Misty Programming Language:

bits Functions

The bits module acts on blobs.

use bits
Kim lengths for fit values
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.

Functions

bits.logical(blob, from)

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

bits.number(blob, from)

Retrieve a Kim encoded fit number from a stone blob.

bits.number(blob, from, length)

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

bits.pad?(blob, from, block_size)

Return true if the stone blob's length is a multiple of the block_size, 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.

bits.text(blob, from)

Retrieve a Kim encoded text from a stone blob.

Write functions

The write functions append bits to the end of an antestone blob.

bits.write(first_blob, second_blob)

Append second_blob to the end of first_blob.

bits.write(blob, logical)

Append a bit to the end of the blob.

bits.write(blob, fit)

Append a fit number as a kim value.

bits.write(blob, fit, length)

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

bits.write(blob, text)

Append a text.

bits.pad(blob, block_size)

Append a 1 bit to the antestone blob followed by enough zero bits to round up the blob's length to a multiple of the block_size.

bits.kim(value)

The kim function gives the length in bits of the Kim encoding of a fit number value. 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.