balxml_listparser.h

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/// @file balxml_listparser.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// balxml_listparser.h                                                -*-C++-*-
#ifndef INCLUDED_BALXML_LISTPARSER
#define INCLUDED_BALXML_LISTPARSER
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup balxml_listparser balxml_listparser
/// @brief  Provide push parser for lists.
/// @addtogroup bal
/// @{
/// @addtogroup balxml
/// @{
/// @addtogroup balxml_listparser
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#balxml_listparser-purpose"> Purpose</a>
/// * <a href="#balxml_listparser-classes"> Classes </a>
/// * <a href="#balxml_listparser-description"> Description </a>
///   * <a href="#balxml_listparser-usage"> Usage </a>
///     * <a href="#balxml_listparser-example-1-basic-usage"> Example 1: Basic Usage </a>
///
/// # Purpose {#balxml_listparser-purpose}
/// Provide push parser for lists.
///
/// # Classes {#balxml_listparser-classes}
///
/// -   balxml::ListParser: push parser for lists
///
/// @see  bdlat_arrayfunctions
///
/// # Description {#balxml_listparser-description}
/// The `balxml::ListParser` class template provided by this
/// component can be used to parse lists into an object that supports
/// `bdlat_ArrayFunctions`.
///
/// This class template is a model of the `PushParser` concept, which contains
/// the following methods:
/// @code
/// int beginParse(TYPE *object);
///     // Prepare the parser to start parsing a new value and associate the
///     // specified 'object' with the parser.  Return 0 if successful and
///     // non-zero otherwise.
///
/// int endParse();
///     // Ends the parse operation and store the value parsed from the pushed
///     // characters into the associated object.  Return 0 if successful and
///     // non-zero otherwise.  The behavior is undefined unless an object is
///     // associated with this parser.  Upon successful completion, the parser
///     // will be disassociated with the object.
///
/// template <typename INPUT_ITERATOR>
/// int pushCharacters(INPUT_ITERATOR begin, INPUT_ITERATOR end);
///     // Push the characters ranging from the specified 'begin' up to (but
///     // not including) the specified 'end' into this parser.  Return 0 if
///     // successful and non-zero otherwise.  The parameterized
///     // 'INPUT_ITERATOR' must be dereferenceable to a 'char' value.  The
///     // behavior is undefined unless an object is associated with this
///     // parser.
/// @endcode
///
/// ## Usage {#balxml_listparser-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Basic Usage {#balxml_listparser-example-1-basic-usage}
///
///
/// The following snippets of code illustrate the usage of this component.
/// Suppose you had an input stream that contained a list of doubles.  The
/// following `loadDoublesFromListStream` function loads this data into an
/// `bsl::vector<double>`:
/// @code
/// #include <balxml_listparser.h>
///
/// #include <bdlt_date.h>
///
/// #include <istream>
/// #include <iterator>
/// #include <vector>
/// #include <sstream>
/// #include <string>
///
/// using namespace BloombergLP;
///
/// int parseDouble(double *result, const char *data, int dataLength);
///
/// int loadDoublesFromListStream(bsl::vector<double> *result,
///                               bsl::istream&        stream)
/// {
///     enum { k_FAILURE = -1 };
///
///     balxml::ListParser<bsl::vector<double> > parser(&parseDouble);
///
///     if (0 != parser.beginParse(result)) {
///         return k_FAILURE;
///     }
///
///     if (0 != parser.pushCharacters(bsl::istreambuf_iterator<char>(stream),
///                                    bsl::istreambuf_iterator<char>())) {
///         return k_FAILURE;
///     }
///
///     return parser.endParse();
/// }
/// @endcode
/// The `parseDouble` function is implemented as follows:
/// @code
/// int parseDouble(double *result, const char *data, int dataLength)
/// {
///     bsl::stringstream ss(bsl::string(data, dataLength));
///     ss >> (*result);
///     return 0;
/// }
/// @endcode
/// The following function demonstrates the `loadDoublesFromListStream`
/// function:
/// @code
/// void usageExample()
/// {
///     const char INPUT[] = "1.5 2.0 3.8 1.0";
///
///     bsl::vector<double> vec;
///     bsl::istringstream  iss(INPUT);
///
///     int result = loadDoublesFromListStream(&vec, iss);
///
///     assert(0   == result);
///     assert(4   == vec.size());
///     assert(1.5 == vec[0]);
///     assert(2.0 == vec[1]);
///     assert(3.8 == vec[2]);
///     assert(1.0 == vec[3]);
/// }
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bal
 * @{
 */
/** @addtogroup balxml
 * @{
 */
/** @addtogroup balxml_listparser
 * @{
 */
 
#include <balscm_version.h>
 
#include <bdlat_arrayfunctions.h>
 
#include <bslalg_typetraits.h>
 
#include <bdlf_bind.h>
#include <bdlf_placeholder.h>
 
#include <bdlb_chartype.h>
 
#include <bsls_assert.h>
#include <bsls_review.h>
 
#include <bsl_functional.h>
#include <bsl_memory.h>
#include <bsl_string.h>
 
 
 
namespace balxml {
                           // ======================
                           // class ListParser<TYPE>
                           // ======================
 
/// This is a push parser for lists.
///
/// See @ref balxml_listparser 
template <class TYPE>
class ListParser {
 
    // PRIVATE TYPES
    typedef typename
    bdlat_ArrayFunctions::ElementType<TYPE>::Type ElementType;
 
    struct ParseElementFunctor;
 
  public:
    // TYPES
    typedef int (*ParseElementFunction)(ElementType*, const char*, int);
    typedef bsl::function<int(ElementType*, const char*, int)>
                                                          ParseElementCallback;
 
  private:
    // PRIVATE DATA MEMBERS
    bsl::string           d_characters;            // accumulated characters
    TYPE                 *d_object_p;              // associated object
    ParseElementCallback  d_parseElementCallback;  // callback for parsing
                                                   // elements
 
  private:
    // NOT IMPLEMENTED
    ListParser(const ListParser&);
    ListParser& operator=(const ListParser&);
 
    // PRIVATE MANIPULATORS
 
    /// Append an element to the associated object having the specified
    /// `data` of the specified `dataLength`.
    int appendElement(const char *data, int dataLength);
 
  public:
    // CREATORS
 
    /// Create a parser for lists using the specified `parseElementCallback`
    /// functor to parse each element and the optionally specified
    /// `basicAllocator` for supplying memory.  If `basicAllocator` is 0,
    /// the currently installed default allocator will be used.
    explicit ListParser(ParseElementCallback  parseElementCallback,
                        bslma::Allocator     *basicAllocator = 0);
 
#ifdef DOXYGEN // Generated by compiler:
 
    ~ListParser();
        // Destroy this object.
 
#endif
 
    /// Prepare the parser to start parsing a new value and associate the
    /// specified `object` with the parser.  Return 0 if successful and
    /// non-zero otherwise.
    int beginParse(TYPE *object);
 
    /// Ends the parse operation and store the value parsed from the pushed
    /// characters into the associated object.  Return 0 if successful and non-zero otherwise.  
    /// 
    /// \pre The behavior is undefined   unless an object is
    /// associated with this parser.  Upon successful completion, the parser
    /// will be disassociated with the object.
    int endParse();
 
    /// Push the characters ranging from the specified `begin` up to (but
    /// not including) the specified `end` into this parser.  Return 0 if
    /// successful and non-zero otherwise.  The parameterized
    /// `INPUT_ITERATOR` must be dereferenceable to a `char` value.  
    /// 
    /// \pre The behavior is undefined   unless an object is associated with this
    /// parser.
    template <class INPUT_ITERATOR>
    int pushCharacters(INPUT_ITERATOR begin, INPUT_ITERATOR end);
};
 
// ============================================================================
//                            INLINE DEFINITIONS
// ============================================================================
 
                           // ----------------------
                           // class ListParser<TYPE>
                           // ----------------------
 
// PRIVATE MANIPULATORS
 
template <class TYPE>
struct ListParser<TYPE>::ParseElementFunctor {
    // PUBLIC DATA
    ParseElementCallback&  d_parseElementCallback;
    const char            *d_data;
    int                    d_dataLength;
 
    // MANIPULATORS
    int operator()(ElementType *elem)
    {
        return d_parseElementCallback(elem, d_data, d_dataLength);
    }
    template <class t_ELEM>
    int operator()(t_ELEM *)
    {
        return -1;
    }
};
 
template <class TYPE>
int ListParser<TYPE>::appendElement(const char *data, int dataLength)
{
    BSLS_ASSERT(data);
    BSLS_ASSERT(0 < dataLength);
 
    enum { k_SUCCESS = 0, k_FAILURE = -1 };
 
    const int i = static_cast<int>(bdlat_ArrayFunctions::size(*d_object_p));
 
    bdlat_ArrayFunctions::resize(d_object_p, i + 1);
 
    ParseElementFunctor parseElementFunctor = {d_parseElementCallback,
                                               data,
                                               dataLength};
 
    if (0 != bdlat_ArrayFunctions::manipulateElement(d_object_p,
                                                     parseElementFunctor,
                                                     i)) {
        // remove the new object from the array
        bdlat_ArrayFunctions::resize(d_object_p, i);
 
        return k_FAILURE;                                             // RETURN
    }
 
     return k_SUCCESS;
}
 
// CREATORS
 
template <class TYPE>
ListParser<TYPE>::ListParser(ParseElementCallback  parseElementCallback,
                             bslma::Allocator     *basicAllocator)
: d_characters(basicAllocator)
, d_object_p(0)
, d_parseElementCallback(bsl::allocator_arg_t(),
                         bsl::allocator<ParseElementCallback>(basicAllocator),
                         parseElementCallback)
{
}
 
// MANIPULATORS
 
template <class TYPE>
int ListParser<TYPE>::beginParse(TYPE *object)
{
    BSLS_ASSERT(object);
 
    enum { k_SUCCESS = 0 };
 
    d_characters.clear();
    d_object_p = object;
 
    bdlat_ArrayFunctions::resize(d_object_p, 0);
 
    return k_SUCCESS;
}
 
template <class TYPE>
int ListParser<TYPE>::endParse()
{
    BSLS_ASSERT(d_object_p);
 
    enum { k_SUCCESS = 0, k_FAILURE = -1 };
 
    if (!d_characters.empty()) {
        if (0 != appendElement(d_characters.data(),
                               static_cast<int>(d_characters.length()))) {
            return k_FAILURE;                                         // RETURN
        }
    }
 
    d_object_p = 0;
 
    return k_SUCCESS;
}
 
template <class TYPE>
template <class INPUT_ITERATOR>
int ListParser<TYPE>::pushCharacters(INPUT_ITERATOR begin, INPUT_ITERATOR end)
{
    BSLS_ASSERT(d_object_p);
 
    enum { k_SUCCESS = 0, k_FAILURE = -1 };
 
    while (begin != end) {
        const char character = *begin;
 
        ++begin;
 
        if (bdlb::CharType::isSpace(character)) {
            if (!d_characters.empty()) {
                if (0 != appendElement(
                                    d_characters.data(),
                                    static_cast<int>(d_characters.length()))) {
                    return k_FAILURE;                                 // RETURN
                }
 
                d_characters.clear();
            }
        }
        else {
            d_characters.push_back(character);
        }
    }
 
    return k_SUCCESS;
}
 
}  // close package namespace
 
 
#endif // ! defined(INCLUDED_BAEXML_LISTPARSER)
 
// ----------------------------------------------------------------------------
// Copyright 2015 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 ----------------------------------
 
/** @} */
/** @} */
/** @} */