0.2.10 version

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "const_panic"
-version = "0.2.9"
+version = "0.2.10"
 authors = ["rodrimati1992 <[email protected]>"]
 edition = "2021"
 license = "Zlib"

Changelog.md

@@ -2,6 +2,13 @@ This changelog is a summary of the changes made in each release.
 
 # 0.2
 
+### 0.2.10
+
+[Fixed internal use of the panic macro to not append nul bytes to the output](<https://github.com/rodrimati1992/const_panic/pull/12>).
+
+Added `const_panic::utils::bytes_up_to` function.
+
+
 ### 0.2.7
 
 Added `concat_` macro, which requires `"non_basic"` feature.

src/fmt/char_formatting.rs

@@ -50,7 +50,7 @@ const fn hex_as_ascii(n: u8) -> u8 {
     }
 }
 
-#[cfg(any(test, feature = "fmt"))]
+#[cfg(test)]
 pub(crate) const fn char_debug_len(c: char) -> usize {
     let inner = match c {
         '\t' | '\r' | '\n' | '\\' | '\'' => 2,

src/lib.rs

@@ -225,11 +225,6 @@ mod panic_val;
 #[cfg(feature = "non_basic")]
 mod const_default;
 
-#[cfg(not(feature = "non_basic"))]
-mod utils;
-
-#[cfg(feature = "non_basic")]
-#[cfg_attr(feature = "docsrs", doc(cfg(feature = "non_basic")))]
 pub mod utils;
 
 #[cfg(all(test, not(feature = "test")))]

src/utils.rs

@@ -9,6 +9,7 @@ mod utils_1_64_tests;
 mod non_basic_utils;
 
 #[cfg(feature = "non_basic")]
+#[cfg_attr(feature = "docsrs", doc(cfg(feature = "non_basic")))]
 pub use self::non_basic_utils::*;
 
 pub(crate) const fn min_usize(l: usize, r: usize) -> usize {
@@ -231,32 +232,55 @@ pub(crate) const fn tail_byte_array<const TO: usize>(
 
 ////////////////////////////////////////////////////////////////////////////////
 
-#[cfg(not(feature = "rust_1_64"))]
-pub const fn bytes_up_to(buffer: &[u8], upto: usize) -> &[u8] {
-    let mut to_truncate = buffer.len() - upto;
-    let mut out: &[u8] = buffer;
 
-    while to_truncate != 0 {
-        if let [rem @ .., _] = out {
-            out = rem;
-        }
-        to_truncate -= 1;
+/// Const equivalent of `&buffer[..upto]` with saturating indexing.
+/// 
+/// "saturating indexing" means that if `upto > buffer.len()`, 
+/// then this returns all of `buffer` instead of panicking.
+/// 
+/// # Example 
+/// 
+/// ```rust
+/// use const_panic::utils::bytes_up_to;
+/// 
+/// const BYTES: &[u8] = &[3, 5, 8, 13, 21, 34, 55, 89];
+/// 
+/// const SLICE: &[u8] = bytes_up_to(BYTES, 4);
+/// assert_eq!(SLICE, &[3, 5, 8, 13][..]);
+/// 
+/// const WHOLE: &[u8] = bytes_up_to(BYTES, usize::MAX);
+/// assert_eq!(WHOLE, &[3, 5, 8, 13, 21, 34, 55, 89][..]);
+/// 
+/// ```
+pub const fn bytes_up_to(buffer: &[u8], upto: usize) -> &[u8] {
+    if upto > buffer.len() {
+        return buffer;
     }
 
-    if out.len() != upto {
-        panic!("BUG!")
-    }
+    #[cfg(not(feature = "rust_1_64"))]
+    {
+        let mut to_truncate = buffer.len() - upto;
+        let mut out: &[u8] = buffer;
 
-    out
-}
+        while to_truncate != 0 {
+            if let [rem @ .., _] = out {
+                out = rem;
+            }
+            to_truncate -= 1;
+        }
 
-#[cfg(feature = "rust_1_64")]
-pub const fn bytes_up_to(buffer: &[u8], upto: usize) -> &[u8] {
-    if upto > buffer.len() {
-        return buffer;
+        if out.len() != upto {
+            panic!("BUG!")
+        }
+
+        out
     }
 
-    // SAFETY: the above conditional ensures that `upto` doesn't
-    // create a partially-dangling slice
-    unsafe { core::slice::from_raw_parts(buffer.as_ptr(), upto) }
+    #[cfg(feature = "rust_1_64")]
+    {
+        // SAFETY: the above conditional ensures that `upto` doesn't
+        // create a partially-dangling slice
+        unsafe { core::slice::from_raw_parts(buffer.as_ptr(), upto) }
+    }
 }
+

tests/main_test_modules.rs

@@ -44,4 +44,6 @@ mod main_tests {
     mod pvcount_tests;
 
     mod string_tests;
+
+    mod utils_tests;
 }

tests/main_tests/utils_tests.rs

@@ -0,0 +1,34 @@
+use const_panic::utils::bytes_up_to;
+
+
+macro_rules! case {
+    ($bytes:expr, $upto:expr) => ({
+        const SLICE: &[u8] = bytes_up_to($bytes, $upto);
+        assert_eq!(slice, );
+    })
+}
+
+
+#[test]
+fn test_bytes_up_to_isconst() {
+    const SLICE: &[u8] = bytes_up_to(&[10, 20], 1);
+
+    assert_eq!(SLICE, &[10][..]);
+}
+
+#[test]
+fn test_bytes_up_to() {
+    const BYTES: &[u8] = &[3, 5, 8, 13, 21, 34];
+
+    let iter = (0..=BYTES.len() + 2).chain([usize::MAX - 1, usize::MAX]);
+
+    for bytes_len in iter.clone() {
+        let bytes = BYTES.get(..bytes_len).unwrap_or(BYTES);
+        for upto in iter.clone() {
+            assert_eq!(
+                bytes_up_to(bytes, upto),
+                bytes.get(..upto).unwrap_or(bytes),
+            )
+        }
+    }
+}