JojoDiff is a program that outputs the differences between two (binary) files. JPTCH can then be used to reconstruct the second file from the first file.

JDIFF tries to find a minimal set of differences between two files using a heuristic algorithm with constant space and linear time complexity. This means that accuracy is traded over speed. JDIFF will therefore, in general, not always find the smallest set of differences, but will try to be fast and will use a fixed amount of memory.

JDIFF does not compress the generated patchfile. It is recommended to do so with any compression tool you like.

Usage: jdiff [options] <original file> <new file> [<output file>]
-v Verbose (greeting, results and tips).
-vv Verbose (debug info).
-h Help (this text).
-l Listing (ascii output).
-lr Regions (ascii output).
-do Write verbose and debug info to stdout instead of stddbg.
-b Try to be better (using more memory).
-f Try to be faster: no out of buffer compares.
-ff Try to be faster: no out of buffer compares, nor pre-scanning.
-m size Size (in kB) for look-ahead buffers (default 512, 0=use OS buffers ).
-bs size Block size (in bytes) for reading from files (default 4096).
-s size Number of samples per file in MB (default 8).
-a size Number of kB to look ahead (default=same as buffer-size).
-min count Minimum number of solutions to find (default 4, max 256).
-max count Maximum number of solutions to find (default 8, max 256).

Principles:
JDIFF tries to find equal regions between two binary files using a heuristic hash algorithm and outputs the differences between both files. Heuristics are generally used for improving performance and memory usage, at the cost of accuracy. Therefore, this program may not find a minimal set of differences between files.

Notes:
Options -b, -f or -ff should be used before other options.
Accuracy may be improved by increasing the number of samples.
Sample size is always lowered to the largest n-bit prime (n < 32)
Original and new file must be random access files.
Output is sent to standard output if output file is missing.

Hint:
Do not use jdiff directly on compressed files, such as zip, gzip, rar, ...
Instead use uncompressed files, such as tar, cpio or zip-0, and then compress the jdiff's output file afterwards.

The license of this software is Free, you can free download and free use this file compare software.