From 50d117cb76883735faa8864c4978b5819cb167bd Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Tue, 22 Mar 2022 18:46:20 -0400
Subject: datetime, formats: Conform to strptime() space req

---
diff --git a/TODO b/TODO
index 56d1f3e..b8f4d77 100644
--- a/TODO
+++ b/TODO
@@ -1,6 +1,3 @@
-spaces between specifiers in strptime() formats -- strftime()?
-	format printing: copy format to another buffer, skipping certain char
-	parsing: copy format one char at a time, changing placeholder to space
 test with other libc's (newlib? musl? fbsd? obsd?)
 `./@ 7:00 PM` doesn't work with musl strptime()
 test other times
diff --git a/src/datetime.c b/src/datetime.c
index 8f5051d..f7cdb89 100644
--- a/src/datetime.c
+++ b/src/datetime.c
@@ -43,6 +43,31 @@ static struct tm DATETIME_EPOCH_ = {
 };
 
 static void
+_datetime_buf_cpy_p(char *dst, const char *src)
+{
+	for (; *src != '\0'; ++src, ++dst) {
+		if (*src == '^') {
+			*dst = ' ';
+		} else {
+			*dst = *src;
+		}
+	}
+	*dst = '\0';
+}
+
+static void
+_datetime_buf_cpy_f(char *dst, const char *src)
+{
+	for (; *src != '\0'; ++src, ++dst) {
+		if (*src == '^') {
+			++src;
+		}
+		*dst = *src;
+	}
+	*dst = '\0';
+}
+
+static void
 _datetime_reset_tm(struct tm *tm)
 {
 	tm->tm_year  = INT_MIN;
@@ -142,7 +167,7 @@ datetime_parse(struct tm *now_tm, const char *input, time_t *arg_sec)
 	sec = *arg_sec;  /* GCC is dumb. */
 	got = false;
 	for (t = 0; t < sizeof(FORMATS_TIME) / sizeof(FORMATS_TIME[0]) ; ++t) {
-		memcpy(fmt_buf, FORMATS_TIME[t], time_fmt_len + 1);
+		_datetime_buf_cpy_p(fmt_buf, FORMATS_TIME[t]);
 		_datetime_reset_tm(&arg_tm);
 		end = strptime(input, fmt_buf, &arg_tm);
 		if (end != NULL && *end == '\0') {
@@ -159,11 +184,11 @@ datetime_parse(struct tm *now_tm, const char *input, time_t *arg_sec)
 		if (FORMATS_DATE[d][0] == '\0') {
 			break;
 		}
-		memcpy(fmt_buf, FORMATS_DATE[d], date_fmt_len + 1);
+		_datetime_buf_cpy_p(fmt_buf, FORMATS_DATE[d]);
 		for (t = 0; t < sizeof(FORMATS_TIME) / sizeof(FORMATS_TIME[0]);
 				++t) {
-			memcpy(fmt_buf + date_fmt_len, FORMATS_TIME[t],
-					time_fmt_len + 1);
+			_datetime_buf_cpy_p(fmt_buf + date_fmt_len,
+					FORMATS_TIME[t]);
 			_datetime_reset_tm(&arg_tm);
 			end = strptime(input, fmt_buf, &arg_tm);
 			if (end != NULL && *end == '\0') {
@@ -178,14 +203,14 @@ datetime_parse(struct tm *now_tm, const char *input, time_t *arg_sec)
 		}
 	}
 	for (t = 0; t < sizeof(FORMATS_TIME) / sizeof(FORMATS_TIME[0]); ++t) {
-		memcpy(fmt_buf, FORMATS_TIME[t], time_fmt_len + 1);
+		_datetime_buf_cpy_p(fmt_buf, FORMATS_TIME[t]);
 		for (d = 0; d < sizeof(FORMATS_DATE) / sizeof(FORMATS_DATE[0]);
 				++d) {
 			if (FORMATS_DATE[d][0] == '\0') {
 				break;
 			}
-			memcpy(fmt_buf + time_fmt_len, FORMATS_DATE[d],
-					date_fmt_len + 1);
+			_datetime_buf_cpy_p(fmt_buf + time_fmt_len,
+					FORMATS_DATE[d]);
 			_datetime_reset_tm(&arg_tm);
 			end = strptime(input, fmt_buf, &arg_tm);
 			if (end != NULL && *end == '\0') {
@@ -200,7 +225,7 @@ datetime_parse(struct tm *now_tm, const char *input, time_t *arg_sec)
 		}
 	}
 	for (d = 0; d < sizeof(FORMATS_MISC) / sizeof(FORMATS_MISC[0]) ; ++d) {
-		memcpy(fmt_buf, FORMATS_MISC[d], misc_fmt_len + 1);
+		_datetime_buf_cpy_p(fmt_buf, FORMATS_MISC[d]);
 		_datetime_reset_tm(&arg_tm);
 		end = strptime(input, fmt_buf, &arg_tm);
 		if (end != NULL && *end == '\0') {
@@ -280,10 +305,12 @@ _datetime_strftime(const char *fmts[], const struct tm *tm, char **out,
 		++*i;
 	}
 
+	_datetime_buf_cpy_f(*out, fmts[*i]);
+
 	resized = 0;
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
-	while (strftime(*buf, *buf_sz, fmts[*i], tm) == 0) {
+	while (strftime(*buf, *buf_sz, *out, tm) == 0) {
 #pragma GCC diagnostic pop
 		++*buf_sz;
 		*buf = realloc(*buf, *buf_sz * sizeof(**buf));
diff --git a/src/formats.h b/src/formats.h
index f4caccd..262912e 100644
--- a/src/formats.h
+++ b/src/formats.h
@@ -25,6 +25,16 @@
  *
  * All of the format strings in each array must be padded with spaces to be of
  * equal lengths.
+ *
+ * Conversion specifications are used by both strptime() and strftime().  As
+ * required by the former function, there shall be "white-space or other non-
+ * alphanumeric characters between any two conversion specifications unless all
+ * of the adjacent conversion specifications convert a known, fixed number of
+ * characters." [POSIX]  The "^" character may be used to separate conversion
+ * specifications that should be separated (by a space) when parsing and
+ * adjacent when formatting for printing.  For example, " %I^%M %p " will be
+ * changed to " %I %M %p " when parsing and to " %I%M %p " when formatting for
+ * printing.
  */
 
 static const char *FORMATS_DATE[] = {
@@ -220,10 +230,10 @@ static const char *FORMATS_TIME[] = {
 	" %H.%M.%S    ",  /* 19.00.01   */
 	" %I.%M %p    ",  /* 7.00 PM    */
 	" %H.%M       ",  /* 19.00      */
-	" %I%M%S %p   ",  /* 70001 PM   */
-	" %H%M%S      ",  /* 190001     */
-	" %I%M %p     ",  /* 700 PM     */
-	" %H%M        ",  /* 1900       */
+	" %I^%M^%S %p ",  /* 70001 PM   */
+	" %H^%M^%S    ",  /* 190001     */
+	" %I^%M %p    ",  /* 700 PM     */
+	" %H^%M       ",  /* 1900       */
 };
 
 static const char *FORMATS_MISC[] = {
@@ -231,13 +241,13 @@ static const char *FORMATS_MISC[] = {
 	" %Y-%m-%dT%H:%M:%S    ",
 	" %Y-%m-%dT%H:%M       ",
 	/* ISO 8601: 19691231 delimited by "T" */
-	" %Y%m%dT%H%M%S        ",
-	" %Y%m%dT%H%M          ",
+	" %Y^%m^%dT%H^%M^%S    ",
+	" %Y^%m^%dT%H^%M       ",
 	/* 19691231 */
-	" %Y%m%d %I%M%S %p     ",
-	" %Y%m%d %H%M%S        ",
-	" %Y%m%d %I%M %p       ",
-	" %Y%m%d %H%M          ",
+	" %Y^%m^%d %I^%M^%S %p ",
+	" %Y^%m^%d %H^%M^%S    ",
+	" %Y^%m^%d %I^%M %p    ",
+	" %Y^%m^%d %H^%M       ",
 	/* Wed Dec 31 19:00:01 1969 */
 	" %a %b %d %H:%M:%S %Y ",
 };
--
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