Merge pull request #1182 from CryZe/chunk-64bit

Ensure the SWAR chunks are 64-bit in more cases

Author: dtolnay

src/read.rs

@@ -445,7 +445,22 @@ impl<'a> SliceRead<'a> {
  // than a naive loop. It runs faster than equivalent two-pass memchr2+SWAR code on
  // benchmarks and it's cross-platform, so probably the right fit.
  // [1]: https://groups.google.com/forum/#!original/comp.lang.c/2HtQXvg7iKc/xOJeipH6KLMJ
+
+ // The following architectures have native support for 64-bit integers,
+ // but have targets where usize is not 64-bit.
+ #[cfg(any(
+ target_arch = "aarch64",
+ target_arch = "x86_64",
+ target_arch = "wasm32",
+ ))]
+ type Chunk = u64;
+ #[cfg(not(any(
+ target_arch = "aarch64",
+ target_arch = "x86_64",
+ target_arch = "wasm32",
+ )))]
  type Chunk = usize;
+
  const STEP: usize = mem::size_of::<Chunk>();
  const ONE_BYTES: Chunk = Chunk::MAX / 255; // 0x0101...01