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stellar: rework number formatting to not use double

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This commit is contained in:
Pavol Rusnak 2018-10-23 15:25:19 +02:00
parent cc630a1ebb
commit 1e602998c7
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GPG Key ID: 91F3B339B9A02A3D
1 changed files with 18 additions and 13 deletions
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31
firmware/stellar.c
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@ -448,7 +448,7 @@ bool stellar_confirmManageOfferOp(const StellarManageOfferOp *msg)
char str_buying[32];
char str_buying_asset[32];
char str_price[17];
char str_price[32];
stellar_format_asset(&(msg->buying_asset), str_buying_asset, sizeof(str_buying_asset));
stellar_format_price(msg->price_n, msg->price_d, str_price, sizeof(str_price));
@ -528,7 +528,7 @@ bool stellar_confirmCreatePassiveOfferOp(const StellarCreatePassiveOfferOp *msg)
char str_buying[32];
char str_buying_asset[32];
char str_price[17];
char str_price[32];
stellar_format_asset(&(msg->buying_asset), str_buying_asset, sizeof(str_buying_asset));
stellar_format_price(msg->price_n, msg->price_d, str_price, sizeof(str_price));
@ -1273,27 +1273,32 @@ void stellar_format_price(uint32_t numerator, uint32_t denominator, char *out, s
{
memset(out, 0, outlen);
// early exist for invalid denominator
// early exit for invalid denominator
if (denominator == 0) {
strlcpy(out, _("[Invalid Price]"), outlen);
return;
}
int scale = 0;
double dbl_value = (double)numerator / (double)denominator;
// early exit for zero
if (numerator == 0) {
strlcpy(out, "0", outlen);
return;
}
// Multiply by 10 until the value is larger than the largest possible offer size
// Largest possible offer size is UINT32_MAX (4294967296)
while (dbl_value < UINT32_MAX) {
dbl_value *= (double)10;
int scale = 0;
uint64_t value = numerator;
while (value < (UINT64_MAX / 10)) {
value *= 10;
scale++;
}
value /= denominator;
while (value < (UINT64_MAX / 10)) {
value *= 10;
scale++;
}
// Cast back to an integer
uint64_t scaled_value = (uint64_t) dbl_value;
// Format with bn_format_uint64
bn_format_uint64(scaled_value, NULL, NULL, scale, 0, false, out, outlen);
bn_format_uint64(value, NULL, NULL, scale, 0, false, out, outlen);
}
/*