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Aquaria/ExternalLibs/ttvfs/VFSArchiveLoader.h
2014-04-06 19:19:33 +02:00

69 lines
2.2 KiB
C++

#ifndef VFS_ARCHIVE_LOADER_H
#define VFS_ARCHIVE_LOADER_H
#include "VFSDefines.h"
#include "VFSRefcounted.h"
VFS_NAMESPACE_START
class Dir;
class File;
class VFSLoader;
// Generic Archive loader interface that is supposed to return a valid Dir pointer when it
// was able to load 'arch' as an archive, and NULL if there was an error or the loader is
// unable to load that file type.
// 'asSubdir' - if this is true, the archive will be accessible as a folder (as in "test.zip/file.dat"),
// otherwise the files are mounted in place of the archive.
// 'ldr' - can be set to an external file loader in case the file/folder tree can not be fully generated
// at load time.
// 'opaque' - a POD struct which *must* have a `void (*)(void*, void*, const char*)`
// function pointer as first member (at offset 0).
// The struct pointer is then passed to that function, along with a pointer to an internal object,
// whatever this is. The derived loader knows what this object is - something that this callback
// will be interested in modifying, anyways. The rest of the struct can carry the data required to
// modify this object.
// The const char parameter is a string unique for each loader (to prevent accessing the pointer
// in a wrong way by the wrong loader). Example below.
class VFSArchiveLoader : public Refcounted
{
public:
virtual ~VFSArchiveLoader() {}
virtual Dir *Load(File *arch, VFSLoader **ldr, void *opaque = NULL) = 0;
};
/* A possible struct for 'opaque' would be:
struct ExampleLoadParams
{
void (*callback)(void *, void *, const char *);
const char *key;
unsigned int keylen;
};
And then the call would look like:
(Assuming PakFile is an archive file class that represents an archive)
void pakSetup(void *data, void *arch, const char *id)
{
if(strcmp(id, "pak")) // Be sure we're in the right loader.
return;
ExampleLoadParams *pm = (ExampleLoadParams*)p;
PakArchive *pak = (PakArchive*)arch;
pak->SetKey(pm->key, pm->keylen);
}
ExampleLoadParams p;
p.callback = &pakSetup;
p.key = "123456";
p.keylen = 6;
vfs.AddArchive("data.pak", false, "", &p);
Where p in turn will be passed to the PAK loader.
*/
VFS_NAMESPACE_END
#endif