1 /*
2 * duk_hbuffer allocation and freeing.
3 */
4
5 #include "duk_internal.h"
6
7 /* Allocate a new duk_hbuffer of a certain type and return a pointer to it
8 * (NULL on error). Write buffer data pointer to 'out_bufdata' (only if
9 * allocation successful).
10 */
duk_hbuffer_alloc(duk_heap * heap,duk_size_t size,duk_small_uint_t flags,void ** out_bufdata)11 DUK_INTERNAL duk_hbuffer *duk_hbuffer_alloc(duk_heap *heap, duk_size_t size, duk_small_uint_t flags, void **out_bufdata) {
12 duk_hbuffer *res = NULL;
13 duk_size_t header_size;
14 duk_size_t alloc_size;
15
16 DUK_ASSERT(heap != NULL);
17 DUK_ASSERT(out_bufdata != NULL);
18
19 DUK_DDD(DUK_DDDPRINT("allocate hbuffer"));
20
21 /* Size sanity check. Should not be necessary because caller is
22 * required to check this, but we don't want to cause a segfault
23 * if the size wraps either in duk_size_t computation or when
24 * storing the size in a 16-bit field.
25 */
26 if (size > DUK_HBUFFER_MAX_BYTELEN) {
27 DUK_D(DUK_DPRINT("hbuffer alloc failed: size too large: %ld", (long) size));
28 return NULL; /* no need to write 'out_bufdata' */
29 }
30
31 if (flags & DUK_BUF_FLAG_EXTERNAL) {
32 header_size = sizeof(duk_hbuffer_external);
33 alloc_size = sizeof(duk_hbuffer_external);
34 } else if (flags & DUK_BUF_FLAG_DYNAMIC) {
35 header_size = sizeof(duk_hbuffer_dynamic);
36 alloc_size = sizeof(duk_hbuffer_dynamic);
37 } else {
38 header_size = sizeof(duk_hbuffer_fixed);
39 alloc_size = sizeof(duk_hbuffer_fixed) + size;
40 DUK_ASSERT(alloc_size >= sizeof(duk_hbuffer_fixed)); /* no wrapping */
41 }
42
43 res = (duk_hbuffer *) DUK_ALLOC(heap, alloc_size);
44 if (!res) {
45 goto error;
46 }
47
48 /* zero everything unless requested not to do so */
49 #if defined(DUK_USE_ZERO_BUFFER_DATA)
50 DUK_MEMZERO((void *) res,
51 (flags & DUK_BUF_FLAG_NOZERO) ? header_size : alloc_size);
52 #else
53 DUK_MEMZERO((void *) res, header_size);
54 #endif
55
56 if (flags & DUK_BUF_FLAG_EXTERNAL) {
57 duk_hbuffer_external *h;
58 h = (duk_hbuffer_external *) res;
59 DUK_UNREF(h);
60 *out_bufdata = NULL;
61 #if defined(DUK_USE_EXPLICIT_NULL_INIT)
62 #if defined(DUK_USE_HEAPPTR16)
63 /* the compressed pointer is zeroed which maps to NULL, so nothing to do. */
64 #else
65 DUK_HBUFFER_EXTERNAL_SET_DATA_PTR(heap, h, NULL);
66 #endif
67 #endif
68 DUK_ASSERT(DUK_HBUFFER_EXTERNAL_GET_DATA_PTR(heap, h) == NULL);
69 } else if (flags & DUK_BUF_FLAG_DYNAMIC) {
70 duk_hbuffer_dynamic *h = (duk_hbuffer_dynamic *) res;
71 void *ptr;
72
73 if (size > 0) {
74 DUK_ASSERT(!(flags & DUK_BUF_FLAG_EXTERNAL)); /* alloc external with size zero */
75 DUK_DDD(DUK_DDDPRINT("dynamic buffer with nonzero size, alloc actual buffer"));
76 #ifdef DUK_USE_ZERO_BUFFER_DATA
77 ptr = DUK_ALLOC_ZEROED(heap, size);
78 #else
79 ptr = DUK_ALLOC(heap, size);
80 #endif
81 if (!ptr) {
82 /* Because size > 0, NULL check is correct */
83 goto error;
84 }
85 *out_bufdata = ptr;
86
87 DUK_HBUFFER_DYNAMIC_SET_DATA_PTR(heap, h, ptr);
88 } else {
89 *out_bufdata = NULL;
90 #if defined(DUK_USE_EXPLICIT_NULL_INIT)
91 #if defined(DUK_USE_HEAPPTR16)
92 /* the compressed pointer is zeroed which maps to NULL, so nothing to do. */
93 #else
94 DUK_HBUFFER_DYNAMIC_SET_DATA_PTR(heap, h, NULL);
95 #endif
96 #endif
97 DUK_ASSERT(DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap, h) == NULL);
98 }
99 } else {
100 *out_bufdata = (void *) ((duk_hbuffer_fixed *) res + 1);
101 }
102
103 DUK_HBUFFER_SET_SIZE(res, size);
104
105 DUK_HEAPHDR_SET_TYPE(&res->hdr, DUK_HTYPE_BUFFER);
106 if (flags & DUK_BUF_FLAG_DYNAMIC) {
107 DUK_HBUFFER_SET_DYNAMIC(res);
108 if (flags & DUK_BUF_FLAG_EXTERNAL) {
109 DUK_HBUFFER_SET_EXTERNAL(res);
110 }
111 } else {
112 DUK_ASSERT(!(flags & DUK_BUF_FLAG_EXTERNAL));
113 }
114 DUK_HEAP_INSERT_INTO_HEAP_ALLOCATED(heap, &res->hdr);
115
116 DUK_DDD(DUK_DDDPRINT("allocated hbuffer: %p", (void *) res));
117 return res;
118
119 error:
120 DUK_DD(DUK_DDPRINT("hbuffer allocation failed"));
121
122 DUK_FREE(heap, res);
123 return NULL; /* no need to write 'out_bufdata' */
124 }
125
126 /* For indirect allocs. */
127
duk_hbuffer_get_dynalloc_ptr(duk_heap * heap,void * ud)128 DUK_INTERNAL void *duk_hbuffer_get_dynalloc_ptr(duk_heap *heap, void *ud) {
129 duk_hbuffer_dynamic *buf = (duk_hbuffer_dynamic *) ud;
130 DUK_UNREF(heap);
131 return (void *) DUK_HBUFFER_DYNAMIC_GET_DATA_PTR(heap, buf);
132 }
133