1 files changed, 217 insertions, 0 deletions
diff --git a/vendor/simd-adler32/src/imp/wasm.rs b/vendor/simd-adler32/src/imp/wasm.rs
new file mode 100644
index 0000000..5a9152b
--- /dev/null
+++ b/vendor/simd-adler32/src/imp/wasm.rs
@@ -0,0 +1,217 @@
+use super::Adler32Imp;
+
+/// Resolves update implementation if CPU supports simd128 instructions.
+pub fn get_imp() -> Option<Adler32Imp> {
+  get_imp_inner()
+}
+
+#[inline]
+#[cfg(target_feature = "simd128")]
+fn get_imp_inner() -> Option<Adler32Imp> {
+  Some(imp::update)
+}
+
+#[inline]
+#[cfg(not(target_feature = "simd128"))]
+fn get_imp_inner() -> Option<Adler32Imp> {
+  None
+}
+
+#[cfg(target_feature = "simd128")]
+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 = "wasm32")]
+  use core::arch::wasm32::*;
+  #[cfg(target_arch = "wasm64")]
+  use core::arch::wasm64::*;
+
+  pub fn update(a: u16, b: u16, data: &[u8]) -> (u16, u16) {
+    update_imp(a, b, data)
+  }
+
+  #[inline]
+  #[target_feature(enable = "simd128")]
+  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)
+  }
+
+  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;
+  }
+
+  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)]
+  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 weight_hi_v = get_weight_hi();
+    let weight_lo_v = get_weight_lo();
+
+    let mut p_v = u32x4(*a * blocks.len() as u32, 0, 0, 0);
+    let mut a_v = u32x4(0, 0, 0, 0);
+    let mut b_v = u32x4(*b, 0, 0, 0);
+
+    for block in blocks {
+      let block_ptr = block.as_ptr() as *const v128;
+      let v_lo = unsafe { block_ptr.read_unaligned() };
+      let v_hi = unsafe { block_ptr.add(1).read_unaligned() };
+
+      p_v = u32x4_add(p_v, a_v);
+
+      a_v = u32x4_add(a_v, u32x4_extadd_quarters_u8x16(v_lo));
+      let mad = i32x4_dot_i8x16(v_lo, weight_lo_v);
+      b_v = u32x4_add(b_v, mad);
+
+      a_v = u32x4_add(a_v, u32x4_extadd_quarters_u8x16(v_hi));
+      let mad = i32x4_dot_i8x16(v_hi, weight_hi_v);
+      b_v = u32x4_add(b_v, mad);
+    }
+
+    b_v = u32x4_add(b_v, u32x4_shl(p_v, 5));
+
+    *a += reduce_add(a_v);
+    *b = reduce_add(b_v);
+
+    blocks_remainder
+  }
+
+  #[inline(always)]
+  fn i32x4_dot_i8x16(a: v128, b: v128) -> v128 {
+    let a_lo = u16x8_extend_low_u8x16(a);
+    let a_hi = u16x8_extend_high_u8x16(a);
+
+    let b_lo = u16x8_extend_low_u8x16(b);
+    let b_hi = u16x8_extend_high_u8x16(b);
+
+    let lo = i32x4_dot_i16x8(a_lo, b_lo);
+    let hi = i32x4_dot_i16x8(a_hi, b_hi);
+
+    i32x4_add(lo, hi)
+  }
+
+  #[inline(always)]
+  fn u32x4_extadd_quarters_u8x16(a: v128) -> v128 {
+    u32x4_extadd_pairwise_u16x8(u16x8_extadd_pairwise_u8x16(a))
+  }
+
+  #[inline(always)]
+  fn reduce_add(v: v128) -> u32 {
+    let arr: [u32; 4] = unsafe { std::mem::transmute(v) };
+    let mut sum = 0u32;
+    for val in arr {
+      sum = sum.wrapping_add(val);
+    }
+    sum
+  }
+
+  #[inline(always)]
+  fn get_weight_lo() -> v128 {
+    u8x16(
+      32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17,
+    )
+  }
+
+  #[inline(always)]
+  fn get_weight_hi() -> v128 {
+    u8x16(16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1)
+  }
+}
+
+#[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; 512 * 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; 512 * 1024]);
+  }
+
+  #[test]
+  fn random() {
+    let mut random = [0; 512 * 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[..512 * 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());
+    }
+  }
+}