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package fzf
import "sync"
// Chunk is a list of Items whose size has the upper limit of chunkSize
type Chunk struct {
items [chunkSize]Item
count int
}
// ItemBuilder is a closure type that builds Item object from byte array
type ItemBuilder func(*Item, []byte) bool
// ChunkList is a list of Chunks
type ChunkList struct {
chunks []*Chunk
mutex sync.Mutex
trans ItemBuilder
}
// NewChunkList returns a new ChunkList
func NewChunkList(trans ItemBuilder) *ChunkList {
return &ChunkList{
chunks: []*Chunk{},
mutex: sync.Mutex{},
trans: trans}
}
func (c *Chunk) push(trans ItemBuilder, data []byte) bool {
if trans(&c.items[c.count], data) {
c.count++
return true
}
return false
}
// IsFull returns true if the Chunk is full
func (c *Chunk) IsFull() bool {
return c.count == chunkSize
}
func (cl *ChunkList) lastChunk() *Chunk {
return cl.chunks[len(cl.chunks)-1]
}
// CountItems returns the total number of Items
func CountItems(cs []*Chunk) int {
if len(cs) == 0 {
return 0
}
return chunkSize*(len(cs)-1) + cs[len(cs)-1].count
}
// Push adds the item to the list
func (cl *ChunkList) Push(data []byte) bool {
cl.mutex.Lock()
if len(cl.chunks) == 0 || cl.lastChunk().IsFull() {
cl.chunks = append(cl.chunks, &Chunk{})
}
ret := cl.lastChunk().push(cl.trans, data)
cl.mutex.Unlock()
return ret
}
// Clear clears the data
func (cl *ChunkList) Clear() {
cl.mutex.Lock()
cl.chunks = nil
cl.mutex.Unlock()
}
// Snapshot returns immutable snapshot of the ChunkList
func (cl *ChunkList) Snapshot() ([]*Chunk, int) {
cl.mutex.Lock()
ret := make([]*Chunk, len(cl.chunks))
copy(ret, cl.chunks)
// Duplicate the last chunk
if cnt := len(ret); cnt > 0 {
newChunk := *ret[cnt-1]
ret[cnt-1] = &newChunk
}
cl.mutex.Unlock()
return ret, CountItems(ret)
}
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