From 9fa2793b24c748ad40a0771f2893d1b6d1fa9d96 Mon Sep 17 00:00:00 2001
From: Ryan Pitasky <ryanpitasky+github@gmail.com>
Date: Sun, 18 Aug 2024 19:06:30 -0400
Subject: [PATCH] Add digits and significant figures getters

---
 Cargo.toml      |  2 +-
 src/float.rs    | 50 +++++++++++++++++++++++++++++++++++++++++++------
 src/mantissa.rs | 24 ++++++++++++++++++++++++
 3 files changed, 69 insertions(+), 7 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 901b877..5bab706 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "tifloats"
-version = "2.3.0"
+version = "2.3.1"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 homepage = "https://github.com/TI-Toolkit/tifloats_lib_rs"
diff --git a/src/float.rs b/src/float.rs
index 6e26b5f..c9c0adb 100644
--- a/src/float.rs
+++ b/src/float.rs
@@ -1,9 +1,9 @@
+use crate::mantissa::Mantissa;
+use std::fmt::{Debug, Formatter};
 use std::{
     cmp::Ordering,
     ops::{Add, Div, Mul, Neg, Sub},
 };
-use std::fmt::{Debug, Formatter};
-use crate::mantissa::Mantissa;
 
 use bitflags::bitflags;
 
@@ -153,6 +153,19 @@ impl Float {
     pub fn is_complex_half(&self) -> bool {
         self.flags.contains(Flags::COMPLEX_HALF)
     }
+
+    pub fn digits(&self) -> Vec<u8> {
+        self.mantissa.digits()
+    }
+
+    pub fn significant_figures(&self) -> Vec<u8> {
+        let mut digits = self.mantissa.digits();
+
+        let new_length = digits.iter().rposition(|x| *x != 0).map_or(1, |i| i + 1);
+
+        digits.truncate(new_length);
+        digits
+    }
 }
 
 impl PartialOrd for Float {
@@ -302,7 +315,11 @@ impl Debug for Float {
             f.write_str("-")?;
         }
 
-        f.write_str(&format!("0x{} * 10 ^ {}", self.mantissa.to_dec().to_string(), (self.exponent as i8).wrapping_add(Float::EXPONENT_NORM as i8)))
+        f.write_str(&format!(
+            "0x{} * 10 ^ {}",
+            self.mantissa.to_dec().to_string(),
+            (self.exponent as i8).wrapping_add(Float::EXPONENT_NORM as i8)
+        ))
     }
 }
 
@@ -374,8 +391,29 @@ mod tests {
 
     #[test]
     fn debug() {
-        assert_eq!("0x50000000000000 * 10 ^ 5", format!("{:?}", tifloat!(0x50000000000000 * 10 ^ 5)));
-        assert_eq!("-0x50000000000000 * 10 ^ 5", format!("{:?}", tifloat!(-0x50000000000000 * 10 ^ 5)));
-        assert_eq!("0x50000000000000 * 10 ^ -5", format!("{:?}", tifloat!(0x50000000000000 * 10 ^ -5)));
+        assert_eq!(
+            "0x50000000000000 * 10 ^ 5",
+            format!("{:?}", tifloat!(0x50000000000000 * 10 ^ 5))
+        );
+        assert_eq!(
+            "-0x50000000000000 * 10 ^ 5",
+            format!("{:?}", tifloat!(-0x50000000000000 * 10 ^ 5))
+        );
+        assert_eq!(
+            "0x50000000000000 * 10 ^ -5",
+            format!("{:?}", tifloat!(0x50000000000000 * 10 ^ -5))
+        );
+    }
+
+    #[test]
+    fn sig_figs() {
+        assert_eq!(
+            vec![1, 2, 3],
+            tifloat!(0x12300000000000 * 10 ^ -1).significant_figures()
+        );
+        assert_eq!(
+            vec![0],
+            tifloat!(0x00000000000000 * 10 ^ 0).significant_figures()
+        );
     }
 }
diff --git a/src/mantissa.rs b/src/mantissa.rs
index d32200d..4818162 100644
--- a/src/mantissa.rs
+++ b/src/mantissa.rs
@@ -132,6 +132,7 @@ impl Sub for Mantissa {
     }
 }
 
+/// # Core operations
 impl Mantissa {
     /// Returns the unnormalized sum and the overflow flag.
     pub fn overflowing_add(self, rhs: Self) -> (Self, bool) {
@@ -214,6 +215,18 @@ impl Mantissa {
     }
 }
 
+impl Mantissa {
+    pub fn digits(&self) -> Vec<u8> {
+        let mut nibbles = Vec::with_capacity(16);
+        for i in (0..14).rev() {
+            let nibble = (self.data >> 4*i) & 0x0F;
+            nibbles.push(nibble as u8);
+        }
+
+        nibbles
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -340,4 +353,15 @@ mod tests {
             )
         );
     }
+
+    #[test]
+    fn digits() {
+        assert_eq!(
+            Mantissa {
+                data: 0x0014285714285714
+            }
+            .digits(),
+            vec![1, 4, 2, 8, 5, 7, 1, 4, 2, 8, 5, 7, 1, 4]
+        )
+    }
 }