The `bits`

module acts on blobs.

use bits

from | thru | length | |
---|---|---|---|

bytes | bits | ||

-36028797018963968 | 10 | 80 | |

-562949953421312 | -36028797018963967 | 9 | 72 |

-4398046511104 | -562949953421311 | 8 | 64 |

-34359738368 | -4398046511103 | 7 | 56 |

-268435456 | -34359738367 | 6 | 48 |

-2097152 | -268435455 | 5 | 40 |

-16384 | -2097151 | 4 | 32 |

-128 | -16383 | 3 | 24 |

-1 | -127 | 2 | 16 |

0 | 127 | 1 | 8 |

128 | 16383 | 2 | 16 |

16384 | 2097151 | 3 | 24 |

2097152 | 268435455 | 4 | 32 |

268435456 | 34359738367 | 5 | 40 |

34359738368 | 4398046511103 | 6 | 48 |

4398046511104 | 562949953421311 | 7 | 56 |

562949953421312 | 36028797018963967 | 8 | 64 |

A blob can be in one of two states, either *antestone* or *stone*. In the mutable antestone state, the `write`

functions may be used to append bits to the blob. In the immutable stone state, bits can be harvested from the blob. Bits can be written to blobs as fixed size bit fields, that is a sequence of bits with a specified length, or as a Kim.

Kim is an encoding of fit numbers. Kim is a very simple encoding that delivers 7 bits per byte. The bottom 7 bits of each byte contain data, which can be accumulated to produce fit numbers. The top bit of each byte is `1`

if the byte is not the last and least byte of a number. The top bit of each byte is `0`

if the byte is the last byte of a number. The last byte contains the 7 least significant bits. A first byte of `0x80`

indicates negation.

The `kim_length`

function gives the length in bits of the Kim encoding of a `value`. If the value is a fit number, it gives a result as shown in the table. If `value` is a logical, it gives `1`

. If value is a text, it gives the length in bits of the Kim encoding of a `text`, giving the sum of the kim encodings of the length and each character. Otherwise, it gives `null`

.

The `write`

functions append bits to the end of an antestone blob.

Append a bit to the end of the `blob`. The `logical` value can be `true`

, `false`

, `1`

, or `0`

.
Any other value will disrupt.

Append `second_blob` to the end of `first_blob`.

Append a 64 bit DEC64 encoded number to a stone `blob`.

Append a bit field to the `blob`. If `fit` requires more bits than allowed by `length`, it disrupts.

Append a `fit` number or a single character as a kim value.

Append a `1`

bit to the antestone `blob` followed by enough `0`

bits to round up the `blob`'s length to a multiple of the `block_size`.

Append a text. This will be encoded as a kim encoded length followed by a sequence of kim encoded UTF-32 characters.

The read functions retrieve bits from a stone blob. The from arguments specifies the bit location at which to read. The beginning of the blob is `0`

.

Retrieve a 64 bit DEC64 encoded number from a stone `blob`.

Retrieve a Kim encoded fit number from a stone `blob`.

Retrieve a fit number from a bit field from a stone `blob`.

Retrieve a bit from the `blob`. If `blob` is not a stone blob, or if `from` is out of range, it returns `null`

.

Return `true`

if the stone `blob's` length is a multiple of the `block_size` (in bits), and if the difference between `length`

and `from` is less than or equal to the `block_size`, and if the bit at `from` is one, and that any remaining bits are zero.

Retrieve a Kim encoded text from a stone `blob`.