FBB::String - Several operations on std::string objects
#include <bobcat/string>
Linking option: -lbobcat
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.
FBB
All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace FBB.
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- 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.
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- 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,
The typedef SplitPair represents
std::pair<std::string, String::Type> and is used by some
overloaded split members (see below).
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- 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.
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- 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.
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- 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.
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- 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;
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- 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.
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- std::string lc(std::string const &str) const:
Returns a copy of str in which all letters were transformed to lower
case letters.
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- 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).
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- 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.
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- 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().
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- 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.
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- 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.
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- 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.
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- 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().
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- 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.
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- std::string trim(std::string const &str):
Returns a copy of str from which leading and trailing blank
characters were removed.
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- std::string uc(std::string const &str):
Returns a copy of str in which all letters were capitalized.
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- 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.
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- 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.
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- 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.
#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’
*/
bobcat/string - defines the class interface
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- https://fbb-git.gitlab.io/bobcat/: gitlab project page;
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- bobcat_5.07.00-x.dsc: detached signature;
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- bobcat_5.07.00-x.tar.gz: source archive;
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- bobcat_5.07.00-x_i386.changes: change log;
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- libbobcat1_5.07.00-x_*.deb: debian package containing the
libraries;
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- libbobcat1-dev_5.07.00-x_*.deb: debian package containing the
libraries, headers and manual pages;
Bobcat is an acronym of `Brokken’s Own Base Classes And
Templates’.
This is free software, distributed under the terms of the GNU
General Public License (GPL).
Frank B. Brokken (f.b.brokken@rug.nl).