1 /* go-make-slice.c -- make a slice.
2
3 Copyright 2011 The Go Authors. All rights reserved.
4 Use of this source code is governed by a BSD-style
5 license that can be found in the LICENSE file. */
6
7 #include <stdint.h>
8
9 #include "runtime.h"
10 #include "go-alloc.h"
11 #include "go-assert.h"
12 #include "go-panic.h"
13 #include "go-type.h"
14 #include "array.h"
15 #include "arch.h"
16 #include "malloc.h"
17
18 /* Dummy word to use as base pointer for make([]T, 0).
19 Since you cannot take the address of such a slice,
20 you can't tell that they all have the same base pointer. */
21 uintptr runtime_zerobase;
22
23 struct __go_open_array
__go_make_slice2(const struct __go_type_descriptor * td,uintptr_t len,uintptr_t cap)24 __go_make_slice2 (const struct __go_type_descriptor *td, uintptr_t len,
25 uintptr_t cap)
26 {
27 const struct __go_slice_type* std;
28 intgo ilen;
29 intgo icap;
30 uintptr_t size;
31 struct __go_open_array ret;
32
33 __go_assert ((td->__code & GO_CODE_MASK) == GO_SLICE);
34 std = (const struct __go_slice_type *) td;
35
36 ilen = (intgo) len;
37 if (ilen < 0
38 || (uintptr_t) ilen != len
39 || (std->__element_type->__size > 0
40 && len > MaxMem / std->__element_type->__size))
41 runtime_panicstring ("makeslice: len out of range");
42
43 icap = (intgo) cap;
44 if (cap < len
45 || (uintptr_t) icap != cap
46 || (std->__element_type->__size > 0
47 && cap > MaxMem / std->__element_type->__size))
48 runtime_panicstring ("makeslice: cap out of range");
49
50 ret.__count = ilen;
51 ret.__capacity = icap;
52
53 size = cap * std->__element_type->__size;
54
55 if (size == 0)
56 ret.__values = &runtime_zerobase;
57 else if ((std->__element_type->__code & GO_NO_POINTERS) != 0)
58 ret.__values =
59 runtime_mallocgc (size,
60 (uintptr) std->__element_type | TypeInfo_Array,
61 FlagNoScan);
62 else
63 ret.__values =
64 runtime_mallocgc (size,
65 (uintptr) std->__element_type | TypeInfo_Array,
66 0);
67
68 return ret;
69 }
70
71 struct __go_open_array
__go_make_slice1(const struct __go_type_descriptor * td,uintptr_t len)72 __go_make_slice1 (const struct __go_type_descriptor *td, uintptr_t len)
73 {
74 return __go_make_slice2 (td, len, len);
75 }
76
77 struct __go_open_array
__go_make_slice2_big(const struct __go_type_descriptor * td,uint64_t len,uint64_t cap)78 __go_make_slice2_big (const struct __go_type_descriptor *td, uint64_t len,
79 uint64_t cap)
80 {
81 uintptr_t slen;
82 uintptr_t scap;
83
84 slen = (uintptr_t) len;
85 if ((uint64_t) slen != len)
86 runtime_panicstring ("makeslice: len out of range");
87
88 scap = (uintptr_t) cap;
89 if ((uint64_t) scap != cap)
90 runtime_panicstring ("makeslice: cap out of range");
91
92 return __go_make_slice2 (td, slen, scap);
93 }
94
95 struct __go_open_array
__go_make_slice1_big(const struct __go_type_descriptor * td,uint64_t len)96 __go_make_slice1_big (const struct __go_type_descriptor *td, uint64_t len)
97 {
98 return __go_make_slice2_big (td, len, len);
99 }
100