/* ftpparse.c, ftpparse.h: library for parsing FTP LIST responses
   D. J. Bernstein, djb@pobox.com
   19970712 (doc updated 19970810)
   Commercial use is fine, if you let me know what programs you're using this in.

   Currently covered:
   EPLF.
   UNIX ls, with or without gid.
   Microsoft FTP Service.
   Windows NT FTP Server.
   VMS.
   WFTPD (DOS).
   NetPresenz (Mac).
   NetWare.

   Definitely not covered:
   Long VMS filenames, with information split across two lines.
   NCSA Telnet FTP server. Has LIST = NLST (and bad NLST for directories).

   Written for maximum portability, but tested only under UNIX so far.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif                          /*
                                 * HAVE_CONFIG_H
                                 */

#include <sys/types.h>
#include <time.h>
#include "ftpparse.h"

static long totai(year, month, mday)
long year;
long month;
long mday;
{
  /*
   * adapted from datetime_untai()
   */
  /*
   * about 100x faster than typical mktime()
   */
  long result;
  if (month >= 2)
    month -= 2;
  else
    {
      month += 10;
      --year;
    }
  result = (mday - 1) * 10 + 5 + 306 * month;
  result /= 10;
  if (result == 365)
    {
      year -= 3;
      result = 1460;
    }
  else
    result += 365 * (year % 4);
  year /= 4;
  result += 1461 * (year % 25);
  year /= 25;
  if (result == 36524)
    {
      year -= 3;
      result = 146096;
    }
  else
    {
      result += 36524 * (year % 4);
    }
  year /= 4;
  result += 146097 * (year - 5);
  result += 11017;
  return result * 86400;
}

static int flagneedbase = 1;
static time_t base;             /*
                                 * time() value on this OS at the beginning of 1970 TAI
                                 */
static long now;                /*
                                 * current time
                                 */
static int flagneedcurrentyear = 1;
static long currentyear;        /*
                                 * approximation to current year
                                 */

static void initbase()
{
  struct tm *t;

  if (!flagneedbase)
    return;

  base = 0;
  t = gmtime(&base);
  base =
    -(totai(t->tm_year + 1900, t->tm_mon, t->tm_mday) +
      t->tm_hour * 3600 + t->tm_min * 60 + t->tm_sec);
  /*
   * time_t is assumed to be measured in TAI seconds.
   */
  /*
   * base may be slightly off if time_t is measured in UTC seconds.
   */
  /*
   * Typical software naively claims to use UTC but actually uses TAI.
   */
  flagneedbase = 0;
}

static void initnow()
{
  long day;
  long year;

  initbase();
  now = time((time_t *)0) - base;

  if (flagneedcurrentyear)
    {
      /*
       * adapted from datetime_tai()
       */
      day = now / 86400;
      if ((now % 86400) < 0)
        --day;
      day -= 11017;
      year = 5 + day / 146097;
      day = day % 146097;
      if (day < 0)
        {
          day += 146097;
          --year;
        }
      year *= 4;
      if (day == 146096)
        {
          year += 3;
          day = 36524;
        }
      else
        {
          year += day / 36524;
          day %= 36524;
        }
      year *= 25;
      year += day / 1461;
      day %= 1461;
      year *= 4;
      if (day == 1460)
        {
          year += 3;
          day = 365;
        }
      else
        {
          year += day / 365;
          day %= 365;
        }
      day *= 10;
      if ((day + 5) / 306 >= 10)
        ++year;
      currentyear = year;
      flagneedcurrentyear = 0;
    }
}

/* UNIX ls does not show the year for dates in the last six months. */
/* So we have to guess the year. */
/* Apparently NetWare uses ``twelve months'' instead of ``six months''; ugh. */
/* Some versions of ls also fail to show the year for future dates. */
static long guesstai(month, mday)
long month;
long mday;
{
  long year;
  long t;

  initnow();

  for (year = currentyear - 1; year < currentyear + 100; ++year)
    {
      t = totai(year, month, mday);
      if (now - t < 350 * 86400)
        return t;
    }
/* Added by Grendel */
  return 0;
}

static int check(buf, monthname)
char *buf;
char *monthname;
{
  if ((buf[0] != monthname[0]) && (buf[0] != monthname[0] - 32))
    return 0;
  if ((buf[1] != monthname[1]) && (buf[1] != monthname[1] - 32))
    return 0;
  if ((buf[2] != monthname[2]) && (buf[2] != monthname[2] - 32))
    return 0;
  return 1;
}

static char *months[12] = {
  "jan", "feb", "mar", "apr", "may", "jun", "jul", "aug", "sep", "oct",
  "nov", "dec"
};

static int getmonth(buf, len)
char *buf;
int len;
{
  int i;
  if (len == 3)
    for (i = 0; i < 12; ++i)
      if (check(buf, months[i]))
        return i;
  return -1;
}

static long getlong(buf, len)
char *buf;
int len;
{
  long u = 0;
  while (len-- > 0)
    u = u * 10 + (*buf++ - '0');
  return u;
}

static long long getlonglong(buf, len)
char *buf;
int len;
{
  long long u = 0;
  while (len-- > 0)
    u = u * 10 + (*buf++ - '0');
  return u;
}

int ftpparse(fp, buf, len)
struct ftpparse *fp;
char *buf;
int len;
{
  int i;
  int j;
  int state;
  off_t size = -1;
  long year;
  long month = -1;
  long mday = -1;
  long hour;
  long minute;

  fp->name = 0;
  fp->namelen = 0;
  fp->flagtrycwd = 0;
  fp->flagtryretr = 0;
  fp->sizetype = FTPPARSE_SIZE_UNKNOWN;
  fp->size = 0;
  fp->mtimetype = FTPPARSE_MTIME_UNKNOWN;
  fp->mtime = 0;
  fp->idtype = FTPPARSE_ID_UNKNOWN;
  fp->id = 0;
  fp->idlen = 0;

  if (len < 2)                  /*
                                 * an empty name in EPLF, with no info, could be 2 chars
                                 */
    return 0;

  switch (*buf)
    {
    /*
     * see http://pobox.com/~djb/proto/eplf.txt
     */
    /*
     * "+i8388621.29609,m824255902,/,\tdev"
     */
    /*
     * "+i8388621.44468,m839956783,r,s10376,\tRFCEPLF"
     */
    case '+':
      i = 1;
      for (j = 1; j < len; ++j)
        {
          if (buf[j] == 9)
            {
              fp->name = buf + j + 1;
              fp->namelen = len - j - 1;
              return 1;
            }
          if (buf[j] == ',')
            {
              switch (buf[i])
                {
                case '/':
                  fp->flagtrycwd = 1;
                  break;

                case 'r':
                  fp->flagtryretr = 1;
                  break;

                case 's':
                  fp->sizetype = FTPPARSE_SIZE_BINARY;
                  fp->size = getlonglong(buf + i + 1, j - i - 1);
                  break;

                case 'm':
                  fp->mtimetype = FTPPARSE_MTIME_LOCAL;
                  initbase();
                  fp->mtime = base + getlong(buf + i + 1, j - i - 1);
                  break;

                case 'i':
                  fp->idtype = FTPPARSE_ID_FULL;
                  fp->id = buf + i + 1;
                  fp->idlen = j - i - 1;
                }
              i = j + 1;
            }
        }
      return 0;

    /*
     * UNIX-style listing, without inum and without blocks
     */
    /*
     * "-rw-r--r--   1 root     other        531 Jan 29 03:26 README"
     */
    /*
     * "dr-xr-xr-x   2 root     other        512 Apr  8  1994 etc"
     */
    /*
     * "dr-xr-xr-x   2 root     512 Apr  8  1994 etc"
     */
    /*
     * "lrwxrwxrwx   1 root     other          7 Jan 25 00:17 bin -> usr/bin"
     */
    /*
     * Also produced by Microsoft's FTP servers for Windows:
     */
    /*
     * "----------   1 owner    group         1803128 Jul 10 10:18 ls-lR.Z"
     */
    /*
     * "d---------   1 owner    group               0 May  9 19:45 Softlib"
     */
    /*
     * Also WFTPD for MSDOS:
     */
    /*
     * "-rwxrwxrwx   1 noone    nogroup      322 Aug 19  1996 message.ftp"
     */
    /*
     * Also NetWare:
     */
    /*
     * "d [R----F--] supervisor            512       Jan 16 18:53    login"
     */
    /*
     * "- [R----F--] rhesus             214059       Oct 20 15:27    cx.exe"
     */
    /*
     * Also NetPresenz for the Mac:
     */
    /*
     * "-------r--         326  1391972  1392298 Nov 22  1995 MegaPhone.sit"
     */
    /*
     * "drwxrwxr-x               folder        2 May 10  1996 network"
     */
    case 'b':
    case 'c':
    case 'd':
    case 'l':
    case 'p':
    case 's':
    case '-':

      if (*buf == 'd')
        fp->flagtrycwd = 1;
      if (*buf == '-')
        fp->flagtryretr = 1;
      if (*buf == 'l')
        fp->flagtrycwd = fp->flagtryretr = 1;

      state = 1;
      i = 0;
      for (j = 1; j < len; ++j)
        if ((buf[j] == ' ') && (buf[j - 1] != ' '))
          {
            switch (state)
              {
              case 1:   /*
                         * skipping perm
                         */
                state = 2;
                break;

              case 2:   /*
                         * skipping nlink
                         */
                state = 3;
                if ((j - i == 6) && (buf[i] == 'f'))            /*
                                                                 * for NetPresenz
                                                                 */
                  state = 4;
                break;

              case 3:   /*
                         * skipping uid
                         */
                state = 4;
                break;

              case 4:   /*
                         * getting tentative size
                         */
                size = getlonglong(buf + i, j - i);
                state = 5;
                break;

              case 5:   /*
                         * searching for month, otherwise getting tentative size
                         */
                month = getmonth(buf + i, j - i);
                if (month >= 0)
                  state = 6;
                else
                  size = getlonglong(buf + i, j - i);
                break;

              case 6:   /*
                         * have size and month
                         */
                mday = getlong(buf + i, j - i);
                state = 7;
                break;

              case 7:   /*
                         * have size, month, mday
                         */
                if ((j - i == 4) && (buf[i + 1] == ':'))
                  {
                    hour = getlong(buf + i, 1);
                    minute = getlong(buf + i + 2, 2);
                    fp->mtimetype = FTPPARSE_MTIME_REMOTEMINUTE;
                    initbase();
                    fp->mtime =
                      base + guesstai(month,
                                      mday) + hour * 3600 +
                      minute * 60;
                  }
                else if ((j - i == 5) && (buf[i + 2] == ':'))
                  {
                    hour = getlong(buf + i, 2);
                    minute = getlong(buf + i + 3, 2);
                    fp->mtimetype = FTPPARSE_MTIME_REMOTEMINUTE;
                    initbase();
                    fp->mtime =
                      base + guesstai(month,
                                      mday) + hour * 3600 +
                      minute * 60;
                  }
                else if (j - i >= 4)
                  {
                    year = getlong(buf + i, j - i);
                    fp->mtimetype = FTPPARSE_MTIME_REMOTEDAY;
                    initbase();
                    fp->mtime = base + totai(year, month, mday);
                  }
                else
                  return 0;
                fp->name = buf + j + 1;
                fp->namelen = len - j - 1;
                state = 8;
                break;

              case 8:   /*
                         * twiddling thumbs
                         */
                break;
              }
            i = j + 1;
            while ((i < len) && (buf[i] == ' '))
              ++i;
          }

      if (state != 8)
        return 0;

      fp->size = size;
      fp->sizetype = FTPPARSE_SIZE_ASCII;

      if (*buf == 'l')
        for (i = 0; i + 3 < fp->namelen; ++i)
          if (fp->name[i] == ' ')
            if (fp->name[i + 1] == '-')
              if (fp->name[i + 2] == '>')
                if (fp->name[i + 3] == ' ')
                  {
                    fp->namelen = i;
                    break;
                  }

      /*
       * eliminate extra NetWare spaces
       */
      if ((buf[1] == ' ') || (buf[1] == '['))
        if (fp->namelen > 3)
          if (fp->name[0] == ' ')
            if (fp->name[1] == ' ')
              if (fp->name[2] == ' ')
                {
                  fp->name += 3;
                  fp->namelen -= 3;
                }

      return 1;
    }

  /*
   * MultiNet (some spaces removed from examples)
   */
  /*
   * "00README.TXT;1      2 30-DEC-1996 17:44 [SYSTEM] (RWED,RWED,RE,RE)"
   */
  /*
   * "CORE.DIR;1          1  8-SEP-1996 16:09 [SYSTEM] (RWE,RWE,RE,RE)"
   */
  /*
   * and non-MutliNet VMS:
   */
  /*
   * "CII-MANUAL.TEX;1  213/216  29-JAN-1996 03:33:12  [ANONYMOU,ANONYMOUS]   (RWED,RWED,,)"
   */
  for (i = 0; i < len; ++i)
    if (buf[i] == ';')
      break;
  if (i < len)
    {
      fp->name = buf;
      fp->namelen = i;
      if (i > 4)
        if (buf[i - 4] == '.')
          if (buf[i - 3] == 'D')
            if (buf[i - 2] == 'I')
              if (buf[i - 1] == 'R')
                {
                  fp->namelen -= 4;
                  fp->flagtrycwd = 1;
                }
      if (!fp->flagtrycwd)
        fp->flagtryretr = 1;
      while (buf[i] != ' ')
        if (++i == len)
          return 0;
      while (buf[i] == ' ')
        if (++i == len)
          return 0;
      while (buf[i] != ' ')
        if (++i == len)
          return 0;
      while (buf[i] == ' ')
        if (++i == len)
          return 0;
      j = i;
      while (buf[j] != '-')
        if (++j == len)
          return 0;
      mday = getlong(buf + i, j - i);
      while (buf[j] == '-')
        if (++j == len)
          return 0;
      i = j;
      while (buf[j] != '-')
        if (++j == len)
          return 0;
      month = getmonth(buf + i, j - i);
      if (month < 0)
        return 0;
      while (buf[j] == '-')
        if (++j == len)
          return 0;
      i = j;
      while (buf[j] != ' ')
        if (++j == len)
          return 0;
      year = getlong(buf + i, j - i);
      while (buf[j] == ' ')
        if (++j == len)
          return 0;
      i = j;
      while (buf[j] != ':')
        if (++j == len)
          return 0;
      hour = getlong(buf + i, j - i);
      while (buf[j] == ':')
        if (++j == len)
          return 0;
      i = j;
      while ((buf[j] != ':') && (buf[j] != ' '))
        if (++j == len)
          return 0;
      minute = getlong(buf + i, j - i);

      fp->mtimetype = FTPPARSE_MTIME_REMOTEMINUTE;
      initbase();
      fp->mtime =
        base + totai(year, month, mday) + hour * 3600 + minute * 60;

      return 1;
    }

  /*
   * Some useless lines, safely ignored:
   */
  /*
   * "Total of 11 Files, 10966 Blocks." (VMS)
   */
  /*
   * "total 14786" (UNIX)
   */
  /*
   * "DISK$ANONFTP:[ANONYMOUS]" (VMS)
   */
  /*
   * "Directory DISK$PCSA:[ANONYM]" (VMS)
   */

  return 0;
}