1 files changed, 112 insertions, 0 deletions
diff --git a/subprojects/exess/src/date.c b/subprojects/exess/src/date.c
new file mode 100644
index 00000000..77b336f7
--- /dev/null
+++ b/subprojects/exess/src/date.c
@@ -0,0 +1,112 @@
+/*
+  Copyright 2019-2021 David Robillard <d@drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include "date_utils.h"
+#include "read_utils.h"
+#include "timezone.h"
+#include "write_utils.h"
+
+#include "exess/exess.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+ExessResult
+read_date_numbers(ExessDate* const out, const char* const str)
+{
+  // Read year at the beginning
+  size_t      i = skip_whitespace(str);
+  ExessResult r = read_year_number(&out->year, str + i);
+  if (r.status) {
+    return result(r.status, i + r.count);
+  }
+
+  // Read year-month delimiter
+  i += r.count;
+  if (str[i] != '-') {
+    return result(EXESS_EXPECTED_DASH, i);
+  }
+
+  // Read month
+  ++i;
+  if ((r = read_two_digit_number(&out->month, 1, 12, str + i)).status) {
+    return result(r.status, i + r.count);
+  }
+
+  // Read month-day delimiter
+  i += r.count;
+  if (str[i] != '-') {
+    return result(EXESS_EXPECTED_DASH, i);
+  }
+
+  // Read day
+  ++i;
+  if ((r = read_two_digit_number(&out->day, 1, 31, str + i)).status) {
+    return result(r.status, i + r.count);
+  }
+
+  // Check that day is in range
+  i += r.count;
+  if (out->day > days_in_month(out->year, out->month)) {
+    return result(EXESS_OUT_OF_RANGE, i);
+  }
+
+  return result(EXESS_SUCCESS, i);
+}
+
+ExessResult
+exess_read_date(ExessDate* const out, const char* const str)
+{
+  memset(out, 0, sizeof(*out));
+
+  // Read YYYY-MM-DD numbers
+  size_t      i = skip_whitespace(str);
+  ExessResult r = read_date_numbers(out, str + i);
+
+  i += r.count;
+  if (r.status || is_end(str[i])) {
+    out->zone.quarter_hours = EXESS_LOCAL;
+    return result(r.status, i);
+  }
+
+  // Read timezone
+  r = exess_read_timezone(&out->zone, str + i);
+
+  return result(r.status, i + r.count);
+}
+
+ExessResult
+exess_write_date(const ExessDate value, const size_t buf_size, char* const buf)
+{
+  if (value.month < 1 || value.month > 12 || value.day < 1 || value.day > 31) {
+    return end_write(EXESS_BAD_VALUE, buf_size, buf, 0);
+  }
+
+  ExessResult r = write_year_number(value.year, buf_size, buf);
+  size_t      o = r.count;
+  if (r.status) {
+    return end_write(r.status, buf_size, buf, o);
+  }
+
+  o += write_char('-', buf_size, buf, o);
+  o += write_two_digit_number(value.month, buf_size, buf, o);
+  o += write_char('-', buf_size, buf, o);
+  o += write_two_digit_number(value.day, buf_size, buf, o);
+
+  r = write_timezone(value.zone, buf_size, buf, o);
+
+  return end_write(r.status, buf_size, buf, o + r.count);
+}