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Fixed floating point formatting 

When decimal_prec is 0 and the value is negative and needs rounding subtract 1, instead of adding 1
When decimal_prec > 0 round before printing the integer part, instead of after
pull/15152/head
sytse 2021-10-21 22:42:11 +02:00
parent 1c6fb3b4c5
commit b99584d16d
1 changed files with 34 additions and 25 deletions
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59
platform/source/minimal-printf/mbed_printf_implementation.c
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@ -267,20 +267,53 @@ static void mbed_minimal_formatted_string_double(char *buffer, size_t length, in
{
/* get integer part */
MBED_SIGNED_STORAGE integer = value;
/* fractional part represented as the int that will be formatted after the dot, e.g. 95 for 1.95 */
MBED_SIGNED_STORAGE decimal = 0;
if (dec_precision == PRECISION_DEFAULT) {
dec_precision = MBED_CONF_PLATFORM_MINIMAL_PRINTF_SET_FLOATING_POINT_MAX_DECIMALS;
}
if (dec_precision != 0) {
/* get decimal part */
MBED_SIGNED_STORAGE precision = 1;
for (int index = 0; index < dec_precision; index++) {
precision *= 10;
}
/* Multiply the frac part so we get an int value with the required accuracy.
E.g. For 0.1234 and dec_precision=3 you'd get 123.4 */
double decimal_double = (value - integer) * precision;
if (value < 0) {
/* The part after the dot does not have a sign, so negate the value before rounding */
decimal = -decimal_double + 0.5;
if (decimal >= precision)
{
/* Rounding carries over to value's integer part (e.g. -1.95 with dec_precision=1 -> -2.0) */
integer--;
decimal = 0;
}
} else {
/* Round the value */
decimal = decimal_double + 0.5;
if (decimal >= precision)
{
/* Rounding carries over to value's integer part (e.g. 1.95 with dec_precision=1 -> 2.0) */
integer++;
decimal = 0;
}
}
width_size -= dec_precision + 1; // decimal precision plus '.'
if (width_size < 0) {
width_size = 0;
}
} else {
value = (value - integer) * 1.0;
if (!((value > -0.5) && (value < 0.5))) {
if (value > 0.5) {
integer++;
} else if (value < -0.5) {
integer--;
}
}
@ -294,30 +327,6 @@ static void mbed_minimal_formatted_string_double(char *buffer, size_t length, in
if (dec_precision != 0) {
/* write decimal point */
mbed_minimal_putchar(buffer, length, result, '.', stream);
/* get decimal part */
double precision = 1.0;
for (size_t index = 0; index < dec_precision; index++) {
precision *= 10;
}
value = (value - integer) * precision;
/* convert to positive number */
if (value < 0.0) {
value *= -1.0;
}
MBED_UNSIGNED_STORAGE decimal = value;
/* round up or down */
value -= decimal;
if (!((value > -0.5) && (value < 0.5))) {
decimal++;
}
/* write decimal part */
mbed_minimal_formatted_string_integer(buffer, length, result, decimal, INT_UNSIGNED, dec_precision, true, stream);
}