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ZFunctionsOther.pas
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1 {*********************************************************}
2 { }
3 { Zeos Database Objects }
4 { Variables classes and interfaces }
5 { }
6 { Originally written by Sergey Seroukhov }
7 { }
8 {*********************************************************}
9 
10 {@********************************************************}
11 { Copyright (c) 1999-2012 Zeos Development Group }
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49 { Zeos Development Group. }
50 {********************************************************@}
51 
52 unit ZFunctionsOther;
53 
54 interface
55 
56 {$I ZCore.inc}
57 
58 uses
59  SysUtils, ZFunctions, ZExpression, ZVariant;
60 
61 {** Other functions}
62 
63 type
64 
65  {** Implements a EMPTY function. }
66  TZEmptyFunction = class (TZAbstractFunction)
67  public
68  function Execute(Stack: TZExecutionStack;
69  VariantManager: IZVariantManager): TZVariant; override;
70  end;
71 
72  {** Implements a MIN function. }
73  TZMinFunction = class (TZAbstractFunction)
74  public
75  function Execute(Stack: TZExecutionStack;
76  VariantManager: IZVariantManager): TZVariant; override;
77  end;
78 
79  {** Implements a MAX function. }
80  TZMaxFunction = class (TZAbstractFunction)
81  public
82  function Execute(Stack: TZExecutionStack;
83  VariantManager: IZVariantManager): TZVariant; override;
84  end;
85 
86  {** Implements a SUM function. }
87  TZSumFunction = class (TZAbstractFunction)
88  public
89  function Execute(Stack: TZExecutionStack;
90  VariantManager: IZVariantManager): TZVariant; override;
91  end;
92 
93  {** Implements a IIF function. }
94  TZIIFFunction = class (TZAbstractFunction)
95  public
96  function Execute(Stack: TZExecutionStack;
97  VariantManager: IZVariantManager): TZVariant; override;
98  end;
99 
100  {** Implements a CASEF function. }
101  TZCASEFFunction = class (TZAbstractFunction)
102  public
103  function Execute(Stack: TZExecutionStack;
104  VariantManager: IZVariantManager): TZVariant; override;
105  end;
106 
107 procedure AddOtherFunctions(Functions : TZFunctionsList);
108 
109 implementation
110 
111 uses
112  ZMessages;
113 
114 { TZEmptyFunction }
115 
116 {**
117  Executes this function.
118  @param Stack the stack object.
119  @param VariantManager a reference to variant processor object.
120  @returns a function value.
121 }
122 function TZEmptyFunction.Execute(Stack: TZExecutionStack;
123  VariantManager: IZVariantManager): TZVariant;
124 var
125  Value: TZVariant;
126 begin
127  CheckParamsCount(Stack, 1);
128  Value := Stack.GetParameter(1);
129  VariantManager.SetAsBoolean(Result, VariantManager.IsNull(Value));
130 end;
131 
132 { TZMinFunction }
133 
134 {**
135  Executes this function.
136  @param Stack the stack object.
137  @param VariantManager a reference to variant processor object.
138  @returns a function value.
139 }
140 function TZMinFunction.Execute(Stack: TZExecutionStack;
141  VariantManager: IZVariantManager): TZVariant;
142 var
143  I, ParamsCount: Integer;
144  Value: TZVariant;
145 begin
146  ParamsCount := VariantManager.GetAsInteger(Stack.GetParameter(0));
147  if ParamsCount < 2 then
148  raise TZExpressionError.Create(SExpectedMoreParams);
149 
150  Result := Stack.GetParameter(ParamsCount);
151  for I := 1 to ParamsCount - 1 do
152  begin
153  Value := Stack.GetParameter(I);
154  if VariantManager.Compare(Result, Value) > 0 then
155  Result := Value;
156  end;
157 end;
158 
159 { TZMaxFunction }
160 
161 {**
162  Executes this function.
163  @param Stack the stack object.
164  @param VariantManager a reference to variant processor object.
165  @returns a function value.
166 }
167 function TZMaxFunction.Execute(Stack: TZExecutionStack;
168  VariantManager: IZVariantManager): TZVariant;
169 var
170  I, ParamsCount: Integer;
171  Value: TZVariant;
172 begin
173  ParamsCount := VariantManager.GetAsInteger(Stack.GetParameter(0));
174  if ParamsCount < 2 then
175  raise TZExpressionError.Create(SExpectedMoreParams);
176 
177  Result := Stack.GetParameter(ParamsCount);
178  for I := 1 to ParamsCount - 1 do
179  begin
180  Value := Stack.GetParameter(I);
181  if VariantManager.Compare(Result, Value) < 0 then
182  Result := Value;
183  end;
184 end;
185 
186 { TZSumFunction }
187 
188 {**
189  Executes this function.
190  @param Stack the stack object.
191  @param VariantManager a reference to variant processor object.
192  @returns a function value.
193 }
194 function TZSumFunction.Execute(Stack: TZExecutionStack;
195  VariantManager: IZVariantManager): TZVariant;
196 var
197  I, ParamsCount: Integer;
198 begin
199  ParamsCount := VariantManager.GetAsInteger(Stack.GetParameter(0));
200  if ParamsCount < 2 then
201  raise TZExpressionError.Create(SExpectedMoreParams);
202 
203  Result := Stack.GetParameter(ParamsCount);
204  for I := ParamsCount - 1 downto 1 do
205  Result := VariantManager.OpAdd(Result, Stack.GetParameter(I));
206 end;
207 
208 { TZIIFFunction }
209 
210 {**
211  Executes this function.
212  @param Stack the stack object.
213  @param VariantManager a reference to variant processor object.
214  @returns a function value.
215 }
216 function TZIIFFunction.Execute(Stack: TZExecutionStack;
217  VariantManager: IZVariantManager): TZVariant;
218 begin
219  CheckParamsCount(Stack, 3);
220  if VariantManager.GetAsBoolean(Stack.GetParameter(3)) then
221  Result := Stack.GetParameter(2)
222  else
223  Result := Stack.GetParameter(1);
224 end;
225 
226 { TZCASEFFunction }
227 
228 {**
229  Executes this function.
230  @param Stack the stack object.
231  @param VariantManager a reference to variant processor object.
232  @returns a function value.
233 }
234 function TZCASEFFunction.Execute(Stack: TZExecutionStack;
235  VariantManager: IZVariantManager): TZVariant;
236 var
237  ParamsCount, Index : Integer;
238 
239 begin
240  ParamsCount := VariantManager.GetAsInteger(Stack.GetParameter(0));
241  if ParamsCount < 2 then
242  raise TZExpressionError.Create(SExpectedMoreParams);
243  Index := VariantManager.GetAsInteger(Stack.GetParameter(ParamsCount));
244  if ParamsCount < (Index+2) then
245  raise TZExpressionError.Create(SExpectedMoreParams);
246  Result := Stack.GetParameter(ParamsCount-Index-1)
247 end;
248 
249 procedure AddOtherFunctions(Functions : TZFunctionsList);
250 begin
251  Functions.Add(TZEmptyFunction.Create('EMPTY'));
252  Functions.Add(TZMinFunction.Create('MIN'));
253  Functions.Add(TZMaxFunction.Create('MAX'));
254  Functions.Add(TZSumFunction.Create('SUM'));
255  Functions.Add(TZIIFFunction.Create('IIF'));
256  Functions.Add(TZCASEFFunction.Create('CASEF'));
257 end;
258 
259 end.