license and readme

Cargo.lock

@@ -20,6 +20,7 @@ version = "0.1.0"
 dependencies = [
  "arrayvec",
  "num-traits",
+ "ufmt",
 ]
 
 [[package]]
@@ -30,3 +31,65 @@ checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
 dependencies = [
  "autocfg",
 ]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.95"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "02b3e5e68a3a1a02aad3ec490a98007cbc13c37cbe84a3cd7b8e406d76e7f778"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1885c039570dc00dcb4ff087a89e185fd56bae234ddc7f056a945bf36467248d"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "ufmt"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a64846ec02b57e9108d6469d98d1648782ad6bb150a95a9baac26900bbeab9d"
+dependencies = [
+ "ufmt-macros",
+ "ufmt-write",
+]
+
+[[package]]
+name = "ufmt-macros"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d337d3be617449165cb4633c8dece429afd83f84051024079f97ad32a9663716"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "ufmt-write"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e87a2ed6b42ec5e28cc3b94c09982969e9227600b2e3dcbc1db927a84c06bd69"
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a5f39404a5da50712a4c1eecf25e90dd62b613502b7e925fd4e4d19b5c96512"

Cargo.toml

@@ -5,6 +5,10 @@ edition = "2021"
 
 [dependencies]
 num-traits = { version = "0.2.19", default-features = false }
+ufmt = { version = "0.2.0", optional = true }
 
 [dev-dependencies]
 arrayvec = { version = "0.7.6", default-features = false }
+
+[features]
+ufmt = ["dep:ufmt"]

LICENSE-APACHE

@@ -0,0 +1,201 @@
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README.md

@@ -0,0 +1,3 @@
+# Decimal numbers and simple calculator math for Rust core projects
+
+Tests can be run on `std` but library is designed for `core` only for embedded systems.

src/calc.rs

@@ -1,38 +1,59 @@
-use core::{convert::Infallible, error::Error, fmt::Display};
+use core::{convert::Infallible, fmt::Display, marker::PhantomData};
 
-use num_traits::{PrimInt, Unsigned};
+use num_traits::{float::FloatCore, PrimInt, Unsigned};
+#[cfg(feature = "ufmt")]
+use ufmt::derive::uDebug;
 
 use crate::{Decimal, DecimalError};
 
 #[derive(Debug)]
+#[cfg_attr(feature = "ufmt", derive(uDebug))]
 pub enum StackCalcError {
     StackOverflow,
     StackUnderflow,
     DecimalError(DecimalError),
 }
 
-impl Error for StackCalcError {}
 impl Display for StackCalcError {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match self {
             StackCalcError::StackOverflow => f.write_str("stack overflow"),
             StackCalcError::StackUnderflow => f.write_str("stack underflow"),
-            StackCalcError::DecimalError(de) => de.fmt(f),
+            StackCalcError::DecimalError(de) => Display::fmt(de, f),
         }
     }
 }
 
 #[derive(Debug, Clone)]
-pub struct StackCalc<const SS: usize = 2, const DS: usize = 5, E = u16> {
+pub struct StackCalc<F: FloatCore, const STACK: usize = 2, const DSIZE: usize = 5, EXP = u16> {
-    stack: [Decimal<DS, E>; SS],
+    stack: [Decimal<DSIZE, EXP>; STACK],
     index: usize,
+    phantom: PhantomData<F>,
 }
 
-impl<const SS: usize, const DS: usize, E: PrimInt> Default for StackCalc<SS, DS, E> {
+#[cfg(feature = "ufmt")]
+impl<F: FloatCore, const STACK: usize, const DSIZE: usize, EXP: ufmt::uDebug> ufmt::uDebug
+    for StackCalc<F, STACK, DSIZE, EXP>
+{
+    fn fmt<W>(&self, f: &mut ufmt::Formatter<'_, W>) -> Result<(), W::Error>
+    where
+        W: ufmt::uWrite + ?Sized,
+    {
+        f.debug_struct("StackCalc")?
+            .field("stack", &self.stack.as_slice())?
+            .field("index", &self.index)?
+            .finish()
+    }
+}
+
+impl<F: FloatCore, const STACK: usize, const DSIZE: usize, EXP: PrimInt> Default
+    for StackCalc<F, STACK, DSIZE, EXP>
+{
     fn default() -> Self {
         StackCalc {
-            stack: [Decimal::default(); SS],
+            stack: [Decimal::default(); STACK],
             index: 0,
+            phantom: PhantomData,
         }
     }
 }
@@ -49,12 +70,41 @@ impl From<Infallible> for StackCalcError {
     }
 }
 
-impl<const SS: usize, const DS: usize, E: PrimInt + Unsigned> StackCalc<SS, DS, E> {
+impl<F: FloatCore, const STACK: usize, const DSIZE: usize, EXP: PrimInt + Unsigned>
+    StackCalc<F, STACK, DSIZE, EXP>
+{
+    pub fn is_full(&self) -> bool {
+        self.index == STACK
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.index == 0
+    }
+
+    pub fn len(&self) -> usize {
+        self.index
+    }
+
+    pub fn reset(&mut self) {
+        self.index = 0;
+    }
+
+    pub fn last(&self) -> Option<Decimal<DSIZE, EXP>> {
+        if self.is_empty() {
+            return None;
+        }
+        Some(self.stack[self.index - 1])
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &Decimal<DSIZE, EXP>> {
+        self.stack.iter().take(self.index)
+    }
+
     pub fn push(
         &mut self,
-        val: impl TryInto<Decimal<DS, E>, Error: Into<StackCalcError>>,
+        val: impl TryInto<Decimal<DSIZE, EXP>, Error: Into<StackCalcError>>,
     ) -> Result<(), StackCalcError> {
-        if self.index == SS {
+        if self.is_full() {
             return Err(StackCalcError::StackOverflow);
         }
         self.stack[self.index] = val.try_into().map_err(Into::into)?;
@@ -62,23 +112,47 @@ impl<const SS: usize, const DS: usize, E: PrimInt + Unsigned> StackCalc<SS, DS,
         Ok(())
     }
 
-    pub fn pop(&mut self) -> Result<Decimal<DS, E>, StackCalcError> {
+    pub fn pop(&mut self) -> Result<Decimal<DSIZE, EXP>, StackCalcError> {
-        if self.index == 0 {
+        if self.is_empty() {
             return Err(StackCalcError::StackUnderflow);
         }
         self.index -= 1;
         Ok(self.stack[self.index])
     }
 
-    pub fn add(&mut self) -> Result<Decimal<DS, E>, StackCalcError> {
+    fn pop_pair_float(&mut self) -> Result<(F, F), StackCalcError> {
         let a = self.pop()?;
         let b = self.pop()?;
-        let a = f64::try_from(a)?;
+        let a = a.to_float::<F>()?;
-        let b = f64::try_from(b)?;
+        let b = b.to_float::<F>()?;
-        let res = Decimal::try_from(a + b)?;
+        Ok((a, b))
+    }
+
+    fn calc_pair_float(
+        &mut self,
+        f: impl FnOnce(F, F) -> Result<F, StackCalcError>,
+    ) -> Result<Decimal<DSIZE, EXP>, StackCalcError> {
+        let (a, b) = self.pop_pair_float()?;
+        let res = Decimal::from_float(f(a, b)?)?;
         self.push(res)?;
         Ok(res)
     }
+
+    pub fn add(&mut self) -> Result<Decimal<DSIZE, EXP>, StackCalcError> {
+        self.calc_pair_float(|a, b| Ok(b + a))
+    }
+
+    pub fn sub(&mut self) -> Result<Decimal<DSIZE, EXP>, StackCalcError> {
+        self.calc_pair_float(|a, b| Ok(b - a))
+    }
+
+    pub fn mul(&mut self) -> Result<Decimal<DSIZE, EXP>, StackCalcError> {
+        self.calc_pair_float(|a, b| Ok(b * a))
+    }
+
+    pub fn div(&mut self) -> Result<Decimal<DSIZE, EXP>, StackCalcError> {
+        self.calc_pair_float(|a, b| Ok(b / a))
+    }
 }
 
 #[cfg(test)]
@@ -86,7 +160,7 @@ mod tests {
     use super::*;
     #[test]
     fn test_add() -> Result<(), StackCalcError> {
-        let mut calc = StackCalc::<3, 7>::default();
+        let mut calc = StackCalc::<f64, 3, 7>::default();
         calc.push(Decimal::default())?;
         calc.push(1337.42)?;
         assert_eq!(calc.add()?, Decimal::try_from(1337.42)?);
@@ -98,12 +172,26 @@ mod tests {
             calc.push(3.0).unwrap_err(),
             StackCalcError::StackOverflow
         ));
-        assert_eq!(calc.add()?, Decimal::try_from(5.0)?);
+        calc.add()?;
-        assert_eq!(calc.add()?, Decimal::try_from(1337.42 * 2.0 + 5.0)?);
+        assert_eq!(calc.last().unwrap(), Decimal::try_from(5.0)?);
+        calc.add()?;
+        assert_eq!(
+            calc.last().unwrap(),
+            Decimal::try_from(1337.42 * 2.0 + 5.0)?
+        );
         assert!(matches!(
             calc.add().unwrap_err(),
             StackCalcError::StackUnderflow
         ));
         Ok(())
     }
+
+    #[test]
+    fn test_add_10() -> Result<(), StackCalcError> {
+        let mut calc = StackCalc::<f32, 3, 5>::default();
+        calc.push(Decimal::new(false, [3, 0, 0, 0, 0], false, 0))?;
+        calc.push(Decimal::new(false, [7, 0, 0, 0, 0], false, 0))?;
+        assert_eq!(calc.add()?, Decimal::new(false, [1, 0, 0, 0, 0], false, 1));
+        Ok(())
+    }
 }

src/lib.rs

@@ -2,18 +2,21 @@
 
 pub mod calc;
 
-use core::{error::Error, fmt::Display};
+use core::fmt::Display;
-#[cfg(not(test))]
 use num_traits::float::FloatCore;
 use num_traits::{one, zero, PrimInt, Unsigned};
+#[cfg(feature = "ufmt")]
+use ufmt::derive::uDebug;
+#[cfg(feature = "ufmt")]
+use ufmt::{uDebug, uDisplay, uwrite};
 
 #[derive(Debug)]
+#[cfg_attr(feature = "ufmt", derive(uDebug))]
 pub enum DecimalError {
     ExponentOverflow,
     NotANumber,
 }
 
-impl Error for DecimalError {}
 impl Display for DecimalError {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match self {
@@ -24,30 +27,140 @@ impl Display for DecimalError {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct Decimal<const S: usize = 5, E = u16> {
+pub struct Decimal<const SIZE: usize = 5, EXP = u16> {
-    pub minus: bool,
+    minus: bool,
-    pub significant: [u8; S],
+    significant: [u8; SIZE],
-    pub minus_exponent: bool,
+    minus_exponent: bool,
-    pub exponent: E,
+    exponent: EXP,
 }
 
-impl<const S: usize, E: PrimInt> Default for Decimal<S, E> {
+#[cfg(feature = "ufmt")]
+impl<const SIZE: usize, EXP: uDebug> uDebug for Decimal<SIZE, EXP> {
+    fn fmt<W>(&self, f: &mut ufmt::Formatter<'_, W>) -> Result<(), W::Error>
+    where
+        W: ufmt::uWrite + ?Sized,
+    {
+        f.debug_struct("Decimal")?
+            .field("minus", &self.minus)?
+            .field("significant", &self.significant.as_slice())?
+            .field("minus_exponent", &self.minus_exponent)?
+            .field("exponent", &self.exponent)?
+            .finish()
+    }
+}
+
+impl<const SIZE: usize, EXP: PrimInt + Unsigned> Decimal<SIZE, EXP> {
+    pub fn new(minus: bool, significant: [u8; SIZE], minus_exponent: bool, exponent: EXP) -> Self {
+        for s in significant {
+            assert!(s < 10, "bad significant");
+        }
+        Decimal {
+            minus,
+            significant,
+            minus_exponent,
+            exponent,
+        }
+    }
+
+    pub fn into_parts(self) -> (bool, [u8; SIZE], bool, EXP) {
+        (
+            self.minus,
+            self.significant,
+            self.minus_exponent,
+            self.exponent,
+        )
+    }
+
+    pub fn from_float<F: FloatCore>(mut f: F) -> Result<Self, DecimalError> {
+        if !f.is_finite() {
+            return Err(DecimalError::NotANumber);
+        }
+
+        let minus = f.is_sign_negative();
+        if minus {
+            f = f * F::from(-1).unwrap();
+        }
+
+        let mut significant = [0; SIZE];
+        let mut exponent: EXP = zero();
+        let minus_exponent = f < one() && f > zero();
+        let ten = F::from(10).unwrap();
+
+        if !f.is_zero() {
+            while f >= ten {
+                f = f / ten;
+                exponent = exponent
+                    .checked_add(&one())
+                    .ok_or(DecimalError::ExponentOverflow)?;
+            }
+            while f < one() {
+                f = f * ten;
+                exponent = exponent
+                    .checked_add(&one())
+                    .ok_or(DecimalError::ExponentOverflow)?;
+            }
+        }
+
+        for i in 0..SIZE {
+            significant[i] = f.trunc().to_u8().unwrap();
+            f = f.fract() * ten;
+        }
+
+        Ok(Decimal {
+            minus,
+            significant,
+            minus_exponent,
+            exponent,
+        })
+    }
+
+    pub fn to_float<F: FloatCore>(&self) -> Result<F, DecimalError> {
+        let Decimal {
+            minus,
+            significant,
+            minus_exponent,
+            exponent,
+        } = *self;
+
+        let mut e = exponent.to_i32().ok_or(DecimalError::ExponentOverflow)?;
+        if minus_exponent {
+            e = -e;
+        }
+        let e = F::from(10).unwrap().powi(e);
+
+        let mut f: F = zero();
+
+        for i in (0..SIZE).rev() {
+            f = f / F::from(10).unwrap();
+            let s = significant[i];
+            f = f + F::from(s).unwrap() * e;
+        }
+
+        if minus {
+            f = f * F::from(-1).unwrap();
+        }
+
+        Ok(f)
+    }
+}
+
+impl<const SIZE: usize, EXP: PrimInt> Default for Decimal<SIZE, EXP> {
     fn default() -> Self {
         Decimal {
             minus: false,
-            significant: [0; S],
+            significant: [0; SIZE],
             minus_exponent: false,
             exponent: zero(),
         }
     }
 }
 
-impl<const S: usize, E: Display> Display for Decimal<S, E> {
+impl<const SIZE: usize, EXP: Display> Display for Decimal<SIZE, EXP> {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         if self.minus {
             write!(f, "-")?;
         }
-        for i in 0..S {
+        for i in 0..SIZE {
             write!(f, "{}", self.significant[i])?;
             if i == 0 {
                 write!(f, ".")?;
@@ -61,80 +174,58 @@ impl<const S: usize, E: Display> Display for Decimal<S, E> {
     }
 }
 
-impl<const S: usize, E: PrimInt + Unsigned> TryFrom<f64> for Decimal<S, E> {
+#[cfg(feature = "ufmt")]
-    type Error = DecimalError;
+impl<const SIZE: usize, EXP: Display + uDisplay> uDisplay for Decimal<SIZE, EXP> {
-
+    fn fmt<W>(&self, f: &mut ufmt::Formatter<'_, W>) -> Result<(), W::Error>
-    fn try_from(mut f: f64) -> Result<Self, Self::Error> {
+    where
-        if !f.is_finite() {
+        W: ufmt::uWrite + ?Sized,
-            return Err(DecimalError::NotANumber);
+    {
+        if self.minus {
+            uwrite!(f, "-")?;
         }
-        let minus = f.is_sign_negative();
+        for i in 0..SIZE {
-        if minus {
+            uwrite!(f, "{}", self.significant[i])?;
-            f *= -1.0;
+            if i == 0 {
+                uwrite!(f, ".")?;
             }
-        let mut exponent: E = zero();
-        let minus_exponent = f < 1.0 && f > 0.0;
-        while f > 10.0 {
-            f /= 10.0;
-            exponent = exponent
-                .checked_add(&one())
-                .ok_or(DecimalError::ExponentOverflow)?;
         }
-        while f < 1.0 {
+        uwrite!(f, "e")?;
-            if f == f * 10.0 {
+        if self.minus_exponent {
-                break;
+            uwrite!(f, "-")?;
         }
-            f *= 10.0;
+        uwrite!(f, "{}", self.exponent)
-            exponent = exponent
-                .checked_add(&one())
-                .ok_or(DecimalError::ExponentOverflow)?;
-        }
-        let mut significant = [0; S];
-        for i in 0..S {
-            let s = f as u8;
-            f *= 10.0;
-            f -= (s * 10) as f64;
-            significant[i] = s;
-        }
-        Ok(Decimal {
-            minus,
-            significant,
-            minus_exponent,
-            exponent,
-        })
     }
 }
 
-impl<const S: usize, E: PrimInt + Unsigned> TryFrom<Decimal<S, E>> for f64 {
+impl<const SIZE: usize, EXP: PrimInt + Unsigned> TryFrom<f32> for Decimal<SIZE, EXP> {
     type Error = DecimalError;
 
-    fn try_from(val: Decimal<S, E>) -> Result<Self, Self::Error> {
+    fn try_from(f: f32) -> Result<Self, Self::Error> {
-        let Decimal {
+        Self::from_float(f)
-            minus,
-            significant,
-            minus_exponent,
-            exponent,
-        } = val;
-
-        let mut e = exponent.to_i32().ok_or(DecimalError::ExponentOverflow)?;
-        if minus_exponent {
-            e = -e;
     }
-        let e = 10.0f64.powi(e);
+}
 
-        let mut f: f64 = 0.0;
+impl<const SIZE: usize, EXP: PrimInt + Unsigned> TryFrom<f64> for Decimal<SIZE, EXP> {
+    type Error = DecimalError;
 
-        for i in (0..S).rev() {
+    fn try_from(f: f64) -> Result<Self, Self::Error> {
-            f /= 10.0;
+        Self::from_float(f)
-            let s = significant[i];
-            f += (s as f64) * e;
     }
+}
 
-        if minus {
+impl<const SIZE: usize, EXP: PrimInt + Unsigned> TryFrom<Decimal<SIZE, EXP>> for f32 {
-            f *= -1.0;
+    type Error = DecimalError;
+
+    fn try_from(val: Decimal<SIZE, EXP>) -> Result<Self, Self::Error> {
+        val.to_float()
     }
+}
 
-        Ok(f)
+impl<const SIZE: usize, EXP: PrimInt + Unsigned> TryFrom<Decimal<SIZE, EXP>> for f64 {
+    type Error = DecimalError;
+
+    fn try_from(val: Decimal<SIZE, EXP>) -> Result<Self, Self::Error> {
+        val.to_float()
     }
 }
 
@@ -143,6 +234,11 @@ mod tests {
     use super::*;
     use arrayvec::ArrayString;
 
+    fn round_f(f: f64, d: i32) -> f64 {
+        let m = 10.0.powi(d);
+        (f * m).round() / m
+    }
+
     #[test]
     fn float_to_decimal_zero() {
         let dec = Decimal::<5>::try_from(0.0).unwrap();
@@ -152,6 +248,25 @@ mod tests {
         assert_eq!(dec.exponent, 0)
     }
 
+    #[test]
+    fn float_to_decimal_10() {
+        let dec = Decimal::<5>::try_from(10.0).unwrap();
+        assert!(!dec.minus);
+        assert_eq!(dec.significant, [1, 0, 0, 0, 0]);
+        assert!(!dec.minus_exponent);
+        assert_eq!(dec.exponent, 1)
+    }
+
+    #[test]
+    #[ignore = "dbg![1.14f32.fract()]; // 0.13999999"]
+    fn float_to_decimal_114() {
+        let dec = Decimal::<5>::try_from(114.0f32).unwrap();
+        assert!(!dec.minus);
+        assert_eq!(dec.significant, [1, 1, 4, 0, 0]);
+        assert!(!dec.minus_exponent);
+        assert_eq!(dec.exponent, 2)
+    }
+
     #[test]
     fn float_to_decimal_pos_big() {
         let dec = Decimal::<7>::try_from(1337.42).unwrap();
@@ -250,10 +365,13 @@ mod tests {
     #[test]
     fn decimal_to_float_small() {
         let mut dec = Decimal::<7, u8>::default();
-        dec.significant = [1, 3, 3, 7, 4, 2, 0];
+        dec.significant = [1, 3, 3, 7, 4, 2, 1];
         dec.minus_exponent = true;
         dec.exponent = 2;
-        assert_eq!(f64::try_from(dec).unwrap(), 0.0133742);
+        assert_eq!(
+            round_f(f64::try_from(dec).unwrap(), 8),
+            round_f(0.01337421, 8)
+        );
     }
 
     #[test]
@@ -269,10 +387,13 @@ mod tests {
     fn decimal_to_float_neg_small() {
         let mut dec = Decimal::<7, u8>::default();
         dec.minus = true;
-        dec.significant = [1, 3, 3, 7, 4, 2, 0];
+        dec.significant = [1, 3, 3, 7, 4, 2, 1];
         dec.minus_exponent = true;
         dec.exponent = 2;
-        assert_eq!(f64::try_from(dec).unwrap(), -0.0133742);
+        assert_eq!(
+            round_f(f64::try_from(dec).unwrap(), 8),
+            round_f(-0.01337421, 8)
+        );
     }
 
     #[test]