ledisdb/vendor/gomdb/val.go

55 lines
1.1 KiB
Go

// +build lmdb
package mdb
/*
#cgo CFLAGS: -pthread -W -Wall -Wno-unused-parameter -Wbad-function-cast -O2 -g
#cgo CFLAGS: -I/usr/local
#include <stdlib.h>
#include <stdio.h>
#include "lmdb.h"
*/
import "C"
import (
"reflect"
"unsafe"
)
// MDB_val
type Val C.MDB_val
// Create a Val that points to p's data. the Val's data must not be freed
// manually and C references must not survive the garbage collection of p (and
// the returned Val).
func Wrap(p []byte) Val {
if len(p) == 0 {
return Val(C.MDB_val{})
}
return Val(C.MDB_val{
mv_size: C.size_t(len(p)),
mv_data: unsafe.Pointer(&p[0]),
})
}
// If val is nil, a empty slice is retured.
func (val Val) Bytes() []byte {
return C.GoBytes(val.mv_data, C.int(val.mv_size))
}
// If val is nil, a empty slice is retured.
func (val Val) BytesNoCopy() []byte {
hdr := reflect.SliceHeader{
Data: uintptr(unsafe.Pointer(val.mv_data)),
Len: int(val.mv_size),
Cap: int(val.mv_size),
}
return *(*[]byte)(unsafe.Pointer(&hdr))
}
// If val is nil, an empty string is returned.
func (val Val) String() string {
return C.GoStringN((*C.char)(val.mv_data), C.int(val.mv_size))
}