pkarashchenko commented on code in PR #6029:
URL: https://github.com/apache/incubator-nuttx/pull/6029#discussion_r848643830
##########
libs/libc/time/lib_strptime.c:
##########
@@ -0,0 +1,540 @@
+/****************************************************************************
+ * libs/libc/time/lib_strptime.c
+ *
+ * $OpenBSD: strptime.c,v 1.11 2005/08/08 08:05:38 espie Exp $
+ * $NetBSD: strptime.c,v 1.12 1998/01/20 21:39:40 mycroft Exp $
+ *
+ * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code was contributed to The NetBSD Foundation by Klaus Klein.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the NetBSD
+ * Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+#include <nuttx/config.h>
+
+#include <ctype.h>
+#include <locale.h>
+#include <strings.h>
+#include <time.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define TM_YEAR_BASE 1900
+#define _ctloc(x) (_defaulttimelocale.x)
+
+/* We do not implement alternate representations. However, we always
+ * check whether a given modifier is allowed for a certain conversion.
+ */
+
+#define _ALT_E 0x01
+#define _ALT_O 0x02
+#define _LEGAL_ALT(x) { if (alt_format & ~(x)) return (0); }
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct
+{
+ const char *abday[7];
+ const char *day[7];
+ const char *abmon[12];
+ const char *mon[12];
+ const char *am_pm[2];
+ const char *d_t_fmt;
+ const char *d_fmt;
+ const char *t_fmt;
+ const char *t_fmt_ampm;
+} _defaulttimelocale =
+{
+ {
+ "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
+ },
+ {
+ "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
+ "Friday", "Saturday"
+ },
+ {
+ "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+ "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+ },
+ {
+ "January", "February", "March", "April", "May", "June", "July",
+ "August", "September", "October", "November", "December"
+ },
+ {
+ "AM", "PM"
+ },
+ "%a %b %d %H:%M:%S %Y",
+ "%m/%d/%y",
+ "%H:%M:%S",
+ "%I:%M:%S %p"
+};
+
+struct century_relyear
+{
+ int century;
+ int relyear;
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static int _conv_num(const unsigned char **buf, int *dest,
+ int llim, int ulim)
+{
+ int result = 0;
+ int rulim = ulim;
+
+ while (isspace(**buf))
+ (*buf)++;
+
+ if (**buf < '0' || **buf > '9')
+ {
+ return (0);
+ }
+
+ /* we use rulim to break out of the loop when we run out of digits */
+
+ do
+ {
+ result *= 10;
+ result += *(*buf)++ - '0';
+ rulim /= 10;
+ }
+ while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
+
+ if (result < llim || result > ulim)
+ {
+ return (0);
+ }
+
+ *dest = result;
+ return (1);
+}
+
+static unsigned char * _strptime(const unsigned char *buf,
+ const char *fmt,
+ struct tm *tm,
+ struct century_relyear *cr)
+{
+ unsigned char c;
+ const unsigned char *bp;
+ size_t len = 0;
+ int alt_format;
+ int i;
+
+ bp = (unsigned char *)buf;
+ while ((c = *fmt) != '\0')
+ {
+ /* Clear `alternate' modifier prior to new conversion. */
+
+ alt_format = 0;
+
+ /* Eat up white-space. */
+
+ if (isspace(c))
+ {
+ while (isspace(*bp))
+ bp++;
+
+ fmt++;
+ continue;
+ }
+
+ if ((c = *fmt++) != '%')
+ {
+ goto literal;
+ }
+
+ again:
+ switch (c = *fmt++)
+ {
+ case '%': /* "%%" is converted to "%". */
+ literal:
+ if (c != *bp++)
+ return (NULL);
+
+ break;
+
+ /* "Alternative" modifiers. Just set the appropriate flag
+ * and start over again.
+ */
+
+ case 'E': /* "%E?" alternative conversion modifier. */
+ _LEGAL_ALT(0);
+ alt_format |= _ALT_E;
+ goto again;
+
+ case 'O': /* "%O?" alternative conversion modifier. */
+ _LEGAL_ALT(0);
+ alt_format |= _ALT_O;
+ goto again;
+
+ /* "Complex" conversion rules, implemented through recursion. */
+
+ case 'c': /* Date and time, using the locale's format. */
+ _LEGAL_ALT(_ALT_E);
+ if (!(bp = _strptime(bp, _ctloc(d_t_fmt), tm, cr)))
+ return (NULL);
+ break;
+
+ case 'D': /* The date as "%m/%d/%y". */
+ _LEGAL_ALT(0);
+ if (!(bp = _strptime(bp, "%m/%d/%y", tm, cr)))
+ return (NULL);
+ break;
+
+ case 'R': /* The time as "%H:%M". */
+ _LEGAL_ALT(0);
+ if (!(bp = _strptime(bp, "%H:%M", tm, cr)))
+ return (NULL);
+ break;
+
+ case 'r': /* The time as "%I:%M:%S %p". */
+ _LEGAL_ALT(0);
+ if (!(bp = _strptime(bp, "%I:%M:%S %p", tm, cr)))
+ return (NULL);
+ break;
+
+ case 'T': /* The time as "%H:%M:%S". */
+ _LEGAL_ALT(0);
+ if (!(bp = _strptime(bp, "%H:%M:%S", tm, cr)))
+ return (NULL);
+ break;
+
+ case 'X': /* The time, using the locale's format. */
+ _LEGAL_ALT(_ALT_E);
+ if (!(bp = _strptime(bp, _ctloc(t_fmt), tm, cr)))
+ return (NULL);
+ break;
+
+ case 'x': /* The date, using the locale's format. */
+ _LEGAL_ALT(_ALT_E);
+ if (!(bp = _strptime(bp, _ctloc(d_fmt), tm, cr)))
+ return (NULL);
+ break;
+
+ /* "Elementary" conversion rules. */
+
+ case 'A': /* The day of week, using the locale's form. */
+ case 'a':
+ _LEGAL_ALT(0);
+ for (i = 0; i < 7; i++)
+ {
+ /* Full name. */
+
+ len = strlen(_ctloc(day[i]));
+ if (strncasecmp(_ctloc(day[i]),
+ (const char *)bp, len) == 0)
+ break;
+
+ /* Abbreviated name. */
+
+ len = strlen(_ctloc(abday[i]));
+ if (strncasecmp(_ctloc(abday[i]),
+ (const char *)bp, len) == 0)
+ break;
+ }
+
+ /* Nothing matched. */
+
+ if (i == 7)
+ return (NULL);
+
+ tm->tm_wday = i;
+ bp += len;
+ break;
+
+ case 'B': /* The month, using the locale's form. */
+ case 'b':
+ case 'h':
+ _LEGAL_ALT(0);
+ for (i = 0; i < 12; i++)
+ {
+ /* Full name. */
+
+ len = strlen(_ctloc(mon[i]));
+ if (strncasecmp(_ctloc(mon[i]),
+ (const char *)bp, len) == 0)
+ break;
+
+ /* Abbreviated name. */
+
+ len = strlen(_ctloc(abmon[i]));
+ if (strncasecmp(_ctloc(abmon[i]),
+ (const char *)bp, len) == 0)
+ break;
+ }
+
+ /* Nothing matched. */
+
+ if (i == 12)
+ return (NULL);
+
+ tm->tm_mon = i;
+ bp += len;
+ break;
+
+ case 'C': /* The century number. */
+ _LEGAL_ALT(_ALT_E);
+ if (!(_conv_num(&bp, &i, 0, 99)))
+ return (NULL);
+
+ cr->century = i * 100;
+ break;
+
+ case 'd': /* The day of month. */
+ case 'e':
+ _LEGAL_ALT(_ALT_O);
+ if (!(_conv_num(&bp, &tm->tm_mday, 1, 31)))
+ return (NULL);
+ break;
+
+ case 'k': /* The hour (24-hour clock representation). */
+ _LEGAL_ALT(0);
+
+ /* FALLTHROUGH */
+
+ case 'H':
+ _LEGAL_ALT(_ALT_O);
+ if (!(_conv_num(&bp, &tm->tm_hour, 0, 23)))
+ return (NULL);
+ break;
+
+ case 'l': /* The hour (12-hour clock representation). */
+ _LEGAL_ALT(0);
+
+ /* FALLTHROUGH */
+
+ case 'I':
+ _LEGAL_ALT(_ALT_O);
+ if (!(_conv_num(&bp, &tm->tm_hour, 1, 12)))
+ return (NULL);
+ break;
+
+ case 'j': /* The day of year. */
+ _LEGAL_ALT(0);
+ if (!(_conv_num(&bp, &tm->tm_yday, 1, 366)))
+ return (NULL);
+ tm->tm_yday--;
+ break;
+
+ case 'M': /* The minute. */
+ _LEGAL_ALT(_ALT_O);
+ if (!(_conv_num(&bp, &tm->tm_min, 0, 59)))
+ return (NULL);
+ break;
+
+ case 'm': /* The month. */
+ _LEGAL_ALT(_ALT_O);
+ if (!(_conv_num(&bp, &tm->tm_mon, 1, 12)))
+ return (NULL);
+ tm->tm_mon--;
+ break;
+
+ case 'p': /* The locale's equivalent of AM/PM. */
+ _LEGAL_ALT(0);
+
+ /* AM? */
+
+ len = strlen(_ctloc(am_pm[0]));
+ if (strncasecmp(_ctloc(am_pm[0]), (const char *)bp, len) == 0)
+ {
+ if (tm->tm_hour > 12) /* i.e., 13:00 AM ?! */
+ return (NULL);
+ else if (tm->tm_hour == 12)
+ tm->tm_hour = 0;
+
+ bp += len;
+ break;
+ }
+
+ /* PM? */
+
+ len = strlen(_ctloc(am_pm[1]));
+ if (strncasecmp(_ctloc(am_pm[1]), (const char *)bp, len) == 0)
+ {
+ if (tm->tm_hour > 12) /* i.e., 13:00 PM ?! */
+ return (NULL);
+ else if (tm->tm_hour < 12)
+ tm->tm_hour += 12;
+
+ bp += len;
+ break;
+ }
+
+ /* Nothing matched. */
+
+ return (NULL);
+
+ case 'S': /* The seconds. */
+ _LEGAL_ALT(_ALT_O);
+ if (!(_conv_num(&bp, &tm->tm_sec, 0, 61)))
+ return (NULL);
+ break;
+
+ case 'U': /* The week of year, beginning on sunday. */
+ case 'W': /* The week of year, beginning on monday. */
+ _LEGAL_ALT(_ALT_O);
+ /* XXX This is bogus, as we can not assume any valid
+ * information present in the tm structure at this
+ * point to calculate a real value, so just check the
+ * range for now.
+ */
+
+ if (!(_conv_num(&bp, &i, 0, 53)))
+ return (NULL);
+ break;
+
+ case 'w': /* The day of week, beginning on sunday. */
+ _LEGAL_ALT(_ALT_O);
+ if (!(_conv_num(&bp, &tm->tm_wday, 0, 6)))
+ return (NULL);
+ break;
+
+ case 'Y': /* The year. */
+ _LEGAL_ALT(_ALT_E);
+ if (!(_conv_num(&bp, &i, 0, 9999)))
+ return (NULL);
+
+ cr->relyear = -1;
+ tm->tm_year = i - TM_YEAR_BASE;
+ break;
+
+ case 'y': /* The year within the century (2 digits). */
+ _LEGAL_ALT(_ALT_E | _ALT_O);
+ if (!(_conv_num(&bp, &cr->relyear, 0, 99)))
+ return (NULL);
+ break;
+
+ /* Miscellaneous conversions. */
+
+ case 'n': /* Any kind of white-space. */
+ case 't':
+ _LEGAL_ALT(0);
+ while (isspace(*bp))
+ bp++;
+ break;
+
+ default: /* Unknown/unsupported conversion. */
+ return (NULL);
+ }
+ }
+
+ /* We need to evaluate the two digit year spec (%y)
+ * last as we can get a century spec (%C) at any time.
+ */
+
+ if (cr->relyear != -1)
+ {
+ if (cr->century == TM_YEAR_BASE)
+ {
+ if (cr->relyear <= 68)
+ tm->tm_year = cr->relyear + 2000 - TM_YEAR_BASE;
+ else
+ tm->tm_year = cr->relyear + 1900 - TM_YEAR_BASE;
+ }
+ else
+ {
+ tm->tm_year = cr->relyear + cr->century - TM_YEAR_BASE;
+ }
+ }
+
+ return (unsigned char *)bp;
Review Comment:
I saw that the POSIX prototype returns `char *` but not `const char*`, so it
seems we have to accept this inconsistency.
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