members/libpt-bintols/src/lib.rs

@@ -25,3 +25,4 @@ pub const YOBI: u128 = 2u128.pow(80);
 // use libpt_core;
 pub mod datalayout;
 pub mod display;
+pub mod split_numbers;

members/libpt-bintols/src/split_numbers.rs

@@ -0,0 +1,38 @@
+//! # Split numbers into bits and bytes
+//!
+//! Sometimes, you need a large integer in the form of many bytes, so split into [u8].
+//! Rust provides
+
+/// Split unsigned integers into a [Vec] of [u8]s
+///
+/// Say you have the [u32] 1717 (binary: `00000000 00000000 00000110 10110101 `). This number would
+/// be splitted to `vec![0b00000110, 0b10110101]`.
+///
+/// The 0 bytes of the numbers will be discarded (unless the number is 0, then the Vec contains a
+/// single Null byte.) and the remaining parts of the numbers are inserted into a Vec as [u8].
+///
+/// # Examples
+///
+/// ```
+/// # use libpt_bintols::split_numbers::*;
+///
+/// let x: u32 = 1717;
+///
+/// assert_eq!(unsigned_to_vec(x), vec![0b00000110, 0b10110101]);
+/// ```
+pub fn unsigned_to_vec<T>(num: T) -> Vec<u8>
+where
+    u128: std::convert::From<T>,
+{
+    let mut num: u128 = num.into();
+    if num == 0 {
+        return vec![0];
+    }
+    let mut buf: Vec<u8> = Vec::new();
+    while num > 0 {
+        buf.push(num as u8);
+        num >>= 8;
+    }
+    buf.reverse();
+    buf
+}

members/libpt-bintols/tests/split_numbers.rs

@@ -0,0 +1,55 @@
+use libpt_bintols::split_numbers::*;
+
+#[test]
+fn split_u128() {
+    let source = [
+        16,
+        255,
+        256,
+        0,
+        u128::MAX,
+        u64::MAX as u128,
+        u64::MAX as u128 + 1,
+    ];
+    let correct = [
+        vec![16],
+        vec![255],
+        vec![1, 0],
+        vec![0],
+        vec![
+            255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+        ],
+        vec![255, 255, 255, 255, 255, 255, 255, 255],
+        vec![1, 0, 0, 0, 0, 0, 0, 0, 0],
+    ];
+    for (i, n) in source.iter().enumerate() {
+        assert_eq!(unsigned_to_vec(*n), correct[i]);
+    }
+}
+
+#[test]
+fn split_u64() {
+    let source = [
+        16,
+        255,
+        256,
+        0,
+        u64::MAX,
+        u32::MAX as u64,
+        0b1_00000001,
+        0b10011011_10110101_11110000_00110011,
+    ];
+    let correct = [
+        vec![16],
+        vec![255],
+        vec![1, 0],
+        vec![0],
+        vec![255, 255, 255, 255, 255, 255, 255, 255],
+        vec![255, 255, 255, 255],
+        vec![1, 1],
+        vec![0b10011011, 0b10110101, 0b11110000, 0b00110011],
+    ];
+    for (i, n) in source.iter().enumerate() {
+        assert_eq!(unsigned_to_vec(*n), correct[i]);
+    }
+}