ableos/qrcode-rust/src/types.rs
2022-07-29 09:46:09 -05:00

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use crate::cast::As;
use core::cmp::{Ordering, PartialOrd};
use core::default::Default;
use core::fmt::{Display, Error, Formatter};
use core::ops::Not;
//------------------------------------------------------------------------------
//{{{ QrResult
/// `QrError` encodes the error encountered when generating a QR code.
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum QrError {
/// The data is too long to encode into a QR code for the given version.
DataTooLong,
/// The provided version / error correction level combination is invalid.
InvalidVersion,
/// Some characters in the data cannot be supported by the provided QR code
/// version.
UnsupportedCharacterSet,
/// The provided ECI designator is invalid. A valid designator should be
/// between 0 and 999999.
InvalidEciDesignator,
/// A character not belonging to the character set is found.
InvalidCharacter,
}
impl Display for QrError {
fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error> {
let msg = match *self {
QrError::DataTooLong => "data too long",
QrError::InvalidVersion => "invalid version",
QrError::UnsupportedCharacterSet => "unsupported character set",
QrError::InvalidEciDesignator => "invalid ECI designator",
QrError::InvalidCharacter => "invalid character",
};
fmt.write_str(msg)
}
}
/// `QrResult` is a convenient alias for a QR code generation result.
pub type QrResult<T> = Result<T, QrError>;
//}}}
//------------------------------------------------------------------------------
//{{{ Color
/// The color of a module.
#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
pub enum Color {
/// The module is light colored.
Light,
/// The module is dark colored.
Dark,
}
impl Color {
/// Selects a value according to color of the module. Equivalent to
/// `if self != Color::Light { dark } else { light }`.
///
/// # Examples
///
/// ```rust
/// # use qrcode::types::Color;
/// assert_eq!(Color::Light.select(1, 0), 0);
/// assert_eq!(Color::Dark.select("black", "white"), "black");
/// ```
pub fn select<T>(self, dark: T, light: T) -> T {
match self {
Color::Light => light,
Color::Dark => dark,
}
}
}
impl Not for Color {
type Output = Self;
fn not(self) -> Self {
match self {
Color::Light => Color::Dark,
Color::Dark => Color::Light,
}
}
}
//}}}
//------------------------------------------------------------------------------
//{{{ Error correction level
/// The error correction level. It allows the original information be recovered
/// even if parts of the code is damaged.
#[derive(Debug, PartialEq, Eq, Copy, Clone, PartialOrd, Ord)]
pub enum EcLevel {
/// Low error correction. Allows up to 7% of wrong blocks.
L = 0,
/// Medium error correction (default). Allows up to 15% of wrong blocks.
M = 1,
/// "Quartile" error correction. Allows up to 25% of wrong blocks.
Q = 2,
/// High error correction. Allows up to 30% of wrong blocks.
H = 3,
}
//}}}
//------------------------------------------------------------------------------
//{{{ Version
/// In QR code terminology, `Version` means the size of the generated image.
/// Larger version means the size of code is larger, and therefore can carry
/// more information.
///
/// The smallest version is `Version::Normal(1)` of size 21×21, and the largest
/// is `Version::Normal(40)` of size 177×177.
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum Version {
/// A normal QR code version. The parameter should be between 1 and 40.
Normal(i16),
/// A Micro QR code version. The parameter should be between 1 and 4.
Micro(i16),
}
impl Version {
/// Get the number of "modules" on each size of the QR code, i.e. the width
/// and height of the code.
pub fn width(self) -> i16 {
match self {
Version::Normal(v) => v * 4 + 17,
Version::Micro(v) => v * 2 + 9,
}
}
/// Obtains an object from a hard-coded table.
///
/// The table must be a 44×4 array. The outer array represents the content
/// for each version. The first 40 entry corresponds to QR code versions 1
/// to 40, and the last 4 corresponds to Micro QR code version 1 to 4. The
/// inner array represents the content in each error correction level, in
/// the order [L, M, Q, H].
///
/// # Errors
///
/// If the entry compares equal to the default value of `T`, this method
/// returns `Err(QrError::InvalidVersion)`.
pub fn fetch<T>(self, ec_level: EcLevel, table: &[[T; 4]]) -> QrResult<T>
where
T: PartialEq + Default + Copy,
{
match self {
Version::Normal(v @ 1..=40) => {
return Ok(table[(v - 1).as_usize()][ec_level as usize]);
}
Version::Micro(v @ 1..=4) => {
let obj = table[(v + 39).as_usize()][ec_level as usize];
if obj != T::default() {
return Ok(obj);
}
}
_ => {}
}
Err(QrError::InvalidVersion)
}
/// The number of bits needed to encode the mode indicator.
pub fn mode_bits_count(self) -> usize {
match self {
Version::Micro(a) => (a - 1).as_usize(),
_ => 4,
}
}
/// Checks whether is version refers to a Micro QR code.
pub fn is_micro(self) -> bool {
match self {
Version::Normal(_) => false,
Version::Micro(_) => true,
}
}
}
//}}}
//------------------------------------------------------------------------------
//{{{ Mode indicator
/// The mode indicator, which specifies the character set of the encoded data.
#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum Mode {
/// The data contains only characters 0 to 9.
Numeric,
/// The data contains only uppercase letters (AZ), numbers (09) and a few
/// punctuations marks (space, `$`, `%`, `*`, `+`, `-`, `.`, `/`, `:`).
Alphanumeric,
/// The data contains arbitrary binary data.
Byte,
/// The data contains Shift-JIS-encoded double-byte text.
Kanji,
}
impl Mode {
/// Computes the number of bits needed to encode the data length.
///
/// use qrcode::types::{Version, Mode};
///
/// assert_eq!(Mode::Numeric.length_bits_count(Version::Normal(1)), 10);
///
/// This method will return `Err(QrError::UnsupportedCharacterSet)` if the
/// mode is not supported in the given version.
pub fn length_bits_count(self, version: Version) -> usize {
match version {
Version::Micro(a) => {
let a = a.as_usize();
match self {
Mode::Numeric => 2 + a,
Mode::Alphanumeric | Mode::Byte => 1 + a,
Mode::Kanji => a,
}
}
Version::Normal(1..=9) => match self {
Mode::Numeric => 10,
Mode::Alphanumeric => 9,
Mode::Byte | Mode::Kanji => 8,
},
Version::Normal(10..=26) => match self {
Mode::Numeric => 12,
Mode::Alphanumeric => 11,
Mode::Byte => 16,
Mode::Kanji => 10,
},
Version::Normal(_) => match self {
Mode::Numeric => 14,
Mode::Alphanumeric => 13,
Mode::Byte => 16,
Mode::Kanji => 12,
},
}
}
/// Computes the number of bits needed to some data of a given raw length.
///
/// use qrcode::types::Mode;
///
/// assert_eq!(Mode::Numeric.data_bits_count(7), 24);
///
/// Note that in Kanji mode, the `raw_data_len` is the number of Kanjis,
/// i.e. half the total size of bytes.
pub fn data_bits_count(self, raw_data_len: usize) -> usize {
match self {
Mode::Numeric => (raw_data_len * 10 + 2) / 3,
Mode::Alphanumeric => (raw_data_len * 11 + 1) / 2,
Mode::Byte => raw_data_len * 8,
Mode::Kanji => raw_data_len * 13,
}
}
/// Find the lowest common mode which both modes are compatible with.
///
/// use qrcode::types::Mode;
///
/// let a = Mode::Numeric;
/// let b = Mode::Kanji;
/// let c = a.max(b);
/// assert!(a <= c);
/// assert!(b <= c);
///
pub fn max(self, other: Self) -> Self {
match self.partial_cmp(&other) {
Some(Ordering::Less) | Some(Ordering::Equal) => other,
Some(Ordering::Greater) => self,
None => Mode::Byte,
}
}
}
impl PartialOrd for Mode {
/// Defines a partial ordering between modes. If `a <= b`, then `b` contains
/// a superset of all characters supported by `a`.
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
match (*self, *other) {
(Mode::Numeric, Mode::Alphanumeric)
| (Mode::Numeric, Mode::Byte)
| (Mode::Alphanumeric, Mode::Byte)
| (Mode::Kanji, Mode::Byte) => Some(Ordering::Less),
(Mode::Alphanumeric, Mode::Numeric)
| (Mode::Byte, Mode::Numeric)
| (Mode::Byte, Mode::Alphanumeric)
| (Mode::Byte, Mode::Kanji) => Some(Ordering::Greater),
(a, b) if a == b => Some(Ordering::Equal),
_ => None,
}
}
}
#[cfg(test)]
mod mode_tests {
use crate::types::Mode::{Alphanumeric, Byte, Kanji, Numeric};
#[test]
fn test_mode_order() {
assert!(Numeric < Alphanumeric);
assert!(Byte > Kanji);
assert!(!(Numeric < Kanji));
assert!(!(Numeric >= Kanji));
}
#[test]
fn test_max() {
assert_eq!(Byte.max(Kanji), Byte);
assert_eq!(Numeric.max(Alphanumeric), Alphanumeric);
assert_eq!(Alphanumeric.max(Alphanumeric), Alphanumeric);
assert_eq!(Numeric.max(Kanji), Byte);
assert_eq!(Kanji.max(Numeric), Byte);
assert_eq!(Alphanumeric.max(Numeric), Alphanumeric);
assert_eq!(Kanji.max(Kanji), Kanji);
}
}
//}}}