mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
69 lines
1.8 KiB
Go
69 lines
1.8 KiB
Go
// Copyright 2024 The etcd Authors
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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 main
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import "unsafe"
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const pageHeaderSize = unsafe.Sizeof(page{})
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const leafPageElementSize = unsafe.Sizeof(leafPageElement{})
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const pageMaxAllocSize = 0xFFFFFFF
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const (
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leafPageFlag = 0x02
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)
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type page struct {
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id uint64
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flags uint16
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count uint16
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overflow uint32
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}
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func (p *page) isLeafPage() bool {
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return p.flags == leafPageFlag
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}
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func loadPage(buf []byte) *page {
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return (*page)(unsafe.Pointer(&buf[0]))
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}
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// leafPageElement retrieves the leaf node by index
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func (p *page) leafPageElement(index uint16) *leafPageElement {
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return (*leafPageElement)(unsafeIndex(unsafe.Pointer(p), unsafe.Sizeof(*p),
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leafPageElementSize, int(index)))
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}
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// leafPageElement represents a node on a leaf page.
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type leafPageElement struct {
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flags uint32
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pos uint32
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ksize uint32
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vsize uint32
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}
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// Key returns a byte slice of the node key.
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func (n *leafPageElement) key() []byte {
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i := int(n.pos)
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j := i + int(n.ksize)
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return unsafeByteSlice(unsafe.Pointer(n), 0, i, j)
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}
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// Value returns a byte slice of the node value.
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func (n *leafPageElement) value() []byte {
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i := int(n.pos) + int(n.ksize)
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j := i + int(n.vsize)
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return unsafeByteSlice(unsafe.Pointer(n), 0, i, j)
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}
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