[libi2ncommon] / src / stringfunc.cpp

/** @file
 *
 * (c) Copyright 2007-2008 by Intra2net AG
 *
 * info@intra2net.com
 */

#include <iostream>
#include <string>
#include <sstream>
#include <stdexcept>

#include <wchar.h>
#include <stdlib.h>
#include <iconv.h>
#include <i18n.h>

#include <stringfunc.hxx>

using namespace std;

namespace I2n
{


namespace
{

const std::string hexDigitsLower("0123456789abcdef");
const std::string hexDigitsUpper("0123456789ABCDEF");


struct UpperFunc
{
   char operator() (char c)
   {
      return std::toupper(c);
   }
}; // eo struct UpperFunc


struct LowerFunc
{
   char operator() (char c)
   {
      return std::tolower(c);
   }
}; // eo struct LowerFunc


} // eo namespace <anonymous>


/**
 * default list of Whitespaces (" \t\r\n");
 */
const std::string Whitespaces = " \t\r\n";

/**
 * default list of lineendings ("\r\n");
 */
const std::string LineEndings= "\r\n";


/**
 * @brief checks if a string begins with a given prefix.
 * @param[in,out] str the string which is tested
 * @param prefix the prefix which should be tested for.
 * @return @a true iff the prefix is not empty and the string begins with that prefix.
 */
bool has_prefix(const std::string& str, const std::string& prefix)
{
   if (prefix.empty() || str.empty() || str.size() < prefix.size() )
   {
      return false;
   }
   return str.compare(0, prefix.size(), prefix) == 0;
} // eo has_prefix(const std::string&,const std::string&)


/**
 * @brief checks if a string ends with a given suffix.
 * @param[in,out] str the string which is tested
 * @param suffix the suffix which should be tested for.
 * @return @a true iff the suffix is not empty and the string ends with that suffix.
 */
bool has_suffix(const std::string& str, const std::string& suffix)
{
   if (suffix.empty() || str.empty() || str.size() < suffix.size() )
   {
      return false;
   }
   return str.compare(str.size() - suffix.size(), suffix.size(), suffix) == 0;
} // eo has_suffix(const std::string&,const std::string&)


/**
 * cut off characters from a given list from front and end of a string.
 * @param[in,out] str the string which should be trimmed.
 * @param charlist the list of characters to remove from beginning and end of string
 * @return the result string.
 */
std::string trim_mod(std::string& str, const std::string& charlist)
{
   // first: trim the beginning:
   std::string::size_type pos= str.find_first_not_of (charlist);
   if (pos == std::string::npos)
   {
      // whole string consists of charlist (or is already empty)
      str.clear();
      return str;
   }
   else if (pos>0)
   {
      // str starts with charlist
      str.erase(0,pos);
   }
   // now let's look at the tail:
   pos= str.find_last_not_of(charlist) +1;  // note: we already know there is at least one other char!
   if ( pos < str.size() )
   {
      str.erase(pos, str.size()-pos);
   }
   return str;
} // eo trim_mod(std::string&,const std::string&)


/**
 * removes last character from a string when it is in a list of chars to be removed.
 * @param[in,out] str the string.
 * @param what the list of chars which will be tested for.
 * @return the resulting string with last char removed (if applicable)
 */
std::string chomp_mod(std::string& str, const std::string& what)
{
   if (str.empty() || what.empty() )
   {
      return str;
   }
   if (what.find(str.at (str.size()-1) ) != std::string::npos)
   {
      str.erase(str.size() - 1);
   }
   return str;
} // eo chomp_mod(std::string&,const std::string&)


/**
 * @brief converts a string to lower case.
 * @param[in,out] str the string to modify.
 * @return the string
 */
std::string to_lower_mod(std::string& str)
{
   std::transform(str.begin(), str.end(), str.begin(), LowerFunc() );
   return str;
} // eo to_lower_mod(std::string&)


/**
 * @brief converts a string to upper case.
 * @param[in,out] str the string to modify.
 * @return the string
 */
std::string to_upper_mod(std::string& str)
{
   std::transform( str.begin(), str.end(), str.begin(), UpperFunc() );
   return str;
} // eo to_upper_mod(std::string&)


/**
 * cut off characters from a given list from front and end of a string.
 * @param str the string which should be trimmed.
 * @param charlist the list of characters to remove from beginning and end of string
 * @return the result string.
 */
std::string trim (const std::string& str, const std::string& charlist)
{
   // first: trim the beginning:
   std::string::size_type pos0= str.find_first_not_of(charlist);
   if (pos0 == std::string::npos)
   {
      // whole string consists of charlist (or is already empty)
      return std::string();
   }
   // now let's look at the end:
   std::string::size_type pos1= str.find_last_not_of(charlist);
   return str.substr(pos0, pos1 - pos0 + 1);
} // eo trim(const std:.string&,const std::string&)


/**
 * removes last character from a string when it is in a list of chars to be removed.
 * @param str the string.
 * @param what the list of chars which will be tested for.
 * @return the resulting string with last char removed (if applicable)
 */
std::string chomp (const std::string& str, const std::string& what)
{
   if (str.empty() || what.empty() )
   {
      return str;
   }
   if (what.find(str.at (str.size()-1) ) != std::string::npos)
   {
      return str.substr(0, str.size()-1);
   }
   return str;
} // eo chomp(const std:.string&,const std::string&)


/**
 * @brief returns a lower case version of a given string.
 * @param str the string
 * @return the lower case version of the string
 */
std::string to_lower (const std::string& str)
{
   std::string result(str);
   return to_lower_mod(result);
} // eo to_lower(const std::string&)


/**
 * @brief returns a upper case version of a given string.
 * @param str the string
 * @return the upper case version of the string
 */
std::string to_upper(const std::string& str)
{
   std::string result(str);
   return to_upper_mod(result);
} // eo to_upper(const std::string&)


/**
 * @brief removes a given suffix from a string.
 * @param str the string.
 * @param suffix the suffix which should be removed if the string ends with it.
 * @return the string without the suffix.
 *
 * If the string ends with the suffix, it is removed. If the the string doesn't end
 * with the suffix the original string is returned.
 */
std::string remove_suffix(const std::string& str, const std::string& suffix)
{
   if (has_suffix(str,suffix) )
   {
      return str.substr(0, str.size()-suffix.size() );
   }
   return str;
} // eo remove_suffix(const std::string&,const std::string&)


/**
 * @brief removes a given prefix from a string.
 * @param str the string.
 * @param prefix the prefix which should be removed if the string begins with it.
 * @return the string without the prefix.
 *
 * If the string begins with the prefix, it is removed. If the the string doesn't begin
 * with the prefix the original string is returned.
 */
std::string remove_prefix(const std::string& str, const std::string& prefix)
{
   if (has_prefix(str,prefix) )
   {
      return str.substr( prefix.size() );
   }
   return str;
} // eo remove_prefix(const std::string&,const std::string&)


/**
 * split a string to key and value delimited by a given delimiter.
 * The resulting key and value strings are trimmed (Whitespaces removed at beginning and end).
 * @param str the string which should be splitted.
 * @param[out] key the resulting key
 * @param[out] value the resulting value
 * @param delimiter the delimiter between key and value; default is '='.
 * @return @a true if the split was successful.
 */
bool pair_split(
   const std::string& str,
   std::string& key,
   std::string& value,
   char delimiter)
{
   std::string::size_type pos = str.find (delimiter);
   if (pos == std::string::npos) return false;
   key= str.substr(0,pos);
   value= str.substr(pos+1);
   trim_mod(key);
   trim_mod(value);
   return true;
} // eo pair_split(const std::string&,std::string&,std::string&,char)


/**
 * splits a string by given delimiter
 *
 * @param[in] str the string which should be splitted.
 * @param[out] result the list resulting from splitting  @a str.
 * @param[in] delimiter the delimiter (word/phrase) at which @a str should be splitted.
 * @param[in] omit_empty should empty parts not be stored?
 * @param[in] trim_list list of characters the parts should be trimmed by.
 *  (empty string results in no trim)
 */
void split_string(
   const std::string& str,
   std::list<std::string>& result,
   const std::string& delimiter,
   bool omit_empty,
   const std::string& trim_list
)
{
   std::string::size_type pos, last_pos=0;
   bool delimiter_found= false;
   while ( last_pos < str.size()  && last_pos != std::string::npos)
   {
      pos= str.find(delimiter, last_pos);
      std::string part;
      if (pos == std::string::npos)
      {
         part= str.substr(last_pos);
         delimiter_found= false;
      }
      else
      {
         part= str.substr(last_pos, pos-last_pos);
         delimiter_found=true;
      }
      if (pos != std::string::npos)
      {
         last_pos= pos+ delimiter.size();
      }
      else
      {
         last_pos= std::string::npos;
      }
      if (!trim_list.empty() ) trim_mod (part, trim_list);
      if (omit_empty && part.empty() ) continue;
      result.push_back( part );
   }
   // if the string ends with a delimiter we need to append an empty string if no omit_empty
   // was given.
   // (this way we keep the split result consistent to a join operation)
   if (delimiter_found && !omit_empty)
   {
      result.push_back("");
   }
} // eo split_string(const std::string&,std::list< std::string >&,const std::string&,bool,const std::string&)


/**
 * splits a string by a given delimiter
 * @param str the string which should be splitted.
 * @param delimiter delimiter the delimiter (word/phrase) at which @a str should be splitted.
 * @param[in] omit_empty should empty parts not be stored?
 * @param[in] trim_list list of characters the parts should be trimmed by.
 *  (empty string results in no trim)
 * @return the list resulting from splitting @a str.
 */
std::list<std::string> split_string(
   const std::string& str,
   const std::string& delimiter,
   bool omit_empty,
   const std::string& trim_list
)
{
   std::list<std::string> result;
   split_string(str, result, delimiter, omit_empty, trim_list);
   return result;
} // eo split_string(const std::string&,const std::string&,bool,const std::string&)


/**
 * @brief joins a list of strings into a single string.
 *
 * This funtion is (basically) the reverse operation of @a split_string.
 *
 * @param parts the list of strings.
 * @param delimiter the delimiter which is inserted between the strings.
 * @return the joined string.
 */
std::string join_string(
   const std::list< std::string >& parts,
   const std::string& delimiter
)
{
   std::string result;
   if (! parts.empty() )
   {
      std::list< std::string >::const_iterator it= parts.begin();
      result = *it;
      while ( ++it != parts.end() )
      {
         result+= delimiter;
         result+= *it;
      }
   }
   return result;
} // eo join_string(const std::list< std::string >&,const std::string&)


/*
** conversions
*/


/**
 * @brief returns a hex string from a binary string.
 * @param str the (binary) string
 * @param upper_case_digits determine whether to use upper case characters for digits A-F.
 * @return the string in hex notation.
 */
std::string convert_binary_to_hex(
   const std::string& str,
   bool upper_case_digits
)
{
   std::string result;
   std::string hexDigits(upper_case_digits ? hexDigitsUpper : hexDigitsLower);
   for ( std::string::const_iterator it= str.begin();
         it != str.end();
         ++it)
   {
      result.push_back( hexDigits[ ( (*it) >> 4) & 0x0f ] );
      result.push_back( hexDigits[ (*it) & 0x0f ] );
   }
   return result;
} // eo convert_binary_to_hex(const std::string&,bool)


/**
 * @brief converts a hex digit string to binary string.
 * @param str hex digit string
 * @return the binary string.
 *
 * The hex digit string may contains white spaces or colons which are treated
 * as delimiters between hex digit groups.
 *
 * @todo rework the handling of half nibbles (consistency)!
 */
std::string convert_hex_to_binary(
   const std::string& str
)
throw (std::runtime_error)
{
   std::string result;
   char c= 0;
   bool hasNibble= false;
   bool lastWasWS= true;
   for ( std::string::const_iterator it= str.begin();
         it != str.end();
         ++it)
   {
      std::string::size_type p = hexDigitsLower.find( *it );
      if (p== std::string::npos)
      {
         p= hexDigitsUpper.find( *it );
      }
      if (p == std::string::npos)
      {
         if (   ( Whitespaces.find( *it ) != std::string::npos) // is it a whitespace?
                or ( *it == ':') // or a colon?
            )
         {
            // we treat that as a valid delimiter:
            if (hasNibble)
            {
               // 1 nibble before WS is treate as lower part:
               result.push_back(c);
               // reset state:
               hasNibble= false;
            }
            lastWasWS= true;
            continue;
         }
      }
      if (p == std::string::npos )
      {
         throw runtime_error("illegal character in hex digit string: " + str);
      }
      lastWasWS= false;
      if (hasNibble)
      {
         c<<=4;
      }
      else
      {
         c=0;
      }
      c+= (p & 0x0f);
      if (hasNibble)
      {
         //we already had a nibble, so a char is complete now:
         result.push_back( c );
         hasNibble=false;
      }
      else
      {
         // this is the first nibble of a new char:
         hasNibble=true;
      }
   }
   if (hasNibble)
   {
      //well, there is one nibble left
      // let's do some heuristics:
      if (lastWasWS)
      {
         // if the preceeding character was a white space (or a colon)
         // we treat the nibble as lower part:
         //( this is consistent with shortened hex notations where leading zeros are not noted)
         result.push_back( c );
      }
      else
      {
         // if it was part of a hex digit chain, we treat it as UPPER part (!!)
         result.push_back( c << 4 );
      }
   }
   return result;
} // eo convert_hex_to_binary(const std::string&)


} // eo namespace I2n


std::string iso_to_utf8(const std::string& isostring)
{
   string result;

   iconv_t i2utf8 = iconv_open("UTF-8", "ISO-8859-1");

   if (iso_to_utf8 == (iconv_t)-1)
      throw runtime_error("iconv can't convert from ISO-8859-1 to UTF-8");

   size_t in_size=isostring.size();
   size_t out_size=in_size*4;

   char *buf = (char *)malloc(out_size+1);
   if (buf == NULL)
      throw runtime_error("out of memory for iconv buffer");

   const char *in = isostring.c_str();
   char *out = buf;
   iconv(i2utf8, &in, &in_size, &out, &out_size);

   buf[isostring.size()*4-out_size]=0;

   result=buf;

   free(buf);
   iconv_close(i2utf8);

   return result;
}

std::string utf8_to_iso(const std::string& utf8string)
{
   string result;

   iconv_t utf82iso = iconv_open("ISO-8859-1","UTF-8");

   if (utf82iso == (iconv_t)-1)
      throw runtime_error("iconv can't convert from UTF-8 to ISO-8859-1");

   size_t in_size=utf8string.size();
   size_t out_size=in_size;

   char *buf = (char *)malloc(out_size+1);
   if (buf == NULL)
      throw runtime_error("out of memory for iconv buffer");

   const char *in = utf8string.c_str();
   char *out = buf;
   iconv(utf82iso, &in, &in_size, &out, &out_size);

   buf[utf8string.size()-out_size]=0;

   result=buf;

   free(buf);
   iconv_close(utf82iso);

   return result;
}

wchar_t* utf8_to_wbuf(const std::string& utf8string)
{
   iconv_t utf82wstr = iconv_open("UCS-4LE","UTF-8");

   if (utf82wstr == (iconv_t)-1)
      throw runtime_error("iconv can't convert from UTF-8 to UCS-4");

   size_t in_size=utf8string.size();
   size_t out_size= (in_size+1)*sizeof(wchar_t);

   wchar_t *buf = (wchar_t *)malloc(out_size);
   if (buf == NULL)
      throw runtime_error("out of memory for iconv buffer");

   const char *in = utf8string.c_str();
   char *out = (char*) buf;
   if (iconv(utf82wstr, &in, &in_size, &out, &out_size) == -1)
      throw runtime_error("error converting char encodings");

   buf[ ( (utf8string.size()+1)*sizeof(wchar_t)-out_size) /sizeof(wchar_t) ]=0;

   iconv_close(utf82wstr);

   return buf;
}

std::string utf7imap_to_utf8(const std::string& utf7imapstring)
{
   string result;

   iconv_t utf7imap2utf8 = iconv_open("UTF-8","UTF-7-IMAP");

   if (utf7imap2utf8 == (iconv_t)-1)
      throw runtime_error("iconv can't convert from UTF-7-IMAP to UTF-8");

   size_t in_size=utf7imapstring.size();
   size_t out_size=in_size*4;

   char *buf = (char *)malloc(out_size+1);
   if (buf == NULL)
      throw runtime_error("out of memory for iconv buffer");

   const char *in = utf7imapstring.c_str();
   char *out = buf;
   iconv(utf7imap2utf8, &in, &in_size, &out, &out_size);

   buf[utf7imapstring.size()*4-out_size]=0;

   result=buf;

   free(buf);
   iconv_close(utf7imap2utf8);

   return result;
}

std::string utf8_to_utf7imap(const std::string& utf8string)
{
   string result;

   iconv_t utf82utf7imap = iconv_open("UTF-7-IMAP", "UTF-8");

   if (utf82utf7imap == (iconv_t)-1)
      throw runtime_error("iconv can't convert from UTF-7-IMAP to UTF-8");

   // UTF-7 is base64 encoded, a buffer 10x as large
   // as the utf-8 buffer should be enough. If not the string will be truncated.
   size_t in_size=utf8string.size();
   size_t out_size=in_size*10;

   char *buf = (char *)malloc(out_size+1);
   if (buf == NULL)
      throw runtime_error("out of memory for iconv buffer");

   const char *in = utf8string.c_str();
   char *out = buf;
   iconv(utf82utf7imap, &in, &in_size, &out, &out_size);

   buf[utf8string.size()*10-out_size]= 0;

   result=buf;

   free(buf);
   iconv_close(utf82utf7imap);

   return result;
}

// Tokenize string by (html) tags
void tokenize_by_tag(vector<pair<string,bool> > &tokenized, const std::string &input)
{
   string::size_type pos, len = input.size();
   bool inside_tag = false;
   string current;

   for (pos = 0; pos < len; pos++)
   {
      if (input[pos] == '<')
      {
         inside_tag = true;

         if (!current.empty() )
         {
            tokenized.push_back( make_pair(current, false) );
            current = "";
         }

         current += input[pos];
      }
      else if (input[pos] == '>' && inside_tag)
      {
         current += input[pos];
         inside_tag = false;
         if (!current.empty() )
         {
            tokenized.push_back( make_pair(current, true) );
            current = "";
         }
      }
      else
         current += input[pos];
   }

   // String left over in buffer?
   if (!current.empty() )
      tokenized.push_back( make_pair(current, false) );
} // eo tokenize_by_tag


std::string strip_html_tags(const std::string &input)
{
   // Pair first: string, second: isTag
   vector<pair<string,bool> > tokenized;
   tokenize_by_tag (tokenized, input);

   string output;
   vector<pair<string,bool> >::const_iterator token, tokens_end = tokenized.end();
   for (token = tokenized.begin(); token != tokens_end; token++)
      if (!token->second)
         output += token->first;

   return output;
} // eo strip_html_tags


// Smart-encode HTML en
string smart_html_entities(const std::string &input)
{
   // Pair first: string, second: isTag
   vector<pair<string,bool> > tokenized;
   tokenize_by_tag (tokenized, input);

   string output;
   vector<pair<string,bool> >::const_iterator token, tokens_end = tokenized.end();
   for (token = tokenized.begin(); token != tokens_end; token++)
   {
      // keep HTML tags as they are
      if (token->second)
         output += token->first;
      else
         output += html_entities(token->first);
   }

   return output;
}


string::size_type find_8bit(const std::string &str)
{
   string::size_type l=str.size();
   for (string::size_type p=0; p < l; p++)
      if (static_cast<unsigned char>(str[p]) > 127)
         return p;

   return string::npos;
}

// encoded UTF-8 chars into HTML entities
string html_entities(std::string str)
{
   // Normal chars
   replace_all (str, "&", "&amp;");
   replace_all (str, "\"", "&quot;");
   replace_all (str, "<", "&lt;");
   replace_all (str, ">", "&gt;");

   // Umlauts
   replace_all (str, "\xC3\xA4", "&auml;");
   replace_all (str, "\xC3\xB6", "&ouml;");
   replace_all (str, "\xC3\xBC", "&uuml;");
   replace_all (str, "\xC3\x84", "&Auml;");
   replace_all (str, "\xC3\x96", "&Ouml;");
   replace_all (str, "\xC3\x9C", "&Uuml;");

   // Misc
   replace_all (str, "\xC3\x9F", "&szlig;");

   // conversion of remaining non-ASCII chars needed?
   // just do if needed because of performance
   if (find_8bit(str) != string::npos)
   {
      // convert to fixed-size encoding UTF-32
      wchar_t* wbuf=utf8_to_wbuf(str);
      ostringstream target;

      // replace all non-ASCII chars with HTML representation
      for (int p=0; wbuf[p] != 0; p++)
      {
         unsigned int c=wbuf[p];

         if (c <= 127)
            target << static_cast<unsigned char>(c);
         else
            target << "&#" << c << ';';
      }

      free(wbuf);

      str=target.str();
   }

   return str;
} // eo html_entities(std::string)


bool replace_all(string &base, const char *ist, const char *soll)
{
   string i=ist;
   string s=soll;
   return replace_all(base,&i,&s);
}

bool replace_all(string &base, const string &ist, const char *soll)
{
   string s=soll;
   return replace_all(base,&ist,&s);
}

bool replace_all(string &base, const string *ist, const string *soll)
{
   return replace_all(base,*ist,*soll);
}

bool replace_all(string &base, const char *ist, const string *soll)
{
   string i=ist;
   return replace_all(base,&i,soll);
}

bool replace_all(string &base, const string &ist, const string &soll)
{
   bool found_ist = false;
   string::size_type a=0;

   if (ist.empty() )
      throw runtime_error ("replace_all called with empty search string");

   while ( (a=base.find(ist,a) ) != string::npos)
   {
      base.replace(a,ist.size(),soll);
      a=a+soll.size();
      found_ist = true;
   }

   return found_ist;
}

string to_lower(const string &src)
{
   string dst = src;

   string::size_type pos, end = dst.size();
   for (pos = 0; pos < end; pos++)
      dst[pos] = tolower(dst[pos]);

   return dst;
}

string to_upper(const string &src)
{
   string dst = src;

   string::size_type pos, end = dst.size();
   for (pos = 0; pos < end; pos++)
      dst[pos] = toupper(dst[pos]);

   return dst;
}

string nice_unit_format(int input)
{
   float size = input;
   int sizecount = 0;

   while (size > 1000)
   {
      size = size / 1000;
      sizecount++;
   }

   float tmp;                       // round
   tmp = size*10;
   tmp += 0.5;
   tmp = int (tmp);
   tmp = float (tmp) /float (10);
   size = tmp;

   ostringstream out;

   out.setf (ios::fixed);
   out.precision (2);
   switch (sizecount)
   {
      case 0:
         out << size << i18n (" Bytes");
         break;
      case 1:
         out << size << i18n (" KBytes");
         break;
      case 2:
         out << size << i18n (" MBytes");
         break;
      case 3:
         out << size << i18n (" GBytes");
         break;
      case 4:
         out << size << i18n (" TBytes");
         break;
      case 5:
         out << size << i18n (" PBytes");
         break;
      case 6:
         out << size << i18n (" EBytes");
         break;
      default:
         out << size << "*10^" << (sizecount*3)<< i18n (" Bytes");
         break;
   }

   return out.str();
} // eo nice_unit_format(int input)


string escape(const string &s)
{
   string out(s);
   string::size_type p;

   p=0;
   while ( (p=out.find_first_of("\"\\",p) ) !=out.npos)
   {
      out.insert (p,"\\");
      p+=2;
   }

   p=0;
   while ( (p=out.find_first_of("\r",p) ) !=out.npos)
   {
      out.replace (p,1,"\\r");
      p+=2;
   }

   p=0;
   while ( (p=out.find_first_of("\n",p) ) !=out.npos)
   {
      out.replace (p,1,"\\n");
      p+=2;
   }

   out='"'+out+'"';

   return out;
} // eo scape(const std::string&)


string descape(const string &s, int startpos, int &endpos)
{
   string out;

   if (s.at(startpos) != '"')
      throw out_of_range("value not type escaped string");

   out=s.substr(startpos+1);
   string::size_type p=0;

   // search for the end of the string
   while ( (p=out.find("\"",p) ) !=out.npos)
   {
      int e=p-1;
      bool escaped=false;

      // the " might be escaped with a backslash
      while (e>=0 && out.at (e) =='\\')
      {
         if (escaped == false)
            escaped=true;
         else
            escaped=false;

         e--;
      }

      if (escaped==false)
         break;
      else
         p++;
   }

   // we now have the end of the string
   out=out.substr(0,p);

   // tell calling prog about the endposition
   endpos=startpos+p+1;

   // descape all \ stuff inside the string now
   p=0;
   while ( (p=out.find_first_of("\\",p) ) !=out.npos)
   {
      switch (out.at(p+1) )
      {
         case 'r':
            out.replace(p,2,"\r");
            break;
         case 'n':
            out.replace(p,2,"\n");
            break;
         default:
            out.erase(p,1);
      }
      p++;
   }

   return out;
} // eo descape(const std::string&,int,int&)


string escape_shellarg(const string &input)
{
   string output = "'";
   string::const_iterator it, it_end = input.end();
   for (it = input.begin(); it != it_end; it++)
   {
      if ( (*it) == '\'')
         output += "'\\'";

      output += *it;
   }

   output += "'";
   return output;
}