/src/CMake/Utilities/cmlibarchive/libarchive/archive_parse_date.c

Source
/*
 * This code is in the public domain and has no copyright.
 *
 * This is a plain C recursive-descent translation of an old
 * public-domain YACC grammar that has been used for parsing dates in
 * very many open-source projects.
 *
 * Since the original authors were generous enough to donate their
 * work to the public domain, I feel compelled to match their
 * generosity.
 *
 * Tim Kientzle, February 2009.
 */

/*
 * Header comment from original getdate.y:
 */

/*
**  Originally written by Steven M. Bellovin <smb@research.att.com> while
**  at the University of North Carolina at Chapel Hill.  Later tweaked by
**  a couple of people on Usenet.  Completely overhauled by Rich $alz
**  <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990;
**
**  This grammar has 10 shift/reduce conflicts.
**
**  This code is in the public domain and has no copyright.
*/

#ifndef CM_PARSE_DATE
#include "archive_platform.h"
#endif

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "archive.h"

/* Basic time units. */
#define EPOCH   1970
#define MINUTE    (60L)
#define HOUR    (60L * MINUTE)
#define DAY   (24L * HOUR)

/* Daylight-savings mode:  on, off, or not yet known. */
enum DSTMODE { DSTon, DSToff, DSTmaybe };
/* Meridian:  am or pm. */
enum { tAM, tPM };
/* Token types returned by nexttoken() */
enum { tAGO = 260, tDAY, tDAYZONE, tAMPM, tMONTH, tMONTH_UNIT, tSEC_UNIT,
       tUNUMBER, tZONE, tDST };
struct token { int token; time_t value; };

/*
 * Parser state.
 */
struct gdstate {
  struct token *tokenp; /* Pointer to next token. */
  /* HaveXxxx counts how many of this kind of phrase we've seen;
   * it's a fatal error to have more than one time, zone, day,
   * or date phrase. */
  int HaveYear;
  int HaveMonth;
  int HaveDay;
  int HaveWeekDay; /* Day of week */
  int HaveTime; /* Hour/minute/second */
  int HaveZone; /* timezone and/or DST info */
  int HaveRel; /* time offset; we can have more than one */
  /* Absolute time values. */
  time_t  Timezone;  /* Seconds offset from GMT */
  time_t  Day;
  time_t  Hour;
  time_t  Minutes;
  time_t  Month;
  time_t  Seconds;
  time_t  Year;
  /* DST selection */
  enum DSTMODE  DSTmode;
  /* Day of week accounting, e.g., "3rd Tuesday" */
  time_t  DayOrdinal; /* "3" in "3rd Tuesday" */
  time_t  DayNumber; /* "Tuesday" in "3rd Tuesday" */
  /* Relative time values: hour/day/week offsets are measured in
   * seconds, month/year are counted in months. */
  time_t  RelMonth;
  time_t  RelSeconds;
};

/*
 * A series of functions that recognize certain common time phrases.
 * Each function returns 1 if it managed to make sense of some of the
 * tokens, zero otherwise.
 */

/*
 *  hour:minute or hour:minute:second with optional AM, PM, or numeric
 *  timezone offset
 */
static int
timephrase(struct gdstate *gds)
{
  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == ':'
      && gds->tokenp[2].token == tUNUMBER
      && gds->tokenp[3].token == ':'
      && gds->tokenp[4].token == tUNUMBER) {
    /* "12:14:18" or "22:08:07" */
    ++gds->HaveTime;
    gds->Hour = gds->tokenp[0].value;
    gds->Minutes = gds->tokenp[2].value;
    gds->Seconds = gds->tokenp[4].value;
    gds->tokenp += 5;
  }
  else if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == ':'
      && gds->tokenp[2].token == tUNUMBER) {
    /* "12:14" or "22:08" */
    ++gds->HaveTime;
    gds->Hour = gds->tokenp[0].value;
    gds->Minutes = gds->tokenp[2].value;
    gds->Seconds = 0;
    gds->tokenp += 3;
  }
  else if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == tAMPM) {
    /* "7" is a time if it's followed by "am" or "pm" */
    ++gds->HaveTime;
    gds->Hour = gds->tokenp[0].value;
    gds->Minutes = gds->Seconds = 0;
    /* We'll handle the AM/PM below. */
    gds->tokenp += 1;
  } else {
    /* We can't handle this. */
    return 0;
  }

  if (gds->tokenp[0].token == tAMPM) {
    /* "7:12pm", "12:20:13am" */
    if (gds->Hour == 12)
      gds->Hour = 0;
    if (gds->tokenp[0].value == tPM)
      gds->Hour += 12;
    gds->tokenp += 1;
  }
  if (gds->tokenp[0].token == '+'
      && gds->tokenp[1].token == tUNUMBER) {
    /* "7:14+0700" */
    gds->HaveZone++;
    gds->DSTmode = DSToff;
    gds->Timezone = - ((gds->tokenp[1].value / 100) * HOUR
        + (gds->tokenp[1].value % 100) * MINUTE);
    gds->tokenp += 2;
  }
  if (gds->tokenp[0].token == '-'
      && gds->tokenp[1].token == tUNUMBER) {
    /* "19:14:12-0530" */
    gds->HaveZone++;
    gds->DSTmode = DSToff;
    gds->Timezone = + ((gds->tokenp[1].value / 100) * HOUR
        + (gds->tokenp[1].value % 100) * MINUTE);
    gds->tokenp += 2;
  }
  return 1;
}

/*
 * Timezone name, possibly including DST.
 */
static int
zonephrase(struct gdstate *gds)
{
  if (gds->tokenp[0].token == tZONE
      && gds->tokenp[1].token == tDST) {
    gds->HaveZone++;
    gds->Timezone = gds->tokenp[0].value;
    gds->DSTmode = DSTon;
    gds->tokenp += 1;
    return 1;
  }

  if (gds->tokenp[0].token == tZONE) {
    gds->HaveZone++;
    gds->Timezone = gds->tokenp[0].value;
    gds->DSTmode = DSToff;
    gds->tokenp += 1;
    return 1;
  }

  if (gds->tokenp[0].token == tDAYZONE) {
    gds->HaveZone++;
    gds->Timezone = gds->tokenp[0].value;
    gds->DSTmode = DSTon;
    gds->tokenp += 1;
    return 1;
  }
  return 0;
}

/*
 * Year/month/day in various combinations.
 */
static int
datephrase(struct gdstate *gds)
{
  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == '/'
      && gds->tokenp[2].token == tUNUMBER
      && gds->tokenp[3].token == '/'
      && gds->tokenp[4].token == tUNUMBER) {
    gds->HaveYear++;
    gds->HaveMonth++;
    gds->HaveDay++;
    if (gds->tokenp[0].value >= 13) {
      /* First number is big:  2004/01/29, 99/02/17 */
      gds->Year = gds->tokenp[0].value;
      gds->Month = gds->tokenp[2].value;
      gds->Day = gds->tokenp[4].value;
    } else if ((gds->tokenp[4].value >= 13)
        || (gds->tokenp[2].value >= 13)) {
      /* Last number is big:  01/07/98 */
      /* Middle number is big:  01/29/04 */
      gds->Month = gds->tokenp[0].value;
      gds->Day = gds->tokenp[2].value;
      gds->Year = gds->tokenp[4].value;
    } else {
      /* No significant clues: 02/03/04 */
      gds->Month = gds->tokenp[0].value;
      gds->Day = gds->tokenp[2].value;
      gds->Year = gds->tokenp[4].value;
    }
    gds->tokenp += 5;
    return 1;
  }

  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == '/'
      && gds->tokenp[2].token == tUNUMBER) {
    /* "1/15" */
    gds->HaveMonth++;
    gds->HaveDay++;
    gds->Month = gds->tokenp[0].value;
    gds->Day = gds->tokenp[2].value;
    gds->tokenp += 3;
    return 1;
  }

  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == '-'
      && gds->tokenp[2].token == tUNUMBER
      && gds->tokenp[3].token == '-'
      && gds->tokenp[4].token == tUNUMBER) {
    /* ISO 8601 format.  yyyy-mm-dd.  */
    gds->HaveYear++;
    gds->HaveMonth++;
    gds->HaveDay++;
    gds->Year = gds->tokenp[0].value;
    gds->Month = gds->tokenp[2].value;
    gds->Day = gds->tokenp[4].value;
    gds->tokenp += 5;
    return 1;
  }

  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == '-'
      && gds->tokenp[2].token == tMONTH
      && gds->tokenp[3].token == '-'
      && gds->tokenp[4].token == tUNUMBER) {
    gds->HaveYear++;
    gds->HaveMonth++;
    gds->HaveDay++;
    if (gds->tokenp[0].value > 31) {
      /* e.g. 1992-Jun-17 */
      gds->Year = gds->tokenp[0].value;
      gds->Month = gds->tokenp[2].value;
      gds->Day = gds->tokenp[4].value;
    } else {
      /* e.g. 17-JUN-1992.  */
      gds->Day = gds->tokenp[0].value;
      gds->Month = gds->tokenp[2].value;
      gds->Year = gds->tokenp[4].value;
    }
    gds->tokenp += 5;
    return 1;
  }

  if (gds->tokenp[0].token == tMONTH
      && gds->tokenp[1].token == tUNUMBER
      && gds->tokenp[2].token == ','
      && gds->tokenp[3].token == tUNUMBER) {
    /* "June 17, 2001" */
    gds->HaveYear++;
    gds->HaveMonth++;
    gds->HaveDay++;
    gds->Month = gds->tokenp[0].value;
    gds->Day = gds->tokenp[1].value;
    gds->Year = gds->tokenp[3].value;
    gds->tokenp += 4;
    return 1;
  }

  if (gds->tokenp[0].token == tMONTH
      && gds->tokenp[1].token == tUNUMBER) {
    /* "May 3" */
    gds->HaveMonth++;
    gds->HaveDay++;
    gds->Month = gds->tokenp[0].value;
    gds->Day = gds->tokenp[1].value;
    gds->tokenp += 2;
    return 1;
  }

  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == tMONTH
      && gds->tokenp[2].token == tUNUMBER) {
    /* "12 Sept 1997" */
    gds->HaveYear++;
    gds->HaveMonth++;
    gds->HaveDay++;
    gds->Day = gds->tokenp[0].value;
    gds->Month = gds->tokenp[1].value;
    gds->Year = gds->tokenp[2].value;
    gds->tokenp += 3;
    return 1;
  }

  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == tMONTH) {
    /* "12 Sept" */
    gds->HaveMonth++;
    gds->HaveDay++;
    gds->Day = gds->tokenp[0].value;
    gds->Month = gds->tokenp[1].value;
    gds->tokenp += 2;
    return 1;
  }

  return 0;
}

/*
 * Relative time phrase: "tomorrow", "yesterday", "+1 hour", etc.
 */
static int
relunitphrase(struct gdstate *gds)
{
  if (gds->tokenp[0].token == '-'
      && gds->tokenp[1].token == tUNUMBER
      && gds->tokenp[2].token == tSEC_UNIT) {
    /* "-3 hours" */
    gds->HaveRel++;
    gds->RelSeconds -= gds->tokenp[1].value * gds->tokenp[2].value;
    gds->tokenp += 3;
    return 1;
  }
  if (gds->tokenp[0].token == '+'
      && gds->tokenp[1].token == tUNUMBER
      && gds->tokenp[2].token == tSEC_UNIT) {
    /* "+1 minute" */
    gds->HaveRel++;
    gds->RelSeconds += gds->tokenp[1].value * gds->tokenp[2].value;
    gds->tokenp += 3;
    return 1;
  }
  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == tSEC_UNIT) {
    /* "1 day" */
    gds->HaveRel++;
    gds->RelSeconds += gds->tokenp[0].value * gds->tokenp[1].value;
    gds->tokenp += 2;
    return 1;
  }
  if (gds->tokenp[0].token == '-'
      && gds->tokenp[1].token == tUNUMBER
      && gds->tokenp[2].token == tMONTH_UNIT) {
    /* "-3 months" */
    gds->HaveRel++;
    gds->RelMonth -= gds->tokenp[1].value * gds->tokenp[2].value;
    gds->tokenp += 3;
    return 1;
  }
  if (gds->tokenp[0].token == '+'
      && gds->tokenp[1].token == tUNUMBER
      && gds->tokenp[2].token == tMONTH_UNIT) {
    /* "+5 years" */
    gds->HaveRel++;
    gds->RelMonth += gds->tokenp[1].value * gds->tokenp[2].value;
    gds->tokenp += 3;
    return 1;
  }
  if (gds->tokenp[0].token == tUNUMBER
      && gds->tokenp[1].token == tMONTH_UNIT) {
    /* "2 years" */
    gds->HaveRel++;
    gds->RelMonth += gds->tokenp[0].value * gds->tokenp[1].value;
    gds->tokenp += 2;
    return 1;
  }
  if (gds->tokenp[0].token == tSEC_UNIT) {
    /* "now", "tomorrow" */
    gds->HaveRel++;
    gds->RelSeconds += gds->tokenp[0].value;
    gds->tokenp += 1;
    return 1;
  }
  if (gds->tokenp[0].token == tMONTH_UNIT) {
    /* "month" */
    gds->HaveRel++;
    gds->RelMonth += gds->tokenp[0].value;
    gds->tokenp += 1;
    return 1;
  }
  return 0;
}

/*
 * Day of the week specification.
 */
static int
dayphrase(struct gdstate *gds)
{
  if (gds->tokenp[0].token == tDAY) {
    /* "tues", "wednesday," */
    gds->HaveWeekDay++;
    gds->DayOrdinal = 1;
    gds->DayNumber = gds->tokenp[0].value;
    gds->tokenp += 1;
    if (gds->tokenp[0].token == ',')
      gds->tokenp += 1;
    return 1;
  }
  if (gds->tokenp[0].token == tUNUMBER
    && gds->tokenp[1].token == tDAY) {
    /* "second tues" "3 wed" */
    gds->HaveWeekDay++;
    gds->DayOrdinal = gds->tokenp[0].value;
    gds->DayNumber = gds->tokenp[1].value;
    gds->tokenp += 2;
    return 1;
  }
  return 0;
}

/*
 * Try to match a phrase using one of the above functions.
 * This layer also deals with a couple of generic issues.
 */
static int
phrase(struct gdstate *gds)
{
  if (timephrase(gds))
    return 1;
  if (zonephrase(gds))
    return 1;
  if (datephrase(gds))
    return 1;
  if (dayphrase(gds))
    return 1;
  if (relunitphrase(gds)) {
    if (gds->tokenp[0].token == tAGO) {
      gds->RelSeconds = -gds->RelSeconds;
      gds->RelMonth = -gds->RelMonth;
      gds->tokenp += 1;
    }
    return 1;
  }

  /* Bare numbers sometimes have meaning. */
  if (gds->tokenp[0].token == tUNUMBER) {
    if (gds->HaveTime && !gds->HaveYear && !gds->HaveRel) {
      gds->HaveYear++;
      gds->Year = gds->tokenp[0].value;
      gds->tokenp += 1;
      return 1;
    }

    if(gds->tokenp[0].value > 10000) {
      /* "20040301" */
      gds->HaveYear++;
      gds->HaveMonth++;
      gds->HaveDay++;
      gds->Day= (gds->tokenp[0].value)%100;
      gds->Month= (gds->tokenp[0].value/100)%100;
      gds->Year = gds->tokenp[0].value/10000;
      gds->tokenp += 1;
      return 1;
    }

    if (gds->tokenp[0].value < 24) {
      gds->HaveTime++;
      gds->Hour = gds->tokenp[0].value;
      gds->Minutes = 0;
      gds->Seconds = 0;
      gds->tokenp += 1;
      return 1;
    }

    if ((gds->tokenp[0].value / 100 < 24)
        && (gds->tokenp[0].value % 100 < 60)) {
      /* "513" is same as "5:13" */
      gds->Hour = gds->tokenp[0].value / 100;
      gds->Minutes = gds->tokenp[0].value % 100;
      gds->Seconds = 0;
      gds->tokenp += 1;
      return 1;
    }
  }

  return 0;
}

/*
 * A dictionary of time words.
 */
static struct LEXICON {
  size_t    abbrev;
  const char  *name;
  int   type;
  time_t    value;
} const TimeWords[] = {
  /* am/pm */
  { 0, "am",    tAMPM,  tAM },
  { 0, "pm",    tAMPM,  tPM },

  /* Month names. */
  { 3, "january",   tMONTH,  1 },
  { 3, "february",  tMONTH,  2 },
  { 3, "march",   tMONTH,  3 },
  { 3, "april",   tMONTH,  4 },
  { 3, "may",   tMONTH,  5 },
  { 3, "june",    tMONTH,  6 },
  { 3, "july",    tMONTH,  7 },
  { 3, "august",    tMONTH,  8 },
  { 3, "september", tMONTH,  9 },
  { 3, "october",   tMONTH, 10 },
  { 3, "november",  tMONTH, 11 },
  { 3, "december",  tMONTH, 12 },

  /* Days of the week. */
  { 2, "sunday",    tDAY, 0 },
  { 3, "monday",    tDAY, 1 },
  { 2, "tuesday",   tDAY, 2 },
  { 3, "wednesday", tDAY, 3 },
  { 2, "thursday",  tDAY, 4 },
  { 2, "friday",    tDAY, 5 },
  { 2, "saturday",  tDAY, 6 },

  /* Timezones: Offsets are in seconds. */
  { 0, "gmt",  tZONE,     0*HOUR }, /* Greenwich Mean */
  { 0, "ut",   tZONE,     0*HOUR }, /* Universal (Coordinated) */
  { 0, "utc",  tZONE,     0*HOUR },
  { 0, "wet",  tZONE,     0*HOUR }, /* Western European */
  { 0, "bst",  tDAYZONE,  0*HOUR }, /* British Summer */
  { 0, "wat",  tZONE,     1*HOUR }, /* West Africa */
  { 0, "at",   tZONE,     2*HOUR }, /* Azores */
  /* { 0, "bst", tZONE, 3*HOUR }, */ /* Brazil Standard: Conflict */
  /* { 0, "gst", tZONE, 3*HOUR }, */ /* Greenland Standard: Conflict*/
  { 0, "nft",  tZONE,     3*HOUR+30*MINUTE }, /* Newfoundland */
  { 0, "nst",  tZONE,     3*HOUR+30*MINUTE }, /* Newfoundland Standard */
  { 0, "ndt",  tDAYZONE,  3*HOUR+30*MINUTE }, /* Newfoundland Daylight */
  { 0, "ast",  tZONE,     4*HOUR }, /* Atlantic Standard */
  { 0, "adt",  tDAYZONE,  4*HOUR }, /* Atlantic Daylight */
  { 0, "est",  tZONE,     5*HOUR }, /* Eastern Standard */
  { 0, "edt",  tDAYZONE,  5*HOUR }, /* Eastern Daylight */
  { 0, "cst",  tZONE,     6*HOUR }, /* Central Standard */
  { 0, "cdt",  tDAYZONE,  6*HOUR }, /* Central Daylight */
  { 0, "mst",  tZONE,     7*HOUR }, /* Mountain Standard */
  { 0, "mdt",  tDAYZONE,  7*HOUR }, /* Mountain Daylight */
  { 0, "pst",  tZONE,     8*HOUR }, /* Pacific Standard */
  { 0, "pdt",  tDAYZONE,  8*HOUR }, /* Pacific Daylight */
  { 0, "yst",  tZONE,     9*HOUR }, /* Yukon Standard */
  { 0, "ydt",  tDAYZONE,  9*HOUR }, /* Yukon Daylight */
  { 0, "hst",  tZONE,     10*HOUR }, /* Hawaii Standard */
  { 0, "hdt",  tDAYZONE,  10*HOUR }, /* Hawaii Daylight */
  { 0, "cat",  tZONE,     10*HOUR }, /* Central Alaska */
  { 0, "ahst", tZONE,     10*HOUR }, /* Alaska-Hawaii Standard */
  { 0, "nt",   tZONE,     11*HOUR }, /* Nome */
  { 0, "idlw", tZONE,     12*HOUR }, /* Intl Date Line West */
  { 0, "cet",  tZONE,     -1*HOUR }, /* Central European */
  { 0, "met",  tZONE,     -1*HOUR }, /* Middle European */
  { 0, "mewt", tZONE,     -1*HOUR }, /* Middle European Winter */
  { 0, "mest", tDAYZONE,  -1*HOUR }, /* Middle European Summer */
  { 0, "swt",  tZONE,     -1*HOUR }, /* Swedish Winter */
  { 0, "sst",  tDAYZONE,  -1*HOUR }, /* Swedish Summer */
  { 0, "fwt",  tZONE,     -1*HOUR }, /* French Winter */
  { 0, "fst",  tDAYZONE,  -1*HOUR }, /* French Summer */
  { 0, "eet",  tZONE,     -2*HOUR }, /* Eastern Eur, USSR Zone 1 */
  { 0, "bt",   tZONE,     -3*HOUR }, /* Baghdad, USSR Zone 2 */
  { 0, "it",   tZONE,     -3*HOUR-30*MINUTE },/* Iran */
  { 0, "zp4",  tZONE,     -4*HOUR }, /* USSR Zone 3 */
  { 0, "zp5",  tZONE,     -5*HOUR }, /* USSR Zone 4 */
  { 0, "ist",  tZONE,     -5*HOUR-30*MINUTE },/* Indian Standard */
  { 0, "zp6",  tZONE,     -6*HOUR }, /* USSR Zone 5 */
  /* { 0, "nst",  tZONE, -6.5*HOUR }, */ /* North Sumatra: Conflict */
  /* { 0, "sst", tZONE, -7*HOUR }, */ /* So Sumatra, USSR 6: Conflict */
  { 0, "wast", tZONE,     -7*HOUR }, /* West Australian Standard */
  { 0, "wadt", tDAYZONE,  -7*HOUR }, /* West Australian Daylight */
  { 0, "jt",   tZONE,     -7*HOUR-30*MINUTE },/* Java (3pm in Cronusland!)*/
  { 0, "cct",  tZONE,     -8*HOUR }, /* China Coast, USSR Zone 7 */
  { 0, "jst",  tZONE,     -9*HOUR }, /* Japan Std, USSR Zone 8 */
  { 0, "cast", tZONE,     -9*HOUR-30*MINUTE },/* Ctrl Australian Std */
  { 0, "cadt", tDAYZONE,  -9*HOUR-30*MINUTE },/* Ctrl Australian Daylt */
  { 0, "east", tZONE,     -10*HOUR }, /* Eastern Australian Std */
  { 0, "eadt", tDAYZONE,  -10*HOUR }, /* Eastern Australian Daylt */
  { 0, "gst",  tZONE,     -10*HOUR }, /* Guam Std, USSR Zone 9 */
  { 0, "nzt",  tZONE,     -12*HOUR }, /* New Zealand */
  { 0, "nzst", tZONE,     -12*HOUR }, /* New Zealand Standard */
  { 0, "nzdt", tDAYZONE,  -12*HOUR }, /* New Zealand Daylight */
  { 0, "idle", tZONE,     -12*HOUR }, /* Intl Date Line East */

  { 0, "dst",  tDST,    0 },

  /* Time units. */
  { 4, "years",   tMONTH_UNIT,  12 },
  { 5, "months",    tMONTH_UNIT,  1 },
  { 9, "fortnights",  tSEC_UNIT,  14 * DAY },
  { 4, "weeks",   tSEC_UNIT,  7 * DAY },
  { 3, "days",    tSEC_UNIT,  DAY },
  { 4, "hours",   tSEC_UNIT,  HOUR },
  { 3, "minutes",   tSEC_UNIT,  MINUTE },
  { 3, "seconds",   tSEC_UNIT,  1 },

  /* Relative-time words. */
  { 0, "tomorrow",  tSEC_UNIT,  DAY },
  { 0, "yesterday", tSEC_UNIT,  -DAY },
  { 0, "today",   tSEC_UNIT,  0 },
  { 0, "now",   tSEC_UNIT,  0 },
  { 0, "last",    tUNUMBER, -1 },
  { 0, "this",    tSEC_UNIT,  0 },
  { 0, "next",    tUNUMBER, 2 },
  { 0, "first",   tUNUMBER, 1 },
  { 0, "1st",   tUNUMBER, 1 },
/*  { 0, "second",    tUNUMBER, 2 }, */
  { 0, "2nd",   tUNUMBER, 2 },
  { 0, "third",   tUNUMBER, 3 },
  { 0, "3rd",   tUNUMBER, 3 },
  { 0, "fourth",    tUNUMBER, 4 },
  { 0, "4th",   tUNUMBER, 4 },
  { 0, "fifth",   tUNUMBER, 5 },
  { 0, "5th",   tUNUMBER, 5 },
  { 0, "sixth",   tUNUMBER, 6 },
  { 0, "seventh",   tUNUMBER, 7 },
  { 0, "eighth",    tUNUMBER, 8 },
  { 0, "ninth",   tUNUMBER, 9 },
  { 0, "tenth",   tUNUMBER, 10 },
  { 0, "eleventh",  tUNUMBER, 11 },
  { 0, "twelfth",   tUNUMBER, 12 },
  { 0, "ago",   tAGO,   1 },

  /* Military timezones. */
  { 0, "a", tZONE,  1*HOUR },
  { 0, "b", tZONE,  2*HOUR },
  { 0, "c", tZONE,  3*HOUR },
  { 0, "d", tZONE,  4*HOUR },
  { 0, "e", tZONE,  5*HOUR },
  { 0, "f", tZONE,  6*HOUR },
  { 0, "g", tZONE,  7*HOUR },
  { 0, "h", tZONE,  8*HOUR },
  { 0, "i", tZONE,  9*HOUR },
  { 0, "k", tZONE,  10*HOUR },
  { 0, "l", tZONE,  11*HOUR },
  { 0, "m", tZONE,  12*HOUR },
  { 0, "n", tZONE,  -1*HOUR },
  { 0, "o", tZONE,  -2*HOUR },
  { 0, "p", tZONE,  -3*HOUR },
  { 0, "q", tZONE,  -4*HOUR },
  { 0, "r", tZONE,  -5*HOUR },
  { 0, "s", tZONE,  -6*HOUR },
  { 0, "t", tZONE,  -7*HOUR },
  { 0, "u", tZONE,  -8*HOUR },
  { 0, "v", tZONE,  -9*HOUR },
  { 0, "w", tZONE,  -10*HOUR },
  { 0, "x", tZONE,  -11*HOUR },
  { 0, "y", tZONE,  -12*HOUR },
  { 0, "z", tZONE,  0*HOUR },

  /* End of table. */
  { 0, NULL,  0,  0 }
};

/*
 * Year is either:
 *  = A number from 0 to 99, which means a year from 1970 to 2069, or
 *  = The actual year (>=100).
 */
static time_t
Convert(time_t Month, time_t Day, time_t Year,
  time_t Hours, time_t Minutes, time_t Seconds,
  time_t Timezone, enum DSTMODE DSTmode)
{
  signed char DaysInMonth[12] = {
    31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
  };
  time_t    Julian;
  int   i;
  struct tm *ltime;
#if defined(HAVE_LOCALTIME_R) || defined(HAVE_LOCALTIME_S)
  struct tm tmbuf;
#endif

  if (Year < 69)
    Year += 2000;
  else if (Year < 100)
    Year += 1900;
  DaysInMonth[1] = Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0)
      ? 29 : 28;
  if (Year < EPOCH || (sizeof(time_t) <= 4 && Year >= 2038)
      || Month < 1 || Month > 12
      /* Lint fluff:  "conversion from long may lose accuracy" */
      || Day < 1 || Day > DaysInMonth[(int)--Month]
      || Hours < 0 || Hours > 23
      || Minutes < 0 || Minutes > 59
      || Seconds < 0 || Seconds > 59)
    return -1;

  Julian = Day - 1;
  for (i = 0; i < Month; i++)
    Julian += DaysInMonth[i];
  for (i = EPOCH; i < Year; i++)
    Julian += 365 + (i % 4 == 0);
  Julian *= DAY;
  Julian += Timezone;
  Julian += Hours * HOUR + Minutes * MINUTE + Seconds;
#if defined(HAVE_LOCALTIME_S)
  ltime = localtime_s(&tmbuf, &Julian) ? NULL : &tmbuf;
#elif defined(HAVE_LOCALTIME_R)
  ltime = localtime_r(&Julian, &tmbuf);
#else
  ltime = localtime(&Julian);
#endif
  if (DSTmode == DSTon
      || (DSTmode == DSTmaybe && ltime->tm_isdst))
    Julian -= HOUR;
  return Julian;
}

static time_t
DSTcorrect(time_t Start, time_t Future)
{
  time_t    StartDay;
  time_t    FutureDay;
  struct tm *ltime;
#if defined(HAVE_LOCALTIME_R) || defined(HAVE_LOCALTIME_S)
  struct tm tmbuf;
#endif
#if defined(HAVE_LOCALTIME_S)
  ltime = localtime_s(&tmbuf, &Start) ? NULL : &tmbuf;
#elif defined(HAVE_LOCALTIME_R)
  ltime = localtime_r(&Start, &tmbuf);
#else
  ltime = localtime(&Start);
#endif
  StartDay = (ltime->tm_hour + 1) % 24;
#if defined(HAVE_LOCALTIME_S)
  ltime = localtime_s(&tmbuf, &Future) ? NULL : &tmbuf;
#elif defined(HAVE_LOCALTIME_R)
  ltime = localtime_r(&Future, &tmbuf);
#else
  ltime = localtime(&Future);
#endif
  FutureDay = (ltime->tm_hour + 1) % 24;
  return (Future - Start) + (StartDay - FutureDay) * HOUR;
}


static time_t
RelativeDate(time_t Start, time_t zone, int dstmode,
    time_t DayOrdinal, time_t DayNumber)
{
  struct tm *tm;
  time_t  t, now;
#if defined(HAVE_GMTIME_R) || defined(HAVE_GMTIME_S)
  struct tm tmbuf;
#endif

  t = Start - zone;
#if defined(HAVE_GMTIME_S)
  tm = gmtime_s(&tmbuf, &t) ? NULL : &tmbuf;
#elif defined(HAVE_GMTIME_R)
  tm = gmtime_r(&t, &tmbuf);
#else
  tm = gmtime(&t);
#endif
  now = Start;
  now += DAY * ((DayNumber - tm->tm_wday + 7) % 7);
  now += 7 * DAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
  if (dstmode == DSTmaybe)
    return DSTcorrect(Start, now);
  return now - Start;
}


static time_t
RelativeMonth(time_t Start, time_t Timezone, time_t RelMonth)
{
  struct tm *tm;
  time_t  Month;
  time_t  Year;
#if defined(HAVE_LOCALTIME_R) || defined(HAVE_LOCALTIME_S)
  struct tm tmbuf;
#endif

  if (RelMonth == 0)
    return 0;
#if defined(HAVE_LOCALTIME_S)
  tm = localtime_s(&tmbuf, &Start) ? NULL : &tmbuf;
#elif defined(HAVE_LOCALTIME_R)
  tm = localtime_r(&Start, &tmbuf);
#else
  tm = localtime(&Start);
#endif
  Month = 12 * (tm->tm_year + 1900) + tm->tm_mon + RelMonth;
  Year = Month / 12;
  Month = Month % 12 + 1;
  return DSTcorrect(Start,
      Convert(Month, (time_t)tm->tm_mday, Year,
    (time_t)tm->tm_hour, (time_t)tm->tm_min, (time_t)tm->tm_sec,
    Timezone, DSTmaybe));
}

/*
 * Parses and consumes an unsigned number.
 * Returns 1 if any number is parsed. Otherwise, *value is unchanged.
 */
static char
consume_unsigned_number(const char **in, time_t *value)
{
  char c;
  if (isdigit((unsigned char)(c = **in))) {
    for (*value = 0; isdigit((unsigned char)(c = *(*in)++)); )
      *value = 10 * *value + c - '0';
    (*in)--;
    return 1;
  }
  return 0;
}

/*
 * Tokenizer.
 */
static int
nexttoken(const char **in, time_t *value)
{
  char  c;
  char  buff[64];

  for ( ; ; ) {
    while (isspace((unsigned char)**in))
      ++*in;

    /* Skip parenthesized comments. */
    if (**in == '(') {
      int Count = 0;
      do {
        c = *(*in)++;
        if (c == '\0')
          return c;
        if (c == '(')
          Count++;
        else if (c == ')')
          Count--;
      } while (Count > 0);
      continue;
    }

    /* Try the next token in the word table first. */
    /* This allows us to match "2nd", for example. */
    {
      const char *src = *in;
      const struct LEXICON *tp;
      unsigned i = 0;

      /* Force to lowercase and strip '.' characters. */
      while (*src != '\0'
          && (isalnum((unsigned char)*src) || *src == '.')
          && i < sizeof(buff)-1) {
        if (*src != '.') {
          if (isupper((unsigned char)*src))
            buff[i++] = (char)tolower(
                (unsigned char)*src);
          else
            buff[i++] = *src;
        }
        src++;
      }
      buff[i] = '\0';

      /*
       * Find the first match.  If the word can be
       * abbreviated, make sure we match at least
       * the minimum abbreviation.
       */
      for (tp = TimeWords; tp->name; tp++) {
        size_t abbrev = tp->abbrev;
        if (abbrev == 0)
          abbrev = strlen(tp->name);
        if (strlen(buff) >= abbrev
            && strncmp(tp->name, buff, strlen(buff))
              == 0) {
          /* Skip over token. */
          *in = src;
          /* Return the match. */
          *value = tp->value;
          return tp->type;
        }
      }
    }

    /*
     * Not in the word table, maybe it's a number.  Note:
     * Because '-' and '+' have other special meanings, I
     * don't deal with signed numbers here.
     */
    if (consume_unsigned_number(in, value)) {
      return (tUNUMBER);
    }

    return *(*in)++;
  }
}

#define TM_YEAR_ORIGIN 1900

/* Yield A - B, measured in seconds.  */
static long
difftm (struct tm *a, struct tm *b)
{
  int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
  int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
  long days = (
    /* difference in day of year */
    a->tm_yday - b->tm_yday
    /* + intervening leap days */
    +  ((ay >> 2) - (by >> 2))
    -  (ay/100 - by/100)
    +  ((ay/100 >> 2) - (by/100 >> 2))
    /* + difference in years * 365 */
    +  (long)(ay-by) * 365
    );
  return (days * DAY + (a->tm_hour - b->tm_hour) * HOUR
      + (a->tm_min - b->tm_min) * MINUTE
      + (a->tm_sec - b->tm_sec));
}

/*
 * Parses a Unix epoch timestamp (seconds).
 * This supports a subset of what GNU tar accepts from black box testing,
 * but covers common use cases.
 */
static time_t
parse_unix_epoch(const char *p)
{
  time_t epoch;

  /* may begin with + */
  if (*p == '+') {
    p++;
  }

  /* followed by some number */
  if (!consume_unsigned_number(&p, &epoch))
    return (time_t)-1;

  /* ...and nothing else */
  if (*p != '\0')
    return (time_t)-1;

  return epoch;
}

/*
 *
 * The public function.
 *
 * TODO: tokens[] array should be dynamically sized.
 */
time_t
archive_parse_date(time_t now, const char *p)
{
  struct token  tokens[256];
  struct gdstate  _gds;
  struct token  *lasttoken;
  struct gdstate  *gds;
  struct tm local, *tm;
  struct tm gmt, *gmt_ptr;
  time_t    Start;
  time_t    tod;
  long    tzone;

  /*
   * @-prefixed Unix epoch timestamps (seconds)
   * Skip the complex tokenizer - We do not want to accept strings like "@tenth"
   */
  if (*p == '@')
    return parse_unix_epoch(p + 1);

  /* Clear out the parsed token array. */
  memset(tokens, 0, sizeof(tokens));
  /* Initialize the parser state. */
  memset(&_gds, 0, sizeof(_gds));
  gds = &_gds;

  /* Look up the current time. */
#if defined(HAVE_LOCALTIME_S)
  tm = localtime_s(&local, &now) ? NULL : &local;
#elif defined(HAVE_LOCALTIME_R)
  tm = localtime_r(&now, &local);
#else
  memset(&local, 0, sizeof(local));
  tm = localtime(&now);
#endif
  if (tm == NULL)
    return -1;
#if !defined(HAVE_LOCALTIME_R) && !defined(HAVE_LOCALTIME_S)
  local = *tm;
#endif

  /* Look up UTC if we can and use that to determine the current
   * timezone offset. */
#if defined(HAVE_GMTIME_S)
  gmt_ptr = gmtime_s(&gmt, &now) ? NULL : &gmt;
#elif defined(HAVE_GMTIME_R)
  gmt_ptr = gmtime_r(&now, &gmt);
#else
  memset(&gmt, 0, sizeof(gmt));
  gmt_ptr = gmtime(&now);
  if (gmt_ptr != NULL) {
    /* Copy, in case localtime and gmtime use the same buffer. */
    gmt = *gmt_ptr;
  }
#endif
  if (gmt_ptr != NULL)
    tzone = difftm (&gmt, &local);
  else
    /* This system doesn't understand timezones; fake it. */
    tzone = 0;
  if(local.tm_isdst)
    tzone += HOUR;

  /* Tokenize the input string. */
  lasttoken = tokens;
  while ((lasttoken->token = nexttoken(&p, &lasttoken->value)) != 0) {
    ++lasttoken;
    if (lasttoken > tokens + 255)
      return -1;
  }
  gds->tokenp = tokens;

  /* Match phrases until we run out of input tokens. */
  while (gds->tokenp < lasttoken) {
    if (!phrase(gds))
      return -1;
  }

  /* Use current local timezone if none was specified. */
  if (!gds->HaveZone) {
    gds->Timezone = tzone;
    gds->DSTmode = DSTmaybe;
  }

  /* If a timezone was specified, use that for generating the default
   * time components instead of the local timezone. */
  if (gds->HaveZone && gmt_ptr != NULL) {
    now -= gds->Timezone;
#if defined(HAVE_GMTIME_S)
    gmt_ptr = gmtime_s(&gmt, &now) ? NULL : &gmt;
#elif defined(HAVE_GMTIME_R)
    gmt_ptr = gmtime_r(&now, &gmt);
#else
    gmt_ptr = gmtime(&now);
#endif
    if (gmt_ptr != NULL)
      local = *gmt_ptr;
    now += gds->Timezone;
  }

  if (!gds->HaveYear)
    gds->Year = local.tm_year + 1900;
  if (!gds->HaveMonth)
    gds->Month = local.tm_mon + 1;
  if (!gds->HaveDay)
    gds->Day = local.tm_mday;
  /* Note: No default for hour/min/sec; a specifier that just
   * gives date always refers to 00:00 on that date. */

  /* If we saw more than one time, timezone, weekday, year, month,
   * or day, then give up. */
  if (gds->HaveTime > 1 || gds->HaveZone > 1 || gds->HaveWeekDay > 1
      || gds->HaveYear > 1 || gds->HaveMonth > 1 || gds->HaveDay > 1)
    return -1;

  /* Compute an absolute time based on whatever absolute information
   * we collected. */
  if (gds->HaveYear || gds->HaveMonth || gds->HaveDay
      || gds->HaveTime || gds->HaveWeekDay) {
    Start = Convert(gds->Month, gds->Day, gds->Year,
        gds->Hour, gds->Minutes, gds->Seconds,
        gds->Timezone, gds->DSTmode);
    if (Start < 0)
      return -1;
  } else {
    Start = now;
    if (!gds->HaveRel)
      Start -= local.tm_hour * HOUR + local.tm_min * MINUTE
          + local.tm_sec;
  }

  /* Add the relative offset. */
  Start += gds->RelSeconds;
  Start += RelativeMonth(Start, gds->Timezone, gds->RelMonth);

  /* Adjust for day-of-week offsets. */
  if (gds->HaveWeekDay
      && !(gds->HaveYear || gds->HaveMonth || gds->HaveDay)) {
    tod = RelativeDate(Start, gds->Timezone,
        gds->DSTmode, gds->DayOrdinal, gds->DayNumber);
    Start += tod;
  }

  /* -1 is an error indicator, so return 0 instead of -1 if
   * that's the actual time. */
  return Start == -1 ? 0 : Start;
}


#if defined(TEST)

/* ARGSUSED */
int
main(int argc, char **argv)
{
    time_t  d;
    time_t  now = time(NULL);

    while (*++argv != NULL) {
      (void)printf("Input: %s\n", *argv);
      d = get_date(now, *argv);
      if (d == -1)
        (void)printf("Bad format - couldn't convert.\n");
      else
        (void)printf("Output: %s\n", ctime(&d));
    }
    exit(0);
    /* NOTREACHED */
}
#endif  /* defined(TEST) */

Coverage Report

Created: 2026-03-12 06:35