How does one read file line by line / upto a specific delimeter of an MmFile?

[Adnan]

On Sunday, 15 March 2020 at 00:37:35 UTC, H. S. Teoh wrote:
> On Sat, Mar 14, 2020 at 10:37:37PM +0000, Adnan via 
> Digitalmars-d-learn wrote:
>> https://dlang.org/library/std/mmfile/mm_file.html doesn't seem 
>> to
>> specify anything similar to lines() or byLine() or 
>> byLineCopy() etc.
>
> That's because a memory-mapped file appears directly in your 
> program's memory address space as if it was an array of bytes 
> (ubyte[]).  No interpretation is imposed upon the contents.  If 
> you want lines out of it, try casting the memory to 
> const(char)[] and using std.algorithm.splitter to get a range 
> of lines. For example:
>
> 	auto mmfile = new MmFile("myfile.txt");
> 	auto data = cast(const(char)[]) mmfile[];
> 	auto lines = data.splitter("\n");
> 	foreach (line; lines) {
> 		...
> 	}
>
>
> T

Would it be wasteful to cast the entire content into a const 
string? Can a memory mapped file be read with a buffer?