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|
package common
import (
"fmt"
"io"
"os"
"unsafe"
)
func LoadBucket(buf []byte) *InBucket {
return (*InBucket)(unsafe.Pointer(&buf[0]))
}
func LoadPage(buf []byte) *Page {
return (*Page)(unsafe.Pointer(&buf[0]))
}
func LoadPageMeta(buf []byte) *Meta {
return (*Meta)(unsafe.Pointer(&buf[PageHeaderSize]))
}
func CopyFile(srcPath, dstPath string) error {
// Ensure source file exists.
_, err := os.Stat(srcPath)
if os.IsNotExist(err) {
return fmt.Errorf("source file %q not found", srcPath)
} else if err != nil {
return err
}
// Ensure output file not exist.
_, err = os.Stat(dstPath)
if err == nil {
return fmt.Errorf("output file %q already exists", dstPath)
} else if !os.IsNotExist(err) {
return err
}
srcDB, err := os.Open(srcPath)
if err != nil {
return fmt.Errorf("failed to open source file %q: %w", srcPath, err)
}
defer srcDB.Close()
dstDB, err := os.Create(dstPath)
if err != nil {
return fmt.Errorf("failed to create output file %q: %w", dstPath, err)
}
defer dstDB.Close()
written, err := io.Copy(dstDB, srcDB)
if err != nil {
return fmt.Errorf("failed to copy database file from %q to %q: %w", srcPath, dstPath, err)
}
srcFi, err := srcDB.Stat()
if err != nil {
return fmt.Errorf("failed to get source file info %q: %w", srcPath, err)
}
initialSize := srcFi.Size()
if initialSize != written {
return fmt.Errorf("the byte copied (%q: %d) isn't equal to the initial db size (%q: %d)", dstPath, written, srcPath, initialSize)
}
return nil
}
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