Commit 5a34472d authored by James Bardin's avatar James Bardin Committed by Ian Lance Taylor

cmd/cgo: add C.CBytes

Add a C.CBytes function to copy a Go byte slice into C memory. This
returns an unsafe.Pointer, since that is what needs to be passed to
C.free, and the data is often opaque bytes anyway.

Fixes #14838

Change-Id: Ic7bc29637eb6f1f5ee409b3898c702a59833a85a
Reviewed-on: https://go-review.googlesource.com/20762Reviewed-by: default avatarIan Lance Taylor <iant@golang.org>
parent 3e54ca9a
......@@ -69,5 +69,6 @@ func Test11925(t *testing.T) { test11925(t) }
func Test12030(t *testing.T) { test12030(t) }
func TestGCC68255(t *testing.T) { testGCC68255(t) }
func TestCallGoWithString(t *testing.T) { testCallGoWithString(t) }
func Test14838(t *testing.T) { test14838(t) }
func BenchmarkCgoCall(b *testing.B) { benchCgoCall(b) }
// 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.
// Issue 14838. add CBytes function
package cgotest
/*
#include <stdlib.h>
int check_cbytes(char *b, size_t l) {
int i;
for (i = 0; i < l; i++) {
if (b[i] != i) {
return 0;
}
}
return 1;
}
*/
import "C"
import (
"testing"
"unsafe"
)
func test14838(t *testing.T) {
data := []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
cData := C.CBytes(data)
defer C.free(cData)
if C.check_cbytes((*C.char)(cData), C.size_t(len(data))) == 0 {
t.Fatalf("mismatched data: expected %v, got %v", data, (*(*[10]byte)(unsafe.Pointer(cData)))[:])
}
}
......@@ -198,6 +198,13 @@ by making copies of the data. In pseudo-Go definitions:
// if C.free is needed).
func C.CString(string) *C.char
// Go []byte slice to C array
// The C array is allocated in the C heap using malloc.
// It is the caller's responsibility to arrange for it to be
// freed, such as by calling C.free (be sure to include stdlib.h
// if C.free is needed).
func C.CBytes([]byte) unsafe.Pointer
// C string to Go string
func C.GoString(*C.char) string
......
......@@ -533,6 +533,7 @@ func fixGo(name string) string {
var isBuiltin = map[string]bool{
"_Cfunc_CString": true,
"_Cfunc_CBytes": true,
"_Cfunc_GoString": true,
"_Cfunc_GoStringN": true,
"_Cfunc_GoBytes": true,
......@@ -1324,6 +1325,7 @@ _GoString_ GoString(char *p);
_GoString_ GoStringN(char *p, int l);
_GoBytes_ GoBytes(void *p, int n);
char *CString(_GoString_);
void *CBytes(_GoBytes_);
void *_CMalloc(size_t);
`
......@@ -1389,6 +1391,15 @@ func _Cfunc_CString(s string) *_Ctype_char {
}
`
const cBytesDef = `
func _Cfunc_CBytes(b []byte) unsafe.Pointer {
p := _cgo_runtime_cmalloc(uintptr(len(b)))
pp := (*[1<<30]byte)(p)
copy(pp[:], b)
return p
}
`
const cMallocDef = `
func _Cfunc__CMalloc(n _Ctype_size_t) unsafe.Pointer {
return _cgo_runtime_cmalloc(uintptr(n))
......@@ -1400,6 +1411,7 @@ var builtinDefs = map[string]string{
"GoStringN": goStringNDef,
"GoBytes": goBytesDef,
"CString": cStringDef,
"CBytes": cBytesDef,
"_CMalloc": cMallocDef,
}
......@@ -1437,6 +1449,12 @@ const char *_cgoPREFIX_Cfunc_CString(struct __go_string s) {
return p;
}
void *_cgoPREFIX_Cfunc_CBytes(struct __go_open_array b) {
char *p = malloc(b.__count);
memmove(p, b.__data, b.__count);
return p;
}
struct __go_string _cgoPREFIX_Cfunc_GoString(char *p) {
intgo len = (p != NULL) ? strlen(p) : 0;
return __go_byte_array_to_string(p, len);
......
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