[Linuxsampler-devel] Allowing absolute path names in SFZ - a trivial patch

[Frank N. <bea...@we...>]

Hi all,

I came across the following problem: On my harddisk, there are lots of sample
collections I grabbed from the web, and I have started writing small .sfz
files to use them in LinuxSampler.

By nature, those .sfz files would reside "near" the samples (like, in a parent
directory), but this means that the .sfz's are just as wide-spread across my
disk as the samples are. Rather than that, I wanted to have a single directory
where I can store all of them - or at least my favourites. So, the idea is to:

- Have the samples e.g. in directory very/deep/path/samples/
- Have the .sfz file in the parent, e.g. very/deep/path/collection.sfz
- Have a modified version of that collection.sfz (called collection_abs.sfz)
  that uses absolute instead of relative references to the file names
  To get that, I cooked up a tiny C program that converts all "sample="
  references in a .sfz file to their absolute path name; of course, this is
  local to my system, so I have to keep the "relative" versions around.
- Have all my sfz's in one place, like ~/SFZfiles
  -> Since I do not want multiple copies of the same files, I make these
     as symlinks to the actual SFZ files

Now, if I try to open such an "absolutified" sfz from its linked location,
LinuxSampler cannot open them since by default it will prepend the current
directory (which would in this case be ~/SFZfiles) to the file name.

I looked at the sources, and found the code in linuxsampler/src/engines/sfz/sfz.cpp (line 1275ff):

        if ("sample" == key)
        {
            std::string path = default_path + value;
            #ifndef WIN32
            for (int i = 0; i < path.length(); i++) if( path[i] == '\\') path[i] = '/';
            #endif
            path = currentDir + LinuxSampler::File::DirSeparator + path; // TODO: check for absolute path

            if(pCurDef) pCurDef->sample = path;
            return;

(aha, so the comment there tells me someone has already been thinking about
this! :-)

I tried this trivial diff:
--- sfz.cpp.orig        2012-01-22 22:52:01.000000000 +0100
+++ sfz.cpp     2012-01-23 00:03:16.000000000 +0100
@@ -1278,7 +1278,8 @@
             #ifndef WIN32
             for (int i = 0; i < path.length(); i++) if( path[i] == '\\') path[i] = '/';
             #endif
-            path = currentDir + LinuxSampler::File::DirSeparator + path; // TODO: check for absolute path
+            if (path[0] != '/')    /* only prepend currentDir if path is non-absolute */
+                   path = currentDir + LinuxSampler::File::DirSeparator + path; // TODO: check for absolute path
 
             if(pCurDef) pCurDef->sample = path;
             return;

and, well, "it works for me" (under Linux only, of course).
If this or something even more portable can be applied to the svn tree, I'd
be very grateful.

Greetings,
Frank