xdelta

Xdelta-3.0s release notes:

• Faster! Several optimizations to avoid unnecessary arithmetic
• xdelta3 -1 has faster/poorer compression (xdelta3 -2 is the former configuration)
• -S djw exposes secondary compression levels as -S djw1 .. -S djw9
• Removes "source file too large for external decompression" error check
• API support for transcoding other formats into VCDIFF

Xdelta-3.0r release notes:

• Fixes an encoder crash caused by -S djw (secondary compressor) on certain data, new tests for code-length overflow
• Adds new recode command for re-encoding a delta with different secondary compression settings
• Fixes API-specific bugs related to non-blocking calls to xd3_encode_input and xd3_decode_input
• Adds new examples/encoder_decoder_test.c program for the non-blocking API

As an example of the new recode command and secondary compression options:

$ ./xdelta3 -S none -s xdelta3.h xdelta3.c OUT  # 53618 bytes
$ ./xdelta3 recode -S djw1 OUT OUT-djw1         # 51023 bytes
$ ./xdelta3 recode -S djw3 OUT OUT-djw3         # 47729 bytes
$ ./xdelta3 recode -S djw6 OUT OUT-djw6         # 45946 bytes
$ ./xdelta3 recode -S djw7 OUT OUT-djw7         # 45676 bytes
$ ./xdelta3 recode -S djw8 OUT OUT-djw8         # 45658 bytes
$ ./xdelta3 recode -S djw9 OUT OUT-djw9         # 45721 bytes

Secondary compression remains off by default. Passing -S djw is equivalent to -S djw6.