diff options
Diffstat (limited to 'backends/saves/compressed/compressed-saves.cpp')
| -rw-r--r-- | backends/saves/compressed/compressed-saves.cpp | 35 |
1 files changed, 21 insertions, 14 deletions
diff --git a/backends/saves/compressed/compressed-saves.cpp b/backends/saves/compressed/compressed-saves.cpp index 150cf5c47d..0c4fec0e24 100644 --- a/backends/saves/compressed/compressed-saves.cpp +++ b/backends/saves/compressed/compressed-saves.cpp @@ -62,7 +62,7 @@ public: _stream.zfree = Z_NULL; _stream.opaque = Z_NULL; - // Verify file header is correct once more + // Verify file header is correct w->seek(0, SEEK_SET); uint16 header = w->readUint16BE(); assert(header == 0x1F8B || @@ -133,27 +133,34 @@ public: } void seek(int32 offset, int whence = SEEK_SET) { int32 newPos = 0; + assert(whence != SEEK_END); // SEEK_END not supported switch(whence) { - case SEEK_END: - newPos = size() - offset; - break; case SEEK_SET: newPos = offset; break; case SEEK_CUR: newPos = _pos + offset; } - offset = newPos - _pos; - - if (offset < 0) - error("Backward seeking not supported in compressed savefiles"); + + assert(newPos >= 0); + + if ((uint32)newPos < _pos) { + // To search backward, we have to restart the whole decompression + // from the start of the file. A rather wasteful operation, best + // to avoid it. :/ +#if DEBUG + warning("Backward seeking in CompressedInSaveFile detected"); +#endif + _pos = 0; + _wrapped->seek(0, SEEK_SET); + _zlibErr = inflateReset(&_stream); + if (_zlibErr != Z_OK) + return; + _stream.next_in = _buf; + _stream.avail_in = 0; + } - // We could implement backward seeking, but it is tricky to do efficiently. - // A simple solution would be to restart the whole decompression from the - // start of the file. Or we could decompress the whole file in one go - // in the constructor, and wrap it into a MemoryReadStream -- but that - // would be rather wasteful. As long as we don't need it, I'd rather not - // implement this at all. -- Fingolfin + offset = newPos - _pos; // Skip the given amount of data (very inefficient if one tries to skip // huge amounts of data, but usually client code will only skip a few |