Variable Length Quantity
Implement variable length quantity encoding and decoding.
The goal of this exercise is to implement VLQ encoding/decoding.
In short, the goal of this encoding is to encode integer values in a way that would save bytes.
Only the first 7 bits of each byte is significant (right-justified; sort of like an ASCII byte).
So, if you have a 32-bit value, you have to unpack it into a series of 7-bit bytes.
Of course, you will have a variable number of bytes depending upon your integer.
To indicate which is the last byte of the series, you leave bit #7 clear.
In all of the preceding bytes, you set bit #7.
So, if an integer is between 0-127
, it can be represented as one byte.
Although VLQ can deal with numbers of arbitrary sizes, for this exercise we will restrict ourselves to only numbers that fit in a 32-bit unsigned integer.
Here are examples of integers as 32-bit values, and the variable length quantities that they translate to:
NUMBER VARIABLE QUANTITY
00000000 00
00000040 40
0000007F 7F
00000080 81 00
00002000 C0 00
00003FFF FF 7F
00004000 81 80 00
00100000 C0 80 00
001FFFFF FF FF 7F
00200000 81 80 80 00
08000000 C0 80 80 00
0FFFFFFF FF FF FF 7F
Running the tests
To run the tests run the command go test
from within the exercise directory.
If the test suite contains benchmarks, you can run these with the -bench
flag:
go test -bench .
Keep in mind that each reviewer will run benchmarks on a different machine, with
different specs, so the results from these benchmark tests may vary.
For more detailed information about the Go track, including how to get help if
you're having trouble, please visit the exercism.io Go language page.
Source
A poor Splice developer having to implement MIDI encoding/decoding. https://splice.com
Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.