# FBB::String(3bobcat)

## Operations on std::string objects
(libbobcat-dev_6.06.02)

## 2005-2024

## NAME

FBB::String - Several operations on std::string objects

## SYNOPSIS

#include <bobcat/string>
Linking option: -lbobcat

## DESCRIPTION

This class offers facilities for often used transformations on std::string objects, which are not supported by the std::string class itself. All members of FBB::String are static.

Initially this class was derived from std::string. Deriving from std::string, however, is considerd bad design as std::string was not designed as a base-class.

FBB::String offers a series of static member functions providing the facilities originally implemented as non-static members. One of these members is the (overloaded) split member, splitting a string into elements separated by one or more configurable characters. These elements may contain or consist of double- or single-quoted (sub) strings and escape characters. Escape characters are converted to their implied byte-values (e.g., \n is converted to byte value 10) unless they are embedded in single-quoted (sub) strings. Quotes surrounding double- and single-quoted (sub) strings are removed from the elements returned by the split members.

## NAMESPACE

FBB
All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace FBB.

## INHERITS FROM

--

## ENUMERATIONS

- Type:
  This enumeration indicates the nature of the content of an element in the array returned by the overloaded split members (see below).

  DQUOTE, a subset of the characters in the matching string element was delimited by double quotes in the in the string that was parsed by the split members.

  DQUOTE_UNTERMINATED, the content of the string that was parsed by the split members started at some point with a double quote, but the matching ending double quote was lacking.

  ESCAPED_END, the content of the string that was parsed by the split members ended in a mere backslash.

  NORMAL, a normal string;

  SEPARATOR, a separator;

  SQUOTE, a subset of the characters in the matching string element was delimited by quotes in the in the string that was parsed by the split members.

  SQUOTE_UNTERMINATED, the content of the string that was parsed by the split members started at some point with a quote, but the matching ending quote was lacking.

- SplitType:
  This enumeration is used to specify how split members should split the information in the string objects that are passed to these members:

  TOK: the split member acts like the standard C function strtok(3). The essence here is that no empty elements are returned. E.g., a string containing "a,," which is processed using the TOK mode returns a NORMAL element containing "a".

  TOKSEP: the split member acts like the standard C function strtok(3), also returning information about encountered separators. Since strtok doesn't return empty elements, TOKSEP uses empty elements to indicate the occurrence of separators. E.g., a string containing "a,," which is processed using the TOKSEP mode returns a NORMAL element containing "a", followed by two empty SEPARATOR elements.

  STR: the split member acts like the standard C function strstr(3). The essence here is that empty elements are also returned. E.g., a string containing "a,," which is processed using the STR mode returns an element containing "a", followed by two empty NORMAL elements.

  STRSEP: the split member acts like the standard C function strstr(3), also returning information about encountered separators. E.g., a string containing "a,," which is processed using the STRSEP mode returns a NORMAL element containing "a", followed by a SEPARATOR element containing ",", followed by a NORMAL empty element, followed by a SEPARATOR element containing ",", and finally followed by a NORMAL empty element,

## NESTED TYPE

The struct SplitPair defines a std::pair<std::string, String::Type> and is used by some overloaded split members (see below).

## STATIC MEMBER FUNCTIONS

- char const **argv(std::vector<std::string> const &words):
  Returns a pointer to an allocated series of pointers to the C strings stored in the vector words. The caller is responsible for returning the array of pointers to the common pool, but should not delete the C-strings to which the pointers point. The last element of the returned array is guaranteed to be a 0-pointer.

- int casecmp(std::string const &lhs, std::string const &rhs):
  Performs a case-insensitive comparison of the content of two std::string objects. A negative value is returned if lhs should be ordered before rhs; 0 is returned if the two strings have identical content; a positive value is returned if the lhs object should be ordered beyond rhs.

- std::string escape(std::string const &str, char const *series = "'\"\\"):
  Returns a copy of str in which all characters in series are prefixed by a backslash character.

- std::string join(std::vector<std::string> const &words, char sep):
  The elements of the words vector are returned as one string, separated from each other by the sep character;

- std::string join(std::vector<SplitPair> const &entries, char sep, bool all = true):
  The first fields of the elements in entries are returned as one string, separated from each other by the sep character. If the parameter all is specified as false then elements whose second fields are equal to String::SEPARATOR are ignored.

- std::string lc(std::string const &str) const:
  Returns a copy of str in which all letters were transformed to lower case letters.

- std::vector<String::SplitPair> split(std::string const &str, SplitType mode, char const *sep = " \t"):
  The string str is split into substrings, separated by any of the characters in sep. The substrings are returned in a vector of SplitPair elements, using the specified SplitType mode (cf. the description of the various SplitPair values and their effects in the ENUMERATIONS section).

- std::vector<String::SplitPair> split(std::string const &str, char const *separators = " \t", bool addEmpty = false):
  This member acts like the previous one, using addEmpty == false to select mode TOK and addEmpty == true to select mode TOKSEP.

- size_t split(std::vector<String::SplitPair> *entries, std::string const &str, SplitType mode, char const *sep = " \t"):
  Same functionality as the first split member, but this member stores the SplitPair elements in the vector pointed at by the entries parameter, first clearing the vector. This member returns the new value of entries->size().

- size_t split(std::vector<String::SplitPair> *entries, std::string const &str, char const *sep = " \t", bool addEmpty = false):
  This member acts like the previous one, using addEmpty == false to select mode TOK and addEmpty == true to select mode TOKSEP.

- std::vector<std::string> split(Type *type, std::string const &str, SplitType stype, char const *sep = " \t"):
  Same functionality as the first split member, but this member merely stores the first fields of the SplitPair elements in the returned vector. The String::Type variable whose address is passed to the type parameter is set to NORMAL if the final entry was successfully determined; to DQUOTE_UNTERMINATED if a final closing double quote could not be found; to SQUOTE_UNTERMINATED if a final closing single quote could not be found; and to ESCAPE_END if the final character in str is a backslash character.

- std::vector<std::string> split(Type *type, std::string const &str, char const *sep = " \t", bool addEmpty = false):
  This member acts like the previous one, using addEmpty == false to select mode TOK and addEmpty == true to select mode TOKSEP.

- size_t split(std::vector<std::string> *words, std::string const &str, SplitType stype, char const *sep = " \t"):
  Same functionality as the first split member, but this member merely stores the first fields of the encountered SplitPair elements in the vector pointed at by words, first clearing the vector. This member returns the new value of words->size().

- size_t split(std::vector<std::string> *words, std::string const &str, char const *sep = " \t", bool addEmpty = false):
  This member acts like the previous one, using addEmpty == false to select mode TOK and addEmpty == true to select mode TOKSEP.

- std::string trim(std::string const &str):
  Returns a copy of str from which leading and trailing blank characters were removed.

- std::string uc(std::string const &str):
  Returns a copy of str in which all letters were capitalized.

- std::string unescape(std::string const &str):
  Returns a copy of str in which the escaped (i.e., prefixed by a backslash) characters were interpreted. All standard escape characters (\a, \b, \f, \n, \r, \t, \v) are recognized. If an escape character is followed by x at most the next two characters are interpreted as a hexadecimal number. If an escape character is followed by an octal digit, then at most the next three characters following the backslash are interpreted as an octal number. In all other cases, the backslash is removed and the character following the backslash is kept.

- std::string urlDecode(std::string const &str):
  URL specifications use %xx encoding to encode characters, except for alpha-numeric characters and the characters - _ . and ~, which are kept as-is. Other characters are encode by a % character, followed by two hexadecimal characters representing those characters' byte value. E.g., a blank space is encoded as %20, a plus character is encoded as %2B. The member urlDecode returns a std::string containing the decoded characters of the url-encoded string that is passed as argument to this member.

- std::string urlEncode(std::string const &str):
  See the member urlDecode: urlEncode returns a std::string containing the url-encoded characters of the characters in the string that is passed as argument to this member.

## EXAMPLE

    #include <iostream>
    #include <vector>
    #include <bobcat/string>

    using namespace std;
    using namespace FBB;

    static char const *type[] =
    {
        "DQUOTE_UNTERMINATED",
        "SQUOTE_UNTERMINATED",
        "ESCAPED_END",
        "SEPARATOR",
        "NORMAL",
        "DQUOTE",
        "SQUOTE",
    };

    int main(int argc, char **argv)
    {
        cout << "Program's name in uppercase: " << String::uc(argv[0]) << "\n\n";

        vector<String::SplitPair> splitpair;
        string text{ "one, two, 'thr\\x65\\145'" };
        string encoded{ String::urlEncode(text) };

        cout << "The string `" << text << "'\n"
                "   as url-encoded string: `" << encoded << "'\n"
                "   and the latter string url-decoded: " <<
                                        String::urlDecode(encoded) << "\n"
                "\n"
                "Splitting `" << text << "' into " <<
                        String::split(&splitpair, text, String::STRSEP, ", ") <<
                    " fields\n";

        for (auto it = splitpair.begin(); it != splitpair.end(); ++it)
            cout << (it - splitpair.begin() + 1) << ": " <<
                    type[it->second] << ": `" << it->first <<
                    "', unescaped: `" << String::unescape(it->first) <<
                    "'\n";

        cout << '\n' <<
            text << ":\n"
            "   upper case: " << String::uc(text) << ",\n"
            "   lower case: " << String::lc(text) << '\n';
    }

    /*
        Calling the program as
            driver'
        results in the following output:
            Program's name in uppercase: DRIVER

            Splitting `one, two, 'thr\x65\145'' into 9 fields
            1: NORMAL: `one', unescaped: `one'
            2: SEPARATOR: `,', unescaped: `,'
            3: NORMAL: `', unescaped: `'
            4: SEPARATOR: ` ', unescaped: ` '
            5: NORMAL: `two', unescaped: `two'
            6: SEPARATOR: `,', unescaped: `,'
            7: NORMAL: `', unescaped: `'
            8: SEPARATOR: ` ', unescaped: ` '
            9: SQUOTE: `thr\x65\145', unescaped: `three'

            one, two, 'thr\x65\145':
               upper case: ONE, TWO, 'THR\X65\145',
               lower case: one, two, 'thr\x65\145'

    */

## FILES

bobcat/string - defines the class interface

## SEE ALSO

bobcat(7)

## BUGS

None Reported.

## BOBCAT PROJECT FILES

- https://fbb-git.gitlab.io/bobcat/: gitlab project page;
- bobcat_6.06.02-x.dsc: detached signature;
- bobcat_6.06.02-x.tar.gz: source archive;
- bobcat_6.06.02-x_i386.changes: change log;
- libbobcat1_6.06.02-x_*.deb: debian package containing the libraries;
- libbobcat1-dev_6.06.02-x_*.deb: debian package containing the libraries, headers and manual pages;

## BOBCAT

Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.

## COPYRIGHT

This is free software, distributed under the terms of the GNU General Public License (GPL).

## AUTHOR

Frank B. Brokken (f.b.brokken@rug.nl).