/
mbsdcc.h
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/
mbsdcc.h
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/*-
* MirBSD ISO C compiler toolkit (macros for mbsdint.h and others)
*
* © mirabilos Ⓕ CC0 or The MirOS Licence (MirBSD)
*/
#ifndef SYSKERN_MBSDCC_H
#define SYSKERN_MBSDCC_H "$MirOS: src/bin/mksh/mbsdcc.h,v 1.9 2024/04/02 03:16:49 tg Exp $"
/*
* Note: this header uses the SIZE_MAX (or similar) definitions
* from <basetsd.h> or <limits.h> if present, so either include
* these before this header or include "mbsdint.h", which fixes
* up the corresponding definition.
*
* Furthermore, either include <stdlib.h> for abort(3), or pro‐
* vide an mbccABEND macro (preferred).
*/
#if !defined(_KERNEL) && !defined(_STANDALONE)
#include <stddef.h>
#else
#include <sys/stddef.h>
#endif
/* mbccABEND should be provided by the user, called by mbsd*.h only */
#ifndef mbccABEND
#define mbccABEND(reasonstr) abort()
#endif
/* monkey-patch known-bad offsetof versions */
#if (defined(__KLIBC__) || defined(__dietlibc__)) && \
((defined(__GNUC__) && (__GNUC__ > 3)) || defined(__NWCC__))
#undef offsetof
#define offsetof(struc,memb) __builtin_offsetof(struc, memb)
#endif
/* mbsdint.h replaces this with mbiSIZE_MAX */
#undef mbccSIZE_MAX
#if defined(SIZE_MAX)
#define mbccSIZE_MAX ((size_t)(SIZE_MAX)
#elif defined(SIZE_T_MAX)
#define mbccSIZE_MAX ((size_t)(SIZE_T_MAX)
#elif defined(MAXSIZE_T)
#define mbccSIZE_MAX ((size_t)(MAXSIZE_T)
#else
#define mbccSIZE_MAX ((size_t)~(size_t)0)
#endif
#ifdef __cplusplus
#define mbcextern extern "C"
/* for headers (BSD __BEGIN_DECLS/__END_DECLS) */
#define mbcextern_beg extern "C" {
#define mbcextern_end }
#else
#define mbcextern extern
#define mbcextern_beg
#define mbcextern_end
#endif
/* compiler warning pragmas, NOP for other compilers */
#ifdef _MSC_VER
/* push, suppress space-separated listed warning numbers */
#define mbmscWd(d) __pragma(warning(push)) \
__pragma(warning(disable: d))
/* suppress for only the next line */
#define mbmscWs(d) __pragma(warning(suppress: d))
/* pop from mbmscWd */
#define mbmscWpop __pragma(warning(pop))
#else
#define mbmscWd(d)
#define mbmscWs(d)
#define mbmscWpop
#endif
/* in-expression compile-time check evaluating to 0 */
#ifdef __cplusplus
template<bool> struct mbccChkExpr_sa;
template<> struct mbccChkExpr_sa<true> { typedef int Type; };
#define mbccChkExpr(test) (static_cast<mbccChkExpr_sa<!!(0+(test))>::Type>(0))
#else
#define mbccChkExpr(test) mbmscWs(4116) \
(sizeof(struct { unsigned int (mbccChkExpr):((0+(test)) ? 1 : -1); }) * 0)
#endif
/* ensure value x is a constant expression */
#ifdef __cplusplus
template<bool,bool> struct mbccCEX_sa;
template<> struct mbccCEX_sa<true,false> { typedef int Type; };
template<> struct mbccCEX_sa<false,true> { typedef int Type; };
#define mbccCEX(x) (static_cast<mbccCEX_sa<!!(0+(x)), !(0+(x))>::Type>(0) + (x))
#else
#define mbccCEX(x) mbmscWs(4116) \
(sizeof(struct { unsigned int (mbccCEX):(((0+(x)) && 1) + 1); }) * 0 + (x))
#endif
/* flexible array member */
#if defined(__cplusplus)
#ifdef __cpp_flexible_array_members
#define mbccFAMslot(type,memb) type memb[]
#elif defined(__GNUC__) || defined(__clang__) || defined(_MSC_VER)
#define mbccFAMslot(type,memb) type memb[0] mbmscWs(4200 4820)
#else
#define mbccFAMslot(type,memb) type memb[1] mbmscWs(4820)
#endif
#elif (defined(__STDC_VERSION__) && ((__STDC_VERSION__) >= 199901L))
#define mbccFAMslot(type,memb) type memb[]
#elif defined(__GNUC__)
#define mbccFAMslot(type,memb) type memb[0] mbmscWs(4200 4820)
#else
#define mbccFAMslot(type,memb) type memb[1] mbmscWs(4820) /* SOL */
#endif
#define mbccFAMsz_i(t,memb,sz) /*private*/ (size_t)(offsetof(t, memb) + (size_t)sz)
/* compile-time constant */
#define mbccFAMSZ(struc,memb,sz) ((size_t)( \
mbccChkExpr(mbccSIZE_MAX - sizeof(struc) > mbccCEX((size_t)(sz))) + \
(mbccFAMsz_i(struc, memb, (sz)) > sizeof(struc) ? \
mbccFAMsz_i(struc, memb, (sz)) : sizeof(struc))))
/* run-time */
#define mbccFAMsz(struc,memb,sz) ((size_t)( \
!(mbccSIZE_MAX - sizeof(struc) > (size_t)(sz)) ? \
(mbccABEND("mbccFAMsz: " mbccS(sz) " too large for " mbccS(struc) "." mbccS(memb)), 0) : \
(mbccFAMsz_i(struc, memb, (sz)) > sizeof(struc) ? \
mbccFAMsz_i(struc, memb, (sz)) : sizeof(struc))))
/* example:
*
* struct s {
* int type;
* mbccFAMslot(char, label); // like char label[…];
* };
* struct t {
* int count;
* mbccFAMslot(time_t, value);
* };
* union fixed_s {
* struct s s;
* char storage[mbccFAMSZ(struct s, label, 28)];
* };
* struct s *sp = malloc(mbccFAMsz(struct s, label, strlen(labelvar) + 1U));
* struct t *tp = malloc(mbccFAMsz(struct t, value, sizeof(time_t[cnt])));
* tp->count = cnt;
* struct s *np = malloc(mbccFAMSZ(struct s, label, sizeof("myname")));
* memcpy(np->label, "myname", sizeof("myname"));
* static union fixed_s preallocated;
* preallocated.s.label[0] = '\0';
* somefunc((struct s *)&preallocated);
*/
/* field sizeof */
#if defined(__cplusplus)
/* TODO: add better way on CFrustFrust once it has one */
#define mbccFSZ(struc,memb) (sizeof(((struc *)0)->memb))
#elif (defined(__STDC_VERSION__) && ((__STDC_VERSION__) >= 199901L))
#define mbccFSZ(struc,memb) (sizeof(((struc){0}).memb))
#else
#define mbccFSZ(struc,memb) (sizeof(((struc *)0)->memb))
#endif
/* stringification with expansion */
#define mbccS(x) #x
#define mbccS2(x) mbccS(x)
/* compile-time assertions */
#undef mbccCTA
#if defined(__WATCOMC__) && !defined(__WATCOM_CPLUSPLUS__)
/* “Comparison result always 0” */
#define mbccCTA_wb _Pragma("warning 124 5")
/*XXX no pop so set to visible info */
#define mbccCTA_we _Pragma("warning 124 4")
#else
#define mbccCTA_wb /* nothing */
#define mbccCTA_we /* nothing */
#endif
#if defined(__cplusplus)
#ifdef __cpp_static_assert
#define mbccCTA(fldn,cond) static_assert(cond, mbccS(fldn))
#endif
#elif (defined(__STDC_VERSION__) && ((__STDC_VERSION__) >= 202311L))
#define mbccCTA(fldn,cond) static_assert(cond, mbccS(fldn))
#elif (defined(__STDC_VERSION__) && ((__STDC_VERSION__) >= 201112L))
#define mbccCTA(fldn,cond) _Static_assert(cond, mbccS(fldn))
#elif defined(__GNUC__) && \
((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6))
#define mbccCTA(fldn,cond) __extension__ _Static_assert(cond, mbccS(fldn))
#endif
#ifndef mbccCTA
/* single assertion for macros (with fldn prefixed, cond parenthesised) */
#define mbccCTA(fldn,cond) unsigned int fldn:(cond ? 1 : -1)
/* begin/end assertion block */
#define mbCTA_BEG(name) struct ctassert_ ## name { mbccCTA_wb \
int _ctabeg /* plus user semicolon */
#define mbCTA_END(name) int _ctaend; \
}; \
struct ctassert2 ## name { \
char t[sizeof(struct ctassert_ ## name) > 1U ? 1 : -1]; \
mbccCTA_we } /* semicolon provided by user */
#else
/* nothing, but syntax-check equally to manual compile-time assert macro */
#define mbCTA_BEG(name) struct ctassert_ ## name { mbccCTA_wb \
char t[2]; \
} /* semicolon provided by user */
#define mbCTA_END(name) struct ctassert2 ## name { \
char t[sizeof(struct ctassert_ ## name) > 1U ? 1 : -1]; \
mbccCTA_we } /* semicolon provided by user */
#endif
/* single assertion */
#define mbCTA(name,cond) mbccCTA(cta_ ## name, (cond))
/* nil pointer constant */
#if (defined(__cplusplus) && (__cplusplus >= 201103L)) || \
(defined(__STDC_VERSION__) && ((__STDC_VERSION__) >= 202311L))
#define mbnil nullptr
#elif defined(__GNUG__)
#define mbnil __null
#elif defined(__cplusplus)
#define mbnil (size_t)0UL /* wtf, why? */
#else
#define mbnil (void *)0UL
#endif
/* præfix to avoid -Wunused-result when it really cannot be helped */
#ifdef _FORTIFY_SOURCE
/* workaround via https://stackoverflow.com/a/64407070/2171120 */
#define SHIKATANAI (void)!
#else
#define SHIKATANAI (void)
#endif
#endif /* !SYSKERN_MBSDCC_H */