util.go

package gorocksdb

// #include <stdlib.h>
import "C"
import (
	"reflect"
	"unsafe"
)

// btoi converts a bool value to int.
func btoi(b bool) int {
	if b {
		return 1
	}
	return 0
}

// boolToChar converts a bool value to C.uchar.
func boolToChar(b bool) C.uchar {
	if b {
		return 1
	}
	return 0
}

// 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
}

// cBackedBytes returs a copy of the same byte slice which is backed by
// malloced memory. This should be freed using freeCBackedBytes.
func cBackedBytes(data []byte) []byte {
	return charToByte(cByteSlice(data), C.size_t(len(data)))
}

// freeCBackedBytes frees a byte slice created by cBackedBytes
func freeCBackedBytes(data []byte) {
	sH := (*reflect.SliceHeader)(unsafe.Pointer(&data))
	C.free(unsafe.Pointer(sH.Data))

}

// byteToChar returns *C.char from byte slice.
func byteToChar(b []byte) *C.char {
	var c *C.char
	if len(b) > 0 {
		c = (*C.char)(unsafe.Pointer(&b[0]))
	}
	return c
}

// Go []byte to C string
// The C string is allocated in the C heap using malloc.
func cByteSlice(b []byte) *C.char {
	var c *C.char
	if len(b) > 0 {
		c = (*C.char)(C.CBytes(b))
	}
	return c
}

// stringToChar returns *C.char from string.
// func stringToChar(s string) *C.char {
// 	ptrStr := (*reflect.StringHeader)(unsafe.Pointer(&s))
// 	return (*C.char)(unsafe.Pointer(ptrStr.Data))
// }

// 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
}

// 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
}