mirror of
https://gitee.com/milvus-io/milvus.git
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c4ae9f4ece
related: https://github.com/milvus-io/milvus/issues/39173 Signed-off-by: shaoting-huang <shaoting.huang@zilliz.com>
117 lines
2.3 KiB
Go
117 lines
2.3 KiB
Go
// Copyright 2023 Zilliz
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package file
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import (
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"io"
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"github.com/cockroachdb/errors"
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)
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var errInvalid = errors.New("invalid argument")
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type MemoryFile struct {
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b []byte
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i int
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}
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func (f *MemoryFile) Close() error {
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return nil
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}
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func (f *MemoryFile) Read(p []byte) (n int, err error) {
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if f.i >= len(f.b) {
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return 0, io.EOF
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}
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n = copy(p, f.b[f.i:])
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f.i += n
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return n, nil
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}
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func (f *MemoryFile) Write(b []byte) (int, error) {
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n, err := f.writeAt(b, int64(f.i))
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f.i += n
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return n, err
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}
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func (f *MemoryFile) writeAt(b []byte, off int64) (int, error) {
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if off < 0 || int64(int(off)) < off {
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return 0, errInvalid
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}
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if off > int64(len(f.b)) {
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f.truncate(off)
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}
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n := copy(f.b[off:], b)
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f.b = append(f.b, b[n:]...)
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return len(b), nil
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}
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func (f *MemoryFile) truncate(n int64) error {
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switch {
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case n < 0 || int64(int(n)) < n:
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return errInvalid
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case n <= int64(len(f.b)):
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f.b = f.b[:n]
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return nil
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default:
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f.b = append(f.b, make([]byte, int(n)-len(f.b))...)
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return nil
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}
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}
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func (f *MemoryFile) ReadAt(b []byte, off int64) (n int, err error) {
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if off < 0 || int64(int(off)) < off {
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return 0, errInvalid
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}
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if off > int64(len(f.b)) {
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return 0, io.EOF
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}
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n = copy(b, f.b[off:])
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f.i += n
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if n < len(b) {
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return n, io.EOF
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}
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return n, nil
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}
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func (f *MemoryFile) Seek(offset int64, whence int) (int64, error) {
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var abs int64
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switch whence {
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case io.SeekStart:
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abs = offset
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case io.SeekCurrent:
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abs = int64(f.i) + offset
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case io.SeekEnd:
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abs = int64(len(f.b)) + offset
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default:
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return 0, errInvalid
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}
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if abs < 0 {
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return 0, errInvalid
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}
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f.i = int(abs)
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return abs, nil
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}
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func (f *MemoryFile) Bytes() []byte {
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return f.b
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}
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func NewMemoryFile(b []byte) *MemoryFile {
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return &MemoryFile{
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b: b,
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}
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}
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