bb);
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}
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/**
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* Returns a new mutable list of zero or more segments to represent the specified Unicode text string.
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* The result may use various segment modes and switch modes to optimize the length of the bit stream.
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* @param text the text to be encoded, which can be any Unicode string
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* @return a list of segments containing the text
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* @throws NullPointerException if the text is {@code null}
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*/
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public static List<QrSegment> makeSegments(String text) {
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Objects.requireNonNull(text);
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// Select the most efficient segment encoding automatically
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List<QrSegment> result = new ArrayList<>();
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if (text.equals("")); // Leave result empty
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else if (NUMERIC_REGEX.matcher(text).matches())
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result.add(makeNumeric(text));
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else if (ALPHANUMERIC_REGEX.matcher(text).matches())
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result.add(makeAlphanumeric(text));
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else
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result.add(makeBytes(text.getBytes(StandardCharsets.UTF_8)));
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return result;
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}
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/**
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* Returns a segment representing an Extended Channel Interpretation
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* (ECI) designator with the specified assignment value.
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* @param assignVal the ECI assignment number (see the AIM ECI specification)
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* @return a segment containing the data
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* @throws IllegalArgumentException if the value is outside the range [0, 10<sup>6</sup>)
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*/
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public static QrSegment makeEci(int assignVal) {
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BitBuffer bb = new BitBuffer();
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if (0 <= assignVal && assignVal < (1 << 7))
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bb.appendBits(assignVal, 8);
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else if ((1 << 7) <= assignVal && assignVal < (1 << 14)) {
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bb.appendBits(2, 2);
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bb.appendBits(assignVal, 14);
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} else if ((1 << 14) <= assignVal && assignVal < 1000000) {
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bb.appendBits(6, 3);
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bb.appendBits(assignVal, 21);
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} else
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throw new IllegalArgumentException("ECI assignment value out of range");
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return new QrSegment(Mode.ECI, 0, bb);
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}
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/*---- Instance fields ----*/
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/** The mode indicator for this segment. Never {@code null}. */
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public final Mode mode;
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/** The length of this segment's unencoded data, measured in characters. Always zero or positive. */
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public final int numChars;
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/** The data bits of this segment. Accessed through {@link getBits()}. Not {@code null}. */
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final BitBuffer data;
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/*---- Constructor ----*/
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/**
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* Constructs a QR Code data segment with the specified parameters and data.
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* @param md the mode, which is not {@code null}
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* @param numCh the data length in characters, which is non-negative
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* @param data the data bits of this segment, which is not {@code null}
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* @throws NullPointerException if the mode or bit buffer is {@code null}
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* @throws IllegalArgumentException if the character count is negative
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*/
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public QrSegment(Mode md, int numCh, BitBuffer data) {
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mode = Objects.requireNonNull(md);
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Objects.requireNonNull(data);
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if (numCh < 0)
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throw new IllegalArgumentException("Invalid value");
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numChars = numCh;
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this.data = data.clone(); // Make defensive copy
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}
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/*---- Methods ----*/
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/**
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* Returns the data bits of this segment.
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* @return the data bits of this segment (not {@code null})
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*/
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public BitBuffer getBits() {
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return data.clone(); // Make defensive copy
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}
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// Calculates the number of bits needed to encode the given segments at the given version.
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// Returns a non-negative number if successful. Otherwise returns -1 if a segment has too
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// many characters to fit its length field, or the total bits exceeds Integer.MAX_VALUE.
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static int getTotalBits(List<QrSegment> segs, int version) {
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Objects.requireNonNull(segs);
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long result = 0;
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for (QrSegment seg : segs) {
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Objects.requireNonNull(seg);
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int ccbits = seg.mode.numCharCountBits(version);
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if (seg.numChars >= (1 << ccbits))
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return -1; // The segment's length doesn't fit the field's bit width
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result += 4L + ccbits + seg.data.bitLength();
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if (result > Integer.MAX_VALUE)
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return -1; // The sum will overflow an int type
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}
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return (int)result;
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}
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/*---- Constants ----*/
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/** Can test whether a string is encodable in numeric mode (such as by using {@link #makeNumeric(String)}). */
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public static final Pattern NUMERIC_REGEX = Pattern.compile("[0-9]*");
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/** Can test whether a string is encodable in alphanumeric mode (such as by using {@link #makeAlphanumeric(String)}). */
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public static final Pattern ALPHANUMERIC_REGEX = Pattern.compile("[A-Z0-9 $%*+./:-]*");
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/** The set of all legal characters in alphanumeric mode, where each character value maps to the index in the string. */
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private static final String ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
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/*---- Public helper enumeration ----*/
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/**
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* The mode field of a segment. Immutable. Provides methods to retrieve closely related values.
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*/
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public enum Mode {
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/*-- Constants --*/
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NUMERIC (0x1, 10, 12, 14),
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ALPHANUMERIC(0x2, 9, 11, 13),
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BYTE (0x4, 8, 16, 16),
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KANJI (0x8, 8, 10, 12),
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ECI (0x7, 0, 0, 0);
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/*-- Fields --*/
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/** An unsigned 4-bit integer value (range 0 to 15) representing the mode indicator bits for this mode object. */
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final int modeBits;
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private final int[] numBitsCharCount;
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/*-- Constructor --*/
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private Mode(int mode, int... ccbits) {
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modeBits = mode;
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numBitsCharCount = ccbits;
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}
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/*-- Method --*/
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/**
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* Returns the bit width of the segment character count field for this mode object at the specified version number.
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* @param ver the version number, which is between 1 to 40 (inclusive)
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* @return the number of bits for the character count, which is between 8 to 16 (inclusive)
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* @throws IllegalArgumentException if the version number is out of range
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*/
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int numCharCountBits(int ver) {
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if ( 1 <= ver && ver <= 9) return numBitsCharCount[0];
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else if (10 <= ver && ver <= 26) return numBitsCharCount[1];
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else if (27 <= ver && ver <= 40) return numBitsCharCount[2];
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else throw new IllegalArgumentException("Version number out of range");
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}
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}
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}
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