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authorWim <wim@42.be>2018-11-13 00:02:07 +0100
committerWim <wim@42.be>2018-11-13 00:02:07 +0100
commitf8dc24bc09fc1981637ac5c4a210780ac5512944 (patch)
tree0df78ce10744dbf3b25accdcb215a9b7b87b7e89 /vendor/golang.org/x/crypto/internal/chacha20/xor.go
parente9419f10d3d24e24c9cedab93104c418f383782c (diff)
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Switch back go upstream bwmarrin/discordgo
Commit https://github.com/bwmarrin/discordgo/commit/ffa9956c9b41e8e2a10c26a254389854e016b006 got merged in.
Diffstat (limited to 'vendor/golang.org/x/crypto/internal/chacha20/xor.go')
-rw-r--r--vendor/golang.org/x/crypto/internal/chacha20/xor.go43
1 files changed, 43 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/internal/chacha20/xor.go b/vendor/golang.org/x/crypto/internal/chacha20/xor.go
new file mode 100644
index 00000000..9c5ba0b3
--- /dev/null
+++ b/vendor/golang.org/x/crypto/internal/chacha20/xor.go
@@ -0,0 +1,43 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found src the LICENSE file.
+
+package chacha20
+
+import (
+ "runtime"
+)
+
+// Platforms that have fast unaligned 32-bit little endian accesses.
+const unaligned = runtime.GOARCH == "386" ||
+ runtime.GOARCH == "amd64" ||
+ runtime.GOARCH == "arm64" ||
+ runtime.GOARCH == "ppc64le" ||
+ runtime.GOARCH == "s390x"
+
+// xor reads a little endian uint32 from src, XORs it with u and
+// places the result in little endian byte order in dst.
+func xor(dst, src []byte, u uint32) {
+ _, _ = src[3], dst[3] // eliminate bounds checks
+ if unaligned {
+ // The compiler should optimize this code into
+ // 32-bit unaligned little endian loads and stores.
+ // TODO: delete once the compiler does a reliably
+ // good job with the generic code below.
+ // See issue #25111 for more details.
+ v := uint32(src[0])
+ v |= uint32(src[1]) << 8
+ v |= uint32(src[2]) << 16
+ v |= uint32(src[3]) << 24
+ v ^= u
+ dst[0] = byte(v)
+ dst[1] = byte(v >> 8)
+ dst[2] = byte(v >> 16)
+ dst[3] = byte(v >> 24)
+ } else {
+ dst[0] = src[0] ^ byte(u)
+ dst[1] = src[1] ^ byte(u>>8)
+ dst[2] = src[2] ^ byte(u>>16)
+ dst[3] = src[3] ^ byte(u>>24)
+ }
+}