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fixup! Add strptime(3).

This commit is contained in:
Jonas 'Sortie' Termansen 2023-03-21 23:57:19 +01:00
parent d2c98889bd
commit aacec27864
1 changed files with 75 additions and 41 deletions
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116
libc/time/strptime.c
View File

@ -20,6 +20,7 @@
#include <ctype.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <time.h>
@ -28,16 +29,15 @@
#define strptime mystrptime
#endif
static const char* wdays[] = {"sunday", "monday", "tuesday", "wednesday",
"thursday", "friday", "saturday", NULL};
static const char* months[] = {"january", "february", "march", "april", "may",
"june", "july", "august", "september", "october",
"november", "december", NULL};
static const char* wdays[] = {"Sunday", "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday", NULL};
static const char* months[] = {"January", "February", "March", "April", "May",
"June", "July", "August", "September", "October",
"November", "December", NULL};
// TODO: Maximum width.
static const char* strptime_match(const char* str,
int* output,
const char* const* list)
static const char* strptime_str(const char* str,
int* output,
const char* const* list)
{
for ( int i = 0; list[i]; i++ )
{
@ -50,21 +50,29 @@ static const char* strptime_match(const char* str,
return NULL;
}
// TODO: Maximum width.
static const char* strptime_digits(const char* str,
int* output,
int minimum,
int maximum,
int offset)
static const char* strptime_num(const char* str,
int* output,
int minimum,
int maximum,
size_t min_digits,
size_t max_digits,
int offset)
{
if ( *str < '0'|| '9' < *str )
return NULL;
// TODO: More exact with number of digits.
int value = 0;
while ( '0' <= *str && *str <= '9' )
if ( __builtin_mul_overflow(value, 10, &value) ||
__builtin_add_overflow(value, *str++ - '0', &value) )
size_t i = 0;
while ( i < max_digits )
{
if ( str[i] < '0'|| '9' < str[i] )
{
if ( min_digits <= i )
break;
return NULL;
}
if ( __builtin_mul_overflow(value, 10, &value) ||
__builtin_add_overflow(value, str[i++] - '0', &value) )
return NULL;
}
str += i;
if ( value < minimum || maximum < value )
return NULL;
if ( __builtin_add_overflow(value, offset, &value) )
@ -78,6 +86,7 @@ char* strptime(const char* restrict str,
{
bool pm = false;
bool need_mktime = false;
int year_high = -1, year_low = -1;
for ( size_t i = 0; format[i]; )
{
if ( isspace((unsigned char) format[i]) )
@ -100,6 +109,7 @@ char* strptime(const char* restrict str,
i++;
if ( format[i] == '0' || format[i] == '+' )
i++;
bool has_width = '0' <= format[i] && format[i] <= '9';
size_t width = 0;
while ( '0' <= format[i] && format[i] <= '9' )
width = width * 10 + (format[i++] - '0');
@ -113,35 +123,40 @@ char* strptime(const char* restrict str,
switch ( format[i] )
{
case 'a':
case 'A': str = strptime_match(str, &tm->tm_wday, wdays); break;
case 'A': str = strptime_str(str, &tm->tm_wday, wdays); break;
case 'b':
case 'B':
case 'h':
str = strptime_match(str, &tm->tm_mon, months);
str = strptime_str(str, &tm->tm_mon, months);
need_mktime = true;
break;
// TODO: %c locale time and date
// TODO: %C century
case 'c': str = strptime(str, "%a %b %e %H:%M:%S %Y", tm); break;
case 'C': str = strptime_num(str, &year_high, 0, 99, 1, 2, 0); break;
case 'd':
case 'e':
str = strptime_digits(str, &tm->tm_mday, 1, 31, 0);
str = strptime_num(str, &tm->tm_mday, 1, 31, 1, 2, 0);
need_mktime = true;
break;
case 'D': str = strptime(str, "%m/%d/%y", tm); break;
case 'H': str = strptime_digits(str, &tm->tm_hour, 0, 23, 0); break;
case 'H': str = strptime_num(str, &tm->tm_hour, 0, 23, 1, 2, 0); break;
case 'I':
str = strptime_digits(str, &tm->tm_hour, 1, 12, 0);
str = strptime_num(str, &tm->tm_hour, 1, 12, 1, 2, 0);
if ( tm->tm_hour == 12 )
tm->tm_hour = 0;
break;
case 'j': str = strptime_digits(str, &tm->tm_yday, 1, 366, -1); break;
case 'j': str = strptime_num(str, &tm->tm_yday, 1, 366, 3, 3, -1); break;
case 'm':
str = strptime_digits(str, &tm->tm_mon, 1, 12, -1);
str = strptime_num(str, &tm->tm_mon, 1, 12, 1, 2, -1);
need_mktime = true;
break;
case 'M': str = strptime_digits(str, &tm->tm_min, 0, 59, 0); break;
// TODO: %n whitesapce
// TODO: %t whitespace
case 'M': str = strptime_num(str, &tm->tm_min, 0, 59, 1, 2, 0); break;
case 'n':
case 't':
if ( !isspace((unsigned char) *str) )
return NULL;
do str++;
while ( isspace((unsigned char) *str) );
break;
case 'p':
if ( !strncasecmp(str, "am", 2) )
str += 2, pm = false;
@ -152,17 +167,22 @@ char* strptime(const char* restrict str,
break;
case 'r': str = strptime(str, "%I:%M:%S %p", tm); break;
case 'R': str = strptime(str, "%H:%M", tm); break;
case 'S': str = strptime_digits(str, &tm->tm_sec, 0, 60, 0); break;
case 'S': str = strptime_num(str, &tm->tm_sec, 0, 60, 1, 2, 0); break;
case 'T': str = strptime(str, "%H:%M:%S", tm); break;
// TODO: %U week number
case 'w': str = strptime_digits(str, &tm->tm_wday, 0, 6, 0); break;
case 'w': str = strptime_num(str, &tm->tm_wday, 0, 6, 1, 1, 0); break;
// TODO: %W week number
case 'x': str = strptime(str, "%m/%d/%Y", tm); break;
case 'X': str = strptime(str, "%H:%M:%S", tm); break;
// TODO: %y non-century year
case 'y': str = strptime_num(str, &year_low, 0, 99, 1, 2, 0); break;
case 'Y':
// TODO: Minimum yield width.
str = strptime_digits(str, &tm->tm_year, INT_MIN, INT_MAX, -1900);
// POSIX divergence: Avoid year 10k problem by allowing more than
// four characters by default.
if ( !has_width )
width = SIZE_MAX;
// TODO: Allow leading + and - per POSIX.
str = strptime_num(str, &tm->tm_year, INT_MIN, INT_MAX, 1, width,
-1900);
need_mktime = true;
break;
case 'z':
@ -170,8 +190,8 @@ char* strptime(const char* restrict str,
if ( *str != '-' || *str != '+' )
return NULL;
int hours, minutes;
if ( !(str = strptime_digits(str, &hours, -12, 12, 0)) ||
!(str = strptime_digits(str, &minutes, 0, 59, 0)) )
if ( !(str = strptime_num(str, &hours, -12, 12, 2, 2, 0)) ||
!(str = strptime_num(str, &minutes, 0, 59, 2, 2, 0)) )
return NULL;
tm->tm_isdst = 0;
// TODO: What is done with this timezone information?
@ -198,8 +218,22 @@ char* strptime(const char* restrict str,
{
if ( pm )
tm->tm_hour += 12;
if ( year_high != -1 || year_low != -1 )
{
if ( year_high == -1 )
year_high = year_low < 70 ? 20 : 19;
else if ( year_low == -1 )
year_low = 0;
tm->tm_year = year_high * 100 + year_low - 1900;
need_mktime = true;
}
if ( need_mktime )
mktime(tm);
{
struct tm copy = *tm;
mktime(&copy);
tm->tm_wday = copy.tm_wday;
tm->tm_yday = copy.tm_yday;
}
}
return (char*) str;
}