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Michel Keijzers
Michel Keijzers
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I don't think that this library is supported by attiny (or even Arduino in general).

However, beyond that, it is not advised to use it, since it is uncertain how much memory and flash overhead it consumes.

Especially the memory is an issue for two reasons:

  • Internally, you don't know the exact data structures used for the list. In most efficient way, it will only use 4 bytes (4 times 1 byte for the array), however, since it is a class under the hood a vtable is added, and who knows what more memory (maximum capacity, current capacity of the list etc).
  • Also when adding/removing an item from the list, either the entire list is copied, or some tricks with pointers are used. In the first case you get memory gaps, in the second case maybe (and additional memory for the pointers is used).

My advice is to use just a simple array, and define a maximum of the array at compile time (if possible). Not as flexible, but robust, less memory usage and more reliable with a low SRAM device like the Attiny (and Arduino in general).

Removing elements

Based on your first comment:

Removing items is indeed an issue, however, note that if you use the standard library it might copy the entire array (excluding) the new item, so temporarily you will have double the array AND a memory gap.

There are some ways to implement it yourself:

  • If you only want to remove items (and never add), add a new array with booleans that denote which are present and which are deleted (e.g. deleted[4] = 1 means that item 4 is deleted. This only cost 1 bit per element.
  • Use two arrays with items, and copy them back and forth each time. This will cause not really a memory gap, but you need the storage needed for two arrays. And keep a variable which of the two arrays is the 'current'.

I don't think that this library is supported by attiny (or even Arduino in general).

However, beyond that, it is not advised to use it, since it is uncertain how much memory and flash overhead it consumes.

Especially the memory is an issue for two reasons:

  • Internally, you don't know the exact data structures used for the list. In most efficient way, it will only use 4 bytes (4 times 1 byte for the array), however, since it is a class under the hood a vtable is added, and who knows what more memory (maximum capacity, current capacity of the list etc).
  • Also when adding/removing an item from the list, either the entire list is copied, or some tricks with pointers are used. In the first case you get memory gaps, in the second case maybe (and additional memory for the pointers is used).

My advice is to use just a simple array, and define a maximum of the array at compile time (if possible). Not as flexible, but robust, less memory usage and more reliable with a low SRAM device like the Attiny (and Arduino in general).

I don't think that this library is supported by attiny (or even Arduino in general).

However, beyond that, it is not advised to use it, since it is uncertain how much memory and flash overhead it consumes.

Especially the memory is an issue for two reasons:

  • Internally, you don't know the exact data structures used for the list. In most efficient way, it will only use 4 bytes (4 times 1 byte for the array), however, since it is a class under the hood a vtable is added, and who knows what more memory (maximum capacity, current capacity of the list etc).
  • Also when adding/removing an item from the list, either the entire list is copied, or some tricks with pointers are used. In the first case you get memory gaps, in the second case maybe (and additional memory for the pointers is used).

My advice is to use just a simple array, and define a maximum of the array at compile time (if possible). Not as flexible, but robust, less memory usage and more reliable with a low SRAM device like the Attiny (and Arduino in general).

Removing elements

Based on your first comment:

Removing items is indeed an issue, however, note that if you use the standard library it might copy the entire array (excluding) the new item, so temporarily you will have double the array AND a memory gap.

There are some ways to implement it yourself:

  • If you only want to remove items (and never add), add a new array with booleans that denote which are present and which are deleted (e.g. deleted[4] = 1 means that item 4 is deleted. This only cost 1 bit per element.
  • Use two arrays with items, and copy them back and forth each time. This will cause not really a memory gap, but you need the storage needed for two arrays. And keep a variable which of the two arrays is the 'current'.
Source Link
Michel Keijzers
Michel Keijzers
  • 13k
  • 7
  • 43
  • 59

I don't think that this library is supported by attiny (or even Arduino in general).

However, beyond that, it is not advised to use it, since it is uncertain how much memory and flash overhead it consumes.

Especially the memory is an issue for two reasons:

  • Internally, you don't know the exact data structures used for the list. In most efficient way, it will only use 4 bytes (4 times 1 byte for the array), however, since it is a class under the hood a vtable is added, and who knows what more memory (maximum capacity, current capacity of the list etc).
  • Also when adding/removing an item from the list, either the entire list is copied, or some tricks with pointers are used. In the first case you get memory gaps, in the second case maybe (and additional memory for the pointers is used).

My advice is to use just a simple array, and define a maximum of the array at compile time (if possible). Not as flexible, but robust, less memory usage and more reliable with a low SRAM device like the Attiny (and Arduino in general).