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134 lines
4.2 KiB
C
134 lines
4.2 KiB
C
/* impl.h.misc: MISCELLANEOUS DEFINITIONS
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*
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* $HopeName: MMsrc!misc.h(trunk.16) $
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* Copyright (C) 1997 The Harlequin Group Limited. All rights reserved.
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*
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* Small general things which are useful for C but aren't part of the
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* memory manager itself. The only reason that this file exists is
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* that these things are too small and trivial to be put in their own
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* headers. If they ever become non-trivial they should be moved out.
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*/
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#ifndef misc_h
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#define misc_h
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#include <stddef.h>
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/* offsetof -- offset of field within structure
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*
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* .hack.offsetof: On platform.sus8lc the offsetof macro is not defined
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* (because LCC does not bother fixing up SunOS's broken header files).
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* We define it here using normal C constructs. This hack is only
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* required on platform.sus8lc and no other platforms. See
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* change.mps.tracer2.170226
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*/
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#ifdef MPS_PF_SUS8LC
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#ifdef offsetof
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#error "offsetof was unexpectedly already defined on platform SUS8LC"
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#else
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#define offsetof(type, field) ((size_t)(((char *)&((type *)0)->field) \
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- (char *)0))
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#endif /* offsetof */
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#endif /* MPS_PF_SUS8LC */
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/* SrcId -- source identification
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*
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* Every C source file should start with a SRCID declaration to
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* create a local static source identification structure. This
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* is used by other macros (particularly assertions) and can be
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* used to reverse engineer binary deliverables.
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*/
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typedef const struct SrcIdStruct *SrcId;
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typedef const struct SrcIdStruct {
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const char *file;
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const char *hopename;
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const char *build_date;
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const char *build_time;
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} SrcIdStruct;
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#define SRCID(id, hopename) \
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static SrcIdStruct FileSrcIdStruct = \
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{__FILE__, hopename, __DATE__, __TIME__}; \
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SrcId id ## SrcId = &FileSrcIdStruct
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/* BEGIN and END -- statement brackets
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*
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* BEGIN and END can be used to bracket multi-statement blocks which
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* will be followed by a semicolon, such as multi-statement macros.
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* BEGIN and END should be used to bracket ALL multi-statement macros.
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* The block, with its semicolon, still counts as a single statement.
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* This ensures that such macros can be used in all statement contexts,
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* including in the first branch of an if() statement which has an else
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* clause.
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*/
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#define BEGIN do {
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#define END } while(0)
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/* NOOP -- null statement
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*
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* Do not be tempted to use NULL, or just semicolon as the null
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* statement. These items are dangerously ambigous and could cause
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* subtle bugs if misplaced. NOOP is a macro which is guaranteed to
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* cause an error if it is not used in a statement context.
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*/
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#define NOOP do {} while(0)
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/* UNUSED -- declare parameter unused
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*
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* This macro supresses warnings about unused parameters. It should be
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* applied to the parameter at the beginning of the body of the
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* procedure.
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*
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* The cast to void appears to work for GCC, MSVC, and CodeWarrior.
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* It's a shame there's no way to ensure that the parameter won't be
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* used. We could scramble it, but that's undesirable in release
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* versions.
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*/
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#define UNUSED(param) ((void)param)
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/* PARENT -- parent structure
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*
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* Given a pointer to a field of a structure this returns a pointer to
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* the main structure. PARENT(foo_t, x, foo->x) == foo.
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*
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* This macro is thread-safe. design.mps.misc.parent.thread-safe
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*/
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#define PARENT(type, field, p) \
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((type *)((char *)(p) - offsetof(type, field)))
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/* Bit Sets -- sets of integers in [0,N-1].
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*
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* Can be used on any unsigned integral type, ty. These defintions
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* are _syntactic_, hence macroid, hence upper case
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* (guide.c.naming.macro.special).
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*/
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#define BS_EMPTY(ty) ((ty)0)
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#define BS_COMP(s) (~(s))
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#define BS_UNIV(ty) BS_COMP(BS_EMPTY(ty))
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#define BS_SINGLE(ty, i) ((ty)1 << (i))
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#define BS_IS_MEMBER(s, i) (((s) >> (i)) & 1)
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#define BS_UNION(s1, s2) ((s1) | (s2))
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#define BS_ADD(ty, s, i) BS_UNION(s, BS_SINGLE(ty, i))
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#define BS_INTER(s1, s2) ((s1) & (s2))
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#define BS_DIFF(s1, s2) BS_INTER(s1, BS_COMP(s2))
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#define BS_DEL(ty, s, i) BS_DIFF(s, BS_SINGLE(ty, i))
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#define BS_SUPER(s1, s2) (BS_INTER(s1, s2) == s2)
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#define BS_SUB(s1, s2) BS_SUPER(s2, s1)
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#define BS_IS_SINGLE(s) (((s) & ((s)-1)) == 0)
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#endif /* misc_h */
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