go-ceph/internal/cutil/iovec.go

61 lines
1.2 KiB
Go

package cutil
/*
#include <stdlib.h>
#include <sys/uio.h>
*/
import "C"
import (
"unsafe"
)
// Iovec is a slice of iovec structs. Might have allocated C memory, so it must
// be freed with the Free() method.
type Iovec struct {
iovec []C.struct_iovec
sbs []*SyncBuffer
}
const iovecSize = C.sizeof_struct_iovec
// ByteSlicesToIovec creates an Iovec and links it to Go buffers in data.
func ByteSlicesToIovec(data [][]byte) (v Iovec) {
n := len(data)
iovecMem := C.malloc(iovecSize * C.size_t(n))
v.iovec = (*[MaxIdx]C.struct_iovec)(iovecMem)[:n:n]
for i, b := range data {
sb := NewSyncBuffer(CPtr(&v.iovec[i].iov_base), b)
v.sbs = append(v.sbs, sb)
v.iovec[i].iov_len = C.size_t(len(b))
}
return
}
// Sync makes sure the slices contain the same as the C buffers
func (v *Iovec) Sync() {
for _, sb := range v.sbs {
sb.Sync()
}
}
// Pointer returns a pointer to the iovec
func (v *Iovec) Pointer() unsafe.Pointer {
return unsafe.Pointer(&v.iovec[0])
}
// Len returns a pointer to the iovec
func (v *Iovec) Len() int {
return len(v.iovec)
}
// Free the C memory in the Iovec.
func (v *Iovec) Free() {
for _, sb := range v.sbs {
sb.Release()
}
if len(v.iovec) != 0 {
C.free(unsafe.Pointer(&v.iovec[0]))
}
v.iovec = nil
}