94 lines
1.8 KiB
Go
94 lines
1.8 KiB
Go
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package storage
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import (
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"bytes"
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"encoding/json"
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"os"
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"git.nicholasnovak.io/nnovak/spatial-db/world"
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)
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// A `UnityFile` is a collection of chunks, stored as a single file on disk
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//
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// This is done because with worlds that span millions of chunks, the speed to
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// access individual files slows down
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type UnityFile struct {
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fd *os.File
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fileSize int
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// metadata maps the position of a chunk to its start index within the file
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metadata map[world.ChunkPos]int
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}
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func CreateUnityFile(fileName string) (UnityFile, error) {
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var u UnityFile
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f, err := os.Create(fileName)
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if err != nil {
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return u, err
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}
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u.fd = f
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u.metadata = make(map[world.ChunkPos]int)
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return u, nil
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}
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func (u UnityFile) Size() int {
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return u.fileSize
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}
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func (u *UnityFile) WriteChunk(data world.ChunkData) error {
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var encoded bytes.Buffer
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// Encode the chunk first
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if err := json.NewEncoder(&encoded).Encode(data); err != nil {
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return err
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}
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encodedSize := encoded.Len()
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// Go to the end of the file
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u.fd.Seek(0, u.fileSize)
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// Write the encoded contents to the file
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if _, err := u.fd.Write(encoded.Bytes()); err != nil {
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return err
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}
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// Update the metadata with the new file
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u.metadata[data.Pos] = u.fileSize
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u.fileSize += encodedSize
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return nil
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}
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func (u UnityFile) WriteMetadataFile(fileName string) error {
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fd, err := os.OpenFile(fileName, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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if err != nil {
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return err
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}
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defer fd.Close()
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if err := json.NewEncoder(fd).Encode(&u.metadata); err != nil {
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return err
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}
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return nil
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}
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func (u *UnityFile) ReadMetadataFile(fileName string) error {
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fd, err := os.Open(fileName)
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if err != nil {
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return err
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}
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if err := json.NewDecoder(fd).Decode(&u.metadata); err != nil {
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return err
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}
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return nil
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}
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func (u UnityFile) ReadChunk() world.ChunkData {
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return world.ChunkData{}
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}
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