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author | Wim <wim@42.be> | 2020-08-10 00:29:54 +0200 |
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committer | GitHub <noreply@github.com> | 2020-08-10 00:29:54 +0200 |
commit | 4e50fd864921c556988c919269448efdb90fa961 (patch) | |
tree | a3625f03f8de3c4f3841364000a4ea3aa42c1533 /vendor/google.golang.org/protobuf/internal/strs/strings_unsafe.go | |
parent | dfdffa0027334e55ce213fc6eb62206dbf48baf6 (diff) | |
download | matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.tar.gz matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.tar.bz2 matterbridge-msglm-4e50fd864921c556988c919269448efdb90fa961.zip |
Use mattermost v5 module (#1192)
Diffstat (limited to 'vendor/google.golang.org/protobuf/internal/strs/strings_unsafe.go')
-rw-r--r-- | vendor/google.golang.org/protobuf/internal/strs/strings_unsafe.go | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/internal/strs/strings_unsafe.go b/vendor/google.golang.org/protobuf/internal/strs/strings_unsafe.go new file mode 100644 index 00000000..2160c701 --- /dev/null +++ b/vendor/google.golang.org/protobuf/internal/strs/strings_unsafe.go @@ -0,0 +1,94 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build !purego,!appengine + +package strs + +import ( + "unsafe" + + pref "google.golang.org/protobuf/reflect/protoreflect" +) + +type ( + stringHeader struct { + Data unsafe.Pointer + Len int + } + sliceHeader struct { + Data unsafe.Pointer + Len int + Cap int + } +) + +// UnsafeString returns an unsafe string reference of b. +// The caller must treat the input slice as immutable. +// +// WARNING: Use carefully. The returned result must not leak to the end user +// unless the input slice is provably immutable. +func UnsafeString(b []byte) (s string) { + src := (*sliceHeader)(unsafe.Pointer(&b)) + dst := (*stringHeader)(unsafe.Pointer(&s)) + dst.Data = src.Data + dst.Len = src.Len + return s +} + +// UnsafeBytes returns an unsafe bytes slice reference of s. +// The caller must treat returned slice as immutable. +// +// WARNING: Use carefully. The returned result must not leak to the end user. +func UnsafeBytes(s string) (b []byte) { + src := (*stringHeader)(unsafe.Pointer(&s)) + dst := (*sliceHeader)(unsafe.Pointer(&b)) + dst.Data = src.Data + dst.Len = src.Len + dst.Cap = src.Len + return b +} + +// Builder builds a set of strings with shared lifetime. +// This differs from strings.Builder, which is for building a single string. +type Builder struct { + buf []byte +} + +// AppendFullName is equivalent to protoreflect.FullName.Append, +// but optimized for large batches where each name has a shared lifetime. +func (sb *Builder) AppendFullName(prefix pref.FullName, name pref.Name) pref.FullName { + n := len(prefix) + len(".") + len(name) + if len(prefix) == 0 { + n -= len(".") + } + sb.grow(n) + sb.buf = append(sb.buf, prefix...) + sb.buf = append(sb.buf, '.') + sb.buf = append(sb.buf, name...) + return pref.FullName(sb.last(n)) +} + +// MakeString is equivalent to string(b), but optimized for large batches +// with a shared lifetime. +func (sb *Builder) MakeString(b []byte) string { + sb.grow(len(b)) + sb.buf = append(sb.buf, b...) + return sb.last(len(b)) +} + +func (sb *Builder) grow(n int) { + if cap(sb.buf)-len(sb.buf) >= n { + return + } + + // Unlike strings.Builder, we do not need to copy over the contents + // of the old buffer since our builder provides no API for + // retrieving previously created strings. + sb.buf = make([]byte, 2*(cap(sb.buf)+n)) +} + +func (sb *Builder) last(n int) string { + return UnsafeString(sb.buf[len(sb.buf)-n:]) +} |