JBB file format

⚠️ This format is Architecture-Dependant: This means if you are compiling a binary bundle in little-endian machine it will only work on little-endian machines!

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The JBB bundles are organised in 4 different streams, depending on the bit-length of the encoded data:

• 8-bit Stream [S8]: For Op-Codes, UINT8, INT8
• 16-bit Stream [S16]: For UINT16 and INT16
• 32-bit Stream [S32]: For UINT32, INT32 and FLOAT32
• 64-bit Stream [S64]: For FLOAT64

The master stream is the S8 on which the op-codes that define the structure of the encoded objects is stored. When an op-code argument has a type different than UINT8 or INT8, the appropriate stream will be used:

There are 3 additional higher-level structures in a JBB bundle:

• Header [HT]: A 32-byte long structure with the meta-data.
• String Table [ST]: A list of null-terminated strings used for compressing object keys.
• Signature Table [GT]: A list of string IDs that compose the keys for each plain-object encountered in the structure.
• Profile IDs [PT]: A list of profile signatures that were used to compile the bundle.

Compact (.jbb) and Sparse (.jbbp) Bundles

Since the streams are cleanly separated it's possible to speed-up the loading time by loading all 4 streams in parallel. In a compact bundle all 4 streams are merged in a single file, while in a sparse bundle each stream is written to a different file.

.jbb (Compact)	.jbbp (Sparse)
HT Header S64 64-Bit Stream S32 32-Bit Stream PT Profile IDs S16 16-Bit Stream GT Signature Table S8 8-Bit Stream ST String Table	*.jbbp *_b16.jbbp *_b32.jbbp *_b64.jbbp HT Header PT Profile IDs S32 32-Bit Stream S64 64-Bit Stream S8 8-Bit Stream S16 16-Bit Stream ST String Table GT Signature Table

Header Structure

Offset	+1	+2	+3	+4
0	magic		profile_id
4	version		profile_count
8	s64_length
12	s32_length
16	s16_length
20	s8_length
24	st_length
28	gt_length

The following fields are in the table:

• magic : magic number is a 16-bit unsigned integer with value 0x4231, so it's represented as <31h,42h> in machines with little-endian architecture or <42h,31h> in big-endian. It's therefore possible to detect incompatible endianess before loading the bundle.
• profile_id: If only 1 profile is used in the bundle, this field contains the signature ID of the profile. If more than 1 profile are used, this field should be 0x00.
• version: The version of the jbb encoder that created this bundle.
• profile_count: The number of profiles in the bundle.
• s64_length: The length (in bytes) of the 64-bit stream.
• s32_length: The length (in bytes) of the 32-bit stream.
• s16_length: The length (in bytes) of the 16-bit stream.
• s8_length: The length (in bytes) of the 8-bit stream.
• st_length: The length (in bytes) of the string table.
• gt_length: The length (in bytes) of the signature table.