form1.frm

操作系统中的算法模拟

VERSION 5.00
Begin VB.Form Form1 
   AutoRedraw      =   -1  'True
   Caption         =   "银行家算法"
   ClientHeight    =   9360
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   12285
   BeginProperty Font 
      Name            =   "宋体"
      Size            =   12
      Charset         =   134
      Weight          =   400
      Underline       =   0   'False
      Italic          =   0   'False
      Strikethrough   =   0   'False
   EndProperty
   LinkTopic       =   "Form1"
   ScaleHeight     =   9360
   ScaleWidth      =   12285
   StartUpPosition =   3  '窗口缺省
   Begin VB.ComboBox Combo1 
      Height          =   360
      ItemData        =   "Form1.frx":0000
      Left            =   6000
      List            =   "Form1.frx":000A
      TabIndex        =   8
      Top             =   100
      Width           =   1455
   End
   Begin VB.CommandButton Command3 
      Caption         =   "清除内容"
      Height          =   375
      Left            =   10920
      TabIndex        =   7
      Top             =   100
      Width           =   1335
   End
   Begin VB.CommandButton Command2 
      Caption         =   "检查安全性"
      Enabled         =   0   'False
      Height          =   375
      Left            =   9240
      TabIndex        =   6
      Top             =   100
      Width           =   1575
   End
   Begin VB.ListBox List1 
      Height          =   8700
      Left            =   0
      TabIndex        =   5
      Top             =   600
      Width           =   12255
   End
   Begin VB.CommandButton Command1 
      Caption         =   "进程和资源"
      Height          =   375
      Left            =   7560
      TabIndex        =   4
      Top             =   100
      Width           =   1575
   End
   Begin VB.TextBox Text2 
      Alignment       =   1  'Right Justify
      Height          =   390
      Left            =   5040
      TabIndex        =   3
      Text            =   "1"
      Top             =   100
      Width           =   855
   End
   Begin VB.TextBox Text1 
      Alignment       =   1  'Right Justify
      Height          =   390
      Left            =   2160
      TabIndex        =   2
      Text            =   "1"
      Top             =   100
      Width           =   855
   End
   Begin VB.Label Label2 
      Caption         =   "请输入进程个数："
      Height          =   255
      Left            =   3120
      TabIndex        =   1
      Top             =   200
      Width           =   1935
   End
   Begin VB.Label Label1 
      Caption         =   "请输入资源个数："
      Height          =   255
      Left            =   120
      TabIndex        =   0
      Top             =   200
      Width           =   1935
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Dim resnum() As Integer     '各资源数量
Dim max() As Integer        '进程对资源的最大需求矩阵
Dim allocate() As Integer   '进程已经获取的资源矩阵
Dim need() As Integer       '进程还需要获取的资源需求矩阵
Dim available() As Integer  '可用资源向量
Dim work() As Integer       '工作向量
Dim sec() As String         '记录安全序列
Dim psort() As String       '记录进程的排列
Public finish As Boolean    '标志进程序列是否安全向量
Public a As Integer         '资源的数目
Public b As Integer         '进程的数目
Public r As String          '存储进程的临时排列

Private Sub Command1_Click()
    Command2.Enabled = True
    '获取输入的资源数目和进程数目
    a = Int(Text1.Text)
    b = Int(Text2.Text)
    
    '根据输入的资源数目和进程数目重新定义模拟矩阵和向量的数组
    ReDim resnum(1 To a) As Integer
    ReDim available(1 To a) As Integer
    ReDim max(1 To a, 1 To b) As Integer
    ReDim allocate(1 To a, 1 To b) As Integer
    ReDim need(1 To a, 1 To b) As Integer
    
    '判断是随机获取还是手工输入，并调用相应的过程
    If Combo1.ListIndex = 0 Then
        Call random
    Else
        Call inpu
    End If
    
    '输出资源初始数及标题
    title1 = "资源数为:  "
    For i = 1 To a
        title1 = title1 + "R(" + Trim(Str(i)) + ")为" + Trim(Str(resnum(i))) + "  "
    Next i
    List1.AddItem (title1)
    
    '输出各矩阵及向量
    Call output(max(), allocate(), need(), available())

End Sub

Private Sub random()
    '随机取得各资源的数量(在b到b+10之间)
    '初始化可用资源向量，可用资源初始时等于资源总数
    For i = 1 To a
        resnum(i) = Int(b + Rnd() * 10)
        available(i) = resnum(i)
    Next i
    
    For i = 1 To a
        For j = 1 To b
            '随机获取进程对资源的最大需求(在0到资源总数之间)，获取进程 j 对资源 i 的最大需求
            max(i, j) = Int(Rnd() * resnum(i))
            
            '随机获取进程已获得的资源数(在0到资源数最大需求之间，即不超过 max(i,j)，且同时不能超过可用资源)
            allocate(i, j) = Int(Rnd() * max(i, j))
            If allocate(i, j) > available(i) Then
                allocate(i, j) = available(i)
            End If
            
            '获取进程 j 已经获取资源 i 的数量的同时，重新计算可用资源向量
            available(i) = available(i) - allocate(i, j)
            
            '计算进程还需获取的资源数
            need(i, j) = max(i, j) - allocate(i, j)
        Next j
    Next i
End Sub

Private Sub inpu()
    '输入各资源的数量
    '初始化可用资源向量，可用资源初始时等于资源总数
    Dim i As Integer
    Dim strres As String
    Dim strpro As String
    
    With Form2
    '得到进程标签的标题
    For j = 1 To b - 1
        strpro = "P" + Trim(Str(j + 1))
        
        '输入矩阵时的进程标签
        Load Form2.lpro(j)
        Form2.lpro(j).Caption = strpro
        Form2.lpro(j).Move 600, 800 + j * 120, 600, 100
    Next j
    For i = 1 To a - 1
        '得到资源标签的标题
        strres = "R" + Trim(Str(i + 1))
        
        '输入资源总数的标签
        Load Form2.lres(i)
        Form2.lres(i).Caption = strres
        Form2.lres(i).Move 1200 + 600 * i, 120, 600, 120
        
        '输入矩阵时的资源的标签
        Load Form2.lresn(i)
        Form2.lresn(i) = strres
        
        '输入资源总数的文本框
        Load Form2.txtnum(i)
        Form2.txtnum(i).Text = ""
        
        For j = 1 To b - 1
            '输入矩阵的文本框
            Load Form2.txtmax((i - 1) * (b - 1) + j)
            Load Form2.txtallo((i - 1) * (b - 1) + j)
        Next j
    Next i
    End With
    
    Form2.Show
    For i = 1 To a
        For j = 1 To b
            '随机获取进程对资源的最大需求(在0到资源总数之间)，获取进程 j 对资源 i 的最大需求
            max(i, j) = Int(Rnd() * resnum(i))
            
            '随机获取进程已获得的资源数(在0到资源数最大需求之间，即不超过 max(i,j)，且同时不能超过可用资源)
            allocate(i, j) = Int(Rnd() * max(i, j))
            If allocate(i, j) > available(i) Then
                allocate(i, j) = available(i)
            End If
            
            '获取进程 j 已经获取资源 i 的数量的同时，重新计算可用资源向量
            available(i) = available(i) - allocate(i, j)
            
            '计算进程还需获取的资源数
            need(i, j) = max(i, j) - allocate(i, j)
        Next j
    Next i
End Sub

Public Sub output(maxr() As Integer, allor() As Integer, needr() As Integer, avair() As Integer)
    '输出某时刻标题、各矩阵及向量
    
    '标题
    title2 = "   " + Space(Int(2 * a)) + "max" + Space(4 * a - 4) + "allocate" + Space(4 * a - 4) + "need" + Space(4 * a - 4) + "available"
    For i = 1 To a
        title3 = title3 + "R" + Trim(Str(i)) + "  "
    Next i
    title3 = "     " + title3 + "  " + title3 + "  " + title3 + "  " + title3
    List1.AddItem (title2)
    List1.AddItem (title3)
    
    '各矩阵及向量
    ReDim ss(b - 1) As String
    For j = 1 To b
        ss(j - 1) = "P" + Trim(Str(j))
        For i = 1 To a
            ss(j - 1) = ss(j - 1) + "   " + Trim(Str(maxr(i, j)))
        Next i
        ss(j - 1) = ss(j - 1) + "  "
        For i = 1 To a
            ss(j - 1) = ss(j - 1) + "   " + Trim(Str(allor(i, j)))
        Next i
        ss(j - 1) = ss(j - 1) + "  "
        For i = 1 To a
            ss(j - 1) = ss(j - 1) + "   " + Trim(Str(needr(i, j)))
        Next i
        ss(j - 1) = ss(j - 1) + "  "
        For i = 1 To a
            ss(j - 1) = ss(j - 1) + "   " + Trim(Str(avair(i)))
        Next i
    Next j
    For i = 0 To b - 1
        List1.AddItem (ss(i))
    Next i
    List1.AddItem ("")
End Sub

Public Sub secu(procsort As String)
    '安全性检查

    ReDim work(1 To a) As Integer
    Dim pn As Integer
    Dim secpn As Integer
    Dim count As Integer
    
    For i = 1 To a
        work(i) = available(i)
    Next i
    
    finish = False

    count = 1
    Do While count <= Len(procsort)
        secpn = 0
        pn = Int(Mid(procsort, count, 1))
        For i = 1 To a
            If need(i, pn) <= work(i) Then
                work(i) = work(i) + allocate(i, pn)
                secpn = secpn + 1
            Else
                Exit For
            End If
        Next i
        If secpn = a Then
            count = count + 1
        Else
            count = 10 + b
        End If
    Loop
    
    If count = b + 1 Then
        finish = True
    End If
    
End Sub

Public Sub sortproc(s As String, t As String, ByRef k As Integer)
    Dim i As Integer
    Dim ll As String
    If s <> "" Then
        For i = 1 To Len(s)
            r = t + Mid(s, i, 1)
            ll = Left(s, i - 1) + Right(s, Len(s) - i)
            Call sortproc(ll, r, k)
            r = Left(r, Len(r) - 1)
        Next i
    Else
        psort(k) = r
        k = k + 1
    End If
End Sub

Private Sub Command2_Click()
    '检查进程序列的安全性
    
    '得到进程的可能序列
    Dim x As Integer        '总共有多少种排列
    Dim ss As String        '资源的初始排列字符串
    Dim j As Integer        '代表序列的序号
    Dim pnum As Integer     '代表安全序列的序号
    Dim secproc As Boolean  '进程序列是否安全
    
    '计算 b 种资源的可排列的数目
    x = 1
    For i = 1 To b
        x = x * i
    Next i
    
    ReDim psort(x - 1) As String
    ReDim sec(x - 1) As String
    
    '用数字表示初始的资源字符串排列
    For i = 1 To b
        ss = ss + Trim(Str(i))
    Next i
    
    '将所有的进程排列序列放到数组 psort 中
    Call sortproc(ss, "", 0)
    
    '检查进程排列的安全性
    punm = 0
    For j = 0 To x - 1
        Call secu(psort(j))
        If finish = True Then
            sec(pnum) = psort(j)
            pnum = pnum + 1
        End If
    Next j
    
    '输出安全序列
    Dim secstr As String
    ReDim avai(1 To a) As Integer
    ReDim allo(1 To a, 1 To b) As Integer
    ReDim ne(1 To a, 1 To b) As Integer
    If pnum = 0 Then
        List1.AddItem ("没有安全序列，即此时系统是不安全的")
    Else
        List1.AddItem ("此时系统是安全的，安全进程执行序列有：")
        List1.AddItem ("")
        For i = 0 To pnum - 1
            secstr = "当前安全序列为： "
            For j = 1 To b
                secstr = secstr + "P" + Mid(sec(i), j, 1) + "  "
            Next j
            List1.AddItem (secstr)
            For rr = 1 To a
                avai(rr) = available(rr)
                For p = 1 To b
                    allo(rr, p) = allocate(rr, p)
                    ne(rr, p) = need(rr, p)
                Next p
            Next rr
            For k = 1 To b
                List1.AddItem ("执行完进程 P" + Mid(sec(i), k, 1) + " 后的资源分布情况是：")
                For x = 1 To a
                    avai(x) = avai(x) + ne(x, Int(Mid(sec(i), k, 1)))
                    ne(x, Int(Mid(sec(i), k, 1))) = 0
                    allo(x, Int(Mid(sec(i), k, 1))) = max(x, Int(Mid(sec(i), k, 1)))
                Next x
                Call output(max(), allo(), ne(), avai())
            Next k
        Next i
    End If
    
End Sub

Private Sub Command3_Click()
    List1.Clear
End Sub

Private Sub Form_Load()
    Combo1.ListIndex = 0
End Sub

Private Sub Form_Resize()
    Label1.Left = 120 + Int((Form1.Width - 12410) / 2)
    Text1.Left = 2160 + Int((Form1.Width - 12410) / 2)
    Label2.Left = 3120 + Int((Form1.Width - 12410) / 2)
    Text2.Left = 5040 + Int((Form1.Width - 12410) / 2)
    Combo1.Left = 6000 + Int((Form1.Width - 12410) / 2)
    Command1.Left = 7560 + Int((Form1.Width - 12410) / 2)
    Command2.Left = 9240 + Int((Form1.Width - 12410) / 2)
    Command3.Left = 10920 + Int((Form1.Width - 12410) / 2)
    List1.Width = Form1.Width - 120
    List1.Height = Form1.Height - 1130
End Sub