librsync  2.3.4
librsync library

The library supports four basic operations:

  1. sig: Generating the signature S of a file A .
  2. loadsig: Read a signature from a file into memory.
  3. delta: Calculating a delta D from S and a new file B.
  4. patch: Applying D to A to reconstruct B.

These are all available in three different modes:

  • Whole-file API - for applications that just want to make and use signatures and deltas on whole files with a single function call.
  • Streaming API - a "push" mode where the caller provides input and output space, and rs_job_iter() makes as much progress as it can.
  • Pull API - a "pull" mode where librsync will call application-provided callbacks to fill and empty buffers.

Other documentation pages:

The public interface to librsync is librsync.h, and other headers are internal.

The librsync tree also provides the rdiff command, which makes this functionality available to users and scripting languages.

Naming conventions

All external symbols have the prefix rs_, or RS_ in the case of preprocessor symbols. (There are some private symbols that currently don't match this, but these are considered to be bugs.)

Symbols beginning with rs__ (double underscore) are private and should not be called from outside the library.

Threaded IO

librsync may be used from threaded programs. librsync does no synchronization itself. Each job should be guarded by a monitor or used by only a single thread.

Be careful that the trace functions are safe to call from multiple threads.