Bitstrings: Processing Bit-Level Data
Pattern matching on bitstrings works at a bit level, so we can pack and unpack sequences of bits into a bitstring in a single operation. This is extremely useful when writing code that needs to manipulate bit-level data, such as with data that is not aligned to 8-bit boundaries, or variable-length data, where the data length is expressed in bits rather than bytes.
We can illustrate bit-level processing in the shell.
| | 1> B1 = <<1:8>>. |
| | <<1>> |
| | 2> byte_size(B1). |
| | 1 |
| | 3> is_binary(B1). |
| | true |
| | 4> is_bitstring(B1). |
| | true |
| | 5> B2 = <<1:17>>. |
| | <<0,0,1:1>> |
| | 6> is_binary(B2). |
| | false |
| | 7> is_bitstring(B2). |
| | true |
| | 8> byte_size(B2). |
| | 3 |
| | 9> bit_size(B2). |
| | 17 |
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