How to merge entries from two TINIfile instances? - delphi

Question

Is there a way to merge entries from one TIniFile instance to another?

Answer 1

There's no single method to do so. You can do it yourself like this:
Load the INI file, let's call them A and B.
Enumerate the sections in B.
For each section in B, enumerate the name/value pairs in that section.
Add each name/value pair from B into the corresponding section in A.
When complete, save file A, which contains the entries from both files.
The methods that you'll use to enumerate file A are ReadSections and ReadSectionValues.
You'll need to decide what to do about any clashes. That is any names that appear in both files.

Answer 2

Here's a procedure which can merge two INI files together into a new output INI file:
procedure MergeIniFiles(const FromFilename, ToFilename, OutputFilename: String;
const Overwrite: Boolean);
var
IniFrom, IniTo, IniOut: TIniFile;
Sec: TStringList;
Val: TStringList;
X, Y: Integer;
S, N, V: String;
begin
IniFrom:= TIniFile.Create(FromFilename);
IniTo:= TIniFile.Create(ToFilename);
IniOut:= TIniFile.Create(OutputFilename);
Sec:= TStringList.Create;
Val:= TStringList.Create;
try
IniFrom.ReadSections(Sec);
for X := 0 to Sec.Count-1 do begin
S:= Sec[X];
IniFrom.ReadSection(S, Val);
for Y := 0 to Val.Count-1 do begin
N:= Val[Y];
V:= IniFrom.ReadString(S, N, '');
IniOut.WriteString(S, N, V);
end;
end;
IniTo.ReadSections(Sec);
for X := 0 to Sec.Count-1 do begin
S:= Sec[X];
IniTo.ReadSection(S, Val);
for Y := 0 to Val.Count-1 do begin
N:= Val[Y];
V:= IniTo.ReadString(S, N, '');
if Overwrite then begin
IniOut.WriteString(S, N, V);
end else begin
if not IniOut.ValueExists(S, N) then
IniOut.WriteString(S, N, V);
end;
end;
end;
finally
Val.Free;
Sec.Free;
IniOut.Free;
IniTo.Free;
IniFrom.Free;
end;
end;

Answer 3

What I wanted to achieve is to have an ini file in my setup program, which would be placed along with the main executable in the 'Program Files'. This ini will contain the default values for many properties of the application. So the user's actual ini file (ex. in home folder) will read the "factory" defaults from there. This approach is something like OSX's NSUserDefaults. I think that in some cases this is useful instead of just using the default value in inifile.readString(). Thank you all for your answers, I just post the final functions for this purpose...
procedure inifileLoadDefaults(const defaults: TFileName; destination:TIniFile);
var inif: TIniFile;
begin
inif := TIniFile.Create(defaults);
try
inifileLoadDefaults(inif, destination);
finally
inif.Free;
end;
end;
procedure inifileLoadDefaults(const defaults: TIniFile; destination:TIniFile);
var secs, secsVal: TStrings;
i, k: Integer;
begin
secs := TStringList.Create;
secsVal := TStringList.Create;
try
defaults.ReadSections(secs);
for i:=0 to secs.Count -1 do begin
defaults.ReadSection(secs[i], secsVal);
for k:=0 to secsVal.Count -1 do
if not(destination.ValueExists(secs[i], secsVal[k])) then
destination.WriteString(secs[i], secsVal[k], defaults.ReadString(secs[i], secsVal[k], ''));
end;
finally
secsVal.Free;
secs.Free;
end;
end;