refactor(h1): delete the unused SIMD header scan and stop advertising a SIMD parser (celeris#424)

README.md

@@ -32,7 +32,7 @@ An engine-correctness release, driven by what the [probatorium](https://github.c
 - **Edge-triggered epoll** — per-core event loops with CPU pinning.
 - **Adaptive meta-engine** — transplants between io_uring and epoll at runtime based on telemetry.
 - **First-party database drivers** — native [`driver/postgres`](driver/postgres), [`driver/redis`](driver/redis), and [`driver/memcached`](driver/memcached) run on the celeris event loop (see [Database drivers](#database-drivers)).
-- **SIMD HTTP parser** — SSE2 (amd64) and NEON (arm64) with a generic SWAR fallback.
+- **Zero-copy HTTP/1.1 parser** — the parser returns header and body slices that alias the bytes it parses instead of copying them. On epoll and io_uring, a request that arrives whole in one read, with no body or a `Content-Length` body, and runs inline is parsed in place in the engine's read buffer; a request that spans reads, has a chunked body, or runs on an async handler is served from a per-connection buffer instead.
 - **HTTP/2 cleartext (h2c)** — full stream multiplexing, flow control, HPACK, inline handler execution, zero-alloc HEADERS fast path.
 - **Auto-detect** — protocol negotiation from the first bytes on the wire.
 - **Error-returning handlers** — `HandlerFunc` returns `error`; structured `*HTTPError` carries status codes.

protocol/h1/bench_test.go

@@ -84,38 +84,3 @@ func BenchmarkParseRequest_Pipelined(b *testing.B) {
 		}
 	}
 }
-
-func BenchmarkFindHeaderEnd(b *testing.B) {
-	sizes := []int{64, 256, 1024, 4096}
-	for _, size := range sizes {
-		b.Run(fmt.Sprintf("size=%d", size), func(b *testing.B) {
-			// Place \r\n\r\n at the end
-			buf := make([]byte, size)
-			for i := range buf {
-				buf[i] = 'A'
-			}
-			copy(buf[size-4:], "\r\n\r\n")
-			b.SetBytes(int64(size))
-			b.ReportAllocs()
-			b.ResetTimer()
-			for i := 0; i < b.N; i++ {
-				findHeaderEnd(buf)
-			}
-		})
-	}
-}
-
-func BenchmarkFindHeaderEnd_8K(b *testing.B) {
-	size := 8192
-	buf := make([]byte, size)
-	for i := range buf {
-		buf[i] = 'A'
-	}
-	copy(buf[size-4:], "\r\n\r\n")
-	b.SetBytes(int64(size))
-	b.ReportAllocs()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		findHeaderEnd(buf)
-	}
-}

protocol/h1/doc.go

@@ -1,11 +1,13 @@
 // Package h1 implements a zero-copy HTTP/1.1 parser.
 //
 // This is a low-level parser package consumed by the celeris engine layer
-// (engine/iouring, engine/epoll, engine/std bridge); application code
-// should not import it directly. The parser returns header and body slices
-// that alias the connection's read buffer — callers must materialize
-// (clone) any value they retain past the next [ParseRequest] call on the
-// same connection.
+// (engine/epoll and engine/iouring, through internal/conn; the std engine
+// uses net/http's parser); application code should not import it directly.
+// The parser returns header and body slices that alias the buffer passed to
+// [Parser.Reset]: an engine's read buffer, or a per-connection buffer the
+// engine gathered the request into. Callers must materialize (clone) any
+// value they retain past the next [Parser.ParseRequest] call on the same
+// connection.
 //
 // # Documentation
 //

protocol/h1/parser.go

@@ -86,7 +86,7 @@ func (p *Parser) ParseRequest(req *Request) (int, error) {
 		return 0, nil
 	}
 
-	// No upfront whole-block findHeaderEnd scan: parseHeaders detects an
+	// No upfront whole-block CRLFCRLF scan: parseHeaders detects an
 	// incomplete block itself (a final line with no CRLF yields lineEnd==-1 →
 	// (false,nil)), and every caller Reset()s parser+req before re-parsing, so
 	// a partial parse is always retried cleanly. Scanning here first would