bdljsn_numberutil.h

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/// @file bdljsn_numberutil.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bdljsn_numberutil.h                                                -*-C++-*-
#ifndef INCLUDED_BDLJSN_NUMBERUTIL
#define INCLUDED_BDLJSN_NUMBERUTIL
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bdljsn_numberutil bdljsn_numberutil
/// @brief  Provide utilities converting between JSON text and numeric types.
/// @addtogroup bdl
/// @{
/// @addtogroup bdljsn
/// @{
/// @addtogroup bdljsn_numberutil
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bdljsn_numberutil-purpose"> Purpose</a>
/// * <a href="#bdljsn_numberutil-classes"> Classes </a>
/// * <a href="#bdljsn_numberutil-description"> Description </a>
///   * <a href="#bdljsn_numberutil-usage"> Usage </a>
///     * <a href="#bdljsn_numberutil-example-1-interpreting-a-json-number-string"> Example 1: Interpreting a JSON Number String </a>
///
/// # Purpose {#bdljsn_numberutil-purpose}
/// Provide utilities converting between JSON text and numeric types.
///
/// # Classes {#bdljsn_numberutil-classes}
///
/// -  bdljsn::NumberUtil: conversion between JSON text and numeric types
///
/// # Description {#bdljsn_numberutil-description}
/// This component provides a struct, `bdljsn::NumberUtil`, that is
/// a namespace for a suite of functions for working with the JSON number text
/// format.  `bdljsn::NumberUtil` provides a function `isValidNumber` to
/// determine whether a string is a valid JSON number.  Many of the other
/// operations in this component have, as a precondition, that `isValidNumber`
/// is `true` for the text.  For information about the JSON number specification
/// and additional background on the behavior of numbers in `bdljsn` see
/// {bdljsn_jsonnumber}.
///
/// Many of the operations in this component have `isValidNumber` as a
/// precondition in order to provide simpler and more efficient implementations.
/// In the context of `JsonNumber`, the text will always be validated prior to
/// performing other operations.
///
/// ## Usage {#bdljsn_numberutil-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Interpreting a JSON Number String {#bdljsn_numberutil-example-1-interpreting-a-json-number-string}
///
///
/// This example demonstrates using `bdljsn::NumberUtil` to work with a JSON
/// number string.  Imagine we are given and array of strings for numbers we
/// expect to be integers, for each string we want to render some properties for
/// that number.
///
/// First, we define an interesting set of example data:
/// @code
/// const char *EXAMPLE_DATA[] = {
///    // value                               converted int value & notes
///    // -----                               ---------------------------
///    "NaN",                                // invalid number
///    "INF",                                // invalid number
///    "1",                                  // 1,         exact
///    "1.5",                                // 1,         not an integer
///    "-9223372036854775809",               // INT64_MIN, underflow
///    "1.5e27",                             // INT64_MAX, overflow
/// };
///
/// const int NUM_DATA = sizeof EXAMPLE_DATA / sizeof *EXAMPLE_DATA;
/// @endcode
/// Then, for each number, we first check whether it is a valid JSON Number
/// (note that the behavior for the other methods is undefined unless the text
/// is a valid JSON Number):
/// @code
/// for (int i = 0; i < NUM_DATA; ++i) {
///     const char *EXAMPLE = EXAMPLE_DATA[i];
///     bsl::cout << "\"" << EXAMPLE << "\": " << bsl::endl;
///     if (!bdljsn::NumberUtil::isValidNumber(EXAMPLE)) {
///         bsl::cout << "  * is NOT a JSON Number" << bsl::endl;
///         continue;                                               // CONTINUE
///     }
/// @endcode
/// Next we verify that the number is an integer.  This will return an accurate
/// result even when the integer cannot be represented.
/// @code
///     if (bdljsn::NumberUtil::isIntegralNumber(EXAMPLE)) {
///         bsl::cout << "  * is an integer" << bsl::endl;
///     }
///     else {
///         bsl::cout << "  * is not an integer" << bsl::endl;
///     }
/// @endcode
/// Finally, we convert that number to an integer:
/// @code
///     bsls::Types::Int64 value;
///     int                rc = bdljsn::NumberUtil::asInt64(&value, EXAMPLE);
///
///     bsl::cout << "  * value: " << value;
///
///     if (bdljsn::NumberUtil::k_NOT_INTEGRAL == rc) {
///         bsl::cout << "  (truncated)";
///     }
///     if (bdljsn::NumberUtil::k_OVERFLOW == rc) {
///         bsl::cout << "  (overflow)";
///     }
///     if (bdljsn::NumberUtil::k_UNDERFLOW == rc) {
///         bsl::cout << "  (underflow)";
///     }
///     bsl::cout << bsl::endl;
/// }
/// @endcode
/// This will output the text:
/// @code
/// "NaN":
///   * is NOT a JSON Number
/// "INF":
///   * is NOT a JSON Number
/// "1":
///   * is an integer
///   * value: 1
/// "1.5":
///   * is not an integer
///   * value: 1  (truncated)
/// "-9223372036854775809":
///   * is an integer
///   * value: -9223372036854775808  (underflow)
/// "1.5e27":
///   * is an integer
///   * value: 9223372036854775807  (overflow)
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bdl
 * @{
 */
/** @addtogroup bdljsn
 * @{
 */
/** @addtogroup bdljsn_numberutil
 * @{
 */
 
#include <bdlscm_version.h>
 
#include <bdlb_float.h>
#include <bdlb_numericparseutil.h>
#include <bdldfp_decimal.h>
#include <bdldfp_decimalimputil.h>
 
#include <bsla_nodiscard.h>
#include <bslmf_assert.h>
#include <bslmf_selecttrait.h>
 
#include <bsls_assert.h>
#include <bsls_performancehint.h>
#include <bsls_types.h>
 
#include <bsl_cerrno.h>  // `ERANGE`
#include <bsl_string.h>
#include <bsl_string_view.h>
#include <bsl_type_traits.h>
#include <bsl_iostream.h>
 
 
namespace bdljsn {
 
struct NumberUtil_ImpUtil;
 
                           // =================
                           // struct NumberUtil
                           // =================
 
/// This `struct` provides a namespace for a suite of functions that convert
/// between a JSON formated numeric value and various numerical types.  The
/// valid syntax for a JSON formatted numeric value is spelled out in
/// `https://www.rfc-editor.org/rfc/rfc8259#section-6`.
///
/// See @ref bdljsn_numberutil 
struct NumberUtil {
 
    // PUBLIC TYPES
    typedef bsls::Types::Uint64 Uint64;
    typedef bsls::Types::Int64  Int64;
 
    // PUBLIC CONSTANTS
    enum {
        // special integer conversion status values
        k_OVERFLOW     = -1,  // the number is above the representable range
        k_UNDERFLOW    = -2,  // the number is below the representable range
        k_NOT_INTEGRAL = -3,  // the number is not an integer
 
        // special exact Decimal64 conversion status values
        k_INEXACT = -4
    };
 
    // CLASS METHODS
 
           // validation
 
    /// Return `true` if the specified `value` is a valid integral JSON number.  
    /// 
    /// \note Note that   this function may return `true` even if `value`
    /// cannot be represented in a fundamental integral type.  
    /// 
    /// \pre The behavior is undefined   unless `isValidNumber(value)` is `true`.
    static bool isIntegralNumber(const bsl::string_view& value);
 
    /// Return `true` if the specified `value` is a valid JSON number.  
    /// 
    /// \note Note that   this function may return `true` even if `value` cannot be
    /// represented in any particular number type.
    static bool isValidNumber(const bsl::string_view& value);
 
           // basic floating point conversions
 
    /// Return the closest floating point representation to the specified
    /// `value`.  If `value` is outside the representable range, return +INF or -INF (as appropriate).  
    /// 
    /// \pre The behavior is undefined   unless
    /// `isValidNumber(value)` is `true`.
    static bdldfp::Decimal64 asDecimal64(const bsl::string_view& value);
    static double            asDouble   (const bsl::string_view& value);
    static float             asFloat    (const bsl::string_view& value);
 
           // exact floating point conversions
 
    /// Load the specified `result` with the specified `value`, even if a
    /// non-zero status is returned.  Return 0 if `value` can be represented
    /// exactly, and return `k_INEXACT` and load `result` with the closest
    /// approximation of `value` if `value` cannot be represented exactly.
    /// A `value` can be represented exactly as a `Decimal64` if, for the
    /// significand and exponent of `value`,
    /// `abs(significand) <= 9,999,999,999,999,999` and `-398 <= exponent <= 369`.  
    /// 
    /// \pre The behavior is undefined   unless
    /// `isValidNumber(value)` is `true`.
    static int asDecimal64Exact(bdldfp::Decimal64       *result,
                                const bsl::string_view&  value);
 
           // typed integer conversions
 
// BDE_VERIFY pragma: -FABC01 // not in alphabetic order
 
    /// Load the specified `result` with the specified `value`, even if a
    /// non-zero status is returned (truncating fractional digits if
    /// necessary).  Return 0 on success, `k_OVERFLOW` if `value` is larger
    /// than can be represented by `result`, `k_UNDERFLOW` if `value` is
    /// smaller than can be represented by `result`, and `k_NOT_INTEGRAL` if
    /// `value` is not an integral number (i.e., there is a fractional
    /// part).  For underflow, `result` will be loaded with the minimum
    /// representable value, for overflow, `result` will be loaded with the
    /// maximum representable value, for non-integral values `result` will
    /// be loaded with the integer part of `value` (truncating the fractional part of `value`).  
    /// 
    /// \pre The behavior is undefined   unless `isValidNumber(value)` is `true`.  
    /// 
    /// \note Note that   this operation will
    /// correctly handle exponents (e.g., a `value` of
    /// "0.00000000000000000001e20" will produce a `result` of 1).
    static int asShort(short           *result, const bsl::string_view& value);
    static int asUshort(unsigned short *result, const bsl::string_view& value);
    static int asInt  (int             *result, const bsl::string_view& value);
    static int asUint (unsigned int    *result, const bsl::string_view& value);
    static int asLong (long            *result, const bsl::string_view& value);
    static int asUlong(unsigned long   *result, const bsl::string_view& value);
    static int asLonglong
                   (long long          *result, const bsl::string_view& value);
    static int asUlonglong
                   (unsigned long long *result, const bsl::string_view& value);
    static int asInt64 (Int64          *result, const bsl::string_view& value);
    static int asUint64(Uint64         *result, const bsl::string_view& value);
 
// BDE_VERIFY pragma: +FABC01 // not in alphabetic order
 
            // generic integer conversion
 
    /// Load into the specified `result` (of the template parameter type
    /// `t_INTEGER_TYPE`) with the specified `value`, even if a non-zero
    /// status is returned (truncating fractional digits if necessary).
    /// Return 0 on success, `k_OVERFLOW` if `value` is larger than can be
    /// represented by `result`, `k_UNDERFLOW` if `value` is smaller than
    /// can be represented by `result`,  and `k_NOT_INTEGRAL` if `value` is
    /// not an integral number (i.e., there is a fractional part).  For
    /// underflow, `result` will be loaded with the minimum representable
    /// value, for overflow, `result` will be loaded with the maximum
    /// representable value, for non-integral values `result` will be loaded
    /// with the integer part of `value` (truncating the value to the
    /// nearest integer).  If the result is not an integer and also either
    /// overflows or underflows, it is treated as an overflow or underflow
    /// (respectively).  The (template parameter) `t_INTEGER_TYPE` shall be
    /// either a signed or unsigned integer type (that is not `bool`) where `sizeof(t_INTEGER_TYPE) <= 8`. 
    /// 
    /// \pre The behavior is undefined   unless `isValidNumber(value)` is `true`.  
    /// 
    /// \note Note that   this operation will
    /// correctly handle exponents (e.g., a `value` of
    /// "0.00000000000000000001e20" will produce a `result` of
    /// 1).
    template <class t_INTEGER_TYPE>
    static int asInteger(t_INTEGER_TYPE          *result,
                         const bsl::string_view&  value);
 
           // conversions to string
 
    /// Load into the specified `result` a string representation of
    /// specified numerical `value`.
    static void stringify(bsl::string *result, long long                value);
    static void stringify(bsl::string *result, unsigned long long       value);
    static void stringify(bsl::string *result, double                   value);
    static void stringify(bsl::string *result, const bdldfp::Decimal64& value);
 
           // comparison
 
    /// Return `true` if the specified `lhs` and `rhs` represent the same
    /// numeric value, and `false` otherwise.  This function will return
    /// `true` for differing representations of the same number (e.g.,
    /// `1.0`, "1", "0.1e+1" are all equivalent) *except* in cases where the
    /// exponent cannot be represented by a 64-bit integer.  If the exponent
    /// is outside the range of a 64-bit integer, `true` will be returned if
    /// `lhs == rhs`.  For example, comparing "1e18446744073709551615" with
    /// itself will return `true`, but comparing it to
    /// "10e18446744073709551614" will return `false`.  
    /// 
    /// \pre The behavior is undefined   unless `isValidNumber(lhs)` and `isValidNumber(rhs)`.
    static bool areEqual(const bsl::string_view& lhs,
                         const bsl::string_view& rhs);
};
 
                         // ==========================
                         // struct NumberUtil_IsSigned
                         // ==========================
 
/// This class will be a `bsl::true_type` if the specified (template
/// parameter type) `t_TYPE` is a signed type, and `bsl::false_type` otherwise.  `t_TYPE` shall be an integral type.  
/// 
/// \note Note that   currently
/// bsl::is_signed is not available for C++03 platforms.
template <class t_TYPE>
struct NumberUtil_IsSigned
: bsl::integral_constant<bool, (t_TYPE(-1) < t_TYPE(0))> {
};
 
                         // =========================
                         // struct NumberUtil_ImpUtil
                         // =========================
 
/// [**PRIVATE**] This private implementation `struct` provides a namespace
/// for a suite of functions used to help implement `NumberUtil`.  These
/// functions are private to this component and should not be used by
/// clients.
///
/// See @ref bdljsn_numberutil 
struct NumberUtil_ImpUtil {
 
    // PUBLIC CONSTANTS
    enum {
        k_EXPONENT_OUT_OF_RANGE = -1  // exponent is out of a supported range
    };
 
    // CLASS METHODS
 
    /// Load the specified `result` by appending the specified `digits` to
    /// the specified `startingValue`.  Return 0 on success,
    /// `NumberUtil::k_OVERFLOW` if the result cannot be represented in a
    /// `Uint64`.  For example, appending "345" to 12 will return a `result`
    /// of 12345.
    static int appendDigits(bsls::Types::Uint64     *result,
                            bsls::Types::Uint64      startingValue,
                            const bsl::string_view&  digits);
 
    /// These function overloads implement `NumberUtil::asInteger`, and are
    /// documented there.
    static int asInteger(bsls::Types::Uint64     *result,
                         const bsl::string_view&  value);
    template <class t_INTEGER_TYPE>
    static int asInteger(t_INTEGER_TYPE          *result,
                         const bsl::string_view&  value);
 
    /// These functions are the template dispatched implementations for the
    /// `NumberUtil_ImpUtil::asInteger` template function, and serve to
    /// distinguish the `signed` from the (default-case) `unsigned`
    /// implementation.  These functions are documented by
    /// `NumberUtil::asInteger`.
    template <class t_INTEGER_TYPE>
    static int asIntegerDispatchImp(
                                  t_INTEGER_TYPE                    *result,
                                  const bsl::string_view&            value,
                                  bslmf::SelectTraitCase<NumberUtil_IsSigned>);
    template <class t_INTEGER_TYPE>
    static int asIntegerDispatchImp(t_INTEGER_TYPE           *result,
                                    const bsl::string_view&   value,
                                    bslmf::SelectTraitCase<>);
 
    /// Decompose the specified `value` into constituent elements, loading
    /// the specified `isNegative` with a flag indicating if `value` is
    /// negative, the specified `isExponentNegative` with a flag indicating
    /// whether the exponent of `value` is negative, the specified `integer`
    /// with the integer portion of `value`, the specified `fraction` with
    /// the fraction portion of `value`, the specified `exponent` with the
    /// exponent portion of `value`, the specified `significantDigits` with
    /// the significant digits of `value`, the specified
    /// `significantDigitsBias` with a bias to add to the exponent when
    /// considering the value of the significant digits, and the
    /// `significantDigitsDotOffset` with the offset of the `.` character in
    /// `significantDigits` (if one exists).  The returned
    /// `significantDigits` may include a `.` character (whose offset into
    /// `significantDigits` is given by `significantDigitsOffset`) which
    /// should simply be ignored when considering the significant digits.
    /// If `significantDigits` does not include a `.` character,
    /// `significantDigitsOffset` will be `bsl::string_view::npos`.  
    /// 
    /// \pre The behavior is undefined   unless `NumberUtil::isValidNumber(value)` is `true`.  
    /// 
    /// \note Note that   if `significantDigits[0]` is `0` then `value`
    /// must be 0.
    ///
    /// For example, here are some examples of decompose results for an
    /// input `value` (`isNegative` and `isExpNegative` are omitted for
    /// readability):
    /// @code
    /// | value    | int   | frac  | exp | sigDigit | sigDotOff | sigBias |
    /// |----------|-------|-------|-----|----------|-----------|---------|
    /// | "0.00"   | "0"   | "00"  | ""  | "0"      | npos      | 0       |
    /// | "100e+1" | "100" | ""    | "1" | "1"      | npos      | 2       |
    /// | "0.020"  | "0"   | "020" | ""  | "2"      | npos      | -2      |
    /// | "1.12e5" | "1"   | "12"  | "5" | "1.12"   | 1         | -2      |
    /// | "34.50"  | "34"  | "50"  | ""  | "34.5"   | 2         | -1      |
    /// | "0.060"  | "0"   | "060" | ""  | "6"      | npos      | -2      |
    /// | "10e-2"  | "0"   | "1"   | "2" | "1"      | npos      | 1       |
    /// @endcode
    /// Notice that the `.` is ignored when considering `significantDigits`
    /// (so "34.5" is treated as "345", and the bias is -1).
    ///
    /// Finally, note that `significantDigits`, `significantDigitBias`, and
    /// `significantDigitsDotOffset` are useful when considering a canonical
    /// representation for a JSON Number, which consists of a whole number
    /// (with leading and trailing zeros removed) and an exponent.   This
    /// canonical representation can be used when determining whether two
    /// JSON numbers are equal.  For example, "-12.30e-4" would have a
    /// canonical representation -123e-5.  This canonical representation can
    /// be computed by taking the returned `significantDigits`, "12.3",
    /// ignoring the `.` character at `significantDigitsOffset` and
    /// incorporating `isNegative` to get the canonical significant digits
    /// -123, then combining `exponent` ("4") with `isExponentNegative` to
    /// get the exponent of -4 and then adding the returned
    /// `significantDigitsBias` of -1 to that exponent to get the canonical
    /// exponent of -5.  Combining the canonical significant digits (-123)
    /// and the canonical exponent (-5) results in the canonical
    /// representation -123e-5.
    static void decompose(
                       bool                        *isNegative,
                       bool                        *isExpNegative,
                       bsl::string_view            *integer,
                       bsl::string_view            *fraction,
                       bsl::string_view            *exponent,
                       bsl::string_view            *significantDigits,
                       bsls::Types::Int64          *significantDigitsBias,
                       bsl::string_view::size_type *significantDigitsDotOffset,
                       const bsl::string_view&      value);
 
    /// Log the specified `value` (for which `isValidNumber` should be
    /// `true`) could not be correctly parsed into a binary floating point representation.  
    /// 
    /// \note Note that   this function should be unreachable (and
    /// no test input has been found for which it is needed) but exists to
    /// record an issue in case some gap were found between the JSON number
    /// specification and the underlying floating point parsing functions
    /// (whose quality may be outside of our control and vary by platform).
    static void logUnparseableJsonNumber(const bsl::string_view& value);
};
 
// ============================================================================
//                            INLINE DEFINITIONS
// ============================================================================
 
                           // -----------------
                           // struct NumberUtil
                           // -----------------
 
// BDE_VERIFY pragma: -FABC01 // not in alphabetic order
 
inline
double NumberUtil::asDouble(const bsl::string_view& value)
{
    BSLS_ASSERT(NumberUtil::isValidNumber(value));
 
    double result;
 
    int rc = bdlb::NumericParseUtil::parseDouble(&result, value);
    if (BSLS_PERFORMANCEHINT_PREDICT_UNLIKELY(0 != rc && ERANGE != rc)) {
        // This should not be possible and no test has found a case where this
        // occurs.  However, to prevent a possible denial of service attack if
        // some gap were to be found in the implementation of low-level
        // floating point parsing functions and the JSON number spec, we
        // provide in-contract defined behavior for optimized (production)
        // builds.
 
        BSLS_ASSERT_UNREACHABLE("Unparseable JSON number");
        NumberUtil_ImpUtil::logUnparseableJsonNumber(value);
        return bsl::numeric_limits<double>::quiet_NaN();              // RETURN
    }
    return result;
}
 
inline
float NumberUtil::asFloat(const bsl::string_view& value)
{
    return static_cast<float>(asDouble(value));
}
 
inline
int NumberUtil::asShort(short *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asInt(int *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asLong(long *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asLonglong(long long *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asInt64(Int64 *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asUshort(unsigned short *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asUint(unsigned int *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asUlong(unsigned long *result, const bsl::string_view& value)
{
    return asInteger(result, value);
}
 
inline
int NumberUtil::asUlonglong(unsigned long long      *result,
                            const bsl::string_view&  value)
{
    return asInteger(result, value);
}
 
template <class t_INTEGER_TYPE>
int NumberUtil::asInteger(t_INTEGER_TYPE          *result,
                          const bsl::string_view&  value)
{
    BSLMF_ASSERT((bsl::is_integral<t_INTEGER_TYPE>::value &&
                 (sizeof(t_INTEGER_TYPE) <= 8) &&
                 !bsl::is_same<t_INTEGER_TYPE, bool>::value));
    return NumberUtil_ImpUtil::asInteger(result, value);
}
 
// BDE_VERIFY pragma: +FABC01 // not in alphabetic order
 
                         // -------------------------
                         // struct NumberUtil_ImpUtil
                         // -------------------------
 
inline
int NumberUtil_ImpUtil::asInteger(bsls::Types::Uint64     *result,
                                  const bsl::string_view&  value)
{
    return NumberUtil::asUint64(result, value);
}
 
template <class t_TYPE>
int NumberUtil_ImpUtil::asInteger(t_TYPE                  *result,
                                  const bsl::string_view&  value)
{
    BSLMF_ASSERT(bsl::is_integral<t_TYPE>::value);
 
    typedef bslmf::SelectTrait<t_TYPE, NumberUtil_IsSigned> Selection;
    return NumberUtil_ImpUtil::asIntegerDispatchImp(result,
                                                    value,
                                                    Selection());
}
 
template <class t_INTEGER_TYPE>
int NumberUtil_ImpUtil::asIntegerDispatchImp(
                           t_INTEGER_TYPE                              *result,
                           const bsl::string_view&                      value,
                           bslmf::SelectTraitCase<NumberUtil_IsSigned>)
{
    BSLMF_ASSERT(bsl::is_integral<t_INTEGER_TYPE>::value);
    BSLMF_ASSERT(bsl::numeric_limits<t_INTEGER_TYPE>::is_signed);
 
    BSLS_ASSERT(NumberUtil::isValidNumber(value));
 
    bsl::string_view positiveValue = value;
 
    bool isNegative;
    if ('-' == value[0]) {
        isNegative = true;
        positiveValue.remove_prefix(1);
    }
    else {
        isNegative = false;
    }
 
    const bsls::Types::Uint64 maxValue = static_cast<bsls::Types::Uint64>(
                                   bsl::numeric_limits<t_INTEGER_TYPE>::max());
 
    bsls::Types::Uint64 tmp;
 
    const int rc = NumberUtil::asUint64(&tmp, positiveValue);
 
    if (isNegative) {
        if (tmp > maxValue + 1) {
            *result = bsl::numeric_limits<t_INTEGER_TYPE>::min();
            return NumberUtil::k_UNDERFLOW;                           // RETURN
        }
        *result = static_cast<t_INTEGER_TYPE>(tmp * -1ll );
    }
    else {
        if (tmp > maxValue) {
            *result = static_cast<t_INTEGER_TYPE>(maxValue);
            return NumberUtil::k_OVERFLOW;                            // RETURN
        }
        *result = static_cast<t_INTEGER_TYPE>(tmp);
    }
    return rc;
}
 
template <class t_INTEGER_TYPE>
int NumberUtil_ImpUtil::asIntegerDispatchImp(t_INTEGER_TYPE           *result,
                                             const bsl::string_view&   value,
                                             bslmf::SelectTraitCase<>)
{
    BSLMF_ASSERT(bsl::is_integral<t_INTEGER_TYPE>::value);
    BSLMF_ASSERT(!bsl::numeric_limits<t_INTEGER_TYPE>::is_signed);
 
    BSLS_ASSERT(NumberUtil::isValidNumber(value));
 
    typedef bsls::Types::Uint64 Uint64;
 
    Uint64 tmp;
 
    int rc = NumberUtil::asUint64(&tmp, value);
    if (tmp >
        static_cast<Uint64>(bsl::numeric_limits<t_INTEGER_TYPE>::max())) {
        *result = bsl::numeric_limits<t_INTEGER_TYPE>::max();
        return NumberUtil::k_OVERFLOW;                                // RETURN
    }
    *result = static_cast<t_INTEGER_TYPE>(tmp);
    return rc;
}
 
}  // close package namespace
 
 
#endif  // INCLUDED_BDLJSN_NUMBERUTIL
 
// ----------------------------------------------------------------------------
// Copyright 2022 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 ----------------------------------
 
/** @} */
/** @} */
/** @} */