9883652f96
Add a header-only library for C23 checked integer arithmetic from https://github.com/jart/jtckdint Use it in the ftypes handling instead of the implementations in safe-math. Note that the return value is opposite (true means overflow occurred). C23 stdckdint.h (and jtckdint.h) do not include implementations for div, mod, and unary negation, where division by zero and, for signed integers, cases like INT_MIN / -1 which overflow from INT_MAX + 1 for 2's complement. Those cases have to be handled separately. Note that the divide by zero case, unlike the others, can't really have a "this is what the answer is if you just want the result to wrap around," though that doesn't matter for the ftypes/dfilter. Ping #20144
23 lines
719 B
C
23 lines
719 B
C
/* Overflow-safe math helper macros
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*
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* To the extent possible under law, the authors have waived all
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* copyright and related or neighboring rights to this code. For
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* details, see the Creative Commons Zero 1.0 Universal license at
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* https://creativecommons.org/publicdomain/zero/1.0/
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*/
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#pragma once
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#include <setjmp.h>
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#define ws_safe_op_jmp(op, res, a, b, env) \
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do { \
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if(ckd_##op(res, a, b)) { \
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longjmp(env, 1); \
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} \
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} while (0)
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#define ws_safe_add_jmp(res, a, b, env) ws_safe_op_jmp(add, res, a, b, env)
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#define ws_safe_sub_jmp(res, a, b, env) ws_safe_op_jmp(sub, res, a, b, env)
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#define ws_safe_mul_jmp(res, a, b, env) ws_safe_op_jmp(mul, res, a, b, env)
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