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package bolt
import (
"bytes"
"unsafe"
)
// branch represents a temporary in-memory branch page.
type branch struct {
parent *branch
items branchItems
}
// put adds a new node or replaces an existing node.
func (b *branch) put(id pgid, newid pgid, key []byte, replace bool) {
var index int
for ; index < len(b.items); index++ {
if b.items[index].pgid == id {
break
}
}
if !replace {
index++
b.items = append(b.items, branchItem{})
if index < len(b.items) {
copy(b.items[index+1:], b.items[index:])
}
}
b.items[index].pgid = newid
b.items[index].key = key
}
// read initializes the item data from an on-disk page.
func (b *branch) read(page *page) {
ncount := int(page.count)
b.items = make(branchItems, ncount)
bnodes := (*[maxNodesPerPage]bnode)(unsafe.Pointer(&page.ptr))
for i := 0; i < ncount; i++ {
bnode := &bnodes[i]
item := &b.items[i]
item.key = bnode.key()
}
}
type branchItems []branchItem
type branchItem struct {
pgid pgid
key []byte
}
func (s branchItems) Len() int { return len(s) }
func (s branchItems) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s branchItems) Less(i, j int) bool { return bytes.Compare(s[i].key, s[j].key) == -1 }
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