Avoid deallocate empty arrays?

[IGotD-]

On Thursday, 17 December 2020 at 17:46:59 UTC, Steven 
Schveighoffer wrote:
>
> This isn’t correct. Can you post the code that led you to 
> believe this?
>
> -Steve

Sure.


import std.algorithm;
import std.typecons;
import std.stdio;


struct Buffer
{
	this(size_t size)
	{
		m_buffer.reserve = size;
	}


	void add(const void[] arr)
	{
		m_buffer ~= cast(ubyte[])arr;
	}


	string getSome()
	{
		if(m_buffer.length > 0)
		{
			return cast(string)m_buffer[0..$];
		}
		else
		{
			return "";
		}
	}

	void remove(size_t size)
	{
		m_buffer = m_buffer.remove(tuple(0, size));
	}

	ubyte[] m_buffer;
}

void main()
{
	Buffer b = Buffer(16);
	
	b.add("aa");

	writeln("b.m_buffer.length ", b.m_buffer.length, ", 
b.m_buffer.capacity ", b.m_buffer.capacity);

	string s = b.getSome();

	assert(s == "aa");

	b.remove(s.length);

	writeln("b.m_buffer.length ", b.m_buffer.length, ", 
b.m_buffer.capacity ", b.m_buffer.capacity);
}

This will print

b.m_buffer.length 2, b.m_buffer.capacity 31
b.m_buffer.length 0, b.m_buffer.capacity 0

capacity 0, suggests that the array has been deallocated.