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Fix and add support for 'g'
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@MaJerle
MaJerle committed Sep 2, 2020
1 parent e674732 commit 84c1746
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Showing 2 changed files with 77 additions and 16 deletions.
11 changes: 11 additions & 0 deletions dev/VisualStudio/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -69,6 +69,17 @@ main(void) {

lwprintf_init(lwprintf_output);


printf_run(NULL, "Precision: %3d, %.*g", 17, 17, 0.0001234567);

for (int i = 0; i < 20; ++i) {
printf_run(NULL, "Precision: %3d, %.*g", i, i, 432432423.342321321);
}
for (int i = 0; i < 20; ++i) {
printf_run(NULL, "Precision: %3d, %.*g", i, i, 0.0001234567);
}


printf_run(NULL, "%.4f", 3.23321321);
printf_run(NULL, "%.45f", 3.23321321);

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82 changes: 66 additions & 16 deletions lwprintf/src/lwprintf/lwprintf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -66,13 +66,14 @@ typedef struct {

short digits_cnt_integer_part; /*!< Number of digits for integer part */
short digits_cnt_decimal_part; /*!< Number of digits for decimal part */
short digits_cnt_decimal_part_useful; /*!< Number of useful digits to print */
} float_num_t;

/* Powers of 10 from beginning up to precision level */
static const float_long_t
powers_of_10[] = { 1E00, 1E01, 1E02, 1E03, 1E04, 1E05, 1E06, 1E07, 1E08, 1E09,
#if LWPRINTF_CFG_SUPPORT_LONG_LONG
1E10, 1E11, 1E12, 1E13, 1E14, 1E15
1E10, 1E11, 1E12, 1E13, 1E14, 1E15, 1E16, 1E17, 1E18
#endif /* LWPRINTF_CFG_SUPPORT_LONG_LONG */
};

Expand Down Expand Up @@ -500,7 +501,13 @@ prv_signed_longlong_int_to_str(lwprintf_int_t* p, signed long long int num) {
* \brief Calculate necessary parameters for input number
*/
static void
prv_calculate_dbl_num_data(lwprintf_int_t* p, float_num_t* n, double num) {
prv_calculate_dbl_num_data(lwprintf_int_t* p, float_num_t* n, double num, const char type) {
memset(n, 0x00, sizeof(*n));

if (p->m.precision >= LWPRINTF_ARRAYSIZE(powers_of_10)) {
p->m.precision = LWPRINTF_ARRAYSIZE(powers_of_10) - 1;
}

/*
* Get integer and decimal parts, both in integer formats
*
Expand All @@ -513,7 +520,7 @@ prv_calculate_dbl_num_data(lwprintf_int_t* p, float_num_t* n, double num) {
* This is used for rounding of last digit (if necessary)
*/
n->integer_part = (float_long_t)num;
n->decimal_part_dbl = (num - n->integer_part) * powers_of_10[p->m.precision];
n->decimal_part_dbl = (num - n->integer_part) * (double)powers_of_10[p->m.precision];
n->decimal_part = (float_long_t)n->decimal_part_dbl;
n->diff = n->decimal_part_dbl - (float_long_t)n->decimal_part;

Expand Down Expand Up @@ -542,11 +549,17 @@ prv_calculate_dbl_num_data(lwprintf_int_t* p, float_num_t* n, double num) {
float_long_t tmp;
for (n->digits_cnt_integer_part = 0, tmp = n->integer_part; tmp > 0; ++n->digits_cnt_integer_part, tmp /= 10) {}
}
if (n->decimal_part == 0) {
n->digits_cnt_decimal_part = 1;
} else {
float_long_t tmp;
for (n->digits_cnt_decimal_part = 0, tmp = n->decimal_part; tmp > 0; ++n->digits_cnt_decimal_part, tmp /= 10) {}
n->digits_cnt_decimal_part = p->m.precision;

/* Calculate minimum useful digits for decimal (excl last useless zeros) */
if (type == 'g') {
float_long_t tmp = n->decimal_part;
int adder, i;
for (adder = 0, i = 0; tmp > 0 || i < p->m.precision; tmp /= 10, n->digits_cnt_decimal_part_useful += adder, ++i) {
if (adder == 0 && (tmp % 10) > 0) {
adder = 1;
}
}
}
}

Expand Down Expand Up @@ -596,7 +609,9 @@ prv_double_to_str(lwprintf_int_t* p, double in_num) {
/* Engineering mode check for number of exponents */
if (def_type == 'e' || def_type == 'g'
|| in_num > (powers_of_10[LWPRINTF_ARRAYSIZE(powers_of_10) - 1])) {/* More vs what float can hold */
p->m.type = 'e';
if (p->m.type != 'g') {
p->m.type = 'e';
}

/* Normalize number to be between 0 and 1 and count decimals for exponent */
if (in_num < 1) {
Expand All @@ -609,7 +624,7 @@ prv_double_to_str(lwprintf_int_t* p, double in_num) {

/* Check precision data */
chosen_precision = p->m.precision; /* This is default value coming from app */
if (p->m.precision >= LWPRINTF_ARRAYSIZE(powers_of_10) - 1) {
if (p->m.precision >= LWPRINTF_ARRAYSIZE(powers_of_10)) {
p->m.precision = LWPRINTF_ARRAYSIZE(powers_of_10) - 1; /* Limit to maximum precision */
/*
* Precision is lower than the one selected by app (or user).
Expand Down Expand Up @@ -647,7 +662,30 @@ prv_double_to_str(lwprintf_int_t* p, double in_num) {
*/

/* Calculate data for number */
prv_calculate_dbl_num_data(p, &dblnum, in_num);
prv_calculate_dbl_num_data(p, &dblnum, def_type == 'e' ? in_num : orig_num, def_type);

/* Set type G */
if (def_type == 'g') {
/* As per standard to decide level of precision */
if (exp_cnt >= -4 && exp_cnt < p->m.precision) {
if (p->m.precision > exp_cnt) {
p->m.precision -= exp_cnt + 1;
chosen_precision -= exp_cnt + 1;
} else {
p->m.precision = 0;
chosen_precision = 0;
}
p->m.type = 'f';
in_num = orig_num;
} else {
p->m.type = 'e';
if (p->m.precision > 0) {
--p->m.precision;
--chosen_precision;
}
}
prv_calculate_dbl_num_data(p, &dblnum, in_num, def_type);
}

/* Set number of digits to display */
digits_cnt = dblnum.digits_cnt_integer_part;
Expand Down Expand Up @@ -686,20 +724,32 @@ prv_double_to_str(lwprintf_int_t* p, double in_num) {
for (i = 0; dblnum.decimal_part > 0; dblnum.decimal_part /= 10, ++i) {
str[i] = '0' + (dblnum.decimal_part % 10);
}

/* Output relevant zeros first, string to print is opposite way */
for (x = i; x < p->m.precision; ++x) {
p->out_fn(p, '0');
if (def_type == 'g') {
/* TODO: This is to be checked */
for (x = 0; x < p->m.precision - i; ++x, --dblnum.digits_cnt_decimal_part_useful) {
p->out_fn(p, '0');
}
} else {
for (x = i; x < p->m.precision; ++x) {
p->out_fn(p, '0');
}
}

/* Now print string itself */
for (; i > 0; --i) {
p->out_fn(p, str[i - 1]);
if (def_type == 'g' && --dblnum.digits_cnt_decimal_part_useful == 0) {
break;
}
}

/* Print ending zeros if selected precision is bigger than maximum supported */
for (; x < chosen_precision; ++x) {
p->out_fn(p, '0');
if (def_type != 'g') {
for (; x < chosen_precision; ++x) {
p->out_fn(p, '0');
}
}
}

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