.

vendor/github.com/andybalholm/brotli/find_match_length.go

@@ -0,0 +1,45 @@
+package brotli
+
+import (
+	"encoding/binary"
+	"math/bits"
+	"runtime"
+)
+
+/* Copyright 2010 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* Function to find maximal matching prefixes of strings. */
+func findMatchLengthWithLimit(s1 []byte, s2 []byte, limit uint) uint {
+	var matched uint = 0
+	_, _ = s1[limit-1], s2[limit-1] // bounds check
+	switch runtime.GOARCH {
+	case "amd64":
+		// Compare 8 bytes at at time.
+		for matched+8 <= limit {
+			w1 := binary.LittleEndian.Uint64(s1[matched:])
+			w2 := binary.LittleEndian.Uint64(s2[matched:])
+			if w1 != w2 {
+				return matched + uint(bits.TrailingZeros64(w1^w2)>>3)
+			}
+			matched += 8
+		}
+	case "386":
+		// Compare 4 bytes at at time.
+		for matched+4 <= limit {
+			w1 := binary.LittleEndian.Uint32(s1[matched:])
+			w2 := binary.LittleEndian.Uint32(s2[matched:])
+			if w1 != w2 {
+				return matched + uint(bits.TrailingZeros32(w1^w2)>>3)
+			}
+			matched += 4
+		}
+	}
+	for matched < limit && s1[matched] == s2[matched] {
+		matched++
+	}
+	return matched
+}