===== About =====
cxdf (compact cross differentiation format) was developed for JuraviS in order to streamline a compact and effective format for modifying game files based on their original counterparts. This format aims to give an alternative to including copyrighted data into patch files.

===== Structure =====
All values are stored in Little-Endian.
  - Identifier [2 bytes]
    * String ''J5'' or [''0x4A'',''0x35'']
  - Version [1 byte]
    * Current Version: 0x01
  - Settings [1 byte]
    * ''00001000'': Resize on filesize mismatch
    * ''00000111'': New filesize byte count
  - Filesize [0-7 bytes, unsigned]
  - Patch Instructions [varies, multiple]

===== Patch Instructions =====

  - Header [1 byte]
    * ''11110000'': Instruction ID
    * ''00001000'':
      * 0 = Seek (absolute jump to offset)
      * 1 = Hop (relative jump from current offset)
    * ''00000111'': Seek/Hop offset byte count
  - Seek/Hop Offset [0-7 bytes, unsigned]
  - Instruction Data [varies]


==== Instruction Data ====

=== 0x0 Write Byte ===
Writes a single byte with the given value to the current offset of the modification buffer.
  - Byte Value [1 byte]

=== 0x2 Repeat Byte ===
Writes a single byte repeating for a given length to the current offset of the modification buffer.
  - Repeat count [1 byte, unsigned]
    * 1-256
  - Byte Value [1 byte]

=== 0x3 Repeat Byte (long) ===
Same as above; long version;
  - Repeat count [2 bytes, unsigned]
    * 1-65536
  - Byte Value [1 byte]

=== 0x4 Write Buffer ===
Writes a buffer of bytes to the current offset of the modification buffer.
  - Buffer length [1 byte, unsigned]
    * 1-256
  - Buffer [1-256 bytes]

=== 0x5 Write Buffer (long) ===
Same as above; long version;
  - Buffer length [2 bytes, unsigned]
    * 1-65536
  - Buffer [1-65536 bytes]

=== 0x6 Repeat Buffer ===
Writes a buffer of bytes repeating a number of times to the current offset of the modification buffer.
  - Repeat count [1 byte, unsigned]
    * 1-256
  - Buffer length [1 byte, unsigned]
    * 1-256
  - Buffer [1-256 bytes]

=== 0x7 Repeat Buffer (long) ===
Same as above; long version;
  - Repeat count [2 bytes, unsigned]
    * 1-65536
  - Buffer length [1 byte, unsigned]
    * 1-256
  - Buffer [1-256 bytes]

=== 0x8 Copy Vanilla Range ===
Copies a buffer of bytes from the unmodified buffer back to the current position in the modification buffer.
  - Parameters
    * ''10000000'':
      * 0 = Absolute Offset (unsigned)
      * 1 = Relative Offset (signed) 
    * ''00111000'': Offset byte size
    * ''00000111'': Copy length byte size
  - Offset [0-7 bytes, unsigned or signed, see first parameter]
  - Copy length [0-7 bytes, unsigned]
    * Read value is +1 (examples: ''0x00'' → 1, ''0xFF'' → 256)