/**
 *  @file  recursivedescent.cc
 *  @brief  Implementation of a recursive descent IMAP command parser.
 *  @author Andreas Aardal Hanssen
 *  @date 2002-2005
 */

#include "recursivedescent.h"

#include "convert.h"
#include "imapparser.h"
#include "iodevice.h"
#include "iofactory.h"
#include "session.h"

#include <iomanip>
#include <iostream>
#include <stack>

#include <ctype.h>
#include <stdio.h>

using namespace Binc;
using std::string;

std::stack<int> Binc::inputBuffer;
int Binc::charnr = 0;

Operator::ParseResult Binc::expectThisString(const string &s_in)
{
  Session &session = Session::getInstance();

  string tmp;

  bool match = true;
  for (string::const_iterator i = s_in.begin(); i != s_in.end(); ++i) {
    char c;
    if (!bincClient.readChar(&c)) {
      session.setLastError(bincClient.getLastErrorString());

      if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
      return Operator::ERROR;
    }

    tmp += c;

    if (toupper(*i) != toupper(c)) {
      match = false;
      break;
    }
  }

  if (!match) {
    bincClient.unreadStr(tmp);
    return Operator::REJECT;
  } else {
    return Operator::ACCEPT;
  }
}

Operator::ParseResult Binc::expectDateTime(string &s_in)
{
  Session &session = Session::getInstance();

  if (expectThisString("\"") != Operator::ACCEPT) return Operator::REJECT;

  unsigned int digit1, digit2;
  if (expectSPACE() == Operator::ACCEPT) {
    digit1 = 0;
    Operator::ParseResult res;
    if ((res = expectDigit(digit2)) != Operator::ACCEPT) {
      session.setLastError("expected digit (day) after \" and a SPACE.");
      return res;
    }
  } else {
    Operator::ParseResult res;
    if ((res = expectDigit(digit1)) != Operator::ACCEPT) {
      session.setLastError("expected first digit of day");
      return res;
    }
    if ((res = expectDigit(digit2)) != Operator::ACCEPT) {
      session.setLastError("expected second digit of day");
      return res;
    }
  }

  int day = digit1 * 10 + digit2;

  BincStream daystr;

  if (day < 10) daystr << '0';
  daystr << day;

  s_in += daystr.str();

  Operator::ParseResult res;
  if ((res = expectThisString("-")) != Operator::ACCEPT) {
    session.setLastError("expected -");
    return res;
  }

  s_in += "-";

  /* month */
  if ((res = expectThisString("Jan")) == Operator::ACCEPT) {
    s_in += "Jan";
  } else if ((res = expectThisString("Feb")) == Operator::ACCEPT) {
    s_in += "Feb";
  } else if ((res = expectThisString("Mar")) == Operator::ACCEPT) {
    s_in += "Mar";
  } else if ((res = expectThisString("Apr")) == Operator::ACCEPT) {
    s_in += "Apr";
  } else if ((res = expectThisString("May")) == Operator::ACCEPT) {
    s_in += "May";
  } else if ((res = expectThisString("Jun")) == Operator::ACCEPT) {
    s_in += "Jun";
  } else if ((res = expectThisString("Jul")) == Operator::ACCEPT) {
    s_in += "Jul";
  } else if ((res = expectThisString("Aug")) == Operator::ACCEPT) {
    s_in += "Aug";
  } else if ((res = expectThisString("Sep")) == Operator::ACCEPT) {
    s_in += "Sep";
  } else if ((res = expectThisString("Oct")) == Operator::ACCEPT) {
    s_in += "Oct";
  } else if ((res = expectThisString("Nov")) == Operator::ACCEPT) {
    s_in += "Nov";
  } else if ((res = expectThisString("Dec")) == Operator::ACCEPT) {
    s_in += "Dec";
  } else {
    session.setLastError("expected month");
    return res;
  }

  if ((res = expectThisString("-")) != Operator::ACCEPT) {
    session.setLastError("expected -");
    return res;
  }

  s_in += "-";

  /* year */
  unsigned int year, c;
  if ((res = expectDigit(year)) != Operator::ACCEPT) {
    session.setLastError("expected digit (first digit of year)");
    return res;
  }

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit (second digit of year)");
    return res;
  }

  year = (year * 10) + c;

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit (third digit of year)");
    return res;
  }

  year = (year * 10) + c;

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit (last digit of year)");
    return res;
  }

  year = (year * 10) + c;

  BincStream yearstr;

  yearstr << year;

  s_in += yearstr.str();

  if ((res = expectSPACE()) != Operator::ACCEPT) {
    session.setLastError("expected SPACE");
    return res;
  }

  s_in += " ";

  if ((res = expectTime(s_in)) != Operator::ACCEPT) {
    session.setLastError("expected time");
    return res;
  }

  if ((res = expectSPACE()) != Operator::ACCEPT) {
    session.setLastError("expected SPACE");
    return res;
  }

  s_in += " ";

  if ((res = expectZone(s_in)) != Operator::ACCEPT) {
    session.setLastError("expected zone");
    return res;
  }

  if ((res = expectThisString("\"")) != Operator::ACCEPT) {
    session.setLastError("expected \"");
    return res;
  }

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectTime(string &s_in)
{
  Session &session = Session::getInstance();

  unsigned int c, t;
  Operator::ParseResult res;
  if ((res = expectDigit(t)) != Operator::ACCEPT) return res;

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  t = (t * 10) + c;

  BincStream tstr;

  tstr << t;

  s_in += tstr.str();

  if ((res = expectThisString(":")) != Operator::ACCEPT) {
    session.setLastError("expected colon");
    return res;
  }

  s_in += ":";

  if ((res = expectDigit(t)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  t = (t * 10) + c;

  tstr.clear();

  tstr << t;

  s_in += tstr.str();

  if ((res = expectThisString(":")) != Operator::ACCEPT) {
    session.setLastError("expected colon");
    return res;
  }

  s_in += ":";

  if ((res = expectDigit(t)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  t = (t * 10) + c;

  tstr.clear();

  tstr << t;

  s_in += tstr.str();

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectZone(string &s_in)
{
  Session &session = Session::getInstance();

  Operator::ParseResult res;
  if ((res = expectThisString("-")) == Operator::ACCEPT)
    s_in += "-";
  else if ((res = expectThisString("+")) == Operator::ACCEPT)
    s_in += "+";
  else
    return res;

  unsigned int c, t;
  if ((res = expectDigit(t)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  t = (t * 10) + c;

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  t = (t * 10) + c;

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  t = (t * 10) + c;

  BincStream tstr;

  tstr << t;

  s_in += tstr.str();

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectListWildcards(int &c_in)
{
  Operator::ParseResult res;
  if ((res = expectThisString("%")) == Operator::ACCEPT) {
    c_in = '%';
    return Operator::ACCEPT;
  } else if ((res = expectThisString("*")) == Operator::ACCEPT) {
    c_in = '*';
    return Operator::ACCEPT;
  } else {
    return res;
  }
}

Operator::ParseResult Binc::expectListMailbox(string &s_in)
{
  Operator::ParseResult res;
  if ((res = expectString(s_in)) == Operator::ACCEPT) return Operator::ACCEPT;

  int c;
  if ((res = expectAtomChar(c)) == Operator::ACCEPT
      || (res = expectListWildcards(c)) == Operator::ACCEPT
      || (res = expectThisString("]")) == Operator::ACCEPT)
  {
    do {
      s_in += (char)c;
      if ((res = expectAtomChar(c)) != Operator::ACCEPT
          && (res = expectListWildcards(c)) != Operator::ACCEPT
          && (res = expectThisString("]")) != Operator::ACCEPT)
      {
        return Operator::ACCEPT;
      }
    } while (1);
  }

  bincClient.unreadStr(s_in);

  return res;
}

Operator::ParseResult Binc::expectFlag(std::vector<string> &v_in)
{
  Session &session = Session::getInstance();

  Operator::ParseResult res;
  string flag;
  if ((res = expectThisString("\\Answered")) == Operator::ACCEPT) {
    v_in.push_back("\\Answered");
  } else if ((res = expectThisString("\\Flagged")) == Operator::ACCEPT) {
    v_in.push_back("\\Flagged");
  } else if ((res = expectThisString("\\Deleted")) == Operator::ACCEPT) {
    v_in.push_back("\\Deleted");
  } else if ((res = expectThisString("\\Seen")) == Operator::ACCEPT) {
    v_in.push_back("\\Seen");
  } else if ((res = expectThisString("\\Draft")) == Operator::ACCEPT) {
    v_in.push_back("\\Draft");
  } else if ((res = expectThisString("\\Answered")) == Operator::ACCEPT) {
    v_in.push_back("\\Answered");
  } else if ((res = expectThisString("\\")) == Operator::ACCEPT) {
    if ((res = expectAtom(flag)) == Operator::ACCEPT) {
      v_in.push_back("\\" + flag);
    } else {
      session.setLastError("expected atom");
      return res;
    }

  } else if (expectAtom(flag) == Operator::ACCEPT) {
    v_in.push_back(flag);
  } else {
    return res;
  }

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectDate(string &s_in)
{
  Session &session = Session::getInstance();

  Operator::ParseResult res;
  bool quoted = false;
  if ((res = expectThisString("\"")) == Operator::ACCEPT) quoted = true;

  /* day */
  unsigned int day, c;
  if ((res = expectDigit(c)) == Operator::ACCEPT) {
    day = c;
    if ((res = expectDigit(c)) == Operator::ACCEPT) day = (day * 10) + c;

    BincStream daystr;

    daystr << day;

    s_in += daystr.str();
  } else {
    session.setLastError("expected digit");
    return res;
  }

  /* - */
  if ((res = expectThisString("-")) != Operator::ACCEPT) {
    session.setLastError("expected -");
    return res;
  }

  s_in += '-';

  /* month */
  if ((res = expectThisString("Jan")) == Operator::ACCEPT) {
    s_in += "Jan";
  } else if ((res = expectThisString("Feb")) == Operator::ACCEPT) {
    s_in += "Feb";
  } else if ((res = expectThisString("Mar")) == Operator::ACCEPT) {
    s_in += "Mar";
  } else if ((res = expectThisString("Apr")) == Operator::ACCEPT) {
    s_in += "Apr";
  } else if ((res = expectThisString("May")) == Operator::ACCEPT) {
    s_in += "May";
  } else if ((res = expectThisString("Jun")) == Operator::ACCEPT) {
    s_in += "Jun";
  } else if ((res = expectThisString("Jul")) == Operator::ACCEPT) {
    s_in += "Jul";
  } else if ((res = expectThisString("Aug")) == Operator::ACCEPT) {
    s_in += "Aug";
  } else if ((res = expectThisString("Sep")) == Operator::ACCEPT) {
    s_in += "Sep";
  } else if ((res = expectThisString("Oct")) == Operator::ACCEPT) {
    s_in += "Oct";
  } else if ((res = expectThisString("Nov")) == Operator::ACCEPT) {
    s_in += "Nov";
  } else if ((res = expectThisString("Dec")) == Operator::ACCEPT) {
    s_in += "Dec";
  } else {
    session.setLastError("expected month");
    return res;
  }

  /* - */
  if ((res = expectThisString("-")) != Operator::ACCEPT) {
    session.setLastError("expected -");
    return res;
  }

  s_in += '-';

  /* year */
  unsigned int year;
  if ((res = expectDigit(year)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  year = (year * 10) + c;

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  year = (year * 10) + c;

  if ((res = expectDigit(c)) != Operator::ACCEPT) {
    session.setLastError("expected digit");
    return res;
  }

  year = (year * 10) + c;

  BincStream yearstr;

  yearstr << year;

  s_in += yearstr.str();

  if (quoted) {
    if ((res = expectThisString("\"")) != Operator::ACCEPT) {
      session.setLastError("expected \"");
      return res;
    }
  }

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectCRLF()
{
  Operator::ParseResult res;
  if ((res = expectCR()) == Operator::ACCEPT && (res = expectLF()) == Operator::ACCEPT)
    return Operator::ACCEPT;
  else
    return res;
}

Operator::ParseResult Binc::expectCR()
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  if (c == 0x0d) {
    return Operator::ACCEPT;
  } else {
    bincClient.unreadChar(c);
    return Operator::REJECT;
  }
}

Operator::ParseResult Binc::expectLF()
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  if (c == 0x0a) {
    return Operator::ACCEPT;
  } else {
    bincClient.unreadChar(c);
    return Operator::REJECT;
  }
}

Operator::ParseResult Binc::expectTagChar(int &c_in)
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  switch (c) {
  case 041:
  case 043:
  case 044:
  case 046:
  case 047:
  case 054:
  case 055:
  case 056:
  case 057:
  case 060:
  case 061:
  case 062:
  case 063:
  case 064:
  case 065:
  case 066:
  case 067:
  case 070:
  case 071:
  case 072:
  case 073:
  case 074:
  case 075:
  case 076:
  case 077:
  case 0100:
  case 0101:
  case 0102:
  case 0103:
  case 0104:
  case 0105:
  case 0106:
  case 0107:
  case 0110:
  case 0111:
  case 0112:
  case 0113:
  case 0114:
  case 0115:
  case 0116:
  case 0117:
  case 0120:
  case 0121:
  case 0122:
  case 0123:
  case 0124:
  case 0125:
  case 0126:
  case 0127:
  case 0130:
  case 0131:
  case 0132:
  case 0133:
  case 0135:
  case 0136:
  case 0137:
  case 0140:
  case 0141:
  case 0142:
  case 0143:
  case 0144:
  case 0145:
  case 0146:
  case 0147:
  case 0150:
  case 0151:
  case 0152:
  case 0153:
  case 0154:
  case 0155:
  case 0156:
  case 0157:
  case 0160:
  case 0161:
  case 0162:
  case 0163:
  case 0164:
  case 0165:
  case 0166:
  case 0167:
  case 0170:
  case 0171:
  case 0172:
  case 0174:
  case 0175:
  case 0176:
    c_in = c;
    return Operator::ACCEPT;
  default:
    break;
  }

  bincClient.unreadChar(c);

  return Operator::REJECT;
}

Operator::ParseResult Binc::expectTag(string &s_in)
{
  string tag;
  int tagchar;

  int eres = expectTagChar(tagchar);
  if (eres == Operator::REJECT) {
    return Operator::REJECT;
  } else if (eres == Operator::ERROR) {
    return Operator::ERROR;
  } else if (eres == Operator::TIMEOUT) {
    return Operator::TIMEOUT;
  } else {
    tag += tagchar;

    bool done = false;

    while (!done) {
      switch (expectTagChar(tagchar)) {
      case Operator::ACCEPT:
        tag += tagchar;
        break;
      case Operator::REJECT:
        done = true;
        break;
      case Operator::ERROR:
        return Operator::ERROR;
      case Operator::TIMEOUT:
        return Operator::TIMEOUT;
      }
    }
  }

  s_in = tag;

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectSPACE()
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  if (c == ' ') {
    return Operator::ACCEPT;
  } else {
    bincClient.unreadChar(c);
    return Operator::REJECT;
  }
}

Operator::ParseResult Binc::expectMailbox(string &s_in)
{
  return expectAstring(s_in);
}

// FIXME: This rule is wrong.
Operator::ParseResult Binc::expectAstring(string &s_in)
{
  Operator::ParseResult res;
  if ((res = expectAtom(s_in)) == Operator::ACCEPT) return Operator::ACCEPT;

  if ((res = expectString(s_in)) == Operator::ACCEPT) return Operator::ACCEPT;

  return res;
}

Operator::ParseResult Binc::expectAtomChar(int &c_in)
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  switch (c) {
  case 041:
  case 043:
  case 044:
  case 046:
  case 047:
  case 053:
  case 054:
  case 055:
  case 056:
  case 057:
  case 060:
  case 061:
  case 062:
  case 063:
  case 064:
  case 065:
  case 066:
  case 067:
  case 070:
  case 071:
  case 072:
  case 073:
  case 074:
  case 075:
  case 076:
  case 077:
  case 0100:
  case 0101:
  case 0102:
  case 0103:
  case 0104:
  case 0105:
  case 0106:
  case 0107:
  case 0110:
  case 0111:
  case 0112:
  case 0113:
  case 0114:
  case 0115:
  case 0116:
  case 0117:
  case 0120:
  case 0121:
  case 0122:
  case 0123:
  case 0124:
  case 0125:
  case 0126:
  case 0127:
  case 0130:
  case 0131:
  case 0132:
  case 0133:
  case 0135:
  case 0136:
  case 0137:
  case 0140:
  case 0141:
  case 0142:
  case 0143:
  case 0144:
  case 0145:
  case 0146:
  case 0147:
  case 0150:
  case 0151:
  case 0152:
  case 0153:
  case 0154:
  case 0155:
  case 0156:
  case 0157:
  case 0160:
  case 0161:
  case 0162:
  case 0163:
  case 0164:
  case 0165:
  case 0166:
  case 0167:
  case 0170:
  case 0171:
  case 0172:
  case 0174:
  case 0175:
  case 0176:
    c_in = c;
    return Operator::ACCEPT;
  default:
    break;
  }

  bincClient.unreadChar(c);
  return Operator::REJECT;
}

Operator::ParseResult Binc::expectAtom(string &s_in)
{
  string atom;
  int atomchar;

  Operator::ParseResult res;
  while ((res = expectAtomChar(atomchar)) == Operator::ACCEPT)
    atom += atomchar;

  if (atom == "") {
    bincClient.unreadStr(atom);
    return res;
  } else {
    s_in = atom;
  }

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectString(string &s_in)
{
  Operator::ParseResult res;
  if ((res = expectQuoted(s_in)) == Operator::ACCEPT) return Operator::ACCEPT;

  if ((res = expectLiteral(s_in)) == Operator::ACCEPT) return Operator::ACCEPT;

  return res;
}

Operator::ParseResult Binc::expectQuoted(string &s_in)
{
  string quoted;
  int quotedchar;
  Operator::ParseResult res;

  if ((res = expectThisString("\"")) != Operator::ACCEPT) return res;

  while ((res = expectQuotedChar(quotedchar)) == Operator::ACCEPT)
    quoted += quotedchar;

  if ((res = expectThisString("\"")) != Operator::ACCEPT) {
    bincClient.unreadStr("\"" + quoted);
    return res;
  }

  s_in = quoted;
  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectQuotedChar(int &c_in)
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  switch (c) {
  case 01:
  case 02:
  case 03:
  case 04:
  case 05:
  case 06:
  case 07:
  case 010:
  case 011:
  case 013:
  case 014:
  case 016:
  case 017:
  case 020:
  case 021:
  case 022:
  case 023:
  case 024:
  case 025:
  case 026:
  case 027:
  case 030:
  case 031:
  case 032:
  case 033:
  case 034:
  case 035:
  case 036:
  case 037:
  case 040:
  case 041:
  case 043:
  case 044:
  case 045:
  case 046:
  case 047:
  case 050:
  case 051:
  case 052:
  case 053:
  case 054:
  case 055:
  case 056:
  case 057:
  case 060:
  case 061:
  case 062:
  case 063:
  case 064:
  case 065:
  case 066:
  case 067:
  case 070:
  case 071:
  case 072:
  case 073:
  case 074:
  case 075:
  case 076:
  case 077:
  case 0100:
  case 0101:
  case 0102:
  case 0103:
  case 0104:
  case 0105:
  case 0106:
  case 0107:
  case 0110:
  case 0111:
  case 0112:
  case 0113:
  case 0114:
  case 0115:
  case 0116:
  case 0117:
  case 0120:
  case 0121:
  case 0122:
  case 0123:
  case 0124:
  case 0125:
  case 0126:
  case 0127:
  case 0130:
  case 0131:
  case 0132:
  case 0133:
  case 0135:
  case 0136:
  case 0137:
  case 0140:
  case 0141:
  case 0142:
  case 0143:
  case 0144:
  case 0145:
  case 0146:
  case 0147:
  case 0150:
  case 0151:
  case 0152:
  case 0153:
  case 0154:
  case 0155:
  case 0156:
  case 0157:
  case 0160:
  case 0161:
  case 0162:
  case 0163:
  case 0164:
  case 0165:
  case 0166:
  case 0167:
  case 0170:
  case 0171:
  case 0172:
  case 0173:
  case 0174:
  case 0175:
  case 0176:
  case 0177:
    c_in = c;
    return Operator::ACCEPT;
  case '\\': {
    char d;
    if (!bincClient.readChar(&d)) {
      session.setLastError(bincClient.getLastErrorString());

      if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
      return Operator::ERROR;
    }

    if (d == '\"' || d == '\\') {
      c_in = d;
      return Operator::ACCEPT;
    } else {
      bincClient.unreadChar(d);
      bincClient.unreadChar(c);
      return Operator::REJECT;
    }
  }
  default:
    break;
  }

  bincClient.unreadChar(c);
  return Operator::REJECT;
}

Operator::ParseResult Binc::expectLiteral(string &s_in)
{
  Session &session = Session::getInstance();

  string literal;
  Operator::ParseResult res;

  if ((res = expectThisString("{")) != Operator::ACCEPT) return res;

  unsigned int nchar;

  if ((res = expectNumber(nchar)) != Operator::ACCEPT) {
    session.setLastError("expected number");
    return res;
  }

  // rfc2088 describes the non-synchronizing literal, or LITERAL+, as
  // sent by the client with an extra '+' appended after the octet
  // count.
  bool literalPlus = false;
  if ((res = expectThisString("+")) == Operator::ACCEPT) literalPlus = true;

  if ((res = expectThisString("}")) != Operator::ACCEPT) {
    session.setLastError("expected }");
    return res;
  }

  if ((res = expectCRLF()) != Operator::ACCEPT) {
    session.setLastError("expected CRLF");
    return Operator::ERROR;
  }

  // Only send the reply if the client did not send a LITERAL+
  // request.
  if (!literalPlus) {
    bincClient << "+ ok, send " << nchar << " bytes of data." << std::endl;
    bincClient.flush();
  }

  for (unsigned int i = 0; i < nchar; ++i) {
    char c;
    if (!bincClient.readChar(&c)) {
      session.setLastError(bincClient.getLastErrorString());
      if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
      return Operator::ERROR;
    }

    literal += c;
  }

  s_in = literal;

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectNumber(unsigned int &i_in)
{
  i_in = 0;
  unsigned int n;
  Operator::ParseResult res;

  while ((res = expectDigit(n)) == Operator::ACCEPT)
    if (i_in == 0)
      i_in = n;
    else
      i_in = (i_in * 10) + n;

  if (res == Operator::TIMEOUT) return res;

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectDigit(unsigned int &i_in)
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  if (c == '0') {
    i_in = 0;
    return Operator::ACCEPT;
  } else {
    bincClient.unreadChar(c);
  }

  if (expectDigitNZ(i_in) != Operator::ACCEPT) return Operator::REJECT;

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectDigitNZ(unsigned int &i_in)
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  switch (c) {
  case '1':
    i_in = 1;
    break;
  case '2':
    i_in = 2;
    break;
  case '3':
    i_in = 3;
    break;
  case '4':
    i_in = 4;
    break;
  case '5':
    i_in = 5;
    break;
  case '6':
    i_in = 6;
    break;
  case '7':
    i_in = 7;
    break;
  case '8':
    i_in = 8;
    break;
  case '9':
    i_in = 9;
    break;
  case -1:
    session.setLastError(bincClient.getLastErrorString());
    return Operator::ERROR;
  case -2:
    return Operator::TIMEOUT;
  default:
    bincClient.unreadChar(c);
    return Operator::REJECT;
  }

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectSet(SequenceSet &s_in)
{
  Session &session = Session::getInstance();
  unsigned int seqnum = (unsigned int)-1;

  Operator::ParseResult res;

  /* if a set does not start with a sequencenum, then it's not a
   * set. :-) seqnum == -1 means '*'. */
  if ((res = expectSequenceNum(seqnum)) != Operator::ACCEPT) return res;

  /* the first number is always a part of the set */
  s_in.addNumber(seqnum);

  /* if _after_ a set there is a ':', then there will always be a
   * sequencenum after the colon. if not, it's a syntax error. a
   * colon delimits two numbers in a range. */
  if ((res = expectThisString(":")) == Operator::ACCEPT) {
    unsigned int seqnum2 = (unsigned int)-1;
    if ((res = expectSequenceNum(seqnum2)) != Operator::ACCEPT) {
      session.setLastError("expected sequencenum");
      return res;
    }

    s_in.addRange(seqnum, seqnum2);
  }

  /* if _after_ a set there is a ',', then there will always be
   * a set after the comma. if not, it's a syntax error. */
  if ((res = expectThisString(",")) == Operator::ACCEPT) {
    if ((res = expectSet(s_in)) != Operator::ACCEPT) {
      session.setLastError("expected set");
      return res;
    }
  }

  return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectSequenceNum(unsigned int &i_in)
{
  Session &session = Session::getInstance();

  char c;
  if (!bincClient.readChar(&c)) {
    session.setLastError(bincClient.getLastErrorString());

    if (bincClient.getLastError() == IODevice::Timeout) return Operator::TIMEOUT;
    return Operator::ERROR;
  }

  if (c == '*') {
    i_in = (unsigned int)-1;
    return Operator::ACCEPT;
  } else {
    bincClient.unreadChar(c);
  }

  if (expectNZNumber(i_in) != Operator::ACCEPT)
    return Operator::REJECT;
  else
    return Operator::ACCEPT;
}

Operator::ParseResult Binc::expectNZNumber(unsigned int &i_in)
{
  unsigned int c;
  Operator::ParseResult res;

  if ((res = expectDigitNZ(c)) != Operator::ACCEPT) return res;

  i_in = c;
  while ((res = expectDigit(c)) == Operator::ACCEPT)
    i_in = (i_in * 10) + c;

  if (res == Operator::TIMEOUT) return res;

  return Operator::ACCEPT;
}