Add v3-preview module gathering a few breaking changes

This new module addresses the following breaking changes of #72: - `static` instead of `const` for pre-defined encodings - Private `Encoding` implementation with `unsafe` constructor - Use `MaybeUninit` internally and expose `_uninit` functions - Use static dispatch instead of dynamic dispatch (fixing #97)
ia0 · Apr 28, 2024 · 88341ba · 88341ba
1 parent 18203b9
commit 88341ba
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Showing 5 changed files with 1,186 additions and 7 deletions.
diff --git a/lib/Cargo.toml b/lib/Cargo.toml
@@ -21,3 +21,4 @@ rustdoc-args = ["--cfg=docsrs"]
 default = ["std"]
 alloc = []
 std = ["alloc"]
+v3-preview = []
diff --git a/lib/fuzz/Cargo.toml b/lib/fuzz/Cargo.toml
@@ -29,3 +29,10 @@ name = "encode_write"
 path = "fuzz_targets/encode_write.rs"
 test = false
 doc = false
+
+[[bin]]
+name = "v3-preview"
+path = "fuzz_targets/v3-preview.rs"
+test = false
+doc = false
+required-features = ["data-encoding/v3-preview"]
diff --git a/lib/fuzz/fuzz_targets/v3-preview.rs b/lib/fuzz/fuzz_targets/v3-preview.rs
@@ -0,0 +1,98 @@
+#![no_main]
+
+use data_encoding::v3_preview::{Bit1, Bit2, Bit3, Bit4, Bit5, Bit6, Encoding, False, True};
+use data_encoding_fuzz::{decode_prefix, generate_encoding};
+use libfuzzer_sys::fuzz_target;
+
+fuzz_target!(|data: &[u8]| {
+    let mut data = data;
+    let dyn_base = generate_encoding(&mut data);
+    let mut count = 0;
+    macro_rules! test {
+        ($Bit:ident, $Msb:ident, $Pad:ident, $Wrap:ident, $Ignore:ident) => {
+            if let Ok(base) = <&Encoding<$Bit, $Msb, $Pad, $Wrap, $Ignore>>::try_from(&dyn_base) {
+                count += 1;
+                let encoded = base.encode(data);
+                assert_eq!(encoded, dyn_base.encode(data));
+                assert_eq!(base.decode(encoded.as_bytes()).unwrap(), data);
+                if dyn_base.is_canonical() {
+                    let raw = decode_prefix(&dyn_base, &mut data);
+                    assert_eq!(base.encode(&raw).as_bytes(), data);
+                }
+            }
+        };
+    }
+    test!(Bit1, False, False, False, False);
+    test!(Bit1, False, False, False, True);
+    test!(Bit1, False, False, True, True);
+    test!(Bit1, False, True, False, False);
+    test!(Bit1, False, True, False, True);
+    test!(Bit1, False, True, True, True);
+    test!(Bit1, True, False, False, False);
+    test!(Bit1, True, False, False, True);
+    test!(Bit1, True, False, True, True);
+    test!(Bit1, True, True, False, False);
+    test!(Bit1, True, True, False, True);
+    test!(Bit1, True, True, True, True);
+    test!(Bit2, False, False, False, False);
+    test!(Bit2, False, False, False, True);
+    test!(Bit2, False, False, True, True);
+    test!(Bit2, False, True, False, False);
+    test!(Bit2, False, True, False, True);
+    test!(Bit2, False, True, True, True);
+    test!(Bit2, True, False, False, False);
+    test!(Bit2, True, False, False, True);
+    test!(Bit2, True, False, True, True);
+    test!(Bit2, True, True, False, False);
+    test!(Bit2, True, True, False, True);
+    test!(Bit2, True, True, True, True);
+    test!(Bit3, False, False, False, False);
+    test!(Bit3, False, False, False, True);
+    test!(Bit3, False, False, True, True);
+    test!(Bit3, False, True, False, False);
+    test!(Bit3, False, True, False, True);
+    test!(Bit3, False, True, True, True);
+    test!(Bit3, True, False, False, False);
+    test!(Bit3, True, False, False, True);
+    test!(Bit3, True, False, True, True);
+    test!(Bit3, True, True, False, False);
+    test!(Bit3, True, True, False, True);
+    test!(Bit3, True, True, True, True);
+    test!(Bit4, False, False, False, False);
+    test!(Bit4, False, False, False, True);
+    test!(Bit4, False, False, True, True);
+    test!(Bit4, False, True, False, False);
+    test!(Bit4, False, True, False, True);
+    test!(Bit4, False, True, True, True);
+    test!(Bit4, True, False, False, False);
+    test!(Bit4, True, False, False, True);
+    test!(Bit4, True, False, True, True);
+    test!(Bit4, True, True, False, False);
+    test!(Bit4, True, True, False, True);
+    test!(Bit4, True, True, True, True);
+    test!(Bit5, False, False, False, False);
+    test!(Bit5, False, False, False, True);
+    test!(Bit5, False, False, True, True);
+    test!(Bit5, False, True, False, False);
+    test!(Bit5, False, True, False, True);
+    test!(Bit5, False, True, True, True);
+    test!(Bit5, True, False, False, False);
+    test!(Bit5, True, False, False, True);
+    test!(Bit5, True, False, True, True);
+    test!(Bit5, True, True, False, False);
+    test!(Bit5, True, True, False, True);
+    test!(Bit5, True, True, True, True);
+    test!(Bit6, False, False, False, False);
+    test!(Bit6, False, False, False, True);
+    test!(Bit6, False, False, True, True);
+    test!(Bit6, False, True, False, False);
+    test!(Bit6, False, True, False, True);
+    test!(Bit6, False, True, True, True);
+    test!(Bit6, True, False, False, False);
+    test!(Bit6, True, False, False, True);
+    test!(Bit6, True, False, True, True);
+    test!(Bit6, True, True, False, False);
+    test!(Bit6, True, True, False, True);
+    test!(Bit6, True, True, True, True);
+    assert_eq!(count, 1);
+});
diff --git a/lib/src/lib.rs b/lib/src/lib.rs
@@ -184,6 +184,9 @@ macro_rules! check {
     };
 }
 
+#[cfg(feature = "v3-preview")]
+pub mod v3_preview;
+
 trait Static<T: Copy>: Copy {
     fn val(self) -> T;
 }
@@ -255,21 +258,21 @@ macro_rules! dispatch {
     ($body: expr) => { $body };
 }
 
-unsafe fn chunk_unchecked(x: &[u8], n: usize, i: usize) -> &[u8] {
+unsafe fn chunk_unchecked<T>(x: &[T], n: usize, i: usize) -> &[T] {
     debug_assert!((i + 1) * n <= x.len());
     unsafe { core::slice::from_raw_parts(x.as_ptr().add(n * i), n) }
 }
 
-unsafe fn chunk_mut_unchecked(x: &mut [u8], n: usize, i: usize) -> &mut [u8] {
+unsafe fn chunk_mut_unchecked<T>(x: &mut [T], n: usize, i: usize) -> &mut [T] {
     debug_assert!((i + 1) * n <= x.len());
     unsafe { core::slice::from_raw_parts_mut(x.as_mut_ptr().add(n * i), n) }
 }
 
-fn div_ceil(x: usize, m: usize) -> usize {
+const fn div_ceil(x: usize, m: usize) -> usize {
     (x + m - 1) / m
 }
 
-fn floor(x: usize, m: usize) -> usize {
+const fn floor(x: usize, m: usize) -> usize {
     x / m * m
 }
 
@@ -354,15 +357,15 @@ const INVALID: u8 = 128;
 const IGNORE: u8 = 129;
 const PADDING: u8 = 130;
 
-fn order(msb: bool, n: usize, i: usize) -> usize {
+const fn order(msb: bool, n: usize, i: usize) -> usize {
     if msb {
         n - 1 - i
     } else {
         i
     }
 }
 
-fn enc(bit: usize) -> usize {
+const fn enc(bit: usize) -> usize {
     match bit {
         1 | 2 | 4 => 1,
         3 | 6 => 3,
@@ -371,7 +374,7 @@ fn enc(bit: usize) -> usize {
     }
 }
 
-fn dec(bit: usize) -> usize {
+const fn dec(bit: usize) -> usize {
     enc(bit) * 8 / bit
 }
 
@@ -880,6 +883,7 @@ pub type InternalEncoding = &'static [u8];
 // - width % dec(bit) == 0
 // - for all x in separator values[x] is IGNORE
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[repr(transparent)]
 pub struct Encoding(#[doc(hidden)] pub InternalEncoding);
 
 /// How to translate characters when decoding