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exercism fetch ruby circular-buffer

Circular Buffer

A circular buffer, cyclic buffer or ring buffer is a data structure that uses a single, fixed-size buffer as if it were connected end-to-end.

A circular buffer first starts empty and of some predefined length. For example, this is a 7-element buffer:

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[ ][ ][ ][ ][ ][ ][ ]

Assume that a 1 is written into the middle of the buffer (exact starting location does not matter in a circular buffer):

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[ ][ ][ ][1][ ][ ][ ]

Then assume that two more elements are added — 2 & 3 — which get appended after the 1:

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[ ][ ][ ][1][2][3][ ]

If two elements are then removed from the buffer, the oldest values inside the buffer are removed. The two elements removed, in this case, are 1 & 2, leaving the buffer with just a 3:

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[ ][ ][ ][ ][ ][3][ ]

If the buffer has 7 elements then it is completely full:

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[6][7][8][9][3][4][5]

When the buffer is full an error will be raised, alerting the client that further writes are blocked until a slot becomes free.

The client can opt to overwrite the oldest data with a forced write. In this case, two more elements — A & B — are added and they overwrite the 3 & 4:

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[6][7][8][9][A][B][5]

Finally, if two elements are now removed then what would be returned is not 3 & 4 but 5 & 6 because A & B overwrote the 3 & the 4 yielding the buffer with:

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[ ][7][8][9][A][B][ ]

For installation and learning resources, refer to the exercism help page.

For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:

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gem install minitest

If you would like color output, you can require 'minitest/pride' in the test file, or note the alternative instruction, below, for running the test file.

In order to run the test, you can run the test file from the exercise directory. For example, if the test suite is called hello_world_test.rb, you can run the following command:

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ruby hello_world_test.rb

To include color from the command line:

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ruby -r minitest/pride hello_world_test.rb

Source

Wikipedia http://en.wikipedia.org/wiki/Circular_buffer

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.