1 files changed, 107 insertions, 0 deletions
diff --git a/buckets.go b/buckets.go
new file mode 100644
index 0000000..59a82d8
--- /dev/null
+++ b/buckets.go
@@ -0,0 +1,107 @@
+package bolt
+
+import (
+	"sort"
+	"unsafe"
+)
+
+// buckets represents a in-memory buckets page.
+type buckets struct {
+	pgid    pgid
+	items map[string]*bucket
+}
+
+// size returns the size of the page after serialization.
+func (b *buckets) size() int {
+	var size int = pageHeaderSize
+	for key, _ := range b.items {
+		size += int(unsafe.Sizeof(bucket{})) + len(key)
+	}
+	return size
+}
+
+// get retrieves a bucket by name.
+func (b *buckets) get(key string) *bucket {
+	return b.items[key]
+}
+
+// put sets a new value for a bucket.
+func (b *buckets) put(key string, item *bucket) {
+	b.items[key] = item
+}
+
+// del deletes a bucket by name.
+func (b *buckets) del(key string) {
+	if item := b.items[key]; item != nil {
+		delete(b.items, key)
+	}
+}
+
+// read initializes the data from an on-disk page.
+func (b *buckets) read(p *page) {
+	b.pgid = p.id
+	b.items = make(map[string]*bucket)
+
+	var items []*bucket
+	var keys []string
+
+	// Read items.
+	nodes := (*[maxNodesPerPage]bucket)(unsafe.Pointer(&p.ptr))
+	for i := 0; i < int(p.count); i++ {
+		node := &nodes[i]
+		items = append(items, node)
+	}
+
+	// Read keys.
+	buf := (*[maxAllocSize]byte)(unsafe.Pointer(&nodes[p.count]))[:]
+	for i := 0; i < int(p.count); i++ {
+		size := int(buf[0])
+		buf = buf[1:]
+		keys = append(keys, string(buf[:size]))
+		buf = buf[size:]
+	}
+
+	// Associate keys and items.
+	for index, key := range keys {
+		b.items[key] = &bucket{items[index].root}
+	}
+}
+
+// write writes the items onto a page.
+func (b *buckets) write(p *page) {
+	// Initialize page.
+	p.flags |= p_buckets
+	p.count = uint16(len(b.items))
+
+	// Sort keys.
+	var keys []string
+	for key, _ := range b.items {
+		keys = append(keys, key)
+	}
+	sort.StringSlice(keys).Sort()
+
+	// Write each bucket to the page.
+	items := (*[maxNodesPerPage]bucket)(unsafe.Pointer(&p.ptr))
+	for index, key := range keys {
+		items[index] = *b.items[key]
+	}
+
+	// Write each key to the page.
+	buf := (*[maxAllocSize]byte)(unsafe.Pointer(&items[p.count]))[:]
+	for _, key := range keys {
+		buf[0] = byte(len(key))
+		buf = buf[1:]
+		copy(buf, []byte(key))
+		buf = buf[len(key):]
+	}
+}
+
+// updateRoot finds a bucket by root id and then updates it to point to a new root.
+func (b *buckets) updateRoot(oldid, newid pgid) {
+	for _, b := range b.items {
+		if b.root == oldid {
+			b.root = newid
+			return
+		}
+	}
+}