ctype(3C++) - ctype(3C++)
Standard C++ Library Copyright 1998, Rogue Wave Software, Inc.
NAMEctype
- A facet that includes character classification facilities.
CTYPE<CHAR>
The ctype<char> man page has been concatenated to this man page because
of the difficulty of entering 'man ctype<char>' on the command line.
SYNOPSIS
#include <locale>
class ctype_base;
template <class charT> class ctype;
SPECIALIZATIONS
class ctype<char>;
DESCRIPTION
ctype<charT> is a facet that allows you to classify characters and per‐
form simple conversions. ctype<charT> also converts upper to lower and
lower to upper case, and converts between charT and char. ctype<charT>
relies on ctype_base for a set of masks that identify the various
classes of characters. These classes are:
alnum
alpha
cntrl
digit
graph
lower
print
punct
space
upper
xdigit
The masks are passed to member functions of ctype to obtain the classi‐
fications of a character or range of characters.
INTERFACE
class ctype_base {
public:
enum mask {
space, print, cntrl, upper, lower,
alpha, digit, punct, xdigit,
alnum=alpha|digit, graph
};
};
template <class charT>
class ctype : public locale::facet, public ctype_base {
public:
typedef charT char_type;
explicit ctype(size_t refs = 0);
bool is(mask, charT) const;
const charT* is(const charT*,
const charT*, mask*) const;
const charT* scan_is(mask, const charT*,
const charT*) const;
const charT* scan_not(mask, const charT*,
const charT*) const;
charT toupper(charT) const;
const charT* toupper(charT*, const charT*) const;
charT tolower(charT) const;
const charT* tolower(charT*, const charT*) const;
charT widen(char) const;
const char* widen(const char*,
const char*, charT*) const;
char narrow(charT, char) const;
const charT* narrow(const charT*, const charT*,
char, char*) const;
static locale::id id;
protected:
~ctype(); // virtual
virtual bool do_is(mask, charT) const;
virtual const charT* do_is(const charT*,
const charT*,
mask*) const;
virtual const charT* do_scan_is(mask,
const charT*,
const charT*) const;
virtual const charT* do_scan_not(mask,
const charT*,
const charT*) const;
virtual charT do_toupper(charT) const;
virtual const charT* do_toupper(charT*,
const charT*) const;
virtual charT do_tolower(charT) const;
virtual const charT* do_tolower(charT*,
const charT*) const;
virtual charT do_widen(char) const;
virtual const char* do_widen(const char*,
const char*,
charT*) const;
virtual char do_narrow(charT, char) const;
virtual const charT* do_narrow(const charT*,
const charT*,
char, char*) const;
};
TYPES
char_type
Type of character the facet is instantiated on.
CONSTRUCTORS
explicit ctype(size_t refs = 0)
Construct a ctype facet. If the refs argument is 0, then destruction of the
object is delegated to the locale, or locales, containing it. This allows
the user to ignore lifetime management issues. On the other hand, if refs
is 1, then the object must be explicitly deleted; the locale does not do
so.
DESTRUCTORS
~ctype(); // virtual and protected
Destroy the facet.
PUBLIC MEMBER FUNCTIONS
The public members of the ctype facet include an interface to protected
members. Each public member xxx has a corresponding virtual protected
member do_xxx. All work is delegated to these protected members. For
instance, the public widen function simply calls its protected cousin
do_widen.
bool
is(mask m, charT c) const;
const charT*
is(const charT* low,
const charT* high, mask* vec) const;
Returns do_is(m,c) or do_is(low,high,vec).
charnarrow(charT c, char dfault) const;
const charT*narrow(const charT* low, const charT*, char dfault,
char* to) const;
Returns do_narrow(c,dfault) or do_narrow(low,high,dfault,to).
const charT*scan_is(mask m, const charT*, const charT* high) const;
Returns do_scan_is(m,low,high).
const charT*scan_not(mask m, const charT* low, const charT* high) const;
Returns do_scan_not(m,low,high).
charTtolower(charT c) const;
const charT*tolower(charT* low, const charT* high) const;
Returns do_tolower(c) or do_tolower(low,high).
charTtoupper(charT) const;
const charT*toupper(charT* low, const charT* high) const;
Returns do_toupper(c) or do_toupper(low,high).
charTwiden(char c) const;
const char*widen(const char* low, const char* high, charT* to) const;
Returns do_widen(c) or do_widen(low,high,to).
FACET ID
static locale::id id;
Unique identifier for this type of facet.
PROTECTED MEMBER FUNCTIONS
virtual bool
do_is(mask m, charT c) const;
Returns true if c matches the classification indicated by the mask m, where
m is one of the values available from ctype_base. For instance, the follow‐
ing call returns true since `a' is an alphabetic character:
ctype<char>().is(ctype_base::alpha,'a');
See ctype_base for a description of the masks.
virtual const charT*do_is(const charT* low, const charT* high,
mask* vec) const;
Fills vec with every mask from ctype_base that applies to the range of
characters indicated by [low,high). See ctype_base for a description of
the masks. For instance, after the following call, the first five entries
in the array v would each contain the mask value:
alpha|lower|print|alnum|graph:
char a[] = "abcde";
ctype_base::mask v[12];
ctype<char>().is(a,a+5,v);
Returns high.
virtual chardo_narrow(charT, char dfault) const;
Returns the appropriate char representation for c, if such exists. Other‐
wise do_narrow returns dfault.
virtual const charT*do_narrow(const charT* low, const charT* high,
char dfault, char* dest) const;
Converts each character in the range [low,high) to its char representation,
if such exists. If a char representation is not available, then the charac‐
ter is converted to dfault. Returns high.
virtual const charT*do_scan_is(mask m, const charT* low, const charT* high) const;
Finds the first character in the range [low,high) that matches the classi‐
fication indicated by the mask m.
virtual const charT*do_scan_not(mask m, const charT* low, const charT* high) const;
Finds the first character in the range [low,high) that does not match the
classification indicated by the mask m.
virtual charTdo_tolower(charT) const;
Returns the lower case representation of c, if such exists. Otherwise
returns c.
virtual const charT*do_tolower(charT* low, const charT* high) const;
Converts each character in the range [low,high) to its lower case represen‐
tation, if such exists. If a lower case representation does not exist, then
the character is not changed. Returns high.
virtual charTdo_toupper(charT c) const;
Returns the upper case representation of c, if such exists. Otherwise
returns c.
virtual const charT*do_toupper(charT* low, const charT* high) const;
Converts each character in the range [low,high) to its upper case represen‐
tation, if such exists. If an upper case representation does not exist,
then the character is not changed. Returns high.
virtual charTdo_widen(char c) const;
Returns the appropriate charT representation for c.
virtual const char*do_widen(const char* low, const char* high, charT* dest) const;
Converts each character in the range [low,high) to its charT representa‐
tion. Returns high.
EXAMPLE
//
// ctype.cpp
//
#include <iostream>
int main ()
{
using namespace std;
locale loc;
string s1("blues Power");
// Get a reference to the ctype<char> facet
const ctype<char>& ct =
#ifndef _RWSTD_NO_TEMPLATE_ON_RETURN_TYPE
use_facet<ctype<char> >(loc);
#else
use_facet(loc,(ctype<char>*)0);
#endif
// Check the classification of the 'a' character
cout << ct.is(ctype_base::alpha,'a') << endl;
cout << ct.is(ctype_base::punct,'a') << endl;
// Scan for the first upper case character
cout << (char)*(ct.scan_is(ctype_base::upper,
s1.begin(),s1.end())) << endl;
// Convert characters to upper case
ct.toupper(s1.begin(),s1.end());
cout << s1 << endl;
return 0;
}
SEE ALSO
locale, facets, collate, ctype_byname
NAME
ctype<char>
- A specialization of the ctype facet.
SYNOPSIS
#include <locale>
class ctype<char>;
DESCRIPTION
This specialization of the ctype<charT> template includes inline ver‐
sions of ctype's member functions. The facet has the same public inter‐
face and uses the same set of masks as the ctype template.
INTERFACE
template <>
class ctype<char> : public locale::facet, public ctype_base {
public:
typedef char char_type;
explicit ctype(const mask* = 0, bool = false,
size_t = 0);
bool is(mask, char) const;
const char* is(const char*,
const char*, mask*) const;
const char* scan_is(mask,
const char*,
const char*) const;
const char* scan_not(mask,
const char*,
const char*) const;
char toupper(char) const;
const char* toupper(char*, const char*) const;
char tolower(char) const;
const char* tolower(char*, const char*) const;
char widen(char) const;
const char* widen(const char*,
const char*, char*) const;
char narrow(char, char) const;
const char* narrow(const char*, const char*,
char, char*) const;
static locale::id id;
static const size_t table_size = 256;
protected:
const mask* table() const throw();
static const mask* classic_table()throw();
~ctype(); // virtual
virtual char do_toupper(char) const;
virtual const char* do_toupper(char*,
const char*) const;
virtual char do_tolower(char) const;
virtual const char* do_tolower(char*,
const char*) const;
};
TYPES
char_type
Type of character the facet is instantiated on.
CONSTRUCTORS
explicit ctype(const mask* tbl = 0, bool del = false,
size_t refs = 0)
Construct a ctype facet. The three parameters set up the following condi‐
tions:
· The tbl argument must be either 0 or an array of at least table_size
elements. If tbl is non-zero, then the supplied table is used for
character classification.
· If tbl is non zero, and del is true, then the tbl array is deleted by
the destructor, so the calling program need not concern itself with
the lifetime of the table.
· If the refs argument is 0, then destruction of the object itself is
delegated to the locale, or locales, containing it. This allows the
user to ignore lifetime management issues. On the other hand, if refs
is 1, then the object must be explicitly deleted; the locale does not
do so.
DESTRUCTORS
~ctype(); // virtual and protected
Destroy the facet. If the constructor was called with a non-zero tbl argu‐
ment and a true del argument, then the array supplied by the tbl argument
is deleted.
PUBLIC MEMBER FUNCTIONS
The public members of the ctype<char> facet specialization do not all
serve the same purpose as the functions in the template. In many cases
these functions implement functionality, rather than just forwarding a
call to a protected implementation function.
static const mask*
classic_table()throw();
Returns a pointer to a table_size character array that represents the clas‐
sifications of characters in the "C" locale.
boolis(mask m, char c) const;
Determines if the character c has the classification indicated by the mask
m. Returns table()[(unsigned char)c] and m.
const char*is(const char* low,
const char* high, mask* vec) const;
Fills vec with every mask from ctype_base_that applies to the range of
characters indicated by [low,high). See ctype_base for a description of
the masks. For instance, after the following call, the first five elements
of v would contain: alpha|lower|print|xdigit|graph}:
char a[] = "abcde";
ctype_base::mask v[12];
ctype<char>().do_is(a,a+5,v);
Returns high.charnarrow(char c, char dfault) const;
Returns c.
const char*narrow(const char* low, const char*, char dfault,
char* to) const;
Performs ::memcpy(to,low,high-low). Returns high.
const char*scan_is(mask m, const char*, const char* high) const;
Finds the first character in the range [low,high) that matches the classi‐
fication indicated by the mask m. The classification is matched by checking
for table()[(unsigned char) p] & m, where p is in the range [low,high).
Returns the first p that matches, or high if none do.
const char*scan_not(mask m, const char* low, const char* high) const;
Finds the first character in the range [low,high) that does not match the
classification indicated by the mask m. The classification is matched by
checking for !(table()[(unsigned char) p] & m), where p is in the range
[low,high). Returns the first p that matches, or high if none do.
const mask*table() const throw();
If the tbl argument that was passed to the constructor was non-zero, then
this function returns that argument. Otherwise it returns classic_table().
chartolower(char c) const;
const char*tolower(char* low, const char* high) const;
Returns do_tolower(c) or do_tolower(low,high).
chartoupper(char) const;
const char*toupper(char* low, const char* high) const;
Returns do_toupper(c) or do_toupper(low,high).
charwiden(char c) const;
Returns c.
const char*widen(const char* low, const char* high, char* to) const;
Performs ::memcpy(to,low,high-low). Returns high.
FACET ID
static locale::id id;
Unique identifier for this type of facet.
PROTECTED MEMBER FUNCTIONS
virtual char
do_tolower(char) const;
Returns the lower case representation of c, if such exists. Otherwise
returns c.
virtual const char*do_tolower(char* low, const char* high) const;
Converts each character in the range [low,high) to its lower case represen‐
tation, if such exists. If a lower case representation does not exist, then
the character is not changed. Returns high.
virtual chardo_toupper(char c) const;
Returns the upper case representation of c, if such exists. Otherwise
returns c.
virtual const char*do_toupper(char* low, const char* high) const;
Converts each character in the range [low,high) to its upper case represen‐
tation, if such exists. If an upper case representation does not exist,
then the character is not changed. Returns high.
SEE ALSO
locale, facets, collate, ctype_byname
Rogue Wave Software 02 Apr 1998 ctype(3C++)