Fix for x86_64 build fail

[platform/upstream/connectedhomeip.git] / examples / common / QRCode / repo / rust / src / lib.rs

/* 
 * QR Code generator library (Rust)
 * 
 * Copyright (c) Project Nayuki. (MIT License)
 * https://www.nayuki.io/page/qr-code-generator-library
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 * - The above copyright notice and this permission notice shall be included in
 *   all copies or substantial portions of the Software.
 * - The Software is provided "as is", without warranty of any kind, express or
 *   implied, including but not limited to the warranties of merchantability,
 *   fitness for a particular purpose and noninfringement. In no event shall the
 *   authors or copyright holders be liable for any claim, damages or other
 *   liability, whether in an action of contract, tort or otherwise, arising from,
 *   out of or in connection with the Software or the use or other dealings in the
 *   Software.
 */


//! Generates QR Codes from text strings and byte arrays.
//! 
//! This project aims to be the best, clearest QR Code generator library.
//! The primary goals are flexible options and absolute correctness.
//! Secondary goals are compact implementation size and good documentation comments.
//! 
//! Home page with live JavaScript demo, extensive descriptions, and competitor comparisons:
//! [https://www.nayuki.io/page/qr-code-generator-library](https://www.nayuki.io/page/qr-code-generator-library)
//! 
//! # Features
//! 
//! Core features:
//! 
//! - Available in 6 programming languages, all with nearly equal functionality: Java, TypeScript/JavaScript, Python, Rust, C++, C
//! - Significantly shorter code but more documentation comments compared to competing libraries
//! - Supports encoding all 40 versions (sizes) and all 4 error correction levels, as per the QR Code Model 2 standard
//! - Output formats: Raw modules/pixels of the QR symbol, SVG XML string
//! - Detects finder-like penalty patterns more accurately than other implementations
//! - Encodes numeric and special-alphanumeric text in less space than general text
//! - Open source code under the permissive MIT License
//! 
//! Manual parameters:
//! 
//! - User can specify minimum and maximum version numbers allowed, then library will automatically choose smallest version in the range that fits the data
//! - User can specify mask pattern manually, otherwise library will automatically evaluate all 8 masks and select the optimal one
//! - User can specify absolute error correction level, or allow the library to boost it if it doesn't increase the version number
//! - User can create a list of data segments manually and add ECI segments
//! 
//! # Examples
//! 
//! ```
//! extern crate qrcodegen;
//! use qrcodegen::QrCode;
//! use qrcodegen::QrCodeEcc;
//! use qrcodegen::QrSegment;
//! ```
//! 
//! Simple operation:
//! 
//! ```
//! let qr = QrCode::encode_text("Hello, world!",
//!     QrCodeEcc::Medium).unwrap();
//! let svg = qr.to_svg_string(4);
//! ```
//! 
//! Manual operation:
//! 
//! ```
//! let chrs: Vec<char> = "3141592653589793238462643383".chars().collect();
//! let segs = QrSegment::make_segments(&chrs);
//! let qr = QrCode::encode_segments_advanced(
//!     &segs, QrCodeEcc::High, 5, 5, Some(Mask::new(2)), false).unwrap();
//! for y in 0 .. qr.size() {
//!     for x in 0 .. qr.size() {
//!         (... paint qr.get_module(x, y) ...)
//!     }
//! }
//! ```


/*---- QrCode functionality ----*/

/// A QR Code symbol, which is a type of two-dimension barcode.
/// 
/// Invented by Denso Wave and described in the ISO/IEC 18004 standard.
/// 
/// Instances of this struct represent an immutable square grid of black and white cells.
/// The impl provides static factory functions to create a QR Code from text or binary data.
/// The struct and impl cover the QR Code Model 2 specification, supporting all versions
/// (sizes) from 1 to 40, all 4 error correction levels, and 4 character encoding modes.
/// 
/// Ways to create a QR Code object:
/// 
/// - High level: Take the payload data and call `QrCode::encode_text()` or `QrCode::encode_binary()`.
/// - Mid level: Custom-make the list of segments and call
///   `QrCode::encode_segments()` or `QrCode::encode_segments_advanced()`.
/// - Low level: Custom-make the array of data codeword bytes (including segment
///   headers and final padding, excluding error correction codewords), supply the
///   appropriate version number, and call the `QrCode::encode_codewords()` constructor.
/// 
/// (Note that all ways require supplying the desired error correction level.)
#[derive(Clone, PartialEq, Eq)]
pub struct QrCode {
        
        // Scalar parameters:
        
        // The version number of this QR Code, which is between 1 and 40 (inclusive).
        // This determines the size of this barcode.
        version: Version,
        
        // The width and height of this QR Code, measured in modules, between
        // 21 and 177 (inclusive). This is equal to version * 4 + 17.
        size: i32,
        
        // The error correction level used in this QR Code.
        errorcorrectionlevel: QrCodeEcc,
        
        // The index of the mask pattern used in this QR Code, which is between 0 and 7 (inclusive).
        // Even if a QR Code is created with automatic masking requested (mask = None),
        // the resulting object still has a mask value between 0 and 7.
        mask: Mask,
        
        // Grids of modules/pixels, with dimensions of size*size:
        
        // The modules of this QR Code (false = white, true = black).
        // Immutable after constructor finishes. Accessed through get_module().
        modules: Vec<bool>,
        
        // Indicates function modules that are not subjected to masking. Discarded when constructor finishes.
        isfunction: Vec<bool>,
        
}


impl QrCode {
        
        /*---- Static factory functions (high level) ----*/
        
        /// Returns a QR Code 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-8 code units) if the low error correction level is used. The smallest possible
        /// QR Code version is automatically chosen for the output. The ECC level of the result may be higher than
        /// the ecl argument if it can be done without increasing the version.
        /// 
        /// Returns a wrapped `QrCode` if successful, or `Err` if the
        /// data is too long to fit in any version at the given ECC level.
        pub fn encode_text(text: &str, ecl: QrCodeEcc) -> Result<Self,DataTooLong> {
                let chrs: Vec<char> = text.chars().collect();
                let segs: Vec<QrSegment> = QrSegment::make_segments(&chrs);
                QrCode::encode_segments(&segs, ecl)
        }
        
        
        /// Returns a QR Code representing the given binary data 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.
        /// The ECC level of the result may be higher than the ecl argument if it can be done without increasing the version.
        /// 
        /// Returns a wrapped `QrCode` if successful, or `Err` if the
        /// data is too long to fit in any version at the given ECC level.
        pub fn encode_binary(data: &[u8], ecl: QrCodeEcc) -> Result<Self,DataTooLong> {
                let segs: [QrSegment; 1] = [QrSegment::make_bytes(data)];
                QrCode::encode_segments(&segs, ecl)
        }
        
        
        /*---- Static factory functions (mid level) ----*/
        
        /// Returns a QR Code representing the given segments at the given error correction level.
        /// 
        /// The smallest possible QR Code version is automatically chosen for the output. The ECC level
        /// of the result may be higher than the ecl argument if it can be done without increasing the version.
        /// 
        /// This function allows the user to create a custom sequence of segments that switches
        /// between modes (such as alphanumeric and byte) to encode text in less space.
        /// This is a mid-level API; the high-level API is `encode_text()` and `encode_binary()`.
        /// 
        /// Returns a wrapped `QrCode` if successful, or `Err` if the
        /// data is too long to fit in any version at the given ECC level.
        pub fn encode_segments(segs: &[QrSegment], ecl: QrCodeEcc) -> Result<Self,DataTooLong> {
                QrCode::encode_segments_advanced(segs, ecl, Version::MIN, Version::MAX, None, true)
        }
        
        
        /// Returns a QR Code representing the given segments with the given encoding parameters.
        /// 
        /// The smallest possible QR Code version within the given range is automatically
        /// chosen for the output. Iff boostecl is `true`, then the ECC level of the result
        /// may be higher than the ecl argument if it can be done without increasing the
        /// version. The mask number is either between 0 to 7 (inclusive) to force that
        /// mask, or `None` to automatically choose an appropriate mask (which may be slow).
        /// 
        /// This function allows the user to create a custom sequence of segments that switches
        /// between modes (such as alphanumeric and byte) to encode text in less space.
        /// This is a mid-level API; the high-level API is `encode_text()` and `encode_binary()`.
        /// 
        /// Returns a wrapped `QrCode` if successful, or `Err` if the data is too
        /// long to fit in any version in the given range at the given ECC level.
        pub fn encode_segments_advanced(segs: &[QrSegment], mut ecl: QrCodeEcc,
                        minversion: Version, maxversion: Version, mask: Option<Mask>, boostecl: bool) -> Result<Self,DataTooLong> {
                assert!(minversion.value() <= maxversion.value(), "Invalid value");
                
                // Find the minimal version number to use
                let mut version: Version = minversion;
                let datausedbits: usize = loop {
                        // Number of data bits available
                        let datacapacitybits: usize = QrCode::get_num_data_codewords(version, ecl) * 8;
                        let dataused: Option<usize> = QrSegment::get_total_bits(segs, version);
                        if dataused.map_or(false, |n| n <= datacapacitybits) {
                                break dataused.unwrap();  // This version number is found to be suitable
                        } else if version.value() >= maxversion.value() {  // All versions in the range could not fit the given data
                                let msg: String = match dataused {
                                        None => String::from("Segment too long"),
                                        Some(n) => format!("Data length = {} bits, Max capacity = {} bits",
                                                n, datacapacitybits),
                                };
                                return Err(DataTooLong(msg));
                        } else {
                                version = Version::new(version.value() + 1);
                        }
                };
                
                // Increase the error correction level while the data still fits in the current version number
                for &newecl in &[QrCodeEcc::Medium, QrCodeEcc::Quartile, QrCodeEcc::High] {  // From low to high
                        if boostecl && datausedbits <= QrCode::get_num_data_codewords(version, newecl) * 8 {
                                ecl = newecl;
                        }
                }
                
                // Concatenate all segments to create the data bit string
                let mut bb = BitBuffer(Vec::new());
                for seg in segs {
                        bb.append_bits(seg.mode.mode_bits(), 4);
                        bb.append_bits(seg.numchars as u32, seg.mode.num_char_count_bits(version));
                        bb.0.extend_from_slice(&seg.data);
                }
                assert_eq!(bb.0.len(), datausedbits);
                
                // Add terminator and pad up to a byte if applicable
                let datacapacitybits: usize = QrCode::get_num_data_codewords(version, ecl) * 8;
                assert!(bb.0.len() <= datacapacitybits);
                let numzerobits: usize = std::cmp::min(4, datacapacitybits - bb.0.len());
                bb.append_bits(0, numzerobits as u8);
                let numzerobits: usize = bb.0.len().wrapping_neg() & 7;
                bb.append_bits(0, numzerobits as u8);
                assert_eq!(bb.0.len() % 8, 0, "Assertion error");
                
                // Pad with alternating bytes until data capacity is reached
                for &padbyte in [0xEC, 0x11].iter().cycle() {
                        if bb.0.len() >= datacapacitybits {
                                break;
                        }
                        bb.append_bits(padbyte, 8);
                }
                
                // Pack bits into bytes in big endian
                let mut datacodewords = vec![0u8; bb.0.len() / 8];
                for (i, &bit) in bb.0.iter().enumerate() {
                        datacodewords[i >> 3] |= u8::from(bit) << (7 - (i & 7));
                }
                
                // Create the QR Code object
                Ok(QrCode::encode_codewords(version, ecl, &datacodewords, mask))
        }
        
        
        /*---- Constructor (low level) ----*/
        
        /// Creates a new QR Code with the given version number,
        /// error correction level, data codeword bytes, and mask number.
        /// 
        /// This is a low-level API that most users should not use directly.
        /// A mid-level API is the `encode_segments()` function.
        pub fn encode_codewords(ver: Version, ecl: QrCodeEcc, datacodewords: &[u8], mut mask: Option<Mask>) -> Self {
                // Initialize fields
                let size = usize::from(ver.value()) * 4 + 17;
                let mut result = Self {
                        version: ver,
                        size: size as i32,
                        mask: Mask::new(0),  // Dummy value
                        errorcorrectionlevel: ecl,
                        modules   : vec![false; size * size],  // Initially all white
                        isfunction: vec![false; size * size],
                };
                
                // Compute ECC, draw modules
                result.draw_function_patterns();
                let allcodewords: Vec<u8> = result.add_ecc_and_interleave(datacodewords);
                result.draw_codewords(&allcodewords);
                
                // Do masking
                if mask.is_none() {  // Automatically choose best mask
                        let mut minpenalty = std::i32::MAX;
                        for i in 0u8 .. 8 {
                                let newmask = Mask::new(i);
                                result.apply_mask(newmask);
                                result.draw_format_bits(newmask);
                                let penalty: i32 = result.get_penalty_score();
                                if penalty < minpenalty {
                                        mask = Some(newmask);
                                        minpenalty = penalty;
                                }
                                result.apply_mask(newmask);  // Undoes the mask due to XOR
                        }
                }
                let mask: Mask = mask.unwrap();
                result.mask = mask;
                result.apply_mask(mask);  // Apply the final choice of mask
                result.draw_format_bits(mask);  // Overwrite old format bits
                
                result.isfunction.clear();
                result.isfunction.shrink_to_fit();
                result
        }
        
        
        /*---- Public methods ----*/
        
        /// Returns this QR Code's version, in the range [1, 40].
        pub fn version(&self) -> Version {
                self.version
        }
        
        
        /// Returns this QR Code's size, in the range [21, 177].
        pub fn size(&self) -> i32 {
                self.size
        }
        
        
        /// Returns this QR Code's error correction level.
        pub fn error_correction_level(&self) -> QrCodeEcc {
                self.errorcorrectionlevel
        }
        
        
        /// Returns this QR Code's mask, in the range [0, 7].
        pub fn mask(&self) -> Mask {
                self.mask
        }
        
        
        /// Returns the color of the module (pixel) at the given coordinates,
        /// which is `false` for white or `true` for black.
        /// 
        /// The top left corner has the coordinates (x=0, y=0). If the given
        /// coordinates are out of bounds, then `false` (white) is returned.
        pub fn get_module(&self, x: i32, y: i32) -> bool {
                0 <= x && x < self.size && 0 <= y && y < self.size && self.module(x, y)
        }
        
        
        // Returns the color of the module at the given coordinates, which must be in bounds.
        fn module(&self, x: i32, y: i32) -> bool {
                self.modules[(y * self.size + x) as usize]
        }
        
        
        // Returns a mutable reference to the module's color at the given coordinates, which must be in bounds.
        fn module_mut(&mut self, x: i32, y: i32) -> &mut bool {
                &mut self.modules[(y * self.size + x) as usize]
        }
        
        
        /// Returns a string of SVG code for an image depicting
        /// this QR Code, with the given number of border modules.
        /// 
        /// The string always uses Unix newlines (\n), regardless of the platform.
        pub fn to_svg_string(&self, border: i32) -> String {
                assert!(border >= 0, "Border must be non-negative");
                let mut result = String::new();
                result += "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
                result += "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n";
                let dimension = self.size.checked_add(border.checked_mul(2).unwrap()).unwrap();
                result += &format!(
                        "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 {0} {0}\" stroke=\"none\">\n", dimension);
                result += "\t<rect width=\"100%\" height=\"100%\" fill=\"#FFFFFF\"/>\n";
                result += "\t<path d=\"";
                for y in 0 .. self.size {
                        for x in 0 .. self.size {
                                if self.get_module(x, y) {
                                        if x != 0 || y != 0 {
                                                result += " ";
                                        }
                                        result += &format!("M{},{}h1v1h-1z", x + border, y + border);
                                }
                        }
                }
                result += "\" fill=\"#000000\"/>\n";
                result += "</svg>\n";
                result
        }
        
        
        /*---- Private helper methods for constructor: Drawing function modules ----*/
        
        // Reads this object's version field, and draws and marks all function modules.
        fn draw_function_patterns(&mut self) {
                // Draw horizontal and vertical timing patterns
                let size: i32 = self.size;
                for i in 0 .. 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(size - 4, 3);
                self.draw_finder_pattern(3, size - 4);
                
                // Draw numerous alignment patterns
                let alignpatpos: Vec<i32> = self.get_alignment_pattern_positions();
                let numalign: usize = alignpatpos.len();
                for i in 0 .. numalign {
                        for j in 0 .. numalign {
                                // Don't draw on the three finder corners
                                if !(i == 0 && j == 0 || i == 0 && j == numalign - 1 || i == numalign - 1 && j == 0) {
                                        self.draw_alignment_pattern(alignpatpos[i], alignpatpos[j]);
                                }
                        }
                }
                
                // Draw configuration data
                self.draw_format_bits(Mask::new(0));  // Dummy mask value; overwritten later in the constructor
                self.draw_version();
        }
        
        
        // 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.
        fn draw_format_bits(&mut self, mask: Mask) {
                // Calculate error correction code and pack bits
                let bits: u32 = {
                        // errcorrlvl is uint2, mask is uint3
                        let data: u32 = u32::from(self.errorcorrectionlevel.format_bits() << 3 | mask.value());
                        let mut rem: u32 = data;
                        for _ in 0 .. 10 {
                                rem = (rem << 1) ^ ((rem >> 9) * 0x537);
                        }
                        (data << 10 | rem) ^ 0x5412  // uint15
                };
                assert_eq!(bits >> 15, 0, "Assertion error");
                
                // Draw first copy
                for i in 0 .. 6 {
                        self.set_function_module(8, i, get_bit(bits, i));
                }
                self.set_function_module(8, 7, get_bit(bits, 6));
                self.set_function_module(8, 8, get_bit(bits, 7));
                self.set_function_module(7, 8, get_bit(bits, 8));
                for i in 9 .. 15 {
                        self.set_function_module(14 - i, 8, get_bit(bits, i));
                }
                
                // Draw second copy
                let size: i32 = self.size;
                for i in 0 .. 8 {
                        self.set_function_module(size - 1 - i, 8, get_bit(bits, i));
                }
                for i in 8 .. 15 {
                        self.set_function_module(8, size - 15 + i, get_bit(bits, i));
                }
                self.set_function_module(8, size - 8, true);  // Always black
        }
        
        
        // Draws two copies of the version bits (with its own error correction code),
        // based on this object's version field, iff 7 <= version <= 40.
        fn draw_version(&mut self) {
                if self.version.value() < 7 {
                        return;
                }
                
                // Calculate error correction code and pack bits
                let bits: u32 = {
                        let data = u32::from(self.version.value());  // uint6, in the range [7, 40]
                        let mut rem: u32 = data;
                        for _ in 0 .. 12 {
                                rem = (rem << 1) ^ ((rem >> 11) * 0x1F25);
                        }
                        data << 12 | rem  // uint18
                };
                assert!(bits >> 18 == 0, "Assertion error");
                
                // Draw two copies
                for i in 0 .. 18 {
                        let bit: bool = get_bit(bits, i);
                        let a: i32 = self.size - 11 + i % 3;
                        let b: i32 = i / 3;
                        self.set_function_module(a, b, bit);
                        self.set_function_module(b, a, bit);
                }
        }
        
        
        // Draws a 9*9 finder pattern including the border separator,
        // with the center module at (x, y). Modules can be out of bounds.
        fn draw_finder_pattern(&mut self, x: i32, y: i32) {
                for dy in -4 ..= 4 {
                        for dx in -4 ..= 4 {
                                let xx: i32 = x + dx;
                                let yy: i32 = y + dy;
                                if 0 <= xx && xx < self.size && 0 <= yy && yy < self.size {
                                        let dist: i32 = std::cmp::max(dx.abs(), dy.abs());  // Chebyshev/infinity norm
                                        self.set_function_module(xx, yy, dist != 2 && dist != 4);
                                }
                        }
                }
        }
        
        
        // Draws a 5*5 alignment pattern, with the center module
        // at (x, y). All modules must be in bounds.
        fn draw_alignment_pattern(&mut self, x: i32, y: i32) {
                for dy in -2 ..= 2 {
                        for dx in -2 ..= 2 {
                                self.set_function_module(x + dx, y + dy, std::cmp::max(dx.abs(), dy.abs()) != 1);
                        }
                }
        }
        
        
        // Sets the color of a module and marks it as a function module.
        // Only used by the constructor. Coordinates must be in bounds.
        fn set_function_module(&mut self, x: i32, y: i32, isblack: bool) {
                *self.module_mut(x, y) = isblack;
                self.isfunction[(y * self.size + x) as usize] = true;
        }
        
        
        /*---- Private helper methods for constructor: Codewords and masking ----*/
        
        // 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.
        fn add_ecc_and_interleave(&self, data: &[u8]) -> Vec<u8> {
                let ver: Version = self.version;
                let ecl: QrCodeEcc = self.errorcorrectionlevel;
                assert_eq!(data.len(), QrCode::get_num_data_codewords(ver, ecl), "Illegal argument");
                
                // Calculate parameter numbers
                let numblocks: usize = QrCode::table_get(&NUM_ERROR_CORRECTION_BLOCKS, ver, ecl);
                let blockecclen: usize = QrCode::table_get(&ECC_CODEWORDS_PER_BLOCK  , ver, ecl);
                let rawcodewords: usize = QrCode::get_num_raw_data_modules(ver) / 8;
                let numshortblocks: usize = numblocks - rawcodewords % numblocks;
                let shortblocklen: usize = rawcodewords / numblocks;
                
                // Split data into blocks and append ECC to each block
                let mut blocks = Vec::<Vec<u8>>::with_capacity(numblocks);
                let rsdiv: Vec<u8> = QrCode::reed_solomon_compute_divisor(blockecclen);
                let mut k: usize = 0;
                for i in 0 .. numblocks {
                        let datlen: usize = shortblocklen - blockecclen + usize::from(i >= numshortblocks);
                        let mut dat = data[k .. k + datlen].to_vec();
                        k += datlen;
                        let ecc: Vec<u8> = QrCode::reed_solomon_compute_remainder(&dat, &rsdiv);
                        if i < numshortblocks {
                                dat.push(0);
                        }
                        dat.extend_from_slice(&ecc);
                        blocks.push(dat);
                }
                
                // Interleave (not concatenate) the bytes from every block into a single sequence
                let mut result = Vec::<u8>::with_capacity(rawcodewords);
                for i in 0 ..= shortblocklen {
                        for (j, block) in blocks.iter().enumerate() {
                                // Skip the padding byte in short blocks
                                if i != shortblocklen - blockecclen || j >= numshortblocks {
                                        result.push(block[i]);
                                }
                        }
                }
                result
        }
        
        
        // Draws the given sequence of 8-bit codewords (data and error correction) onto the entire
        // data area of this QR Code. Function modules need to be marked off before this is called.
        fn draw_codewords(&mut self, data: &[u8]) {
                assert_eq!(data.len(), QrCode::get_num_raw_data_modules(self.version) / 8, "Illegal argument");
                
                let mut i: usize = 0;  // Bit index into the data
                // Do the funny zigzag scan
                let mut right: i32 = self.size - 1;
                while right >= 1 {  // Index of right column in each column pair
                        if right == 6 {
                                right = 5;
                        }
                        for vert in 0 .. self.size {  // Vertical counter
                                for j in 0 .. 2 {
                                        let x: i32 = right - j;  // Actual x coordinate
                                        let upward: bool = (right + 1) & 2 == 0;
                                        let y: i32 = if upward { self.size - 1 - vert } else { vert };  // Actual y coordinate
                                        if !self.isfunction[(y * self.size + x) as usize] && i < data.len() * 8 {
                                                *self.module_mut(x, y) = get_bit(u32::from(data[i >> 3]), 7 - ((i & 7) as i32));
                                                i += 1;
                                        }
                                        // If this QR Code has any remainder bits (0 to 7), they were assigned as
                                        // 0/false/white by the constructor and are left unchanged by this method
                                }
                        }
                        right -= 2;
                }
                assert_eq!(i, data.len() * 8, "Assertion error");
        }
        
        
        // XORs the codeword modules in this QR Code with the given mask pattern.
        // The function modules must be marked and the codeword bits must be drawn
        // before masking. Due to the arithmetic of XOR, calling apply_mask() with
        // the same mask value a second time will undo the mask. A final well-formed
        // QR Code needs exactly one (not zero, two, etc.) mask applied.
        fn apply_mask(&mut self, mask: Mask) {
                for y in 0 .. self.size {
                        for x in 0 .. self.size {
                                let invert: bool = match mask.value() {
                                        0 => (x + y) % 2 == 0,
                                        1 => y % 2 == 0,
                                        2 => x % 3 == 0,
                                        3 => (x + y) % 3 == 0,
                                        4 => (x / 3 + y / 2) % 2 == 0,
                                        5 => x * y % 2 + x * y % 3 == 0,
                                        6 => (x * y % 2 + x * y % 3) % 2 == 0,
                                        7 => ((x + y) % 2 + x * y % 3) % 2 == 0,
                                        _ => unreachable!(),
                                };
                                *self.module_mut(x, y) ^= invert & !self.isfunction[(y * self.size + x) as usize];
                        }
                }
        }
        
        
        // 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.
        fn get_penalty_score(&self) -> i32 {
                let mut result: i32 = 0;
                let size: i32 = self.size;
                
                // Adjacent modules in row having same color, and finder-like patterns
                for y in 0 .. size {
                        let mut runcolor = false;
                        let mut runx: i32 = 0;
                        let mut runhistory = FinderPenalty::new(size);
                        for x in 0 .. size {
                                if self.module(x, y) == runcolor {
                                        runx += 1;
                                        if runx == 5 {
                                                result += PENALTY_N1;
                                        } else if runx > 5 {
                                                result += 1;
                                        }
                                } else {
                                        runhistory.add_history(runx);
                                        if !runcolor {
                                                result += runhistory.count_patterns() * PENALTY_N3;
                                        }
                                        runcolor = self.module(x, y);
                                        runx = 1;
                                }
                        }
                        result += runhistory.terminate_and_count(runcolor, runx) * PENALTY_N3;
                }
                // Adjacent modules in column having same color, and finder-like patterns
                for x in 0 .. size {
                        let mut runcolor = false;
                        let mut runy: i32 = 0;
                        let mut runhistory = FinderPenalty::new(size);
                        for y in 0 .. size {
                                if self.module(x, y) == runcolor {
                                        runy += 1;
                                        if runy == 5 {
                                                result += PENALTY_N1;
                                        } else if runy > 5 {
                                                result += 1;
                                        }
                                } else {
                                        runhistory.add_history(runy);
                                        if !runcolor {
                                                result += runhistory.count_patterns() * PENALTY_N3;
                                        }
                                        runcolor = self.module(x, y);
                                        runy = 1;
                                }
                        }
                        result += runhistory.terminate_and_count(runcolor, runy) * PENALTY_N3;
                }
                
                // 2*2 blocks of modules having same color
                for y in 0 .. size - 1 {
                        for x in 0 .. size - 1 {
                                let color: bool = self.module(x, y);
                                if color == self.module(x + 1, y) &&
                                   color == self.module(x, y + 1) &&
                                   color == self.module(x + 1, y + 1) {
                                        result += PENALTY_N2;
                                }
                        }
                }
                
                // Balance of black and white modules
                let black: i32 = self.modules.iter().copied().map(i32::from).sum();
                let total: i32 = size * size;  // Note that size is odd, so black/total != 1/2
                // Compute the smallest integer k >= 0 such that (45-5k)% <= black/total <= (55+5k)%
                let k: i32 = ((black * 20 - total * 10).abs() + total - 1) / total - 1;
                result += k * PENALTY_N4;
                result
        }
        
        
        /*---- Private helper functions ----*/
        
        // Returns an ascending list of positions of alignment patterns for this version number.
        // Each position is in the range [0,177), and are used on both the x and y axes.
        // This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
        fn get_alignment_pattern_positions(&self) -> Vec<i32> {
                let ver: u8 = self.version.value();
                if ver == 1 {
                        vec![]
                } else {
                        let numalign = i32::from(ver) / 7 + 2;
                        let step: i32 = if ver == 32 { 26 } else
                                {(i32::from(ver)*4 + numalign*2 + 1) / (numalign*2 - 2) * 2};
                        let mut result: Vec<i32> = (0 .. numalign - 1).map(
                                |i| self.size - 7 - i * step).collect();
                        result.push(6);
                        result.reverse();
                        result
                }
        }
        
        
        // Returns the number of data bits that can be stored in a QR Code of the given version number, after
        // all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
        // The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.
        fn get_num_raw_data_modules(ver: Version) -> usize {
                let ver = usize::from(ver.value());
                let mut result: usize = (16 * ver + 128) * ver + 64;
                if ver >= 2 {
                        let numalign: usize = ver / 7 + 2;
                        result -= (25 * numalign - 10) * numalign - 55;
                        if ver >= 7 {
                                result -= 36;
                        }
                }
                assert!(208 <= result && result <= 29648);
                result
        }
        
        
        // 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.
        fn get_num_data_codewords(ver: Version, ecl: QrCodeEcc) -> usize {
                QrCode::get_num_raw_data_modules(ver) / 8
                        - QrCode::table_get(&ECC_CODEWORDS_PER_BLOCK    , ver, ecl)
                        * QrCode::table_get(&NUM_ERROR_CORRECTION_BLOCKS, ver, ecl)
        }
        
        
        // Returns an entry from the given table based on the given values.
        fn table_get(table: &'static [[i8; 41]; 4], ver: Version, ecl: QrCodeEcc) -> usize {
                table[ecl.ordinal()][usize::from(ver.value())] as usize
        }
        
        
        // Returns a Reed-Solomon ECC generator polynomial for the given degree. This could be
        // implemented as a lookup table over all possible parameter values, instead of as an algorithm.
        fn reed_solomon_compute_divisor(degree: usize) -> Vec<u8> {
                assert!(1 <= degree && degree <= 255, "Degree out of range");
                // Polynomial coefficients are stored from highest to lowest power, excluding the leading term which is always 1.
                // For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array [255, 8, 93].
                let mut result = vec![0u8; degree - 1];
                result.push(1);  // Start off with the monomial x^0
                
                // Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
                // and drop the highest monomial term which is always 1x^degree.
                // Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
                let mut root: u8 = 1;
                for _ in 0 .. degree {  // Unused variable i
                        // Multiply the current product by (x - r^i)
                        for j in 0 .. degree {
                                result[j] = QrCode::reed_solomon_multiply(result[j], root);
                                if j + 1 < result.len() {
                                        result[j] ^= result[j + 1];
                                }
                        }
                        root = QrCode::reed_solomon_multiply(root, 0x02);
                }
                result
        }
        
        
        // Returns the Reed-Solomon error correction codeword for the given data and divisor polynomials.
        fn reed_solomon_compute_remainder(data: &[u8], divisor: &[u8]) -> Vec<u8> {
                let mut result = vec![0u8; divisor.len()];
                for b in data {  // Polynomial division
                        let factor: u8 = b ^ result.remove(0);
                        result.push(0);
                        for (x, &y) in result.iter_mut().zip(divisor.iter()) {
                                *x ^= QrCode::reed_solomon_multiply(y, factor);
                        }
                }
                result
        }
        
        
        // Returns the product of the two given field elements modulo GF(2^8/0x11D).
        // All inputs are valid. This could be implemented as a 256*256 lookup table.
        fn reed_solomon_multiply(x: u8, y: u8) -> u8 {
                // Russian peasant multiplication
                let mut z: u8 = 0;
                for i in (0 .. 8).rev() {
                        z = (z << 1) ^ ((z >> 7) * 0x1D);
                        z ^= ((y >> i) & 1) * x;
                }
                z
        }
        
}


/*---- Helper struct for get_penalty_score() ----*/

struct FinderPenalty {
        qr_size: i32,
        run_history: [i32; 7],
}


impl FinderPenalty {
        
        pub fn new(size: i32) -> Self {
                Self {
                        qr_size: size,
                        run_history: [0i32; 7],
                }
        }
        
        
        // Pushes the given value to the front and drops the last value.
        pub fn add_history(&mut self, mut currentrunlength: i32) {
                if self.run_history[0] == 0 {
                        currentrunlength += self.qr_size;  // Add white border to initial run
                }
                let rh = &mut self.run_history;
                for i in (0 .. rh.len()-1).rev() {
                        rh[i + 1] = rh[i];
                }
                rh[0] = currentrunlength;
        }
        
        
        // Can only be called immediately after a white run is added, and returns either 0, 1, or 2.
        pub fn count_patterns(&self) -> i32 {
                let rh = &self.run_history;
                let n = rh[1];
                assert!(n <= self.qr_size * 3);
                let core = n > 0 && rh[2] == n && rh[3] == n * 3 && rh[4] == n && rh[5] == n;
                ( i32::from(core && rh[0] >= n * 4 && rh[6] >= n)
                + i32::from(core && rh[6] >= n * 4 && rh[0] >= n))
        }
        
        
        // Must be called at the end of a line (row or column) of modules.
        pub fn terminate_and_count(mut self, currentruncolor: bool, mut currentrunlength: i32) -> i32 {
                if currentruncolor {  // Terminate black run
                        self.add_history(currentrunlength);
                        currentrunlength = 0;
                }
                currentrunlength += self.qr_size;  // Add white border to final run
                self.add_history(currentrunlength);
                self.count_patterns()
        }
        
}


/*---- Constants and tables ----*/

// For use in get_penalty_score(), when evaluating which mask is best.
const PENALTY_N1: i32 =  3;
const PENALTY_N2: i32 =  3;
const PENALTY_N3: i32 = 40;
const PENALTY_N4: i32 = 10;


static ECC_CODEWORDS_PER_BLOCK: [[i8; 41]; 4] = [
        // 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
        [-1,  7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30],  // Low
        [-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28],  // Medium
        [-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30],  // Quartile
        [-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30],  // High
];

static NUM_ERROR_CORRECTION_BLOCKS: [[i8; 41]; 4] = [
        // 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
        [-1, 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
        [-1, 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
        [-1, 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
        [-1, 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
];



/*---- QrCodeEcc functionality ----*/

/// The error correction level in a QR Code symbol.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug)]
pub enum QrCodeEcc {
        /// The QR Code can tolerate about  7% erroneous codewords.
        Low     ,
        /// The QR Code can tolerate about 15% erroneous codewords.
        Medium  ,
        /// The QR Code can tolerate about 25% erroneous codewords.
        Quartile,
        /// The QR Code can tolerate about 30% erroneous codewords.
        High    ,
}


impl QrCodeEcc {
        
        // Returns an unsigned 2-bit integer (in the range 0 to 3).
        fn ordinal(self) -> usize {
                use QrCodeEcc::*;
                match self {
                        Low      => 0,
                        Medium   => 1,
                        Quartile => 2,
                        High     => 3,
                }
        }
        
        
        // Returns an unsigned 2-bit integer (in the range 0 to 3).
        fn format_bits(self) -> u8 {
                use QrCodeEcc::*;
                match self {
                        Low      => 1,
                        Medium   => 0,
                        Quartile => 3,
                        High     => 2,
                }
        }
        
}



/*---- QrSegment functionality ----*/

/// A segment of character/binary/control data in a QR Code symbol.
/// 
/// Instances of this struct are immutable.
/// 
/// The mid-level way to create a segment is to take the payload data
/// and call a static factory function such as `QrSegment::make_numeric()`.
/// The low-level way to create a segment is to custom-make the bit buffer
/// and call the `QrSegment::new()` constructor with appropriate values.
/// 
/// This segment struct 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.
#[derive(Clone, PartialEq, Eq)]
pub struct QrSegment {
        
        // The mode indicator of this segment. Accessed through mode().
        mode: QrSegmentMode,
        
        // The length of this segment's unencoded data. Measured in characters for
        // numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.
        // Not the same as the data's bit length. Accessed through num_chars().
        numchars: usize,
        
        // The data bits of this segment. Accessed through data().
        data: Vec<bool>,
        
}


impl QrSegment {
        
        /*---- Static factory functions (mid level) ----*/
        
        /// Returns a segment representing the given binary data encoded in byte mode.
        /// 
        /// All input byte slices are acceptable.
        /// 
        /// Any text string can be converted to UTF-8 bytes and encoded as a byte mode segment.
        pub fn make_bytes(data: &[u8]) -> Self {
                let mut bb = BitBuffer(Vec::with_capacity(data.len() * 8));
                for &b in data {
                        bb.append_bits(u32::from(b), 8);
                }
                QrSegment::new(QrSegmentMode::Byte, data.len(), bb.0)
        }
        
        
        /// Returns a segment representing the given string of decimal digits encoded in numeric mode.
        /// 
        /// Panics if the string contains non-digit characters.
        pub fn make_numeric(text: &[char]) -> Self {
                let mut bb = BitBuffer(Vec::with_capacity(text.len() * 3 + (text.len() + 2) / 3));
                let mut accumdata: u32 = 0;
                let mut accumcount: u8 = 0;
                for &c in text {
                        assert!('0' <= c && c <= '9', "String contains non-numeric characters");
                        accumdata = accumdata * 10 + (u32::from(c) - u32::from('0'));
                        accumcount += 1;
                        if accumcount == 3 {
                                bb.append_bits(accumdata, 10);
                                accumdata = 0;
                                accumcount = 0;
                        }
                }
                if accumcount > 0 {  // 1 or 2 digits remaining
                        bb.append_bits(accumdata, accumcount * 3 + 1);
                }
                QrSegment::new(QrSegmentMode::Numeric, text.len(), bb.0)
        }
        
        
        /// 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.
        /// 
        /// Panics if the string contains non-encodable characters.
        pub fn make_alphanumeric(text: &[char]) -> Self {
                let mut bb = BitBuffer(Vec::with_capacity(text.len() * 5 + (text.len() + 1) / 2));
                let mut accumdata: u32 = 0;
                let mut accumcount: u32 = 0;
                for &c in text {
                        let i: usize = ALPHANUMERIC_CHARSET.iter().position(|&x| x == c)
                                .expect("String contains unencodable characters in alphanumeric mode");
                        accumdata = accumdata * 45 + (i as u32);
                        accumcount += 1;
                        if accumcount == 2 {
                                bb.append_bits(accumdata, 11);
                                accumdata = 0;
                                accumcount = 0;
                        }
                }
                if accumcount > 0 {  // 1 character remaining
                        bb.append_bits(accumdata, 6);
                }
                QrSegment::new(QrSegmentMode::Alphanumeric, text.len(), bb.0)
        }
        
        
        /// Returns a list of zero or more segments to represent the given Unicode text string.
        /// 
        /// The result may use various segment modes and switch
        /// modes to optimize the length of the bit stream.
        pub fn make_segments(text: &[char]) -> Vec<Self> {
                if text.is_empty() {
                        vec![]
                } else if QrSegment::is_numeric(text) {
                        vec![QrSegment::make_numeric(text)]
                } else if QrSegment::is_alphanumeric(text) {
                        vec![QrSegment::make_alphanumeric(text)]
                } else {
                        let s: String = text.iter().cloned().collect();
                        vec![QrSegment::make_bytes(s.as_bytes())]
                }
        }
        
        
        /// Returns a segment representing an Extended Channel Interpretation
        /// (ECI) designator with the given assignment value.
        pub fn make_eci(assignval: u32) -> Self {
                let mut bb = BitBuffer(Vec::with_capacity(24));
                if assignval < (1 << 7) {
                        bb.append_bits(assignval, 8);
                } else if assignval < (1 << 14) {
                        bb.append_bits(2, 2);
                        bb.append_bits(assignval, 14);
                } else if assignval < 1_000_000 {
                        bb.append_bits(6, 3);
                        bb.append_bits(assignval, 21);
                } else {
                        panic!("ECI assignment value out of range");
                }
                QrSegment::new(QrSegmentMode::Eci, 0, bb.0)
        }
        
        
        /*---- Constructor (low level) ----*/
        
        /// Creates a new QR Code segment with the given attributes and data.
        /// 
        /// The character count (numchars) must agree with the mode and
        /// the bit buffer length, but the constraint isn't checked.
        pub fn new(mode: QrSegmentMode, numchars: usize, data: Vec<bool>) -> Self {
                Self { mode, numchars, data }
        }
        
        
        /*---- Instance field getters ----*/
        
        /// Returns the mode indicator of this segment.
        pub fn mode(&self) -> QrSegmentMode {
                self.mode
        }
        
        
        /// Returns the character count field of this segment.
        pub fn num_chars(&self) -> usize {
                self.numchars
        }
        
        
        /// Returns the data bits of this segment.
        pub fn data(&self) -> &Vec<bool> {
                &self.data
        }
        
        
        /*---- Other static functions ----*/
        
        // Calculates and returns the number of bits needed to encode the given
        // segments at the given version. The result is None if a segment has too many
        // characters to fit its length field, or the total bits exceeds usize::MAX.
        fn get_total_bits(segs: &[Self], version: Version) -> Option<usize> {
                let mut result: usize = 0;
                for seg in segs {
                        let ccbits: u8 = seg.mode.num_char_count_bits(version);
                        // ccbits can be as large as 16, but usize can be as small as 16
                        if let Some(limit) = 1usize.checked_shl(u32::from(ccbits)) {
                                if seg.numchars >= limit {
                                        return None;  // The segment's length doesn't fit the field's bit width
                                }
                        }
                        result = result.checked_add(4 + usize::from(ccbits))?;
                        result = result.checked_add(seg.data.len())?;
                }
                Some(result)
        }
        
        
        // Tests whether the given string can be encoded as a segment in alphanumeric mode.
        // A string is encodable iff each character is in the following set: 0 to 9, A to Z
        // (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
        fn is_alphanumeric(text: &[char]) -> bool {
                text.iter().all(|c| ALPHANUMERIC_CHARSET.contains(c))
        }
        
        
        // Tests whether the given string can be encoded as a segment in numeric mode.
        // A string is encodable iff each character is in the range 0 to 9.
        fn is_numeric(text: &[char]) -> bool {
                text.iter().all(|&c| '0' <= c && c <= '9')
        }
        
}


// The set of all legal characters in alphanumeric mode,
// where each character value maps to the index in the string.
static ALPHANUMERIC_CHARSET: [char; 45] = ['0','1','2','3','4','5','6','7','8','9',
        'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
        ' ','$','%','*','+','-','.','/',':'];



/*---- QrSegmentMode functionality ----*/

/// Describes how a segment's data bits are interpreted.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum QrSegmentMode {
        Numeric,
        Alphanumeric,
        Byte,
        Kanji,
        Eci,
}


impl QrSegmentMode {
        
        // Returns an unsigned 4-bit integer value (range 0 to 15)
        // representing the mode indicator bits for this mode object.
        fn mode_bits(self) -> u32 {
                use QrSegmentMode::*;
                match self {
                        Numeric      => 0x1,
                        Alphanumeric => 0x2,
                        Byte         => 0x4,
                        Kanji        => 0x8,
                        Eci          => 0x7,
                }
        }
        
        
        // Returns the bit width of the character count field for a segment in this mode
        // in a QR Code at the given version number. The result is in the range [0, 16].
        fn num_char_count_bits(self, ver: Version) -> u8 {
                use QrSegmentMode::*;
                (match self {
                        Numeric      => [10, 12, 14],
                        Alphanumeric => [ 9, 11, 13],
                        Byte         => [ 8, 16, 16],
                        Kanji        => [ 8, 10, 12],
                        Eci          => [ 0,  0,  0],
                })[usize::from((ver.value() + 7) / 17)]
        }
        
}



/*---- Bit buffer functionality ----*/

/// An appendable sequence of bits (0s and 1s).
/// 
/// Mainly used by QrSegment.
pub struct BitBuffer(pub Vec<bool>);


impl BitBuffer {
        /// Appends the given number of low-order bits of the given value to this buffer.
        /// 
        /// Requires len &#x2264; 31 and val &lt; 2<sup>len</sup>.
        pub fn append_bits(&mut self, val: u32, len: u8) {
                assert!(len <= 31 && (val >> len) == 0, "Value out of range");
                self.0.extend((0 .. i32::from(len)).rev().map(|i| get_bit(val, i)));  // Append bit by bit
        }
}



/*---- Miscellaneous values ----*/

/// The error type when the supplied data does not fit any QR Code version.
///
/// Ways to handle this exception include:
/// 
/// - Decrease the error correction level if it was greater than `QrCodeEcc::Low`.
/// - If the `encode_segments_advanced()` function was called, then increase the maxversion
///   argument if it was less than `Version::MAX`. (This advice does not apply to the
///   other factory functions because they search all versions up to `Version::MAX`.)
/// - Split the text data into better or optimal segments in order to reduce the number of bits required.
/// - Change the text or binary data to be shorter.
/// - Change the text to fit the character set of a particular segment mode (e.g. alphanumeric).
/// - Propagate the error upward to the caller/user.
#[derive(Debug, Clone)]
pub struct DataTooLong(String);

impl std::error::Error for DataTooLong {
        fn description(&self) -> &str {
                &self.0
        }
}

impl std::fmt::Display for DataTooLong {
        fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
                f.write_str(&self.0)
        }
}


/// A number between 1 and 40 (inclusive).
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
pub struct Version(u8);

impl Version {
        /// The minimum version number supported in the QR Code Model 2 standard.
        pub const MIN: Version = Version( 1);
        
        /// The maximum version number supported in the QR Code Model 2 standard.
        pub const MAX: Version = Version(40);
        
        /// Creates a version object from the given number.
        /// 
        /// Panics if the number is outside the range [1, 40].
        pub fn new(ver: u8) -> Self {
                assert!(Version::MIN.value() <= ver && ver <= Version::MAX.value(), "Version number out of range");
                Self(ver)
        }
        
        /// Returns the value, which is in the range [1, 40].
        pub fn value(self) -> u8 {
                self.0
        }
}


/// A number between 0 and 7 (inclusive).
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
pub struct Mask(u8);

impl Mask {
        /// Creates a mask object from the given number.
        /// 
        /// Panics if the number is outside the range [0, 7].
        pub fn new(mask: u8) -> Self {
                assert!(mask <= 7, "Mask value out of range");
                Self(mask)
        }
        
        /// Returns the value, which is in the range [0, 7].
        pub fn value(self) -> u8 {
                self.0
        }
}


// Returns true iff the i'th bit of x is set to 1.
fn get_bit(x: u32, i: i32) -> bool {
        (x >> i) & 1 != 0
}