bdlt_fuzzutil.h

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/// @file bdlt_fuzzutil.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bdlt_fuzzutil.h                                                    -*-C++-*-
#ifndef INCLUDED_BDLT_FUZZUTIL
#define INCLUDED_BDLT_FUZZUTIL
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bdlt_fuzzutil bdlt_fuzzutil
/// @brief  Provide creation of `bdlt` data types from fuzz data.
/// @addtogroup bdl
/// @{
/// @addtogroup bdlt
/// @{
/// @addtogroup bdlt_fuzzutil
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bdlt_fuzzutil-purpose"> Purpose</a>
/// * <a href="#bdlt_fuzzutil-classes"> Classes </a>
/// * <a href="#bdlt_fuzzutil-description"> Description </a>
///   * <a href="#bdlt_fuzzutil-usage"> Usage </a>
///     * <a href="#bdlt_fuzzutil-example-1-provide-bdlt-datetime-within-a-range"> Example 1: Provide bdlt::Datetime within a Range </a>
///
/// # Purpose {#bdlt_fuzzutil-purpose}
/// Provide creation of `bdlt` data types from fuzz data.
///
/// # Classes {#bdlt_fuzzutil-classes}
///
/// -   bdlt::FuzzUtil: functions to create `bdlt` data types from fuzz data
///
/// @see  bslim_fuzzdataview, bslim_fuzzutil
///
/// # Description {#bdlt_fuzzutil-description}
/// This component defines a struct, `bdlt::FuzzUtil`, which serves
/// as a namespace for functions to create `bdlt` date and time types from
/// supplied fuzz input data.
///
/// Effectively, given a random sequence of bytes provided by a fuzz harness,
/// like `libFuzzer`, this component can be used to generate arbitrary date and
/// time values determined by that random sequence.  This can be used to fuzz
/// test an interface using date/time values.  See the
/// [BDE fuzz-testing guide](https://bloomberg.github.io/bde/articles/fuzz_testing.html)
/// for more detail.
///
/// The operations to produce date and time types allow restrictions on ranges
/// of dates to be produced, since it is common for operations to be valid only
/// on a certain range of dates.  The same is not typically true for time and
/// time-zone offset, so operations that restrict the range of values produced
/// for those attributes are not currently provided.
///
/// ## Usage {#bdlt_fuzzutil-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Provide bdlt::Datetime within a Range {#bdlt_fuzzutil-example-1-provide-bdlt-datetime-within-a-range}
///
///
/// The provided fuzz data is here represented by an array of bytes:
/// @code
/// const uint8_t data[] = {0x8A, 0x19, 0x0D, 0x44, 0x37, 0x0D,
///                         0x38, 0x5E, 0x9B, 0xAA, 0xF3, 0xDA};
/// @endcode
/// First, we default construct a `bslim::FuzzDataView` object, `fdv`:
/// @code
/// bslim::FuzzDataView fdv(data, sizeof(data));
///
/// assert(12 == fdv.length());
/// @endcode
/// Next, we construct `Date` objects to represent the `begin` and `end` of the
/// time interval in which we wish to construct our new `Date` from the fuzz
/// data:
/// @code
///  bdlt::Date begin(1833, 5, 7);
///  bdlt::Date end(1897, 4, 3);
/// @endcode
/// Finally, we create a `Date` object, `within`, by employing @ref bdlt_fuzzutil :
/// @code
/// bdlt::Date within = bdlt::FuzzUtil::consumeDateInRange(&fdv, begin, end);
///
/// assert(begin  <= within);
/// assert(within <= end);
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bdl
 * @{
 */
/** @addtogroup bdlt
 * @{
 */
/** @addtogroup bdlt_fuzzutil
 * @{
 */
 
#include <bdlscm_version.h>
 
#include <bdlt_date.h>
#include <bdlt_datetz.h>
#include <bdlt_time.h>
#include <bdlt_timetz.h>
#include <bdlt_datetime.h>
#include <bdlt_datetimetz.h>
 
#include <bslim_fuzzdataview.h>
#include <bslim_fuzzutil.h>
 
 
namespace bdlt {
 
                            // ===============
                            // struct FuzzUtil
                            // ===============
 
/// This utility `struct` provides a namespace for a suite of functions that
/// produce objects of date and time values from fuzz data.
///
/// See @ref bdlt_fuzzutil 
struct FuzzUtil {
 
  private:
    // PRIVATE CLASS METHODS
 
    /// Return the first valid date represented by `Date` objects.
    static Date firstValidDate();
 
    /// Return the last valid date represented by `Date` objects.
    static Date lastValidDate();
 
  public:
    // CLASS METHODS
 
    /// Return a `Date` based on the next bytes from the specified
    /// `fuzzDataView`, and update `fuzzDataView` to reflect the bytes
    /// consumed.
    static bdlt::Date consumeDate(bslim::FuzzDataView *fuzzDataView);
 
    /// Return a `Date` between the specified `begin` and `end` dates based
    /// on the next bytes from the specified `fuzzDataView`, and update
    /// `fuzzDataView` to reflect the bytes consumed.  
    /// 
    /// \pre The behavior is undefined   unless `begin <= end`.
    static bdlt::Date consumeDateInRange(bslim::FuzzDataView *fuzzDataView,
                                         const bdlt::Date&    begin,
                                         const bdlt::Date&    end);
 
    /// Return a `DateTz` based on the next bytes from the specified
    /// `fuzzDataView`, and update `fuzzDataView` to reflect the bytes
    /// consumed.
    static DateTz consumeDateTz(bslim::FuzzDataView *fuzzDataView);
 
    /// Return a `DateTz` whose `localDate()` is between the specified `begin`
    /// and `end` dates based on the next bytes from the specified
    /// `fuzzDataView`, and update `fuzzDataView` to reflect the bytes consumed.  
    /// 
    /// \pre The behavior is undefined   unless `begin <= end`.
    static DateTz consumeDateTzInRange(bslim::FuzzDataView *fuzzDataView,
                                       const bdlt::Date&    begin,
                                       const bdlt::Date&    end);
 
    /// Return a `Datetime` based on the next bytes from the specified
    /// `fuzzDataView`, and update `fuzzDataView` to reflect the bytes
    /// consumed.
    static Datetime consumeDatetime(bslim::FuzzDataView *fuzzDataView);
 
    /// Return a `Datetime` whose `date()` is between the specified `begin` and
    /// `end` dates based on the next bytes from the specified `fuzzDataView`,
    /// and update `fuzzDataView` to reflect the bytes consumed.  
    /// 
    /// \pre The behavior is undefined   unless `begin <= end`.
    static Datetime consumeDatetimeInRange(bslim::FuzzDataView *fuzzDataView,
                                           const bdlt::Date&    begin,
                                           const bdlt::Date&    end);
 
    /// Return a `DatetimeTz` based on the next bytes from the specified
    /// `fuzzDataView`, and update `fuzzDataView` to reflect the bytes
    /// consumed.
    static DatetimeTz consumeDatetimeTz(bslim::FuzzDataView *fuzzDataView);
 
    /// Return a `DatetimeTz` whose `dateTz().localDate()` is between the
    /// specified `begin` and `end` dates based on the next bytes from the
    /// specified `fuzzDataView`, and update `fuzzDataView` to reflect the bytes consumed.  
    /// 
    /// \pre The behavior is undefined   unless `begin <= end`.
    static DatetimeTz consumeDatetimeTzInRange(
                                             bslim::FuzzDataView *fuzzDataView,
                                             const bdlt::Date&    begin,
                                             const bdlt::Date&    end);
 
    /// Return a `Time` based on the next bytes from the specified
    /// `fuzzDataView`, and update `fuzzDataView` to reflect the bytes
    /// consumed.
    static Time consumeTime(bslim::FuzzDataView *fuzzDataView);
 
    /// Return a `TimeTz` based on the next bytes from the specified
    /// `fuzzDataView`, and update `fuzzDataView` to reflect the bytes
    /// consumed.
    static TimeTz consumeTimeTz(bslim::FuzzDataView *fuzzDataView);
 
    /// Return a timezone offset in minutes.
    static int consumeTz(bslim::FuzzDataView *fuzzDataView);
};
 
// ============================================================================
//                            INLINE DEFINITIONS
// ============================================================================
 
                              // ---------------
                              // struct FuzzUtil
                              // ---------------
 
// PRIVATE CLASS METHODS
inline
Date FuzzUtil::firstValidDate()
{
    return Date();
}
 
inline
Date FuzzUtil::lastValidDate()
{
    return Date(9999, 12, 31);
}
 
// CLASS METHODS
inline
bdlt::Date FuzzUtil::consumeDate(bslim::FuzzDataView *fuzzDataView)
{
    return consumeDateInRange(fuzzDataView, firstValidDate(), lastValidDate());
}
 
inline
bdlt::Date FuzzUtil::consumeDateInRange(bslim::FuzzDataView *fuzzDataView,
                                        const bdlt::Date&    begin,
                                        const bdlt::Date&    end)
{
    int beginDays = begin - firstValidDate();
    int endDays   = end - firstValidDate();
 
    int dateBetween = bslim::FuzzUtil::consumeNumberInRange<int>(
        fuzzDataView, beginDays, endDays);
 
    return firstValidDate() + dateBetween;
}
 
inline
int FuzzUtil::consumeTz(bslim::FuzzDataView *fuzzDataView)
{
    const short maxTz = 24 * 60 - 1,  // (-24, 24) hours
                minTz = -maxTz;
    return bslim::FuzzUtil::consumeNumberInRange<short>(fuzzDataView,
                                                        minTz,
                                                        maxTz);
}
 
}  // close package namespace
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2021 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 ----------------------------------
 
/** @} */
/** @} */
/** @} */