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datetime: supported parse of h's or m's frac part #3

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Merged
sergepetrenko merged 1 commit into from
Mar 2, 2026
Merged

datetime: supported parse of h's or m's frac part #3

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92 changes: 78 additions & 14 deletions dt_parse_iso.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
#include <stddef.h>
#include <stdlib.h>
#include "dt_core.h"
#include "dt_valid.h"

Expand Down Expand Up @@ -62,7 +63,8 @@ static const int pow_10[10] = {
};

/*
* fffffffff
* Read all digits, but convert up to 9 only.
* fffffffff[f...]
*/

static size_t
Expand All @@ -79,49 +81,87 @@ parse_fraction_digits(const unsigned char *p, size_t i, size_t len, int *fp) {
return n;
}

static void
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handle_frac_case(int frac_case, int *fp, int *mp, int *sp)
{
double w = 60.0 * *fp / 1E9; /* .hh or .mm */
switch (frac_case) {
case 1:
*mp = (int) w;
w = 60.0 * (w - *mp); /* .hh -> .mm */
/* fallthrough */
case 2:
*sp = (int) w;
/* We prefer to truncate hour or minute fractions
* to seconds precision for simplicity:
* no rounding = no overflow to mins/hours/etc.
* If somebody want a second fraction,
* they must use explicit representation s,f.
*/
*fp = 0; /* *fp = (int) ((w - *sp) * 1E9); */
break;
default:
abort();
}
}

/*
* The representation of time format is defined in ISO 8601-1:2019, 5.3.1.
* Representations with decimal fraction is defined in 5.3.1.4.
* More than 9 fraction digits are truncated by the routine.
* hh
* hh.fffffffff[f...]
* hh,fffffffff[f...]
* hhmm
* hhmm.fffffffff[f...]
* hhmm,fffffffff[f...]
* hhmmss
* hhmmss.fffffffff
* hhmmss,fffffffff
* hhmmss.fffffffff[f...]
* hhmmss,fffffffff[f...]
*/

size_t
dt_parse_iso_time_basic(const char *str, size_t len, int *sp, int *fp) {
const unsigned char *p;
int h, m, s, f;
size_t n;
int frac_case;

p = (const unsigned char *)str;
n = count_digits(p, 0, len);
m = s = f = 0;
switch (n) {
case 2: /* hh */
h = parse_number(p, 0, 2);
goto hms;
frac_case = 1;
break;
case 4: /* hhmm */
h = parse_number(p, 0, 2);
m = parse_number(p, 2, 2);
goto hms;
frac_case = 2;
break;
case 6: /* hhmmss */
h = parse_number(p, 0, 2);
m = parse_number(p, 2, 2);
s = parse_number(p, 4, 2);
frac_case = 0;
break;
default:
return 0;
}

/* hhmmss.fffffffff */
/* .fffffffff[f...] */
if (n < len && (p[n] == '.' || p[n] == ',')) {
size_t r = parse_fraction_digits(p, ++n, len, &f);
++n;
size_t r = parse_fraction_digits(p, n, len, &f);
if (!r)
return 0;
n += r;

if (frac_case > 0)
handle_frac_case(frac_case, &f, &m, &s);
}

hms:
if (h > 23 || m > 59 || s > 59) {
if (!(h == 24 && m == 0 && s == 0 && f == 0))
return 0;
Expand Down Expand Up @@ -199,18 +239,26 @@ dt_parse_iso_zone_basic(const char *str, size_t len, int *op) {
}

/*
* The representation of time format is defined in ISO 8601-1:2019, 5.3.1.
* Representations with decimal fraction is defined in 5.3.1.4.
* More than 9 fraction digits are truncated by the routine.
* hh
* hh.fffffffff[f...]
* hh,fffffffff[f...]
* hh:mm
* hh:mm.fffffffff[f...]
* hh:mm,fffffffff[f...]
* hh:mm:ss
* hh:mm:ss.fffffffff
* hh:mm:ss,fffffffff
* hh:mm:ss.fffffffff[f...]
* hh:mm:ss,fffffffff[f...]
*/

size_t
dt_parse_iso_time_extended(const char *str, size_t len, int *sp, int *fp) {
const unsigned char *p;
int h, m, s, f;
size_t n;
int frac_case;

p = (const unsigned char *)str;
if (count_digits(p, 0, len) != 2)
Expand All @@ -219,31 +267,43 @@ dt_parse_iso_time_extended(const char *str, size_t len, int *sp, int *fp) {
h = parse_number(p, 0, 2);
m = s = f = 0;
n = 2;
frac_case = 1;

if (len < 3 || p[2] != ':')
if (len < 3 || (p[2] != ':' && p[2] != ',' && p[2] != '.'))
goto hms;
else if (p[2] != ':')
goto parse_frac;

if (count_digits(p, 3, len) != 2)
return 0;

m = parse_number(p, 3, 2);
n = 5;
frac_case = 2;

if (len < 6 || p[5] != ':')
if (len < 6 || (p[5] != ':' && p[5] != ',' && p[5] != '.'))
goto hms;
else if (p[5] != ':')
goto parse_frac;

if (count_digits(p, 6, len) != 2)
return 0;

s = parse_number(p, 6, 2);
n = 8;
frac_case = 0;

/* hh:mm:ss.fffffffff */
parse_frac:
/* .fffffffff[f...] */
if (n < len && (p[n] == '.' || p[n] == ',')) {
size_t r = parse_fraction_digits(p, ++n, len, &f);
++n;
size_t r = parse_fraction_digits(p, n, len, &f);
if (!r)
return 0;
n += r;

if (frac_case > 0)
handle_frac_case(frac_case, &f, &m, &s);
}

hms:
Expand Down Expand Up @@ -665,7 +725,11 @@ dt_parse_iso_date(const char *str, size_t len, dt_t *dtp) {
/*
* Basic Extended
* T12 N/A
* T12.123456789 N/A
* T12,123456789 N/A
* T1230 T12:30
* T1230.123456789 T12:30.123456789
* T1230,123456789 T12:30,123456789
* T123045 T12:30:45
* T123045.123456789 T12:30:45.123456789
* T123045,123456789 T12:30:45,123456789
Expand Down
42 changes: 42 additions & 0 deletions t/parse_iso_time.c
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Original file line number Diff line number Diff line change
Expand Up @@ -123,6 +123,48 @@ const struct good_t {
{ 0, 0, "T000000.0000000", 15 },
{ 0, 0, "T000000.00000000", 16 },
{ 0, 0, "T000000.000000000", 17 },
{ 0, 0, "T00.000000000", 13 },
{ 1800, 0, "T00.5", 5 },
{ 900, 0, "T00.25", 6 },
{ 450, 0, "T00.125", 7 },
{ 1199, 0, "T00.333333333", 13 },
{ 1199, 0, "T00.333333333999", 16 },
{ 3599, 0, "T00.999999999", 13 },
{ 0, 0, "T00,000000000", 13 },
{ 1800, 0, "T00,5", 5 },
{ 900, 0, "T00,25", 6 },
{ 450, 0, "T00,125", 7 },
{ 1199, 0, "T00,333333333", 13 },
{ 1199, 0, "T00,333333333999", 16 },
{ 3599, 0, "T00,999999999", 13 },
{ 0, 0, "T00:00.000000000", 16 },
{ 30, 0, "T00:00.5", 8 },
{ 15, 0, "T00:00.25", 9 },
{ 7, 0, "T00:00.125", 10 },
{ 19, 0, "T00:00.333333333", 16 },
{ 19, 0, "T00:00.333333333999", 19 },
{ 59, 0, "T00:00.999999999", 16 },
{ 0, 0, "T00:00,000000000", 16 },
{ 30, 0, "T00:00,5", 8 },
{ 15, 0, "T00:00,25", 9 },
{ 7, 0, "T00:00,125", 10 },
{ 19, 0, "T00:00,333333333", 16 },
{ 19, 0, "T00:00,333333333999", 19 },
{ 59, 0, "T00:00,999999999", 16 },
{ 0, 0, "T0000.000000000", 15 },
{ 30, 0, "T0000.5", 7 },
{ 15, 0, "T0000.25", 8 },
{ 7, 0, "T0000.125", 9 },
{ 19, 0, "T0000.333333333", 15 },
{ 19, 0, "T0000.333333333999", 18 },
{ 59, 0, "T0000.999999999", 15 },
{ 0, 0, "T0000,000000000", 15 },
{ 30, 0, "T0000,5", 7 },
{ 15, 0, "T0000,25", 8 },
{ 7, 0, "T0000,125", 9 },
{ 19, 0, "T0000,333333333", 15 },
{ 19, 0, "T0000,333333333999", 18 },
{ 59, 0, "T0000,999999999", 15 },
};

const struct bad_t {
Expand Down