source: branch/egtra-stream-without-en_dec/Classes/System/Convert.ab@ 681

Namespace System

/*!
@brief  基本型の変換を行うクラス
*/

Class Convert
Public
    /*!
    @brief  文字列を32ビット符号付き値に変換する
    @author OverTaker
    @param  文字列
    @return 32ビット符号付き値
    */
    Static Function ToInt32(value As String) As Long
        Return ToInt32(value, 10)
    End Function

    /*!
    @brief  文字列を任意の進数で32ビット符号付き値に変換する
    @author OverTaker
    @param  文字列
    @param  基数
    @return 32ビット符号付き値
    */
    Static Function ToInt32(value As String, fromBase As Long) As Long
        Dim retVal As Long
        Dim negative = False As Boolean

        Dim init = 0 As Long
        While ActiveBasic.CType.IsSpace(value[init])
            init++
        Wend

        If Detail.IsMinus(value[init]) Then
            init++
            negative = True
        End If

        Dim i As Long
        Dim n As Long
        For i = init To ELM(value.Length)
            n = Detail.NumberFromChar(value[i])
            If n < fromBase Then
                retVal += n * fromBase^(ELM(value.Length) - i)
            Else
                Throw New ArgumentOutOfRangeException("System.Convert.ToInt32: The value was out of basevalue.", "value or fromBase")
            End If
        Next
        
        If negative Then
            Return -retVal
        Else
            Return retVal
        End If
    End Function
End Class

Namespace Detail
    /*!
    @brief  文字を値に変換する
    @author OverTaker
    @param  文字
    @return 値
    */
    Function NumberFromChar(aCharacter As WCHAR) As Long
        If ActiveBasic.CType.IsDigit(aCharacter) Then
            Return aCharacter - &H30
        ElseIf ActiveBasic.CType.IsUpper(aCharacter) Then
            Return aCharacter - &H37
        ElseIf ActiveBasic.CType.IsLower(aCharacter) Then
            Return aCharacter - &H57
        Else
            Throw New ArgumentException("System.Convert.Detail: The character was invalid.", "aCharacter")
        End If
    End Function

    /*!
    @overload
    */
    Function NumberFromChar(aCharacter As CHAR) As Long
        Return NumberFromChar(ActiveBasic.CType.Detail.Widen(aCharacter))
    End Function

    /*!
    @brief  文字が-記号かどうかを調べる
    @author OverTaker
    @param  文字
    @retval True  文字は-
    @retval Flase 文字は-でない
    */
    Function IsMinus(aCharacter As WCHAR) As Boolean
        Return aCharacter = &H2D
    End Function

    /*!
    @overload
    */
    Function IsMinus(aCharacter As CHAR) As Boolean
        Return IsMinus(ActiveBasic.CType.Detail.Widen(aCharacter))
    End Function
End Namespace

End Namespace