Added Python port of the library, updated comments and tweaked code in Java and JavaScript versions.
Nayuki Minase
9 years ago
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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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@ -0,0 +1,813 @@
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#
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# QR Code generator library (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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import itertools, re, sys
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"""
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Public members inside this module "qrcodegen":
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- Function encode_text(str text, QrCode.Ecc ecl) -> QrCode
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- Function encode_text_to_segment(str text) -> QrSegment
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- Function encode_binary(bytes data, QrCode.Ecc ecl) -> QrCode
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- Function encode_segments(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(bytes bytes, int mask, int version, QrCode.Ecc ecl)
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- Method get_version() -> int
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- Method get_size() -> int
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- Method get_error_correction_level() -> QrCode.Ecc
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- Method get_mask() -> int
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- Method get_module(int x, int y) -> int
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- Method to_svg_str(int border) -> str
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- Enum Ecc:
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- Constants LOW, MEDIUM, QUARTILE, HIGH
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- Fields int ordinal, formatbits
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- Class QrSegment:
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- Function make_bytes(bytes data) -> QrSegment
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- Function make_numeric(str digits) -> QrSegment
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- Function make_alphanumeric(str text) -> QrSegment
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- Constructor QrSegment(QrSegment.Mode mode, int numch, list<int> bitdata)
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- Method get_mode() -> QrSegment.Mode
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- Method get_num_chars() -> int
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- Method get_bits() -> list<int>
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- Enum Mode:
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- Constants NUMERIC, ALPHANUMERIC, BYTE, KANJI
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- Method get_mode_bits() -> int
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- Method num_char_count_bits(int ver) -> int
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"""
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# ---- Public static factory functions for QrCode ----
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def encode_text(text, ecl):
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"""Returns a QR Code symbol representing the given Unicode text string at the given error correction level.
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As a conservative upper bound, this function is guaranteed to succeed for strings that have 738 or fewer Unicode
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code points (not UTF-16 code units). The smallest possible QR Code version is automatically chosen for the output."""
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seg = encode_text_to_segment(text)
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return encode_segments([seg], ecl)
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def encode_text_to_segment(text):
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"""Returns a QR Code segment representing the given Unicode text string."""
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if not isinstance(text, str) and (sys.version_info[0] >= 3 or not isinstance(text, unicode)):
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raise TypeError("Text string expected")
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# Select the most efficient segment encoding automatically
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if QrSegment.NUMERIC_REGEX.match(text) is not None:
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return QrSegment.make_numeric(text)
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elif QrSegment.ALPHANUMERIC_REGEX.match(text) is not None:
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return QrSegment.make_alphanumeric(text)
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else:
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return QrSegment.make_bytes(text.encode("UTF-8"))
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def encode_binary(data, ecl):
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"""Returns a QR Code symbol representing the given binary data string at the given 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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bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output."""
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if not isinstance(data, bytes):
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raise TypeError("Binary array expected")
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return QrCode.encode_segments([QrSegment.make_bytes(data)], ecl)
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def encode_segments(segs, ecl):
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"""Returns a QR Code symbol representing the given data segments at the given error
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correction level. The smallest possible QR Code version is automatically chosen for the output.
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This function allows the user to create a custom sequence of segments that switches
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between modes (such as alphanumeric and binary) to encode text more efficiently. This
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function is considered to be lower level than simply encoding text or binary data."""
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# Find the minimal version number to use
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for version in itertools.count(1): # Increment until the data fits in the QR Code
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if version > 40: # All versions could not fit the given data
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raise ValueError("Data too long")
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datacapacitybits = QrCode._get_num_data_codewords(version, ecl) * 8 # Number of data bits available
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# Calculate the total number of bits needed at this version number
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# to encode all the segments (i.e. segment metadata and payloads)
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datausedbits = 0
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for seg in segs:
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if seg.get_num_chars() < 0:
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raise AssertionError()
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ccbits = seg.get_mode().num_char_count_bits(version)
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if seg.get_num_chars() >= (1 << ccbits):
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# Segment length value doesn't fit in the length field's bit-width, so fail immediately
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break
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datausedbits += 4 + ccbits + len(seg.get_bits())
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else: # If the loop above did not break
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if datausedbits <= datacapacitybits:
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break # This version number is found to be suitable
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# Create the data bit string by concatenating all segments
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bb = _BitBuffer()
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for seg in segs:
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bb.append_bits(seg.get_mode().get_mode_bits(), 4)
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bb.append_bits(seg.get_num_chars(), seg.get_mode().num_char_count_bits(version))
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bb.append_all(seg)
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# Add terminator and pad up to a byte if applicable
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bb.append_bits(0, min(4, datacapacitybits - bb.bit_length()))
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bb.append_bits(0, -bb.bit_length() % 8)
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# Pad with alternate bytes until data capacity is reached
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for padbyte in itertools.cycle((0xEC, 0x11)):
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if bb.bit_length() >= datacapacitybits:
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break
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bb.append_bits(padbyte, 8)
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assert bb.bit_length() % 8 == 0
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# Create the QR Code symbol
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return QrCode(datacodewords=bb.get_bytes(), mask=-1, version=version, errcorlvl=ecl)
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# ---- QR Code symbol class ----
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class QrCode(object):
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"""Represents an immutable square grid of black or white cells for a QR Code symbol. This class covers the
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QR Code model 2 specification, supporting all versions (sizes) from 1 to 40, all 4 error correction levels."""
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# ---- Constructor ----
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def __init__(self, qrcode=None, datacodewords=None, mask=None, version=None, errcorlvl=None):
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"""This constructor can be called in one of two ways:
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- QrCode(datacodewords=list<int>, mask=int, version=int, errcorlvl=QrCode.Ecc):
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Creates a new QR Code symbol with the given version number, error correction level, binary data array,
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and mask number. This cumbersome constructor can be invoked directly by the user, but is considered
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to be even lower level than qrcodegen.encode_segments().
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- QrCode(qrcode=QrCode, mask=int):
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Creates a new QR Code symbol based on the given existing object, but with a potentially different
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mask pattern. The version, error correction level, codewords, etc. of the newly created object are
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all identical to the argument object; only the mask may differ.
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In both cases, mask = -1 is for automatic choice or 0 to 7 for fixed choice."""
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# Handle simple scalar fields
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if not -1 <= mask <= 7:
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raise ValueError("Mask value out of range")
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if datacodewords is not None and qrcode is None:
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if not 1 <= version <= 40:
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raise ValueError("Version value out of range")
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if not isinstance(errcorlvl, QrCode.Ecc):
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raise TypeError("QrCode.Ecc expected")
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elif qrcode is not None and datacodewords is None:
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version = qrcode._version
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errcorlvl = qrcode._errcorlvl
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else:
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raise ValueError("Exactly one of datacodewords or qrcode must be not None")
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self._version = version
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self._errcorlvl = errcorlvl
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self._size = version * 4 + 17
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if datacodewords is not None: # Render from scratch a QR Code based on data codewords
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if len(datacodewords) != QrCode._get_num_data_codewords(version, errcorlvl):
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raise ValueError("Invalid array length")
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# Initialize grids of modules
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self._modules = [[False] * self._size for _ in range(self._size)] # The modules of the QR symbol; start with entirely white grid
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self._isfunction = [[False] * self._size for _ in range(self._size)] # Indicates function modules that are not subjected to masking
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# Draw function patterns, draw all codewords
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self._draw_function_patterns()
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allcodewords = self._append_error_correction(datacodewords)
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self._draw_codewords(allcodewords)
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elif qrcode is not None: # Modify the mask of an existing QR Code
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self._modules = [list(row) for row in qrcode._modules] # Deep copy
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self._isfunction = qrcode._isfunction # Shallow copy because the data is read-only
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self._apply_mask(qrcode._mask) # Undo existing mask
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# Handle masking
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if mask == -1: # Automatically choose best mask
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minpenalty = 1 << 32
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for i in range(8):
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self._draw_format_bits(i)
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self._apply_mask(i)
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penalty = self._get_penalty_score()
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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