Revert "simd: split cursor advancing from value matching (#156)"

This reverts commit b2625f3.

Author: seanmonstar

src/lib.rs

@@ -953,20 +953,18 @@ fn parse_token<'a>(bytes: &mut Bytes<'a>) -> Result<&'a str> {
 #[allow(missing_docs)]
 // WARNING: Exported for internal benchmarks, not fit for public consumption
 pub fn parse_uri<'a>(bytes: &mut Bytes<'a>) -> Result<&'a str> {
+    let start = bytes.pos();
+    simd::match_uri_vectored(bytes);
     // URI must have at least one char
-    let uri_len = simd::match_uri_vectored(bytes.as_ref());
-    if uri_len == 0 {
+    if bytes.pos() == start {
         return Err(Error::Token);
     }
-    // SAFETY: these bytes have just been matched here above.
-    unsafe { bytes.advance(uri_len) };
-    let uri_slice = bytes.slice();
 
-    let space_delim = next!(bytes);
-    if space_delim == b' ' {
-        // SAFETY: all bytes within `uri_slice` must have been `is_token` and therefore also utf-8.
-        let uri = unsafe { str::from_utf8_unchecked(uri_slice) };
-        Ok(Status::Complete(uri))
+    if next!(bytes) == b' ' {
+        return Ok(Status::Complete(
+            // SAFETY: all bytes up till `i` must have been `is_token` and therefore also utf-8.
+            unsafe { str::from_utf8_unchecked(bytes.slice_skip(1)) },
+        ));
     } else {
         Err(Error::Token)
     }
@@ -1181,15 +1179,15 @@ fn parse_headers_iter_uninit<'a>(
         #[allow(clippy::never_loop)]
         // parse header name until colon
         let header_name: &str = 'name: loop {
-            let len = simd::match_header_name_vectored(bytes.as_ref());
-            // SAFETY: these bytes have just been matched here above.
-            unsafe { bytes.advance(len) };
-            let bslice = bytes.slice();
+            simd::match_header_name_vectored(bytes);
+            let mut b = next!(bytes);
+
+            // SAFETY: previously bumped by 1 with next! -> always safe.
+            let bslice = unsafe { bytes.slice_skip(1) };
             // SAFETY: previous call to match_header_name_vectored ensured all bytes are valid
             // header name chars, and as such also valid utf-8.
             let name = unsafe { str::from_utf8_unchecked(bslice) };
 
-            let mut b = next!(bytes);
             if b == b':' {
                 break 'name name;
             }
@@ -1215,7 +1213,6 @@ fn parse_headers_iter_uninit<'a>(
             // eat white space between colon and value
             'whitespace_after_colon: loop {
                 b = next!(bytes);
-
                 if b == b' ' || b == b'\t' {
                     bytes.slice();
                     continue 'whitespace_after_colon;
@@ -1242,9 +1239,7 @@ fn parse_headers_iter_uninit<'a>(
             'value_lines: loop {
                 // parse value till EOL
 
-                let len = simd::match_header_value_vectored(bytes.as_ref());
-                // SAFETY: these bytes have just been matched here above.
-                unsafe { bytes.advance(len) };
+                simd::match_header_value_vectored(bytes);
                 let b = next!(bytes);
 
                 //found_ctl

src/simd/avx2.rs

@@ -1,21 +1,18 @@
+use crate::iter::Bytes;
+
 #[inline]
 #[target_feature(enable = "avx2", enable = "sse4.2")]
-pub(crate) unsafe fn match_uri_vectored(bytes: &[u8]) -> usize {
-    let mut len = 0usize;
-    let mut remaining = bytes;
-    while remaining.len() >= 32 {
-        let advance = match_url_char_32_avx(remaining);
-        len = len.saturating_add(advance);
-        remaining = &bytes[len..];
+pub unsafe fn match_uri_vectored(bytes: &mut Bytes) {
+    while bytes.as_ref().len() >= 32 {
+        let advance = match_url_char_32_avx(bytes.as_ref());
+        bytes.advance(advance);
 
         if advance != 32 {
-            return len;
+            return;
         }
     }
     // do both, since avx2 only works when bytes.len() >= 32
-    let advance = super::sse42::match_uri_vectored(remaining);
-    len = len.saturating_add(advance);
-    len
+    super::sse42::match_uri_vectored(bytes)
 }
 
 #[inline(always)]
@@ -60,22 +57,17 @@ unsafe fn match_url_char_32_avx(buf: &[u8]) -> usize {
 }
 
 #[target_feature(enable = "avx2", enable = "sse4.2")]
-pub(crate) unsafe fn match_header_value_vectored(bytes: &[u8]) -> usize {
-    let mut len = 0usize;
-    let mut remaining = bytes;
-    while remaining.len() >= 32 {
-        let advance = match_header_value_char_32_avx(remaining);
-        len = len.saturating_add(advance);
-        remaining = &bytes[len..];
+pub unsafe fn match_header_value_vectored(bytes: &mut Bytes) {
+    while bytes.as_ref().len() >= 32 {
+        let advance = match_header_value_char_32_avx(bytes.as_ref());
+        bytes.advance(advance);
 
         if advance != 32 {
-            return len;
+            return;
         }
     }
     // do both, since avx2 only works when bytes.len() >= 32
-    let advance = super::sse42::match_header_value_vectored(remaining);
-    len = len.saturating_add(advance);
-    len
+    super::sse42::match_header_value_vectored(bytes)
 }
 
 #[inline(always)]
@@ -146,7 +138,7 @@ fn avx2_code_matches_header_value_chars_table() {
 }
 
 #[cfg(test)]
-unsafe fn byte_is_allowed(byte: u8, f: unsafe fn(bytes: &[u8]) -> usize) -> bool {
+unsafe fn byte_is_allowed(byte: u8, f: unsafe fn(bytes: &mut Bytes<'_>)) -> bool {
     let slice = [
         b'_', b'_', b'_', b'_',
         b'_', b'_', b'_', b'_',
@@ -157,9 +149,11 @@ unsafe fn byte_is_allowed(byte: u8, f: unsafe fn(bytes: &[u8]) -> usize) -> bool
         b'_', b'_', byte, b'_',
         b'_', b'_', b'_', b'_',
     ];
+    let mut bytes = Bytes::new(&slice);
+
+    f(&mut bytes);
 
-    let pos = f(&slice);
-    match pos {
+    match bytes.pos() {
         32 => true,
         26 => false,
         _ => unreachable!(),

src/simd/mod.rs

@@ -11,7 +11,7 @@ mod swar;
         )
     ),
 )))]
-pub(crate) use self::swar::*;
+pub use self::swar::*;
 
 #[cfg(all(
     httparse_simd,
@@ -59,7 +59,7 @@ mod runtime;
         target_arch = "x86_64",
     ),
 ))]
-pub(crate) use self::runtime::*;
+pub use self::runtime::*;
 
 #[cfg(all(
     httparse_simd,
@@ -72,18 +72,18 @@ pub(crate) use self::runtime::*;
 ))]
 mod sse42_compile_time {
     #[inline(always)]
-    pub(crate) fn match_header_name_vectored(b: &[u8]) -> usize {
-        super::swar::match_header_name_vectored(b)
+    pub fn match_header_name_vectored(b: &mut crate::iter::Bytes<'_>) {
+        super::swar::match_header_name_vectored(b);
     }
 
     #[inline(always)]
-    pub(crate) fn match_uri_vectored(b: &[u8]) -> usize {
+    pub fn match_uri_vectored(b: &mut crate::iter::Bytes<'_>) {
         // SAFETY: calls are guarded by a compile time feature check
         unsafe { crate::simd::sse42::match_uri_vectored(b) }
     }
-
+    
     #[inline(always)]
-    pub(crate) fn match_header_value_vectored(b: &[u8]) -> usize {
+    pub fn match_header_value_vectored(b: &mut crate::iter::Bytes<'_>) {
         // SAFETY: calls are guarded by a compile time feature check
         unsafe { crate::simd::sse42::match_header_value_vectored(b) }
     }
@@ -98,7 +98,7 @@ mod sse42_compile_time {
         target_arch = "x86_64",
     ),
 ))]
-pub(crate) use self::sse42_compile_time::*;
+pub use self::sse42_compile_time::*;
 
 #[cfg(all(
     httparse_simd,
@@ -110,18 +110,18 @@ pub(crate) use self::sse42_compile_time::*;
 ))]
 mod avx2_compile_time {
     #[inline(always)]
-    pub(crate) fn match_header_name_vectored(b: &[u8]) -> usize {
-        super::swar::match_header_name_vectored(b)
+    pub fn match_header_name_vectored(b: &mut crate::iter::Bytes<'_>) {
+        super::swar::match_header_name_vectored(b);
     }
 
     #[inline(always)]
-    pub(crate) fn match_uri_vectored(b: &[u8]) -> usize {
+    pub fn match_uri_vectored(b: &mut crate::iter::Bytes<'_>) {
         // SAFETY: calls are guarded by a compile time feature check
         unsafe { crate::simd::avx2::match_uri_vectored(b) }
     }
-
+    
     #[inline(always)]
-    pub(crate) fn match_header_value_vectored(b: &[u8]) -> usize {
+    pub fn match_header_value_vectored(b: &mut crate::iter::Bytes<'_>) {
         // SAFETY: calls are guarded by a compile time feature check
         unsafe { crate::simd::avx2::match_header_value_vectored(b) }
     }
@@ -135,7 +135,7 @@ mod avx2_compile_time {
         target_arch = "x86_64",
     ),
 ))]
-pub(crate) use self::avx2_compile_time::*;
+pub use self::avx2_compile_time::*;
 
 #[cfg(all(
     httparse_simd,
@@ -149,4 +149,4 @@ mod neon;
     target_arch = "aarch64",
     httparse_simd_neon_intrinsics,
 ))]
-pub(crate) use self::neon::*;
+pub use self::neon::*;