chore: add vendor directory

1 files changed, 258 insertions, 0 deletions

diff --git a/vendor/httparse/src/simd/neon.rs b/vendor/httparse/src/simd/neon.rs
new file mode 100644
index 00000000..b059efb2
--- /dev/null
+++ b/vendor/httparse/src/simd/neon.rs
@@ -0,0 +1,258 @@
+use crate::iter::Bytes;
+use core::arch::aarch64::*;
+
+#[inline]
+pub fn match_header_name_vectored(bytes: &mut Bytes) {
+    while bytes.as_ref().len() >= 16 {
+        // SAFETY: ensured that there are at least 16 bytes remaining 
+        unsafe {
+            let advance = match_header_name_char_16_neon(bytes.as_ref().as_ptr());
+            bytes.advance(advance);
+
+            if advance != 16 {
+                return;
+            }
+        }
+    }
+    super::swar::match_header_name_vectored(bytes);
+}
+
+#[inline]
+pub fn match_header_value_vectored(bytes: &mut Bytes) {
+    while bytes.as_ref().len() >= 16 {
+        // SAFETY: ensured that there are at least 16 bytes remaining 
+        unsafe {
+            let advance = match_header_value_char_16_neon(bytes.as_ref().as_ptr());
+            bytes.advance(advance);
+
+            if advance != 16 {
+                return;
+            }
+        }
+    }
+    super::swar::match_header_value_vectored(bytes);
+}
+
+#[inline]
+pub fn match_uri_vectored(bytes: &mut Bytes) {
+    while bytes.as_ref().len() >= 16 {
+        // SAFETY: ensured that there are at least 16 bytes remaining 
+        unsafe {
+            let advance = match_url_char_16_neon(bytes.as_ref().as_ptr());
+            bytes.advance(advance);
+
+            if advance != 16 {
+                return;
+            }
+        }
+    }
+    super::swar::match_uri_vectored(bytes);
+}
+
+const fn bit_set(x: u8) -> bool {
+    // Validates if a byte is a valid header name character
+    // https://tools.ietf.org/html/rfc7230#section-3.2.6
+    matches!(x, b'0'..=b'9' | b'a'..=b'z' | b'A'..=b'Z' | b'!' | b'#' | b'$' | b'%' | b'&' | b'\'' | b'*' | b'+' | b'-' | b'.' | b'^' | b'_' | b'`' | b'|' | b'~')
+}
+
+// A 256-bit bitmap, split into two halves
+// lower half contains bits whose higher nibble is <= 7
+// higher half contains bits whose higher nibble is >= 8
+const fn build_bitmap() -> ([u8; 16], [u8; 16]) {
+    let mut bitmap_0_7 = [0u8; 16]; // 0x00..0x7F
+    let mut bitmap_8_15 = [0u8; 16]; // 0x80..0xFF
+    let mut i = 0;
+    while i < 256 {
+        if bit_set(i as u8) {
+            // Nibbles
+            let (lo, hi) = (i & 0x0F, i >> 4);
+            if i < 128 {
+                bitmap_0_7[lo] |= 1 << hi;
+            } else {
+                bitmap_8_15[lo] |= 1 << hi;
+            }
+        }
+        i += 1;
+    }
+    (bitmap_0_7, bitmap_8_15)
+}
+
+const BITMAPS: ([u8; 16], [u8; 16]) = build_bitmap();
+
+// NOTE: adapted from 256-bit version, with upper 128-bit ops commented out
+#[inline]
+unsafe fn match_header_name_char_16_neon(ptr: *const u8) -> usize {
+    let bitmaps = BITMAPS;
+    // NOTE: ideally compile-time constants
+    let (bitmap_0_7, _bitmap_8_15) = bitmaps;
+    let bitmap_0_7 = vld1q_u8(bitmap_0_7.as_ptr());
+    // let bitmap_8_15 = vld1q_u8(bitmap_8_15.as_ptr());
+
+    // Initialize the bitmask_lookup.
+    const BITMASK_LOOKUP_DATA: [u8; 16] =
+        [1, 2, 4, 8, 16, 32, 64, 128, 1, 2, 4, 8, 16, 32, 64, 128];
+    let bitmask_lookup = vld1q_u8(BITMASK_LOOKUP_DATA.as_ptr());
+
+    // Load 16 input bytes.
+    let input = vld1q_u8(ptr);
+
+    // Extract indices for row_0_7.
+    let indices_0_7 = vandq_u8(input, vdupq_n_u8(0x8F)); // 0b1000_1111;
+
+    // Extract indices for row_8_15.
+    // let msb = vandq_u8(input, vdupq_n_u8(0x80));
+    // let indices_8_15 = veorq_u8(indices_0_7, msb);
+
+    // Fetch row_0_7 and row_8_15.
+    let row_0_7 = vqtbl1q_u8(bitmap_0_7, indices_0_7);
+    // let row_8_15 = vqtbl1q_u8(bitmap_8_15, indices_8_15);
+
+    // Calculate a bitmask, i.e. (1 << hi_nibble % 8).
+    let bitmask = vqtbl1q_u8(bitmask_lookup, vshrq_n_u8(input, 4));
+
+    // Choose rows halves depending on higher nibbles.
+    // let bitsets = vorrq_u8(row_0_7, row_8_15);
+    let bitsets = row_0_7;
+
+    // Finally check which bytes belong to the set.
+    let tmp = vandq_u8(bitsets, bitmask);
+    let result = vceqq_u8(tmp, bitmask);
+
+    offsetz(result) as usize
+}
+
+#[inline]
+unsafe fn match_url_char_16_neon(ptr: *const u8) -> usize {
+    let input = vld1q_u8(ptr);
+
+    // Check that b'!' <= and b != 127
+    let result = vcleq_u8(vdupq_n_u8(b'!'), input);
+
+    // Disallow del
+    let del = vceqq_u8(input, vdupq_n_u8(0x7F));
+    let result = vbicq_u8(result, del);
+
+    offsetz(result) as usize
+}
+
+#[inline]
+unsafe fn match_header_value_char_16_neon(ptr: *const u8) -> usize {
+    let input = vld1q_u8(ptr);
+
+    // Check that b' ' <= and b != 127 or b == 9
+    let result = vcleq_u8(vdupq_n_u8(b' '), input);
+
+    // Allow tab
+    let tab = vceqq_u8(input, vdupq_n_u8(0x09));
+    let result = vorrq_u8(result, tab);
+
+    // Disallow del
+    let del = vceqq_u8(input, vdupq_n_u8(0x7F));
+    let result = vbicq_u8(result, del);
+
+    offsetz(result) as usize
+}
+
+#[inline]
+unsafe fn offsetz(x: uint8x16_t) -> u32 {
+    // NOT the vector since it's faster to operate with zeros instead
+    offsetnz(vmvnq_u8(x))
+}
+
+#[inline]
+unsafe fn offsetnz(x: uint8x16_t) -> u32 {
+    // Extract two u64
+    let x = vreinterpretq_u64_u8(x);
+    // Extract to general purpose registers to perform clz
+    let low: u64 = vgetq_lane_u64::<0>(x);
+    let high: u64 = vgetq_lane_u64::<1>(x);
+
+    #[inline]
+    fn clz(x: u64) -> u32 {
+        // perf: rust will unroll this loop
+        // and it's much faster than rbit + clz so voila
+        for (i, b) in x.to_ne_bytes().iter().copied().enumerate() {
+            if b != 0 {
+                return i as u32;
+            }
+        }
+        8 // Technically not reachable since zero-guarded
+    }
+
+    if low != 0 {
+        clz(low)
+    } else if high != 0 {
+        return 8 + clz(high);
+    } else {
+        return 16;
+    }
+}
+
+#[test]
+fn neon_code_matches_uri_chars_table() {
+    #[allow(clippy::undocumented_unsafe_blocks)]
+    unsafe {
+        assert!(byte_is_allowed(b'_', match_uri_vectored));
+
+        for (b, allowed) in crate::URI_MAP.iter().cloned().enumerate() {
+            assert_eq!(
+                byte_is_allowed(b as u8, match_uri_vectored),
+                allowed,
+                "byte_is_allowed({:?}) should be {:?}",
+                b,
+                allowed,
+            );
+        }
+    }
+}
+
+#[test]
+fn neon_code_matches_header_value_chars_table() {
+    #[allow(clippy::undocumented_unsafe_blocks)]
+    unsafe {
+        assert!(byte_is_allowed(b'_', match_header_value_vectored));
+
+        for (b, allowed) in crate::HEADER_VALUE_MAP.iter().cloned().enumerate() {
+            assert_eq!(
+                byte_is_allowed(b as u8, match_header_value_vectored),
+                allowed,
+                "byte_is_allowed({:?}) should be {:?}",
+                b,
+                allowed,
+            );
+        }
+    }
+}
+
+#[test]
+fn neon_code_matches_header_name_chars_table() {
+    #[allow(clippy::undocumented_unsafe_blocks)]
+    unsafe {
+        assert!(byte_is_allowed(b'_', match_header_name_vectored));
+
+        for (b, allowed) in crate::TOKEN_MAP.iter().cloned().enumerate() {
+            assert_eq!(
+                byte_is_allowed(b as u8, match_header_name_vectored),
+                allowed,
+                "byte_is_allowed({:?}) should be {:?}",
+                b,
+                allowed,
+            );
+        }
+    }
+}
+
+#[cfg(test)]
+unsafe fn byte_is_allowed(byte: u8, f: unsafe fn(bytes: &mut Bytes<'_>)) -> bool {
+    let mut slice = [b'_'; 16];
+    slice[10] = byte;
+    let mut bytes = Bytes::new(&slice);
+
+    f(&mut bytes);
+
+    match bytes.pos() {
+        16 => true,
+        10 => false,
+        x => panic!("unexpected pos: {}", x),
+    }
+}