mirror of https://github.com/etcd-io/bbolt.git
58 lines
1.0 KiB
Go
58 lines
1.0 KiB
Go
package bolt
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import (
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"bytes"
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"unsafe"
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)
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const maxPageSize = 0x8000
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const minKeyCount = 2
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const pageHeaderSize = int(unsafe.Offsetof(((*page)(nil)).data))
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const minPageKeys = 2
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const fillThreshold = 250 // 25%
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const (
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p_branch = 0x01
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p_leaf = 0x02
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p_meta = 0x04
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)
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type pgid uint64
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type page struct {
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id pgid
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flags uint32
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lower uint16
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upper uint16
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count uint32
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data uintptr
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}
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// meta returns a pointer to the metadata section of the page.
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func (p *page) meta() (*meta, error) {
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// Exit if page is not a meta page.
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if (p.flags & p_meta) == 0 {
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return nil, InvalidMetaPageError
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}
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// Cast the meta section and validate before returning.
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m := (*meta)(unsafe.Pointer(&p.ptr))
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if err := m.validate(); err != nil {
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return nil, err
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}
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return m, nil
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}
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// init initializes a page as a new meta page.
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func (p *page) init(pageSize int) {
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p.flags = p_meta
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m := (*meta)(unsafe.Pointer(&p.ptr))
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m.magic = magic
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m.version = version
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m.pageSize = uint32(pageSize)
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m.pgid = 1
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m.buckets.root = 0
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}
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