2  * Copyright 2021-2022 The OpenSSL Project Authors. All Rights Reserved.
11 # define OSSL_INTERNAL_SAFE_MATH_H
18 #   define has(func) __has_builtin(func)
21 #    define has(func) 1
27 #  define has(func) 0
34 #  define OSSL_SAFE_MATH_ADDS(type_name, type, min, max) \  argument
44         return a < 0 ? min : max;                                            \
47 #  define OSSL_SAFE_MATH_ADDU(type_name, type, max) \  argument
61 #  define OSSL_SAFE_MATH_ADDS(type_name, type, min, max) \  argument
67                 || (a > 0 && b <= max - a)                                   \
68                 || (a < 0 && b >= min - a)                                   \
72         return a < 0 ? min : max;                                            \
75 #  define OSSL_SAFE_MATH_ADDU(type_name, type, max) \  argument
80         if (b > max - a)                                                     \
90 #  define OSSL_SAFE_MATH_SUBS(type_name, type, min, max) \  argument
100         return a < 0 ? min : max;                                            \
104 #  define OSSL_SAFE_MATH_SUBS(type_name, type, min, max) \  argument
111                 || (b < 0 && a <= max + b)                                   \
113             return a - b;                                                    \
115         return a < 0 ? min : max;                                            \
120 # define OSSL_SAFE_MATH_SUBU(type_name, type) \
127         return a - b;                                                        \
134 #  define OSSL_SAFE_MATH_MULS(type_name, type, min, max) \  argument
144         return (a < 0) ^ (b < 0) ? min : max;                                \
147 #  define OSSL_SAFE_MATH_MULU(type_name, type, max) \  argument
161 #  define OSSL_SAFE_MATH_MULS(type_name, type, min, max) \  argument
173             const type x = a < 0 ? -a : a;                                   \
174             const type y = b < 0 ? -b : b;                                   \
176             if (x <= max / y)                                                \
180         return (a < 0) ^ (b < 0) ? min : max;                                \
183 #  define OSSL_SAFE_MATH_MULU(type_name, type, max) \  argument
188         if (b != 0 && a > max / b)                                           \
197 # define OSSL_SAFE_MATH_DIVS(type_name, type, min, max) \  argument
204             return a < 0 ? min : max;                                        \
206         if (b == -1 && a == min) {                                           \
208             return max;                                                      \
213 # define OSSL_SAFE_MATH_DIVU(type_name, type, max) \  argument
221         return max;                                                        \
227 # define OSSL_SAFE_MATH_MODS(type_name, type, min, max) \  argument
236         if (b == -1 && a == min) {                                           \
238             return max;                                                      \
243 # define OSSL_SAFE_MATH_MODU(type_name, type) \
257 # define OSSL_SAFE_MATH_NEGS(type_name, type, min) \
262             return -a;                                                       \
267 # define OSSL_SAFE_MATH_NEGU(type_name, type) \
280 # define OSSL_SAFE_MATH_ABSS(type_name, type, min) \
285             return a < 0 ? -a : a;                                           \
290 # define OSSL_SAFE_MATH_ABSU(type_name, type) \
301  *    . They begin by checking the denominator for zero and getting rid of this
319 # define OSSL_SAFE_MATH_MULDIVS(type_name, type, max) \  argument
330             return a == 0 || b == 0 ? 0 : max;                               \
348 # define OSSL_SAFE_MATH_MULDIVU(type_name, type, max) \  argument
359             return a == 0 || b == 0 ? 0 : max;                               \
377  * Which is usually (less safely) converted to (a + b - 1) / b
380 #define OSSL_SAFE_MATH_DIV_ROUND_UP(type_name, type, max) \  argument
387         /* Allow errors to be ignored by callers */                          \
392             if (a < max - b)                                                 \
393                 return (a + b - 1) / b;                                      \
398             return a == 0 ? 0 : max;                                         \
409 # define OSSL_SAFE_MATH_MINS(type) ((type)1 << (sizeof(type) * 8 - 1))
410 # define OSSL_SAFE_MATH_MAXS(type) (~OSSL_SAFE_MATH_MINS(type))
411 # define OSSL_SAFE_MATH_MAXU(type) (~(type)0)
416 # define OSSL_SAFE_MATH_SIGNED(type_name, type)                         \
433 # define OSSL_SAFE_MATH_UNSIGNED(type_name, type) \