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comparison tango/lib/compiler/llvmdc/cast.d @ 132:1700239cab2e trunk

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[svn r136] MAJOR UNSTABLE UPDATE!!! Initial commit after moving to Tango instead of Phobos. Lots of bugfixes... This build is not suitable for most things.
author lindquist
date Fri, 11 Jan 2008 17:57:40 +0100
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children 44a95ac7368a
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131:5825d48b27d1 132:1700239cab2e
1 /*
2 * Copyright (C) 2004-2006 by Digital Mars, www.digitalmars.com
3 * Written by Walter Bright
4 *
5 * This software is provided 'as-is', without any express or implied
6 * warranty. In no event will the authors be held liable for any damages
7 * arising from the use of this software.
8 *
9 * Permission is granted to anyone to use this software for any purpose,
10 * including commercial applications, and to alter it and redistribute it
11 * freely, in both source and binary form, subject to the following
12 * restrictions:
13 *
14 * o The origin of this software must not be misrepresented; you must not
15 * claim that you wrote the original software. If you use this software
16 * in a product, an acknowledgment in the product documentation would be
17 * appreciated but is not required.
18 * o Altered source versions must be plainly marked as such, and must not
19 * be misrepresented as being the original software.
20 * o This notice may not be removed or altered from any source
21 * distribution.
22 */
23
24 /*
25 * Modified by Sean Kelly <sean@f4.ca> for use with Tango.
26 */
27
28 extern (C):
29
30 /******************************************
31 * Given a pointer:
32 * If it is an Object, return that Object.
33 * If it is an interface, return the Object implementing the interface.
34 * If it is null, return null.
35 * Else, undefined crash
36 */
37
38 Object _d_toObject(void* p)
39 { Object o;
40
41 if (p)
42 {
43 o = cast(Object)p;
44 ClassInfo oc = o.classinfo;
45 Interface *pi = **cast(Interface ***)p;
46
47 /* Interface.offset lines up with ClassInfo.name.ptr,
48 * so we rely on pointers never being less than 64K,
49 * and Objects never being greater.
50 */
51 if (pi.offset < 0x10000)
52 {
53 //printf("\tpi.offset = %d\n", pi.offset);
54 o = cast(Object)(p - pi.offset);
55 }
56 }
57 return o;
58 }
59
60
61 /*************************************
62 * Attempts to cast Object o to class c.
63 * Returns o if successful, null if not.
64 */
65
66 Object _d_interface_cast(void* p, ClassInfo c)
67 { Object o;
68
69 //printf("_d_interface_cast(p = %p, c = '%.*s')\n", p, c.name);
70 if (p)
71 {
72 Interface *pi = **cast(Interface ***)p;
73
74 //printf("\tpi.offset = %d\n", pi.offset);
75 o = cast(Object)(p - pi.offset);
76 return _d_dynamic_cast(o, c);
77 }
78 return o;
79 }
80
81 Object _d_dynamic_cast(Object o, ClassInfo c)
82 { ClassInfo oc;
83 size_t offset = 0;
84
85 //printf("_d_dynamic_cast(o = %p, c = '%.*s')\n", o, c.name);
86
87 if (o)
88 {
89 oc = o.classinfo;
90 if (_d_isbaseof2(oc, c, offset))
91 {
92 //printf("\toffset = %d\n", offset);
93 o = cast(Object)(cast(void*)o + offset);
94 }
95 else
96 o = null;
97 }
98 //printf("\tresult = %p\n", o);
99 return o;
100 }
101
102 int _d_isbaseof2(ClassInfo oc, ClassInfo c, inout size_t offset)
103 { int i;
104
105 if (oc is c)
106 return 1;
107 do
108 {
109 if (oc.base is c)
110 return 1;
111 for (i = 0; i < oc.interfaces.length; i++)
112 {
113 ClassInfo ic;
114
115 ic = oc.interfaces[i].classinfo;
116 if (ic is c)
117 { offset = cast(size_t)oc.interfaces[i].offset;
118 return 1;
119 }
120 }
121 for (i = 0; i < oc.interfaces.length; i++)
122 {
123 ClassInfo ic;
124
125 ic = oc.interfaces[i].classinfo;
126 if (_d_isbaseof2(ic, c, offset))
127 { offset = cast(size_t)oc.interfaces[i].offset;
128 return 1;
129 }
130 }
131 oc = oc.base;
132 } while (oc);
133 return 0;
134 }
135
136 int _d_isbaseof(ClassInfo oc, ClassInfo c)
137 { int i;
138
139 if (oc is c)
140 return 1;
141 do
142 {
143 if (oc.base is c)
144 return 1;
145 for (i = 0; i < oc.interfaces.length; i++)
146 {
147 ClassInfo ic;
148
149 ic = oc.interfaces[i].classinfo;
150 if (ic is c || _d_isbaseof(ic, c))
151 return 1;
152 }
153 oc = oc.base;
154 } while (oc);
155 return 0;
156 }
157
158 /*********************************
159 * Find the vtbl[] associated with Interface ic.
160 */
161
162 void *_d_interface_vtbl(ClassInfo ic, Object o)
163 { int i;
164 ClassInfo oc;
165
166 //printf("__d_interface_vtbl(o = %p, ic = %p)\n", o, ic);
167
168 assert(o);
169
170 oc = o.classinfo;
171 for (i = 0; i < oc.interfaces.length; i++)
172 {
173 ClassInfo oic;
174
175 oic = oc.interfaces[i].classinfo;
176 if (oic is ic)
177 {
178 return cast(void *)oc.interfaces[i].vtbl;
179 }
180 }
181 assert(0);
182 }