327 lines
10 KiB
Rust
327 lines
10 KiB
Rust
use crate::cast::As;
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use core::cmp::{Ordering, PartialOrd};
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use core::default::Default;
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use core::fmt::{Display, Error, Formatter};
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use core::ops::Not;
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//------------------------------------------------------------------------------
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//{{{ QrResult
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/// `QrError` encodes the error encountered when generating a QR code.
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#[derive(Debug, PartialEq, Eq, Copy, Clone)]
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pub enum QrError {
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/// The data is too long to encode into a QR code for the given version.
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DataTooLong,
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/// The provided version / error correction level combination is invalid.
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InvalidVersion,
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/// Some characters in the data cannot be supported by the provided QR code
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/// version.
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UnsupportedCharacterSet,
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/// The provided ECI designator is invalid. A valid designator should be
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/// between 0 and 999999.
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InvalidEciDesignator,
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/// A character not belonging to the character set is found.
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InvalidCharacter,
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}
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impl Display for QrError {
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fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error> {
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let msg = match *self {
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QrError::DataTooLong => "data too long",
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QrError::InvalidVersion => "invalid version",
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QrError::UnsupportedCharacterSet => "unsupported character set",
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QrError::InvalidEciDesignator => "invalid ECI designator",
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QrError::InvalidCharacter => "invalid character",
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};
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fmt.write_str(msg)
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}
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}
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/// `QrResult` is a convenient alias for a QR code generation result.
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pub type QrResult<T> = Result<T, QrError>;
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//}}}
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//------------------------------------------------------------------------------
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//{{{ Color
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/// The color of a module.
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#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
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pub enum Color {
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/// The module is light colored.
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Light,
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/// The module is dark colored.
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Dark,
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}
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impl Color {
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/// Selects a value according to color of the module. Equivalent to
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/// `if self != Color::Light { dark } else { light }`.
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///
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/// # Examples
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///
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/// ```rust
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/// # use qrcode::types::Color;
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/// assert_eq!(Color::Light.select(1, 0), 0);
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/// assert_eq!(Color::Dark.select("black", "white"), "black");
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/// ```
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pub fn select<T>(self, dark: T, light: T) -> T {
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match self {
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Color::Light => light,
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Color::Dark => dark,
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}
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}
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}
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impl Not for Color {
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type Output = Self;
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fn not(self) -> Self {
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match self {
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Color::Light => Color::Dark,
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Color::Dark => Color::Light,
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}
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}
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}
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//}}}
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//------------------------------------------------------------------------------
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//{{{ Error correction level
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/// The error correction level. It allows the original information be recovered
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/// even if parts of the code is damaged.
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#[derive(Debug, PartialEq, Eq, Copy, Clone, PartialOrd, Ord)]
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pub enum EcLevel {
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/// Low error correction. Allows up to 7% of wrong blocks.
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L = 0,
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/// Medium error correction (default). Allows up to 15% of wrong blocks.
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M = 1,
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/// "Quartile" error correction. Allows up to 25% of wrong blocks.
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Q = 2,
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/// High error correction. Allows up to 30% of wrong blocks.
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H = 3,
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}
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//}}}
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//------------------------------------------------------------------------------
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//{{{ Version
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/// In QR code terminology, `Version` means the size of the generated image.
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/// Larger version means the size of code is larger, and therefore can carry
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/// more information.
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///
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/// The smallest version is `Version::Normal(1)` of size 21×21, and the largest
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/// is `Version::Normal(40)` of size 177×177.
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#[derive(Debug, PartialEq, Eq, Copy, Clone)]
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pub enum Version {
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/// A normal QR code version. The parameter should be between 1 and 40.
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Normal(i16),
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/// A Micro QR code version. The parameter should be between 1 and 4.
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Micro(i16),
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}
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impl Version {
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/// Get the number of "modules" on each size of the QR code, i.e. the width
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/// and height of the code.
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pub fn width(self) -> i16 {
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match self {
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Version::Normal(v) => v * 4 + 17,
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Version::Micro(v) => v * 2 + 9,
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}
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}
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/// Obtains an object from a hard-coded table.
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///
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/// The table must be a 44×4 array. The outer array represents the content
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/// for each version. The first 40 entry corresponds to QR code versions 1
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/// to 40, and the last 4 corresponds to Micro QR code version 1 to 4. The
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/// inner array represents the content in each error correction level, in
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/// the order [L, M, Q, H].
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///
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/// # Errors
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///
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/// If the entry compares equal to the default value of `T`, this method
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/// returns `Err(QrError::InvalidVersion)`.
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pub fn fetch<T>(self, ec_level: EcLevel, table: &[[T; 4]]) -> QrResult<T>
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where
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T: PartialEq + Default + Copy,
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{
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match self {
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Version::Normal(v @ 1..=40) => {
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return Ok(table[(v - 1).as_usize()][ec_level as usize]);
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}
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Version::Micro(v @ 1..=4) => {
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let obj = table[(v + 39).as_usize()][ec_level as usize];
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if obj != T::default() {
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return Ok(obj);
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}
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}
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_ => {}
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}
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Err(QrError::InvalidVersion)
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}
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/// The number of bits needed to encode the mode indicator.
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pub fn mode_bits_count(self) -> usize {
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match self {
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Version::Micro(a) => (a - 1).as_usize(),
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_ => 4,
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}
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}
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/// Checks whether is version refers to a Micro QR code.
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pub fn is_micro(self) -> bool {
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match self {
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Version::Normal(_) => false,
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Version::Micro(_) => true,
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}
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}
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}
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//}}}
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//------------------------------------------------------------------------------
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//{{{ Mode indicator
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/// The mode indicator, which specifies the character set of the encoded data.
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#[derive(Debug, PartialEq, Eq, Copy, Clone)]
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pub enum Mode {
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/// The data contains only characters 0 to 9.
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Numeric,
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/// The data contains only uppercase letters (A–Z), numbers (0–9) and a few
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/// punctuations marks (space, `$`, `%`, `*`, `+`, `-`, `.`, `/`, `:`).
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Alphanumeric,
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/// The data contains arbitrary binary data.
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Byte,
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/// The data contains Shift-JIS-encoded double-byte text.
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Kanji,
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}
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impl Mode {
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/// Computes the number of bits needed to encode the data length.
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///
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/// use qrcode::types::{Version, Mode};
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///
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/// assert_eq!(Mode::Numeric.length_bits_count(Version::Normal(1)), 10);
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///
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/// This method will return `Err(QrError::UnsupportedCharacterSet)` if the
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/// mode is not supported in the given version.
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pub fn length_bits_count(self, version: Version) -> usize {
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match version {
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Version::Micro(a) => {
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let a = a.as_usize();
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match self {
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Mode::Numeric => 2 + a,
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Mode::Alphanumeric | Mode::Byte => 1 + a,
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Mode::Kanji => a,
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}
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}
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Version::Normal(1..=9) => match self {
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Mode::Numeric => 10,
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Mode::Alphanumeric => 9,
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Mode::Byte | Mode::Kanji => 8,
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},
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Version::Normal(10..=26) => match self {
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Mode::Numeric => 12,
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Mode::Alphanumeric => 11,
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Mode::Byte => 16,
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Mode::Kanji => 10,
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},
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Version::Normal(_) => match self {
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Mode::Numeric => 14,
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Mode::Alphanumeric => 13,
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Mode::Byte => 16,
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Mode::Kanji => 12,
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},
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}
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}
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/// Computes the number of bits needed to some data of a given raw length.
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///
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/// use qrcode::types::Mode;
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///
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/// assert_eq!(Mode::Numeric.data_bits_count(7), 24);
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///
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/// Note that in Kanji mode, the `raw_data_len` is the number of Kanjis,
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/// i.e. half the total size of bytes.
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pub fn data_bits_count(self, raw_data_len: usize) -> usize {
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match self {
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Mode::Numeric => (raw_data_len * 10 + 2) / 3,
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Mode::Alphanumeric => (raw_data_len * 11 + 1) / 2,
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Mode::Byte => raw_data_len * 8,
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Mode::Kanji => raw_data_len * 13,
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}
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}
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/// Find the lowest common mode which both modes are compatible with.
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///
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/// use qrcode::types::Mode;
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///
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/// let a = Mode::Numeric;
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/// let b = Mode::Kanji;
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/// let c = a.max(b);
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/// assert!(a <= c);
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/// assert!(b <= c);
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///
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pub fn max(self, other: Self) -> Self {
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match self.partial_cmp(&other) {
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Some(Ordering::Less) | Some(Ordering::Equal) => other,
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Some(Ordering::Greater) => self,
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None => Mode::Byte,
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}
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}
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}
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impl PartialOrd for Mode {
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/// Defines a partial ordering between modes. If `a <= b`, then `b` contains
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/// a superset of all characters supported by `a`.
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fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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match (*self, *other) {
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(Mode::Numeric, Mode::Alphanumeric)
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| (Mode::Numeric, Mode::Byte)
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| (Mode::Alphanumeric, Mode::Byte)
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| (Mode::Kanji, Mode::Byte) => Some(Ordering::Less),
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(Mode::Alphanumeric, Mode::Numeric)
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| (Mode::Byte, Mode::Numeric)
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| (Mode::Byte, Mode::Alphanumeric)
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| (Mode::Byte, Mode::Kanji) => Some(Ordering::Greater),
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(a, b) if a == b => Some(Ordering::Equal),
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_ => None,
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}
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}
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}
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#[cfg(test)]
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mod mode_tests {
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use crate::types::Mode::{Alphanumeric, Byte, Kanji, Numeric};
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#[test]
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fn test_mode_order() {
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assert!(Numeric < Alphanumeric);
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assert!(Byte > Kanji);
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assert!(!(Numeric < Kanji));
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assert!(!(Numeric >= Kanji));
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}
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#[test]
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fn test_max() {
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assert_eq!(Byte.max(Kanji), Byte);
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assert_eq!(Numeric.max(Alphanumeric), Alphanumeric);
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assert_eq!(Alphanumeric.max(Alphanumeric), Alphanumeric);
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assert_eq!(Numeric.max(Kanji), Byte);
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assert_eq!(Kanji.max(Numeric), Byte);
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assert_eq!(Alphanumeric.max(Numeric), Alphanumeric);
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assert_eq!(Kanji.max(Kanji), Kanji);
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}
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}
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//}}}
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