bslfmt_formattercharutil.h

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/// @file bslfmt_formattercharutil.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bslfmt_formattercharutil.h                                         -*-C++-*-
 
#ifndef INCLUDED_BSLFMT_FORMATTERCHARUTIL
#define INCLUDED_BSLFMT_FORMATTERCHARUTIL
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bslfmt_formattercharutil bslfmt_formattercharutil
/// @brief  Character conversion utilities for `bsl::format`.
/// @addtogroup bsl
/// @{
/// @addtogroup bslfmt
/// @{
/// @addtogroup bslfmt_formattercharutil
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bslfmt_formattercharutil-purpose"> Purpose</a>
/// * <a href="#bslfmt_formattercharutil-classes"> Classes </a>
/// * <a href="#bslfmt_formattercharutil-description"> Description </a>
///   * <a href="#bslfmt_formattercharutil-usage"> Usage </a>
///     * <a href="#bslfmt_formattercharutil-example-outputting-a-hexadecimal-in-upper-case"> Example: Outputting A Hexadecimal In Upper Case </a>
///
/// # Purpose {#bslfmt_formattercharutil-purpose}
/// Character conversion utilities for `bsl::format`.
///
/// # Classes {#bslfmt_formattercharutil-classes}
///
/// -  bslfmt::FormatterCharUtil: utilities to perform character conversions
///
/// # Description {#bslfmt_formattercharutil-description}
/// This component provides a `FormatterCharUtil` `struct` template
/// that is a namespace for utility functions that convert characters (e.g. from
/// `char` to `wchar_t` or lowercase characters to uppercase).
///
/// ## Usage {#bslfmt_formattercharutil-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example: Outputting A Hexadecimal In Upper Case {#bslfmt_formattercharutil-example-outputting-a-hexadecimal-in-upper-case}
///
///
/// Suppose we need to output a hexadecimal number to some object (e.g. some
/// character buffer) represented by the output iterator.  Additionally, we are
/// required to have the number displayed in uppercase.
/// @code
///  char         number[]     = "0x12cd";
///  const size_t sourceLength = sizeof(number) - 1;
/// @endcode
/// First, we convert the number to uppercase in place and verify the result:
/// @code
///  bslfmt::FormatterCharUtil<char>::toUpper(number, number + sourceLength);
///  const char *expectedUppercaseNumber = "0X12CD";
///  assert(0 == strcmp(number, expectedUppercaseNumber));
/// @endcode
/// Next, we output this uppercase number to the destination, using
/// `outputFromChar` function.  `OutputIterator` in this example is just a
/// primitive class that minimally satisfies the requirements of the output
/// iterator.
/// @code
///  char destination[8];
///  memset(destination, 0, sizeof(destination));
///  OutputIterator<char> charIt(destination);
///
///  charIt = bslfmt::FormatterCharUtil<char>::outputFromChar(
///                                                       number,
///                                                       number + sourceLength,
///                                                       charIt);
///
///  assert(destination + sourceLength == charIt.ptr());
///  assert(0 == strcmp(number, destination));
/// @endcode
/// Finally, we demonstrate the main purpose of these functions - to unify the
/// output of values to character strings and wide character strings.  All we
/// need to do is just change the template parameter:
/// @code
///  wchar_t wDestination[8];
///  memset(wDestination, 0, sizeof(wchar_t) * 8);
///
///  wchar_t wcharExpected[] = L"0X12CD";
///
///  OutputIterator<wchar_t> wcharIt(wDestination);
///  wcharIt = bslfmt::FormatterCharUtil<wchar_t>::outputFromChar(
///                                                       number,
///                                                       number + sourceLength,
///                                                       wcharIt);
///  assert(wDestination + sourceLength == wcharIt.ptr());
///  assert(0 == wcscmp(wcharExpected, wDestination));
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bsl
 * @{
 */
/** @addtogroup bslfmt
 * @{
 */
/** @addtogroup bslfmt_formattercharutil
 * @{
 */
 
#include <bslscm_version.h>
 
#include <bslmf_assert.h>
#include <bslmf_issame.h>
 
#include <bsls_assert.h>
 
#include <bslstl_algorithm.h>
#include <bslstl_iterator.h>
 
#include <locale>     // for 'std::ctype', 'locale'
 
 
namespace bslfmt {
 
                         // ========================
                         // struct FormatterCharUtil
                         // ========================
 
/// This struct provides a namespace for a utility functions that convert
/// characters (e.g. `char` to `wchar_t` or lowercase characters to uppercase).
/// Notice that this structure has specializations only for `char` and
/// `wchar_t` types.
///
/// See @ref bslfmt_formattercharutil 
template <class t_CHAR>
struct FormatterCharUtil {
};
 
/// This is a specialization of `FormatterCharUtil` template providing utility
/// functions for outputting data to the objects specialized by `char` type and
/// referred by the corresponding output iterator.
template <>
struct FormatterCharUtil<char> {
    // CLASS METHODS
 
    /// Output to the specified output iterator `out` the character sequence
    /// starting at the specified `begin` address and ending immediately before
    /// the specified `end` address.  Return `out` incremented by the number of characters written.  
    /// 
    /// \pre The behavior is undefined   unless `begin <= end`.
    template <class t_ITERATOR>
    static t_ITERATOR outputFromChar(const char *begin,
                                     const char *end,
                                     t_ITERATOR  out);
 
    /// Output to the specified output iterator `out` the specified `value`.
    /// Return incremented `out`.
    template <class t_ITERATOR>
    static t_ITERATOR outputFromChar(const char value, t_ITERATOR out);
 
    /// Convert all characters in the sequence starting at the specified
    /// `begin` address and ending immediately before the specified `end` address to uppercase.  
    /// Note that  conversion happens in-place.  
    /// 
    /// \pre The behavior is undefined   unless `begin <= end`.
    static void toUpper(char *begin, const char *end);
};
 
/// This is a specialization of `FormatterCharUtil` template providing utility
/// functions for outputting data to the objects specialized by `wchar_t` type
/// and referred by the corresponding output iterator.
template <>
struct FormatterCharUtil<wchar_t> {
    // CLASS METHODS
 
    /// Output to the specified output iterator `out` the character sequence
    /// starting at the specified `begin` address and ending immediately before
    /// the specified `end` address.  Return `out` incremented by the number of characters written.  
    /// 
    /// \pre The behavior is undefined   unless `begin <= end`. 
    /// 
    /// \note Note that   in case of a negative input character the outputted result is
    /// unspecified.
    template <class t_ITERATOR>
    static t_ITERATOR outputFromChar(const char *begin,
                                     const char *end,
                                     t_ITERATOR  out);
 
    /// Output to the specified output iterator `out` the specified `value`. Return incremented `out`.  
    /// 
    /// \note Note that   in case of a negative input
    /// character the outputted result is unspecified.
    template <class t_ITERATOR>
    static t_ITERATOR outputFromChar(const char value, t_ITERATOR out);
};
 
// ============================================================================
//                           INLINE DEFINITIONS
// ============================================================================
 
                         // ------------------------
                         // struct FormatterCharUtil
                         // ------------------------
// CLASS METHODS
template <class t_ITERATOR>
t_ITERATOR FormatterCharUtil<char>::outputFromChar(const char *begin,
                                                   const char *end,
                                                   t_ITERATOR  out)
{
    BSLS_ASSERT(begin <= end);
 
    typedef typename bsl::iterator_traits<t_ITERATOR>::value_type ValueType;
    BSLMF_ASSERT((bsl::is_same<ValueType, char>::value) ||
                 (bsl::is_same<ValueType, void>::value));
 
    return bsl::copy(begin, end, out);
}
 
template <class t_ITERATOR>
t_ITERATOR FormatterCharUtil<char>::outputFromChar(const char value,
                                                   t_ITERATOR out)
{
    typedef typename bsl::iterator_traits<t_ITERATOR>::value_type ValueType;
    BSLMF_ASSERT((bsl::is_same<ValueType, char>::value) ||
                 (bsl::is_same<ValueType, void>::value));
 
    *out++ = value;
 
    return out;
}
 
inline
void FormatterCharUtil<char>::toUpper(char *begin, const char *end)
{
    BSLS_ASSERT(begin <= end);
 
    for (; begin != end; (void)++begin) {
        if (*begin >= 'a' && *begin <= 'z') {
            *begin = static_cast<char>(*begin + 'A' - 'a');
        }
    }
}
 
template <class t_ITERATOR>
t_ITERATOR FormatterCharUtil<wchar_t>::outputFromChar(const char *begin,
                                                      const char *end,
                                                      t_ITERATOR  out)
{
    BSLS_ASSERT(begin <= end);
 
    typedef typename bsl::iterator_traits<t_ITERATOR>::value_type ValueType;
    BSLMF_ASSERT((bsl::is_same<ValueType, wchar_t>::value) ||
                 (bsl::is_same<ValueType, void>::value));
 
    static const std::ctype<wchar_t>& ct =
                  std::use_facet<std::ctype<wchar_t> >(std::locale::classic());
 
    for (; begin != end; (void)++begin, (void)++out) {
 
        BSLS_ASSERT(0 <= *begin);
 
        *out = ct.widen(*begin);
    }
 
    return out;
}
 
template <class t_ITERATOR>
t_ITERATOR FormatterCharUtil<wchar_t>::outputFromChar(const char value,
                                                      t_ITERATOR out)
{
    typedef typename bsl::iterator_traits<t_ITERATOR>::value_type ValueType;
    BSLMF_ASSERT((bsl::is_same<ValueType, wchar_t>::value) ||
                 (bsl::is_same<ValueType, void>::value));
 
    BSLS_ASSERT(0 <= value);
 
 
    static const std::ctype<wchar_t>& ct =
                  std::use_facet<std::ctype<wchar_t> >(std::locale::classic());
 
    *out++ = ct.widen(value);
 
    return out;
}
 
}  // close package namespace
 
 
#endif  // INCLUDED_BSLFMT_FORMATTERCHARUTIL
 
// ----------------------------------------------------------------------------
// Copyright 2024 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */