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comparison druntime/src/compiler/dmd/arraycast.d @ 1458:e0b2d67cfe7c

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Added druntime (this should be removed once it works).
author Robert Clipsham <robert@octarineparrot.com>
date Tue, 02 Jun 2009 17:43:06 +0100
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1456:7b218ec1044f 1458:e0b2d67cfe7c
1 /**
2 * Implementation of array cast support routines.
3 *
4 * Copyright: Copyright Digital Mars 2004 - 2009.
5 * License: <a href="http://www.boost.org/LICENSE_1_0.txt>Boost License 1.0</a>.
6 * Authors: Walter Bright, Sean Kelly
7 *
8 * Copyright Digital Mars 2004 - 2009.
9 * Distributed under the Boost Software License, Version 1.0.
10 * (See accompanying file LICENSE_1_0.txt or copy at
11 * http://www.boost.org/LICENSE_1_0.txt)
12 */
13 module rt.arraycast;
14
15 /******************************************
16 * Runtime helper to convert dynamic array of one
17 * type to dynamic array of another.
18 * Adjusts the length of the array.
19 * Throws exception if new length is not aligned.
20 */
21
22 extern (C)
23
24 void[] _d_arraycast(size_t tsize, size_t fsize, void[] a)
25 {
26 auto length = a.length;
27
28 auto nbytes = length * fsize;
29 if (nbytes % tsize != 0)
30 {
31 throw new Exception("array cast misalignment");
32 }
33 length = nbytes / tsize;
34 *cast(size_t *)&a = length; // jam new length
35 return a;
36 }
37
38 unittest
39 {
40 byte[int.sizeof * 3] b;
41 int[] i;
42 short[] s;
43
44 i = cast(int[])b;
45 assert(i.length == 3);
46
47 s = cast(short[])b;
48 assert(s.length == 6);
49
50 s = cast(short[])i;
51 assert(s.length == 6);
52 }
53
54 /******************************************
55 * Runtime helper to convert dynamic array of bits
56 * dynamic array of another.
57 * Adjusts the length of the array.
58 * Throws exception if new length is not aligned.
59 */
60
61 version (none)
62 {
63 extern (C)
64
65 void[] _d_arraycast_frombit(uint tsize, void[] a)
66 {
67 uint length = a.length;
68
69 if (length & 7)
70 {
71 throw new Exception("bit[] array cast misalignment");
72 }
73 length /= 8 * tsize;
74 *cast(size_t *)&a = length; // jam new length
75 return a;
76 }
77
78 unittest
79 {
80 version (D_Bits)
81 {
82 bit[int.sizeof * 3 * 8] b;
83 int[] i;
84 short[] s;
85
86 i = cast(int[])b;
87 assert(i.length == 3);
88
89 s = cast(short[])b;
90 assert(s.length == 6);
91 }
92 }
93
94 }