mirror of https://github.com/ctm/syn68k.git
56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
#if !defined(__safe_alloca__)
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#define __safe_alloca__
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#include <assert.h>
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#if !defined(NDEBUG)
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#define FIREWALL_START 0x940504FE
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#define FIREWALL_STOP_0 0xEE
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#define FIREWALL_STOP_1 0x41
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#define FIREWALL_STOP_2 0x51
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#define FIREWALL_STOP_3 0x59
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/*
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* I don't like this implementation, but it works.
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*/
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#define SAFE_DECL() \
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unsigned long ___newsize; \
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unsigned char *___tempptr
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#define SAFE_alloca(size) \
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( \
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___newsize = (size) + 3 * sizeof(long), \
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___tempptr = alloca(___newsize), \
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((long *)___tempptr)[0] = ___newsize, \
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((long *)___tempptr)[1] = FIREWALL_START, \
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___tempptr[___newsize-4] = FIREWALL_STOP_0, \
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___tempptr[___newsize-3] = FIREWALL_STOP_1, \
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___tempptr[___newsize-2] = FIREWALL_STOP_2, \
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___tempptr[___newsize-1] = FIREWALL_STOP_3, \
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(void *) (___tempptr + 2 * sizeof(long)) \
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)
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#define ASSERT_SAFE(var) \
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do { \
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___tempptr = (unsigned char *) (var); \
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___tempptr -= 2 * sizeof(long); \
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assert(((long *)___tempptr)[1] == FIREWALL_START); \
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___newsize = ((long *)___tempptr)[0]; \
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assert(___tempptr[___newsize-4] == FIREWALL_STOP_0); \
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assert(___tempptr[___newsize-3] == FIREWALL_STOP_1); \
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assert(___tempptr[___newsize-2] == FIREWALL_STOP_2); \
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assert(___tempptr[___newsize-1] == FIREWALL_STOP_3); \
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} while (0)
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#else /* defined(NDEBUG) */
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#define SAFE_DECL() unsigned long ___newsize
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#define SAFE_alloca(size) alloca(size)
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#define ASSERT_SAFE(var) do {} while (0)
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#endif /* defined(NDEBUG) */
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#endif /* !defined(__safe_alloca__) */
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