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