Added Python port of the library, updated comments and tweaked code in Java and JavaScript versions.
This commit is contained in:
Nayuki Minase
parent
72921ece29
commit
3c6cc5eabc
45
QrCode.java
45
QrCode.java
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@ -53,17 +53,30 @@ public final class QrCode {
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public static QrCode encodeText(String text, Ecc ecl) {
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if (text == null || ecl == null)
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throw new NullPointerException();
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QrSegment seg; // Select the most efficient segment encoding automatically
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if (QrSegment.NUMERIC_REGEX.matcher(text).matches())
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seg = QrSegment.makeNumeric(text);
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else if (QrSegment.ALPHANUMERIC_REGEX.matcher(text).matches())
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seg = QrSegment.makeAlphanumeric(text);
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else
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seg = QrSegment.makeBytes(text.getBytes(StandardCharsets.UTF_8));
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QrSegment seg = encodeTextToSegment(text);
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return encodeSegments(Arrays.asList(seg), ecl);
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}
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/**
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* Returns a QR Code segment representing the specified Unicode text string.
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* @param text the text to be encoded, which can be any Unicode string
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* @return a QR Code representing the text
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* @throws NullPointerException if the text is {@code null}
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*/
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public static QrSegment encodeTextToSegment(String text) {
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if (text == null)
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throw new NullPointerException();
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// Select the most efficient segment encoding automatically
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if (QrSegment.NUMERIC_REGEX.matcher(text).matches())
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return QrSegment.makeNumeric(text);
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else if (QrSegment.ALPHANUMERIC_REGEX.matcher(text).matches())
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return QrSegment.makeAlphanumeric(text);
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else
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return QrSegment.makeBytes(text.getBytes(StandardCharsets.UTF_8));
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}
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/**
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* Returns a QR Code symbol representing the specified binary data string at the specified error correction level.
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* This function always encodes using the binary segment mode, not any text mode. The maximum number of
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@ -255,10 +268,10 @@ public final class QrCode {
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* @return the module's color, which is either 0 (white) or 1 (black)
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*/
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public int getModule(int x, int y) {
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if (x < 0 || x >= size || y < 0 || y >= size)
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return 0; // Infinite white border
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else
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if (0 <= x && x < size && 0 <= y && y < size)
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return modules[y][x] ? 1 : 0;
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else
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return 0; // Infinite white border
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}
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@ -353,7 +366,7 @@ public final class QrCode {
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// Draws two copies of the format bits (with its own error correction code)
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// based on this object's error correction level and mask fields.
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// based on the given mask and this object's error correction level field.
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private void drawFormatBits(int mask) {
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// Calculate error correction code and pack bits
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int data = errorCorrectionLevel.formatBits << 3 | mask; // errCorrLvl is uint2, mask is uint3
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@ -400,8 +413,9 @@ public final class QrCode {
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// Draw two copies
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for (int i = 0; i < 18; i++) {
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boolean bit = ((data >>> i) & 1) != 0;
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setFunctionModule(size - 11 + i % 3, i / 3, bit);
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setFunctionModule(i / 3, size - 11 + i % 3, bit);
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int a = size - 11 + i % 3, b = i / 3;
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setFunctionModule(a, b, bit);
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setFunctionModule(b, a, bit);
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}
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}
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@ -411,8 +425,7 @@ public final class QrCode {
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for (int i = -4; i <= 4; i++) {
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for (int j = -4; j <= 4; j++) {
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int dist = Math.max(Math.abs(i), Math.abs(j)); // Chebyshev/infinity norm
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int xx = x + j;
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int yy = y + i;
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int xx = x + j, yy = y + i;
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if (0 <= xx && xx < size && 0 <= yy && yy < size)
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setFunctionModule(xx, yy, dist != 2 && dist != 4);
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}
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@ -495,7 +508,7 @@ public final class QrCode {
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boolean upwards = ((right & 2) == 0) ^ (x < 6);
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int y = upwards ? size - 1 - vert : vert; // Actual y coordinate
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if (!isFunction[y][x] && i < data.length * 8) {
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modules[y][x] = (data[i >>> 3] >>> (7 - (i & 7)) & 1) != 0;
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modules[y][x] = ((data[i >>> 3] >>> (7 - (i & 7))) & 1) != 0;
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i++;
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}
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}
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@ -0,0 +1,125 @@
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#
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# QR Code generator demo (Python 2, 3)
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#
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# Copyright (c) 2016 Project Nayuki
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# https://www.nayuki.io/page/qr-code-generator-library
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#
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# (MIT License)
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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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from __future__ import print_function
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import qrcodegen
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# ---- Main program ----
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def main():
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"""The main application program."""
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do_basic_demo()
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do_variety_demo()
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do_segment_demo()
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def do_basic_demo():
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"""Creates a single QR Code, then prints it to the console."""
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text = u"Hello, world!" # User-supplied Unicode text
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errcorlvl = qrcodegen.QrCode.Ecc.LOW # Error correction level
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qr = qrcodegen.encode_text(text, errcorlvl)
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print_qr(qr)
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def do_variety_demo():
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"""Creates a variety of QR Codes that exercise different features of the library, and prints each one to the console."""
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# Project Nayuki URL
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qr = qrcodegen.encode_text("https://www.nayuki.io/", qrcodegen.QrCode.Ecc.HIGH)
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qr = qrcodegen.QrCode(qrcode=qr, mask=3) # Change mask, forcing to mask #3
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print_qr(qr)
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# Numeric mode encoding (3.33 bits per digit)
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qr = qrcodegen.encode_text("314159265358979323846264338327950288419716939937510", qrcodegen.QrCode.Ecc.MEDIUM)
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print_qr(qr)
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# Alphanumeric mode encoding (5.5 bits per character)
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qr = qrcodegen.encode_text("DOLLAR-AMOUNT:$39.87 PERCENTAGE:100.00% OPERATIONS:+-*/", qrcodegen.QrCode.Ecc.HIGH)
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print_qr(qr)
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# Unicode text as UTF-8, and different masks
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qr = qrcodegen.encode_text(u"\u3053\u3093\u306B\u3061\u0077\u0061\u3001\u4E16\u754C\uFF01\u0020\u03B1\u03B2\u03B3\u03B4", qrcodegen.QrCode.Ecc.QUARTILE)
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print_qr(qrcodegen.QrCode(qrcode=qr, mask=0))
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print_qr(qrcodegen.QrCode(qrcode=qr, mask=1))
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print_qr(qrcodegen.QrCode(qrcode=qr, mask=5))
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print_qr(qrcodegen.QrCode(qrcode=qr, mask=7))
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# Moderately large QR Code using longer text (from Lewis Carroll's Alice in Wonderland)
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qr = qrcodegen.encode_text("Alice was beginning to get very tired of sitting by her sister on the bank, "
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"and of having nothing to do: once or twice she had peeped into the book her sister was reading, "
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"but it had no pictures or conversations in it, 'and what is the use of a book,' thought Alice "
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"'without pictures or conversations?' So she was considering in her own mind (as well as she could, "
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"for the hot day made her feel very sleepy and stupid), whether the pleasure of making a "
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"daisy-chain would be worth the trouble of getting up and picking the daisies, when suddenly "
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"a White Rabbit with pink eyes ran close by her.", qrcodegen.QrCode.Ecc.HIGH)
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print_qr(qr)
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def do_segment_demo():
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"""Creates QR Codes with manually specified segments for better compactness."""
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# Illustration "silver"
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silver0 = "THE SQUARE ROOT OF 2 IS 1."
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silver1 = "41421356237309504880168872420969807856967187537694807317667973799"
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qr = qrcodegen.encode_text(silver0 + silver1, qrcodegen.QrCode.Ecc.LOW)
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print_qr(qr)
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segs = [
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qrcodegen.QrSegment.make_alphanumeric(silver0),
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qrcodegen.QrSegment.make_numeric(silver1)]
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qr = qrcodegen.encode_segments(segs, qrcodegen.QrCode.Ecc.LOW)
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print_qr(qr)
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# Illustration "golden"
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golden0 = u"Golden ratio \u03C6 = 1."
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golden1 = u"6180339887498948482045868343656381177203091798057628621354486227052604628189024497072072041893911374"
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golden2 = u"......"
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qr = qrcodegen.encode_text(golden0 + golden1 + golden2, qrcodegen.QrCode.Ecc.LOW)
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print_qr(qr)
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segs = [
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qrcodegen.QrSegment.make_bytes(golden0.encode("UTF-8")),
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qrcodegen.QrSegment.make_numeric(golden1),
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qrcodegen.QrSegment.make_alphanumeric(golden2)]
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qr = qrcodegen.encode_segments(segs, qrcodegen.QrCode.Ecc.LOW)
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print_qr(qr)
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# ---- Utilities ----
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def print_qr(qrcode):
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"""Prints the given QrCode object to the console."""
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border = 4
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for y in range(-border, qrcode.get_size() + border):
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for x in range(-border, qrcode.get_size() + border):
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print(u"\u2588 "[qrcode.get_module(x,y)] * 2, end="")
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print()
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print()
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# Run the main program
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if __name__ == "__main__":
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main()
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92
qrcodegen.js
92
qrcodegen.js
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@ -27,16 +27,16 @@
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/*
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* Module "qrcodegen". Public members inside this namespace:
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* - Function encodeText(str text, Ecc ecl) -> QrCode
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* - Function encodeText(str text, QrCode.Ecc ecl) -> QrCode
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* - Function encodeTextToSegment(str text) -> QrSegment
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* - Function encodeBinary(list<int> data, Ecc ecl) -> QrCode
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* - Function encodeSegments(list<QrSegment> segs, Ecc ecl) -> QrCode
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* - Function encodeBinary(list<int> data, QrCode.Ecc ecl) -> QrCode
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* - Function encodeSegments(list<QrSegment> segs, QrCode.Ecc ecl) -> QrCode
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* - Class QrCode:
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* - Constructor QrCode(QrCode qr, int mask)
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* - Constructor QrCode(list<int> bytes, int mask, int version, Ecc ecl)
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* - Constructor QrCode(list<int> bytes, int mask, int version, QrCode.Ecc ecl)
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* - Method getVersion() -> int
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* - Method getSize() -> int
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* - Method getErrorCorrectionLevel() -> Ecc
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* - Method getErrorCorrectionLevel() -> QrCode.Ecc
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* - Method getMask() -> int
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* - Method getModule(int x, int y) -> int
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* - Method isFunctionModule(int x, int y) -> bool
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@ -48,8 +48,8 @@
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* - Function makeBytes(list<int> data) -> QrSegment
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* - Function makeNumeric(str data) -> QrSegment
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* - Function makeAlphanumeric(str data) -> QrSegment
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* - Constructor QrSegment(Mode mode, int numChars, list<int> bitData)
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* - Method getMode() -> Mode
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* - Constructor QrSegment(QrSegment.Mode mode, int numChars, list<int> bitData)
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* - Method getMode() -> QrSegment.Mode
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* - Method getNumChars() -> int
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* - Method getBits() -> list<int>
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* - Enum Mode:
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@ -155,11 +155,13 @@ var qrcodegen = new function() {
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/*---- QR Code symbol class ----*/
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/*
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* A class that represents an immutable square grid of black and white cells for a QR Code symbol,
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* with associated static functions to create a QR Code from user-supplied textual or binary data.
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* This class covers the QR Code model 2 specification, supporting all versions (sizes)
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* from 1 to 40, all 4 error correction levels, and only 3 character encoding modes.
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* from 1 to 40, all 4 error correction levels.
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*
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* This constructor can be called in one of two ways:
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* - new QrCode(bytes, mask, version, errCorLvl):
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@ -179,17 +181,15 @@ var qrcodegen = new function() {
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// Handle simple scalar fields
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if (mask < -1 || mask > 7)
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throw "Mask value out of range";
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var size;
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if (initData instanceof Array) {
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if (version < 1 || version > 40)
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throw "Version value out of range";
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size = version * 4 + 17;
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} else if (initData instanceof qrcodegen.QrCode) {
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version = initData.getVersion();
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size = initData.getSize();
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errCorLvl = initData.getErrorCorrectionLevel();
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} else
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throw "Invalid initial data";
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var size = version * 4 + 17;
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// Initialize both grids to be size*size arrays of Boolean false
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var row = [];
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@ -204,7 +204,7 @@ var qrcodegen = new function() {
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// Handle grid fields
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if (initData instanceof Array) {
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// Draw function patterns, draw all codewords, do masking
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// Draw function patterns, draw all codewords
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drawFunctionPatterns();
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var allCodewords = appendErrorCorrection(initData);
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drawCodewords(allCodewords);
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@ -267,19 +267,19 @@ var qrcodegen = new function() {
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// Returns the color of the module (pixel) at the given coordinates, which is either 0 for white or 1 for black. The top
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// left corner has the coordinates (x=0, y=0). If the given coordinates are out of bounds, then 0 (white) is returned.
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this.getModule = function(x, y) {
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if (x < 0 || x >= size || y < 0 || y >= size)
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return 0; // Infinite white border
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else
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if (0 <= x && x < size && 0 <= y && y < size)
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return modules[y][x] ? 1 : 0;
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else
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return 0; // Infinite white border
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};
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// Tests whether the module at the given coordinates is a function module (true) or not (false). The top left
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// corner has the coordinates (x=0, y=0). If the given coordinates are out of bounds, then false is returned.
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this.isFunctionModule = function(x, y) {
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if (x < 0 || x >= size || y < 0 || y >= size)
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return false; // Infinite border
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else
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if (0 <= x && x < size && 0 <= y && y < size)
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return isFunction[y][x];
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else
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return false; // Infinite border
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};
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@ -345,7 +345,7 @@ var qrcodegen = new function() {
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// Draws two copies of the format bits (with its own error correction code)
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// based on this object's error correction level and mask fields.
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// based on the given mask and this object's error correction level field.
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function drawFormatBits(mask) {
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// Calculate error correction code and pack bits
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var data = errCorLvl.formatBits << 3 | mask; // errCorrLvl is uint2, mask is uint3
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@ -392,8 +392,7 @@ var qrcodegen = new function() {
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// Draw two copies
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for (var i = 0; i < 18; i++) {
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var bit = ((data >>> i) & 1) != 0;
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var a = size - 11 + i % 3;
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var b = Math.floor(i / 3);
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var a = size - 11 + i % 3, b = Math.floor(i / 3);
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setFunctionModule(a, b, bit);
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setFunctionModule(b, a, bit);
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}
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@ -405,8 +404,7 @@ var qrcodegen = new function() {
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for (var i = -4; i <= 4; i++) {
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for (var j = -4; j <= 4; j++) {
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var dist = Math.max(Math.abs(i), Math.abs(j)); // Chebyshev/infinity norm
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var xx = x + j;
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var yy = y + i;
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var xx = x + j, yy = y + i;
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if (0 <= xx && xx < size && 0 <= yy && yy < size)
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setFunctionModule(xx, yy, dist != 2 && dist != 4);
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}
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@ -489,7 +487,7 @@ var qrcodegen = new function() {
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var upwards = ((right & 2) == 0) ^ (x < 6);
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var y = upwards ? size - 1 - vert : vert; // Actual y coordinate
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if (!isFunction[y][x] && i < data.length * 8) {
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modules[y][x] = (data[i >>> 3] >>> (7 - (i & 7)) & 1) != 0;
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modules[y][x] = ((data[i >>> 3] >>> (7 - (i & 7))) & 1) != 0;
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i++;
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}
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}
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@ -614,9 +612,9 @@ var qrcodegen = new function() {
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var QrCode = {}; // Private object to assign properties to
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// Returns a set of positions of the alignment patterns in ascending order. These positions are
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// used on both the x and y axes. Each value in the resulting array is in the range [0, 177).
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// This stateless pure function could be implemented as table of 40 variable-length lists of unsigned bytes.
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// Returns a sequence of positions of the alignment patterns in ascending order. These positions are
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// used on both the x and y axes. Each value in the resulting sequence is in the range [0, 177).
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// This stateless pure function could be implemented as table of 40 variable-length lists of integers.
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QrCode.getAlignmentPatternPositions = function(ver) {
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if (ver < 1 || ver > 40)
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throw "Version number out of range";
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@ -705,6 +703,8 @@ var qrcodegen = new function() {
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/*---- Data segment class ----*/
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/*
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* A public class that represents a character string to be encoded in a QR Code symbol.
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* Each segment has a mode, and a sequence of characters that is already encoded as
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@ -714,6 +714,9 @@ var qrcodegen = new function() {
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* Any segment longer than this is meaningless for the purpose of generating QR Codes.
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*/
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this.QrSegment = function(mode, numChars, bitData) {
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if (numChars < 0 || !(mode instanceof Mode))
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throw "Invalid argument";
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|
||||
/*-- Accessor methods --*/
|
||||
this.getMode = function() {
|
||||
return mode;
|
||||
|
|
@ -726,7 +729,7 @@ var qrcodegen = new function() {
|
|||
};
|
||||
};
|
||||
|
||||
/*-- Static factory functions --*/
|
||||
/*-- Public static factory functions --*/
|
||||
|
||||
// Returns a segment representing the given binary data encoded in byte mode.
|
||||
this.QrSegment.makeBytes = function(data) {
|
||||
|
|
@ -819,37 +822,16 @@ var qrcodegen = new function() {
|
|||
|
||||
// Returns a new array of bytes representing the given string encoded in UTF-8.
|
||||
function toUtf8ByteArray(str) {
|
||||
str = encodeURI(str);
|
||||
var result = [];
|
||||
for (var i = 0; i < str.length; i++) {
|
||||
var c = str.charCodeAt(i);
|
||||
if (c < 0x80)
|
||||
result.push(c);
|
||||
else if (c < 0x800) {
|
||||
result.push(0xC0 | ((c >>> 6) & 0x1F));
|
||||
result.push(0x80 | ((c >>> 0) & 0x3F));
|
||||
} else if (0xD800 <= c && c < 0xDC00) { // High surrogate
|
||||
i++;
|
||||
if (i < str.length) {
|
||||
var d = str.charCodeAt(i);
|
||||
if (0xDC00 <= d && d < 0xE000) { // Low surrogate
|
||||
c = ((c & 0x3FF) << 10 | (d & 0x3FF)) + 0x10000;
|
||||
result.push(0xF0 | ((c >>> 18) & 0x07));
|
||||
result.push(0x80 | ((c >>> 12) & 0x3F));
|
||||
result.push(0x80 | ((c >>> 6) & 0x3F));
|
||||
result.push(0x80 | ((c >>> 0) & 0x3F));
|
||||
continue;
|
||||
if (str.charAt(i) != "%")
|
||||
result.push(str.charCodeAt(i));
|
||||
else {
|
||||
result.push(parseInt(str.substr(i + 1, 2), 16));
|
||||
i += 2;
|
||||
}
|
||||
}
|
||||
throw "Invalid UTF-16 string";
|
||||
} else if (0xDC00 <= c && c < 0xE000) // Low surrogate
|
||||
throw "Invalid UTF-16 string";
|
||||
else if (c < 0x10000) {
|
||||
result.push(0xE0 | ((c >>> 12) & 0x0F));
|
||||
result.push(0x80 | ((c >>> 6) & 0x3F));
|
||||
result.push(0x80 | ((c >>> 0) & 0x3F));
|
||||
} else
|
||||
throw "Assertion error";
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,813 @@
|
|||
#
|
||||
# QR Code generator library (Python 2, 3)
|
||||
#
|
||||
# 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.
|
||||
#
|
||||
|
||||
import itertools, re, sys
|
||||
|
||||
|
||||
"""
|
||||
Public members inside this module "qrcodegen":
|
||||
- Function encode_text(str text, QrCode.Ecc ecl) -> QrCode
|
||||
- Function encode_text_to_segment(str text) -> QrSegment
|
||||
- Function encode_binary(bytes data, QrCode.Ecc ecl) -> QrCode
|
||||
- Function encode_segments(list<QrSegment> segs, QrCode.Ecc ecl) -> QrCode
|
||||
- Class QrCode:
|
||||
- Constructor QrCode(QrCode qr, int mask)
|
||||
- Constructor QrCode(bytes bytes, int mask, int version, QrCode.Ecc ecl)
|
||||
- Method get_version() -> int
|
||||
- Method get_size() -> int
|
||||
- Method get_error_correction_level() -> QrCode.Ecc
|
||||
- Method get_mask() -> int
|
||||
- Method get_module(int x, int y) -> int
|
||||
- Method to_svg_str(int border) -> str
|
||||
- Enum Ecc:
|
||||
- Constants LOW, MEDIUM, QUARTILE, HIGH
|
||||
- Fields int ordinal, formatbits
|
||||
- Class QrSegment:
|
||||
- Function make_bytes(bytes data) -> QrSegment
|
||||
- Function make_numeric(str digits) -> QrSegment
|
||||
- Function make_alphanumeric(str text) -> QrSegment
|
||||
- Constructor QrSegment(QrSegment.Mode mode, int numch, list<int> bitdata)
|
||||
- Method get_mode() -> QrSegment.Mode
|
||||
- Method get_num_chars() -> int
|
||||
- Method get_bits() -> list<int>
|
||||
- Enum Mode:
|
||||
- Constants NUMERIC, ALPHANUMERIC, BYTE, KANJI
|
||||
- Method get_mode_bits() -> int
|
||||
- Method num_char_count_bits(int ver) -> int
|
||||
"""
|
||||
|
||||
|
||||
# ---- Public static factory functions for QrCode ----
|
||||
|
||||
def encode_text(text, ecl):
|
||||
"""Returns a QR Code symbol representing the given Unicode text string at the given error correction level.
|
||||
As a conservative upper bound, this function is guaranteed to succeed for strings that have 738 or fewer Unicode
|
||||
code points (not UTF-16 code units). The smallest possible QR Code version is automatically chosen for the output."""
|
||||
seg = encode_text_to_segment(text)
|
||||
return encode_segments([seg], ecl)
|
||||
|
||||
|
||||
def encode_text_to_segment(text):
|
||||
"""Returns a QR Code segment representing the given Unicode text string."""
|
||||
if not isinstance(text, str) and (sys.version_info[0] >= 3 or not isinstance(text, unicode)):
|
||||
raise TypeError("Text string expected")
|
||||
# Select the most efficient segment encoding automatically
|
||||
if QrSegment.NUMERIC_REGEX.match(text) is not None:
|
||||
return QrSegment.make_numeric(text)
|
||||
elif QrSegment.ALPHANUMERIC_REGEX.match(text) is not None:
|
||||
return QrSegment.make_alphanumeric(text)
|
||||
else:
|
||||
return QrSegment.make_bytes(text.encode("UTF-8"))
|
||||
|
||||
|
||||
def encode_binary(data, ecl):
|
||||
"""Returns a QR Code symbol representing the given binary data string at the given error correction level.
|
||||
This function always encodes using the binary segment mode, not any text mode. The maximum number of
|
||||
bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output."""
|
||||
if not isinstance(data, bytes):
|
||||
raise TypeError("Binary array expected")
|
||||
return QrCode.encode_segments([QrSegment.make_bytes(data)], ecl)
|
||||
|
||||
|
||||
def encode_segments(segs, ecl):
|
||||
"""Returns a QR Code symbol representing the given data segments at the given error
|
||||
correction level. The smallest possible QR Code version is automatically chosen for the output.
|
||||
This function allows the user to create a custom sequence of segments that switches
|
||||
between modes (such as alphanumeric and binary) to encode text more efficiently. This
|
||||
function is considered to be lower level than simply encoding text or binary data."""
|
||||
|
||||
# Find the minimal version number to use
|
||||
for version in itertools.count(1): # Increment until the data fits in the QR Code
|
||||
if version > 40: # All versions could not fit the given data
|
||||
raise ValueError("Data too long")
|
||||
datacapacitybits = QrCode._get_num_data_codewords(version, ecl) * 8 # Number of data bits available
|
||||
|
||||
# Calculate the total number of bits needed at this version number
|
||||
# to encode all the segments (i.e. segment metadata and payloads)
|
||||
datausedbits = 0
|
||||
for seg in segs:
|
||||
if seg.get_num_chars() < 0:
|
||||
raise AssertionError()
|
||||
ccbits = seg.get_mode().num_char_count_bits(version)
|
||||
if seg.get_num_chars() >= (1 << ccbits):
|
||||
# Segment length value doesn't fit in the length field's bit-width, so fail immediately
|
||||
break
|
||||
datausedbits += 4 + ccbits + len(seg.get_bits())
|
||||
else: # If the loop above did not break
|
||||
if datausedbits <= datacapacitybits:
|
||||
break # This version number is found to be suitable
|
||||
|
||||
# Create the data bit string by concatenating all segments
|
||||
bb = _BitBuffer()
|
||||
for seg in segs:
|
||||
bb.append_bits(seg.get_mode().get_mode_bits(), 4)
|
||||
bb.append_bits(seg.get_num_chars(), seg.get_mode().num_char_count_bits(version))
|
||||
bb.append_all(seg)
|
||||
|
||||
# Add terminator and pad up to a byte if applicable
|
||||
bb.append_bits(0, min(4, datacapacitybits - bb.bit_length()))
|
||||
bb.append_bits(0, -bb.bit_length() % 8)
|
||||
|
||||
# Pad with alternate bytes until data capacity is reached
|
||||
for padbyte in itertools.cycle((0xEC, 0x11)):
|
||||
if bb.bit_length() >= datacapacitybits:
|
||||
break
|
||||
bb.append_bits(padbyte, 8)
|
||||
assert bb.bit_length() % 8 == 0
|
||||
|
||||
# Create the QR Code symbol
|
||||
return QrCode(datacodewords=bb.get_bytes(), mask=-1, version=version, errcorlvl=ecl)
|
||||
|
||||
|
||||
|
||||
# ---- QR Code symbol class ----
|
||||
|
||||
class QrCode(object):
|
||||
"""Represents an immutable square grid of black or white cells for a QR Code symbol. This class covers the
|
||||
QR Code model 2 specification, supporting all versions (sizes) from 1 to 40, all 4 error correction levels."""
|
||||
|
||||
# ---- Constructor ----
|
||||
|
||||
def __init__(self, qrcode=None, datacodewords=None, mask=None, version=None, errcorlvl=None):
|
||||
"""This constructor can be called in one of two ways:
|
||||
- QrCode(datacodewords=list<int>, mask=int, version=int, errcorlvl=QrCode.Ecc):
|
||||
Creates a new QR Code symbol with the given version number, error correction level, binary data array,
|
||||
and mask number. This cumbersome constructor can be invoked directly by the user, but is considered
|
||||
to be even lower level than qrcodegen.encode_segments().
|
||||
- QrCode(qrcode=QrCode, mask=int):
|
||||
Creates a new QR Code symbol based on the given existing object, but with a potentially different
|
||||
mask pattern. The version, error correction level, codewords, etc. of the newly created object are
|
||||
all identical to the argument object; only the mask may differ.
|
||||
In both cases, mask = -1 is for automatic choice or 0 to 7 for fixed choice."""
|
||||
|
||||
# Handle simple scalar fields
|
||||
if not -1 <= mask <= 7:
|
||||
raise ValueError("Mask value out of range")
|
||||
if datacodewords is not None and qrcode is None:
|
||||
if not 1 <= version <= 40:
|
||||
raise ValueError("Version value out of range")
|
||||
if not isinstance(errcorlvl, QrCode.Ecc):
|
||||
raise TypeError("QrCode.Ecc expected")
|
||||
elif qrcode is not None and datacodewords is None:
|
||||
version = qrcode._version
|
||||
errcorlvl = qrcode._errcorlvl
|
||||
else:
|
||||
raise ValueError("Exactly one of datacodewords or qrcode must be not None")
|
||||
self._version = version
|
||||
self._errcorlvl = errcorlvl
|
||||
self._size = version * 4 + 17
|
||||
|
||||
if datacodewords is not None: # Render from scratch a QR Code based on data codewords
|
||||
if len(datacodewords) != QrCode._get_num_data_codewords(version, errcorlvl):
|
||||
raise ValueError("Invalid array length")
|
||||
# Initialize grids of modules
|
||||
self._modules = [[False] * self._size for _ in range(self._size)] # The modules of the QR symbol; start with entirely white grid
|
||||
self._isfunction = [[False] * self._size for _ in range(self._size)] # Indicates function modules that are not subjected to masking
|
||||
# Draw function patterns, draw all codewords
|
||||
self._draw_function_patterns()
|
||||
allcodewords = self._append_error_correction(datacodewords)
|
||||
self._draw_codewords(allcodewords)
|
||||
elif qrcode is not None: # Modify the mask of an existing QR Code
|
||||
self._modules = [list(row) for row in qrcode._modules] # Deep copy
|
||||
self._isfunction = qrcode._isfunction # Shallow copy because the data is read-only
|
||||
self._apply_mask(qrcode._mask) # Undo existing mask
|
||||
|
||||
# Handle masking
|
||||
if mask == -1: # Automatically choose best mask
|
||||
minpenalty = 1 << 32
|
||||
for i in range(8):
|
||||
self._draw_format_bits(i)
|
||||
self._apply_mask(i)
|
||||
penalty = self._get_penalty_score()
|
||||
if penalty < minpenalty:
|
||||
mask = i
|
||||
minpenalty = penalty
|
||||
self._apply_mask(i) # Undoes the mask due to XOR
|
||||
assert 0 <= mask <= 7
|
||||
self._draw_format_bits(mask) # Overwrite old format bits
|
||||
self._apply_mask(mask) # Apply the final choice of mask
|
||||
self._mask = mask
|
||||
|
||||
|
||||
# ---- Accessor methods ----
|
||||
|
||||
def get_version(self):
|
||||
"""Returns this QR Code symbol's version number, which is always between 1 and 40 (inclusive)."""
|
||||
return self._version
|
||||
|
||||
def get_size(self):
|
||||
"""Returns the width and height of this QR Code symbol, measured in modules.
|
||||
Always equal to version * 4 + 17, in the range 21 to 177."""
|
||||
return self._size
|
||||
|
||||
def get_error_correction_level(self):
|
||||
"""Returns the error correction level used in this QR Code symbol."""
|
||||
return self._errcorlvl
|
||||
|
||||
def get_mask(self):
|
||||
"""Returns the mask pattern used in this QR Code symbol, in the range 0 to 7 (i.e. unsigned 3-bit integer).
|
||||
Note that even if a constructor was called with automatic masking requested
|
||||
(mask = -1), the resulting object will still have a mask value between 0 and 7."""
|
||||
return self._mask
|
||||
|
||||
def get_module(self, x, y):
|
||||
"""Returns the color of the module (pixel) at the given coordinates, which is either 0 for white or 1 for black. The top
|
||||
left corner has the coordinates (x=0, y=0). If the given coordinates are out of bounds, then 0 (white) is returned."""
|
||||
return 1 if (0 <= x < self._size and 0 <= y < self._size and self._modules[y][x]) else 0
|
||||
|
||||
|
||||
# ---- Public instance methods ----
|
||||
|
||||
def to_svg_str(self, border):
|
||||
"""Based on the given number of border modules to add as padding, this returns a
|
||||
string whose contents represents an SVG XML file that depicts this QR Code symbol."""
|
||||
if border < 0:
|
||||
raise ValueError("Border must be non-negative")
|
||||
parts = []
|
||||
for y in range(-border, self.size + border):
|
||||
for x in range(-border, self.size + border):
|
||||
if self.get_module(x, y) == 1:
|
||||
parts.append("M{},{}h1v1h-1z".format(x + border, y + border))
|
||||
return """<?xml version="1.0" encoding="UTF-8"?>
|
||||
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
|
||||
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" viewBox="0 0 {0} {0}">
|
||||
<path d="{1}" fill="#000000" stroke-width="0"/>
|
||||
</svg>
|
||||
""".format(self.size + border * 2, " ".join(parts))
|
||||
|
||||
|
||||
# ---- Private helper methods for constructor: Drawing function modules ----
|
||||
|
||||
def _draw_function_patterns(self):
|
||||
# Draw the horizontal and vertical timing patterns
|
||||
for i in range(self._size):
|
||||
self._set_function_module(6, i, i % 2 == 0)
|
||||
self._set_function_module(i, 6, i % 2 == 0)
|
||||
|
||||
# Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
|
||||
self._draw_finder_pattern(3, 3)
|
||||
self._draw_finder_pattern(self._size - 4, 3)
|
||||
self._draw_finder_pattern(3, self._size - 4)
|
||||
|
||||
# Draw the numerous alignment patterns
|
||||
alignpatpos = QrCode._get_alignment_pattern_positions(self._version)
|
||||
numalign = len(alignpatpos)
|
||||
skips = ((0, 0), (0, numalign - 1), (numalign - 1, 0)) # Skip the three finder corners
|
||||
for i in range(numalign):
|
||||
for j in range(numalign):
|
||||
if (i, j) not in skips:
|
||||
self._draw_alignment_pattern(alignpatpos[i], alignpatpos[j])
|
||||
|
||||
# Draw configuration data
|
||||
self._draw_format_bits(0) # Dummy mask value; overwritten later in the constructor
|
||||
self._draw_version()
|
||||
|
||||
|
||||
def _draw_format_bits(self, mask):
|
||||
"""Draws two copies of the format bits (with its own error correction code)
|
||||
based on the given mask and this object's error correction level field."""
|
||||
# Calculate error correction code and pack bits
|
||||
data = self._errcorlvl.formatbits << 3 | mask # errCorrLvl is uint2, mask is uint3
|
||||
rem = data
|
||||
for _ in range(10):
|
||||
rem = (rem << 1) ^ ((rem >> 9) * 0x537)
|
||||
data = data << 10 | rem
|
||||
data ^= 0x5412 # uint15
|
||||
assert data & ((1 << 15) - 1) == data
|
||||
|
||||
# Draw first copy
|
||||
for i in range(0, 6):
|
||||
self._set_function_module(8, i, ((data >> i) & 1) != 0)
|
||||
self._set_function_module(8, 7, ((data >> 6) & 1) != 0)
|
||||
self._set_function_module(8, 8, ((data >> 7) & 1) != 0)
|
||||
self._set_function_module(7, 8, ((data >> 8) & 1) != 0)
|
||||
for i in range(9, 15):
|
||||
self._set_function_module(14 - i, 8, ((data >> i) & 1) != 0)
|
||||
|
||||
# Draw second copy
|
||||
for i in range(0, 8):
|
||||
self._set_function_module(self._size - 1 - i, 8, ((data >> i) & 1) != 0)
|
||||
for i in range(8, 15):
|
||||
self._set_function_module(8, self._size - 15 + i, ((data >> i) & 1) != 0)
|
||||
self._set_function_module(8, self._size - 8, True)
|
||||
|
||||
|
||||
def _draw_version(self):
|
||||
"""Draws two copies of the version bits (with its own error correction code),
|
||||
based on this object's version field (which only has an effect for 7 <= version <= 40)."""
|
||||
if self._version < 7:
|
||||
return
|
||||
|
||||
# Calculate error correction code and pack bits
|
||||
rem = self._version # version is uint6, in the range [7, 40]
|
||||
for _ in range(12):
|
||||
rem = (rem << 1) ^ ((rem >> 11) * 0x1F25)
|
||||
data = self._version << 12 | rem # uint18
|
||||
assert data & ((1 << 18) - 1) == data
|
||||
|
||||
# Draw two copies
|
||||
for i in range(18):
|
||||
bit = ((data >> i) & 1) != 0
|
||||
a, b = self._size - 11 + i % 3, i // 3
|
||||
self._set_function_module(a, b, bit)
|
||||
self._set_function_module(b, a, bit)
|
||||
|
||||
|
||||
def _draw_finder_pattern(self, x, y):
|
||||
"""Draws a 9*9 finder pattern including the border separator, with the center module at (x, y)."""
|
||||
for i in range(-4, 5):
|
||||
for j in range(-4, 5):
|
||||
dist = max(abs(i), abs(j)) # Chebyshev/infinity norm
|
||||
xx, yy = x + j, y + i
|
||||
if 0 <= xx < self._size and 0 <= yy < self._size:
|
||||
self._set_function_module(xx, yy, dist not in (2, 4))
|
||||
|
||||
|
||||
def _draw_alignment_pattern(self, x, y):
|
||||
"""Draws a 5*5 alignment pattern, with the center module at (x, y)."""
|
||||
for i in range(-2, 3):
|
||||
for j in range(-2, 3):
|
||||
self._set_function_module(x + j, y + i, max(abs(i), abs(j)) != 1)
|
||||
|
||||
|
||||
def _set_function_module(self, x, y, isblack):
|
||||
"""Sets the color of a module and marks it as a function module.
|
||||
Only used by the constructor. Coordinates must be in range."""
|
||||
assert type(isblack) is bool
|
||||
self._modules[y][x] = isblack
|
||||
self._isfunction[y][x] = True
|
||||
|
||||
|
||||
# ---- Private helper methods for constructor: Codewords and masking ----
|
||||
|
||||
def _append_error_correction(self, data):
|
||||
"""Returns a new byte string representing the given data with the appropriate error correction
|
||||
codewords appended to it, based on this object's version and error correction level."""
|
||||
version = self._version
|
||||
assert len(data) == QrCode._get_num_data_codewords(version, self._errcorlvl)
|
||||
numblocks = QrCode._NUM_ERROR_CORRECTION_BLOCKS[self._errcorlvl.ordinal][version]
|
||||
numecc = QrCode._NUM_ERROR_CORRECTION_CODEWORDS[self._errcorlvl.ordinal][version]
|
||||
assert numecc % numblocks == 0
|
||||
ecclen = numecc // numblocks
|
||||
numshortblocks = numblocks - QrCode._get_num_raw_data_modules(version) // 8 % numblocks
|
||||
shortblocklen = self._get_num_raw_data_modules(version) // 8 // numblocks
|
||||
|
||||
blocks = []
|
||||
rs = _ReedSolomonGenerator(ecclen)
|
||||
k = 0
|
||||
for i in range(numblocks):
|
||||
dat = data[k : k + shortblocklen - ecclen + (0 if i < numshortblocks else 1)]
|
||||
k += len(dat)
|
||||
ecc = rs.get_remainder(dat)
|
||||
if i < numshortblocks:
|
||||
dat.append(0)
|
||||
dat.extend(ecc)
|
||||
blocks.append(dat)
|
||||
assert k == len(data)
|
||||
|
||||
result = []
|
||||
for i in range(len(blocks[0])):
|
||||
for (j, blk) in enumerate(blocks):
|
||||
if i != shortblocklen - ecclen or j >= numshortblocks:
|
||||
result.append(blk[i])
|
||||
assert len(result) == QrCode._get_num_raw_data_modules(version) // 8
|
||||
return result
|
||||
|
||||
|
||||
def _draw_codewords(self, data):
|
||||
"""Draws the given sequence of 8-bit codewords (data and error correction) onto the entire
|
||||
data area of this QR Code symbol. Function modules need to be marked off before this is called."""
|
||||
assert len(data) == QrCode._get_num_raw_data_modules(self._version) // 8
|
||||
|
||||
i = 0 # Bit index into the data
|
||||
# Do the funny zigzag scan
|
||||
for right in range(self._size - 1, 0, -2): # Index of right column in each column pair
|
||||
if right <= 6:
|
||||
right -= 1
|
||||
for vert in range(self._size): # Vertical counter
|
||||
for j in range(2):
|
||||
x = right - j # Actual x coordinate
|
||||
upwards = ((right & 2) == 0) ^ (x < 6)
|
||||
y = (self._size - 1 - vert) if upwards else vert # Actual y coordinate
|
||||
if not self._isfunction[y][x] and i < len(data) * 8:
|
||||
self._modules[y][x] = ((data[i >> 3] >> (7 - (i & 7))) & 1) != 0
|
||||
i += 1
|
||||
assert i == len(data) * 8
|
||||
|
||||
|
||||
def _apply_mask(self, mask):
|
||||
"""XORs the data modules in this QR Code with the given mask pattern. Due to XOR's mathematical
|
||||
properties, calling applyMask(m) twice with the same value is equivalent to no change at all.
|
||||
This means it is possible to apply a mask, undo it, and try another mask. Note that a final
|
||||
well-formed QR Code symbol needs exactly one mask applied (not zero, not two, etc.)."""
|
||||
if not 0 <= mask <= 7:
|
||||
raise ValueError("Mask value out of range")
|
||||
masker = QrCode._MASK_PATTERNS[mask]
|
||||
for y in range(self._size):
|
||||
for x in range(self._size):
|
||||
self._modules[y][x] ^= (masker(x, y) == 0) and (not self._isfunction[y][x])
|
||||
|
||||
|
||||
def _get_penalty_score(self):
|
||||
"""Calculates and returns the penalty score based on state of this QR Code's current modules.
|
||||
This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score."""
|
||||
result = 0
|
||||
size = self._size
|
||||
modules = self._modules
|
||||
|
||||
# Adjacent modules in row having same color
|
||||
for y in range(size):
|
||||
colorx = modules[y][0]
|
||||
runx = 1
|
||||
for x in range(1, size):
|
||||
if modules[y][x] != colorx:
|
||||
colorx = modules[y][x]
|
||||
runx = 1
|
||||
else:
|
||||
runx += 1
|
||||
if runx == 5:
|
||||
result += QrCode._PENALTY_N1
|
||||
elif runx > 5:
|
||||
result += 1
|
||||
# Adjacent modules in column having same color
|
||||
for x in range(size):
|
||||
colory = modules[0][x]
|
||||
runy = 1
|
||||
for y in range(1, size):
|
||||
if modules[y][x] != colory:
|
||||
colory = modules[y][x]
|
||||
runy = 1
|
||||
else:
|
||||
runy += 1
|
||||
if runy == 5:
|
||||
result += QrCode._PENALTY_N1
|
||||
elif runy > 5:
|
||||
result += 1
|
||||
|
||||
# 2*2 blocks of modules having same color
|
||||
for y in range(size - 1):
|
||||
for x in range(size - 1):
|
||||
color = modules[y][x]
|
||||
if color == modules[y][x + 1] == modules[y + 1][x] == modules[y + 1][x + 1]:
|
||||
result += QrCode._PENALTY_N2
|
||||
|
||||
# Finder-like pattern in rows
|
||||
for y in range(size):
|
||||
bits = 0
|
||||
for x in range(size):
|
||||
bits = ((bits << 1) & 0x7FF) | (1 if modules[y][x] else 0)
|
||||
if x >= 10 and bits in (0x05D, 0x5D0): # Needs 11 bits accumulated
|
||||
result += QrCode._PENALTY_N3
|
||||
# Finder-like pattern in columns
|
||||
for x in range(size):
|
||||
bits = 0
|
||||
for y in range(size):
|
||||
bits = ((bits << 1) & 0x7FF) | (1 if modules[y][x] else 0)
|
||||
if y >= 10 and bits in (0x05D, 0x5D0): # Needs 11 bits accumulated
|
||||
result += QrCode._PENALTY_N3
|
||||
|
||||
# Balance of black and white modules
|
||||
black = 0
|
||||
for row in modules:
|
||||
for color in row:
|
||||
if color:
|
||||
black += 1
|
||||
total = size**2
|
||||
# Find smallest k such that (45-5k)% <= dark/total <= (55+5k)%
|
||||
for k in itertools.count():
|
||||
if (9-k)*total <= black*20 <= (11+k)*total:
|
||||
break
|
||||
result += QrCode._PENALTY_N4
|
||||
return result
|
||||
|
||||
|
||||
# ---- Private static helper functions ----
|
||||
|
||||
@staticmethod
|
||||
def _get_alignment_pattern_positions(ver):
|
||||
"""Returns a sequence of positions of the alignment patterns in ascending order. These positions are
|
||||
used on both the x and y axes. Each value in the resulting sequence is in the range [0, 177).
|
||||
This stateless pure function could be implemented as table of 40 variable-length lists of integers."""
|
||||
if not 1 <= ver <= 40:
|
||||
raise ValueError("Version number out of range")
|
||||
elif ver == 1:
|
||||
return []
|
||||
else:
|
||||
numalign = ver // 7 + 2
|
||||
if ver != 32:
|
||||
step = (ver * 4 + numalign * 2 + 1) // (2 * numalign - 2) * 2 # ceil((size - 13) / (2*numalign - 2)) * 2
|
||||
else: # C-C-C-Combo breaker!
|
||||
step = 26
|
||||
result = [6] + [None] * (numalign - 1)
|
||||
pos = ver * 4 + 10
|
||||
for i in reversed(range(1, numalign)):
|
||||
result[i] = pos
|
||||
pos -= step
|
||||
return result
|
||||
|
||||
|
||||
@staticmethod
|
||||
def _get_num_raw_data_modules(ver):
|
||||
"""Returns the number of raw data modules (bits) available at the given version number.
|
||||
These data modules are used for both user data codewords and error correction codewords.
|
||||
This stateless pure function could be implemented as a 40-entry lookup table."""
|
||||
if not 1 <= ver <= 40:
|
||||
raise ValueError("Version number out of range")
|
||||
result = (16 * ver + 128) * ver + 64
|
||||
if ver >= 2:
|
||||
numalign = ver // 7 + 2
|
||||
result -= (25 * numalign - 10) * numalign - 55
|
||||
if ver >= 7:
|
||||
result -= 18 * 2 # Subtract version information
|
||||
return result
|
||||
|
||||
|
||||
@staticmethod
|
||||
def _get_num_data_codewords(ver, ecl):
|
||||
"""Returns the number of 8-bit data (i.e. not error correction) codewords contained in any
|
||||
QR Code of the given version number and error correction level, with remainder bits discarded.
|
||||
This stateless pure function could be implemented as a (40*4)-cell lookup table."""
|
||||
return QrCode._get_num_raw_data_modules(ver) // 8 - QrCode._NUM_ERROR_CORRECTION_CODEWORDS[ecl.ordinal][ver]
|
||||
|
||||
|
||||
# ---- Tables of constants ----
|
||||
|
||||
# For use in getPenaltyScore(), when evaluating which mask is best.
|
||||
_PENALTY_N1 = 3
|
||||
_PENALTY_N2 = 3
|
||||
_PENALTY_N3 = 40
|
||||
_PENALTY_N4 = 10
|
||||
|
||||
_NUM_ERROR_CORRECTION_CODEWORDS = (
|
||||
# Version: (note that index 0 is for padding, and is set to an illegal value)
|
||||
# 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 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, 36, 37, 38, 39, 40 Error correction level
|
||||
(None, 7, 10, 15, 20, 26, 36, 40, 48, 60, 72, 80, 96, 104, 120, 132, 144, 168, 180, 196, 224, 224, 252, 270, 300, 312, 336, 360, 390, 420, 450, 480, 510, 540, 570, 570, 600, 630, 660, 720, 750), # Low
|
||||
(None, 10, 16, 26, 36, 48, 64, 72, 88, 110, 130, 150, 176, 198, 216, 240, 280, 308, 338, 364, 416, 442, 476, 504, 560, 588, 644, 700, 728, 784, 812, 868, 924, 980, 1036, 1064, 1120, 1204, 1260, 1316, 1372), # Medium
|
||||
(None, 13, 22, 36, 52, 72, 96, 108, 132, 160, 192, 224, 260, 288, 320, 360, 408, 448, 504, 546, 600, 644, 690, 750, 810, 870, 952, 1020, 1050, 1140, 1200, 1290, 1350, 1440, 1530, 1590, 1680, 1770, 1860, 1950, 2040), # Quartile
|
||||
(None, 17, 28, 44, 64, 88, 112, 130, 156, 192, 224, 264, 308, 352, 384, 432, 480, 532, 588, 650, 700, 750, 816, 900, 960, 1050, 1110, 1200, 1260, 1350, 1440, 1530, 1620, 1710, 1800, 1890, 1980, 2100, 2220, 2310, 2430)) # High
|
||||
|
||||
_NUM_ERROR_CORRECTION_BLOCKS = (
|
||||
# Version: (note that index 0 is for padding, and is set to an illegal value)
|
||||
# 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 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, 36, 37, 38, 39, 40 Error correction level
|
||||
(None, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 6, 7, 8, 8, 9, 9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25), # Low
|
||||
(None, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 5, 8, 9, 9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49), # Medium
|
||||
(None, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68), # Quartile
|
||||
(None, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81)) # High
|
||||
|
||||
_MASK_PATTERNS = (
|
||||
(lambda x, y: (x + y) % 2 ),
|
||||
(lambda x, y: y % 2 ),
|
||||
(lambda x, y: x % 3 ),
|
||||
(lambda x, y: (x + y) % 3 ),
|
||||
(lambda x, y: (x // 3 + y // 2) % 2 ),
|
||||
(lambda x, y: x * y % 2 + x * y % 3 ),
|
||||
(lambda x, y: (x * y % 2 + x * y % 3) % 2 ),
|
||||
(lambda x, y: ((x + y) % 2 + x * y % 3) % 2),
|
||||
)
|
||||
|
||||
|
||||
# ---- Public helper enumeration ----
|
||||
|
||||
class Ecc(object):
|
||||
"""Represents the error correction level used in a QR Code symbol."""
|
||||
# Private constructor
|
||||
def __init__(self, i, fb):
|
||||
self.ordinal = i # In the range 0 to 3 (unsigned 2-bit integer)
|
||||
self.formatbits = fb # In the range 0 to 3 (unsigned 2-bit integer)
|
||||
|
||||
# Create the class constants outside the class
|
||||
Ecc.LOW = Ecc(0, 1)
|
||||
Ecc.MEDIUM = Ecc(1, 0)
|
||||
Ecc.QUARTILE = Ecc(2, 3)
|
||||
Ecc.HIGH = Ecc(3, 2)
|
||||
|
||||
|
||||
|
||||
# ---- Data segment class ----
|
||||
|
||||
class QrSegment(object):
|
||||
"""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.
|
||||
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."""
|
||||
|
||||
# -- Public static factory functions --
|
||||
|
||||
@staticmethod
|
||||
def make_bytes(data):
|
||||
"""Returns a segment representing the given binary data encoded in byte mode."""
|
||||
bb = _BitBuffer()
|
||||
for b in data:
|
||||
if sys.version_info[0] < 3:
|
||||
b = ord(b)
|
||||
bb.append_bits(b, 8)
|
||||
return QrSegment(QrSegment.Mode.BYTE, len(data), bb.get_bits())
|
||||
|
||||
|
||||
@staticmethod
|
||||
def make_numeric(digits):
|
||||
"""Returns a segment representing the given string of decimal digits encoded in numeric mode."""
|
||||
if QrSegment.NUMERIC_REGEX.match(digits) is None:
|
||||
raise ValueError("String contains non-numeric characters")
|
||||
bb = _BitBuffer()
|
||||
for i in range(0, len(digits) - 2, 3): # Process groups of 3
|
||||
bb.append_bits(int(digits[i : i + 3]), 10)
|
||||
rem = len(digits) % 3
|
||||
if rem > 0: # 1 or 2 digits remaining
|
||||
bb.append_bits(int(digits[-rem : ]), rem * 3 + 1)
|
||||
return QrSegment(QrSegment.Mode.NUMERIC, len(digits), bb.get_bits())
|
||||
|
||||
|
||||
@staticmethod
|
||||
def make_alphanumeric(text):
|
||||
"""Returns a segment representing the given 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."""
|
||||
if QrSegment.ALPHANUMERIC_REGEX.match(text) is None:
|
||||
raise ValueError("String contains unencodable characters in alphanumeric mode")
|
||||
bb = _BitBuffer()
|
||||
for i in range(0, len(text) - 1, 2): # Process groups of 2
|
||||
temp = QrSegment.ALPHANUMERIC_ENCODING_TABLE[text[i]] * 45
|
||||
temp += QrSegment.ALPHANUMERIC_ENCODING_TABLE[text[i + 1]]
|
||||
bb.append_bits(temp, 11)
|
||||
if len(text) % 2 > 0: # 1 character remaining
|
||||
bb.append_bits(QrSegment.ALPHANUMERIC_ENCODING_TABLE[text[-1]], 6)
|
||||
return QrSegment(QrSegment.Mode.ALPHANUMERIC, len(text), bb.get_bits())
|
||||
|
||||
|
||||
# -- Constructor --
|
||||
|
||||
def __init__(self, mode, numch, bitdata):
|
||||
if numch < 0 or not isinstance(mode, QrSegment.Mode):
|
||||
raise ValueError()
|
||||
self._mode = mode
|
||||
self._numchars = numch
|
||||
self._bitdata = list(bitdata) # Defensive copy
|
||||
|
||||
|
||||
# -- Accessor methods --
|
||||
|
||||
def get_mode(self):
|
||||
return self._mode
|
||||
|
||||
def get_num_chars(self):
|
||||
return self._numchars
|
||||
|
||||
def get_bits(self):
|
||||
return list(self._bitdata) # Defensive copy
|
||||
|
||||
|
||||
# -- Constants --
|
||||
|
||||
# Can test whether a string is encodable in numeric mode (such as by using make_numeric())
|
||||
NUMERIC_REGEX = re.compile("[0-9]*$")
|
||||
|
||||
# Can test whether a string is encodable in alphanumeric mode (such as by using make_alphanumeric())
|
||||
ALPHANUMERIC_REGEX = re.compile("[A-Z0-9 $%*+./:-]*$")
|
||||
|
||||
# Dictionary of "0"->0, "A"->10, "$"->37, etc.
|
||||
ALPHANUMERIC_ENCODING_TABLE = {ch: i for (i, ch) in enumerate("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:")}
|
||||
|
||||
|
||||
# -- Helper enumeration --
|
||||
|
||||
class Mode(object):
|
||||
"""The mode field of a segment. Immutable. Provides methods to retrieve closely related values."""
|
||||
# Private constructor
|
||||
def __init__(self, modebits, charcounts):
|
||||
self._modebits = modebits
|
||||
self._charcounts = charcounts
|
||||
|
||||
def get_mode_bits(self):
|
||||
return self._modebits
|
||||
|
||||
def num_char_count_bits(self, ver):
|
||||
"""Returns the bit width of the segment character count field for this mode object at the given version number."""
|
||||
if 1 <= ver <= 9: return self._charcounts[0]
|
||||
elif 10 <= ver <= 26: return self._charcounts[1]
|
||||
elif 27 <= ver <= 40: return self._charcounts[2]
|
||||
else: raise ValueError("Version number out of range")
|
||||
|
||||
# Create the class constants outside the class
|
||||
Mode.NUMERIC = Mode(0x1, (10, 12, 14))
|
||||
Mode.ALPHANUMERIC = Mode(0x2, ( 9, 11, 13))
|
||||
Mode.BYTE = Mode(0x4, ( 8, 16, 16))
|
||||
Mode.KANJI = Mode(0x8, ( 8, 10, 12))
|
||||
|
||||
|
||||
|
||||
# ---- Private helper classes ----
|
||||
|
||||
class _ReedSolomonGenerator(object):
|
||||
"""Computes the Reed-Solomon error correction codewords for a sequence of data codewords
|
||||
at a given degree. Objects are immutable, and the state only depends on the degree.
|
||||
This class exists because the divisor polynomial does not need to be recalculated for every input."""
|
||||
|
||||
def __init__(self, degree):
|
||||
"""Creates a Reed-Solomon ECC generator for the given degree. This could be implemented
|
||||
as a lookup table over all possible parameter values, instead of as an algorithm."""
|
||||
if degree < 1 or degree > 255:
|
||||
raise ValueError("Degree out of range")
|
||||
|
||||
# Start with the monomial x^0
|
||||
self.coefficients = [0] * (degree - 1) + [1]
|
||||
|
||||
# Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
|
||||
# drop the highest term, and store the rest of the coefficients in order of descending powers.
|
||||
# Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
|
||||
root = 1
|
||||
for i in range(degree):
|
||||
# Multiply the current product by (x - r^i)
|
||||
for j in range(degree):
|
||||
self.coefficients[j] = _ReedSolomonGenerator.multiply(self.coefficients[j], root)
|
||||
if j + 1 < degree:
|
||||
self.coefficients[j] ^= self.coefficients[j + 1]
|
||||
root = (root << 1) ^ ((root >> 7) * 0x11D) # Multiply by 0x02 mod GF(2^8/0x11D)
|
||||
|
||||
|
||||
def get_remainder(self, data):
|
||||
"""Computes and returns the Reed-Solomon error correction codewords for the given sequence of data codewords.
|
||||
The returned object is always a new byte list. This method does not alter this object's state (because it is immutable)."""
|
||||
# Compute the remainder by performing polynomial division
|
||||
result = [0] * len(self.coefficients)
|
||||
for b in data:
|
||||
factor = (b ^ result[0])
|
||||
del result[0]
|
||||
result.append(0)
|
||||
for j in range(len(result)):
|
||||
result[j] ^= _ReedSolomonGenerator.multiply(self.coefficients[j], factor)
|
||||
return result
|
||||
|
||||
|
||||
@staticmethod
|
||||
def multiply(x, y):
|
||||
"""Returns the product of the two given field elements modulo GF(2^8/0x11D). The arguments and result
|
||||
are unsigned 8-bit integers. This could be implemented as a lookup table of 256*256 entries of uint8."""
|
||||
if x & 0xFF != x or y & 0xFF != y:
|
||||
raise ValueError("Byte out of range")
|
||||
# Russian peasant multiplication
|
||||
z = 0
|
||||
for i in reversed(range(8)):
|
||||
z = (z << 1) ^ ((z >> 7) * 0x11D)
|
||||
z ^= ((y >> i) & 1) * x
|
||||
assert z & 0xFF == z
|
||||
return z
|
||||
|
||||
|
||||
|
||||
class _BitBuffer(object):
|
||||
"""An appendable sequence of bits. Bits are packed in big endian within a byte."""
|
||||
|
||||
def __init__(self):
|
||||
"""Creates an empty bit buffer (length 0)."""
|
||||
self.data = []
|
||||
|
||||
def bit_length(self):
|
||||
"""Returns the number of bits in the buffer, which is a non-negative value."""
|
||||
return len(self.data)
|
||||
|
||||
def get_bits(self):
|
||||
"""Returns a copy of all bits."""
|
||||
return list(self.data)
|
||||
|
||||
def get_bytes(self):
|
||||
"""Returns a copy of all bytes, padding up to the nearest byte."""
|
||||
result = [0] * ((len(self.data) + 7) // 8)
|
||||
for (i, bit) in enumerate(self.data):
|
||||
result[i >> 3] |= bit << (7 - (i & 7))
|
||||
return result
|
||||
|
||||
def append_bits(self, val, n):
|
||||
"""Appends the given number of bits of the given value to this sequence. This requires 0 <= val < 2^n."""
|
||||
if n < 0 or not 0 <= val < (1 << n):
|
||||
raise ValueError("Value out of range")
|
||||
for i in reversed(range(n)): # Append bit by bit
|
||||
self.data.append((val >> i) & 1)
|
||||
|
||||
def append_all(self, seg):
|
||||
"""Appends the data of the given segment to this bit buffer."""
|
||||
if not isinstance(seg, QrSegment):
|
||||
raise TypeError("QrSegment expected")
|
||||
self.data.extend(seg.get_bits())
|
||||
Loading…
Reference in New Issue