1 files changed, 214 insertions, 0 deletions
diff --git a/vendor/simd-adler32/src/imp/avx2.rs b/vendor/simd-adler32/src/imp/avx2.rs
new file mode 100644
index 0000000..c16cc99
--- /dev/null
+++ b/vendor/simd-adler32/src/imp/avx2.rs
@@ -0,0 +1,214 @@
+use super::Adler32Imp;
+
+/// Resolves update implementation if CPU supports avx2 instructions.
+pub fn get_imp() -> Option<Adler32Imp> {
+  get_imp_inner()
+}
+
+#[inline]
+#[cfg(all(feature = "std", any(target_arch = "x86", target_arch = "x86_64")))]
+fn get_imp_inner() -> Option<Adler32Imp> {
+  if std::is_x86_feature_detected!("avx2") {
+    Some(imp::update)
+  } else {
+    None
+  }
+}
+
+#[inline]
+#[cfg(all(
+  target_feature = "avx2",
+  not(all(feature = "std", any(target_arch = "x86", target_arch = "x86_64")))
+))]
+fn get_imp_inner() -> Option<Adler32Imp> {
+  Some(imp::update)
+}
+
+#[inline]
+#[cfg(all(
+  not(target_feature = "avx2"),
+  not(all(feature = "std", any(target_arch = "x86", target_arch = "x86_64")))
+))]
+fn get_imp_inner() -> Option<Adler32Imp> {
+  None
+}
+
+#[cfg(all(
+  any(target_arch = "x86", target_arch = "x86_64"),
+  any(feature = "std", target_feature = "avx2")
+))]
+mod imp {
+  const MOD: u32 = 65521;
+  const NMAX: usize = 5552;
+  const BLOCK_SIZE: usize = 32;
+  const CHUNK_SIZE: usize = NMAX / BLOCK_SIZE * BLOCK_SIZE;
+
+  #[cfg(target_arch = "x86")]
+  use core::arch::x86::*;
+  #[cfg(target_arch = "x86_64")]
+  use core::arch::x86_64::*;
+
+  pub fn update(a: u16, b: u16, data: &[u8]) -> (u16, u16) {
+    unsafe { update_imp(a, b, data) }
+  }
+
+  #[inline]
+  #[target_feature(enable = "avx2")]
+  unsafe fn update_imp(a: u16, b: u16, data: &[u8]) -> (u16, u16) {
+    let mut a = a as u32;
+    let mut b = b as u32;
+
+    let chunks = data.chunks_exact(CHUNK_SIZE);
+    let remainder = chunks.remainder();
+    for chunk in chunks {
+      update_chunk_block(&mut a, &mut b, chunk);
+    }
+
+    update_block(&mut a, &mut b, remainder);
+
+    (a as u16, b as u16)
+  }
+
+  #[inline]
+  unsafe fn update_chunk_block(a: &mut u32, b: &mut u32, chunk: &[u8]) {
+    debug_assert_eq!(
+      chunk.len(),
+      CHUNK_SIZE,
+      "Unexpected chunk size (expected {}, got {})",
+      CHUNK_SIZE,
+      chunk.len()
+    );
+
+    reduce_add_blocks(a, b, chunk);
+
+    *a %= MOD;
+    *b %= MOD;
+  }
+
+  #[inline]
+  unsafe fn update_block(a: &mut u32, b: &mut u32, chunk: &[u8]) {
+    debug_assert!(
+      chunk.len() <= CHUNK_SIZE,
+      "Unexpected chunk size (expected <= {}, got {})",
+      CHUNK_SIZE,
+      chunk.len()
+    );
+
+    for byte in reduce_add_blocks(a, b, chunk) {
+      *a += *byte as u32;
+      *b += *a;
+    }
+
+    *a %= MOD;
+    *b %= MOD;
+  }
+
+  #[inline(always)]
+  unsafe fn reduce_add_blocks<'a>(a: &mut u32, b: &mut u32, chunk: &'a [u8]) -> &'a [u8] {
+    if chunk.len() < BLOCK_SIZE {
+      return chunk;
+    }
+
+    let blocks = chunk.chunks_exact(BLOCK_SIZE);
+    let blocks_remainder = blocks.remainder();
+
+    let one_v = _mm256_set1_epi16(1);
+    let zero_v = _mm256_setzero_si256();
+    let weights = get_weights();
+
+    let mut p_v = _mm256_set_epi32(0, 0, 0, 0, 0, 0, 0, (*a * blocks.len() as u32) as _);
+    let mut a_v = _mm256_setzero_si256();
+    let mut b_v = _mm256_set_epi32(0, 0, 0, 0, 0, 0, 0, *b as _);
+
+    for block in blocks {
+      let block_ptr = block.as_ptr() as *const _;
+      let block = _mm256_loadu_si256(block_ptr);
+
+      p_v = _mm256_add_epi32(p_v, a_v);
+
+      a_v = _mm256_add_epi32(a_v, _mm256_sad_epu8(block, zero_v));
+      let mad = _mm256_maddubs_epi16(block, weights);
+      b_v = _mm256_add_epi32(b_v, _mm256_madd_epi16(mad, one_v));
+    }
+
+    b_v = _mm256_add_epi32(b_v, _mm256_slli_epi32(p_v, 5));
+
+    *a += reduce_add(a_v);
+    *b = reduce_add(b_v);
+
+    blocks_remainder
+  }
+
+  #[inline(always)]
+  unsafe fn reduce_add(v: __m256i) -> u32 {
+    let sum = _mm_add_epi32(_mm256_castsi256_si128(v), _mm256_extracti128_si256(v, 1));
+    let hi = _mm_unpackhi_epi64(sum, sum);
+
+    let sum = _mm_add_epi32(hi, sum);
+    let hi = _mm_shuffle_epi32(sum, crate::imp::_MM_SHUFFLE(2, 3, 0, 1));
+
+    let sum = _mm_add_epi32(sum, hi);
+
+    _mm_cvtsi128_si32(sum) as _
+  }
+
+  #[inline(always)]
+  unsafe fn get_weights() -> __m256i {
+    _mm256_set_epi8(
+      1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
+      24, 25, 26, 27, 28, 29, 30, 31, 32,
+    )
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use rand::Rng;
+
+  #[test]
+  fn zeroes() {
+    assert_sum_eq(&[]);
+    assert_sum_eq(&[0]);
+    assert_sum_eq(&[0, 0]);
+    assert_sum_eq(&[0; 100]);
+    assert_sum_eq(&[0; 1024]);
+    assert_sum_eq(&[0; 1024 * 1024]);
+  }
+
+  #[test]
+  fn ones() {
+    assert_sum_eq(&[]);
+    assert_sum_eq(&[1]);
+    assert_sum_eq(&[1, 1]);
+    assert_sum_eq(&[1; 100]);
+    assert_sum_eq(&[1; 1024]);
+    assert_sum_eq(&[1; 1024 * 1024]);
+  }
+
+  #[test]
+  fn random() {
+    let mut random = [0; 1024 * 1024];
+    rand::thread_rng().fill(&mut random[..]);
+
+    assert_sum_eq(&random[..1]);
+    assert_sum_eq(&random[..100]);
+    assert_sum_eq(&random[..1024]);
+    assert_sum_eq(&random[..1024 * 1024]);
+  }
+
+  /// Example calculation from https://en.wikipedia.org/wiki/Adler-32.
+  #[test]
+  fn wiki() {
+    assert_sum_eq(b"Wikipedia");
+  }
+
+  fn assert_sum_eq(data: &[u8]) {
+    if let Some(update) = super::get_imp() {
+      let (a, b) = update(1, 0, data);
+      let left = u32::from(b) << 16 | u32::from(a);
+      let right = adler::adler32_slice(data);
+
+      assert_eq!(left, right, "len({})", data.len());
+    }
+  }
+}