1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
// 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 bindings. This file is copied into the
// generated main package and compiled along with the generated binding
// files.
//#cgo CFLAGS: -Werror
//#cgo LDFLAGS: -llog
//#include <jni.h>
//#include <stdint.h>
//#include <stdlib.h>
//#include "seq_android.h"
import "C"
import (
"unsafe"
"golang.org/x/mobile/bind/seq"
)
// DestroyRef is called by Java to inform Go it is done with a reference.
//export DestroyRef
func DestroyRef(refnum C.int32_t) {
seq.Delete(int32(refnum))
}
// encodeString returns a copy of a Go string as a UTF16 encoded nstring.
// The returned data is freed in go_seq_to_java_string.
//
// encodeString uses UTF16 as the intermediate format. Note that UTF8 is an obvious
// alternative, but JNI only supports a C-safe variant of UTF8 (modified UTF8).
func encodeString(s string) C.nstring {
n := C.int(len(s))
if n == 0 {
return C.nstring{}
}
// Allocate enough for the worst case estimate, every character is a surrogate pair
worstCaseLen := 4 * len(s)
utf16buf := C.malloc(C.size_t(worstCaseLen))
if utf16buf == nil {
panic("encodeString: malloc failed")
}
chars := (*[1<<30 - 1]uint16)(unsafe.Pointer(utf16buf))[:worstCaseLen/2 : worstCaseLen/2]
nchars := seq.UTF16Encode(s, chars)
return C.nstring{chars: unsafe.Pointer(utf16buf), len: C.jsize(nchars*2)}
}
// decodeString decodes a UTF8 encoded nstring to a Go string. The data
// in str is freed after use.
func decodeString(str C.nstring) string {
if str.chars == nil {
return ""
}
chars := (*[1<<31 - 1]byte)(str.chars)[:str.len]
s := string(chars)
C.free(str.chars)
return s
}
// fromSlice converts a slice to a jbyteArray cast as a nbyteslice. If cpy
// is set, the returned slice is a copy to be free by go_seq_to_java_bytearray.
func fromSlice(s []byte, cpy bool) C.nbyteslice {
if s == nil || len(s) == 0 {
return C.nbyteslice{}
}
var ptr *C.jbyte
n := C.jsize(len(s))
if cpy {
ptr = (*C.jbyte)(C.malloc(C.size_t(n)))
if ptr == nil {
panic("fromSlice: malloc failed")
}
copy((*[1<<31 - 1]byte)(unsafe.Pointer(ptr))[:n], s)
} else {
ptr = (*C.jbyte)(unsafe.Pointer(&s[0]))
}
return C.nbyteslice{ptr: unsafe.Pointer(ptr), len: n}
}
// toSlice takes a nbyteslice (jbyteArray) and returns a byte slice
// with the data. If cpy is set, the slice contains a copy of the data and is
// freed.
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
}
|
