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Added a signed int256 formatting function

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This commit is contained in:
Alexandre Paillier
2022-06-06 18:36:20 +02:00
parent 59d8ace99e
commit f99804de08
4 changed files with 87 additions and 0 deletions
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39
src_common/uint128.c
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@@ -245,3 +245,42 @@ bool tostring128(const uint128_t *const number,
reverseString(out, offset);
return true;
}
/**
* Format a uint128_t into a string as a signed integer
*
* @param[in] number the number to format
* @param[in] base the radix used in formatting
* @param[out] out the output buffer
* @param[in] out_length the length of the output buffer
* @return whether the formatting was successful or not
*/
bool tostring128_signed(const uint128_t *const number,
uint32_t base,
char *const out,
uint32_t out_length) {
uint128_t max_unsigned_val;
uint128_t max_signed_val;
uint128_t one_val;
uint128_t two_val;
uint128_t tmp;
// showing negative numbers only really makes sense in base 10
if (base == 10) {
explicit_bzero(&one_val, sizeof(one_val));
LOWER(one_val) = 1;
explicit_bzero(&two_val, sizeof(two_val));
LOWER(two_val) = 2;
memset(&max_unsigned_val, 0xFF, sizeof(max_unsigned_val));
divmod128(&max_unsigned_val, &two_val, &max_signed_val, &tmp);
if (gt128(number, &max_signed_val)) // negative value
{
sub128(&max_unsigned_val, number, &tmp);
add128(&tmp, &one_val, &tmp);
out[0] = '-';
return tostring128(&tmp, base, out + 1, out_length - 1);
}
}
return tostring128(number, base, out, out_length); // positive value
}