Use unsafe.Slice where possible (#80)

options.go

@@ -6,7 +6,6 @@ import "C"
 
 import (
 	"fmt"
-	"reflect"
 	"unsafe"
 )
 
@@ -2472,10 +2471,7 @@ func LoadLatestOptions(path string, env *Env, ignoreUnknownOpts bool, cache *Cac
 
 	if err = fromCError(cErr); err == nil {
 		// convert **C.rocksdb_options_t into []Options
-		var cfOptions_ []*C.rocksdb_options_t
-		sH := (*reflect.SliceHeader)(unsafe.Pointer(&cfOptions_))
-		sH.Cap, sH.Len, sH.Data = int(numCF), int(numCF), uintptr(unsafe.Pointer(cfOpts))
-
+		cfOptions_ := unsafe.Slice(cfOpts, int(numCF))
 		cfOptions := make([]Options, int(numCF))
 		for i := range cfOptions {
 			cfOptions[i] = Options{c: cfOptions_[i]}

util.go

@@ -5,7 +5,6 @@ package grocksdb
 import "C"
 import (
 	"errors"
-	"reflect"
 	"unsafe"
 )
 
@@ -24,10 +23,7 @@ func charToBool(c C.uchar) bool {
 
 // charToByte converts a *C.char to a byte slice.
 func charToByte(data *C.char, len C.size_t) []byte {
-	var value []byte
-	sH := (*reflect.SliceHeader)(unsafe.Pointer(&value))
-	sH.Cap, sH.Len, sH.Data = int(len), int(len), uintptr(unsafe.Pointer(data))
-	return value
+	return unsafe.Slice((*byte)(unsafe.Pointer(data)), int(len))
 }
 
 // byteToChar returns *C.char from byte slice.
@@ -51,10 +47,7 @@ func cByteSlice(b []byte) *C.char {
 
 // charSlice converts a C array of *char to a []*C.char.
 func charSlice(data **C.char, len C.int) []*C.char {
-	var value []*C.char
-	sH := (*reflect.SliceHeader)(unsafe.Pointer(&value))
-	sH.Cap, sH.Len, sH.Data = int(len), int(len), uintptr(unsafe.Pointer(data))
-	return value
+	return unsafe.Slice(data, int(len))
 }
 
 // charSliceIntoStringSlice converts a C array of *char to a []string.
@@ -71,10 +64,7 @@ func charSliceIntoStringSlice(data **C.char, len C.int) []string {
 
 // sizeSlice converts a C array of size_t to a []C.size_t.
 func sizeSlice(data *C.size_t, len C.int) []C.size_t {
-	var value []C.size_t
-	sH := (*reflect.SliceHeader)(unsafe.Pointer(&value))
-	sH.Cap, sH.Len, sH.Data = int(len), int(len), uintptr(unsafe.Pointer(data))
-	return value
+	return unsafe.Slice(data, int(len))
 }
 
 // fromCError returns go error and free c_err if need.