mobile/bind/objc/seq_darwin.go.support

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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
// Go support functions for Objective-C. Note that this
// file is copied into and compiled with the generated
// bindings.
/*
#cgo CFLAGS: -x objective-c -fobjc-arc -fmodules -fblocks -Werror
#cgo LDFLAGS: -framework Foundation
#include <stdint.h>
#include <stdlib.h>
#include "seq.h"
*/
import "C"
import (
"unsafe"
"golang.org/x/mobile/bind/seq"
)
// DestroyRef is called by Objective-C to inform Go it is done with a reference.
//export DestroyRef
func DestroyRef(refnum C.int32_t) {
seq.Delete(int32(refnum))
}
// encodeString copies a Go string and returns it as a nstring.
func encodeString(s string) C.nstring {
n := C.int(len(s))
if n == 0 {
return C.nstring{}
}
ptr := C.malloc(C.size_t(n))
if ptr == nil {
panic("encodeString: malloc failed")
}
copy((*[1<<31 - 1]byte)(ptr)[:n], s)
return C.nstring{ptr: ptr, len: n}
}
// decodeString converts a nstring to a Go string. The
// data in str is freed after use.
func decodeString(str C.nstring) string {
if str.ptr == nil {
return ""
}
s := C.GoStringN((*C.char)(str.ptr), str.len)
C.free(str.ptr)
return s
}
// fromSlice converts a slice to a nbyteslice.
// If cpy is set, a malloc'ed copy of the data is returned.
func fromSlice(s []byte, cpy bool) C.nbyteslice {
if s == nil || len(s) == 0 {
return C.nbyteslice{}
}
ptr, n := unsafe.Pointer(&s[0]), C.int(len(s))
if cpy {
nptr := C.malloc(C.size_t(n))
if nptr == nil {
panic("fromSlice: malloc failed")
}
copy((*[1<<31 - 1]byte)(nptr)[:n], (*[1<<31 - 1]byte)(ptr)[:n])
ptr = nptr
}
return C.nbyteslice{ptr: ptr, len: n}
}
// toSlice takes a nbyteslice and returns a byte slice with the data. If cpy is
// set, the slice contains a copy of the data. If not, the generated Go code
// calls releaseByteSlice after use.
func toSlice(s C.nbyteslice, cpy bool) []byte {
if s.ptr == nil || s.len == 0 {
return nil
}
var b []byte
if cpy {
b = C.GoBytes(s.ptr, C.int(s.len))
C.free(s.ptr)
} else {
b = (*[1<<31 - 1]byte)(unsafe.Pointer(s.ptr))[:s.len:s.len]
}
return b
}