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130 lines
2.4 KiB
D
130 lines
2.4 KiB
D
/**
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* Contains a bitfield used by the GC.
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*
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* Copyright: Copyright Digital Mars 2005 - 2013.
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* License: $(WEB www.boost.org/LICENSE_1_0.txt, Boost License 1.0).
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* Authors: Walter Bright, David Friedman, Sean Kelly
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*/
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/* Copyright Digital Mars 2005 - 2013.
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*/
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module gc.bits;
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import core.bitop;
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import core.stdc.string;
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import core.stdc.stdlib;
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import core.exception : onOutOfMemoryError;
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struct GCBits
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{
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alias size_t wordtype;
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enum BITS_PER_WORD = (wordtype.sizeof * 8);
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enum BITS_SHIFT = (wordtype.sizeof == 8 ? 6 : 5);
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enum BITS_MASK = (BITS_PER_WORD - 1);
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enum BITS_1 = cast(wordtype)1;
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wordtype* data;
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size_t nbits;
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void Dtor() nothrow
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{
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if (data)
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{
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free(data);
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data = null;
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}
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}
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void alloc(size_t nbits) nothrow
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{
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this.nbits = nbits;
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data = cast(typeof(data[0])*)calloc(nwords, data[0].sizeof);
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if (!data)
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onOutOfMemoryError();
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}
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wordtype test(size_t i) const nothrow
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in
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{
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assert(i < nbits);
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}
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body
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{
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return core.bitop.bt(data, i);
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}
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int set(size_t i) nothrow
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in
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{
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assert(i < nbits);
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}
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body
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{
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return core.bitop.bts(data, i);
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}
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int clear(size_t i) nothrow
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in
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{
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assert(i <= nbits);
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}
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body
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{
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return core.bitop.btr(data, i);
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}
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void zero() nothrow
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{
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memset(data, 0, nwords * wordtype.sizeof);
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}
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void copy(GCBits *f) nothrow
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in
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{
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assert(nwords == f.nwords);
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}
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body
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{
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memcpy(data, f.data, nwords * wordtype.sizeof);
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}
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@property size_t nwords() const pure nothrow
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{
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return (nbits + (BITS_PER_WORD - 1)) >> BITS_SHIFT;
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}
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}
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unittest
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{
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GCBits b;
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b.alloc(786);
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assert(!b.test(123));
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assert(!b.clear(123));
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assert(!b.set(123));
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assert(b.test(123));
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assert(b.clear(123));
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assert(!b.test(123));
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b.set(785);
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b.set(0);
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assert(b.test(785));
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assert(b.test(0));
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b.zero();
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assert(!b.test(785));
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assert(!b.test(0));
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GCBits b2;
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b2.alloc(786);
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b2.set(38);
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b.copy(&b2);
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assert(b.test(38));
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b2.Dtor();
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b.Dtor();
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}
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