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-rw-r--r--lib/mlibc/options/posix/generic/time.cpp505
1 files changed, 505 insertions, 0 deletions
diff --git a/lib/mlibc/options/posix/generic/time.cpp b/lib/mlibc/options/posix/generic/time.cpp
new file mode 100644
index 0000000..14193af
--- /dev/null
+++ b/lib/mlibc/options/posix/generic/time.cpp
@@ -0,0 +1,505 @@
+#include <ctype.h>
+#include <langinfo.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+#include <bits/ensure.h>
+#include <mlibc/strings.hpp>
+
+namespace {
+
+int month_to_day(int month) {
+ switch(month){
+ case 0: return 0;
+ case 1: return 31;
+ case 2: return 59;
+ case 3: return 90;
+ case 4: return 120;
+ case 5: return 151;
+ case 6: return 181;
+ case 7: return 212;
+ case 8: return 243;
+ case 9: return 273;
+ case 10: return 304;
+ case 11: return 334;
+ }
+ return -1;
+}
+
+int is_leapyear(int year) {
+ return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
+}
+
+int month_and_year_to_day_in_year(int month, int year){
+ int day = month_to_day(month);
+ if(is_leapyear(year) && month < 2)
+ return day + 1;
+
+ return day;
+}
+
+int target_determination(int month) {
+ switch(month){
+ case 0: return 3;
+ case 1: return 14;
+ case 2: return 14;
+ case 3: return 4;
+ case 4: return 9;
+ case 5: return 6;
+ case 6: return 11;
+ case 7: return 8;
+ case 8: return 5;
+ case 9: return 10;
+ case 10: return 7;
+ case 11: return 12;
+ }
+
+ return -1;
+}
+
+int doom_determination(int full_year) {
+ int century = full_year / 100;
+ int anchor = 2 + 5 * (century % 4) % 7;
+
+ int year = full_year % 100;
+
+ if(year % 2)
+ year += 11;
+
+ year /= 2;
+
+ if(year % 2)
+ year += 11;
+
+ return 7 - (year % 7) + anchor;
+}
+
+//Determine day of week through the doomsday algorithm.
+int day_determination(int day, int month, int year) {
+ int doom = doom_determination(year);
+ bool leap = is_leapyear(year);
+
+ int target = target_determination(month);
+ if(leap && month < 2)
+ target++;
+
+ int doom_dif = (day - target) % 7;
+ return (doom + doom_dif) % 7;
+}
+
+struct strptime_internal_state {
+ bool has_century;
+ bool has_year;
+ bool has_month;
+ bool has_day_of_month;
+ bool has_day_of_year;
+ bool has_day_of_week;
+
+ bool full_year_given;
+
+ int century;
+
+ size_t format_index;
+ size_t input_index;
+};
+
+char *strptime_internal(const char *__restrict input, const char *__restrict format,
+ struct tm *__restrict tm, struct strptime_internal_state *__restrict state) {
+ auto matchLanginfoItem = [&] (int start, size_t num, int &dest, bool &flag) -> bool {
+ for(size_t i = start; i < (start + num); i++) {
+ const char *mon = nl_langinfo(i);
+ size_t len = strlen(mon);
+ if(mlibc::strncasecmp(&input[state->input_index], mon, len))
+ continue;
+ state->input_index += len;
+ dest = i - start;
+ flag = true;
+ return true;
+ }
+ return false;
+ };
+
+ auto matchNumericRange = [&] (int start, int end, int &dest, bool *flag) -> bool {
+ int product = 0, n = 0;
+ sscanf(&input[state->input_index], "%d%n", &product, &n);
+ if(n == 0 || 2 < n)
+ return false;
+ if(product < start || product > end)
+ return false;
+ state->input_index += n;
+ dest = product;
+ if(flag) *flag = true;
+ return true;
+ };
+
+ while(isspace(input[state->input_index]))
+ state->input_index++;
+
+ if(input[state->input_index] == '\0')
+ return NULL;
+
+ while(format[state->format_index] != '\0'){
+ if(format[state->format_index] != '%'){
+ if(isspace(format[state->format_index])){
+ while(isspace(input[state->input_index++]));
+ state->input_index--;
+ }
+ else {
+ if(format[state->format_index] != input[state->input_index++])
+ return NULL;
+ }
+ state->format_index++;
+ continue;
+ }
+ state->format_index++;
+ switch(format[state->format_index]){
+ case '%':
+ if(input[state->input_index++] != '%')
+ return NULL;
+ break;
+ case 'a':
+ case 'A': {
+ if (!matchLanginfoItem(DAY_1, 7, tm->tm_wday, state->has_day_of_week) && \
+ !matchLanginfoItem(ABDAY_1, 7, tm->tm_wday, state->has_day_of_week))
+ return NULL;
+ break;
+ }
+ case 'b':
+ case 'B':
+ case 'h': {
+ if (!matchLanginfoItem(MON_1, 12, tm->tm_mon, state->has_month) && \
+ !matchLanginfoItem(ABMON_1, 12, tm->tm_mon, state->has_month))
+ return NULL;
+ break;
+ }
+ case 'c':
+ __ensure(!"strptime() %c directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'C': {
+ int product = 0, n = 0;
+ sscanf(&input[state->input_index], "%d%n", &product, &n);
+ if(n == 0 || 2 < n)
+ return NULL;
+ state->input_index += n;
+ state->century = product;
+ state->has_century = true;
+ break;
+ }
+ case 'd': //`%d` and `%e` are equivalent
+ case 'e': {
+ if(!matchNumericRange(1, 31, tm->tm_mday, &state->has_day_of_month))
+ return NULL;
+ break;
+ }
+ case 'D': { //equivalent to `%m/%d/%y`
+ size_t pre_fi = state->format_index;
+ state->format_index = 0;
+
+ char *result = strptime_internal(input, "%m/%d/%y", tm, state);
+ if(result == NULL)
+ return NULL;
+
+ state->format_index = pre_fi;
+ break;
+ }
+ case 'H': {
+ if(!matchNumericRange(0, 23, tm->tm_hour, nullptr))
+ return NULL;
+ break;
+ }
+ case 'I': {
+ if(!matchNumericRange(1, 12, tm->tm_hour, nullptr))
+ return NULL;
+ break;
+ }
+ case 'j': {
+ if(!matchNumericRange(1, 366, tm->tm_yday, &state->has_day_of_year))
+ return NULL;
+ tm->tm_yday--;
+ break;
+ }
+ case 'm': {
+ if(!matchNumericRange(1, 12, tm->tm_mon, &state->has_month))
+ return NULL;
+ tm->tm_mon--;
+ break;
+ }
+ case 'M': {
+ if(!matchNumericRange(0, 59, tm->tm_min, nullptr))
+ return NULL;
+ break;
+ }
+ case 'n':
+ case 't': {
+ size_t n = 0;
+ while(isspace(input[state->input_index++]))
+ n++;
+ if(n == 0)
+ return NULL;
+ state->input_index--;
+ break;
+ }
+ case 'p': {
+ const char *meridian_str = nl_langinfo(AM_STR);
+ size_t len = strlen(meridian_str);
+ if (!mlibc::strncasecmp(&input[state->input_index], meridian_str, len)) {
+ tm->tm_hour %= 12;
+ state->input_index += len;
+ break;
+ }
+ meridian_str = nl_langinfo(PM_STR);
+ len = strlen(meridian_str);
+ if (!mlibc::strncasecmp(&input[state->input_index], meridian_str, len)) {
+ tm->tm_hour %= 12;
+ tm->tm_hour += 12;
+ state->input_index += len;
+ break;
+ }
+ break;
+ }
+ case 'r': { //equivalent to `%I:%M:%S %p`
+ size_t pre_fi = state->format_index;
+ state->format_index = 0;
+
+ char *result = strptime_internal(input, "%I:%M:%S %p", tm, state);
+ if(result == NULL)
+ return NULL;
+
+ state->format_index = pre_fi;
+ break;
+ }
+ case 'R': { //equivalent to `%H:%M`
+ size_t pre_fi = state->format_index;
+ state->format_index = 0;
+
+ char *result = strptime_internal(input, "%H:%M", tm, state);
+ if(result == NULL)
+ return NULL;
+
+ state->format_index = pre_fi;
+ break;
+ }
+ case 'S': {
+ if(!matchNumericRange(0, 60, tm->tm_sec, nullptr))
+ return NULL;
+ break;
+ }
+ case 'T': { //equivalent to `%H:%M:%S`
+ size_t pre_fi = state->format_index;
+ state->format_index = 0;
+
+ char *result = strptime_internal(input, "%H:%M:%S", tm, state);
+ if(result == NULL)
+ return NULL;
+
+ state->format_index = pre_fi;
+ break;
+ }
+ case 'U':
+ __ensure(!"strptime() %U directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'w': {
+ int product = 0, n = 0;
+ sscanf(&input[state->input_index], "%d%n", &product, &n);
+ if(n == 0 || 1 < n)
+ return NULL;
+ state->input_index += n;
+ tm->tm_wday = product;
+ state->has_day_of_week = true;
+ break;
+ }
+ case 'W':
+ __ensure(!"strptime() %W directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'x':
+ __ensure(!"strptime() %x directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'X':
+ __ensure(!"strptime() %X directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'y': {
+ int product = 0, n = 0;
+ sscanf(&input[state->input_index], "%d%n", &product, &n);
+ if(n == 0 || 2 < n)
+ return NULL;
+ if(product < 69)
+ product += 100;
+ state->input_index += n;
+ tm->tm_year = product;
+ state->has_year = true;
+ break;
+ }
+ case 'Y': {
+ int product = 0, n = 0;
+ sscanf(&input[state->input_index], "%d%n", &product, &n);
+ if(n == 0 || 4 < n)
+ return NULL;
+ state->input_index += n;
+ tm->tm_year = product - 1900;
+ state->has_year = true;
+ state->has_century = true;
+ state->full_year_given = true;
+ state->century = product / 100;
+ break;
+ }
+ case 'F': { //GNU extensions
+ //equivalent to `%Y-%m-%d`
+ size_t pre_fi = state->format_index;
+ state->format_index = 0;
+
+ char *result = strptime_internal(input, "%Y-%m-%d", tm, state);
+ if(result == NULL)
+ return NULL;
+
+ state->format_index = pre_fi;
+ break;
+ }
+ case 'g':
+ __ensure(!"strptime() %g directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'G':
+ __ensure(!"strptime() %G directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'u': {
+ if(!matchNumericRange(1, 7, tm->tm_wday, nullptr))
+ return NULL;
+ tm->tm_wday--;
+ break;
+ }
+ case 'V':
+ __ensure(!"strptime() %V directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'z':
+ __ensure(!"strptime() %z directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'Z':
+ __ensure(!"strptime() %Z directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 's': //end of GNU extensions
+ __ensure(!"strptime() %s directive unimplemented.");
+ __builtin_unreachable();
+ break;
+ case 'E': { //locale-dependent date & time representation
+ __ensure(!"strptime() %E* directives unimplemented.");
+ __builtin_unreachable();
+ /*
+ state->format_index++;
+ switch(format[state->format_index]){
+ case 'c':
+ break;
+ case 'C':
+ break;
+ case 'x':
+ break;
+ case 'X':
+ break;
+ case 'y':
+ break;
+ case 'Y':
+ break;
+ default:
+ return NULL;
+ }
+ */
+ }
+ case 'O': { //locale-dependent numeric symbols
+ __ensure(!"strptime() %O* directives unimplemented.");
+ __builtin_unreachable();
+ /*
+ state->format_index++;
+ switch(format[state->format_index]){
+ case 'd':
+ case 'e':
+ break;
+ case 'H':
+ break;
+ case 'I':
+ break;
+ case 'm':
+ break;
+ case 'M':
+ break;
+ case 'S':
+ break;
+ case 'U':
+ break;
+ case 'w':
+ break;
+ case 'W':
+ break;
+ case 'y':
+ break;
+ default:
+ return NULL;
+ }
+ */
+ }
+ default:
+ return NULL;
+ }
+ state->format_index++;
+ }
+
+ return (char*)input + state->input_index;
+}
+
+} //anonymous namespace
+
+char *strptime(const char *__restrict s, const char *__restrict format, struct tm *__restrict tm){
+ struct strptime_internal_state state = {};
+
+ char *result = strptime_internal(s, format, tm, &state);
+
+ if(result == NULL)
+ return NULL;
+
+ if(state.has_century && !state.full_year_given){
+ int full_year = state.century * 100;
+
+ if(state.has_year){
+ //Compensate for default century-adjustment of `%j` operand
+ if(tm->tm_year >= 100)
+ full_year += tm->tm_year - 100;
+ else
+ full_year += tm->tm_year;
+ }
+
+ tm->tm_year = full_year - 1900;
+
+ state.has_year = true;
+ }
+
+ if(state.has_month && !state.has_day_of_year){
+ int day = 0;
+ if(state.has_year)
+ day = month_and_year_to_day_in_year(tm->tm_mon, tm->tm_year);
+ else
+ day = month_to_day(tm->tm_mon);
+
+ tm->tm_yday = day + tm->tm_mday - 1;
+ state.has_day_of_year = true;
+ }
+
+ if(state.has_year && !state.has_day_of_week){
+ if(!state.has_month && !state.has_day_of_month){
+ tm->tm_wday = day_determination(0, 0, tm->tm_year + 1900);
+ }
+ else if(state.has_month && state.has_day_of_month){
+ tm->tm_wday = day_determination(tm->tm_mday, tm->tm_mon, tm->tm_year + 1900);
+ }
+ state.has_day_of_week = true;
+ }
+
+ return result;
+}
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