open-vcdiff is an encoder and decoder for the VCDIFF format, as described in
RFC 3284 : The VCDIFF Generic Differencing and Compression Data Format
(http://www.ietf.org/rfc/rfc3284.txt)

A library with a simple API is included, as well as a command-line executable
that can apply the encoder and decoder to source, target, and delta files.
For further details, please refer to:
https://github.com/google/open-vcdiff/wiki/How-to-use-openvcdiff

You will need to first synchronize gflags and gtest by running
`./fetch_prereq.bat` on Windows or `./fetch_prereq.sh` on other platforms.

See INSTALL for (generic) installation instructions for C++: basically
   ./configure && make && make install

This should compile the unit tests as well as "vcdiff", a simple command-line
utility to run the encoder and decoder.  Typical usage of vcdiff is as follows
(the "<" and ">" are file redirect operations, not optional arguments):
   vcdiff encode -dictionary file.dict < target_file > delta_file
   vcdiff decode -dictionary file.dict < delta_file > target_file
To see the command-line syntax of vcdiff, use "vcdiff --help" or just "vcdiff".

To call the encoder from C++ code, assuming that dictionary, target, and delta
are all std::string objects:
#include <google/vcencoder.h>  // Read this file for interface details
[...]
  open_vcdiff::VCDiffEncoder encoder(dictionary.data(), dictionary.size());
  encoder.SetFormatFlags(open_vcdiff::VCD_FORMAT_INTERLEAVED);
  encoder.Encode(target.data(), target.size(), &delta);

Calling the decoder is just as simple:
#include <google/vcdecoder.h>  // Read this file for interface details
[...]
  open_vcdiff::VCDiffDecoder decoder;
  decoder.Decode(dictionary.data(), dictionary.size(), delta, &target);

When using the encoder, the C++ application must be linked with the library
options -lvcdcom and -lvcdenc; when using the decoder, it must be linked with
-lvcdcom and -lvcddec.

To verify that the package works on your system, especially after making
modifications to the source code, please run the unit tests using
   make check

For further details, please refer to:
https://github.com/google/open-vcdiff/wiki/How-to-use-openvcdiff
