README
¶
BSV
block separated values
BSV aims to be be a compact, typed binary format compatible with tabular formats like CSV, TSV, TAB and structured formats like JSON and JSON lines. Data stored in those formats should easily convert to and from the BSV format.
Control Blocks
BSV Control Blocks use a prefix coding scheme to indicate the type of the current byte (which then further indicates how many bytes the field contains). The intention is to minimize signaling overhead and pack as much data directly into the control block as possible.
BSV does not specify the contents of the data bits. The meaning of the data bits must come from some additional schema or specification supplied to the encoder/decoder.
This diagram indicates the bits that are fixed (filled in) vs bits that are available for encoding data (blanks). Data and size information is expected to be extracted by masking off the fixed bits. This is only the first byte (several control block types are multi-byte sequences).
| 0123 4567 | |
Type | Abbr | Min Bytes | Max Bytes |
|---|---|---|---|---|
| 1... .... | |
Data | d |
1 | 1 |
| 01.. .... | |
Data Size | dz |
2 | 65 |
| 001. .... | |
Data + 1 | d1 |
2 | 2 |
| 0001 .... | |
Data + 2 | d2 |
3 | 3 |
| 0000 1... | |
Data Size Size | dzz |
3 | 9 + $2^{64}$ |
| 0000 01.. | |
Container | cs cb cu ce |
2 | ∞ |
| 0000 001. | |
Skip Size | sz |
2 | 3 |
| 0000 0001 | |
Empty | e |
1 | 1 |
| 0000 0000 | |
Null | n |
1 | 1 |
Data and size embedded in the control block is extracted by masking all control
bits to zero. For example 1|000_0001 decodes to 0000_0001 and 001|1_0001 0000_0000 decodes to 0001_0001 0000_0000.
Some of the types have overlapping ranges. For example, 8-bits of data can be
stored in either of dz, d1, d2, or dzz blocks. Encoders optimizing
overhead will prefer the most compact type (d1), but they are not required
to. This allows encoders to make trade offs for different optimization choices
like maximizing encoding speed or minimizing mutable field updates causing
rewrites of all following data.
The blocking structure has the following absolute and efficient
data-to-total-bytes ratios. The absolute values are a direct consequence of the
entire encodable range for that block type. The efficient values are what you
would expect if picking the block type with the lowest overhead for the amount
of data. For example, data with 14 to 20 bits would be stored more efficiently
in a d2 block rather than a dz or dzz block.
| Type | Abs. Data | Abs. Data % | Eff. Data | Eff. Data % |
|---|---|---|---|---|
d |
7 bits | 88.5% | 7 bits | 88.5% |
dz |
1 - 64 bytes | 50% - 98.4% | 3 - 64 bytes | 75% - 98.4% |
d1 |
13 bits | 81.3% | 13 bits | 81.3% |
d2 |
20 bits | 83.3% | 20 bits | 83.3% |
dzz |
1 - $2^{64}$ bytes | 33.3% - ~100% | 65 - $2^{64}$ bytes | 97.0% - ~100% |
All sizes are big-endian and indexed starting at 1 to maximize their effective
range. To encode zero length data (e.g. empty string) use the Empty
block. For example, a size of 1 in a Data Size block is encoded
as 01|00_0000 and size 2 as 01|00_0001.
Data
| Abbreviation | d |
| Capacity | $2^7$ = 128 values |
Data blocks allow for 7 bits of data to be encoded directly into the block. Encoding up to 128 values (e.g. booleans, signed integers between -64 and +64).
. .
|0 1 2 3 4 5 6 7|
+-+-+-+-+-+-+-+-+
|1| data |
+-+-+-+-+-+-+-+-+
For example, the following could represent boolean values:
. .
|0 1 2 3 4 5 6 7|
+-+-+-+-+-+-+-+-+
|1|0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+
^
|
* boolean false
. .
|0 1 2 3 4 5 6 7|
+-+-+-+-+-+-+-+-+
|1|0 0 0 0 0 0 1|
+-+-+-+-+-+-+-+-+
^
|
* boolean true
Data Size
| Abbreviation | dz |
| Capacity | $2^6$ = 1 to 64 bytes; $2^{512}$ values |
Data Size blocks have two parts:
- Number of bytes that contain data
- Data
Data Size blocks allow for up to 64 bytes of data. They are meant to efficiently encode short data sequences like short strings or medium sized numbers.
.0 . 1 1. .6 7 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5| |4 5 6 7 8 9 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
|0 1| size | 1-64 bytes data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
Examples:
.0 . 1 . 2 . 3 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 1|0 0 0 0 1 0| 3 bytes data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size = 3
.0 . 1 1. .6 7 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5| |4 5 6 7 8 9 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
|0 1|1 1 1 1 1 1| 64 bytes data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
size = 64
Data + 1
| Abbreviation | d1 |
| Capacity | $2^{5+8}$ = $2^{13}$ = 8,192 values |
Data + 1 blocks are two byte sequences containing data. They allow for 13 bits of data to be encoded with up to 8,192 values (e.g. signed integers between -4,096 and +4,096).
.0 . 1 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 1| 13 bits data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data + 2
| Abbreviation | d2 |
| Capacity | $2^{4+8+8}$ = $2^{20}$ = 1,048,576 values |
Data + 2 blocks are three byte sequences containing data. They allow for 20 bits of data to be encoded with up to 1,048,576 values (e.g. integers between -524,288 and +524,288).
.0 . 1 . 2 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1| 20 bits data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Data Size Size
| Abbreviation | dzz |
| Capacity | $2^3$ = 1 to 8 bytes size; $2^{8*8}$ = $2^{64}$ = 16 EiB |
Data Size Size blocks have 3 parts:
- Number of bytes for the data size
- Number of bytes that contain data
- Data
Data Size Size blocks allow for up to 16 EiB (exbibytes) of data.
.0 . 1 1. . . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++
|0 0 0 0 1| Z | 1-8 bytes size | 1-16 EiB data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++
Z: bytes of size
Examples:
2 2 2
0 0 0
.0 . 1 . 2 2. .4 5 5.
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3| |7 8 9 0 1 2 3 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
|0 0 0 0 1|0 0 0|1 1 1 1 1 1 1 1| 256 bytes data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
bytes of size = 1
size = 256
Skip Size
| Abbreviation | sz |
| Capacity | $2^1$ = 1 to 2 bytes; $2^{(2*8)}$ = $2^{16}$ = 65,536 fields |
Skip Size blocks have two parts:
- Number of bytes that contain skip
- Skip amount
Skip Size blocks indicate that up to 65,536 contiguous fields aren't directly encoded in the byte stream. The specific meaning of what the skipped fields contain is schema and encoding dependent. This is meant to allow efficient encoding of sparse data (e.g. sparse matrices, delta encoded values).
.0 . 1 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1|0| amount |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size = 1
.0 . 1 . 2 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1|1| amount |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size = 2
Example with 1 byte skip size and 16 fields of skip:
.0 . 1 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 1|0|0 0 0 0 1 1 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size = 1
skip = 16
Empty
| Abbreviation | e |
Empty blocks indicate that the field is set to the empty value (e.g. an empty string, integer zero).
.0 .
|0 1 2 3 4 5 6 7|
+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 1|
+-+-+-+-+-+-+-+-+
Null
| Abbreviation | n |
Null blocks indicate that the field is set to the null value (e.g. an optional string).
.0 .
|0 1 2 3 4 5 6 7|
+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+
Container
Container blocks signal the start and end of an embedded BSV. There are two types of container blocks for known size (bounded) and unknown size (unbounded) situations.
| 0123 4567 | |
Type | Abbr |
|---|---|---|
| 0000 0111 | |
Container Symmetric | cs |
| 0000 0101 | |
Container Bounded | cb |
| 0000 0110 | |
Container Unbounded | cu |
| 0000 0100 | |
Container End | ce |
Container Bounded
| Abbreviation | cb |
| Capacity | $2^{(2^{64}*8)}$ = $2^{(2^{64}*2^3)}$ = $2^{2^{(64+3)}}$ = $2^{2^{67}}$ = $2^{134}$ bytes |
Bounded containers have 3 parts:
- Control Block Container Bounded
- Size encoded in a single BSV field
- An embedded BSV
The largest bounded container would use a size encoded in a dzz block
with $2^{64}*8$ bits and an embedded BSV of $2^{(2^{64}*8)}$ bytes.
.0 . 1 1. . . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++
|0 0 0 0 0 1|0 1| size as BSV field | BSV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++
^
|
* `cb` block
Bounded containers can be efficiently seeked past if the embedded data isn't needed immediately.
A bounded block with an embedded BSV (e.g. a struct with a single boolean field set to true):
.0 . 1 . 2 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|0 1|1|0 0 0 0 0 0 0|1|0 0 0 0 0 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^ ^
| | |
| | * boolean true in a `d` block
| |
| * 1 byte size in a `d` block
|
* `cb` block
A bounded block that is empty (e.g. an empty struct):
.0 . 1 1.
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|0 1|0 0 0 0 0 0 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^
| |
| * `e` block
|
* `cb` block
This is equivalent to the longer form:
.0 . 1 . 2 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|0 1|1|0 0 0 0 0 0 0|0 0 0 0 0 0 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^ ^
| | |
| | * `e` block
| |
| * 1 byte size in a `d` block
|
* `cb` block
A bounded block that is null (e.g. a pointer to a struct):
.0 . 1 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|0 1|0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^
| |
| * `n` block
|
* `cb` block
This is also equivalent to the longer form:
.0 . 1 . 2 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|0 1|1|0 0 0 0 0 0 0|0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^ ^
| | |
| | * `n` block
| |
| * 1 byte size in a `d` block
|
* `cb` block
NOTE: Depending on the semantic needs of the encoder/decoder and the capabilities of the schema it may be sufficient to simply use the Empty and Null blocks directly (instead of embedding them in a Container block).
Container Unbounded
| Abbreviation | cb ce |
| Capacity | ∞ |
cu ce
Unbounded containers blocks have 3 parts:
- Control Block Container Being Unbounded
- An embedded BSV
- Control Block Container End
Processing unbounded blocks requires counting the open and closing blocks to ensure they are properly paired. Seeking past the data requires scanning the bytes to find the closing block.
.0 . 1 1. . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 0| BSV |0 0 0 0 0 1|0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+
^ ^
| |
* `cu` block * `ce` block
An unbounded block with an embedded BSV (e.g. an array of integers):
.0 . 1 . 2 . 3 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 0|1|0 0 0 0 0 0 0|1|0 0 0 0 0 0 1|0 0 0 0 0 1|0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ \ / ^
| ----------------------------- |
| ^ * `ce` block
| |
| * embedded BSV with two fields
|
* `cu` block
Container Symmetric
| Abbreviation | cs |
Container Symmetric blocks indicate that the next field will be encoded symmetrically. Symmetric encoding makes the field readable in reverse (as well as forwards).
Container Symmetric blocks have 5 parts:
- Container Symmetric Control Block
- Forward Control Blocks
- Data
- Reverse Control Blocks
- Container Symmetric Control Block
- Reverse decoding should processes control and data the same way as forward with the exception that control blocks with data bits are prepended rather than appended.
- The same number and type of control blocks must be read when processing in reverse as forward. Any data bits must be identical between the forward and reverse control blocks.
All single byte control blocks are already symmetric and do not have a symmetric specific form. Explicitly these are the control blocks:
- Data
- Empty
- Null
Container Unbounded blocks are also already symmetric. This means Container Unbounded blocks are identical to their non-symmetric form in presentation. The difference is that during reverse decoding the pair matching logic is inverted.
| Abbreviation | (dz) |
| Capacity | 1-64 bytes |
.0 . 1 1. . . . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5| | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 1| size | 1-64 bytes data |0 1| size |0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^
| |
* `cs` block * `cs` block
Example Symmetric Data Size block with size 2:
.0 . 1 . 2 . 3 . .4 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|2 3 4 5 6 7 8 9|0 1 2 3 4 5 6 7|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 1|0 0 0 0 0 1| 2 bytes data |0 1|0 0 0 0 0 1|0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size = 2
| Abbreviation | (d1) |
| Capacity | 13 bits |
A Symmetric Data + 1 block:
.0 . 1 . 2 . 3 . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|2 3 4 5 6 7 8 9|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 1| data | data |0 0 1| data |0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Abbreviation | (d2) |
| Capacity | 20 bits |
A Symmetric Data + 2 block:
.0 . 1 . 2 . 3 . .4 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|2 3 4 5 6 7 8 9|0 1 2 3 4 5 6 7|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 0 1| data |0 0 0 1| data |0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Abbreviation | (dzz) |
| Capacity | $2^3$ = 1 to 8 bytes size; $2^{8*8}$ = $2^{64}$ = 16 EiB |
A Symmetric Data Size Size block:
.0 . 1 . 2 2. . . . . . . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3| | | | | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 0 0 1| Z | 1-8 bytes size | 1 - ~16 EiB data | 1-8 bytes size |0 0 0 0 1| Z |0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Z: bytes of size
Example block with 1 byte of size and 254 bytes of data:
2 2 2
0 0 0
.0 . 1 1. 2 2. . .7 .8 . 9 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3| | |2 3 4 5 6 7 8 9|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 0 0 1|0 0 0|1 1 1 1 1 1 1 1| 256 bytes |1 1 1 1 1 1 1 1|0 0 0 0 1|0 0 0|0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^ ^ ^
| | | |
| \ / |
| `---------------* size = 256 *----------------' |
\ /
`-----------------------* bytes of size = 1 *---------------------------------'
.0 . 1 1. . . . . . . . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5| | | | | | | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 0 0 0 1|0 1| size as BSV field | BSV | size as BSV field |0 0 0 0 0 1|0 1|0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+++++++++++++++++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
NOTE: The size field must also be symmetric.
Example block with size 3 (1 data byte):
.0 . 1 . 2 . 3 . .4 . 5 .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|2 3 4 5 6 7 8 9|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 0 0 0 1|0 1|1|0 0 0 0 0 0 0|1|0 0 0 0 0 0 1|1|0 0 0 0 0 0 0|0 0 0 0 0 1|0 1|0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
^ ^ ^ ^ ^
| | | | |
| | * bsv | |
| \ / |
| `--* size = 1 in `d` block *--' |
\ /
`------------------------* `cb` block *-----------------------'
.0 . 1 . 2 . 3 . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|2 3 4 5 6 7 8 9|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 0 0 0 0 1|0| amount |0 0 0 0 0 0 1|0|0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size = 1
Example block with size 1 (skip 16 fields):
.0 . 1 . 2 . 3 . .
|0 1 2 3 4 5 6 7|8 9 0 1 2 3 4 5|6 7 8 9 0 1 2 3|4 5 6 7 8 9 0 1|2 3 4 5 6 7 8 9|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1|1 1|0 0 0 0 0 0 1|0|0 0 0 0 1 1 1 1|0 0 0 0 0 0 1|0|0 0 0 0 0 1|1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size = 1
skip = 16
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