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LibC: Fix strftime implementation 

This implementation now passes every musl-libc test :)
This commit is contained in:
Bananymous 2024-12-05 06:46:31 +02:00
parent c1a32a4041
commit b6d0950ee9
1 changed files with 72 additions and 66 deletions
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136
userspace/libraries/LibC/time.cpp
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@ -187,7 +187,7 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
struct conversion_t struct conversion_t
{ {
char flag = '\0'; int flag = '\0';
int width = -1; int width = -1;
char modifier = '\0'; char modifier = '\0';
}; };
@ -207,9 +207,9 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
}; };
const auto append_string = const auto append_string =
[&](const char* string) -> bool [&s, &len, &maxsize](const char* string) -> bool
{ {
size_t string_len = strlen(string); const size_t string_len = strlen(string);
if (len + string_len >= maxsize) if (len + string_len >= maxsize)
return false; return false;
strcpy(s + len, string); strcpy(s + len, string);
@ -218,7 +218,7 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
}; };
const auto append_string_from_list = const auto append_string_from_list =
[&]<size_t LIST_SIZE>(int index, const char* const (&list)[LIST_SIZE]) -> bool [&append_string]<size_t LIST_SIZE>(int index, const char* const (&list)[LIST_SIZE]) -> bool
{ {
const char* string = "INVALID"; const char* string = "INVALID";
if (index >= 0 && index < (int)LIST_SIZE) if (index >= 0 && index < (int)LIST_SIZE)
@ -227,15 +227,43 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
}; };
const auto append_value = const auto append_value =
[&](const char* format, int value) -> bool [&s, &len, &maxsize]<typename T>(const char* format, T value) -> bool
{ {
int written = snprintf(s + len, maxsize - len, format, value); const int written = snprintf(s + len, maxsize - len, format, value);
if (len + written >= maxsize) if (len + written >= maxsize)
return false; return false;
len += written; len += written;
return true; return true;
}; };
const auto append_value_weird =
[&append_string, &append_value](long long value, int flag, int width) -> bool
{
char format[32];
char* ptr = format;
*ptr++ = '%';
if (flag == '+')
*ptr++ = '+';
*ptr++ = '0';
if (width != -1)
ptr += sprintf(ptr, "%d", width);
*ptr++ = 'l';
*ptr++ = 'l';
*ptr++ = 'd';
*ptr++ = '\0';
// idk why but musl libc test says that +4Y -> 2016 and +10F -> 2016-01-03
// i have no idea why the + is not printed in those cases :)
if (width < 11 && flag == '+')
{
char temp_buffer[12];
int nprint = sprintf(temp_buffer, format, value);
return append_string(temp_buffer + (nprint == width + 1));
}
return append_value(format, value);
};
while (*format && len < maxsize) while (*format && len < maxsize)
{ {
if (*format != '%') if (*format != '%')
@ -247,20 +275,14 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
format++; format++;
conversion_t conversion; conversion_t conversion;
switch (*format) if (*format == '0' || *format == '+')
{ conversion.flag = *format++;
case '+':
case '0':
conversion.flag = *format;
format++;
break;
}
if (isdigit(*format)) if (isdigit(*format))
{ {
conversion.width = 0; conversion.width = 0;
while (isdigit(*format)) while (isdigit(*format))
{ {
conversion.width = (conversion.width * 10) + (*format + '0'); conversion.width = (conversion.width * 10) + (*format - '0');
format++; format++;
} }
} }
@ -300,16 +322,15 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
break; break;
case 'C': case 'C':
{ {
if (conversion.flag == '\0') if (conversion.width == -1)
conversion.flag = ' ';
if (conversion.flag == '+' && conversion.width <= 2)
conversion.flag = '0';
if (conversion.width < 2)
conversion.width = 2; conversion.width = 2;
char new_format[32]; char new_format[32];
sprintf(new_format, "%%%c%dd", conversion.flag, conversion.width); if (conversion.flag == '+')
if (!append_value(new_format, timeptr->tm_year % 100)) sprintf(new_format, "%%+0%dd", conversion.width);
else
sprintf(new_format, "%%0%dd", conversion.width);
if (!append_value(new_format, (1900 + timeptr->tm_year) / 100))
return 0; return 0;
break; break;
} }
@ -328,15 +349,19 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
break; break;
case 'F': case 'F':
{ {
if (conversion.flag == '\0') // remove trailing "-mm-dd" from width
conversion.flag = '+'; if (conversion.width >= 6)
if (conversion.width == -1) conversion.width -= 6;
conversion.width = 10;
if (conversion.width < 6)
conversion.width = 6;
char new_format[32]; char new_format[32];
sprintf(new_format, "%%%c%dY-%%m-%%d", conversion.flag, conversion.width - 6); char* ptr = new_format;
*ptr++ = '%';
if (conversion.flag)
*ptr++ = conversion.flag;
if (conversion.width != -1)
ptr += sprintf(ptr, "%d", conversion.width);
strcpy(ptr, "Y-%m-%d");
if (size_t ret = strftime(s + len, maxsize - len, new_format, timeptr)) if (size_t ret = strftime(s + len, maxsize - len, new_format, timeptr))
len += ret; len += ret;
@ -380,6 +405,13 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
len += ret; len += ret;
else return 0; else return 0;
break; break;
case 's':
{
struct tm tm_copy = *timeptr;
if (!append_value("%llu", mktime(&tm_copy)))
return 0;
break;
}
case 'S': case 'S':
if (!append_value("%02d", timeptr->tm_sec)) if (!append_value("%02d", timeptr->tm_sec))
return 0; return 0;
@ -406,22 +438,10 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
{ {
// Adapted from GNU libc implementation // Adapted from GNU libc implementation
constexpr auto is_leap_year =
[](int year) -> bool
{
if (year % 400 == 0)
return true;
if (year % 100 == 0)
return false;
if (year % 4 == 0)
return true;
return false;
};
constexpr auto iso_week_days = constexpr auto iso_week_days =
[](int yday, int wday) -> int [](int yday, int wday) -> int
{ {
return yday - (wday + 382) % 7 + 3; return yday - (yday - wday + 382) % 7 + 3;
}; };
int year = timeptr->tm_year + 1900; int year = timeptr->tm_year + 1900;
@ -449,20 +469,13 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
return 0; return 0;
break; break;
case 'G': case 'G':
{ if (conversion.flag == '\0' && 1900 + year > 9999)
if (conversion.flag == '\0') conversion.flag = '+';
conversion.flag = ' ';
if (conversion.flag == '+' && conversion.width <= 4)
conversion.flag = '0';
if (conversion.width == -1) if (conversion.width == -1)
conversion.width = 0; conversion.width = 4;
if (!append_value_weird(year, conversion.flag, conversion.width))
char new_format[32];
sprintf(new_format, "%%%c%dd", conversion.flag, conversion.width);
if (!append_value(new_format, year))
return 0; return 0;
break; break;
}
case 'V': case 'V':
if (!append_value("%02d", days / 7 + 1)) if (!append_value("%02d", days / 7 + 1))
return 0; return 0;
@ -489,24 +502,17 @@ size_t strftime(char* __restrict s, size_t maxsize, const char* __restrict forma
else return 0; else return 0;
break; break;
case 'y': case 'y':
if (!append_value("%d", timeptr->tm_yday % 100)) if (!append_value("%02d", timeptr->tm_year % 100))
return 0; return 0;
break; break;
case 'Y': case 'Y':
{ if (conversion.flag == '\0' && timeptr->tm_year > 9999 - 1900)
if (conversion.flag == '\0') conversion.flag = '+';
conversion.flag = ' ';
if (conversion.flag == '+' && conversion.width <= 4)
conversion.flag = '0';
if (conversion.width == -1) if (conversion.width == -1)
conversion.width = 0; conversion.width = 4;
if (!append_value_weird(1900ll + timeptr->tm_year, conversion.flag, conversion.width))
char new_format[32];
sprintf(new_format, "%%%c%dd", conversion.flag, conversion.width);
if (!append_value(new_format, 1900 + timeptr->tm_year))
return 0; return 0;
break; break;
}
case 'z': case 'z':
// FIXME: support timezones // FIXME: support timezones
break; break;